Aberrations In Dry Eyes And Changes After Instillation Of Artificial Tears

Objective: Xerophthalmia is a frequent disease,whose characteristics is instability of tear film after a blink. At present, because of our insufficient clinical cognition, misdiagnosis and missed diagnosis are common. This study is to investigate the wavefront aberration in dry eyes and normal eyes, to determine the characters of wavefront aberration of dry eyes and the influence of the instillation of artificial tears, to discuss the possibility of applicating WA in the the evaluation of tear film quality,and to find out the the theory for the instillation of artificial tears. Methods: The study comprised 27 eyes of 14 volunteers in whom dry eye had been diagnosed, and 20eyes of 10 normal subjects. Their SIT and BUT results were collected .Ocular aberrations were measured with a WASCA^? aberrometer (Carl Zeiss), which is based on the Hartmann-Shack aberrometer. It analyzed the central 5.0 mm pupil diameter for spherical-like, coma-like, and total higher-order aberrations. The wavefront aberration measurements were done on normal eyes. The same measurements were done on dry eyes before instillation of Hialid^? artificial tears and 10 minutes later. BUT, SIT, the whole high order aberration(HOA), spherical aberration(SA), horizental coma and vertical coma were collected. Then analyzed the results with the software of SPSS 12.0.Results: Classified the eyes by the diagnosis,which was made on the basis of: symptoms of dry eye, Schirmer I test result of <10 mm without anesthesia and TBUT of <5 seconds. There were no significant differences in the mean ages of two groups .The HA,Cx,Cy and SA 10 seconds after a blink increase significantly than 1 second after a blink in dry eyes group (p<0.05) .10 minutes after instillation of artificial tears, the HA,Cx,Cy and SA decrease significantly both 1 second and 10 seconds after a blink. (p<0.05) . Conclusion: Significant increases in aberrations were recorded by a Hartmann-Shack aberrometer soon after a blink in dry-eye patients,while those didn't changes significantly in normal eyes. Measurements of the dynamic changes in the optical aberrations introduced by the anterior tear film surface can give valuable insights into tear film changes.Dynamic wavefront aberrometry could be useful as a noninvasive, objective method for the evaluation of tear film quality. Significant decreases in aberrations were recorded by a Hartmann-Shack aberrometer after artificial tear instillation in dry-eye patients. Instillation of artificial tears can both release the irritations and improve the visual quality.Wavefront aberration measurement may be useful to evaluate the benefits of artificial tear instillation in these patients.