| Sumario: | Background: Symptoms in refractive, accommodative, and vergence anomalies are similar, which may pose some challenges with differential diagnosis. The aim of conducting this study was to explore associations among symptoms and refractive, accommodative, and vergence anomalies. Methods: Using a multi-stage random cluster sampling, 1211 children (481 males and 730 females) between 13 and 19 years of age, with a median age of 16 years, were selected. The preliminary visual functions evaluated included visual acuity, stereo-acuity, and suppression; refractive errors were measured objectively using the autorefractor and then refined subjectively. Other tests performed included measurement of accommodative (amplitude, accuracy, facility, and relative) and vergence functions (near point of convergence, heterophoria, and fusional vergences). Symptoms were evaluated using the Convergence Insufficiency Symptom Survey. Results: The prevalence of the respective refractive errors were: myopia (≥-0.50 D) 4.4%, hyperopia (≥+0.50 D) 4.8%, and astigmatism (≥-0.75 DC) 3.2%; the prevalence of anisometropia (≥±0.75 D spherical equivalent refraction between both eyes) was 1.3%. The prevalence estimates for accommodative anomalies were: accommodative infacility 12.9%, accommodative insufficiency 4.5%, and accommodative excess 2.8%. Accommodative infacility was associated with more symptoms than accommodative insufficiency, whereas accommodative excess was not associated with any symptoms. The prevalence estimates for convergence insufficiency were: low suspect 11.8%, high suspect 6%, definite 4.3%, and pseudo-convergence insufficiency 1.9%. The prevalence of convergence excess was 5.6%, and that of fusional vergence dysfunction was 3.3%. The mean symptom scores for pseudo-convergence insufficiency, convergence excess, and fusional vergence dysfunction were higher than those for any severity of convergence insufficiency. Overall, the mean symptom scores for accommodative insufficiency, infacility, and pseudo-convergence insufficiency were significantly higher than other anomalies. For all types of anomalies, the mean symptom scores for females were significantly higher than for males (p=0.001), older students were significantly higher than younger students (p=0.001), and higher grade levels were significantly higher than lower grade levels (p=0.001). Conclusion: Our findings suggest that astigmatism is the most symptomatic refractive error, while accommodative infacility, accommodative insufficiency, and pseudoconvergence insufficiency are the most symptomatic accommodative-vergence anomalies. Accommodative excess, convergence insufficiency, convergence excess, and heterophoria are least likely to produce symptoms. Female students are more likely to be symptomatic than males, as are students in upper school grade levels compared to students in lower grade levels. Identification of symptoms that are specific to each anomaly is useful for differential diagnosis and treatment.
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