Preoperative ellipsoid zone width can be used to predict the visual prognosis of cataract surgery in patients with pre-existing retinitis pigmentosa, researchers say. The findings were published in Eye.

To assess the utility of ellipsoid zone width in predicting visual prognosis of cataract surgery, the team conducted a retrospective study of patients with retinitis pigmentosa who underwent uncomplicated cataract surgery between December 2017 and June 2020. They measured preoperative ellipsoid zone width on cross-sectional optical coherence tomography (OCT) images along the horizontal/vertical meridian through the fovea and evaluated pre/postoperative best-corrected visual acuity (BCVA). The primary outcome was postoperative BCVA. 

A total of 38 eyes of 38 patients (mean age, 62.1±11.8 years; 58% women and 42% men) were included in the study. The researchers found that the median logMAR BCVA improved significantly from 0.52 (range, 0.00–3.00) before surgery to 0.07 (range, -0.18–3.00) after surgery (P < .001). The median preoperative ellipsoid zone width was 783 (range, 0–9837) μm for the horizontal meridian, 761 μm (range, 0–10 250) for the vertical meridian, and 769 μm (range, 0–10 043) for the average. 


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The team found that the postoperative BCVA was correlated with the horizontal (r=-0.784, P <.001), vertical (r=-0.777, P <.001), and average ellipsoid zone widths (r=-0.777, P < .001). They also demonstrated the areas under the receiver-operating characteristic curves for the ability of the horizontal, vertical, and average ellipsoid zone widths to discriminate eyes with and without postoperative BCVA ≤ 0.3 were 0.971, 0.960, and 0.963, respectively, with best cut-off values of 513, 608, and 515 μm, respectively.

Limitations of the study included the retrospective design, limited sample size, and manual OCT measurements.

“Preoperative ellipsoid zone width was found to be efficient in discriminating between the eyes with and without a preferable visual prognosis,” according to the researchers. “Restoration of normal vision in terms of visual acuity can be expected in patients with an ellipsoid zone width of approximately 600 μm.” 

The team suggests that future studies with larger sample sizes and automated OCT measurements are needed to verify their results and should include evaluations of other visual functions.

Reference

Sakai D, Takagi S, Hirami Y, Nakamura M, Kurimoto Y. Use of ellipsoid zone width for predicting visual prognosis after cataract surgery in patients with retinitis pigmentosa Eye (Lond). Published online January 1, 2022. doi:10.1038/s41433-021-01878-3