Comparing the short-term effects of wearing hydrogel and silicone hydrogel soft contact lenses on the bulbar conjunctival microvasculature and tear film.

PURPOSE: To compare the short-term effects of etafilcon A hydrogel and senofilcon A silicone hydrogel soft contact lenses (SCLs) on the ocular surface.

METHODS

This prospective, double-masked, randomised crossover study required 20 participants to wear etafilcon A hydrogel and senofilcon A silicone hydrogel SCLs for seven days each, separated by a two-week washout period. Ocular examinations were conducted at baseline, and on day 1 and day 7 of lens wear. Bulbar conjunctival microvasculature assessment included vessel diameter (D), axial blood flow velocity (Va), cross-sectional blood flow velocity (Vs), blood flow volume (Q), and monofractal dimension (Dbox). Tear film analysis comprised tear meniscus height (TMH), first noninvasive tear break-up time (f-NIBUT), and average noninvasive tear break-up time (av-NIBUT). Participants completed the Ocular Surface Disease Index (OSDI) questionnaire at baseline and day 7 and the Visual Analogue Scale (VAS) on day 1 and day 7.

RESULTS

At baseline, no significant differences were observed between hydrogel and silicone hydrogel SCLs. On day 1 and day 7, both SCLs demonstrated increased Va, Vs, and Q, and reduced TMH, compared with baseline (p < 0.05). Silicone hydrogel SCLs exhibited higher Va, Vs, and Q values on day 1 (p < 0.05), while hydrogel SCLs showed shorter f-NIBUT on day 7 (p < 0.05). Both SCLs displayed increased OSDI and VAS scores over time (p < 0.05), with silicone hydrogel SCLs yielding higher VAS scores than hydrogel SCLs on day 7 (p < 0.05). Univariate analysis suggested that lens wear time (β = 5.1, p = 0.010), lens material (β = 4.2, p = 0.032), Va (β = 4870, p = 0.037) and Vs (β = -6586, p = 0.039) were significantly associated with VAS scores; however, only lens wear time and lens material remained significant in the multivariable model.

CONCLUSIONS

After seven days wear, etafilcon A hydrogel SCLs were associated with greater tear film instability, while senofilcon A silicone hydrogel SCLs resulted in greater conjunctival hyperaemia and more pronounced subjective discomfort.