[Prevalence and causes of blindness and visual impairment in varamin district]

To estimate the magnitude and causes of visual impairment [VI] in subjects aged >/= 50 years in Varamin district in 2009 using the proposed method by the World Health Organization [WHO]. This cross sectional population based survey was performed in Varamin targeting people over the age of 50 years using the proportional probabilities to size and cluster compact segment sampling method. Blindness was defind by WHO definition as best corrected visual acuity [VA] in the better eye less than 3/60. Severe visual impairment [SVI] and visual impairment [VI] were defined as 3/60

[Inferior oblique muscle recession versus myectomy for inferior oblique overaction]

To determine the effect of recession and myectomy on inferior oblique overaction [IOOA]. This study was performed on 50 patients [82 eyes] scheduled for IOOA surgery who were randomly divided into two groups: recession [R] versus myectomy [M]. A complete eye examination was performed before the operation. IO was cut off at its inferior temporal region when using M procedure. In the other group [R] after disinsertion, the IO muscle was sutured to 2mm lateral and 3.5 to 4mm posterior to the insertion of the inferior rectus. After at least 3 months, the same examinations were repeated. Successful surgery was defined as IOOA<+1. Twenty-five men [50%] and 25 women with the mean age of 12.3 +/- 5.9 [range 3-32] years entered the study. The surgery was performed in 18 patients unilaterally and in 32 patients bilaterally. Both myectomy and recession methods were successful in reducing IOOA [PM<0.001, PR<0.001]. The amount of IOOA reduction was 2.37 in the M group and 1.92 in the R group which was not significantly different [P=0.097, using Mann-Whitney test]; however, ordinal logistic regression showed a difference [P=0.016]. We found primary IOOA without superior oblique underaction [SOUA] in 28 eyes in the M group and in 32 eyes in the R group. Secondary IOOA with superior oblique underaction [SOUA] was found in 14 eyes in the M and in 8 eyes in the R group, respectively. In patients with more initial IOOA, the outcomes of both methods were better compared to patients with less initial overaction. There was no statistically significant difference in postoperative function of IO between these two methods of surgery [P=0.051]. Both methods resulted in equal improvements in SOUA and V-pattern. Complications included new hypertropia [2%], new DVD [dissociated vertical deviation] [8%] and asymmetry [2%]. Both recession and myectomy have significant weakening effect on IOOA. Myectomy results in more normal function of IOOA but IOUA is also higher with this method. Both methods are more effective if the initial overaction is higher

[High dose intravenous corticosteroid versus placebo in recent traumatic optic neuropathy]

To compare the effect of high dose intravenous corticosteroid therapy with placebo in the treatment of recent traumatic optic neuropathy [TON]. In double masked-placebo controlled clinical trial, 31 eyes of 31 patients were randomly assigned into two groups. Only patients with history of ophthalmic or head trauma within the past 7 days were included. Unconscious patients, with penetrating ocular injury, and candidates for decompression surgery were excluded. The treatment group [16 eyes] received 1 gr methylprednisolone intravenously for 3 days followed by 1 mg/kg prednisolone orally for 11 days. The placebo group [15eyes] received 50 ml normal saline intravenously every 6 hours for 3 days. Visual improvement was defined as increase of at least 0.3 logMAR visual acuity after 3 month. Visual improvement was achieved in 68.8% of the treatment group and 53.3% of the placebo group [P=0.1]. Visual improvement in the first 48 hours was correlated with final visual acuity [P=0.03] but final visual acuity was not significantly correlated with age [P0.06], interval from trauma to treatment [P=0.5], and initial visual acuity [P=0.06]. In patients with recent TON, high-dose intravenous corticosteroids and placebo are comparable in terms of improvement in visual acuity

[Corneal thickness changes after soft contact lens removal]

Purpose: to evaluate corneal thickness changes after soft contact lens [SCL] removal in LASIK candidates

Methods: fifty LASIK candidates [100 eyes] with history of daily wear SCL for at least 6 months were enrolled in this descriptive study. Central corneal thickness was measured by ultrasonic pachymetry immediately after lens removal and then repeated daily at the same time, until the thickness became stable

Results: subjects were aged between 18 to 40 years [mean, 29.5 years]. Central corneal thickness immediately after lens removal was 557.4 +/- 32 [micro]m and reached 521.8 +/- 25 [micro]m when corneal edema completely resolved. After discontinuation of SCL wear, corneal edema required 2-15 days to resolve. Corneal thickness stabilized in 74% within the 1 st week, in 24% during the 2nd week, and in 2% during the 3rd week. Older patients and more severe primary corneal edema needed longer time to recover. There was no significant correlation between sex and rate of corneal deswelling

Conclusion: it is important to discontinue SCL wear at least 15 days before refractive surgery for corneal thickness stabilization to achieve an accurate pachymetry