EDI OCT evaluation of choroidal thickness in Stargardt disease

Abstract

Purpose: Choroidal thickness (CT) evaluation with EDI-OCT in Stargardt Disease (STGD), considering its possible association with some clinical features of the disease.

Methods: CT was evaluated in 41 STGD patients and in 70 controls. Measurements were performed in the subfoveal position and at 1000 μm nasally and temporally. CT average values in STGD and in the control group were first compared by means of Student's T test. Then, the possible association between CT and some clinical features was evaluated by means of linear regression analysis. Considered clinical parameters were: age, age on onset, duration of the disease, visual acuity, foveal thickness, Fishman clinical phenotype, visual field loss and ERG response.

Results: Average CT was not significantly different between controls and STGD patients. In the STGD group the correlation between CT and age (r = 0.22, p = 0.033) and age of onset (r = 0.05, p = 0.424) was modest, while that of CT with disease duration (r = 0.30, p<0.001) was moderate. CT and foveal thickness were also significantly but modestly correlated (r = 0.15, p = 0.033).

Conclusion: In our series average CT is not significantly changed in STGD in comparison with the controls. Nevertheless a choroidal thinning may be identified in the more advanced stages of the disease.

Fig 1. The pictures compare an EDI-OCT scan where choroidal borders could be reliably identified (A) with another scan with ill-defined choroidal borders (B).

Fig 2. The graphs show the CT values across different subgroups of age (A), disease duration (B), visual acuity (C), as well as with Fishman phenotype (D), visual field severity stage (E) and ERG alteration grade (F).

Fig 3. The pictures outline the variability of choroidal thickness in STGD.

A) In this patient a thin choroid was associated with a Fishman phenotype 2, a relatively early onset (15 years) and a longer duration (11 years) of the disease. Visual acuity was 20/400, visual field loss consisted of paracentral scotomas and ERG photopic response was severely abnormal. B) In this patient a thick choroid was associated with a Fishman phenotype 1, a relatively late onset (25 years) and short duration (5 years) of the disease. Visual acuity was 20/200, visual field loss was limited to a central scotoma while ERG shows abnormal photopic response.