Retrospective Analysis Comparing the Preoperative and Postoperative "Q" Values for 2 Different Lasers in Refractive Surgery.

PURPOSE: To compare the presurgical and postsurgical corneal asphericity, or "Q value," between VISX Wavefront-guided treatment and Allegretto Wave Wavefront-optimized treatment in photorefractive keratectomy for the correction of myopia. METHODS: This is a retrospective database analysis performed at the Joint Warfighter Refractive Surgery Center, Lackland Air Force Base, TX. All data were accessed through the Institutional Review Board-approved Joint Warfighter Refractive Surgery Center database. Fifty-one patient records (102 eyes) were reviewed to determine the change in the Q value after photorefractive keratectomy for the correction of myopia. RESULTS: The average change in the Q value per diopter of treatment sphere over the entire study population was 0.12 (±0.04) for Allegretto and 0.14 (±0.04) for VISX (P = 0.004). There was no statistical difference among the preoperative and postoperative best-corrected visual acuities (BCVAs), low-contrast BCVA (BCVA 5%), or quality of vision complaints between both platforms. CONCLUSIONS: Low to moderate myopic correction with the Allegretto laser was associated with a smaller change in the Q value per diopter of treatment and therefore more closely maintained the original prolate shape of the cornea when compared with VISX. No difference in the postoperative visual outcome between both groups was detected.

The effect of silicone hydrogel bandage soft contact lens base curvature on comfort and outcomes after photorefractive keratectomy.

OBJECTIVE: To evaluate the relative pain and the relative amount of contact lens loss experienced using two different base curvatures (BCs) of the Acuvue Oasys bandage soft contact lens (BSCL) after photorefractive keratectomy (PRK). METHODS: One hundred forty patients undergoing PRK on either the Allegretto or the VISX laser at the Joint Warfighter Refractive Surgery Center in Lackland AFB, TX, were randomized to one of the two different BCs of the Acuvue Oasys BSCL: 8.4 or 8.8 mm. Patients were evaluated on postoperative days 1 and 4 during which they completed a survey rating absolute pain in each eye on a visual analog pain scale. Lens loss was recorded throughout the study. RESULTS: Patients treated on the Allegretto laser preferred the 8.4-mm BC lens, whereas comfort after treatment on the VISX depended on corneal shape. For VISX, patients with very flat corneas (steep K ≤42 preoperative or ≤38 postoperatively) preferred an 8.8-mm BC lens while patients with very steep corneas (steep K >45 preoperative or >42 postoperative) preferred an 8.4-mm BC lens, though these results were largely not statistically significant. Patients who lost their lenses prematurely tended to be those whose corneal curvature did not match their contact lens BC. CONCLUSIONS: Individuals treated with the Allegretto laser or individuals with more prolate corneas should likely be fit with an 8.4-mm BC Acuvue Oasys BSCL while individuals with more oblate corneas should likely be fit with an 8.8-mm BC lens to minimize postoperative pain and premature BSCL loss.

Novel approach for the treatment of corneal ectasia in a graft.

PURPOSE: The aim of this study was to report the use of novel masking agents during an anterior lamellar keratoplasty performed using a femtosecond laser in a patient with corneal ectasia that was consistent with recurrent keratoconus. METHODS: This is a case report. RESULTS: A 55-year-old man, with a 23-year status after penetrating keratoplasty for keratoconus, presented with a chief complaint of ocular discomfort in the right eye. On slit-lamp examination, the physician estimated 70% to 80% inferior thinning at the graft-host interface with inferior corneal neovascularization. Because of the high risk of developing corneal perforation and the patient's desire to minimize visual recovery time, anterior lamellar keratoplasty was chosen. To minimize the risk of perforation during femtosecond dissection of the anterior lamellar bed, gentian violet and cyanoacrylate glue were used in the area of thinning as masking agents. CONCLUSIONS: This represents the first documented use of gentian violet and cyanoacrylate glue as double masking agents to defocus the femtosecond laser raster pass during keratoplasty.