Abstract
Purpose :
While it is well-known that lashes protect the eye from debris, evidence has shown that across mammalian species, there is a standard, optimal ratio1 of eyelash length (mm) to transversal eye width (mm) that minimizes air flow stress, evaporation, and contamination at the ocular surface. We hypothesize that a suboptimal lash ratio might lead to more ocular surface exposure and be relevant to dry eye disease. The purpose of this study was to investigate if there were differences between dry eye (DE) and normal (N) subjects in lash length and lash ratio.
1Amador et.al. J R Soc Interface. 2015 Apr 6;12(105)
Methods :
37 subjects were analyzed in this IRB-approved study: 21 diagnosed with DE (mean age 60 years) and 16 N subjects (mean age 55 years). Informed consent and medical history were obtained from all subjects. DE subjects were required to have ocular discomfort scores greater than 2 (0-4 scale). Subjects underwent slit lamp examinations and lash photography and were assessed for ocular surface staining, tear film breakup time and Schirmer’s test. All subjects completed the OSDI questionnaire. Closed eyes were photographed at 16x magnification at the slit lamp. Images were reduced to gray scale and horizontal image roughness was used after contrast enhancement to define lash parameters. Lash length and lash ratio were calculated.
Results :
As expected, DE subjects had greater fluorescein staining (DE: 9.43±3.08; N: 6.03±2.00) and OSDI scores (DE: 37.95±17.11; N: 2.19±3.13), and lower Schirmer scores (DE: 8.10±5.20; N: 14.53±9.01) (p<0.01 for all outcomes, two-sided Student’s t-test). The mean lash ratio was not different between the two groups [DE: 0.296±0.066; N: 0.310±0.067 (p=0.37)]. However, the lash ratio for subjects under 50 years of age (a subgroup of 6 subjects each) was significantly lower in DE subjects (DE: 0.30±0.03; N: 0.35±0.06, p=0.03). No intergroup differences were found for lash length (p>0.39). Pearson correlations were negative between age and lash ratio (N: r=-0.56, p=0.024; DE: r=-0.27, p=0.24) and age and lash length (N: r=-0.65, p=0.006; DE: r=-0.50, p=0.021). No significant correlations were found between lash parameters and any signs or symptoms.
Conclusions :
Only in younger dry eye subjects was there a significantly lower lash ratio than in younger normal subjects. Lash parameters were also found to decrease with age.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.