To assess changes in binocular vision measures when switching from spectacles to spherical-equivalent soft contact lenses in patients with low myopic astigmatism.
Approach:
Study Design: An acute, single-visit comparative study involving 36 patients aged 15 to 35 years with low myopic astigmatism.
Participants: Patients with −0.50 to −3.00 diopters of myopia and 0.75 to 2.00 diopters of astigmatism, including habitual and new contact lens users.
Testing Method: Binocular vision testing was conducted with spectacles followed by spherical-equivalent soft contact lenses after a 30-minute stabilization period.
Measurements: Parameters assessed included accommodative amplitude, stereoacuity, horizontal phoria, near point of convergence (NPC), and fusional vergence.
Key Findings:
Contact lenses showed changes in accommodative lag (0.70 to 0.81 diopters), NPC (6.67 to 7.02 cm), and PRA (−2.81 to −3.17 diopters).
Most other measures did not show statistically significant differences between spectacles and contact lenses.
Four patients developed exophoria when switching to contact lenses.
Limitations:
Testing order was not randomized.
Adaptation to contact lenses was limited to a short period.
Study did not include a toric contact lens comparator.
Multiple outcomes evaluated without formal adjustment for comparisons.
Narrative review linked lower vitamin D levels to greater myopia risk and higher omega-3 intake to lower risk, though outdoor exposure may explain the vitamin D association.
