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I. Case History
a. Pt demographics: 72 year old Caucasian female
b. Chief complaint: This pt presented on 8/24/15 for her yearly comprehensive
examination complaining of increased difficulty reading with correction OU. The
pt stated distance vision was reduced, but stable to previous exams. She stated
that her vision is slightly better at night compared to during the daytime. She
also complained of longstanding photophobia and difficulty distinguishing colors.
c. Ocular, medical history:
i. Diagnosed with Rod Cone Dystrophy in 2005 by another provider.
1. Pt has had difficulty with color vision, photophobia, and visual
acuity for approximately 40-50 years.
2. Testing done by previous provider: Color vision and
electroretinography testing with abnormal results. IVFA was also
performed.
ii. Cataract extraction without complications OU in 2014.
iii. Last comprehensive eye examination: 7/30/14
1. Rod Cone Dystrophy with best corrected visual acuities of 20/400
OD, 20/80 OS. The condition was stable to the previous
examination.
iv. Last low vision exam: 8/28/14
1. Pt has received multiple hand-held and stand magnifiers, solar
shields and color identifier in the past.
v. Family ocular history:
1. Blindness - father, 6th decade, unknown etiology
2. Glaucoma - mother and brother
vi. Medical: Hyperlipidemia, coronary artery disease, hypothyroidism,
bladder cancer, depression, insomnia, mood disorder, GERD
d. Medications:
i. Systemic: Albuterol, levothyroxine, nicotine chewing gum, nitrofurantoin,
omeprazole, oxybutynin chloride, sertraline, simvastatin, ziprasidone HCL
ii. Ocular: artificial tears PRN OU, lubricating ointment QHS OU
II. Pertinent Findings
a. Clinical
i. Visual acuity cc: 20/400 OD, 20/80- OS
1. Pinhole: No Improvement OD, 20/80+ OS
ii. EOMs: Full (-)pain (-)diplopia OU
iii. CVF: Full to finger count OD/OS
iv. Pupils: PERRLA (-)APD OU
v. Refraction:
1. Subjective Distance:
a. OD: plano-0.25x065 20/400
b. OS: -0.75-0.75x090 20/802. Subjective Near: (pt accepted trial frame)
a. OD: +8.00-0.25x065 20/400 @ 10cm
b. OS: +7.25-0.75x090 20/40- @ 10 cm
vi. Anterior segment: Unremarkable
vii. Goldmann intraocular pressure: 16/16 @ 0956
viii. Dilated fundus examination:
1. Lens: PCIOL centered and clear OU
2. ONH: 0.25 C/D with temporal pallor OU
3. Macula: pigment mottling with mild RPE atrophy OU
4. Post Pole: scattered small and medium hard drusen, few pigment
clumps OU
5. Periphery: fleck-like pigment clumping 360 OU
ix. Macular Cube OCT: Decreased foveal thickness and exaggerated contour
due to rod cone dystrophy, but stable to previous macular OCT OU.
1. Central thickness: 143 OD, 154 OS
x. Fundus Photos taken OU
III. Differential Diagnosis
a. Primary/leading
i. Rod Cone Dystrophy
b. Others:
i. Stargardt Disease
1. This is typically an autosomal recessive condition characterized by
progressive decline of central vision with variable macular signs.
2. Signs: There are many variations to the appearance of the fundus
in this condition. A normal macular appearance early in the
disease process may be observed. Development of macular signs
later on include pigment mottling, beaten bronze appearance,
geographic atrophy which may appear in a bulls-eye pattern, or
bilateral yellow-white lesions at the RPE level.
a. The most typical finding is pisciform pigment flecks
scattered throughout the posterior pole or extending into
the mid-periphery.
b. Vessels are usually not attenuated. Temporal optic nerve
pallor can occur in more advanced cases.
3. Symptoms: Onset of progressive decrease in central vision in the
first or second decade. Photophobia is rare, though glare may be
bothersome for some pts. A mild red/green color deficiency may
be observed early on in the disease process which progresses in
severity later on. A blue/yellow defect may be apparent later on
as well. Central scotomas may be present. Peripheral vision is not
affected (Kanski, 2011).
4. Testing: Multifocal ERG showed significantly abnormal macular
findings in over 95% of pts, even when no macular signs were
visible and visual acuity was still relatively good. However,
peripheral ERG findings were normal. EOG may be normal or
subnormal in advanced cases. While electrodiagnostic testing may
not help differentiate Stargarts Disease from other macular
dystrophies, fluorescein angiography is crucial in diagnosis.
Fluorescein angiography will show an absence of choroidal
fluorescence due to blockage by accumulation of lipids in the RPE
cells. This is known as “dark or silent choroid”. Hyperfluorescence
may be observed in areas of foveal atrophy (Alexander, 2002).
5. Summary: The pt presented did not have a beaten bronze fundus
appearance, geographic atrophy, or yellow white lesions typical of
this disease. Previous IVFA testing from another provider did not
show “dark” or “silent” choroid.
ii. Central Areolar Choroidal Dystrophy
1. This condition is reported most often as sporadic, but autosomal
dominant and autosomal recessive variations are possible. Pt’s
with this condition present with progressive decrease in central
vision from the fourth to fifth decade.
2. Signs: Early in the disease process, symmetric bilateral RPE
mottling within the macula can be observed. This progresses to
sharply outlined RPE and choriocapillaris atrophy. The area of
atrophy can enlarge, but usually remains confined to the fovea
and surrounding macula. This area can appear excavated on
fundoscopy. Optic disc atrophy, vessel attenuation, and rare
pigment clumping may also be observed.
3. Symptoms: Pt’s will have progressive decline in visual acuity to
20/200 or worse. Central scotomas may also be present. Pt’s may
have reduced sensitivity to red light (pseudo-protanomaly) early
on. This color defect will progress to full red/green or blue/yellow
defects with time. Pt’s will not experience photophobia, night
blindness, or peripheral visual field loss. Progressive hearing loss is
also associated with this condition.
4. Testing: Fluorescein Angiography may show hyperfluorescence of
atrophic areas early in the disease with eventual loss of
choriocapillaris flow without leakage. ERG and EOG will be
normal, though pattern ERG and VEP will be abnormal even early
on in the disease process (Alexander, 2002).
5. Summary: The pt presented had already advanced past the early
stages of her ocular disease and did not show the obvious RPE and
choriocapillaris atrophy typical of this condition. She also is
photophobic.
iii. Benign Concentric Annular Macular Dystrophy
1. This is a rare autosomal dominant condition which presents with
an adult onset of mildly decreased central vision.
2. Signs include: Bulls-eye maculopathy, vessel attenuation, and
paracentral ring scotoma on visual field testing. There is no optic
nerve atrophy in this condition.
3. Symptoms: Mildly reduced visual acuity is typical. In rare cases
this may progress to more significantly reduced acuity, nyctalopia
and blue/yellow color vision defects with pseudoprotanomaly.
Pt’s will not be photophobic.
4. Testing: ERG testing reveals photoreceptor dysfunction with slight
predominance of rod dysfunction. EOG is subnormal early in the
disease with progressive decline later on (Hamel, 2007).
5. Summary: The pt presented had more severe decrease in vision
than is typically found with this condition. Optic atrophy OU was
also observed which is not present in pts with this condition.
iv. Rod monochromatism
1. This is an autosomal recessive disorder which causes reduction in
visual acuity and color vision defects.
2. Signs: The macula usually appears normal, but can have mild
pigment mottling. Pt’s may present with congenital nystagmus or
paradoxic pupil constriction.
3. Symptoms: Decrease in visual acuity to 20/200 with significant
photophobia. Pts will have totally absent color vision, with all
colors appearing as shades of grey.
4. Testing: Photopic ERG is significantly decreased while scotopic
ERG will be normal to only mildly abnormal. Fluorescein
angiography is normal (Kanski, 2011).
5. Summary: The pt presented did not have complete color vision
loss, nystagmus, or paradoxic pupil constriction.
v. Retinitis Pigmentosa
1. This pt presented with pigment flecks similar to the bone spicules
found in retinitis pigmentosa and with vessel attenuation.
However, retinitis pigmentosa typically affects peripheral vision
more so than central vision and would not affect color vision.
vi. Chloroquine/Hydroxychloroquine Retinopathy
1. This condition presents with bulls-eye maculopathy similar to that
found in Rod Cone Dystrophies. However, this pt had never taken
any chloroquine or hydroxychloroquine.
vii. Age Related Macular Degeneration
1. This pt presented with macular pigment mottling and scattered
hard drusen characteristic of ARMD, but her visual loss had
started much earlier in life at approximately 20-30 years of age
which is not typical of ARMD. The reduction in visual acuity of
20/400 OD with minimal macular findings and no CNVM is also
uncharacteristic of ARMD.
IV. Diagnosis and Discussion
a. Elaborate on the condition
i. Rod Cone Dystrophies are hereditary conditions with progressive central
vision loss. Prevalence is 1 in 40,000 (Hamel, 2007). There are different
variations including autosomal dominant, autosomal recessive, X-linked
recessive or sporadic forms.
1. Symptoms: Pts will present with normal vision until the second to
fourth decade, and then vision will progressively decrease
bilaterally to a 20/400 level or worse. Vision will be slightly
improved in scotopic environments. Pts may complain of
significant photophobia and difficulty distinguishing between
colors (Gerstenblith, 2012).
2. Signs: Micronystagmus, temporal disc pallor, vessel attenuation,
pigment clumping, or tapetal sheen temporal to the macula may
be observed. Fleck-like pigment clumping may occur in the
peripheral fundus which resembles bone spicules found in
Retinitis Pigmentosa.
a. Pts may show no macular or fundus abnormalities on first
presentation or they may show one of the three main
types of retinal lesions below (Alexander, 2002):
i. The Bulls Eye Lesion: This is the most common type
of lesion in Rod Cone Dystrophies and resembles
the macular appearance found with
Hydroxychloroquine/Chloroquine Retinopathy. A
central dark zone at the fovea with surrounding
RPE atrophy is observed.
ii. Patchy Central RPE Defects: This variant presents
as diffuse pigment mottling in the posterior pole
with pigment clumping.
iii. Localized central RPE and Choriocapillaris Atrophy:
Eventual progression to geographic atrophy is
possible. This type of presentation is associated
with more significantly reduced visual acuity and
early onset.
3. Testing: ERG may show subnormal or non-recordable photopic
responses with reduced flicker fusion frequency though rod
responses are preserved until late in the disease process. EOG is
normal to subnormal. Color vision testing may show severe
deuteron-tritan defects. Fluorescein angiography in the bulls-eye
lesion variant will show a central hypofluorescent area with
surrounding hyperfluorescent window defect (Emiko, 2014).
b. Expound on unique features
i. Rod Cone Dystrophies can be difficult to diagnose due to either minimal
fundus signs or similarities in presentation to the differential diagnoses
discussed above. This pt wasn’t diagnosed until she was 62 years old due
to minimal fundus signs to aid in diagnosis. Mild pigment mottling with
peripheral fleck like pigment clumping and mild temporal optic nerve
pallor were found OU without any bulls-eye maculopathy or significant
foveal atrophy.
V. Treatment and Management
a. Treatment and response to treatment
i. There is no cure for Rod Cone Dystrophies. The best treatments are to
update the pt’s glasses and provide low vision aids when appropriate.
Dark tinted glasses may alleviate photophobia. In one case study, red
tinted glasses were found to not only alleviate symptoms of photophobia,
but to actually improve visual acuity to a certain extent (Young, 1982).
ii. This pt has had several low vision exams in the past. She has received
multiple handheld and stand magnifiers, solar shields in multiple colors,
and a color identifier to aid her in her activities of daily living.
iii. Current research is looking into the possibility of implanting
photoreceptor precursor cells into the retina as a future treatment. The
theory is if these cells are isolated and transplanted at the proper time,
they can mature into healthy photoreceptors. Studies are currently
underway on pts with ARMD as well as Stargardts (Pierce, 2015).
VI. Conclusion
a. There are many hereditary macular or retinal disorders that can present with
similar findings, but through thorough evaluation with additional testing
(including electrodiagnostics, color vision testing, and fluorescein angiography)
the correct diagnosis can be made.
VII. Bibliography
a. Alexander, Larry J. "Hereditary Retinal and Choroidal Dystrophies and
Degenerations." Primary Care of the Posterior Segment. 3nd ed. McGraw-Hill
Companies, 2002. 613-616, 623-625, 629-630. Print.
b. "Clinical Characteristics and Current Therapies for Inherited Retinal
Degenerations." Retinal Disorders: Genetic Approaches to Diagnosis and
Treatment. Ed. Eric A. Pierce, Richard Masland, and Joan Miller. Cold Spring
Harbor Laboratory, 2015. 1-25. Print.
c. Emiko, Inui, Akio Oishi, Maho Oishi, Ken Ogino, Yukiko Makiyama, Norimoto
Gotoh, Masafumi Kurimoto, and Nagahisa Yoshimura. "Tomographic Comparison
of Cone-rod and Rod-cone Retinal Dystrophies." Graefe's Archive for Clinical and
Experimental Ophthalmology 252.7 (2014): 1065-069. Print.
d. Hamel, Christian P. “Cone Rod Dystrophies.” Orphanet Journal of Rare Diseases2
(2007): 7. PMC. Web. 27 Aug. 2015.
e. Holz, F.G., and R.F. Spaide. "Macular Dystrophies." Essentials In Ophthalmology Medical Retina. 1st ed. Springer, 2006. 45-46. Print.
f. Kanski, Jack J., and Brad Bowling. "Hereditary Fundus Dystrophies."Clinical
Ophthalmology a Systematic Approach. 7th ed. Edinburgh: Elsevier/Saunders,
2011. 656-660. Print.
g. "Retina." The Wills Eye Manual: Office and Emergency Room Diagnosis and
Treatment of Eye Disease. Ed. Adam T. Gerstenblith and Michael P. Rabinowitz.
6th ed. Philadelphia: Lippincott Williams & Wilkins, 2012. 345-350. Print
h. Young, RS, RA Krefman, and GA Fishman. "Visual Improvements with Red-tinted
Glasses in a Patient with Cone Dystrophy." Archives of Ophthalmology (1982):
268-71. Pubmed.gov. Web. 26 Aug. 2015.
<http://www.ncbi.nlm.nih.gov/pubmed/6978127>.