Corneal Staining and Physiological Compromise After Eight Hours of Soft Contact Lens Wear

Not Applicable

Completed

Interventions: Device: ReNu Multiplus multipurpose disinfecting solution
Device: Control

Lead Sponsor: Southern California College of Optometry at Marshall B. Ketchum University

Brief Summary: The purpose of this study is to assess corneal staining and to measure the relative corneal epithelial "barrier" function (the degree to which the cornea can prevent penetration of colored sodium fluorescein dye into the eye) after 8 hours of wear with a known soft contact lens and multipurpose lens care solution combination.

Detailed Description: This investigation will evaluate corneal staining and epithelial barrier function after eight hours of contact lens wear, which is past the peak staining time and more typical of daily lens wear time. A silicone hydrogel lens and multipurpose solution combination shown to induce significant corneal staining ( e.g. equivalent Grade 3 out of Grade 4 scale) will be used to evaluate potential corneal compromise. The study will be a prospective, single-center, double-masked, contralateral, daily wear investigation in adapted soft contact lens wearers. After a three day washout period (without lens wear, lenses will then be worn on one day for eight hours. Corneal staining and barrier function will be determined for a regimen and a saline control situation for each subject. Staining will be graded using the Efron Grading Scale, and permeability data will be estimated as the fluorescein penetration rate, Pdc in nm/sec for the test and control condition.

Recruitment & Eligibility

Inclusion Criteria

At least 18 years of age.
Understand your rights as a research subject and give written informed consent by signing the Informed Consent Form, Subject Bill of Rights, and Patient Authorization for Use and Release of Health and Research Study Information (HIPAA form).
Be likely to finish the entire study, understand the study instructions, and be willing to follow the instructions.
Contact lens prescription between +4.00 D to -9.00 D (spherical equivalent).
Best correctable visual acuity of at least 20/40 in each eye.
Willing to de-adapt (do not wear) from habitual contact lenses for a period of at least two days prior to eligibility visit and at least two days prior to the testing day.
Possess a functional spectacle (eyeglass) prescription to allow adequate vision during the de-adaptation and barrier function determination periods.
No known allergies, which may interfere with contact lens wear.
No known systemic (pertaining to general health) disease, or need for medication that may interfere with contact lens wear (i.e. antihistamines, beta-blockers, steroids).

Exclusion Criteria

Less than one month successful, full time (defined as at least 8 hours per day, and more than 5 days per week) soft lens wear.
Clinically significant corneal swelling (greater than grade 3 or 4 on a 0-4 scale), corneal blood vessel growth (vascularization), corneal staining, bulbar redness, tarsal redness, or any other abnormality of the cornea that may cause unsafe contact lens wear.
Any active ocular infection.
Prior corneal refractive surgery (i.e., LASIK, PRK, etc).
Have used medications within 24 hours of study entry or have an ongoing need to use ocular medication.
Are taking part in any other study or have taken part in a study within the last 14 days
Have a medical condition that your study eye doctor thinks may make it not appropriate for you to participate in this study.
Are pregnant, or anticipate becoming pregnant during the course of this study.

Arm && Interventions

Group	Intervention	Description
Test eye	ReNu Multiplus multipurpose disinfecting solution	Uses ReNu Multiplus as multipurpose soaking solution
Control	Control	A new lens (PureVision) is soaked for 2 hours in non-preserved saline

Primary Outcome Measures

Name	Time	Method
The Primary Outcome Measure Will be Corneal Epithelial Dye Diffusion Rate in Nanometers Per Second, for the Test and Control Eyes.	After eight hours of wear	The fluorescein dye diffusion rate in nanometers per second, is a diffusion rate into the corneal tissue. The fluorescein dye diffuses from the tears, where it is in high concentration, into the cornea, where it is in low concentration. It's diffusion is limited (or not) by the barrier properties and health of the epithelium.
Permeability Rate, nm/Sec	After eight hours of wear	A penetration rate, in nm/sec

Secondary Outcome Measures

Name	Time	Method
The Secondary Outcome Measure Will be the Corneal Staining Grade, Compared Between the Test and Control Eye, as Well as Between the Baseline and Final Staining for Each Eye.	After eight hours of wear	Corneal staining represents corneal abrasion or damage. It is graded by us on a 0 - 4 scale (4 being worst) in five corneal sectors. The total score per cornea or eye is thus graded on a 0 - 20 total scale.