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>

Tear film function of patients with type 2 diabetes / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the tear film function of patients with type 2 diabetes and to investigate the risk factors of dry eye in these patients.</p><p><b>METHODS</b>Totally 111 patients with type 2 diabetes and 100 age- and sex-matched control subjects were studied. Tear film function was evaluated by dry eye syndrome, tear breaking up time (BUT), corneal fluorescein staining, Schirmer I test (SIt), and tear film lipid layer observation with tear scope. Dye eye score was calculated with the results of these tests.</p><p><b>RESULTS</b>When compared with the controls, patients with type 2 diabetes showed higher dry eye score (diabetics 3.28 +/- 1.56, control 2.31 +/- 1.50, P < 0.01) and faster BUT [diabetics (6.50 +/- 4.84) s, control (12.26 +/- 7.16) s, P < 0.01], but similar SIt [diabetics (10.61 +/- 6.86) s, control (10.92 +/- 7.05) s, P > 0.05]. More diabetic patients were diagnosed as dry eye(diabetics 19.8%, control 8.0%, P < 0.05). According to their retinopathy, the diabetic patients were divided into three groups: without diabetic retinopathy (DR), with background DR, and with proliferative DR. For these three groups, the dry eye scores were 2.95 +/- 1.50, 3.38 +/- 1.48 and 4.11 +/- 1.60, respectively (P < 0.01); the SIt were (10.95 +/- 6.89) mm, (11.71 +/- 7.30) mm and (7.63 +/- 5.20) mm, respectively (P > 0.05); the BUT were (7.53 +/- 5.23) s, (5.88 +/- 4.10) s and (4.47 +/- 4.17) s (P < 0.05). Patients with DR were then devided into two groups: with photocoagulation and without photocoagulation. For these two groups, the dry eye scores were 4.71 +/- 1.14 and 3.26 +/- 1.15, respectively (P < 0.01); the BUT were (2.93 +/- 2.06) s and (6.26 +/- 4.36) s, respectively (P < 0.01); the SIt were (7.21 +/- 6.51) mm and (11.33 +/- 6.73) mm, respectively (P < 0.05); the rates of corneal fluorescein staining were 50.0% and 17.9%, respectively (P < 0.05). Dry eye score had a good correlation with diabetic retinopathy and photocoagulation (P < 0.01), but was poorly correlaed with age, gender, insulin, duration of diabetes mellitus, and metabolic control (P > 0.05).</p><p><b>CONCLUSIONS</b>Patients with type 2 diabetes tend to develop tear film dysfunction. The disorders of tear film quantity and quality seem relevant to the stage of diabetic retinopathy and photocoagulation.</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>