What is a Glaucoma Suspect?
A glaucoma suspect is an individual with clinical findings or risk factors indicating an increased likelihood of developing primary open-angle glaucoma (POAG), but who does not yet have definitive evidence of glaucomatous optic nerve damage or visual field loss. 1
Diagnostic Criteria
A patient receives a glaucoma suspect diagnosis when they have an open anterior chamber angle on gonioscopy AND meet any one of the following three criteria in one or both eyes: 1
- Elevated intraocular pressure (IOP) >21 mmHg with normal-appearing optic disc, retinal nerve fiber layer (RNFL), and visual field 1
- Suspicious optic nerve head or RNFL appearance suggesting possible glaucomatous damage without confirmed visual field defects 1
- Visual field abnormalities suspicious for glaucoma in the absence of other optic neuropathy or retinopathy 1
This definition explicitly excludes angle-closure glaucomas and secondary open-angle glaucomas from known causes such as pseudoexfoliation syndrome, pigment dispersion syndrome, and traumatic angle recession. 1
Epidemiology and Clinical Significance
The prevalence of ocular hypertension (IOP >21 mmHg without optic nerve damage) alone is 4.5% in non-Hispanic whites aged 40+ years and 3.5% in Latinos aged 40+ years in the United States. 1 Approximately 3-6 million Americans have ocular hypertension, with 75% remaining undiagnosed. 1
Critical clinical context: In the Ocular Hypertension Treatment Study, 90-95% of untreated glaucoma suspects did NOT progress to glaucoma over 5 years, but IOP-lowering treatment reduced progression risk from 9.5% to 4.5%. 1 This means most suspects will never develop glaucoma, making risk stratification essential to avoid overtreatment.
Risk Factors for Progression
The American Academy of Ophthalmology identifies these established risk factors for progression from suspect to POAG: 1
- Elevated IOP (strongest modifiable risk factor) 1
- Older age 1
- African race or Latino/Hispanic ethnicity 1
- Family history of glaucoma 1
- Thin central cornea 1
- Type 2 diabetes mellitus 1
- Myopia 1
- Low ocular perfusion pressure 1
- Disc hemorrhage 1
- Large cup-to-disc ratio 1
Required Evaluation and Monitoring
Essential baseline testing for all glaucoma suspects includes: 1
- Gonioscopy (mandatory to confirm open angle and exclude angle-closure) 1, 2
- Pachymetry (central corneal thickness measurement) 1
- Tonometry (IOP measurement) 1
- Perimetry (visual field testing) 1
- Detailed optic nerve examination with documentation 1
- Ocular imaging (OCT and/or stereoscopic photography provide complementary information) 1
Monitoring frequency: The American Academy of Ophthalmology recommends evaluation every 12-24 months for low-risk suspects, with more frequent monitoring for high-risk patients. 2
Treatment Considerations
The decision to treat depends on: 1
- Level of IOP elevation
- Number and severity of risk factors present
- Evidence of structural or functional changes suggesting early POAG development
- Patient life expectancy and quality of life considerations
When treatment is initiated, the target IOP reduction is 20% from baseline, based on OHTS data. 1 Treatment options include topical IOP-lowering medications or laser trabeculoplasty. 1
Common Pitfalls
Avoid these diagnostic errors:
- Failing to perform gonioscopy—this is mandatory to distinguish open-angle from angle-closure mechanisms 1, 2
- Diagnosing glaucoma suspect in patients with secondary causes (pseudoexfoliation, pigment dispersion, trauma) 1
- Treating all suspects—remember that >90% will not progress without treatment 1
- Using IOP >21 mmHg as the sole criterion without assessing other risk factors 1
Key clinical pearl: The diagnosis of glaucoma suspect is fundamentally about risk stratification, not disease presence. The goal is identifying who needs closer monitoring or preventive treatment versus reassurance, balancing the small risk of progression against treatment burden and side effects. 1