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) in patients with and without contact lenses. We also aimed to determine if higher refractive errors made a larger effect on the RNFL and Q value measurements. We examined soft and rigid gas permeable lenses.
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 looking at patients with refractive errors lower than -5 diopters, and above or equal to -5 diopters. For patients with astigmatism, the spherical equivalence was used. Subgroup analysis was done comparing RGP lenses and soft contact lenses.
Results:
see chart
Conclusions:
No statistically significant difference is present in RNFL measurment and OCT quality with or without contact lens wear overall. Subgroup analysis found no statistically significant difference in RNFL. The difference in Q value was not significant in subjects with higher refractive errors. Patients with a lower refractive error had significantly better quality studies without contact lenses. Patients with RGP lenses had better quality studies without contact lenses. Gross examinination of the study images does show more clear images in patients with higher refractive errors when contacts are in. Although not significant, average Q values are higher in patients with contact lenses with refractive errors above -5.00. We conclude that with higher refractive errors, correcting refractive error with contact lenses provides an improved quality which begins to negate the distortion caused by the contact lens itself. 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.
Keywords: contact lens • nerve fiber layer • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)