Bandage Soft Contact Lenses Role in Pain Control After LASEK: Does Lens Type Make a Difference?

1. Womack Army Medical Center Fort Bragg, North Carolina Bandage Soft Contact Lenses Role in Pain Control After LASEK: Does Lens Type Make a Difference? Darrel K. Carlton, MD Lieutenant Colonel, Medical Corps Warfighter Refractive Eye Surgery Program

2. Nondisclosure Slide • I have no financial relationship or affiliation with any of the products or companies mentioned herein.

3. Background Successful pain control has long been considered the “Holy Grail” of surface ablation. There has been a constant search for this elusive goal. Pain control after surface ablation has been the topic of much research, including this study. Many different medications and treatment modalities have been attempted: Narcotics, steroids (topical and systemic), topical anesthetics, cold balanced saline solution, gabapentin, selective serotonin reuptake inhibitors, nonsteroidal anti-inflammatory agents, the creation of the LASEK procedure itself, and, of course, bandage soft contact lenses have all been tried, with varying success. Whenever one sees so many different ways to address a problem, this suggests that no one treatment is particularly effective.

4. LASEK Background • “Alcohol-assisted flap PRK” was first performed by Azar in 1996. • The term Laser Epithelial Keratomileusis (LASEK) was introduced into the ophthalmic literature by Camellin in 1999. • Purported advantages of LASEK include less pain than PRK, ability to treat thinner corneas than LASIK, no stromal flap complications, and the ability to have larger diameter optical zones than LASIK. • Many minor variations in the LASEK procedure, but all LASEK surgeons use bandage soft contact lenses, both for pain control and to hold the epithelial flap in place.

5. Soft Contact Lens use in Lasek • Conventional hydrogel soft contact lenses have been used primarily, such as the etafilcon A (Acuvue 2, Johnson & Johnson) lenses our facility was using until 2007. • Silicone hydrogel soft contact lenses, with much higher oxygen permeability (Dk) values (and theoretically greater patient comfort), than conventional contact lenses, were introduced in 1998.

6. Study Purpose • The impetus for this study came from hearing anecdotal data from other military refractive surgeons at meetings and from non-peer reviewed literature that the silicone hydrogel soft contact lenses, and the senofilcon (Oasys, Johnson & Johnson) lens in particular, resulted in considerably less pain than conventional soft contact lenses for surface ablation patients. • This study was conducted to see if, in fact, the senofilcon lens resulted in less pain than the etafilcon lens for our LASEK patients. • No direct comparison regarding pain level between conventional soft contact lenses and silicone hydrogel contact lenses was found in review of the literature.

7. Patient Demographics • 99 total patients. • Age range 18-46, mean age 27. • 76 male, 23 female. • 88 myopic patients up to -8.4 diopters (mean -5.3 diopters). • 5 hyperopic patients up to +3.4 diopters (mean +2.2 diopters). • 6 astigmatic patients up to -4.0 cylinder.

8. Surgical Technique • Three surgeons (Barnes-34 patients, Carroll-32 patients, Carlton- 33 patients). • All surgeries performed from March-June 2007. • Both eyes treated consecutively, right eye treated first. • 9.0 mm corneal trephine used to score corneal surface. • 20% alcohol applied to corneal surface within 9.5 mm well for 20-45 seconds. • Superiorly-hinged flap created with a microhoe.

9. Surgical Technique (cont.) • Laser surface ablation was performed using the AMO Star S4 excimer laser. • The epithelial flap was then repositioned and one drop each of moxifloxacin and diclofenac instilled. • The bandage soft contact lens was then placed by surgeon (who was not blinded to which contact lens was applied). • Postoperative medications: fluoromethalone, vigamox, artificial tears, vitamin C, and as needed percocet, valium, phenergan, tetracaine, motrin. • No mitomycin was used.

10. Methods • Double-blinded contralateral study of 99 LASEK patients. • One eye had a senofilcon lens (diameter 14.0, base curve 8.4, Dk 103) placed, while the other eye had an etafilcon lens (diameter 14.0, BC 8.3, Dk 28) placed • Pain level assessed and recorded on postoperative day 1 and postoperative day 5 by refractive surgery technician. • Pain scale 0-10, with 10/10 the maximum. • Chart review by Dr. Carlton.

11. Results • Mean pain level: • Senofilcon day 1: 1.39/10 (95% Conf. Interval 0.95-1.82) • Etafilcon day 1: 2.21/10 (CI 1.70-2.73) • Senofilcon day 5: 0.56/10 (CI 0.28-0.85) • Etafilcon day 5: 1.00/10 (CI 0.59-1.41) • Difference between mean pain levels were found to be statistically significant (P<0.05) for both day 1 and day 5 (the Student’s T-test was used to test for statistical significance).

12. Results • Of the 99 patients: • 60 reported no difference in pain level. • 32 reported more pain with the etafilcon eye. • 7 reported more pain with the senofilcon eye. • No difference in early visual acuity outcomes. • There were no complications.

13. Conclusions • Results suggest that the senofilcon lens results in less overall pain than the etafilcon lens after LASEK, but does not eliminate postoperative pain. • Possible Sources of Error/Study Limitations: • Difference in base curve (senofilcon 8.4 mm vs. etafilcon 8.3 mm), perhaps a tighter fit with etafilcon causing more pain? • Sample size too small? • Chart reviewer bias? • Possible topics for further LASEK research: • Assessment of pain control using different types of silicone hydrogel soft contact lenses, as there are several currently on the market. • Slit-lamp assessments of actual epithelial healing comparing different soft contact lenses.