Comparison of efficacy of two different silicone hydrogel bandage contact lenses after T-PRK.

AIM: To compare the efficacy between two different silicone hydrogel bandage contact lenses after transepithelial photorefractive keratectomy (T-PRK). METHODS: In this randomized controlled trial, a total of 89 patients (178 eyes) who underwent T-PRK at the Qingdao Eye Hospital from October to December 2019 were selected. One random eye wore a Senofilcon A bandage contact lens after surgery, and the other eye a Balafilcon A bandage contact lens. Pain scores, uncorrected visual acuity (UCVA), spherical equivalent (SE), corneal epithelial healing status, epithelial thickness, bandage lenses deposits, lenses movement, and ocular surface conditions were measured and compared. RESULTS: There were no differences between the two groups in UCVA, SE, corneal epithelial healing status, corneal epithelial thickness, tear river heights and tear film rupture time at each follow-up visit. However, postoperative pain scores in the Senofilcon A group were significantly lower than those of the Balafilcon A group (F intergroups=67.833, P<0.001; F time=383.773, P<0.001; F interaction=57.344, P<0.001). The duration of pain in eyes in the Senofilcon A group was shorter than that of the Balafilcon A group (t=-3.326, P=0.001). The surface deposition scores and movement scores of Senofilcon A bandage lenses on the first and fourth days after surgery were lower than those of Balafilcon A bandage lenses (Z=-5.385, -6.782, P<0.001; Z=-8.336, -8.906, P<0.001). CONCLUSION: Both Senofilcon A and Balafilcon A bandage lenses have good efficacy after T-PRK. Senofilcon A lenses are associated with less pain and more comfort compared to Balafilcon A.

[Refractive and biometric changes in adolescent guinea pig eyes in development and recover stages of form-deprivation myopia].

OBJECTIVE: To investigate changes in refraction and vitreous length during form-deprivation and visual re-exposure in guinea pig eyes. METHODS: It was an experimental study. Ninety-six guinea pigs with age of three weeks were randomly divided into form-deprivation and normal control groups (n = 48 in each group). The form-deprivation group was further divided into 4 subgroups (n = 12 in each subgroup) which underwent monocular form-deprivation for 1, 2, 4, and 6 weeks, respectively. At the end of each time point, the form-deprived eyes in all animals were visually re-exposed and followed for 3 (n = 6) and 7 days (n = 6). The control group was also divided into four subgroups (n = 12 in each subgroup) to match the time-points of the form-deprivation group. During form-deprivation and recovery, vitreous length and refraction in each group was measured and compared. RESULTS: There was significant difference in vitreous length (F = 6.108, 28.222, 19.195) and refraction (F = 12.504, 15.003, 6.829) when compared deprived eyes with contralateral eyes 2, 4, or 6 weeks after form-deprivation (P < 0.05). Difference in refraction between deprived eyes and contralateral eyes was -2.36 D, -3.64 D and -3.68 D at 2, 4, 6 week, respectively. Difference in vitreous length was 0.08 mm, 0.19 mm and 0.22 mm. During visual re-exposure, form-deprived eyes changed into hyperopia as compared with contralateral eyes. At day 3 point, there was no significant difference in refraction and vitreous length between form deprived eyes and contralateral eyes in 1 week and 2 weeks groups (F = 0.032, 0.280; P > 0.05). After 7 days recovery, vitreous length and refraction in deprived eyes almost backed to level of contralateral eyes in 1 and 2 weeks groups. At day 3 point, there was significant difference of refraction and vitreous length between form-deprived eyes and contralateral eyes in 4 weeks group and 6 weeks group. After 7 days recovery, there was significant difference in vitreous length for 4 weeks group and there was significant difference in both refraction and vitreous length for 6 weeks group (F = 4.108, 6.317; P < 0.05). CONCLUSION: Form-deprivation causes myopic changes in deprived eyes, during visual re-exposure the refraction recovers and the extent depends on the length of form-deprivation. The recovery rate is faster during the first 3 days and then slower after 3 days. The mechanism of form-deprivation myopia in guinea pig eyes is similar to that of myopia in juvenile human beings.

[Clinical analysis on the effects of laser-assisted subepithelial keratomileusis in treatment of super high myopia].

OBJECTIVE: To assess the clinical efficacy and safety of LASEK in the treatment of super high myopia. METHODS: It was a retrospective case series study. Fifty-six eyes of 33 cases with super high myopia were treated with LASEK. Mean spherical equivalent preoperative was (-11.70 +/- 1.59) D (range from -10.0 D to -15.13 D), mean ablation zone was (5.3 +/- 0.51) mm (range from 4.3 mm to 6.0 mm), mean ablation depth was (146.1 +/- 29.3) microm. The mean time of alcohol used treatment was (29.2 +/- 2.8) seconds. Postoperative follow-up assessments were performed at 1, 3, 6 and 12 months after surgery. Postoperative measurements included slit-lamp microscopy, manifest refraction, un-corrected visual acuity (UCVA), best corrected visual acuity (BCVA), intraocular pressure and haze, etc. The time of follow-up was more than one year. The results were analyzed with ANOVA by SPSS software. RESULTS: Fifty percent of eyes obtained UCVA of > or = 1.0, and 78.6% of eyes obtained UCVA > or = 0.6, at six months after operation. Forty-one percent eyes obtained UCVA of > or = 1.0, and 73.2% eyes obtained UCVA > or = 0.6 at one year postoperatively. The mean UCVA in Snellen chart was 0.85 +/- 0.20, 0.88 +/- 0.28, 0.84 +/- 0.26 and 0.83 +/- 0.28 at 1, 3, 6 and 12 months after operation, respectively. These data were transformed into lgMAR visual acuity and analyzed statistically. There was no significant statistically difference between UCVA at different follow-up periods (F = 0.749, P = 0.518). The postoperative UCVA compared to preoperative BCVA being the same/or improved in 71.4% eyes and decreased in 28.6% eyes at six months after operation; and was 64.3%, and 35.7% at one year after operation, respectively. The effective index was 0.994 and 0.992 at six and twelve months after operation, respectively. The postoperative BCVA compared to preoperative being the same (or improved) and decreased at six and twelve months after operation was 85.3% vs. 14.7%, and 84.8% vs. 15.2%, respectively. The mean BCVA in Snellen chart was 0.90 +/- 0.17, 0.94 +/- 0.24, 0.95 +/- 0.16 and 0.96 +/- 0.16 at 1, 3, 6 and 12 months after operation, respectively. These data were transformed into lgMAR visual acuity and analyzed statistically. There was no significant statistically difference between lgMAR BCVA at difference different follow-up periods (F = 1.567, P = 0.229). The safe index at 6 and 12 months were 1.009 and 1.010. The incidence of refraction regression at 3, 6 and 12 months after operation was 19.6%, 28.6% and 30.3%, respectively. Mean regressive diopter in regressed eyes at 3, 6 and 12 months after operation was (-1.20 +/- 1.08) D, (-1.23 +/- 0.75) D, (-1.49 +/- 1.04) D, respectively. Haze grade 0.5 was 21.4% at 3 months after operation; grade 0.5 and 1 were 8.9% and 5.4% at 6 months after operation, respectively, at 6 months after operation. Haze grade 0.5 was 12.5% at one year after operation. The incidence of high intraocular pressure induced by topical use of corticosteroid eye drop was 8.9%. CONCLUSIONS: LASEK is a safe and effective procedure for correction of super high myopia, though there is still some regression happened after operation and the intraocular pressure should be observed during the follow-up periods.