Abstract
Intraocular pressure (IOP) measured through the sclera has some advantages over IOP measured through cornea. This study aimed to determine the agreement between IOP as estimated by scleral Schiotz (SS) tonometer and Goldmann applanation tonometer (GAT). In this cross-sectional observational study, IOP was measured by GAT on cornea and Schiotz tonometer on temporal sclera. Axial length and central corneal thickness (CCT) were noted. GAT IOP was then estimated (eGAT) from SS IOP using a predictive formula. Agreement of GAT corrected for CCT (cGAT) with eGAT and SS IOP were assessed. The effects of age, axial length, refraction, CCT, gender, and ocular and systemic comorbidity on measured IOP were also assessed. The study included 155 patients with mean age of 54.27 ± 10.02 years. Mean IOP measured by GAT and scleral Schiotz were 16.58 ± 2.76 mm Hg and 16.10 ± 2.96 mm Hg respectively. The mean IOP by cGAT and eGAT were 16.70 ± 2.80 mm Hg and 17.07 ± 3.10 mm Hg respectively. Both eGAT & SS IOP had good agreement with cGAT on Bland-Altmann plot (p = 0.96; 0.51 respectively). Age, axial length, refraction, central corneal thickness, gender, and ocular and systemic comorbidity did not show significant correlation with IOP measurement. GAT IOP as estimated from SS IOP showed good agreement with measured GAT values. SS IOP also agreed well with GAT IOP. Clinical significance: IOP measurement on the sclera using Schiotz can be used as an alternative to GAT.