The Effects of Disulfiram (Antabuse®) on Visual Acuity in Patients With Retinal Degeneration

Visual acuity testing will be performed by Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity with refractive correction when indicated under photopic and mesopic conditions. The test will be performed by an ophthalmic technician and will be used for research purpose only. The right eye should be tested first. When it becomes evident that no further meaningful readings can be made, the examiner should stop the test. The final visual acuity should be noted. Visual acuity is a range from 20/20 to Light Perception, where 20/20 is considered the normal best visual acuity measurement.

Contrast sensitivity will be measured using Pelli-Robson charts with refractive correction where indicated. When it becomes evident that no further meaningful readings can be made, the examiner should stop the test. The results should be noted. The test will be performed by an ophthalmic technician and will be used for research purpose only. The Pelli-Robson score is a logarithmic measure of the subject's contrast sensitivity range from 0.05 to 2.3, where lower number indicates better sensitivity.

Microperimetry is a technology that allows the study of retinal sensitivity at different foveal and parafoveal areas as well as eye fixation. A microperimeter projects light stimuli of different intensities to the retina to assess the sensitivity of each region and records the patient's responses to these stimuli. It is a technique of functional evaluation, providing a direct correlation between anatomical and functional outcomes. This test will be performed by a trained technician and will be used for research purpose only. The microperimetry sensitivity are given in threshold values in the range -1dB to 36dB, where higher value indicates better sensitivity. The dimensions of the zones of relative sensitivity will be qualitatively assessed where larger zones are better.

SD-OCT is a noninvasive interferometric method that provides high resolution imaging of the retina. Scans will include the macula and optic nerve. This test is part of the standard care for patients with retinal dystrophies and will be taken by a trained technician. The integrity of outer nuclear layer, ellipsoid zone and retinal pigment epithelium will be qualitatively assessed. The width of the outer nuclear layer and ellipsoid zone will be measured (mm) in the vertical and horizontal plane. Shrinking of this zone is indicative of worsened disease.

Fundus autofluorescence measures the intrinsic autofluorescence of lipofuscin and other molecules within the retinal pigment epithelium following excitation. This test is part of the standard care for patients with retinal dystrophies and will be performed by a trained technician. Fundus Autofluorescence will be qualitatively assessed for hypoautofluorescence indicating reduced retinal function and will measure in mm horizontal width of hyperfluorescent ring if present in macula.

This is a non-invasive, non-contact procedure that should take approximately 5 minutes. Photos of the retina, including optic nerve and vessels will be taken by a trained technician. Fundus photographs will be qualitatively assessed for zones of atrophy, amount and distribution of pigment clumps, degree of vessels thinning and optic nerve head pallor. Any change in these areas will be counted as a participant with anatomy changes.

Full field stimulus testing measures the luminescence threshold for the visualization of a stimulus. The subject's pupils are dilated and varying narrow wavelengths of light at varying luminescence are presented to the subject. Full field testing will be completed only in subjects who are able to cooperate with this assessment and will be performed by a trained technician and will be used for research purpose only. Threshold results will be reported in the units of logcd.s.m-2 for brief stimulus, or in the units of logcd.m-2 with longer duration. Threshold results will be reported in the units of logcd.s.m-2 for brief stimulus, or in the units of logcd.m-2 with longer duration.

This is a non-invasive, non-contact procedure that should take approximately 15-30 minutes where the subject responds to different light stimuli. Both eyes will be tested separately and will be performed by an ophthalmic technician. The extent of isopter constriction in degrees will be measured.

This is a non-invasive, non-contact procedure that should take approximately 15-30 minutes where the subject responds to different light stimuli. Both eyes will be tested separately and will be performed by an ophthalmic technician. The location and size of any scotomas will be measure in mm.

The ffERG is a mass electrical response of the retina to photic stimulation. The basic method of recording the electrical response is by stimulating the eye with a various light source, to assess rod and cone function. Results are assessed using a contact lens with an imbedded electrode. The latency in ms will be assessed for 'a' and 'b' wave in both scotopic and photopic conditions. The longer the latency, the worse retinal function.

The ffERG is a mass electrical response of the retina to photic stimulation. The basic method of recording the electrical response is by stimulating the eye with a various light source, to assess rod and cone function. Results are assessed using a contact lens with an imbedded electrode. The amplitude in mV will be assessed for 'a' and 'b' wave in both scotopic and photopic conditions. Lower amplitude indicates worse retinal function.

The mfERG allows assessment of ERG activity in small areas of retinal dysfunction, such as the macular area. A bipolar Burian speculum contact is used. The trace arrays, 3D-response density plot and Ring-average will be assessed. The spatial variations in the responses will be assessed, where delay in latency indicates poorer response.

The mfERG allows assessment of ERG activity in small areas of retinal dysfunction, such as the macular area. A bipolar Burian speculum contact is used. The trace arrays, 3D-response density plot and Ring-average will be assessed. The spatial variations in the responses will be assessed, where reduced amplitude indicates poorer response.

The visual questionnaire will access general health, and vision problems, including photopsias. An adapted version of the Visual Functioning Questionnaire - 25 (VFQ-25). will be used. If the patient is comfortable and able to read it, he/she can answer the questions by his/her own. Electronic version will also be available for patients to use zoom text or contrast adjustment when needed. If the subject can't read the questionnaire, the investigator will assist her/him it will be read to the subject by a clinic staff. The score ranges from 0-100 with higher scores indicating better outcomes.