Comparative study of two silicone hydrogel contact lenses used as bandage contact lenses after photorefractive keratectomy

Silicon hydrogel bandage contact lenses are used to enhance epithelial healing, control surface-generated pain, and prevent epithelial erosions after refractive surgery. Considering the importance of faster reepithelialization in preventing complications of photorefractive keratectomy [PRK] and the fact that the features and specifications of these commercially-available lenses are different and their performance as a postoperative bandage lenses would be different also, the aim of this study was comparison the efficacy of senofilcon A and lotrafilcon A after PRK. In this prospective study, 44 patients with PRK in both eyes randomly received a silicon hydrogel contact lens of senofilcon A in one eye and lotrafilcon A in other eye. Then the epithelial defect size, visual acuity and subjective level of pain and discomfort were measured for both eyes and compared on day 1, 3 and 5 postoperatively. There was no statistical difference in rate of reepithelialization between senofilcon A and lotrafilcon A [P > 0.05]. The mean pain and discomfort index was significantly lower in eyes with senofilcon A [P < 0.05]. The mean subjective visual scores were similar with both bandage contact lenses [BCLs] [P > 0.05]. Silicon hydrogel BCLs are safe and effective for corneal reepithelialization and have great therapeutic outcome on visual outcomes after PRK. But, senofilcon A had better effect on postoperative pain and discomfort which made it superior than lotrafilcon A. However for more conclusive results, it is recommended to study larger sample size with evaluation the possible factors responsible for the obtained findings regarding postoperative pain and discomfort

Stereoacuity following LASIK

To evaluate the effect of laser in situ keratomileusis [LASIK] on stereoacuity [SA]. This prospective study includes 200 patients scheduled for LASIK. SA was evaluated preoperatively and one week, one month and three months postoperatively using the Random Dot test. Patients with preoperative SA worse than 480 sec/arc were excluded from the study. The study included 138 female [69%] and 62 male [31%] subjects. Spherical equivalent was -0.5 to -12.0 D. Mean preoperative SA was 124.80 +/- 124.64 [range 480-15] sec/arc which deteriorated to 138.30 +/- 126.48 sec/arc one week after surgery [P=0.158] but improved to 111.30 +/- 112.15 sec/arc [P=0.002] one month and 103.65 + 112.20 sec/arc [P = 0.001] three months postoperatively. Overall, stereoacuity decreased in 9.5%, increased in 32.5% and remained unchanged in 58% of patients [P = 0.007]. Patients with anisometropia had worse SA; eventually, SA increased in 5 non-amblyopic anisometropic patients. Despite the overall improvement in mean SA after LASIK, a minority of patients experienced decreased SA. Anisometropic patients without amblyopia seem to have a chance for improved SA after LASIK

Effect of captopril on aqueous levels of angiotensin II and its correlation with macular edema in diabetic patients

To determine whether angiotensin II [AT II] levels in aqueous tumor are related to diabetes mellitus and to evaluate the effect of captopril on this level. We also evaluated the correlation between severity of macular edema and captopril use. In a case-control study, aqueous humor samples were obtained at the onset of cataract surgery from 58 eyes of 58 patients, of whom 37 were diabetic. From these latter subjects, 16 had taken captopril [captopril group] for at least six months and 21 had not taken any angiotensin. converting enzyme inhibitor [non-captopril group]. AT II level was assessed by radioimmunoassay. Severity of macular edema was evaluated by clinical examination after surgery. The aqueous level of AT II was significantly higher in diabetic patients [31.0 +/- 7.3 pg/ml] compared to non-diabetics [6.28 +/- 2.8 pg/ml] [Mann Whitney U test, P<0.0001]. In diabetic patients, aqueous concentration of AT II in the captopril group [16.3 +/- 6.5 micro g/ml] was significantly lower than the non-captopril group [75.73 +/- 9.36 micro g/ml] [Mann Whitney U test, P<0.0003]. The severity of macular edema was significantly less in the captopril group compared to the non-captopril group: 68.75% of the captopril group vs 33.3% of the non-captopril group had no macular edema [P<0.005]. These findings suggest that the aqueous level of AT II is higher in diabetic eyes and is correlated with the severity of diabetic macular edema. Considering the possible role of AT II in the pathogenesis of diabetic macular edema, modulation of the ocular renin-angiotensin system may become an important target for its treatment