Main visual symptoms associated with refractive errors and spectacle need in a Brazilian population

AIM： To determine the main visual symptoms in a Brazilian population sample, associated to refractive errors（REs） and spectacle need to suggest priorities in preventive programs.METHODS： A cross-sectional study was conducted in nine counties of the southeast region of Brazil, using a systematic sampling of households, between March 2004 and July 2005. The population was defined as individuals aged between 1 and 96 y, inhabitants of 3600 residences to be evaluated and 3012 households were included,corresponding to 8010 subjects considered for participation in the survey, of whom 7654 underwent ophthalmic examinations. The individuals were evaluated according their demographic data, eye complaints and eye examination including the RE and the need to prescribe spectacles according to age. Statistical analysis was performed using SPSS software package and descriptive analysis using 95% confidence intervals（P〈0.05）. RESULTS： The main symptom detected was asthenopia, most frequent in the 2ndand 3rddecades of life, with a significant decline after the 4thdecade.Astigmatism was the RE most associated with asthenopia. Reduced near vision sight was more frequent in those ≥40y with a progressive decline thereafter.Spectacles were most frequently required in subjects of≥40 years of age.CONCLUSION： The main symptom related to the vision was asthenopia and was associated to astigmatism. The greatest need for spectacles prescription occurred after40＇s, mainly to correct near vision. Subjects of ≥40years old were determined to be at high risk of uncorrected REs. These observations can guide intervention programs for the Brazilian population.

Evaluation of visual stress symptoms in age-matched dyslexic, Meares-Irlen syndrome and normal adults

AIM： To examine the prevalence of dyslexia and Meares-Irlen syndrome（MIS） among female students and determine their level of visual stress in comparison with normal subjects.·METHODS： A random sample of 450 female medical students of King Saud University Riyadh（age range, 18-30y） responded to a wide range of questions designed to accomplish the aims of this study. The detailed questionnaire consisted of 54 questions with 12 questions enquiring on ocular history and demography of participants while 42 questions were on visual symptoms. Items were categorized into critical and non-critical questions（CQ and NCQ） and were rated on four point Likert scale. Based on the responses obtained, the subjects were grouped into normal（control）, dyslexic with or without MIS（Group 1） and subjects with MIS only（Group 2）. Responses were analysed as averages and mean scores were calculated and compared between groups using one way analysis of variance to evaluate total visual stress score（TVSS =NCQ ＋CQ）, critical and non-critical visual stress scores. The relationship between categorical variables such as age, handedness and condition were assessed with Chi-square test.·RESULTS： The completion rate was 97.6% and majority of the respondents（92%） were normal readers, 2%dyslexic and 6% had MIS. They were age-matched. More than half of the participants had visited an eye care practitioner in the last 2y. About 13% were recommendedeye exercises and one participant experienced pattern glare. Hand preference was not associated with any condition but Group 1 subjects（3/9, 33%） were significantly more likely to be diagnosed of lazy eye than Group 2（2/27, 7%） and control（27/414, 7%） subjects. The mean±SD of TVSS responses were 63±14 and it was 44±9for CQ and 19 ±5 for NCQ. Responses from all three variables were normally distributed but the CQ responses were on the average more positive（82%） in Group 2 and less positive（46%） in Group 1 than control. With NCQ,the responses were equally less positive in Group 1 and2 than control. Group 2 subjects showed significantly higher TVSS（P =0.002）, NCQ（P =0.006） and CQ（P =0.008）visual stress scores than control but no difference between Group 1 and control subjects, was observed for all scores（P 〉0.05, for all comparisons）.·CONCLUSION： The prevalence of dyslexia and MIS among Saudi female students was 2% and 6%,respectively. Critical questions performed best for assessing visual stress symptoms in dyslexic and MIS subjects. Generally, students with MIS were more sensitive to visual stress than normal students but dyslexics were more likely to present with a lazy eye than MIS and normal readers.