Laser-Treated ROP Eyes’ Myopia Severity Risk Rises With Number of Shots

In laser-treated retinopathy of prematurity (ROP) eyes, patients who undergo more laser shots are at increased risk for high myopia, according to an analysis, published in the International Journal of Retina and Vitreous. The investigation also found spherical equivalent (SE) refraction tended toward greater myopia.

The researchers reviewed charts from 17 children (33 eyes) laser-treated for ROP, and 7 patients (14 eyes) used as age-matched controls. Eyes laser-treated for ROP had significantly more negative SE values (P <.001) despite both groups presenting with similar baseline axial length (AL). SE also negatively correlated with the number of laser shots (P <.001).  A linear mixed model was used to assess relationships among SE and 7 factors: age, birth weight, sex, anterior chamber depth (ACD), AL, crystalline lens power (CLP), and corneal refraction (CR).

Resulting data indicated SE was associated with AL, CLP, and CR for children with laser-treated ROP, and that correlations exist between how many laser shots were performed and refractive factors, AL, CLP, and CR. Pearson’s correlation test revealed especially strong significance for CLP (P =.003).

Researchers evaluated structural variation of right vs left case eyes to rule out any unique, individual characteristics. Linear regression analysis and model selection using the Akaike information criterion (AICc) index checked for associations among the difference in SE, or ΔSE, and relationships with the 7 variables, including refractive factors ΔACD, ΔAL, ΔCLP, and ΔCR. Comparable trends were detected among right and left eyes.

“There was also a significant association between the difference in the number of laser shots applied and ΔCLP,” according to researchers. “Taken together, it was suggested that the degree of myopia in laser-treated ROP [eyes] is increased predominantly through increased CLP.”

Laser-treated ROP patients were seen at the outpatient clinic of Tokyo University Hospital from 2004 through 2018. This investigation is limited by potential variability in laser power and duration as performed by 2 physicians, and inclusion of refraction for children of different ages. Because sample size was relatively small, zone and ROP stage subgroup analysis was not possible. Finally, the analysis did not include eyes treated with less tissue-destructive anti-VEGF medications.