فهرست مطالب ashkan shahnazi

To evaluate and modify the Randleman Ectasia Risk Score System for predicting post-laser in situ keratomileusis (LASIK) ectasia in patients with normal preoperative corneal topography. In this retrospective study we reviewed data from 136 eyes which had undergone LASIK including 34 ectatic and 102 normal eyes between 1999 and 2009. After determining the sensitivity and specificity of the Randleman system, a modified model was designed to predict the risk of post-LASIK corneal ectasia more accurately. Next, the sensitivity and specificity of this modified scoring system was determined and compared to that of the original scoring system. In our sample, the sensitivity and specificity of the Randleman system was 70.1% and 50.5%, respectively. Our modified model included the following parameters: preoperative central corneal thickness, manifest refraction spherical equivalent, and maximum keratometry, as well as the number of months elapsed from surgery. Sensitivity and specificity rates of the modified system were 74.2% and 76.2%, respectively. The difference in receiver operating characteristic curves between the Randleman and modified scoring systems was statistically significant (P<0.001). The best sensitivity and specificity for our model occurred with a cumulative cutoff score of 4.00; a low risk was considered if the score was ≤4.00, and high risk was defined with a score > 4.00. Our modified ectasia risk scoring system for patients with normal corneal topography can predict post LASIK ectasia risk with acceptable sensitivity and specificity. However, there are still unidentified risk factors for which further studies are required.

This study was conducted to identify the determinants of protective behavior in relation to HIV transmission. Since the risk of transmission is higher among those who have extramarital intercourse, the study sample constituted of such people. We started this study in 2010 and finished it in 2011. Participants were divided into low-risk and high-risk groups. High-risk people included sex workers and those who presented at drop-in centers. Interviewees were 18 men and women in the low-risk group and 12 men and women in the high-risk group. Data were collected through in-depth interviews and were analyzed using the thematic framework method. In both groups, protective behavior was influenced by willingness to protect, intention or decision to protect, and personal, social, and environmental barriers and facilitators. In terms of willingness, behavior was influenced to preserve sexual pleasure by avoiding condoms. In terms of barriers and facilitators, trust in partner, misperceptions, condom inaccessibility, unplanned sex, fear of contracting the disease, partner’s wish, ethical commitments were mentioned by both groups, stigma of condom possession by the low-risk group, and partner’s force was mentioned by the high-risk group. Educational programs need to focus on changing the concept that “condoms reduce sexual pleasure”. In addition, interventional programs to strengthen factors such as self-efficacy, ethical commitments, faithfulness, and correct beliefs such as undue trust in partner, misconception of being safe, unplanned sex, and the stigma of possessing condoms can be very effective in changing high-risk sexual behavior.

To determine the association between astigmatism and spherical refractive error in a clinical population In this cross-sectional study, 2,000 patients who presented to our optometry clinic were enrolled. All were tested for objective refraction with a Nidek AR-310A auto refractometer, and non-cycloplegic refraction. For those under 15 years of age, cycloplegic refraction was measured as well. Myopia and hyperopia were defined as a spherical power of -0.5 Diopter (D) or less and +0.5 D or greater, respectively. Astigmatism was defined as a cylinder power of ≥-0.5 D; with-the-rule (WTR) astigmatism if the steep axis was 0±20°, against-the-rule (ATR) astigmatism if the steep 90±20°, and oblique if the axis was in between. The mean age of the participants in this study was 31.52±18.39 years, and 910 (45.5%) were male. The Mean cylinder power of the subjects with high myopia and high hyperopia was 1.92±0.25 and 1.48±0.19 D, respectively. The lowest prevalence of astigmatism was found in subjects with emmetropia (P<0.001). There was an age-related decrease in the prevalence of WTR astigmatism, and an increase in ATR and oblique astigmatism (P<0.001). Mean cylinder error in WTR, ATR, and oblique astigmatism groups was 1.59±1.24, 1.10±0.76, and 1.16±0.04 D, respectively (P<0.001), and absolute mean spherical error was 1.97±2.03, 1.49±1.54, and 1.68±1.71 D, respectively (P<0.001). The results of this study indicated an association between astigmatism and spherical refractive error. Higher amounts of astigmatism were seen in subjects with high spherical ametropia. Astigmatism axis was related to the cylinder and spherical powers which were both higher in subjects with WTR than those with ATR and oblique astigmatisms. In those with ATR astigmatism with the refractive status was close to emmetropia.

This study was performed in order to characterize the psychometric properties of the National Eye Institute visual functioning questionnaire in Iranians. After forward and backward translation, examination of the translation quality and a pilot test, 80 patients with various chronic ophthalmic diseases and 30 healthy individuals completed the questionnaire. Internal consistency (IC) was measured using Cronbach's alpha coefficient and reproducibility was evaluated using the intraclass correlation coefficient (ICC) obtained through test-retests. Regarding construct validity, convergent, discriminant and known group comparison validities were evaluated. The standardized response mean index was used to assess responsiveness and sensitivity of the instrument to changes. Cronbach’s alpha was above 0.7 for all of the subscales except for that of “driving”, which had a value of 0.68. The ICC in all subscales was above 0.7. All items had correlations higher than 0.4 with their original subscales. About 70% of the items were correlated with their own subscale more than other subscales. Known group comparison showed that the healthy group scored significantly higher than the patients in all subscales and the composite score (P<0.001). Standardized response means ranged from 0.61 to 2.42, and was 1.19 in general health (GH), indicating the sensitivity of the instrument to changes. The Persian version of the National Eye Institute visual functioning questionnaire 25 was valid, reliable, responsive to changes and could evaluate the results of therapeutic ophthalmic interventions and quality of life (QoL) of the Iranian patients.