Purpose: To study the incidence and types of cataract in retinitis pigmentosa (RP) and their variations among different forms of RP.
Patients and methods: This analysis was based on data from 473 patients with RP (autosomal dominant, n = 87; autosomal recessive, n = 79; x chromosomal recessive, n = 23; simplex RP, n = 215; Usher's syndrome n = 80; M. Refsum and others, n = 9) that were retrieved from the literature and patient charts in our clinic.
Results: Posterior subcapsular cataract (PSC) developed with the following frequencies for the different genetic types of RP: autosomal dominant, 45.3%; autosomal recessive, 44.0%; x chromosomal recessive, 40.7%; simplex RP, 46.1%; Usher's syndrome, 52.9%. PSC was the only type of lens opacity in patients with Usher's syndrome and autosomal recessive RP.PSC development correlated with early onset of RP symptoms. Nuclear cataracts showed a statistically significant higher frequency in patients with simplex RP (14.8%) than in other genetic types (0-5.9%) (P < 0.01). In addition, nuclear cataracts developed in simplex RP at a significantly later age (69.6 +/- 12.4 years) than PSC (44.4 +/- 12.3 years) (P < 0.001). Patients with cataracts showed significantly worse visual fields than patients with clear lenses (P = 0.00067).
Conclusions: The typical RP cataract (PSC) was found in similar frequencies among all genetic types of RP.PSC was the only type of lens opacity in patients with Usher's syndrome and autosomal recessive RP. Nuclear cataracts developed on average 20 years later than PSC and had their highest incidence in patients with simplex RP. Patients with cataracts showed significantly worse visual field results, indicating a more pronounced retinal pathology.