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The Alabama Age-Related Macular Degeneration Grading System for Donor Eyes Christine A. Curcio,1'2 Nancy E. Medeiros,5 and C. Leigh Millican1 develop a systematic method for identifying and grading age-related macular degeneration (ARMD) in human donor eyes, postmortem fundus appearance was compared with histopathologic assessment in eyes with a spectrum of age-related macular change. PURPOSE. TO METHODS. Eyes without grossly visible, late ARMD were obtained from 8 cancer patients and 26 donors older than 50 years. Postmortem fundus appearance was graded for drusen and pigmentary change, using stereo color photographs. Eyes were processed and sectioned at 1 jam for histopathologic evaluation of macular retinal pigment epithelium-Bruch's membrane complex. The histologic diagnosis was compared with gross fundus appearance, clinical ophthalmic histories (n — 25), and clinical fundus photographs that were graded using the Wisconsin Age-related Maculopathy Grading System (n = 5). Ten eyes met histopathologic criteria for early ARMD. A similar proportion of eyes (27%-32%) was identified as affected by ARMD by other published histopathologic criteria. By choosing eyes with at least one druse larger than 125 jam in diameter or an area of pigmentclumping 500 /Ltm in diameter that was visible in the postmortem fundus, ARMD cases were identified with 90% sensitivity and 95% specificity. RESULTS. CONCLUSIONS. The Alabama ARMD Grading System permits rational and standardized use of donor eyes in studies that are directed toward understanding the pathogenesis of ARMD. (Invest Opbthalmol VisSci. 1998;39:1085-1096) ge-related macular degeneration (ARMD), a disorder of the macular area involving the retinal pigment epithelium (RPE), Bruch's membrane, and photoreceptors, is a major cause of vision loss in the elderly.' Current animal models2'3 do not exhibit the complete range of pathologic features of ARMD. There is a critical need for a well-designed study of human eyes with ARMD, particularly those with early stages of disease, to guide informed development of improved animal models. Precise assignment of maculopathy status is of paramount importance in case- control studies of human tissues. In eyes obtained from eye bank donors, maculopathy status has been denned by available clinical history, histopathologic assessment, or both.4'5 In contrast, study patients in current clinical epidemiologic ARMD research are characterized and staged by semiquantitative grading of standardized fundus photographs.6'7 These long-term studies provide valuable information about ARMD natural history, including identification of fundus features indicating high risk for severe disease.8"10 The process of relating morphologic, biochemical, and histochemical findings in donor eyes to work in other A From the Departments of 'Ophthalmology and 2Physiologic Optics, University of Alabama at Birmingham; and 3Retina and Vitreous Associates of Alabama, Huntsville. Supported by grant EY06109 from the National- Institutes of Health, Bethesda, Maryland; a grant from the Research to Prevent Blindness, New York, New York (CAC); and a grant from the Helen Keller Eye Research Foundation (NEM). Submitted for publication July 24, 1997; revised November 14, 1997 and January 12, 1998; accepted February 11, 1998. Proprietary interest category: N. Reprint requests: Christine A. Curcio/Department of Ophthalmology, University of Alabama at Birmingham, AL 35294-0009. disciplines would therefore benefit from information about the fundus appearance of donor eyes used. Because fundus photographs of donor eyes taken before death are not routinely available, we sought a systematic method for grading macular degeneration, using stereo color photographs of the postmortem fundus. In this study, we evaluated postmortem fundus appearance and RPE-Bruch's membrane disease in well-preserved eyes with different degrees of age-related macular change. We validated fundus grades by determining sensitivity and specificity for true ARMD cases identified by histopathologic evaluation. We also calibrated the number of ARMD cases against the number identified by other ARMD standards, including published histopathologic criteria,11"14 clinical history, and grades for clinical fundus photographs.715 Validation and calibration of a new ARMD grading system are difficult because clinicians, epidemiologists, and pathologists use different definitions and even different names for ARMD (for review, see Bird et al.15). There is reasonable agreement that the late form of ARMD includes changes that are either exudative (RPE or neurosensory retinal detachments, choroidal neovascular membranes with or without hemorrhages, exudates, and disciform scars) or nonexudative (geographic atrophy). 4121416 In contrast, early ARMD is variably defined (Table 1), with the absence of late ARMD being the only point of agreement. Histopathologic definitions of early ARMD include the type or number of drusen and may include basal deposits, RPE changes, or photoreceptor degeneration."" 14 Epidemiologic studies17"19 based on the Wisconsin Age-related Maculopathy Grading System (WARMGS) for clinical fundus photographs717 include drusen type and changes in RPE. The cross-disciplinary comparison in Table 1 arranges Investigative Ophthalmology & Visual Science, June 1998, Vol. 39, No. 7 Copyright © Association for Research in Vision and Ophthalmology Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1085 1086 Curcio et al. IOVS, June 1998, Vol. 39, No. 7 TABLE 1. Definitions for Early ARMD: Decision Criteria Author/Study 14 Type* Drusen Logical Ope\ Operator Spraul et al. Blue Mountain Eye Study19 H E-C Numerous Soft, indistinct AND OR Beaver Dam Eye Study17 E-C Soft, indistinct OR Green and Enger12 International System15 Ramrattan et al.'' H E-C H Soft Soft Numerous AND OR RPE Changes Grossly visible hypopigmentation or hyperpigmentation Hypopigmentation or hyperpigmentation; soft distinct drusen Hypopigmentation or hyperpigmentation; hard distinct drusen or worse RPE or photoreceptor degeneration Hypopigmentation or hyperpigmentation; drusen None required ARMD, age-related macular degeneration; RPE, retinal pigment epithelium. "Type of study: H, histopathologic, using sections; E-C, epidemiology-clinical, using fundus photographs. All definitions exclude late ARMD. Definitions are compared only for lesions visible in sections and in fundus. All histopathologic definitions permit soft or numerous drusen or basal deposits. early ARMD definitions in order from the most restrictive (identifying the fewest cases) to the least restrictive (identifying the most cases). Definitions requiring that eyes meet two criteria14 will identify fewer cases than definitions requiring that eyes meet only one criterion.l' By similar logic, definitions that include only a subset of soft drusen17 will identify fewer cases than will definitions that include any soft drusen. 1215 Cases identified by different criteria are at slightly different stages of disease, possibly underlying discrepant results across studies." 14 To produce a histopathologic definition of early ARMD to use as a reference standard for postmortem fundus grading, we developed decision rules for histologic analysis logically similar to those used for analysis of clinical fundus photographs. We applied these rules to a group of quickly preserved donor and surgically removed eyes with a spectrum of age-related macular change. We then determined the best criteria for selecting histologically confirmed ARMD eyes by postmortem fundus appearance. Our overall goal was to define early ARMD in terms of histopathologic features and fundus appearance, so that as many of the same eyes as possible would be considered ARMD by both methods. METHODS Our use of human tissues and clinical records was approved by institutional review at the University of Alabama at Birmingham. Tissue Collection and Photography Our goal was to assemble a group of rapidly preserved eyes with a spectrum of age-related macular change that would be subjected to postmortem fundus photography and subsequent histopathologic evaluation. To test the ability of the proposed grading scheme to discriminate between eyes affected by ARMD (ARMD eyes) and those without macular disease (nonARMD eyes), we sought similar numbers of age-matched eyes from donors older than 50 years, with and without grossly visible drusen and pigmentary change. A secondary goal was to maximize the number of eyes with clinical histories. Our results are based on the analysis of 34 eyes from 14 women and 20 men older than 50 years. Eyes were obtained from 26 human donors and from 8 cancer patients, who had undergone orbital exenteration for the removal of craniofacial tumors. No donors or patients had diabetes. Median time to preservation was 2 hours, 25 minutes (range, 1 hour 5 minutes to 3 hours, 24 minutes) for donor eyes and 23 minutes (range, 6 to 40 minutes) for surgery eyes. The majority of eyes (n = 25) came from a series of 57 consecutive donors or patients accessioned between August 1995 and April 1996. Maculopathy status was unknown at the time of accession, except for three donors who had histories of ARMD. During that period, each surgical eye or one randomly chosen eye from each donor was preserved for this study and underwent postmortem fundus photography (see later description). Eyes from 24 donors in the consecutive series were excluded from photography for the following reasons: patient younger than 50 years (n = 8), other grossly visible or clinically documented macular disease (myopia, Roth's spots, exudates, central retinal vein occlusion; n = 5), anterior segment surgery without clinical history (n = 3), late ARMD (geographic RPE atrophy and fibrovascular scars; n = 2), normal eyes in age groups for which there were enough specimens (n — 2), large folds in the fovea caused by postmortem edema (n = 2), and patient too old for agematching (n = 1). Of the eyes of 33 donors and patients that were photographed, 7 with gradable photographs were excluded from histopathologic evaluation because they were grossly normal eyes without history or were in age groups for which there were enough specimens (n = 5), or were damaged in processing (n = 2). Nine additional eyes from nonconsecutive donors and patients (December 1994-March 1997) were photographed and sectioned to complete the study group. These eyes had prominent drusen or pigmentary change (n = 6) or were normal with clinical histories (n = 3). Thus, eyes were excluded from the consecutive series and nonconsecutive eyes were included to meet the overall goals of the study design. After removal of the cornea and lens, globes were fixed by immersion for 24 to 48 hours in 0.1 M phosphate-buffered 1% paraformaldehyde and 2.5% glutaraldehyde (n = 27), 4% paraformaldehyde and 0.5% glutaraldehyde (w = 5), or 4% paraformaldehyde (n = 2). Preserved globes were examined internally after removal of superior and inferior calottes, anterior segment, and vitreous. At this time, we took stereo color photographs of posterior poles to specify early ARMD lesions. A horizontal belt containing the macula was stabilized in a 5-ml Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 Grading ARMD Donor Eyes IOVS, June 1998, Vol. 39, No. 7 polystyrene cup and submerged in 0.1 M phosphate buffer to reduce glare. We used a stereo microscope (model SMZ-U; Nikon, Melville, NY) with a side port extension that allowed us to produce stereo pairs and high-speed 35-mm film (Ektachrome EPJ320T; Eastman Kodak, Rochester, NY). We illuminated specimens in front of the retina with a fiber optic ring light and behind the sclera with a dark-field base (epi-illumination and transillumination, respectively). Standard photographs consisted of two stereo pairs at final magnifications on the slide of X3 and X5.6 (see later description), respectively, both taken with epi-illumination and transillumination at full power (150 W). Supplementary photographs were taken with epiillumination or transillumination only to emphasize drusen or pigmentary changes, respectively, in some eyes. Clinical Histories and Fundus Photographs Ophthalmic histories were obtained through eye bank-mediated letters to donor families and follow-up with eye doctors. Histories were reviewed by a retina specialist (NEM) to exclude eyes with a history of chorioretinal disease that could have been confused with early ARMD, such as high myopia, epimacular proliferation, or other inherited retinal degeneration. In addition, we sought to compare our histopathologic results with clinical findings. We emphasize that the histories available for eye donors vary considerably in reliability and validity. These records would be inadequate for clinical or epidemiologic research, but they are typical of information that is available for eye donors. As such, they are useful only for determining a general level of visual function. Photographs taken before surgery or death were obtained for five eyes. To calibrate our results against current epidemiologic practice, these photographs were evaluated by five graders experienced in applying the WARMGS to the Beaver Dam Eye Study (BDES)17 or to the Age-Related Eye Disease Study. Graders were unaware of patient history or histopathologic findings. Maculopathy status was assigned by the graders using BDES criteria17 (Table 1). The same grades were used to assign maculopathy status by criteria of the International System.15 Grading Postmortem Fundus Appearance Stereo color photographs of the postmortem macula were graded independently by two authors (CAC, NEM) before histologic analysis. We standardized the magnification of our 35-mm slides by photographing a ruler at different magnifications on the stereo microscope until 6 mm on the photograph matched the diameter of the outer circle on a standard WARMGS grid (nominally, 6000 jam on the retina). We created acetate overlays with appropriately scaled grids and measuring circles, using a software program (IntelliDraw; Aldus, Seattle, WA). An overlay with WARMGS grid was centered and taped to the left slide of the X 3 stereo pair. Donor or patient identity was masked, and photographs were graded using a X4 viewer. Tissue quality was assessed at three levels: 0, details of RPE visible through a clear retina across the macula; 1, details visible through the thin fovea and less visible through the thick parafovea; and 2, details not visible in fovea or parafovea. Eyes with grade 2 tissue quality were considered ungradable. Lesions were graded as absent, questionable, or present within the grid. Lesions visible in the X5.6 stereo pair but not in the X3 pair were considered questionable. Lesion size in the X3 1087 stereo pair was determined by fitting to circles 63 jam to 500 jam in diameter in a second overlay.15 The size of the largest druse and predominant drusen were graded (<63 jam, 63-125 jam, and >125 jam). We also graded the total number (1-5, 6-10, 11-20, >20), the main and most central subfields, and percentage of coverage by drusen in these subfields. With regard to RPE changes, we graded the presence, location, and size of hypopigmentation and hyperpigmentation. The latter was defined as focal pigment clumps extending anteriorly into the subretinal space or retina. For three or more discrete pigment clumps, we graded the size of the bounding circle. Histopathologic Assessment The macular retina, RPE, choroid, and sclera were divided horizontally with a razor, just superiorly to the foveal depression. The inferior half of each macula was subdivided into blocks containing the fovea, temporal parafovea, and nasal parafovea, which were osmicated, dehydrated, and embedded in Epon-Araldite using standard procedures. The foveal and temporal parafoveal blocks were serially sectioned at 1 jam with a diamond Histo knife and stained with toluidine blue. We examined two to three groups of serial sections that were at least 60 /xm apart through the foveal rod-free zone. We used a X60 objective, ocular reticules, and stepper motor stage with digital readout of position. Histopathologic assessment of the foveal and temporal parafoveal blocks focused on lesions thought to be associated with declining visual prognosis in ARMD. These lesions were deposits in the inner aspect of Bruch's membrane/112'20 large or confluent drusen,8'21 and focal hyperpigmentation of RPE.810 We used published semiquantitative grading methods4'20 where possible (Table 2). Deposits internal to the basal lamina of the RPE (basal laminar deposits)22 and those in the inner collagenous zone of Bruch's membrane (basal linear deposits)12 are indistinguishable in routine paraffin-embedded sections.l2 Therefore, to identify cases in a manner comparable to that used by other investigators, we did not distinguish between them in our 1-jam sections, and we graded total basal deposits, a combination of the two lesions (Table 2). We measured the size of the largest druse and predominant drusen, defined as focal deposits in the inner collagenous zone that raised the RPE by half its typical height. In the case of confluent drusen, size was measured for individual foci. For descriptive purposes only, drusen shape and contents were noted. Although RPE changes such as clumping and atrophy are important sequelae of early-appearing basal deposits,l3 these changes have not been included in previous grading schemes.4'20 We graded the morphologic appearance of RPE (Table 2), treating changes independent of the elevations associated with drusen. Finally, we graded exudative lesions and changes in photoreceptor inner and outer segments. Assignment of Maculopathy Status Histopathologic assessments were graded for three purposes. The first was for for case definition. Using the worst grades for each parameter in the combined foveal and temporal sections, we defined early ARMD as the presence of one large druse (>125 jam in diameter; grade 2) or severe RPE changes (grades 2-4). Eyes with RPE changes also had to have at least one druse (drusen number grade 1 or higher) or continuous basal deposits (grades 2-3). Note that the logical structure of this defini- Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1088 Curcio et al. IOVS, June 1998, Vol. 39, No. 7 TABLE 2. Histopathology Grades Grades Lesion Total basal deposits Size of largest druse Number of drusen RPE morphologic description Detachment Choroidal neovascularization Photoreceptor outer segments Photoreceptor inner segments 0 1 2 3 4 None <66 ixm None Uniform None None Normal Normal Patchy 63-125 jam Thin continuous >125 /mi >3 Heaped or sloughed Retina Thick continuous na na na na na Anterior migration Atrophy na na na na na na na na 1-3 Nonuniform RPE Present Shortened Broadened na Missing Missing na, not applicable; RPE, retinal pigmental epithelium. tion resembles that used by epidemiologists for fundus grading (Table 1) but differs in several significant ways. First, we used drusen size as a stand-in for drusen type, because the histologic equivalents of epidemiologic soft drusen subclasses are uncertain.13 Although most soft drusen are more than 63 jam in diameter,13 we found in preliminary testing that using 63 /-ini rather than 125 jLim as a size cutoff merely caused us to identify more eyes without photoreceptor degeneration as ARMD cases. Second, epidemiologists grading from stereoscopic color fundus photographs require at least some drusen in eyes with pigmentary changes to distinguish ARMD from other conditions affecting the RPE (Table 1). We also included basal deposits to improve discrimination among RPE lesions,13 because preliminary observations indicated that some of these eyes had significant basal deposits without drusen. The second purpose of the grading system was calibration against existing case definitions. We used grading of histopathologic assessments to assign maculopathy status to the same eyes, using other published definitions (Table i ) . 1 1 1 2 1 4 According to these studies, continuous basal deposits (grade 2-3), numerous drusen (grade 2), severe RPE change (grade 2-4), and photoreceptor degeneration (grade 1-2) meet criteria for the histologic diagnosis of early ARMD. The third purpose of the grading system was validation of postmortem fundus grades. Retinal edema and detachment can appreciably reduce the visibility of posterior pigmented tissues. Our preliminary observations in fresh eyes suggested that these changes had occurred after death and did not worsen markedly with fixation. In addition, choroidal vessels empty after death, making it difficult to assess minor pigmentary variations in the plane of the RPE against the undulating background of pale vessels and dark interstitial tissue. Therefore, applying methods for grading clinical fundus photographs directly to grading preserved donor eyes is unwarranted, given the distinctly different detail visible in the fundus before and after death. Our approach was to adapt WARMGS to the constraints of our material. To determine those constraints empirically, we compared fundus grades for the central subfield with histopathologic assessment of the fovea and fundus grades for the combined temporal inner and outer subfields with temporal histopathologic evaluation in eyes with gradable photographs. We also determined interobserver consistency. Using histopathologic analysis as the standard, we determined the number of true-positives and false-positives and true-negatives and false-negatives for each grader's subfield scores. We considered the scoring of a grossly visible lesion by one grader a false-positive for that grader if the lesion was not seen microscopically. However, we did not consider drusen that were grossly visible to both graders but were not noted in histologic study (n — 4) to be false-positive, because the tissue blocks were not exhaustively sectioned, and it was possible to miss lesions. Finally, we calculated sensitivity and specificity of assigning maculopathy status on the basis of postmortem fundus appearance for histopathologically defined ARMD and nonARMD eyes using standard methods.23 RESULTS Nineteen of 34 eyes were considered to have ARMD by at least one standard (clinical history, histopathologic assessment, or postmortem fundus appearance). In Table 3, findings in 10 eyes that met our histopathologic criteria (cases 1-10) are summarized, plus findings in 9 eyes that met any other criteria (A-I). Table 4 summarizes the number of ARMD cases identified by different criteria, each normalized by the number of eyes that could be evaluated and arranged in order from most restrictive to least restrictive. Approximately one third (27%-33%) of eyes met either our histopathologic criteria, those of Green and Enger,l2 or those of Spraul et al.14 to be classified as affected by early ARMD. A similar proportion (33%) was identified by our fundusgrading criterion (see later description). In contrast, twice as many eyes (46%-5O%) met either the Ramrattan et al. criteria11 or had a history of ARMD or drusen. Within these two broad groups, there was disagreement about individual eyes (Table 3). Clinical Findings and Fundus Appearance Ophthalmic histories were available for 30 patients. The median time of the last ocular examination before death or exenteration was 11.3 months (range, 0-159.7 months). Thirteen eyes (10 men and 3 women; 53-92 years old) had unremarkable maculae. Twelve eyes had clinical indication of ARMD or drusen (Table 3; 7 men and 5 women; 60-86 years old): six with drusen, two with changes in RPE, two with drusen and changes in RPE, and two with nonspecific mention of ARMD. A fluorescein angiogram in one eye (case 5) verified the absence of choroidal neovascularization. Clinical fundus photographs (Fig. 1) were evaluated forfiveeyes with ARMD- drusen history. Three eyes (cases 2, 8, 5) contained mostly soft, distinct drusen, that is, solid, thick drusen of uniform density and Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 ARMD Cases by Current Histopathologic Criteria Other Criteria^ LE* (mo) Lens Scored PhotFA§ Age Sex 60 63 64 M F M 0.0 9.7 na# 20/30 20/25+1 na 2 2 na X/X/- 74 M 23.1 20/40- 3 X/- 74 M 18.7 20/20 2 X/X 74 M 0.0 20/50 3 X/- 75 80 M M 0.6 0.3 20/60ph40 20/40-1 2 0 X/- 83 90 F F 7 na 20/60 na 0 na na na na 2 23.4 1.1 4.1 5.9 na na na 20/2520/60ph50+ 20/100 + 20/40 20/50 na na na 2 0 3 2 3 12.9 20/40 OE VAcc-f Significant Macular History Drusen mild ARMD Dry ARMD No visual complaint as per family Drusen and/or pigment changes Dry ARMD, drusen, pigment clumping Prob ARMD, pigment clump, no drusen Drusen Few drusen, areas of RPE atrophy Giant drusen, ARMD na R B Y Y Y Y Y Y N Y N Y Y Y N Y N Y Y Y Y N Y Y Y Y Y Y Y Y Y Y Y Y Y N N N N N N Y Y Y Y N N Y Y N Y Figures N Y Y N Y ID, 2B, 6D 1A, 3, 6A 2A Y i c , 6C Y IE, 2E, 6E Y Y 6H IB, 2D, 4B,6B Y Y Y Y 2C, 6G 2F, 4A, 6F N N N Y N N N N N N N N N N N N N ses by Other Criteria 65 69 71 73 79 80 81 86 M M F F F M F F 92 M X X na na na Drusen, dry ARMD Drusen Slight ARMD Unremarkable Few RPE changes, dry ARMD changes Unremarkable elated macular degeneration; FA, fluorescein angiogram; OE, orbital exenteration; PCIOL, posterior chamber intraocular lens; RPE, retinal pigment epithelial; Y, yes; N, no ation before death or surgery, y, corrected. OL; cataract: 1, slight; 2, moderate; 3, significant. us photos-fluorescein angiogram. nd Enger12 (histologic examination); R, Ramrattan et al. 11 (histologic examination); S, Spraul and Grossniklaus.14 (histologic examination); B, Beaver Dam Eye Study17 (epi onal criteria 15 (epidemiologic study); A, Alabama ARMD Grading System, postmortem fundus. hy status of fellow eye: Hx, chart; A, Alabama ARMD Grading System, postmortem fundus. le. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1090 Curcio et al. IOVS, June 1998, Vol. 39, No. 7 TABLE 4. Early ARMD Cases Identified by Different Criteria Criteria Gradable Eyes Number of ARMD Cases Spraul et al. Current (histologic) Green and Enger Current (fundus) Clinical history Ramrattan et al. 30 34 34 30 25 34 8 10 11 10 12 17 Percent Affected 26.7 29.4 32.4 33.3 48 50 ARMD, age-related macular degeneration. sharp edges with maximum size between 125 ju-m and 250 /xm. A soft indistinct druse was identified in one eye (case 2) and with less certainty in two other eyes (cases 8 and 5). The eye in case 2 had a questionable drusenoid RPE detachment.13'21 Eyes in cases 2 (Fig. 1A) and 8 (Fig. IB) had increased pigment within the central subneld. The eye in case 1 (Fig. ID) had only soft distinct drusen without RPE changes. The eye in case 6, which showed a distinctive coarse clump of increased pigment and drusen (Fig. IE), was considered a pattern dystrophy. Therefore, four eyes (cases 1, 2, 5, 8) met International criteria for ARMD, and three met BDES criteria (cases 2, 5, 8). Histopathologic Assessment Ten eyes met our histologic criteria for early ARMD (cases 1-10; Table 3; Figs. 2, 3, 4). Eyes met criteria on the basis of foveal disease alone, although ARMD was present in the temporal parafovea. As a group, these eyes had prominent basal deposits (grades 2-3; n = 8; Figs. 2A, 2F), numerous drusen (grade 2; n = 7), intermediate to large drusen (grades 1-2; n = 8; Figs. 2A, 2C; Fig. 3), RPE changes (grade 2-4; n = 6; Figs. 2C, 2D, 2E, 2F, 3B, 4B), and RPE detachments (n = 2). At least mild photoreceptor degeneration (grade 1; inner or outer segments) was present in 9 of 10 eyes (Fig. 4). No eyes had choroidal neovascularization or disciform scars. Seven eyes with diverse changes in the foveal RPE-Bruch's membrane complex, and unique combinations of lesions were agreed on by all maculopathy standards to be early ARMD (Figs. 2, 3; Table 2). The eye in case 2, with drusen present for at least 22 years before death, had a large druse with softening margins located in the fovea24 (Fig. 3). Eyes in cases 4 and 7 had grade 2 basal deposits, grade 2 drusen size, and grade 2-3 RPE changes (Fig. 2A). The eye in case 9 had RPE heaping and atrophy, a serous RPE detachment, large calcified drusen, and little or no basal deposits (Fig. 2C). The eye in case 8 had macrophages in Bruch's membrane, intraretinal migration of pigmented cells, and large drusen (Figs. 2D, 4B). Two eyes had marked RPE involvement without detectable drusen. The eye in case 10 had grade 3 basal deposits (Figs. 2F, 4A) and RPE cells sloughed into the subretinal space (grade 2). The eye in case 6 had a large mound of deposits containing abundant pigmented debris and RPE heaping, migration, and atrophy (Fig. 2E). There was less agreement among standards about the maculopathy status of eyes in cases 1 and 3 (Table 3)- These eyes had large drusen, basal deposits, and mild photoreceptor degeneration, but severe RPE change was absent (Fig. 2B). There was also disagreement about the eye in case 5, which had at least one large druse among numerous smaller ones. Other eyes did not meet our criteria but met those of other investigators (Table 3, donors A-I). Of note were four eyes with clinical history of ARMD or drusen. Eye E had a few depigmented RPE cells that may have been interpreted as drusen.6 Eyes D and H had relatively mild ARMD in the temporal parafovea. Finally, eye F had a small area of RPE heaping and atrophy without significant basal deposits, possibly related to a foveal epiretinal membrane (H. Grossniklaus, personal communication, 1997). Visual Acuity To determine whether ARMD had markedly impaired vision in these eyes, we compared histopathologic diagnoses with best corrected visual acuity at last examination (Fig. 5). Eight eyes with clinical ARMD- drusen history also met our histopathologic criteria. Four eyes with ARMD history that did not meet our criteria were considered non-ARMD and are shown separately in the figure. Snellen acuity for 10 non-ARMD eyes and 6 of 8 ARMD eyes ranged from 20/20 to 20/40, within the range reported in large-population studies. 25 ' 26 Only five eyes had 20/50 vision or worse (three non-ARMD, two ARMD). Poor acuity in three eyes with ARMD-drusen history and mild pathology (Table 3: eyes E, F, and H) was associated with other vision-limiting conditions. Eye E was last examined 1 day after cataract extraction, and eyes F and H had significant cataract. Of two ARMD eyes with vision of 20/50 or worse, the one in case 6 had significant cataract. Therefore, only in the eye in case 9, with 20/60 vision through a posterior chamber intraocular lens, can poor vision be ascribed primarily to ARMD. Postmortem Fundus Appearance Postmortem fundus appearance is shown for eight eyes with early ARMD in Figure 6. Thirty of 34 eyes had gradable photographs. Four of the 26 donor eyes (15%) were ungradable because of postmortem retinal changes. As a group, the more rapidly preserved surgical eyes (Figs. 6B, 6D, 6E, 6H) had clearer retinal tissue than did donor eyes (Figs. 6A, 6C, 6F, 6G) but were nonetheless comparable to the best donor eyes. Numerous drusen are present in most eyes with ARMD (Figs. 6A, 6B, 6C, 6D, 6G, 6H). Particularly distinctive were large irregular drusen in the eye in case 2 (Fig. 6A) and calcified drusen in the one in case 9 (Fig. 6G). Hyperpigmentation of the RPE was present in many eyes (Figs. 6A, 6B, 6E, 6H), usually associated with drusen. Two eyes had pigmentary changes without obvious drusen. The eye in case 6 had a T-shaped clump of hyperpigmented cells flanked by atrophic spots (Fig. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 Grading ARMD Donor Eyes IOVS, June 1998, Vol. 39, No. 7 1091 FIGURE 1. Clinical fundus photographs. All eyes except (E) are considered affected by early age-related macular degeneration (ARMD) according to international criteria because of the presence of soft drusen. The eyes in case 2 (A), case 8 (B), and case 5 (C) are considered affected by ARMD by the Beaver Dam Eye Study criteria because of the presence of increased pigment and soft, indistinct drusen. (A) Case 2, 22 years before death, (B) Case 8, 1 week before orbital exenteration. (C) Case 5, 39 months before death. (D) Case 1, 3 days before surgery. (E) Case 6, 1 day before surgery. 6E). The one in case 10 had fine pigment clumps (Fig. 6F). Hypopigmentation of the RPE was present at the site of the RPE detachment in the eye in case 9 (Fig. 6G). For 30 eyes that were graded and then analyzed histologically, fundus grades were more reliable for eyes with worse maculopathy than for eyes with no or borderline maculopathy. Results for the fovea and temporal parafovea were similar, despite the thicker parafoveal retina. No eyes with large (>125 jam in diameter) or intermediate (63-125 ixm in diameter) drusen were missed by either grader. Agreement on the size of the largest druse in these eyes was excellent. However, the detection of small drusen (<63 /u,m) generated false-negative and false-positive findings. Fine irregularities of foveal RPE pigmentation were occasionally considered small drusen by one grader. Accordingly, agreement between graders was less good for measurements that included small drusen (predominant drusen size, total drusen number, and percentage of drusen coverage). We also could not identify drusen subtypes except for calcified drusen (Fig. 6G). No eye with severe RPE changes (histologic grades 2-4) was missed grossly, but several eyes with normal RPE (grades 0-1) were graded as having small areas of increased pigment by one or both graders. Rather than missing subtle maculopathy, our errors tended in the direc- Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1092 Curcio et al. IOVS, June 1998, Vol. 39, No. 7 2. Histopathologic studies of eyes with early age-related macular degeneration. One-micrometer sections; toluidine blue; scale bar in D, 20 fim. (A) Large druse with grade 2 basal laminar deposit (case 4). (B) Large druse (case 1). (C) Large calcified druse, retinal pigment epithelium (RPE) atrophy, and photoreceptor loss (case 9). (D) Heaping and sloughing and anterior migration of the RPE, basal deposits, and macrophages in Bruch's membrane {arrowhead; case 8). (E) Heaping and sloughing of the RPE with pigmented debris (arrowhead, case 6). (F) Grade 3 basal deposits (case 10). FIGURE tion of overinterpreting normal variation. Given these reliability constraints, we based our fundus criteria for early ARMD on the size of the largest druse and area of increased pigment and imposed a size criterion on the latter to reduce the number of false-positive findings. By choosing eyes that contained at least one druse more than 125 /xm in diameter or an area of pigment clumping 500 jam in diameter within the grid, we identified 9 of the 10 ARMD eyes, as well as 1 non-ARMD eye (Table 3), for a sensitivity of 0.90 and a specificity of 0.95 (Table 5). Case 1 (Fig, 6D) was missed, because its drusen were judged intermediate on gross inspection but were actually more than 125 /xm in diameter when measured in sections. The non-ARMD eye (A, Table 3) had large drusen in the outer temporal subneld that were not sectioned. DISCUSSION To achieve the same goals of objectivity and reprodiicibility that motivated clinical ARMD researchers to rely on standard fundus photographs rather than clinical examinations,6'7 we relied on standard photographs of the postmortem fundus rather than on gross examinations for ARMD studies using donor eyes. A photographic record of fundus appearance before irreversible processing of tissue permits retrospective examination of the macula in the light of subsequent results. Although the gross lesions associated with late ARMD may be more readily detectable in postmortem eyes,5'14 these eyes represent advanced disease. Important contributions to our current understanding of the critical early stages of ARMD have been made by large-scale studies 41220 ' 27 " 29 and careful clinicopathologic correlations on a small number of eyes. 1316 ' 30 Further understanding of the cellular and molecular events initiating ARMD will require biochemical and histochemical analysis of donor eyes with well-defined maculopathy status. Eyes with early ARMD can thus reveal useful information regarding ARMD pathogenesis, yet it is precisely this stage of disease that is least agreed on. The Alabama ARMD Grading System criteria are adequate to identify histopathologically confirmed eyes with early ARMD with 90% sensitivity and 95% specificity, thus permitting rational and standardized study design. Our study eyes were chosen in a highly selective Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 Grading ARMD Donor Eyes IOVS, June 1998, Vol. 39, No. 7 1093 6 FIGURE 4. Photoreceptor degeneration in eyes with age-related macular degeneration. One-micrometer sections; toluidine blue; scale bar in B, 20 /xm. (A) Shortened and missing outer segments and broadened inner segments (case 10). (B) Missing photoreceptors (case 8). 3. Sections through the margin and center of a large druse in the foveal center (case 2). One-micrometer sections; toluidine blue; scale bar in C, 20 /jrnn. (A) Margin of large druse contains pigmented debris, ribbons of basal deposits, and serous fluid, typical of softening drusen. (B) In a transitional zone 0.15 mm inferior to (A), pockets of original druse contents appear (arrowheads). (C) Area 0.05 mm inferior to (B), center of large druse that is representative of other drusen in this eye. 10 FIGURE NonARMD ARMD (clinical & histological) ARMD (clinical only) - 20/100 5 • « 3^ 2 manner, and therefore the proportions of ARMD and nonARMD eyes are not representative of prevalence in the general donor population. Because we found that most decreases in the clarity of the retina and the visibility of underlying pigmented tissues occurred with death and not withfixation,we used eyes obtained 3 hours or less after death. Even among these quickly preserved eyes, however, 35% (2/57) of consecutive eyes were not photographed because of folds in the macula, and 12% (4/33) of eyes that were photographed could not be graded. Nevertheless, our methods could be applied to a wider range of postmortem intervals until fixation, provided that criteria for tissue gradability are enforced. Interobserver reliability for definite maculopathy in postmortem eyes was good, despite some confusion about small drusen and minor pigment variation, similar to clinical fundus grading.7 We set a lower limit of 500 /am on the diameter of RPE hyperpigmentation, because smaller abnormalities tended to be false-positive findings. These errors are likely to decrease in the future as a result of our histologic analysis, permitting us to reduce or eliminate the size criterion, Because only three eyes in our series had confirmed atrophy, we could not assess reliability for its detection. Definitions of ARMD have evolved -with little agreement on the definition of specific lesions or classification.15'31 In 20/200 • O T • - 20/60 O • O •d» TO 1 • T • - 20/40 • •• o - 20/20 ao 100 Age, yr FIGURE 5- Best corrected acuity (minimum angle of resolution [MAR] and Snetlen's chart) at last examination for 30 donors or patients. Eight patients had clinical history of age-related macular degeneration (ARMD) or macular drusen with histopathologic confirmation, 4 had clinical history without histopathologic confirmation, and 18 had history and histopathologic confirmation of normal maculae. Pathologic analysis confirmed that there was no optic nerve involvement in the patients who underwent orbital exenteration. One patient had paracentral visual field loss corresponding to a chronic occipitotemporal lobe infarct revealed by magnetic resonance imaging. In two patients, the last reliable visual acuity before the onset of tumor complications (approximately 2 years before surgery) are plotted. Grades for lens status in eyes more than 50 years old (Table 3) for 8 ARMD patients (2/0/4/2), 4 clinical ARMD patients (1/0/1/2), and 12 non-ARMD patients (0/2/5/3; 3 not recorded) indicate a similar proportion of cataract in ARMD and nonARMD eyes and a higher proportion of significant lens changes in eyes with clinical ARMD history only. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1094 Curcio et al. IOVS, June 1998, Vol. 39, No. 7 6. Maculae in preserved eyes. Clinical fundus photographs for the eyes in (A), (B), (C), (D), (E) are shown in Figure 2 (A, B, C, D, E), Photographs were taken with epi-illumination and transillumination at X5.6 original magnification, except for (A), which was taken with epi-illumination only. (A) Case 2; (B) case 8; (C) case 5; (D) case 1; (E) case 6; (F) case 10; (G) case 9; (H) case 7, FIGURE Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 Grading ARMD Donor Eyes IOVS, June 1998, Vol. 39, No. 7 TABLE 5. Comparison of Postmortem Fundus Appearance and Histopathology Histologically Defined Postmortem Fundus True ARMD True Non-ARMD ARMD Non-ARMD Sensitivity/Specificity 9 1 0.90 1 19 0.95 ARMD, age-related macular degeneration. calibrating our histopathologic ARMD criteria against other standards, we confirmed the prediction that the number of identified cases could range considerably. Nevertheless, the percentage of eyes identified as cases by our criteria were in good overall agreement with those identified by two other studies.1214 The less restrictive logic of the Ramrattan et al. criteria1' identified 50% more cases, mainly by including eyes with numerous small drusen. Notably, the number of eyes with clinical history of ARMD or drusen exceeded the number of histopathologically confirmed ARMD cases by a similar margin. These results underscore the fact, well-recognized in clinical research, that medical records are insufficient to define cases. Therefore, as in clinical ophthalmic research, ARMD cases among donor eyes should be ascertained with independent and objective measurements of maculopathy status, such as histopathology, fundus appearance, or both. Despite these limitations, however, the records we obtained were sufficient for our original purposes—that is, to exclude non-ARMD chofioretinal macular pathology and to determine whether ARMD pathology had seriously reduced vision. Corrected acuity at last examination in 9 of 10 eyes with early ARMD were comparable to those in age-matched non-ARMD eyes. The worst acuities were associated with confounding factors such as cataract. To our knowledge, this represents the first published histopathologic study of eyes for which clinical photographs were graded according to WARMGS. Offiveeyes with gradable photographs, three were considered affected by ARMD by BDES standards because of the presence of soft, indistinct drusen, and in the case of two eyes, increased pigment. Soft, indistinct drusen are thought to indicate high risk for late ARMD.10 Their histologic equivalents are uncertain but are probably caused by differences in drusen size, shape, RPE depigmentation, and perhaps molecular constituents.32"35 A druse type common to these three eyes had sloping margins and membranous contents (preliminary observations).2427'36 Identification of high-risk drusen requires detailed grading and serial section histologic analysis in the same eye. We confirmed that focal hyperpigmentation corresponds to heaped, sloughed, or migrating RPE cells.14 Of note, a distinctive pigmentary figure in the eye in case 6 was thought by WARMGS graders to be a pattern dystrophy37"40 and therefore nonARMD. This finding underscores the fact that without clinical examination and testing of donor family members, it is difficult to distinguish between some hereditary macular. diseases37'41 and ARMD in donor eyes. Despite the distinctly different appearances of the fundus before and after death, we learned lessons that are potentially applicable to clinical fundus grading. Clinical studies have shown that the presence of any large drusen8 or any of a 1095 subtype of soft drusen,10 regardless of drusen number or degree of confluence, indicates an eye at risk for late ARMD. We demonstrated the diversity of ARMD attainable by selecting for only one large druse. In addition, we found that ARMD status was established by foveal disease alone, consistent with clinical studies showing that eyes with lesions less than 1500 jam from the foveal center are at higher risk for late ARMD.42 It is possible that future fundus grading could therefore be restricted to a more central area of the macula. A single definition for early ARMD applicable to fundus appearance and histology is desirable because it would ensure comparable disease stage in case-control studies drawn from different patient populations. As seen in even our small sample, perfect agreement between the two is not attainable because fundus photographs and histologic sections differ in how the macula is sampled and in the precision with which lesions can be measured. In addition to logical inconsistencies pointed out in Table 1, it is also clear that histologic definitions of early ARMD cannot be resolved with clinical definitions if they include lesions not visible in the fundus. These lesions include basal deposits,12'20 a prominent feature with a controversial role in ARMD pathogenesis,43'44 and photoreceptor degeneration, the basis of ARMD-associated visual dysfunction. Other investigators have shown that large drusen13 and RPE hyperpigmentation and hypopigmentation14 serve as markers for basal deposits in the fundus. Our work demonstrates that large drusen and changes in RPE may serve as markers for early photoreceptor degeneration as well. Acknowledgments The authors thank Andy Patrick, Technical Services Director, the Alabama Eye Bank, for timely retrieval of donor eyes; the Montana Eye Bank for one pair of donor eyes; the Eye Foundation Hospital and the Tissue Procurement Program of the UAB Comprehensive Cancer Center (CA13148) for surgical specimens; Cynthia Owsley, of the Clinical Research Unit, Department of Ophthalmology, University of Alabama at Birmingham (National Institutes of Health grant AG04212), for clinical fundus photogniphs and eye examinations for cancer patients; James Keffer for obtaining eye histories from donor families; James O. Powell for consultation on eye disease; Gerald McGwin, Jr., for consultation on data analysis (National Institutes of Health AG04212); and Sarah Ansay, Jane Armstrong, Maria Swift, Jeff Whitehead, Larry Hubbard, and Ronald Klein (EY06594), of the Fundus Photograph Reading Center, Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, for evaluation of clinical fundus photographs. References 1. Leibowitz HM, Maunder LR, Milton RC, et al. The Framingham eye study monograph. Surv Ophthalmol. 1980;24(Suppl):335-6l0. 2. Hope GM, Dawson WW, Engel HM, Ulshafer RJ, Kessler MJ, Sherwood MB. A primate model for age related macular drusen. BrJ Ophthalmol. 1992;76:11-16. 3- Nicolas MG, Fujiki K, Murayama K, et al. Studies on the mechanism of early onset macular degeneration in cynomologous (Macaca fascicularis) monkeys. I. Abnormal concentrations of two proteins in the retina. Exp Eye Res. 1996;62:211-219. 4. van der Schaft TL, Mooy CM, de Bruijn WC, Oron FG, Mulder PGH, de Jong PTVM. Histologic features of the early stages of age-related macular degeneration. Ophthalmology'\ 1992;99:278-286. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/journals/iovs/933206/ on 05/05/2017 1096 Curcio et al. 5. Curcio CA, Medeiros NE, Millican CL. Photoreceptor loss in agerelated macular degeneration. Invest Ophthalmol Vis Sci. 1996; 37:1236-1249. 6. Bressler NM, Bressler SB, West SK, Fine SL, Taylor HR. The grading and prevalence of macular degeneration in Chesapeake Bay watermen. Arch Ophthalmol. 1989; 107:847-852. 7. Klein R, Davis MD, Magli YL, Segal P, Klein BEK, Hubbard L. The Wisconsin Age-Related Maculopathy Grading System. Ophthalmology. 1991;98:1128-1134. 8. Bressler SB, Maguire MG, Bressler NM, Fine SL, Group MPS. Relationship of drusen and abnormalities of the retinal pigment epithelium to the prognosis of neovascular macular degeneration. Arch Ophthalmol. 1990;108:l442-l447. 9. Bressler NM, Munoz B, Maguire MG, et al. Five-year incidence and disappearance of drusen and retinal pigment epithelial abnormalities. Arch Ophthalmology. 1995;113:3Ol-3O8. 10. Klein R, Klein BEK, Jensen SC, Meuer SM. Thefive-yearincidence and progression of age-related maculopathy. Ophthalmology. 1997;104:7-21. 11. Ramrattan RS, van der Schaft TL, Mooy CM, de Bruijn WC, Mulder PGH, de Jong PTVM. Morphometric analysis of Bruch's membrane, the choriocapillaris, and the choroid in aging. Invest Ophthalmol Vis Sci. 1994;35:2857-2864. 12. Green WR, Enger C. Age-related macular degeneration histopathologic studies: the 1992 Lorenz E. Zimmerman Lecture. Ophthalmology. 1993:100:1519-1535. 13. Bressler NM, Silva JC, Bressler SB, Fine SL, Green WR. Clinicopathological correlation of drusen and retinal pigment epithelial abnormalities in age-related macular degeneration. Retina. 1994; 14: 130-142. 14. Spraul CW, Lang GE, Grossniklaus HE. Morphometric analysis of the choroid, Bruch's membrane, and retinal pigment epithelium in eyes with age-related macular degeneration. Invest Ophthalmol Vis Sci. 1996;37:2724-2735. 15. Bird AC, Bressler NM, Chisholm IH, et al. An international classification and grading system for age-related maculopathy and age-related macular degeneration. Surv Ophthalmol. 1995;39:367-374. 16. Sarks JP, Sarks SH, Killingsworth MC. Evolution of geographic atrophy of the retinal pigment epithelium. Eye. 1988;2:552-577. 17. Klein R, Klein BEK, Linton KLP. Prevalence of age-related maculopathy. Ophthalmology. 1992;99:933-943. 18. Vingerling JR, Dielemans I, Hofman A, et al. The prevalence of age-related maculopathy in the Rotterdam study. Ophthalmology. 1995;102:205-210. 19. Mitchell P, Smith W, Attebo K, Wang JJ. Prevalence of age-related maculopathy in Australia. Ophthalmology. 1995;102:l450-l460. 20. Sarks SH. Ageing and degeneration in the macular region: a clinicopathological study. Br J Ophthalmol. 1976;60:324-34l. 21. Pauleikhoff D, Barondes MJ, Minassian D, Chisholm IH, Bird AC. Drusen as risk factors in age-related macular disease. Am J Ophthalmol. 1990; 109:38-43. 22. Loffler KU, Lee WR. Basal linear deposit in the human macula. GraefesArch Clin Exp Ophthalmol. 1986;224:493-501. 23. Hennekens CH, Buring JE. Epidemiology in Medicine. Boston: Little, Brown; 1987. 24. Sarks SH, van Driel D, Maxwell L, Killingsworth M. Softening of dnisen and subretinal neovascularization. Trans Ophthalmol Soc UK. 1980;100:4l4-422. IOVS, June 1998, Vol. 39, No. 7 25. West SK, Munoz B, Rubin GS, et al. Function and visual impairment in a population-based study of older adults: the SEE Project. Invest Ophthalmol Vis Sci. 1997:38:72-82. 26. Klein R, Klein BEK, Lee KE. Changes in visual acuity in a population. Ophthalmology. 1996;103:ll69-1178. 27. Sarks SH. Drusen and their relationship to senile macular degeneration. Aust J Ophthalmol. 1980;8:l 17-130. 28. Green WR, Key SN. Senile macular degeneration: a histopathological study. Trans Am Ophthalmol Soc. 1977;75:180-254. 29- Green WR, Schwartz DM. Aspects histopathologiques. In: Coscas G, eds. Degdnerescences Maculaires Acquises Lie~es a I'Age et Neovaisseaux Sous-Retiniens. Paris: Masson; 1991:90-11930. Sarks JP, Sarks SH, Killingsworth MC. Evolution of soft drusen in age-related macular degeneration. Eye. 1994;8:269-283. 31. Vingerling JR, Klaver CCW, Hofman A, de Jong PTVM. Epidemiology of age-related maculopathy. Epidemiol Rev. 1995;17: 347-360. 32. Farkas TG, Sylvester V, Archer D, Altona M. The histochemistry of drusen. AmJ Ophthalmol. 1971;71:1206-1215. 33. Newsome DA, Hewitt AT, Huh W, Robey PG, Hassell JR. Detection of specific extracellular matrix molecules in drusen, Bruch's membrane, and ciliary body. Am J Ophthalmol. 1987; 104:373-381. 34. Pauleikhoff D, Zuels S, Sheraidah GS, Marshall J, Wessing A, Bird AC. Correlation between biochemical composition and fluorescein binding of deposits in Bruch's membrane. Ophthalmology. 1992; 99:1548-1553. 35. Mullins RF, Johnson LV, Anderson DH, Hageman GS. Characterization of drusen-associated glycoconjugates. Ophthalmology!. 1997; 104:288-294. 36. Green WR, McDonnell PJ, Yeo JH. Pathologic features of senile macular degeneration. Ophthalmology. 1985;92:6l5-627. 37. Marmor MF, McNamara JA. Pattern dystrophy of the retinal pigment epithelium and geographic atrophy of the macula. Am J Ophthalmol. 1996; 122:382-392. 38. Hsieh RC, Fine BS, Lyons JS. Patterned dystrophies of the retinal pigment epithelium. Arch Ophthalmol. 1977;95:429-435. 39. de Jong PTVM, Delleman JW. Pigment epithelial pattern dystrophy. Four different manifestations in a family. Arch Ophthahnol. 1982;100:l4l6-l421. 40. Prensky JG, Bresnick GH. Butterfly-shaped macular dystrophy in four generations. Arch Ophthalmol. 1983:101:1198-1203. 41. Gorin MB, Jackson KE, Ferrell RE, et al. A peripherin/retinal degeneration slow mutation (Pro-210-Arg) associated with macular and peripheral retinal degeneration. Ophthalmology. 1995; 102: 246-255. 42. Group MPS. Risk factors for choroidal neovascularization in the second eye of patients with juxtafoveal or subfoveal choroidal neovascularization secondary to age-related macular degeneration. Arch Ophthalmology. 1997;115:741-747. 43. van der Schaft TL, de Bruijn WC, Mooy CM, Ketelaars DAM, de Jong PTVM. Is basal laminar deposit unique for age-related macular degeneration. Arch Ophthalmol. 1991;109:420-425. 44. Loffler KU, Lee WR. Is basal laminar deposit unique for age-related macular degeneration? Arch Ophthalmol. 1992;110:15-l6. 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