Glaucoma Evaluation and Management
Core concepts
Know the diagnostic components: intraocular pressure, optic nerve head appearance (cup-to-disc ratio, neuroretinal rim, disc hemorrhage), visual field testing (Humphrey patterns such as arcuate scotoma, nasal step), and gonioscopy (open versus closed angle). Understand the difference between open-angle and angle-closure glaucoma, and between primary and secondary forms. Know the mechanism of action and side effects of each medication class, and the indications for laser therapy (SLT, LPI) and surgery.
Traps
Questions often confuse which field defect is classic for glaucoma: arcuate scotoma and nasal step are typical, while central scotoma is more characteristic of optic neuritis or macular disease. Remember that optic disc cupping can occur in other neuropathies, so the diagnosis requires correlation. Do not assume a normal IOP excludes glaucoma; normal-tension glaucoma exists.
Worked rule of thumb
Use the "IOP plus disc plus field" triad. A patient with a cup-to-disc ratio of 0.7, an arcuate defect, and IOP of 24 mmHg likely has primary open-angle glaucoma. If gonioscopy shows a narrow angle with a shallow anterior chamber, consider angle-closure and perform prophylactic laser peripheral iridotomy in the fellow eye.