[Residual refractive errors following cataract surgery and its determinants]

To evaluate residual refractive errors after cataract surgery and its determinant factors at Farabi Eye Hospital, Tehran. Simple random sampling was done among cataract surgery scheduled patients over a 4 year period [2003-2006]. Exclusion criteria were uveitis, previous intraocular surgery and ocular trauma. After applying the exclusion criteria, 423 patients were studied. Lens calculation was performed using the SRK-II formula. Unexpected refractive errors were defined as the difference between postoperative refractive errors with target refraction. Mean and percentage of this variable were reported based on 0.5, 1 and 2 D of ametropia. Of 558 studied patients, 78.1% had biometric data before and refractive data after surgery. Mean absolute unpredictable refractive error was 0.84 +/- 0.89 D. Eyes with normal axial length [AL] had the least [0.76 +/- 0.84] and those with long AL had the most unpredictable refractive errors [P<0.001]. 45.9%, 73.9%, and 91.7% of the study cases had refractive errors within 0.5, 1 and 2 D of emmetropia, respectively. Eyes with short AL had positive refraction and those with long AL had negative refraction after surgery. The majority of keratometric astigmatism followed extra-capsular surgery while the least measures were associated with phacoemulsification [P<0.001]. Axial length was one of the important factors influencing residual refractive errors after cataract surgery. Unpredictable refractive errors were more common in eyes with long and short AL than those with normal AL

[Prevalence of amblyopia in school children in Mashhad]

To determine the prevalence of amblyopia and its determinants in students of region 1 in Mashhad, 2006. Using randomized cluster sampling, 2510 students were selected to undergo ophthalmologic examinations. Amblyopia was defined as corrected visual acuity of 8/10 or less in either eye. Of the 2510 selected student, 2150 were examined [85.6% participation rate]. The prevalence of amblyopia was 1.9% [95% confidence interval [CI], 0.94 to 2.9] including 2.1% in female and 1.7% in male subjects [P=0.620]. Amblyopia was detected in right eye in 31.7%, left eye in 41.5% and both eyes in 26.8%. About 66% of amblyopic cases had refractive errors. The prevalence of amblyopia in students of region 1 in Mashhad is comparable to that of other parts of the country. Refractive error is a significant risk factor for occurring amblyopia