Figure 1.
Neuroophthalmology and Ocular Anatomy of the Blind Female Subject and a Normal Control
The left panel shows fundoscopy findings of the 87-year-old blind female subject (A) and a representative ocular-coherence tomogram for the peripheral retina (C) and central macula region (D) of the left eye, compared with a normal age-matched sighted control (B, E, and F). Her retina is abnormally thin (less than 160 microns) and there is no identifiable outer nuclear layer or photoreceptor layer, suggesting that photoreceptors are absent, and the choroid has abnormally high reflectivity (Ch) in contrast to the normal age-matched subject (E and F), where stratification within the neurosensory retina, particularly the outer nuclear layer (ONL), can be seen. By contrast, the ganglion cell and nerve fiber layers of the inner retina of the blind woman are of normal thickness, and there is no cellular disruption, allowing clear recognition and delineation of normal histo-architecture in both retinal periphery and macula. In (G), comparison of the normal macula profile in an age-matched individual (within green limits, as shown in OCT image in [F]) illustrates loss of normal macular contour in the blind subject (black line, as derived from [D]). The normal distribution percentile correlates the color-coded areas of the figure to percentages of age-matched people who might possess retinae within that region. V = vitreous, NR = neurosensory retina.
The right panel shows electroretinographic responses from the female subject (A, C, and E) and an age-matched, normal eye (B, D, and F) for dark-adapted (rod-photoreceptor predominant) responses (A and B); dark-adapted, light-adapted (mixed photoreceptor) responses (C and D); and light-adapted (cone predominant) responses (E and F) to 30 Hz flicker stimuli. White-light stimuli at 3.0 cd s/m2 intensity were used for all tests and began at the start of recordings in all cases. The traces for the blind subject show no detectable electroretinographic responses (Note: [C]shows a drifting baseline.).