High hyperopia correction with PRK using an aberration-neutral profile and large ablation zone provides good efficacy, safety, predictability and visual outcomes. Relatively low change of corneal spherical aberrations and low increase of hyperopia in the first three postoperative years were observed.
Optical coherence tomography (OCT) is a high-speed and non-contact optical imaging technology widely used for noninvasive cross-sectional imaging of biological objects. Two main OCT technologies have been developed: time domain and Fourier domain technologies. The latter can be further divided into spectral domain OCT, which uses a broadband light source and a spectrometer as a detector, and swept source OCT, which employs a quickly-rotating laser source. Advances in OCT technology have made it one of the most helpful devices in ophthalmic practice. Fourier OCT has revolutionized imaging of the posterior segment of the eye, as well as of anterior structures and has enhanced the ability to diagnose and manage patients. It provides high-resolution information about the tear film, contact lens (CL), a qualitative and quantitative assessment of the anterior eye that is important in contact lens fitting, and allows possible eye surface changes while wearing contact lenses to be monitored. Potential swept source OCT technology applications include industrial processes of lens design and quality control. In this paper, we describe clinical applications and outline a variety of multifunctional uses of OCT in the field of refractive error correction with contact lenses.
Purpose: To evaluate refractive and visual outcomes of single-step transepithelial photorefractive keratectomy (transPRK) in the treatment of mixed astigmatism with the use of an aberration-neutral profile and large ablation zone. Setting: Nicolaus Copernicus University and Oftalmika Eye Hospital, Bydgoszcz, Poland. Design: Retrospective, observational case series. Methods: This study included patients who underwent transPRK to correct mixed astigmatism and completed the 3-year follow-up. Procedures were performed with an Amaris 750S excimer laser using an aberration-neutral profile and optical zone of 7.2 mm or more. Results: A total 48 eyes of 39 patients were included. Preoperatively, mean spherical manifest refraction was +1.37 ± 0.98 diopter (D) (0.25 to 4.00 D), and astigmatism was −4.00 ± 0.76 D (−2.25 to −6.00 D). Three years postsurgery, it was −0.17 ± 0.26 D and −0.41 ± 0.44 D, respectively. Attempted spherical equivalent correction within ±0.50 D was achieved in 45 eyes (94%) and cylindrical correction in 34 (71%). Preoperative corrected distance visual acuity (CDVA) was 20/20 or better in 38 eyes (79%), and postoperative uncorrected was 20/20 or better in 29 eyes (60.0%). No eye had lost 2 or more Snellen lines of CDVA, whereas 3 eyes (6%) gained 2 or more lines. In 4 eyes (8%), haze of low intensity was observed at the periphery, with scores between 0.5 and 1.0, and only 1 eye getting a score of 2 in 0- to 4-degree scale. Conclusions: Mixed astigmatism correction with large-ablation-zone transPRK provided good results for efficacy, safety, predictability, and visual outcomes in a 3-year follow-up.
This study aimed to assess clinical application of the Scheimpflug corneal tomography for objective evaluation of corneal optical density in eyes undergoing Descemet’s stripping endothelial keratoplasty (DSEK). In this prospective study, 39 pseudophakic eyes with bullous keratopathy were enrolled. All eyes underwent primary DSEK. Ophthalmic examination included best corrected visual acuity (BCVA) measurement, biomicroscopy, Scheimpflug tomography, pachymetry, and endothelial cell count. All measurements were taken preoperatively and within a 2-year follow-up period. Gradual BCVA improvement was observed in all patients. After two years, the mean and median BCVA values were 0.18 logMAR. A decrease in central corneal thickness was noted only during the first 3 months postoperatively and was followed by a gradual increase. Corneal densitometry decreased constantly and most significantly in the first 3 months postoperatively. The consecutive decrease in endothelial cell count of the transplanted cornea was most significant during the first 6 months postoperatively. Six months postoperatively, the strongest correlation (Spearman’s r = −0.41) with BCVA was found for densitometry. This tendency was maintained throughout the entire follow-up period. Corneal densitometry is applicable for objective monitoring of early and late outcomes of endothelial keratoplasty, showing a higher correlation with visual acuity than pachymetry and endothelial cell density.
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