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 wide 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. |
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.