Abstract
Purpose: :
Silicone hydrogel (SiH) lenses can cause contact lens induced conjunctival staining (CLICS) in some patients. CLICS may be induced by the higher modulus or unique surface characteristics of SiH lenses, changes in lens parameters during wear, or other factors such as poor lens fit or poor edge design. Three studies evaluated the impact of contact lenses and solutions on conjunctival staining and lens parameters
Methods: :
1) Lissamine green was utilized to systematically identify a lens and solution combination that minimized CLICS in ten patients. Base curve, lens material, or solution was changed to determine the influence of each on CLICS. 2) The base curves of SiH lenses (senofilcon A) were measured following one or two weeks of wear using OPTI-FREE® RepleniSH® or Clear Care®. Recovery of base curves over time and the effect of temperature on the recovery (separate in vitro experiments) were measured. 3) A randomized, investigator-masked, crossover study was conducted (n= 25) wearing SiH lenses (senofilcon A; 8.4 BC) cared for with ReNu MultiPlus®, Complete® EasyRub or Clear Care® for one week each. Lens fit, lens parameters, corneal curvature, and corneal and conjunctival staining were assessed.
Results: :
1) CLICS was observed in all ten patients with their habitual lenses and solutions even though the fit had been considered acceptable. Changing the lens material or base curve, but not the solution, impacted the amount of CLICS. 2) Base curves were steepened to 7.9 to 8.2 after one week of wear independent of solution. Base curves returned to baseline within a few hours of lens removal for both solutions. The base curve changes and recovery are influenced by temperature. 3) Preliminary data indicate that base curve and corneal curvature change following one week of wear. CLICS occurs frequently with the test lenses and may not be influenced by solution.
Conclusions: :
This series of studies indicates that SiH lenses can induce CLICS. This staining may be the result of changes in lens parameters over time as lenses are worn. It is important that practitioners use lissamine green to evaluate CLICS to better assess lens fit to optimize ocular health.
Clinical Trial: :
www.clinicaltrials.gov NCT00799422
Keywords: contact lens • cornea: clinical science • conjunctiva