Faculty Bibliography

In a survey of 546 rhesus monkeys of various ages, 6.1% of the animals showed ophthalmoscopically visible hypopigmented spots in their maculas. There was a statistically significant correlation between the age of the animal and the degree of hypopigmentation. Electroretinographic responses and visually evoked potentials were evaluated in a selected group of monkeys with and without hypopigmented macular spots. No significant change in retinal function as a result of the macular abnormalities could be detected.

A clinical procedure for determining contrast sensitivity was performed on patients with suspected sella area masses. The test consisted of a series of six plates, each containing a bar pattern of fixed sinusoidal spatial frequency in which contrast varies along the length of the bar. Patients with compressive lesions of the chiasm of optic nerve showed loss of contrast sensitivity over the whole range of spatial frequencies. The general loss in contrast was evident even in patients with 20/20 Snellen acuity. After surgery, contrast sensitivity improved, as did other measures of vision, but significant contrast deficits remained. Contrast sensitivity is a sensitive indicator for the diagnosis and evaluation of compressive lesions of the chiasm

Visual evoked potentials (VEPs) were recorded from four patients with surgically verified chiasmal gliomas. Despite good visual acuity, 6/12(20/40) or better in each eye, these patients showed substantially reduced VEP amplitudes to a diffuse flash stimulus and hardly detectable responses to a highly textured checkerboard-pattern stimulus. The dissociation between evoked electrical activity and visual acuity is noteworthy; this differs from previously reported findings in patients with extrinsic compressing lesions of the chiasm or with lesions of demyelinating disease, which usually reduce VEP amplitude and increase conduction time in rough proportion to a loss of visual acuity

Tyrosinase positive albinism may produce a broad range of iris, hair, and skin pigmentation. The accompanying deficits are likewise variable: acuity may range from 20/25 to 20/400, nystagmus may be obvious or subtle, and photophobia may be a chief complaint or may not present at all. Iris transillumination and fundus examination are the two most important diagnostic procedures the ophthalmologist may employ to detect the ty-pos albino and, along with consideration of hair and skin pigmentation, distinguish this form from the more severely affected tyrosinase-negative albino

A gold foil ERG electrode is described. The device is inexpensive and simple to fabricate. Since it is hooked over the lower lid and makes minimal touch contact with the inferior limbal area, it can be used in circumstances which require prolonged testing of retinal function or in eyes with corneal pathology. Because the optics of the eye are not compromised, it is possible, with the use of appropriate stimuli and response-averaging techniques, to record local EFGs from relatively small retinal areas.

A brother and sister born of a consanguinous marriage had bilateral foveal retinoschisis and a generalized rod-cone dysfunction. This was associated with nyctalopia, hyperopia, minimal vitreous opacities in the sister, a paramacular tapetal sheen reflex, normal retinal vessels, an abnormal electroretinogram, and a normal electro-oculogram in the less affected brother. Foveal retinoschisis is not pathognomonic for x-chromosome-linked juvenile retinoschisis. It may be seen as a manifestation of a macular dystrophy or associated with a generalized tapetoretinal dystrophy