Abstract
Purpose:
Fundus autofluorescence (FAF) imaging is a noninvasive modality that allows evaluating the status of photoreceptor cells and the retinal pigment epithelium. Here we examined wide-field FAF images of patients with cone-dominant hereditary retinal dystrophies and evaluate the clinical utility of the device.
Methods:
We evaluated the right eyes of 37 patients with cone rod dystrophy (CRD), 12 patients with cone dystrophy (CD), and 26 patients with macular dystrophy (MD). MD includes 6 patients with central areolar choroidal dystrophy (CACD) and 15 patients with Stargardt’s disease (STGD). The eyes were divided into three groups based on the area of abnormal FAF. Those patients with abnormal FAF confined to an elliptically shaped central area of 1000 × 700 pixels as measured with ImageJ software® were considered as Type 1, those with abnormal FAF confined to an area of 2000 × 1400 pixels were considered as Type 2, and those with peripheral abnormal FAF were considered as Type 3. The results of visual acuity measurements, kinetic perimetry, and electroretinography (ERG) were compared among the groups.
Results:
There was no significant difference in general patient characteristics among the three groups. The ERG amplitudes recorded under all conditions were smaller among Type 3 patients. The mean amplitude of b-waves measured using dark-adapted 3.0 ERG was 76.4 ± 59.4 µV for Type 3, which is smaller than that measured for type 1 (224.8 ± 90.2, P < 0.001) and type 2 (188.6 ± 72.5, P < 0.001). In addition, type 3 patients showed worse visual acuity (1.04 ± 0.64 logMAR units) than type 1 (0.59 ± 0.55 logMAR units, P = 0.012) and had scotomas of larger area (30.8 ± 18.0 cm2) than type 1 (5.7 ± 5.5 cm2, P < 0.001) and type 2 patients (14.8 ± 11.9 cm2, P = 0.016). The mean amplitude of b-waves measured using dark-adapted 0.01 ERG and scotoma area differed significantly between Type 1 and Type 2.
Conclusions:
The extent of abnormal FAF reflects the functional impairment in patients with cone-dominant retinal dystrophies. FAF measurements are useful for assessing retinal function in these patients.
Keywords: 696 retinal degenerations: hereditary •
550 imaging/image analysis: clinical •
758 visual fields