- A diagnosis of primary open-angle glaucoma (POAG) suspect is established by the presence of one of the following conditions: a consistently elevated intraocular pressure (IOP), a suspicious-appearing optic nerve, or an abnormal visual field.
- Highlights of established risk factors for a POAG suspect diagnosis include an elevated IOP, family history of glaucoma or glaucoma suspect, thin central cornea, race, older age, myopia, and type 2 diabetes.
- The decision to treat a POAG suspect patient may depend on evidence of optic nerve changes, any visual field defect, level of IOP, and other associated risk factors.
- In the Ocular Hypertension Treatment Study (OHTS) overall, 90% to 95% of patients with ocular hypertension did not go on to develop glaucoma over 5 years, but treatment to reduce IOP also reduced the risk of developing POAG from 9.5% to 4.5%.
- A reasonable target for IOP reduction in a POAG suspect patient is 20%, based on the OHTS.
- Appropriate testing to evaluate and monitor patients with open-angle glaucoma (OAG) includes gonioscopy, pachymetry, tonometry, perimetry, careful observation of the optic nerve, and ocular imaging.
- If a decision is made to treat IOP, options include medical eye drops or laser trabeculoplasty.
Table 1. Recommendation Grading
|I||High-quality meta-analyses, systematic reviews of randomized controlled trials (RCTs), or RCTs with a very low risk of bias|
|I||Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias|
|I-||Meta-analyses, systematic reviews of RCTs, or RCTs with a high risk of bias|
|II||High-quality systematic reviews of case-control or cohort studies High-quality case-control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal|
|II||Well-conducted case-control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal|
|II-||Case-control or cohort studies with a high risk of confounding or bias and a significant risk that the relationship is not causal|
|III||Nonanalytic studies (e.g., case reports, case series)|
|G - Good quality||Further research is very unlikely to change our confidence in the estimate of effect|
|M - Moderate quality||Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate|
|In - Insufficient quality||Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Any estimate of effect is very uncertain|
|S - Strong recommendation||Used when the desirable effects of an intervention clearly outweigh the undesirable effects or clearly do not|
|D - Discretionary recommendation||Used when the trade-offs are less certain—either because of low-quality evidence or because evidence suggests that desirable and undesirable effects are closely balanced|
- To rate individual studies, a scale based on Scottish Intercollegiate Guideline Network (SIGN) is used.
- The body of evidence quality ratings is defined by Grading of Recommendations Assessment, Development and Evaluation (GRADE). GRADE is a systematic approach to grading the strength of the total body of evidence that is available to support recommendations on a specific clinical management issue.
- Key recommendations for care are defined by GRADE.
Visual Field Evaluation
- Eye care providers evaluate the visual field using automated static threshold perimetry (SAP) with white-on-white stimuli. It is the gold standard test for comparing other types of visual field testing. Careful manual combined kinetic and static threshold testing (e.g., Goldmann visual fields) is an acceptable alternative when patients cannot perform automated perimetry reliably or if it is not available. If visual field glaucomatous damage is newly detected in a glaucoma suspect patient, it is best to repeat the testing to confirm the changes. (II , G, S)
Optic Nerve Head and Retinal Nerve Fiber Layer Imaging
- The appearance of the optic nerve and, if possible, the retinal nerve fiber layer (RNFL), should be documented for the glaucoma suspect patient. (II , G, S)
Although they are distinctly different methodologies, stereoscopic disc photographs and computerized images of the nerve are complementary with regard to the information they provide the clinician who must manage the patient.
- In the absence of these methodologies, a nonstereoscopic photograph or a drawing of the optic nerve head (ONH) should be recorded, but this is a less desirable alternative to stereophotography or computer-based imaging. (III, In, S)
- Even though digital imaging technology is approved as an adjunct to aid in glaucoma diagnosis, the clinician should include all perimetric and other structural information when formulating patient management decisions. (III, In, S)