Optometry case study: Pattern dystrophy

609

by Victor Chong, Optometrist, Specsavers Manukau, New Zealand

History
• A 44 year old male presented c/o blurring at near, eyestrain and a frontal headache for the last year or so. He also mentioned a halo around his central vision in his left eye for the last six months or so.
• GH – good
• POH – none
• FOH – none
• Meds – none

Examination
• Best corrected visual acuity RE 6/6 LE 6/7.5 (no improvement with pinhole).
• IOPs R 16mm Hg, L 18mm Hg at 2pm
• Pupils – PERRLA, no RAPD.
• Butterfly pattern of yellow deposits around both maculae (see retinal photographs)
• peripheral retina normal
• Amsler – the patient reported in the right eye a circular ring of distortion 5 degrees out from centre of fixation (width of about 2-3 squares). The left eye had a similar circular ring 5 degrees out but instead of distortion, the lines in the ring had increased brightness.

Digital retinal photography
RE:

 

 

 

 

LE:

 

 

 

 

Diagnosis
Differential diagnosis:
• Age related macular degeneration
• Epiretinal membrane
• Macular dystrophy

Management
This patient was referred for ophthalmological evaluation where a diagnosis of pattern dystrophy was made. The patient was reassured that the long term prognosis for retaining good central vision in at least one eye was very good and discharged.

Discussion
The term “pattern dystrophy” groups together a series of macular conditions which share the following features:
• autosomal dominant inheritance
• a minimal effect on visual function in the early stages
• a good prognosis for vision

Symptoms:
• Visual acuity tends to remain stable until older age when some reduction may occur

Signs:
• Yellow deposits can be seen as a result of an accumulation of lipofuscin within RPE cells
• typically bilateral and symmetrical
• can mimic ARMD

Management
There is no treatment for pattern dystrophies and patients should be reassured that the condition should not significantly affect their vision, at least until old age. Even then, the degree of vision loss may be quite mild. There is an increased risk of choroidal neovascular membranes forming in these patients so regular Amsler use is recommended.

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