Abstract
Purpose :
It is well known that presence of a contact lens (CL) on the ocular surface partitions the tear film (TF), disrupting its integrity. However, there is little evidence regarding the impact of one eye on the other, with respect to TF parameters during CL wear. Hence this study was conducted to evaluate the impact of monocular lens wear on TF stability, volume and lipid layer characteristics.
Methods :
This was a prospective, randomized, 2-day cross-over study on 15 symptomatic (SYM) and 15 asymptomatic (ASYM) soft CL wearers. On Day 1, no CL was worn on either eye (i.e. no CL wear) and on Day 2, a -0.25DS soft CL (comfilcon A) was worn on one eye only (i.e. monocular CL wear). Assessments of non-invasive tear break up time (NIBUT, seconds), lipid layer thickness (LLT, 0-5 grading; 0=absent, 5=colored fringes) and tear meniscus height (TMH, mm) were conducted in the AM (prior to CL insertion for Day 2) and in the PM, after 8 hours.
Results :
The mean age in the SYM and ASYM groups was 31 ± 11.3yrs (12 females and 3 males), and 37 ± 14.7yrs (8 females and 7 males), respectively. In the AM: there was no significant difference in TF parameters between eyes or between study days for either group (all p>0.05).
In the PM, after 8 hours: there was no significant difference in TF parameters between eyes on Day 1 (all p>0.05). Day 2 showed significantly lower NIBUT, LLT and TMH in the CL-wearing eye compared to the fellow non-CL wearing eye in both SYM and ASYM groups (all p<0.05).
In the SYM group, the non-CL wearing eye on Day 2 showed longer NIBUT (mean: 7.8±5.9) and better LLT (mean:3.7±0.2) compared to the same eye on Day 1 (mean NIBUT: 5.0±1.5; mean LLT: 3.3±0.7). The difference, however, did not reach statistical significance (p=0.07 for NIBUT and p=0.16 for LLT). TMH was similar between study days (p=0.98).
In the ASYM group, NIBUT, LLT and TMH were similar for the non-CL wearing eye on Day 2 (mean NIBUT: 10.3±6.9; LLT: 3.3±1.0; TMH: 0.21±0.1) compared to the same eye on Day 1 (mean NIBUT: 10.6±6.6; LLT: 3.5±0.9; TMH: 0.22±0.1); all p>0.05.
Conclusions :
Monocular lens wear resulted in differences between eyes for NIBUT, LLT and TMH, suggesting that these TF parameters are influenced by the interaction of the TF with the CL, but not through an inter-eye interaction. In SYM CL wearers, there was a trend for the non-CL wearing eye to exhibit longer NIBUT and better LLT, potentially to counteract the effects of CL wear in the fellow eye.
This is a 2021 ARVO Annual Meeting abstract.