Efficacy of topical dorzolamide for treatment of cystic macular lesions in a patient with enhanced S-cone syndrome

Abstract

The purpose of this study was to evaluate the efficacy of topical dorzolamide 2% eye drops on macular function and thickness in a case of enhanced S-cone syndrome (ESCS). A 24-year-old Asian man with enhanced S-cone syndrome treated with topical dorzolamide in the left eye participated in the study. Examinations performed before and during treatment were included visual acuity (VA), contrast sensitivity measured with briefly presented grating targets (grating CS) and the Pelli-Robson chart (P-R CS), microperimetry (MP), and spectral-domain optical coherence tomography (SD-OCT). Following 4 months of treatment, the mean thickness of the central 1-mm foveal subfield of the left eye, as measured by SD-OCT, decreased from 551 to 242 μm. Mean MP sensitivity within the central 12 degrees (28 points) increased from 9.4 dB at baseline to 11.2 dB. Although Pelli-Robson contrast sensitivity improved only minimally in the left eye, grating contrast sensitivity improved by more than a factor of two. Mean log MAR VA was 0.22 OD and 1.00 OS (at baseline), which improved to 0.10 OD and 0.66 OS after 4 months of treatment. The results indicate that in our patient with enhanced S-cone syndrome, treatment with topical dorzolamide was effective in improving macular thickness, VA, microperimetry sensitivity, and grating contrast sensitivity. These measures of retinal structure and function are sensitive tools for evaluating the effects of treatment in enhanced S-cone syndrome patients with cystoid macular edema. Further investigation is warranted to assess the relationships among visual performance for daily activities, visual sensitivity, and macular thickness.

Fig. 1

Fundus photographs obtained at the time of presentation of the right eye (A) and left eye (B), demonstrating blotchy pigment clumping along the vascular arcades and the mid-peripheral retina as well as areas of diffuse hypopigmentation for 360 degrees in the mid-peripheral retina in each eye. The left eye (B) showed cystic-appearing lesions within the macula. Autofluorescence (AF) images of the right eye (C) and left eye (D) show a ring of enhanced autofluorescence in the posterior pole in each eye. The image of the left eye (D) shows a faint ring of enhanced autofluorscece within the fovea.

Fig. 2

The full-field ERG for the left eye (pretreatment) shows an essentially non-detectable rod response under dark-adapted conditions (right panel, A) and a mild reduction of cone responses under light-adapted conditions (right panel, B), with atypical cone waveforms (prolonged implicit time) that were consistent with an overabundance of short-wavelength-sensitive cones.

Fig. 3

Spectral-domain OCT scans demonstrate the reduction of the macular cysts and retinal thickness while on treatment with topical dorzolamide 2% in the left (treated) eye (A and B) following two months of treatment. Also, SD-OCT scans showed that retinal thickness in the right (untreated) eye remained essentially constant.

Fig. 4

Microperimetry (MP) testing results from the right eye (A) and left eye (C) at the baseline visit shows isolated patchy areas of subnormal retinal thresholds within the posterior pole. Improvement of microperimetry sensitivity was observed in left eye (D) as well as in the right eye (C) after treatment with topical dorzolamide 2%.