Contact lenses alter accommodative dynamics but enhance stereopsis in myopic anisometropia: A comparative study with ophthalmic lenses

OBJECTIVE: This study compared the binocular and accommodative efficiency of young adults with myopic isometropia versus myopic anisometropia, difference spherical equivalent refraction (SER) ≥ 1.00 diopter (D), when corrected with ophthalmic versus contact lenses. METHODS: Seventy-two participants were categorized into isometropic (n = 36; age 21.92 ± 3.21 years) and anisometropic (n = 36; age 21.44 ± 2.62 years) myopia groups. Binocular and accommodative parameters were clinically evaluated under both ophthalmic and contact lens correction. RESULTS: Ophthalmic lens correction produced no significant differences (p > 0.05) in binocular visual efficiency between the two groups. Conversely, contact lens correction elicited distinct alterations in accommodative and vergence profiles. Myopic anisometropia showed a highly significant increase in accommodative lag when using contact lenses (p < 0.001) and increased negative relative accommodation (p = 0.007) compared to ophthalmic lenses. Furthermore, contact lenses amplified the fusional divergence demand to compensate for esophoria, thereby diminishing the near negative fusional vergence reserve (p = 0.012). Notably, contact lens wear was associated with better stereoacuity compared to ophthalmic lenses, which suggests a potential functional advantage in stereopsis for higher degrees of anisometropia, though this warrants further exploratory validation. CONCLUSION: In conclusion, while contact lenses distinctly alter accommodative and vergence dynamics, they may offer functional advantages in stereopsis for higher degrees of anisometropia. These comparative insights provide valuable clinical guidance for selecting refractive correction modalities to support specific binocular functions and stereoscopic performance.