Correlative Study of Central Corneal Thickness and Intraocular Pressure with Optic Disc Changes in Primary Open-Angle Glaucoma

Abstract

Background: Primary open-angle glaucoma (POAG) is characterised by open angles, raised intraocular pressure (IOP) and optic disc changes. Undetected glaucoma is the third leading cause of blindness. The study aims to correlate central corneal thickness and IOP with optic disc changes in POAG and to aid in the early detection and timely management of glaucoma to prevent advanced damage and vision loss. Methods: In this hospital-based prospective observational study, 50 cases (100 eyes) of POAG were selected after applying the inclusion and exclusion criteria. Detailed history, ocular examination, visual acuity testing, slit-lamp examination, gonioscopy, ultrasound pachymetry for central corneal thickness (CCT), IOP with Goldmann Applanation Tonometry (GAT), fundus examination with +90D lens and visual fields on Humphrey’s automated field analyser were performed for all patients. Results: There was a statistically highly significant positive correlation between IOP and CCT in the right and left eyes (P < 0.01). There was a statistically very highly significant difference between mean IOP and mean corrected IOP in the right eye and left eye also (P < 0.001). There was a statistically very highly significant difference in IOP, CCT and fundus cup-to-disc ratio (CDR) with HAP staging (P < 0.001). Conclusions: IOP was positively related to CCT. Thinner CCT <510μm eyes are at greater risk for more advanced disc cupping. Disc cupping increased proportionately with the rise in IOP. Thinner corneal readings should alarm the ophthalmologist to evaluate the patient thoroughly for glaucoma and monitor follow-up to keep a check on possible progression.

Keywords

• central corneal thickness (cct)
• intraocular pressure (iop)
• optic disc changes
• primary open-angle glaucoma (poag)