What tests are required for glaucoma evaluation?

Diagnosing glaucoma requires a comprehensive ophthalmologic evaluation, as the condition often progresses silently without early symptoms. Key diagnostic tests include intraocular pressure (IOP) measurement via tonometry—typically using Goldmann applanation tonometry, which remains the clinical gold standard. Central corneal thickness (CCT) is also measured with pachymetry, since thinner corneas may underestimate true IOP and thicker corneas may overestimate it, both influencing glaucoma risk assessment.

Optic nerve head evaluation is critical and involves stereoscopic optic disc examination—preferably with a slit-lamp biomicroscope and 78- or 90-diopter lens—to assess cup-to-disc ratio, neuroretinal rim integrity, disc hemorrhages, and asymmetry between eyes. Optical coherence tomography (OCT) provides objective, quantitative analysis of retinal nerve fiber layer (RNFL) thickness and ganglion cell complex, detecting structural damage before functional loss occurs.

Visual field testing—most commonly using automated perimetry (e.g., Humphrey Visual Field Analyzer with SITA or ZEST algorithms)—assesses functional deficits, such as arcuate scotomas, nasal steps, or paracentral defects. Baseline and serial testing are essential for monitoring progression. Gonioscopy is performed to evaluate the anterior chamber angle anatomy, distinguishing open-angle from angle-closure glaucoma and identifying secondary causes like synechiae or pigment dispersion.

Additional assessments may include corneal hysteresis (via ocular response analyzer), anterior segment OCT for angle imaging, fundus photography for longitudinal comparison, and, in select cases, electrophysiologic testing or advanced imaging modalities. A thorough patient history—including family history of glaucoma, systemic conditions (e.g., hypertension, diabetes, migraines), medication use (especially corticosteroids), and prior ocular trauma or surgery—is integral to accurate diagnosis and personalized management.