Zonular instability common in RP patients with cataracts

This retrospective study found a high prevalence of zonular instability in retinitis pigmentosa patients undergoing cataract surgery. These findings highlight the importance of careful preoperative assessment of lens stability with preparation for adjunctive methods to enhance intraoperative and postoperative lens stabilization.

The authors reviewed the charts of 47 consecutive patients with retinitis pigmentosa who underwent cataract extraction and IOL implantation by a single surgeon. The average patient age was 49 years. Mean follow-up was 23.3 months.

Mean BCVA improved significantly in patients with preoperative vision of 20/200 or better. However, those with preoperative visual acuity of 20/400 or worse generally showed more limited objective improvements, likely because of macular involvement, although most of them reported noticeable subjective improvements.

Nearly 19 percent of eyes were found to have some degree of zonular insufficiency, with 10 percent having phacodonesis discovered during surgery and 5 percent having pseudophacodonesis discovered after surgery. These numbers are much higher than those reported in the literature for routine senile cataract patients.

The authors write that a possible explanation for zonular weakness in retinitis pigmentosa may be from direct damage from toxic substances diffusing anteriorly from a degenerating retina. Photoreceptor degeneration has also been shown to increase expression of pro-inflammatory cytokines and chemokines, leading to a chronic inflammatory state and potentially causing progressive zonular damage. Further histologic investigation into the loss of zonular integrity is needed.