Although night-blindness is typically the earliest symptom, little is known about the progression of rod loss in retinitis pigmentosa. Since detectable rod ERGs are unusual in adults with retinitis pigmentosa, despite detectable cone ERGs, it seems likely that the rate of progression is faster for rods than for cones. The ability to assess therapeutic intervention in young patients with measures that show rapid progression should enhance attempts to alter the natural history of this potentially blinding disease. We are presently conducting a prospective natural history study utilizing psychophysical and electrophysiological measures of rod function in a large sample of patients with either retinitis pigmentosa or cone-rod degeneration. The present report contains a preliminary analysis of relative rates of rod and cone ERG loss in these diseases and a summary of yearly changes in parameters of full-field rod ERGs and rod visual fields.

Objective: This study aimed to describe the short-term effects of low-intensity laser treatment in eyes with drusen at risk of having choroidal neovascularization (CNV) develop secondary to age-related macular degeneration. Design: The study design was a multicentered, randomized clinical trial of laser treatment versus observation. Participants: One hundred fifty-six patients without exudative age-related macular degeneration and with more than 10 large (>63 mu m) drusen in each eye were enrolled in the Bilateral Drusen Study. One hundred twenty patients with exudative age-related macular degeneration in 1 eye and more than 10 large drusen in the other eye were enrolled in the Fellow Eye Study, Intervention: The treatment protocol for most (85%) of the eyes consisted of 20 laser burns, 100 mu m in diameter, in a pattern of 3 rows placed between the 12- and 6-o'clock positions beyond the temporal perimeter of the foveal avascular zone. The desired intensity of the burns was a gray-white lesion. Whenever the area of drusen had not been reduced by 50% or more at 6 months, a second treatment was applied nasal to the fovea in a mirror image of the first treatment. During the last 6 months of enrollment, a second laser treatment protocol was adopted that specified 24 laser burns, 100 mu m in diameter, in a circular pattern of 2 rows surrounding the macular drusen. Main Outcome Measures: Change in visual acuity is the primary outcome measure. Incidence of CNV, change in contrast threshold, and change in critical print size are secondary outcome measures. Results: In the Bilateral Drusen Study, CNV developed in 4 of 156 treated eyes and in 2 of 156 observed eyes (P = 0.62); in the Fellow Eye Study, the proportions are 10/59 treated eyes and 2/61 observed eyes (P = 0.02). Changes in visual acuity are similar in treated and observed eyes in the Bilateral Drusen Study through 18 months. However, by 18 months, observed eyes in the Fellow Eye Study have lost more visual acuity than treated eyes (P = 0.02). Changes in contrast threshold are similar in treated and observed eyes in each study, Conclusions: Laser treatment to high-risk fellow eyes may increase the short-term incidence of CNV. Longterm effects in fellow eyes and effects in patients with bilateral drusen require additional observation.

In an effort to minimize surgical and visual morbidity of cryotherapy for retinopathy of prematurity (ROP), 18 eyes of 13 patients with 3 to 7 clock hours of stage 3 ROP with "plus" disease were treated by cryotherapy applications limited to the avascular retina adjacent to the areas of stage 3 disease. In 17 of 18 eyes, this limited use of cryotherapy was sufficient to cause regression of ROP without further treatments. After at least 3 months follow-up, ROP outcome showed a normal macular appearance in 16 eyes; two eyes developed macular dragging; no retinal detachments occurred.

Fifteen eyes believed to be at increased risk for macular hole formation underwent vitrectomy in an attempt to prevent macular hole formation. Full-thickness macular holes have not developed in 10 of 11 eyes with stage 1 macular holes. Four eyes were noted to have small full-thickness foveal defects (stage 2 macular holes) at the time of vitrectomy. Two of the four eyes have not progressed to macular hole formation and have 20/25 visual acuity. All patients have been followed for a minimum of 13 months (median, 18 months). The 12 eyes that have not experienced macular hole formation have had a significant (P less than 0.001) improvement in vision with seven (58%) attaining visual acuity of 20/25 or better. The postoperative foveal electroretinogram (ERG) amplitude was higher than the preoperative amplitude in five of the six eyes tested.

ABSTRACT Episcleral plaque placement requires accurate localization of choroidal melanomas. Available fiberoptic light pipes can be fashioned to become scleral markers and transilluminators. The equipment is available wherever posterior segment surgery is performed. Surgical technique and equipment modifications are described.

Rod ERGs were obtained over a broad range of stimulus intensities from young patients with retinitis pigmentosa and progressive cone-rod degeneration. Intensity-response functions suggest that children with retinitis pigmentosa have reductions in the number of functioning rods and that surviving rods generating the ERG have reduced sensitivity. Children with cone-rod degeneration also have reduced numbers of rods, but the remaining rods have normal sensitivity. These findings suggest that the underlying mechanisms of rod degeneration differ in these two forms of disease and demonstrate that insights into the pathogenesis of hereditary retinal degeneration can be obtained by testing children. The ability to distinguish between retinitis pigmentosa and cone-rod degeneration in children is also important because of differences in the rates of progression between the two classes of progressive retinal degeneration.