Glaucoma
Concept anchors
Diagnosis rests on three pillars: intraocular pressure, optic disc/retinal nerve fibre layer structure and visual field. Gonioscopy is mandatory in every glaucoma workup - Shaffer grading, recognition of pigment, peripheral anterior synechiae and neovascularization. Disc features include increased cup-to-disc ratio, bayoneting, beta-zone atrophy, disc haemorrhage and retinal nerve fibre layer loss. Fields show arcuate defects, nasal steps, paracentral scotoma and eventually central sparing; use pattern deviation and glaucoma hemifield testing, and remember that field loss lags structural loss.
Management
Open-angle disease: prostaglandin analogues first-line (once daily, iris darkening, periorbital fat atrophy, eyelash lengthening), then beta-blockers (avoid in asthma and heart block), alpha agonists (avoid in young children due to apnea), carbonic anhydrase inhibitors and pilocarpine. Laser trabeculoplasty is increasingly first-line. Surgery includes trabeculectomy with mitomycin C, tube shunts and MIGS. Angle closure is managed acutely with pressure-lowering therapy, pilocarpine, corneal indentation and laser peripheral iridotomy; prophylactic iridotomy for the fellow eye.
Traps
Pupil block versus non-pupil block mechanisms, aqueous misdirection after surgery (myopic shift, flat anterior chamber, patent iridotomy), steroid response, and neovascular glaucoma needing anti-VEGF plus panretinal photocoagulation. Normal-tension glaucoma requires excluding other optic neuropathies.
Worked example
A painful red eye with mid-dilated fixed pupil, hazy cornea and pressure of 50 mmHg: treat medically first, then iridotomy once the cornea clears.