Mesopic binocular contrast sensitivity under glare conditions after myopic corneal laser refractive surgery

Corneal laser refractive surgery is a common procedure for achieving spectacle independence. Impairment of contrast sensitivity following corneal refractive surgery can have far-reaching consequences, such as restrictions for certain professions or driving bans. The objective of this study was to assess contrast sensitivity following corneal refractive surgery and to identify risk factors contributing to lower contrast sensitivity.

This retrospective study included 174 eyes with a history of corneal laser refractive surgery for myopia correction ≥ 6 months prior who underwent Scheimpflug imaging, a clinical examination, and a test for mesopic binocular contrast sensitivity in glare mode using a Nyctometer. Potential predisposing risk factors were compared between groups with higher and lower binocular contrast sensitivity.

The uncorrected distance visual acuity was ≥ 0.2 logMAR in 98% of eyes, and the postoperative spherical equivalent was between - 1.5 D and + 1.5 D in 99% of eyes. Moreover, 98% of these patients exhibited a good contrast_(Weber) of better than 63%. A statistically significant association was observed between the decentration of the effective optical zone (p = 0.01), postoperative UDVA (p = 0.01), densitometry (p = 0.03) and the maximum myopic meridian (p = 0.04) with lower contrast sensitivity.

The overall refractive and contrast sensitivity outcomes of myopic corneal laser refractive surgery are favourable. In our population, both lower uncorrected distance visual acuity and higher decentration of the effective optical zone are correlated with lower contrast sensitivity.