A double-pass method of evaluating the optical quality of dry eye caused by meibomian gland dysfunction

Abstract

Objective To use double-pass technology to evaluate optical quality by dynamically analyzing the ocular light scatter of dry eye caused by meibomian gland dysfunction (MGD). Methods In a noninterventional, cross-sectional study, results of the following tests were recorded in 56 patients (74 eyes) with dry eye caused by MGD and a control group of 31 participants (53 healthy eyes) : Schirmer Ⅰ test, tear film break-up time (BUT) , meibomian gland grade, modulation transfer function cutoff (MTF cut off) , Strehl ratio (SR) , and objective scatter index (OSI) . The differences between the two groups were compared for the MTF cutoff, SR, the average value of OSI and the corresponding standard deviation (SD-OSI) . The correlations of OSI with MTF cut off and SR were analyzed. Results The result of Schirmer Ⅰ test, BUT, meibomian secretion score, miss rate of meibomian glands, MTF cut off, SR, OSI and SD-OSI in MGD dry eye group were as follows: 4.7±2.8, 4.9±2.1, 3.0±1.2, 3.2±1.3, 24.41±9.12, 0.13±0.06, 2.26±1.08 and 0.61±0.68. The corresponding results for the control group were: 15.7±5.1, 13.2±2.0, 0.5±0.2, 0.6±0.1, 37.24±7.04, 0.23±0.06, 0.71±0.18 and 0.11±0.09. There were statistically significant differences between the two groups (t=-15.815, -22.399, 9.925, 6.965, -8.574, -9.752, 10.341, 5.315, P<0.05) . Both the MTF cut off and SR were negatively correlated with OSI (r=-0.67, -0.60, P<0.05). Conclusion Ocular light scatter in MGD dry eye patients greatly influences retinal images and optical quality. The double-pass technology, which is an objective method for evaluating optical quality, may play an important guidance role in the diagnosis and treatment of dry eye. Key words: Double-pass technology; Light scattering; Meibomian gland dysfunction; Xerophthalmia; Optical quality