Short-term visual and ocular responses to a myopia control contact lens: influence of optical zones and hydration techniques

To evaluate the short-term visual performance, subjective acceptance, tear film stability, and ocular physiological response after 1 h of wear of a monthly replacement soft contact lens for myopia control with different central optical zone diameters and hydration modalities.

Thirty myopic young adults (21 ± 1 years) were fitted monocularly with three centre-distance multifocal designs: 3.9 mm optical zone with bulk hydration, 3.9 mm with blister hydration, and 3.6 mm with bulk hydration. A no-contact lens condition served as baseline. High-contrast visual acuity (CDVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions, tear film parameters (tear meniscus heigh, non-invasive tear break-up time), and Likert scales (visual quality, comfort, satisfaction) were assessed using a repeated-measures design.

Photopic CDVA did not differ significantly across conditions (≤ -0.06 logMAR; p = 0.29), while the 3.9 mm design with blister hydration showed a small reduction in mesopic CDVA (0.02 logMAR) compared with the baseline condition (-0.04 logMAR, p = 0.01). CSF was generally worse with contact lens wear compared to baseline, particularly for the 3.6 mm design, which showed lower sensitivity at low and high spatial frequencies, more evident under mesopic conditions (p ≤ 0.01). Subjective visual quality was also lower for this design (4.5/6 vs 5.2/6, p = 0.003), whereas comfort and satisfaction were high and similar across lenses (≥ 5.7/6 and ≥ 4.0/5, respectively; p ≥ 0.10). Non-invasive tear break-up time decreased with lens wear (p ≤ 0.03), with no differences between designs or hydration modalities (≥ 10.68 s). No clinically relevant adverse events were observed.

The evaluated contact lenses showed good short-term performance and tolerance. A smaller central optical zone was associated with modest reductions in contrast sensitivity and perceived visual quality, without clear advantages in other outcomes. Hydration modality did not influence performance.