The Comparison of Ocular Characteristic between Major Thalassemia and Healthy Group

Abstract

Purpose: To determine and compare ocular characteristics and refractive errors between thalassemia major patients and normal subjects. Methods: In this study, 71 thalassemia major patients and 79 age and sex matched healthy subjects that were selected in an ongoing manner underwent complete optometric and ophthalmic examinations including auto refraction, subjective refraction, fluorescein tear break- up time, and pachymetry after anthropometric measurements. Results: The results showed that the mean UCVA was better in the control group versus the thalassemia group (p<0.001) while there was no difference in BCVA between the two groups (p=0.416). Moreover, the mean spherical equivalent was 0.38±0.13 D less in the thalassemia group compared to the control group (p=0.007) while corneal power (p<0.001) and cylinder power (p=0.001) were larger in thalassemia patients. Most common type of astigmatism was against the rule pattern in thalassemia patients and with the rule pattern in the control group (p<0.001). The mean tear break-up time was 11.35 ± 6.43 in the thalassemia group and 14.63 ± 5.79 in the control group (p=0.001), and the mean near point of accommodation (NPA) (p=0.009) and near point of convergence (NPC). (p=0.003) were significantly smaller in the thalassemia group compared to the control group. Conclusion: These patients suffer from a myopic shift due to exaggerated responses to changes in ocular growth, dry eye secondary to goblet cell loss, and a higher prevalence of vertical astigmatism due to eyelid laxity and pressure on the cornea. Therefore, regular ophthalmological evaluations are highly recommended in these patients.

Keywords

• beta-thalassemia
• ocular characteristic
• refractive errors
• cohort study