Pooja B. Jamnadas MD, Marie Brenner, MS4, Peter Russo, OD, Shuchi Patel MD

1. CORRELATION OF RETINAL NERVE FIBER LAYER MEASUREMENTS WITH AND WITHOUT CONTACT LENSES MEASURED IN PATIENTS WITH ASTIGMATISM Pooja B. Jamnadas MD, Marie Brenner, MS4, Peter Russo, OD, Shuchi Patel MD Loyola University Medical Center, Department of Ophthalmology, Maywood IL INTRODUCTION RESULTS ABSTRACT Contact Lenses Retinal nerve fiber layer (RNFL) measurements are often used to aid ophthalmologists in the diagnosis and management of glaucoma. One of the challenges in measuring RNFL is obtaining good quality scans with accurate measurements. Our study serves to report the effects of contact lenses wear on RNFL measurements. Furthermore we sought to determine if the degree of refractive error impacts RNFL measurements or Q values and if the measurements in the axis of astigmatism and 90 degrees from the axis of astigmatism differ. Purpose: The purpose is to determine if statistically significant differences exist between retinal nerve fiber layer(RNFL) measurements and quality (measured in Q value) of optical coherence tomography(OCT) studies in patients with and without contact lenses. We compared patients with increasing amounts of refractive error and patients with astigmatism. Methods: After obtaining IRB approval and consent, patients in the Loyola eye clinic had their RNFL measured with and without contact lenses using the Heidelberg Retina Tomograph. The patient's refractive error, RNFL, and Q value were recorded. A paired t test was used comparing the average RNFL and Q value with and without contact lenses. A subgroup analysis was done examining the effect of increasing refractive error on the RNFL and Q value measurements. For patients with astigmatism, an unpaired t-test was used to compare the change in RNFL with and without contacts, both in the axis of their astigmatism and 90 degrees away from their axis of astigmatism. Results: No statistically significant difference is present in RNFL measurements and OCT quality with or without contact lens wear overall. Subgroup analysis only found a statistically significant difference in Q value measurements in patients between -2.50 and -5.00 of myopia. Subgroup analysis for increasing refractive error showed no statistically significant difference in RNFL measurements. The difference in RNFL measurements with and without contact lenses in the axis of astigmatism compared with measurements 90 degrees from the axis of astigmatism was also not statistically significant. Conclusions: We conclude that according to our study there is no statistically significant difference in OCT RNFL measurements and quality of measurements with and without contact lenses. The only subgroup that does show a statistically significant difference are patients with -2.50 to -5.00 diopters of myopia when measuring Q value. This subgroup also had the largest number of patients. Therefore we need to extend our study to include more patients with higher refractive errors to see if a larger n will allow for results to reach statistical significance. Financial Disclosures: None Acknowledgements: The Richard A. Perritt Charitable Foundation Comparison of RNFL with and without contact lenses METHODS • IRB approved, prospective case control study • 27 patients that presented to the Loyola eye clinic were recruited for the study • Patients were provided appropriate informed consent and made aware of the risks and benefits of participation • Patient’s RNFL was measured with and without their daily contact lenses in place • We studied refractive error, RNFL, Q value with and without contact lenses in place • Subgroup analysis was conducted with chi square analysis analyzing whether a refractive error ≤ -2.0, between -2.5-5.0, and >-5.0 diopters impacted pertinent variables • 15 eyes had astigmatism • For patients with astigmatism, measurements were recorded in the axis of astigmatism and 90 degrees away Comparison of difference in RNFL measurements with and without contact lenses in axis of astigmatism compared to 90 degrees from axis of astigmatism No Contact Lenses At our institution CONCLUSIONS • Overall, there was no statistically significant difference in RNFL or Q value with and without contact lens wear • In subgroup analysis with regards to refractive error, the difference in Q value was only statistically significant in patients with a refractive error between -2.50 and -5.00 diopters of myopia • In subgroup analysis with regards to refractive error, there was no statistically significant difference in RNFL measurements with and without contact lenses • When examining the difference in RNFL measurements with and without contact lenses in the axis of astigmatism compared to measurements 90 degrees from the axis of astigmatism, there was no statistically significant difference in measurements RESULTS Comparison of Q value with and without contact lenses