Fundus Autofluorescence Patterns And Progression Of Macular Atrophy In Stargardt Disease

Abstract

 

Purpose:

 

To evaluate, using fundus autofluorescence (AF) imaging, the (1) occurrence of macular atrophy, (2) rate of atrophy enlargement (RAE) over time and (3) possible variables that may affect RAE in patients with Stargardt disease (STGD).

 

Methods:

 

Demographics, age of onset, duration of disease, visual acuity and findings on AF images and electrophysiology responses were retrospectively evaluated at presentation and follow-up in a group of 12 patients (24 eyes) with STGD. The existence, enlargement and development of areas of atrophy over time were determined by AF imaging and the effect of the above mentioned variables on atrophic events was sought.

 

Results:

 

Eight females and 4 males with a median age of 42 years (range 24-69 years) were followed for a median of 39 months (range 13-59 months). All patients 12/12 (24/24 eyes) had low AF signal compatible with atrophy at presentation and the areas of atrophy all enlarged during follow-up. Patients were categorised into two groups, homogeneous and heterogeneous, based on the pattern of background AF observed. The "homogeneous" pattern was characterised by an evenly distributed AF signal in the background (Figure 1a); the "heterogenous" pattern by widespread small foci of increased and reduced background AF (Figure 1b). In addition 8/8 patients with the heterogenous pattern of AF developed de novo areas of atrophy at follow up whereas all four patients with a homogeneous pattern of AF did not. The mean RAE for all patients was 1.58 mm²/year (n=24 eyes; SD 1.27 mm²/year) and varied between 0.13-5.27 mm²/year. Both electrophysiology group (Lois et al, Arch Ophthalmol 2001; 119:359-69) and pattern of AF seemed to predict RAE; patients with macular and peripheral cone and rod dysfunction (Group 3) or a heterogeneous pattern of AF having the fastest RAE (1.97 mm²/year and 2.01 mm²/year, respectively).

 

Conclusions:

 

Variable RAE were observed in patients with STGD. AF findings and electrophysiology appear to serve as prognostic indicators for the expansion of atrophy over time, supporting the role of these diagnostic modalities in the evaluation of patients with this inherited macular disease.  

 

Keywords: retinal degenerations: hereditary • imaging/image analysis: clinical • ipofuscin