Uncorrected Refractive error is an avoidable cause of visual impairment especially among children. Uncorrected refractive error is one of the important causes of amblyopia that exposes children to poor school performance. In this young population, amblyopia had caused severe unilateral impairment of vision 10 times more frequently than all other diseases and trauma This in later adulthood may refrain them from working resulting in severe social and economic losses. It is difficult to assess the frequency of amblyopia in the general population. Increased attention paid in recent years by the media and medical community to early detection of uncorrected refractive error has decreased the prevalence of amblyopia. So early detection and treatment of uncorrected refractive error remains ideal goals to strive for, as documented by this study and other population-based studies. Context: Uncorrected refractive error is one of the important causes of amblyopia among young children’s and if not detected timely, may lead to deterioration of quality of life and other psychosocial difficulties to children affecting individual’s self-image, work, school and friendship. Aims: To determine the prevalence and pattern of uncorrected refractive error in school going children and to study association between degree of anisometropia and severity of amblyopia. Settings and Design: Hospital based cross sectional study carried on 500 school going children up to 10th grade selected by non-probability convenient sampling according to the inclusion and exclusion criteria. Methods and Material: The clinical profile of these children was evaluated in department of ophthalmology, P.D.U Govt. medical college, Rajkot and they underwent detail visual assessment and ophthalmic examinations including measurement of uncorrected visual acuity, best corrected visual acuity, auto-refraction, retinoscopy, subjective correction and detailed squint evaluation, if present. during period of November 2019 to February 2021 under school health programme. All selected school going children were referred from different schools after primary screening at school as a part of school health programme. Valid informed consent was taken from patient’s parents/ guardians.If uncorrected vision was <6/12 in either eye, the child was declared to have defective vision. Statistical analysis used: We estimated prevalence of uncorrected refractory error using parametric methods and bivariate type of analysis. To validate the data, we calculated frequencies, percentage and their 95% confidence interval. Statistical association was done using chi-square test and p-value was determined. Results: Total of 500 school going children were enrolled in the study, out of which 221(44.2%) were females and 279 (55.8%) were males. The mean age of children was 9.81± 2.72 years (range, 6 to 14). The prevalence of uncorrected refractive error was 28% (140 children out of 500 children). Astigmatism was most common refractive error with prevalence of 73.57% (n=103) (95% CI, 3.12-6.54). The prevalence of myopia and hyperopia in our study was 15% (n=21) (95% CI, 5.34-5.45) and 11.2% (n=16) (95% CI ,2.37-2.78) respectively. Girls were more often myopic as well as hyperopic than boys which was statistically significant (p=0.031). Approximately 93.2% (n=96) (95%CI, 2.14-5.89) patients were having small astigmatism (0.5D-1.5D), while remaining 6.8% (n=7) (95% CI, 1.78-3.45) had high astigmatism (≥ 1.5D). There was no statistically significant difference between gender(p=0.67) and age groups (p=0.41) in case of high or low astigmatism. 80.58% (n=83) (95% CI, 2.18-3.56) patients had with the rule astigmatism, while 19.42% (n=20) (95% CI, 1.67-3.44) patients had against the rule astigmatism. With advancing age WTR astigmatism shows an increasing trend while ATR astigmatism shows a decreasing trend. In our study, prevalence of amblyopia was 8% and Hypermetropia was the most common refractive error 66.67% (n=20) (95% CI, 3.11-5.14) in amblyopic eyes followed by Myopia 20% (n=6) (95% CI, 2.12-4.78) in anisometropic and ametropic amblyopia. 13.33% patients (n=4) had meridional amblyopia. Children with mild to moderate degree of amblyopia were seen more in hyperopia comparison to myopic patients and the difference was statistically significant(p=0.03). Only one patient had severe unilateral amblyopia due to anisomyopia of > 6D spherical equivalent. In our study, we found depth and prevalence of amblyopia increased as the degree of anisometropia increased and it was found to be statistically significant(p=0.045). Conclusions: The following study highlights that prevalence of refractive error among school going school children is very high and uncorrected refractive error is now emerging to be commonest cause of amblyopia among school going children.Early detection of amblyopia and institution of appropriate therapy is of immense value towards preventing the prevalence of life long visual morbidity due to uncorrected refractory error. The data in the present study could be used to enhance screening efforts in an organised manner in those health-care groups which come in regular contact with infants and young children. This includes village health workers, personnel at mother and child care clinics, paediatricians both in practice and in referral hospital services and general practitioners associated with school health programmes. They could also be trained to assess visual acuity in very small children with Cardiff or Teller's visual acuity charts. Providing spectacles at a low and affordable cost to school going children as a part of school health programmer can prevent a major proportion of visual impairment.