The Effect Of Surgically Induced Refractive Anisometropia In Pre-Presbyopic Myopic Patients – A Prospective Cohort Study

To examine the effect of surgically induced refractive anisometropia in pre-presbyopic myopic patients on patient reported outcomes measures (PROMs) and visual function.

Department of Ophthalmology, Rigshospitalet, Copenhagen, Denmark.

Patients underwent delayed sequential bilateral keratorefractive lenticule extraction (KLEx) operation, with the dominant eye operated first and the non-dominant eye nine weeks later. Between surgeries, patients had induced anisometropia > 3 diopters and wore spectacles with optimal correction. Assessments included PROMs (Catquest-7SF, The Quality of Vision, and Binocular Visual Function), uncorrected and corrected visual acuity (VA), aniseikonia, and stereoacuity, all measured preoperatively, between surgeries, and after the second surgery.

79 patients were enrolled. Surgically induced anisometropia was 4.07 ± 0.73 D at one week and 4.10 ± 0.72 D at eight weeks after the first surgery, with corresponding mean aniseikonia of 1.61 ± 1.78 % and 2.04 ± 2.20 %, respectively. Mean binocular uncorrected distance VA was logMAR -0.05 ± 0.14 and -0.10 ± 0.11 between surgeries. PROM scores and stereoacuity worsened significantly after the first surgery. However, these parameters changed between the surgeries, with significantly improvements in PROM scores. During the period of induced anisometropia, PROM scores correlated with lower anisometropia and poorer preoperative stereoacuity.

Surgical induced refractive anisometropia decreased PROM scores and visual function at both one week and 8 weeks after surgery. Over time there was an amelioration of visual function and PROM scoress suggesting that neuroadaptation and blur suppression occur and strengthen over time. Improved PROM scores were associated with lower anisometropia and poorer preoperative stereoacuity.