Purchase this article with an account.
Johan Hedström, Baskar Theagarayan; Effect of dynamic changes in the tear film on the optical quality in normal and dry eyes. Invest. Ophthalmol. Vis. Sci. 2013;54(15):6038.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study was to investigate the influence of changes in the tear film quality (post-blink) on the optical quality of the eye in both normal and dry eye subjects.
The sample size consisted of 30 subjects with an average age of 26 ± 9.5 yrs. All the subjects had a best corrected visual acuity of 20/20 or better. Thirteen subjects were diagnosed with dry eye and the rest were normal, following tests involving Tear Break-up Time, Tear Thinning Time, Schirmer 1 test, and a questionnaire, (Texas Eye Research and Technology Center Dry Eye Questionnaire). Ocular wavefront aberrations were measured using a Complete Ophthalmic Analysis System (COAS-HD/VR), an aberrometer with an open field of view. All the measurements were performed on the right eye for a 5 mm pupil diameter while the subjects were fixating on a non-accommodative target at a 3 m distance. Subjects were asked to blink once and to keep their eyes open without blinking for a period of 10 seconds. Subjects’ blink was monitored using the iris camera in the aberrometer. During this 10-second period ocular aberrations were measured continuously with a rate of 2 reading per second.
The mean higher-order root mean square aberrations (HORMS) in the normal group was 0.18 ± 0.06 μm and in the dry eye group was 0.16 ± 0.05 μm. There was no significant difference in the mean values between the two groups (p = 0.2). Regression analysis showed a significant increase in the HORMS with time in the dry eye group post-blink (r = 0.6, p < 0.05) whereas in the normal group there was no significant correlation between HORMS and time (r = 0.1, p > 0.05). The mean values of the Tear Break-up time, Tear thinning time, Schirmer 1 test, and the questionnaire were significantly different compared to the normal group (p < 0.05).
The stability and the quality of the tear film in the dry eye subjects were reduced with time resulting in an increase in the Ocular aberrations and hence could affect the image quality of the eye.
This PDF is available to Subscribers Only