Abstract
Purpose: :
The efficiency of ATs is demonstrated in a number of ways. Two of the most important are the effect on CS and VA (that is, the VE) and the time it resides on the ocular surface (RT). An ideal AT would minimize initial blur upon instillation while remaining in the eye for an extended time. This study will be the first to concurrently investigate the relationship between RT and the VE in dry eye subjects.
Methods: :
Nine dry eye subjects with mild to moderate dry eye were tested monocularly using the more severe dry eye as the test eye. CS or RT were measured with 25 µl of admixed 0.1% wt/vol FITC-dextran in a solution (non-preserved, buffered saline (control), Optive (Allergan), or Systane (Alcon)) or non-admixed Systane. RT was measured using fluorescent formulations and a scanning fluorometer (Meadows, et. al., 2002). RT is the time, in minutes, for fluorescent levels in the TL to return to baseline based on fluorometry measurements. The VE was determined by measuring CS to a 14 cpd sine wave grating. CS was continually tracked (using a 2 alternative forced choice technique) before and after a drop of AT was instilled in the test eye. Return to baseline sensitivity (RTBS) is the time, in minutes, to reach baseline CS after a drop of AT is applied to the TL. To determine whether FITC-dextran significantly affected the RTBS, both Systane admixed and non-admixed were tested.
Results: :
There was no significant difference in the initial drop in CS between the admixed and non-admixed Systane solutions (t-Test, p > 0.05), thus we compared RTBS and RT results using the admixed solutions. No correlation was found between RTBS and RT for any of the solutions (Pearson correlation, all p-values > 0.05). However, in all solutions, RT was significantly longer than RTBS (t-Test, all p values < 0.05). There was a significant difference in RTBS between saline and Systane (Dunnett’s Simultaneous Test for Pairwise Comparison (DST), p < 0.05), but not Optive (DST, p > 0.05). There was a significant difference in RT between saline and Systane and Optive (DST, all p values < 0.05).
Clinical Trial: :
www.clinicaltrials.gov NCT00553579
Keywords: cornea: tears/tear film/dry eye • contrast sensitivity • cornea: clinical science