Objective: To compare the effect of feeding human milk as opposed to formula and human milk on refractive error in preschool children aged 3 to 6 years.

Material and Methods: One hundred and seventy six eyes of 88 children were evaluated. According to the feeding pattern, the patients who fed only breast-fed were classified as Group I, and the patients who fed with combination of breast-fed and formula were classified as Group II. Results were retrospectively compared between groups.

Results: A total of 88 children undergone detailed ophthalmological examinations, of which 40 (45.5 %) were males and 48 (54.5 %) were females. Maternal birth age of 27.3% (n=24) of the children included in the study was over 30 years and birth weight of 96.6% (n=85) was over 2500 grams.

The mean ± standard deviation of the spherical, cylindrical and spherical equivalent (SE) values were 1.61±1.46 D; -0.98 ± 0.69 D and 1.12±1.43 D in group I and 1.00±2.57 D; -0.90 ± 0.81 D and 0.55 ± 2.72 D in group II, respectively (p=0.507 for spherical; p=0.299 for cylindrical and p=0.799 for SE). Although myopic refraction was less common in the breastfed group, there was no significant difference in myopic refraction between the groups (p= 0.507).

Conclusion: In conclusion, mean refractive error were different according to feeding pattern, but this study did not show significant differences between groups (p<0.050). There is a need to confirm this finding by performing more studies with a larger sample sizes.

Keywords: Breastfeeding, human milk, preschooler, refractive errors