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Clinical Ectopia Lentis P. Gururaj, DNB, Aravind Eye Hospital, Madurai Introduction Ectopia lentis is defined as displacement or malposition of the crystalline lens of the eye. Berryat described the first reported case of lens dislocation in 1749, and Stellwag subsequently coined the term ectopia lentis in 1856 (describing a patient with congenital lens dislocation). Disruption or dysfunction of the zonular fibers of the lens, regardless of cause (trauma or heritable condition) is the underlying pathophysiology of ectopia lentis. The degree of zonular impairment determines the degree of lens displacement. Management of Ectopia lentis continues to be a difficult problem for the general ophthalmologist. Surgery is technically challenging procedure. The correct timing of surgery to prevent amblyopia is not known & what percentage of cases cionni CTR is feasible is also not known. Following lens removal, several options are available. The child can be left aphakic or IOL implantation can be performed. The IOL can be implanted in the anterior chamber, suture fixated to the Iris, sclera fixated or implanted in the bag following cionni CTR implantion. To date, there is no evidence in the literature as to which of these is the best approach for paediatric ectopia lentis. 10-0 polypropylene use is controversial. (because of high risk of spontaneous breakage). Now 9-0 polypropylene is used in all cases. In a paediatric patient with low hyperopic aphakic refraction, any form of sutured IOL implantation is difficult to justify. Keeping all this in mind, our study aimed to understand the clinical profile, management strategies and functional outcome of ectopia lentis. Embryology of lens and zonules Lens placode, the thickened area of surface ectoderm from which the lens develops, is identifiable by 27 days of Gestation (Embryo 4-4.5mm). The lens placode invaginates the sinus below the surface ectoderm to form a lens vesicle, which consists of a single layer of cells covered by a basal lamina. Primary Lens Fibers The cells of the posterior wall of the lens vesicle rapidly elongate and get filled with proteins called crystalline which make them transparent. These elongated transparent cells are known as Primary Lens Fibers. The nuclei of the lens fibers are present more anteriorly within the cells to form a line cortex forward called the nuclear bow. The primary lens fibers are formed upto 3rd month of gestation and are presented as the compact core of the lens, known as embryonic nucleus. Secondary Lens Fibers The equatorial cells of the anterior lens epithelium remain active throughout the life and form the so called secondary lens fibers. Depending upon the period of development the secondary lens fibers are named as below: - Fetal nucleus refers to secondary lens fibers from 3rd to 8th month of gestation. - Infantile nucleus refers to secondary lens fibers formed during the last week of fetal life to puberty. - Adult nucleus is formed by the secondary lens fibers formed after the puberty. - Cortex consists of the recently formed superficial secondary lens fibers. The Lens Zonules They develop from the neuroectoderm in the ciliary region. The earliest fibers of the zonular apparatus are a continuation of the internal limiting membrane that thickness over the nonpigmented epithelium of the developing ciliary processes. They begin to develop at about 10th week of gestation (45 mm stage). Later, 2 zonular fibers are increased in number, strength and coarseness. By the 5th month of gestation, the zonules reach the lens and merge with both the anterior and posterior capsules. The Anatomy of Ciliary Zonules The ciliary zonules (zonules of zinn or suspensory ligaments of lens) consist essentially of a series of fibers which run from the ciliary body and fuse into the outer layer of the lens capsule around the equatorial zone. Thus, they hold the lens in position and enable the ciliary muscle to act on it. Structure The zonular fibers are transparent, stiff and not elastic. Each zonular fibre has a diameter of about 0.35 to 1.0µ. It is composed of micro fibrils with a diameter varying from 8-40nm. Zonular fibres are composed of glycoproteins and mucopolysaccharides and are similar in structure to the micro fibrils of the elastic fibers. Their susceptibility to hydrolysis by a-chymotrypsin has been used to advangage in intracapsular cataract surgery. Structurally, three different types of zonular fibres have been described. - First type fibres. These are thick, about 1µ in diameter, wavy and usually lie near the vitreous from 3rd to 8th month of gestation. - Second type fibres. These are thin and flat. - Third type fibres. These are very fine and run a circular course. The fibrils are composed of a non collagenous glycoprotein containing O and N-linked oligosaccharides, which explains their positive histochemical reaction to PAS stain. The zonular fibers are strongly immunoreactive for fibrillin. The fibrils resemble elastin in size, tubular structure, cross reactivity and amino acid profile. Gross Appearance Grossly, the ciliary zonules form a complete ring of fibres, which extend from ciliary body to the lens equator circumferentially. On cut section the ciliary zonules appear to be arranged in a triangular form. The base of the triangle is towards the equator of the lens and apex towards the ciliary AECS Illumination body. The space between the triangle is filled with the zonular fibres except for a circumferential space around the equator of the lens between anterior and posterior zonular fibres – the canal of Hannover. Arrangement of zonular fibres 1. Main fibres of the ciliary zonules: a. Orbiculo posterior capsular fibers b. Orbiculo anterior capsular fibers c. Cilio posterior capsular fibers d. Cilio equatorial fibers 2. Auxillary fibers: Pathophysiology Marfan’s Syndrome Mutations in the gene for fibrillin-1 (FBN 1) result in the connective tissue disorder Marfan's Syndrome as well as “simple” Ectopia lentis. FBNI has been mapped to chromosome 15 q 21.1 micro fibril abnormalities have been shown to lie behind the spectrum of diseases produced by FBNI mutations, collectively termed fibrillinopathies. They range from the severe condition neonatal Marfan's Syndrome (usually fatal by age 2) to simple ectopia lentis which is not associated with systemic disease. Zonular fibers are fewer in number, thin, stretched and irregular in diameter. They are also inelastic & more easily broken than normal fibers. The insertion and ultra structure of Zonular fibers attached to the lens capsule is also abnormal. The micro fibrils of the fibers are loosely arranged and disorganized. They exhibit fragmentation and interbead periodicity. It was thought that reduced synthesis of fibrillin combined with proteolytic degradation of micro fibrils accounts for the variable and occasionally progressive nature of some of the clinical manifestations of marfan syndrome. Fibrillin is a glycoprotein secreted by fibroblasts that aggregate either alone or in conjunction with other proteins to form a micro fibrillar network in extra cellular matrix. The micro fibrillar fibers serve as scaffolding for deposition of elastin and Vol. XIV, No.4, October - December 2014 are considered integral components of elastic elements. Although micro fibrillar structures are widely distributed, they are particularly abundant in the Aorto, in ligaments and in the ciliary zonules that support the lens. Histopathology Eyes from patients with Marfan's Syndrome are often markedly enlarged and show poor development of the iris dilator muscle, hypopigmentation or iris pigment epithelium and elongation of ciliary processes. The bundles of zonular fibrils are thin, scanty and poorly aggregated. Homocystinuria It is an autosomal recessive disorder that classically results from a deficiency of cystathionine beta synthase. Hypothetically the deficiency of cystathionine beta synthase could decrease the availability of cysteine for incorporation into the cysteine rich zonular fibrils. Reduced cross linking between sulfahydryl groups could lead to fragmentation and weakening of the zonules. Histopathologically the zonular fibers have an abnormal porous sponge like appearance on scanning electron microscopy, reflecting their composition of short disoriented fibrils. Weill – Marchesani Syndrome Microspherophakia, the classical lenticular finding in patients with Weill – Marchesani Syndrome is an inherited disorder of connective tissue of uncertain cause. The volume of the lens is reduced by 25 – 40%. Thus the abnormal morphology of the lens cannot be explained by loss of zonular traction. Spherophakia & Microspherophakia The lens typically appears smaller & more spheric in configuration when there is partial or total aplasia of the zonule and when the zonular fibers fail to exert sufficient traction on the lens capsule. Sulfite Oxidase Deficiency Sulfite oxidase is a mitochondrial enzyme that is necessary for the final degradation of sulfur – 3 containing aminoacids by oxidation of sulfite to sulfate. Lens dislocation probably occurs because disulfide linkage are important intramolecular (and possibly intermolecular) bounds in the glycoprotein fibrillin, a major constituent of zonular fibers. Clinical Features The most common ocular manifestation of ectopia lentis is reduction in visual acuity, most often due to high lenticular myopia. The amount of visual disturbance varies with type & degree of displacement and the presence of associated abnormalities. Four clinical grades of ectopia lentis are defined by Traboulsi as minimal mild, moderate & total (dislocation)1. Minimal subluxation of a lens may cause no visual symptoms but when the zonules are disrupted causing increased curvature of the lens the result may be lenticular myopia and astigmatism. Ametropic amblyopia produced by subluxated lens has far reaching consequences including glaucoma or retinal detachment. Mono ocular diplopia and photophobia may be present in some. Prevalence of ectopia lentis in general population is not known. The visual outcome with various modalities of treatment is not clearly elucidated. Appropriate refractive correction is often difficult. Surgical indications & techniques keep changing in each decade. Systemic & ocular evaluation is necessary to establish the appropriate prophylactic measures. Ectopia lentis continues to be a diagnostic & therapeutic challenge for most ophthalmologists. Patients with ectopia lentis may be followed for many years without significant ocular problems. However ocular complications associated with displacement of the lens are commonly serious2. The associated abnormalities include amblyopia, uveitis, glaucoma, cataract formation and retinal detachment. Ectopia of lens may cause visual symptoms that vary in severity, depending on the position 4 of the lens. The lens may remain in its normal central position, dislocated slightly backwards with minimal refractive error. Lenticular myopia may result from increased curvature because of relaxation or poor complement of the zonules. A displaced lens may be tilted, causing significant myopi and astigmatism which are difficult to correct optically. If the lens is so much displaced that it occupies only a portion of the puplliary area, an aphakic correction is necessary. Therefore early and careful refraction is necessary to avoid the occurrence of amblyopia2. Uveitis in ectopia lentis may occur by two different mechanisms. Iridocyclitis may occur due to contact irritation between the iris and ciliary body3. This type of uveitis is often acute, temporary and recurrent and usually responsive to topical steroids. A posterior displacement is usually well tolerated for years provided the lens capsule is not permeable or rupture, allowing lens protein to escape. If this occurs, a phacolytic uvetis with or without a secondary glaucoma might result, requiring a lens extraction. Glaucoma is a serious and common complication of ectopia lentis. The mechanism of glaucoma varies greatly in these eyes. Glaucoma may result from outflow obstruction due to chronic inflammatory cells from lens – induced uveitis, macrophages from a phacolytic glaucoma etc. It may also occur from pupillary block as described in Weill Marchsani syndrome, or by displacement of the lens into the anterior chamber2. Iridectomy is often the treatment of choice; it can prevent or cure the puplillary block glaucoma and simultaneously provide a clear optical area. Although the lens in ectopia lentis may clears for many years, the gradual development of cataract is frequent. The lens opacity may be partial or complete with eventual Morgagnian changes if it becomes totally displaced posteriorly into the vitreous2. Besides causing a visual disturbance a hypermature cataract may also be responsible for phacolytic glaucoma. AECS Illumination Retinal detachment is common and often phacolytic complications occur in the eye with ectopia lentis. They have been reported spontaneously in cases of congenital displacements of lens regardless of surgery4. Jensen and Cross have described retinal detachments in the Marfan's Syndrome and homocystinuria only in eyes with aphakia or ectopia lentis5. However they found no significant difference in the frequency of retinal detachment before and after lens surgery. Treatment of retinal detachment is often difficult because the displaced lens may interfere with visualization of areas of degeneration or tears responsible for the condition. Jarrett found that of retinal detachments in a series of 166 cases of ectopia lentis, only 14 were successfully repaired6. Classification Non – Traumatic subluxation of lens may occur in or in association with systemic and ocular disorders. According to Nelson LB, Maumenee IH et al, Ectopia lentis can be classified as A. Genetic Ectopia lentis without systemic manifestation 1. Simple ectopia lentis. 2. Ectopia lentis Et pupillae B. Systemic disorders associated with ectopia lentis i. Systemic disorders with commonly associated ectopia lentis - Marfans syndrome - Homocystinuria - Weill Marchesani syndrome - Hyperlysinemia - Sulfite oxidize deficiency ii. Systemic disorders with rarely associated ectopia lentis - Ehlers – Danlos syndrome - Crouzon disease - Refsum syndrome - Kniest syndrome - Mandibulofacial dysostosis - Sturge – Weber syndrome Vol. XIV, No.4, October - December 2014 - Conradi syndrome - Pfaundler syndrome - Pierre syndrome - Wildervanck syndrome - Sprengel deformity C. Ocular disorders with ectopia lentis without hereditary predisposition. Other ocular conditions have been reported to occur with ectopia lentis. The most common is ocular trauma, which was the cause of ectopia lentis in 53% of cases in one series. Other ocular abnormalities include retinitis pigmentosa, persistant papillary membrane, aniridia, Reiger’s anomaly, megalo cornea, blepharoptosis & high myopia as well as congenital glaucoma. A. Genetic Ectopia Lentis without systemic Manifestation 1. Simple Ectopia Lentis Simple ectopia lentis occurs either as a congenital disorder or as a spontaneous disorder of the late onset type. Both are inherited in the majority of cases as autosomal dominant without associated systemic abnormalities. Recessive inheritance is rare, usually occurring in families in which consanguinity has been documented7,8. The ocular anomaly in ectopia lentis is usually manifested as bilateral symmetrical, upward & temporal dislocation of the lens. Occasionally the degree of displacement varies considerably between the two eyes. Some of the patients may have spherophakia & lenticular myopia. Spontaneous late subluxation of lenses occur in patients between the ages of 20 and 65 years, There is often marked irregularity & degeneration of the zonular fibers with subluxation of lens inferiorly. Herniation of vitreous associated with zonular degeneration occurs through the zonular defect into the anterior chamber. Both types of ectopia lentis may be associated with cataracts & retinal detachment. Glaucoma usually occurs in the spontaneous late subluxation type rather than the congenital type9. Seland & co-workers described the changes in the zonular fibers from a 5 patient with normal, it was completely devoid of zonular fibers in most of the areas. The remaining capsular attachments were under developed. 2. Ectopia Lentis ET Pupillae Ectopia lentis ET pupillae is a rare congenital disorder in which there are combined anamoly of the lens with pupillary displacement. In two studies in which Ectopia lentis occurred without systemic anomalies, 81 - 93 % had simple ectopia lentis & 7 – 19 % had ectopia lentis ET pupillae11,12. The pupils are characteristically oval or slit shaped, ectopia and they dilate poorly10. The condition is frequently bilateral but asymmetrical. The lenses & pupil are diplaced in the opposite direction from each other. Microspherophakia has been demonstrated histo pathologically13. Marked trans – illumination defects of the iris periphery have been reported in six patients with ectopia lentis Et papillae14. The marfans syndrome in which ectopia lentis occurs commonly, the iris Transillumination defects has been documented clinically 15. They may also have high axial myopia & large cornea16. As with simple ectopia lentis cataract formation, glaucoma, & retinal detachment can occur. Ectopia of lens & pupil follow a recessive mode of inheritance. How ever there has been one report suggesting a dominant in heritance. Consanguinity is frequently reported. B. Systemic Disorders associated with Ectopia Lentis Ectopia lentis may also occur as a common manifestation of systemic hereditary disorders, including marfans syndrome, homocystinuria, Weill Marchesani Syndrome, hyperlysinemia & sulfite oxidize deficiency. 1. Marfan Syndrome The prevalence of Marfan syndrome is 4-6 / 100000 people without racial or ethnic predilections. It is an autosomal dominant condition with variable expressivity. The first descripition of a patient with Marfans syndrome was probably made by elakanoh Williams. He described several members 6 of a family as having upwardly dislocated lenses & generalized loose jointedness. The characteristic features include skeletal cardiovascular & ocular anomalies. Approximately 15% of the cases have no family history and are presumably derived factor in the occurrence of the new mutation. The basic defect in marfans syndrome is not known still. Since hydroxyl proline is an amino acid unique to collagen, these findings suggest a primary defect involving collagen. The increased hydroxyproline excretion may indicate increase amount & a rapid rate of evidence of soluble collagen. Biochemical evaluation has provided evidence that an increase in soluble collagen is due to the defect in the synthetics of type 1 collagen resulting from qualitative & generative changes of the alpha 2 chain. The early cross – links of collagen require alpha 2 chain. The alteration of this results in increased collagen solubility & decreased collagen linking thus an overall reduction in tensile strength. A low content of type – I collagen in the media & adventitia of aorta results in a reduction of its strength which is necessary to withstand the pulsating blood pressure from the heart. As a result the aorta expands & dilates leading to gradual development of an aneurism. Recently reduced tissue lends of hydroxy lysinenor leuine (skin) & 3 hydrozy pyridonium (aorta) were demonstrated in patients with Marfans Syndrome. These abnormalities may result in a misalignment of some of the collagen fibrils involving the alpha – 2 chain causing a disturbance in the specific inter molecular cross - linking during the organization of type. 1 : 111 collagen. Skeletal Manifestations Abnormalities of the skeletal system include excessive height caused by increased length of distal limbs (arachnodactly), loose jointedness, scoliosis, and anterior chest deformities. The skeletal proportions demonstrate an increased arm AECS Illumination span in relation to body height and an elongated lower segment (pubis to sole) compared to upper segment (pubis to vertex)17. The absolute height is not as important as the patients relative height, given the family background. These patients tend to be the tallest in their families. Scoliosis is generally severe and the most disabling complication. It often worsens during the adolescent growth spurt. Attempts have been made to shorten this growth spurt and thereby reduce the severity of the scoliosis. Cardiovascular Manifestations The major cardiovascular complications of aortic aneurysm and floppy mitral valve were described as early as 1943. The vascular tissues involved are those under high vasodynamic stress such as ascending aorta and the mitral valves. The aortic dilatation usually begins at the base and may be progressive. The average life expectancy is halved in Marfan ‘s syndrome. In over 95 % of cases in which a cause of death can be established, a cardiovascular problem is at fault 18 . An echocardiogram should be obtained annually. If aortic dilatation is demonstrated prophylactic propranolol is recommended to reduce myocardial contractility in an attempt to stay progression of aortic dialatation and to prevent acute dissection of aorta. Although the initial trials of propranolol treatment were disappointing new randomized trails have begun. Improved prosthesis and surgical techniques have lowered the morbidity and mortality. Patients with Marfan's Syndrome are at an increased risk for developing endocarditis and should receive antibiotic prophylaxis with dental or surgical procedures. It is recommended by some investigators that patients should not participate in contact sports, isometric exercises, and weight lifting. Since there is an increased risk of vascular rupture during and shortly after pregnancy, women with echocardiographic evidence of aortic dilatation are advised against pregnancy. Vol. XIV, No.4, October - December 2014 Ocular Manifestations An appearance of enophthalmos, especially in severely affected children, may be caused by reduced retrobulbar fat. Many patients present with a facial myopathic appearance as a result of reduced subcutaneous fat, flat malar areas, hypoplastic facial muscle areas and some degree of frontal bossing. In the young age group. reduced visual acuity often resuts from delayed and inadequate refraction with the inevitable development of amblyopia, which is often bilateral. Among the Marfan's Syndrome patients there is a much high incidence of refractive errors, than is found in the normal population. Moderate to high myopia is commonly seen. The corneal diameter may be increased giving the appearance of megalocornea Iris morphology is often striking. The anterior Iris surface is homogeneous with reduced number of circumferential ridges, furrows & crypts; thus it has a smooth velvety appearance. Iris transillumination defects are more marked at its base and occurs in approximately 10% of the patients. Commonly pupil is miotic & difficult to dilate, occasionally pupil is eccentric. The presence of angle anomalies like bridging pectinate strands, In conspicuous Schwalbe's line, irregularity & fraying of the iris root – have been described. Ectopia lentis occurs in 50 – 80% of patients with Marfan's Syndrome. It is almost always bilateral & symmetrical. Usually the amount of dislocation is stable from early childhood. The direction is most commonly superotemporal. The lens may be slightly displaced backwards or vertically & horizontally. Myopic changes & retinal detachments are two retinal findings in Marfan's Syndrome patients. The peripheral retinal changes include, Lattice degeneration & retinal holes. In eye with ectopia lens, retinal detachments have occurred both spontaneously & following intraocular surgeries. 7 The mean axial length measurements for Marfan's Syndrome patients without ectopia lentis was 39 mm & for those with dislocated, 25.06 mm. No patients with a normal axial length developed a spontaneous detachment. Histopathological studies of eye with Marfan's Syndrome patients have shown hypopigmentation of the posterior iris pigment epithelial layer. The sparsely developed dilator muscle seems to account for poor dilatation of the pupil. Table 1: Ocular Manifestation of Marfan’s syndrome Refractive errors Ectopia lentis Megalocornea Retinal detachment Iris transillumination Higher axial lengths Angle abnormalities The zonular & ciliary epithelium may appear normal by light microscopy. However on scan electron microscopy widespread separation of the zonular fibers into a fan of filaments with attenuation towards the lens capsule has been demonstrated. 2. Homocystinuria Homocystinuria is a disease of methionine metabolisim. It is due to a deficiency of the enzyme cystathoionine synthase. Affected patients have elevated blood levels of homocystine and methionine, and will also have amino aciduria (i.e. homocystine). The prevalence of this disorder is 1 out of 200, 000 births. Like Marfan’s it affects the ocular, cardiovascular and skeletal systems. Ocular The ocular abnormalities do not clearly differentiate homocystinuria from Marfan's Syndrome. Ectopia lentis, myopia, retinal detachment, and secondary glaucoma occur in both. Mckusick suggested that lenses are most likely to be displaced upwards in Marfan's and downward in homocystinuria. In contradistinction to Marfan's Syndrome, the zonules are markedly abnormal; the lens cannot accommodate. In addition, approximately one – third of the lenses are eventually completely 8 dislocated into the vitreous or anterior chamber. In marfan’s the subluxation is relatively stable and complete subluxation rarely occurs. Marfan’s dislocation is usually symmetrical and occurs in approximately 90% of patients. Anomalies of the iridocorneal angle have not been described in homocystinuria and may be unique to Marfan’s. Systemic / Cardiovascular The cardiovascular complications are secondary to thrombosis and occlusion, mainly of medium sized arteries and venis. Cerebrovascular thrombosis, myocardial infraction, pulmonary emboli, intermittent claudication and even death at a relatively young age often result. Anesthesia holds a higher risk for patients with homocystinuria because of the possibility of thromboembolic disease. Skeletal Arachnodactyly to the degree seen in Marfan’s is unusual ; however, scoliosis, pectus excacavatum, and joint laxity are seen. Hernias have been described with homocystinuria as well. Patients with homocystinuria are often tall with a malar flush and light colored hair. Mental retardation is frequently present with this condition (in contract to Marfan’s), but it is not an invariable manifestation. Infants may fail to thrive and may be developmentally delayed. 3.Weill – Marchesani Syndrome (Spherophakia – Brachymorphia) Weill – Marchesani syndrome is a rare disease, with unclear inheritance patterns, Most cases are felt to be autosomal recessive; however, autosomal dominant cases have reported. Both sexes are affected equally. Ocular and skeletal abnormalities are characteristic of this disorder. Ocular The lens in Weill- Marchesani is microspherophakic, being typical small and round. The small steep lens results in lenticular myopia. Subluxation occurs in virtually 100 % of cases with over 90% progressing to dislocation by adulthood. Upon dislocation the AECS Illumination lens shifts anteriorly, which results in papillary block glaucoma in approximately 80% of cases. Acute bilateral papillary block and secondary angle closure after papillary dilatation have been reported as the presenting sign in a patient with previously undiagnosed Weill – Marchesani syndrome. The typical skeletal findings of brachymorphia may be subtle, so suspect Marchesani syndrome in children who present with unilateral or bilateral angle pupillary block glaucoma. Not infrequently the lens will completely dislocate into the anterior chamber19. Skeletal Weill - Marchesani Syndrome includes systemic findings of brachiocephaly, short build, broad thorax, brachiodactyly and hypo – extendible joints. In cases where the diagnosis is in questions roentgenographic measurements of the hands are helpful. 4. Spherophakia Spherophakia is a condition where the lens diameter is relatively small; however, there is increased lens thickness. The lens curvature is quite steep and therefore these patients have lenticular myopia. Spherophakia can occur as an isolated anomaly or be in association with the Weill Marchesani Syndrome. 5. Sulfite Oxidase Deficiency Sulfite oxidase deficiency is an extremely rare metabolic disorder. Sulfite is an important intermediary compound in the metabolic pathway from sulfur amino acids to sulfate. In sulfite oxidase deficiency, sulfite cannot be converted into sulfate; hence increased amounts of its metabolities are excreted in the urine. Systemic Patients with sulfite oxidase deficiency may present with hemiplegia progressive choreoathetoid movements, and / or seizures in addition to dislocated lens. The neuropathology reveals atrophic cortical gyri, which is most severe in the parital area and less marked in the frontal area20. Vol. XIV, No.4, October - December 2014 9 Reference: 1. Traboulsi EI. Genetic Diseases of the eye : 1998,607 2. Nelson LB. Maumenee IH. Ectopia lentis. Surv Ophthalmol 1982 : 27 : 143 -60 3. Nirankhari MS. Chaddah MR.Displaced Lens. Am J Ophthalmol 63 : 1719 – 1723, 1967 4. Chandler PA. Choice of treatment in dislocation of lens. Arch Ophthalmol 71 : 765 – 786, 1964. 5. Jphnson RL. Charteris DG. Horgan SE. Cooling RJ, Combained pars plana vitrectomy and sutured posterior chamber implant. Arch of Ophthalmol 118 (7) : 905 – 910, 2000. 6. Jarret WH, Dislocation of lens : a study of 166 hospitalized cases, Arch Ophthalmol 78 : 289 – 296, 1967. 7. Fails AF. Cotterman CW. Genetic studies on ectopia lentis. Arch Ophthalmol 30 : 610 – 620, 1943. 8. Callahan A. Aniridia with ectopia lentis and secondary glaucoma. Genetic pathologic and surgical considerations. Am J Ophthalmol 32 : 28 – 40, 1949. 9. Jensen AD. Cross HE. Ocular complications in Weill Marchesani syndrome. Am J. Ophthalmol 77 : 261 – 269, 1974. 10.Cross HE : Ectopia lentis et pupillae. Am J Ophthalmol 88 : 381 – 184, 1979. 11.Clark CC. Ectopia lentis a pathologic and clinical study. Arch Ophthalmol 21 : 124 – 153, 1939. 12. Lund A, stontoft F. Congenital ectopia lentis. Acta Ophthalmol 29; 33 – 48, 1950 13.Luebbers JA, Goldberg MF. Herbst R. Haatenbauer J. Maumenee AE. Iris trans illumination and variable expression in ectopia lentis. 14.Larsen JS : The Sagittal Growth of the Eye. Ultrasonic measurement of the axial length of the eye from birth to puberty. Acta Ophthalmol 49; 873 – 886, 1971. 15.Maumenee IH. The Eye in Marfan's Syndrome. Trans am Ophthalmol Soc 79: 684 – 73, 1981. 16.Fuchs J : Marfan's Syndrome and other systemic disorders with congenital ectopia lentis – A Danish National Survey, Acta Pediatric 86 (9): 947 – 952, 1997. 17.Pyerits RE and MC Kuisk VA. Marfan’s Syndrome – diagnosis and management. N. Eng J Med. 300 : 772 – 777, 1979. 18.Murdoch JL. Waler BA, Mc Kusick VA. Paternal age effects on the occurrence of new mutatons for the Marfan’s syndrome. Ann Hum Genetics 35 : 331 – 336, 1972. 19.Nelson LB, Calhoun JH Simon JW & Harley RD : Progression of Congenital anterior polar cataracts in childhood Arch. Ophthalmol 103 : 1842, 1985. 20.Rosenblum WI : Neuro pathologic charges in a case of Sulfite oxidase deficiency Neur 18: 1187 – 1196, 1968.