Transient Changes in Wide-Field Choroidal Thickness after Photorefractive Keratectomy for Myopia: A Case-Control...

To investigate the longitudinal changes in choroidal thickness following photorefractive keratectomy (PRK) in young adult myopes.

The study population (age: 28 ± 1 years) consisted of 14 myopic subjects who underwent PRK for myopia correction, and a control group of 13 myopic subjects who did not undergo PRK. Measures of choroidal thickness were obtained at baseline in the control group, and before PRK in the treatment group, and then following 1-week, 1-month, 3 and 6 months. Changes in choroidal thickness across different regions were analyzed over time and between groups using linear mixed models.

The mean spherical equivalent refraction was -3.36 ± 0.31 diopter (D) in the treatment and -2.58 ± 0.30 D in the control group (P > 0.05) at baseline. Longitudinal changes in choroidal thickness were significantly different between the two groups (group by time interaction, P < 0.001). The mean wide-field choroidal thickness increased 1-week post-PRK in the treatment group (8 ± 3 μm), with this change in choroidal thickness significantly greater than the change in the control group (-1 ± 3 μm; P = 0.04). However, changes in the mean wide-field choroidal thickness were not significantly different between the two groups in 1-, 3-and 6-month follow-up visits (all P > 0.05). The observed longitudinal changes were not different across the macular and extramacular regions (P > 0.05).

Small magnitude thickening of the choroid was found to occur uniformly across the wide-field region within 1 week following myopic PRK. However, this change in choroidal thickness was transient and no longer observed within 6 months post-PRK.