Unique characteristics of two types of retinitis pigmentosa patients with different rod sensitivities.

PURPOSE: To determine the psychophysical differences between two types of retinitis pigmentosa (RP) patients with different rod sensitivities. METHODS: Thirty-five RP patients with a visual acuity of > or =0.7 or better were classified by cone-rod perimetry into type 1, those with undetectable rod sensitivity, and type 2, those with measurable rod sensitivity. Their symptoms, age at onset of symptoms, cone and rod sensitivity, and full-field electroretinograms (ERGs) were compared. RESULTS: The age when the symptoms of night blindness were first noticed was 13.1 +/- 3.3 years (mean +/- SD) for type 1 and 34.5 +/- 14.4 years for type 2 patients (P = 0.0001). One of nine type 1 patients (11%) and 10 of 26 type 2 patients (38%) did not have any symptoms of night blindness. The average rod sensitivity within the central 10 degrees was 43.7 +/- 12.0 dB for type 2 patients with night blindness, and 54.8 +/- 6.4 dB for type 2 patients without night blindness (P = 0.014). One of nine (11%) type 1 patients and 9 of 23 (39%) type 2 patients had recordable ERGs (P = 0.13). CONCLUSIONS: These findings indicate that the two types of RP patients, distinguished by their rod sensitivity, have different psychophysical characteristics of the visual system. The course of the disease process and the long-term prognosis for these two types of patients are different.

Peripheral cone dystrophy: a variant of cone dystrophy with predominant dysfunction in the peripheral cone system.

PURPOSE: To determine the phenotype of 3 patients from 2 pedigrees with an unusual form of cone dystrophy in which the peripheral cone system is more affected than the central cone system, and whose rod system is relatively normal. DESIGN: Three observational case reports with electrophysiologic and psychophysical studies. METHODS: Three patients underwent fundus photography, fluorescein angiography, color vision testing, Goldmann visual field testing, full-field electroretinograms (ERGs), focal macular cone ERGs, and rod-cone perimetry, in addition to routine ophthalmologic examinations. Multifocal ERGs also were recorded from 2 patients. RESULTS: The fundus examination and fluorescein angiogram results essentially were normal except for a mild temporal pallor of the optic disc in 2 patients. The corrected visual acuity ranged from 20/16 to 20/100. Color vision was normal in 1 patient, but was abnormal in 2 patients. A relative paracentral scotoma was detected in 2 patients. Full-field ERG cone responses were reduced significantly, but rod responses were normal in all patients, as in patients with typical cone dystrophy. However, the focal macular cone ERGs were well preserved in all patients. Psychophysical rod-cone perimetry demonstrated that the peripheral cone system was impaired, whereas the rod sensitivity was completely normal. The results of the multifocal ERG in 2 patients supported the findings made by the full-field and focal macular ERGs. CONCLUSIONS: These findings demonstrate that there is a subgroup of patients with cone dystrophy where the peripheral cone system is more affected than the central cone system.

Delayed regeneration of foveal cone photopigments in Vogt-Koyanagi-Harada disease at the convalescent stage.

PURPOSE: To evaluate the physiological characteristics of the macula in patients with Vogt-Koyanagi-Harada disease during the convalescent stage with specific reference to the kinetics of foveal cone photopigment regeneration. METHODS: Six eyes of three patients at the convalescent stage of Vogt-Koyanagi-Harada disease were studied. All the eyes had best corrected visual acuity of 1.0 or better and had had no recurrence of inflammation for at least 12 months after the last episode. Foveal cone densitometry (FCD), focal macular electroretinograms, color vision tests, two-color perimetry, and optical coherence tomography (OCT) were performed. RESULTS: No regeneration of cone photopigments was detected within the 7-minute testing time by FCD in all eyes at the first examination after the last episode. However, the other functional tests were normal, and the OCT-determined macular morphology was also normal. The regeneration kinetics of the foveal cone photopigment improved in three of six eyes at 36, 37, and 19 months after the last episode, whereas the other three remained delayed at 18, 18, and 49 months. CONCLUSIONS: These findings suggest that a disorder of the foveal cone photopigment regeneration, and its recovery, requires a significantly longer time than that of other macular functions in some patients with Vogt-Koyanagi-Harada disease.