Subepithelial corneal haze and myopic regression are potential complications following excimer photorefractive keratectomy (PRK). There are many medical and surgical methods of managing this haze. We present a 37-year-old male myope who underwent PRK and subsequently developed central corneal haze late in the postoperative course. The haze was managed initially with topical medications with limited success. Mechanical superficial keratectomy was done to remove the superficial scar tissue but the haze returned necessitating repeat excimer laser PRK, using a transepithelial technique. The haze did not recur. Both mechanical superficial keratectomy and repeat excimer laser ablation may ameliorate haze. Success of these procedures may depend on the morphology of the haze and the patient's individual wound healing response.

Adult↗

PubMedDate not supplied

Multiple regression and vector analyses of laser in situ keratomileusis for myopia and astigmatism.

PURPOSE: To construct a quantitative model relating refractive results to laser settings and other factors. METHODS: A prospective clinical trial was performed, including 14 surgeons and 523 eyes of 278 patients who desired correction of myopia from -1.00 to -16.00 D (mean, -6.20 D) and astigmatism up to 6.00 D (mean, 1.10 D). Myopia and astigmatism were corrected by laser in situ keratomileusis (LASIK) with sequential spherical and cylindrical ablations using a 5.5-mm ablation zone and a transition zone to 7.0 mm. The Nidek EC-5000 excimer laser and the Chiron Automated Corneal Shaper were used. RESULTS: Surgically induced refractive changes 3 months after surgery were measured. Spherical ablation by LASIK produced a 19% greater refractive change than that predicted by the Nidek PRK algorithm. The laser setting needed to achieve each 1.00 D of cylinder correction induced 1.30 D change in spherical equivalent refraction (0.80 D more than expected). Patient age and nonlinear effects had small but statistically significant influences on refractive outcome. Sex, left/right eye, and surgeon were not significant factors. Residual variations in spherical equivalent refraction included a 0.50-D constant plus 9% of the predicted spherical equivlanet change. Residual variations in the parallel and orthogonal components of cylinder correction were, respectively, 28% and 13% of the predicted cylinder change plus a 0.30-D constant component. The standard deviation of axis alignment error for cylinder ablation was 3.7 degrees. CONCLUSIONS: Cylindrical ablation produced a spherical change that was larger than expected. To compensate for this, spherical ablation should be reduced in eyes with astigmatism. Variability in the correction of astigmatism was proportionally larger than that for spherical correction and was primarily due to magnitude rather than axis error.

Adult↗

PubMedDate not supplied

Monocular diplopia related to asymmetric corneal topography after laser in situ keratomileusis.

PURPOSE: To show a specific relationship between monocular diplopia and corneal refractive asymmetry after laser in situ keratomileusis (LASIK). METHODS: One hundred thirty-eight eyes of 98 patients who underwent LASIK for myopia between -2.12 and -17.75 D were examined under room-lighted conditions. We examined 51 eyes at 2 weeks, 46 eyes at 3 months, 32 eyes at 6 months, and 9 eyes at 1 year after LASIK. We attempted to correlate the presence of monocular diplopia with their corneal topographical features. RESULTS: Eight eyes of five patients (five eyes at 2 weeks, three eyes at 3 months after LASIK) produced symptoms of monocular diplopia. These symptomatic patients had a common corneal topographical feature caused by decentralized or inhomogeneous ablation. Every pupillary area in the patients' topographies contained steeper and flatter areas. The range of refractive power variation in these asymmetric areas was at least 1.50 D. The location of the secondary image correlated with the direction of the steeper area in all eight eyes. Pinhole viewing eliminated or reduced the prominence of secondary images in every case. CONCLUSION: Monocular diplopia following LASIK appears to correlate with postoperative corneal refractive power variation inside the pupillary area, caused by decentralized or inhomogeneous ablation.

Adult↗

PubMedDate not supplied

Bicentennial salute.

Explore the source record for details and available documents.

Dental Assistants↗

PubMedDate not supplied

Workers' compensation systems: purpose and mandate.

This historical overview of workers' compensation reveals the legal, sociologic, and economic benefits to both employees and employers.

Canada↗