To determine the effect of axis orientation on visual performance in astigmatic eyes. Department of Ophthalmology, Kitasato University, Kanagawa, Japan. Investigational simulation. Healthy volunteers with no ophthalmic disease other than refractive errors were enrolled. After cycloplegic refraction was fully corrected with a 3.0 mm artificial pupil, with-the-rule (WTR), against-the-rule (ATR), and oblique (OBL) astigmatism of 1.0 diopter (D), 2.0 D, and 3.0 D were produced using trial lenses in each subject. Distance visual acuity and reading performance with uncorrected astigmatism imposed by the trial lenses under cycloplegia were assessed. Reading performance was determined from reading acuity and maximum reading speed using the Japanese version of the Minnesota Low Vision Reading Test acuity charts. Distance visual acuity and reading performance in the 38 volunteers decreased significantly with increasing astigmatism (P<.001, analysis of variance). Distance visual acuity, reading acuity, and maximum reading speed with uncorrected astigmatism were significantly affected by axis orientation at each diopter of astigmatism (P<.05, 1.0 D and 2.0 D; P<.001, 3.0 D). All parameters showed significantly better values in eyes with WTR or ATR astigmatism than in eyes with OBL astigmatism at each diopter (P<.05); there were no significant differences between eyes with WTR astigmatism and eyes with ATR astigmatism. Eyes with OBL astigmatism had significantly lower visual performance than eyes with WTR or ATR astigmatism. Correcting the preexisting astigmatism to acquire excellent visual outcomes may be necessary, especially in eyes with OBL astigmatism. No author has a financial or proprietary interest in any material or method mentioned.

Purpose. To evaluate the efficacy of collagen cross-linking (CXL) one year after treatment for keratoconus compared to no treatment by summarizing randomized controlled trials (RCTs) using a systematic review. Methods. Trials meeting the selection criteria were quality appraised, and the data were extracted by two independent authors. The outcome parameters included maximum keratometry (Kmax), corneal thickness at the thinnest point, best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), spherical equivalent (SE) refraction, and cylindrical refraction one year after CXL. We compared the changes in the above parameters with the control group. Results. We identified five RCTs involving 289 eyes that met the eligibility criteria for this systematic review. The changes in BSCVA from baseline to one year exhibited a significant difference between the two groups. There was no statistically significant difference between the two groups for changes in corneal thickness and cylindrical refraction. We did not conduct a meta-analysis in Kmax, UCVA, and SE refraction because their I2 values were greater than 50%. Conclusions. According to the systematic review, CXL may be effective in halting the progression of keratoconus for one year under certain conditions, although evidence is limited due to the significant heterogeneity and paucity of RCTs.

This review compared the clinical results of transepithelial corneal crosslinking (CXL) to epithelium-off (epi-off) CXL in progressive corneal ectasia using a metaanalysis. The Cochrane databases and Medline were searched for randomized controlled trials (RCTs). Seven RCTs involving 505 eyes that met the eligibility criteria were identified. The epi-off CXL group showed significantly better outcomes in postoperative changes in maximum keratometry (K) during 1-year observation periods. Transepithelial CXL resulted in significantly greater post-treatment central corneal thickness and best spectacle-corrected visual acuity (BSCVA). The presence of a postoperative demarcation line was significantly more frequent after epi-off CXL than that after transepithelial CXL. No statistically significant difference was found between other parameters. Although patients in the transepithelial CXL group demonstrated a greater improvement in BSCVA compared with patients in the epi-off CXL group at the 1 year follow-up, transepithelial CXL had less impact on halting progressive corneal ectasia in terms of maximum K than epi-off CXL.

To compare the vision-related quality of life 5 years after Implantable Collamer Lens phakic intraocular lens (pIOL) implantation and after wavefront-guided laser in situ keratomileusis (LASIK) for myopia. Department of Ophthalmology, Kitasato University, Kanagawa, Japan. Retrospective case series. Quality of life was measured with the National Eye Institute Refractive Error Quality of Life instrument in consecutive patients 5 years after pIOL implantation or wavefront-guided LASIK to correct myopia. Phakic IOL implantation was performed in 48 patients and LASIK in 55 patients. The scores for activity limitations, symptoms, appearance, and satisfaction with correction were significantly higher in the pIOL group than in the LASIK group (P<.05, Mann-Whitney U test). No significant differences in other scores were observed between the 2 groups (P ≥.05). The scores for near vision and dependence on correction were significantly higher in the younger subgroup than in the older subgroup with both techniques. Phakic IOL implantation may offer significant vision-related quality-of-life advantages (eg, fewer activity limitations and symptoms and better appearance and satisfaction with correction) over wavefront-guided LASIK for myopia in the long term. Moreover, refractive surgery may provide a better quality of life in younger patients.

To assess the repeatability and agreement of corneal power, corneal astigmatism, axis location, and astigmatic vector component measurements using an autokeratometer and a corneal topographer in healthy subjects. Department of Ophthalmology, Kitasato University, Kanagawa, Japan. Evaluation of diagnostic test or technology. Keratometric readings were obtained with an ARK-700A autokeratometer and an Atlas corneal topographer. Measurement repeatability and agreement in corneal power (flattest and steepest meridians), mean corneal power, corneal astigmatism, axis location, and astigmatic vector components (Jackson cross-cylinders J0, J45) between the devices were evaluated. The repeatability of both devices in the flattest and steepest meridians, mean corneal power, corneal astigmatism, axis location, J0, and J45 was high. The 95% limits of agreement between the 2 devices were from -0.51 to 0.48 diopters (D) for the flattest meridian, from -0.74 to 0.71 D for the steepest meridian, from -0.56 to 0.53 D for the mean corneal power, from -0.58 to 0.58 D for corneal astigmatism, from -15.3 to 17.5 degrees for axis location, from -0.32 to 0.30 D for J0, and from -0.22 to 0.20 D for J45. In eyes with a small amount of astigmatism, there was wider disagreement in axis location between the 2 devices. Both devices provided excellent repeatability and comparability of corneal powers and corneal astigmatism, suggesting they can be used interchangeably for measurement of these corneal variables in healthy eyes. However, disagreement in axis location between the 2 devices was not negligible in some eyes, especially in those with low astigmatism.