Intraocular pressure and its association with ocular biometrics in Iranian children

To determine the mean value and normative distribution of intraocular pressure (IOP) in children and their association with demographic and ocular biometrics.

Cluster sampling was done to select the students in urban areas of Shahroud, northeast Iran, while all students living in rural areas were selected. IOP was measured in mmHg using a non-contact tonometer, along with corneal and retinal imaging and ocular biometric measurement.

After applying the exclusion criteria, 9154 eyes of 4580 students were analyzed, of whom 2377 (51.9 %) were boys. The mean age of the participants was 12.35±1.73 years (range: 9-15 years). The mean IOP was 15.58±2.83 (15.47-15.69) in total, 15.31±2.77 (15.17-15.46) in boys, and 15.88±2.86 (15.73-16.03) in girls (p < 0.001). The mean IOP was 15.07 and 15.49 in students aged 9 and 15 years, respectively. The mean IOP was 15.7 ± 2.64 (15.58-15.81) in urban and 14.52±4.05 (14.27-14.77) in rural students (p < 0.001). In the multiple generalized estimating equation model, IOP had a positive association with female sex (β=0.84, P < 0.001), systolic blood pressure (β=0.02, P < 0.001), cup volume (β=0.99, P < 0.001), corneal thickness (β=0.04, P < 0.001) and anterior chamber volume (β=0.007, P < 0.001) and a negative association with living in the rural area (β=-0.65, P < 0.001), rim area (β=-0.39, P < 0.001), and corneal diameter (β=-0.18, P = 0.045). Furthermore, individuals with myopia exhibited a significantly higher IOP (β=0.35, P < 0.001) compared to those with emmetropia.

This study showed the normative distribution of IOP and its associated factors in children. The results can be used in diagnosis and management of glaucoma.