Dynamic assessment of tear-film stability-associated objective vision in mild or moderate dry eyes based on Optical Quality Analysis System parameters

Abstract

Background The progenesis and development of dry eye is closely associated with the stability of tear-film.Dry eyes often show the visual disturbance.Therefore, to evaluate the stability of tear-film based on visual quality and explore the relevant dynamic vision change in dry eyes is of important significance. Objective The aim of this study was to evaluate the dynamic changes of objective scattering index (OSI), modulation transfer function cut off (MTF cut off), objective visual acuity (OVA) with tear-film in the patients with mild or moderate dry eye disease using Optical Quality Analysis System. Methods A clinical diagnosis test was performed.Forty-two eyes of 42 consecutive patients with mild or moderate dry eyes were included in Tianjin Eye Hospital from December 2013 to May 2014 based on 'The Clinical Diagnosis and Treatment Recommendations for Dry Eye from Consensus of Expert Advice in 2013’, and 29 normal eyes of age-and gender-matched 29 healthy volunteers were simultaneously included as the healthy control group.The dynamic retinal images under non-blinking condition during 15 seconds were recorded by OQAS-Ⅱ system, and the OSI, MTF cut off and OVA values at 0, 5, 10 and 15 seconds were obtained, and the differences of OSI, MTF cut off and OVA between 0 second and 15 seconds were calculated (ΔOSI, ΔMTF cut off, ΔOVA) .The dynamic changes of ΔOSI, ΔMTF cut off and ΔOVA with time were evaluated.The sensitivity and specificity of ΔOSI, ΔMTF cut off and ΔOVA for the differential diagnosis of dry eyes were analyzed by receiver operating characteristic curve (ROC curve). Results The OSI values at 5, 10 and 15 seconds in the mild or moderate dry eye group were significantly higher than those at 0 second or those in the healthy control group (all at P<0.05), and the MTF cut off values and OVA values at 5, 10 and 15 seconds in the mild or moderate dry eye group were significantly lower than those at 0 second or those in the healthy control group (all at P<0.05). The ΔOSI, ΔMTF cut off and ΔOVA values were 1.03±1.53, (-8.37±9.64)c/d and -0.30±0.32 in the mild or moderate dry eye group, which were significantly higher than 0.06±0.16, (-0.37±5.27)c/d and -0.03±0.18 in the healthy control group (t=4.10, -5.19, -5.28, all at P<0.05). The area under ROC curve was 0.90, 0.79 and 0.78 in ΔOSI, ΔMTF cut off and ΔOVA, respectively.The sensitivity and specificity of ΔOSI was 78.6% and 93.1% respectively at the diagnostic cut off of 0.3. Conclusions The optical quality parameters related with tear-film stability are gradually reduced with extending of time in mild or moderate dry eyes, but they are stable in healthy eyes.The detecting outcomes by OQAS-Ⅱ system can reflect the dynamic status of tear-film, and this method is of important clinical value for the differential diagnosis and optical quality evaluation in dry eyes. Key words: Dry eye; Tear film; Optical quality; Scattering; Modulation transfer function cut off; Ophthalmic instrument