Peripheral tear mixing under scleral lenses fitted with various clearances

Title Peripheral tear mixing under scleral lenses fitted with various clearances
Author, Co-Author Tiffany Yuen, Bo Tan, Allison Moy, Andrew Graham, Langis Michaud, Meng Lin
Topic
Year
2015
Day
Thursday
Program Number
150062
Room
211-213
Affiliation
University of California - Berkeley School of Optometry
Abstract Purpose: To investigate the influence of scleral lens (SL) fit and design on tear mixing by evaluating post-lens tear exchange at the lens periphery

Methods: Six neophytes were fitted bilaterally with trial SLs of various clearances. Subjects then wore 3 pairs of SLs of different clearances (optimal, shallow, excessive) in randomized order at 3 separate visits at least 1 day apart. Optimal clearance was defined as 200-250 µm, shallow as 100-150 µm, and excessive as 300-400 µm of post-lens tear thickness as measured by OCT. SLs were inserted and settled for 20 min. Tear exchange was measured peripherally using the previously described “out-in method”.1 After placing 5 µL of 2% FITC-Dextran onto the superior bulbar conjunctiva, the post-lens tear film (PoLTF) was monitored through a slit lamp biomicroscope. Out-in time (OIT, sec) was recorded at the first sign of fluorescein in the PoLTF.

Results: The mean OITs were 88±114 sec, 69±98 sec, and 180±134 sec for optimal, shallow, and excessive clearances, respectively. Excluding values affected by peripheral curve compression or impingement, the mean OITs were 17±19 sec, 36±27 sec, and 59±45 sec for optimal, shallow, and excessive clearances, respectively.

Conclusions: Our results suggest that tear exchange is relatively slower when SLs are fitted with excessive clearance. Evaluating peripheral tear exchange could provide valuable information when fitting SLs, especially in determining central clearance.

1. Yuen T, Graham AD, Lee A, Lin MC. Evaluation of two methods for measuring post-lens tear exchange: central and peripheral. 2014. ARVO eAbstract 4667a/A0292a.
Affiliation of Co-Authors Clinical Research Center, School of Optometry, UC Berkeley, Clinical Research Center, School of Optometry, UC Berkeley, Clinical Research Center, School of Optometry, UC Berkeley, École d'optométrie, Universite´ de Montre´al, Vision Science Graduate Group, UC Berkeley
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