Glaucoma Diagnostic Procedures Diagnosing glaucoma requires more than a simple vision chart or a single pressure reading. Because early glaucoma causes no pain and gradually impairs side vision before central sight is affected, eye care specialists rely on a multi-step evaluation. A comprehensive diagnostic battery assesses internal eye pressure, drainage anatomy, optic nerve health, and visual function. Core Glaucoma Diagnostic Tests Procedure Clinical Name What It Evaluates Why It Is Essential Eye Pressure Check Tonometry Intraocular pressure (IOP) inside the eye. High IOP is the primary treatable risk factor for optic nerve damage. Goldmann applanation is considered the clinical gold standard. Drainage Angle Exam Gonioscopy The anterior chamber angle where the cornea meets the iris. Determines whether the eye’s fluid drainage system is w ide open, narrow, or completely blocked. Corneal Thickness Test Pachymetry Central corneal thickness measured in microns. Cornea thickness directly impacts IOP accuracy; thin corneas can cause artificially low pressure readings. Visual Field Mapping Perimetry Full range of peripheral (side) and central vision. Identifies blind spots (scotomas) before noticeable functional vision loss occurs. Procedure Clinical Name What It Evaluates Why It Is Essential Nerve Fiber Imaging Optical Coherence Tomography (OCT) High-resolution cross-sections of the retinal nerve fiber layer (RNFL). Catches microscopic structural thinning of the optic nerve long before field defects appear. Dilated Nerve Exam Ophthalmoscopy / Biomicroscopy Optic nerve head architecture and cup-to-disc ratio. Allows direct stereoscopic visualization to check for optic disc cupping, pallor, or hemorrhages. What to Expect During Your Evaluation Topical Drops: Numbing drops are administered for tonometry and gonioscopy to ensure comfort, followed by dilating drops to widen your pupils for a complete view of the retina and optic nerve. Non-Invasive Scans: OCT imaging and digital fundus photography are contact-free, quick, and completely painless. Interactive Testing: Visual field perimetry requires you to sit comfortably in a dim room and click a response button whenever flashes of light appear in your peripheral vision. Baseline Establishment: Results from these tests serve as a permanent digital benchmark, allowing your ophthalmologist to track structural stability or detect subtle progression during future follow-ups. A complete diagnostic workup is essential for catching optic nerve changes early, enabling targeted treatment to protect and maintain long-term vision.