Abstract
Purpose:
To determine whether increasing periocular humidity would 1) increase the thickness of the tear film lipid layer over the front surface of a soft hydrogel contact lens, 2) increase wearing comfort for symptomatic lens wearers.
Methods:
Symptomatic soft contact lens wearing patients were recruited from a single practice in MA. All patients (n = 25; 5 males, 17 females) had worn their lenses for a minimum of 2 hours and a maximum of 5 hours prior to examination. Inclusion criteria: minimum contact lens wear of twice a week for 5 or more hours at a time; minimum symptom score when wearing the lenses = 3 on a scale of 1-5 (1 = asymptomatic, 5 = intolerable discomfort). Exclusion criteria: all toric lenses; all lenses of over 7.75D, age over 50 years, keratoconus. At three time points during the study (immediately prior to wearing goggles, after 20 mins of continuous goggle wear and 15 minutes after the goggles were removed) patients were required to fill out a symptom questionnaire to assess their ocular comfort. The lipid layer thickness (LLT) was observed and semiquanitatively graded (in 30 nm increments) using an interferometer immediately following each symptom assessment.
Results:
The mean age of the patients was 37.9+/-10.4 years. After the goggles had been worn for 20 mins, 88% reported an increase in their lens wearing comfort of at least one grade and 72 % evidenced an increase in LLT of at least 30nm (1 grade). After the goggles had been removed for 15 mins, only 12% maintained a comfort improvement of at least one grade; 8% reported feeling 1 grade worse than baseline, and only 8% maintained the increase in LLT of at least one grade (30nm); 12% evidenced a decrease in LLT of 30nm from baseline.
Conclusions:
Increasing the periocular humidity results in an increase in the LLT of the tear film over the front surface of the contact lens and simultaneously improves lens-wearing comfort. Presumably, the increased LLT is due to decreased evaporation, which results in a thicker overall tear layer, improved protection of the ocular surface, improved hydrodynamic lubrication for the lid wiper and increased contact lens wearing comfort.
Keywords: 486 cornea: tears/tear film/dry eye