The Postural changes in intraocular pressure in normal and glaucomatous eyes in Indian population

Abstract

Introduction: Intraocular pressure (IOP) increases when changing from sitting to supine position flat without pillow with an average difference of 0.85 to 6.01mm of Hg. These postural changes of IOP have been found in normal persons, patients with ocular hypertension and normal tension glaucoma. The eye is relatively non-distensible, even small changes in the volume of aqueous humor may significantly change IOP. The increase in resistance in aqueous flow is thought to be the reason for higher IOP in supine compared to sitting position. The aim of this study is to analyze the Postural changes in intraocular pressure in normal and glaucomatous eyes of Indian population. Method: It was a prospective cross sectional study done in Armed Forces Medical College Pune, between June, 2022 to June, 2024 with sample sized of 60 people 30 controls (Normal) and 30 Primary open angle glaucoma). Patients underwent complete ocular examination. Two drops of Topical 2% propacaine were instilled. IOP measurements were taken by Parkin handheld tonometer in sitting and supine flat without pillow and supine with pillow positions at 10 minutes, 20 minutes and 30 minutes interval respectively. Results: The IOP difference between the sitting and supine flat position was significantly higher in the POAG than non-glaucoma subjects (5.0667±0.09 vs 6.01±0.85 mm Hg, P<0.001). The IOP difference between the sitting and supine with pillow positions was 1.3667±0.14 mm Hg for POAG and 2.8±0.34 mm Hg in non-glaucoma (P<0.001), While difference between supine flat and supine with pillow positions was 3.7±0.23 mm Hg in POAG and 3.2±0.51 mm Hg in non-glaucomatous patients (P<0.001). Conclusions: The rise in IOP due to change of posture from sitting to supine positions was significantly higher in glaucomatous patients.