Myopic regression after photorefractive keratectomy: a retrospective cohort study

Background: Myopic regression is a major complication of photorefractive keratectomy (PRK). The rates and causes vary considerably among different studies. This study aimed to investigate myopic regression at six months after myopic PRK. Methods: In this retrospective cohort study, we included all eligible patients with myopia ranging from - 0.75 to - 9 D, aged 18 to 50 years, who underwent PRK by a single surgeon with the availability of preoperative and postoperative data at six months after the initial procedure. All participants underwent comprehensive ophthalmic examinations preoperatively and at six months post-PRK. Overcorrection was planned based on the participant’s age range to achieve the desired refractive result after PRK. All patients received the same postoperative antibiotic and steroid eye drops in a similar dosage regimen, and the contact lenses were removed after complete corneal epithelial healing. Based on the spherical equivalent of refraction six months after PRK, eyes without and with myopic regression were allocated into groups 1 and 2, respectively. Results: We included 254 eyes of 132 patients who underwent myopic PRK with a mean (standard deviation) age of 30.12 (7.48) years; 82 (62.12%) were women and 50 (37.88%) were men. The frequency of myopic regression was significantly lower in patients with younger age, lower preoperative cylindrical refraction, and lower ablation depth (all P < 0.05). Overcorrection was more successful in eyes with low myopia than in eyes with high myopia (P < 0.05). The highest frequency of myopic regression occurred in eyes with moderate myopia (25.68%), followed by eyes with high myopia (20.0%) and low myopia (6.54%). Among different age groups, patients aged less than or equal to 30 years had a lower frequency of myopic regression. The frequency of myopic regression in the different age groups was 5.0% at 18-20 years, 7.46% at 26-30 years, 12.28% at 21-25 years, 21.31% at 31-35 years, and 26.53% at 36-50 years. Conclusions: Overcorrection was more successful in eyes with low myopia than in eyes with high myopia. The success rate was higher in younger patients with lower astigmatism and ablation depths. Myopic regression was most frequent in eyes with moderate myopia, followed by those with high and low myopia. Further studies should replicate our findings over a longer follow-up period with a larger sample size before generalization is warranted

The Effect of Resistance Training on Plasma Hydrogen Peroxide (H2O2) Level in Older Women

Introduction: The prevalence of chronic diseases increases with age. Increased production of Reactive Oxygen Species (ROS) involves in the pathogenesis of cardiovascular diseases such as coronary atherosclerosis, hypertension, diabetic vascular complications, and heart failure. The present study aimed to explore the effects of resistance training on plasma hydrogen peroxide level of ageing women. Methods: Twenty-four postmenopausal women (mean age = 67.37 ± 6.02, height = 153.02 ± 8.12, weight = 65.78 ± 12.03, BMI = 26.87 ± 4.16, body fat% = 18.61 ± 3.65, and WHR = 0.92 ± 0.4) were purposefully chosen and randomly divided into control and experimental groups each consisted of 12 subjects. Experimental group did resistance training for eight weeks as follows: three sessions per week with 40% to 65% intensity of a maximum repetition and 5% overload after each 6 sessions. Before and after 8 weeks of training, resting levels of hydrogen peroxide was measured and recorded. Data were analyzed by paired- samples t-test. Results: A statistically significant decrease observed in plasma H2O2 level (p= 0.041) and also weight (p= 0.048), body fat percent (p= 0.001), WHR (p= 0.037), resting- heart- rate (p= 0.021), systolic blood pressure (p= 0.006) and diastolic blood pressure (p= 0.002) of participants in experimental group but there were not any statistically different in any of the variables, pre and post-test in control group. Conclusion: Resistance training may be used as an intervention program for cardiovascular risk factors reduction