Frequency of optic disc or parapapillary nerve fiber layer drusen in retinitis pigmentosa.

PURPOSE: To determine the frequency and characteristics of optic disc and parapapillary nerve fiber layer drusen in patients with retinitis pigmentosa and to attempt to document any differences in the frequency within different genetic subtypes of retinitis pigmentosa.
METHODS: This retrospective case series reviewed 117 patients with autosomal-dominant, 84 with autosomal-recessive, and 61 with X-linked recessive forms of retinitis pigmentosa. Color fundus photographs were reviewed independently by three investigators. The presence of optic disc or parapapillary nerve fiber layer drusen was documented only when all three observers concurred as to their presence. The number (isolated or multiple), site (disc, parapapillary, or both), and bilaterality (unilateral or bilateral) were noted in each patient.
RESULTS: Optic disc or parapapillary nerve fiber layer drusen or both were observed in 11 patients (9.4%) with autosomal-dominant, 6 patients (7.1%) with autosomal-recessive, and 7 patients (11.5%) with X-linked recessive types of retinitis pigmentosa. The differences in the observed frequencies were not statistically significant (P = 0.67). Overall, the frequency of optic nerve head or parapapillary drusen or both in 262 patients with retinitis pigmentosa was 9.2%.
CONCLUSION: In a large population of patients with retinitis pigmentosa, our findings suggest that approximately 10% are likely to show optic nerve fiber layer drusen involving the optic disc or parapapillary regions or both. The frequency does not vary significantly between different genetic subtypes.