Analysis of the effectiveness of laser in situ keratomileusis two years after surgery / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the effectiveness of laser in situ keratomileusis (LASIK) for myopia after 2 year follow-up.</p><p><b>METHODS</b>LASIK surgery was performed for 95 eyes (49 cases) with refractive dioptres (from -1.00 to -16.50 D), and then followed up for more than 2 years. The preoperative spherical equivalent was -1.00(-)-16.50 (-6.73 +/- 2.02) D. Patients were divided into two groups including group I with mild to moderate myopia (< or = -6.00 D) and Group II with severe myopia (more than -6.00 D).</p><p><b>RESULTS</b>In group I, uncorrected visual acuity more than and equivalent to 1.0 was in 40 eyes (93.02%), more than and equivalent to 0.8 in 43 eyes (100%). In group II, uncorrected visual acuity larger than and same as 1.0 was in 37 eyes (71.15%), larger than and same as 0.8 in 45 eyes (86.54%), larger than and same as 0.5 in 50 eyes (96.15%), and less than 0.5 in 2 eyes (3.85%). The mean spherical equivalent changed from (-4.14 +/- 0.86) D to (-0.04 +/- 0.14) D in group I and from (-9.00 +/- 1.64) D to (-0.08 +/- 0.20) D in group II. Significant difference was seen in these two groups (P < 0.001). The keratometric powers (K) were reduced from (44.31 +/- 0.78) to (40.11 +/- 1.23) and from (45.46 +/- 1.00) to (38.01 +/- 1.73) respectively, which showed significant difference (P < 0.001).</p><p><b>CONCLUSION</b>The effectiveness of LASIK for mild to moderate myopia or severe myopia is promising and safe.</p>

Static and dynamic contrast sensitivity of myopic eyes before and after laser in situ keratomileusis / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the static and dynamic contrast sensitivity changes in myopic patients before and after laser in situ keratomileusis (LASIK).</p><p><b>METHODS</b>Seventy-three eyes in 37 patients with myopia (with or without astigmatism) who received LASIK were tested for static and dynamic contrast sensitivities using the METRO VISION MON ELEC I system at 0.7, 1.4, 2.7, 5.5, 11, and 22 cpd and cps prior to LASIK, and at one-, three-, and six-month intervals after LASIK.</p><p><b>RESULTS</b>All eyes gained naked visual acuity of more than 0.5 after LASIK. The contrast sensitivity was depressed at all frequencies 1 month after LASIK, as compared to one week prior to LASIK. The depression at 2.7, 5.5, 11 (P < 0.01) and 22 cpd (P < 0.05) was statistically significant for static contrast sensitivity, and also at 5.5 (P < 0.01) and 11 cps (P < 0.05) for dynamic contrast sensitivity. Myopic eyes between 6.25 D and 14.0 D, and astigmatic eyes 2 DC and more, suffered more static and dynamic contrast sensitivity depression than the myopic eyes between 1.25 D and 6.00 D and astigmatic eyes less than 2 DC. Contrast sensitivities were improved and exceeded preoperative levels 3 months after LASIK, and improved even more 6 months after LASIK. All sequences were statistically significant for static contrast sensitivity (P < 0.01), while only 2.7, 5.5, and 11 cps were statistically significant for dynamic contrast sensitivity (P < 0.01). The astigmatic eyes 2 DC and more showed less improvement, even below the preoperative level at 1.4 cps of dynamic contrast sensitivity.</p><p><b>CONCLUSIONS</b>While temporary depression of contrast sensitivity for myopic eyes after LASIK was seen, contrast sensitivity soon returned to exceed preoperative levels at 3 months after LASIK, while improving even more 6 months after LASIK.</p>

Bilateral symmetry of corneal topography / 眼科

Objective To compare the bilateral symmetry characters of corneal topography in patients with different refraction, age and gender.Design Retrospective case series.Participants 1000 eyes of 500 patients who were going to undergo corneal refractive surgery with myopia from 18 to 47 years old.Methods Bilateral corneal topography was obtained using TOMEY Version 3.30.Contact lenses had not been worn for more than a week before the examination,and patients with dry eye or other ocular and systemic diseases were excluded.Main Outcome Measures Symmetry and symmetric rates of corneal topography.Results Bilateral symmetry of loca- tion of the cone apex and refraction:uniform 3.4%;almost symmetry 1.8%;approximately symmetry 79.0%;asymmetry 15.8%.The rates of bilateral symmetry in patients with different refraction:0.05).Conclusions 80% of patients with myopia have bi- lateral symmetric corneal topography patterns.The rates of bilateral symmetry of corneal topography increase with the increase of spher- ical refraction(