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Ophthalmology (Eye Conditions)

Glaucoma

A group of eye disorders characterized by progressive damage to the optic nerve, typically associated with raised intraocular pressure (IOP), leading to irreversible visual field loss and potential blindness. Includes open-angle and angle-closure types.

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Referral and warning signs

When to refer

Refer ALL suspected cases of glaucoma (based on IOP, disc appearance, symptoms, or screening) to an Ophthalmologist (RR) for definitive diagnosis and management. Acute Angle-Closure Glaucoma is an EMERGENCY requiring immediate referral.

Red flags

  • Sudden severe eye pain, blurred vision, halos, nausea/vomiting (AACG).
  • Markedly elevated IOP.
  • Progressive optic disc cupping or visual field loss on monitoring.
  • Suspicious optic disc appearance (large cup, asymmetry, notching, haemorrhage).

Signs and symptoms

  • Primary Open-Angle Glaucoma (POAG - Most Common):
  • - Usually asymptomatic in early stages.
  • - Gradual, painless loss of peripheral vision (tunnel vision) - often unnoticed until advanced.
  • - Difficulty adapting to dark.
  • - Optic disc cupping (increased cup-to-disc ratio) on fundoscopy.
  • - Elevated IOP (often, but not always - Normal Tension Glaucoma exists).
  • Acute Angle-Closure Glaucoma (AACG - Ophthalmic Emergency):
  • - Sudden onset of severe eye pain (often unilateral).
  • - Blurred vision / Halos around lights.
  • - Nausea and vomiting.
  • - Red eye (conjunctival injection).
  • - Corneal oedema (hazy cornea).
  • - Mid-dilated, fixed (non-reactive) pupil.
  • - Markedly elevated IOP (eye feels hard on palpation).
  • - Shallow anterior chamber.
  • Chronic Angle-Closure Glaucoma (CACG):
  • - May be asymptomatic or have intermittent symptoms (mild pain, blurred vision, halos).
  • - Progressive peripheral visual field loss.
  • - Gradual formation of peripheral anterior synechiae (iris adhering to cornea).
  • Congenital Glaucoma (Rare):
  • - Presents in infancy.
  • - Excessive tearing (epiphora).
  • - Photophobia.
  • - Blepharospasm (eyelid squeezing).
  • - Corneal haziness/oedema.
  • - Enlarged eye (buphthalmos).

Risk factors

  • POAG: Increasing age (>40-60), Black race, Family history of glaucoma, Elevated IOP, Thin central corneal thickness, Diabetes, Myopia, Hypertension (vascular factors).
  • Angle-Closure: Older age, Female gender, Asian ethnicity, Hyperopia (long-sightedness), Shallow anterior chamber, Family history.
  • Secondary Glaucoma: Eye trauma, Uveitis, Long-term steroid use, Eye surgery, Tumours, Diabetic retinopathy (neovascular glaucoma).

Diagnosis

Clinical assessment

POAG often detected during routine eye exam. AACG diagnosed based on acute symptoms/signs. Requires specialist evaluation.

Investigations

  • Ophthalmic Examination (Specialist):
  • - Visual Acuity.
  • - Intraocular Pressure (IOP) Measurement (Tonometry - e.g., Goldmann, Tonopen).
  • - Gonioscopy: Examines the drainage angle (to differentiate open vs closed angle).
  • - Dilated Fundus Examination: Optic Disc Assessment (cupping, neuroretinal rim thinning, asymmetry, haemorrhages).
  • - Visual Field Testing (Perimetry): Detects and monitors peripheral vision loss.
  • - Central Corneal Thickness (Pachymetry).
  • - Optical Coherence Tomography (OCT): Measures retinal nerve fibre layer thickness.

Diagnostic criteria

Characteristic optic nerve damage (cupping) and/or visual field loss, usually associated with elevated IOP (though not always). Gonioscopy differentiates open vs closed angle.

Management

Non-pharmacological management

  • Regular eye examinations for monitoring.
  • Patient education on chronic nature and importance of adherence.

Pharmacological treatment

  • Goal: Lower IOP to target level to prevent further optic nerve damage. Treatment is usually lifelong.
  • POAG / Chronic Angle-Closure (Medical Management First-line): (LOC: RR - requires specialist diagnosis/monitoring)
  • - Prostaglandin Analogues (PGAs): e.g., Latanoprost, Travoprost, Bimatoprost. (Once daily, effective, well-tolerated). First-line.
  • - Beta-blockers: e.g., Timolol 0.5%, Betaxolol. (BID, Caution: asthma, COPD, heart block, bradycardia).
  • - Alpha-adrenergic Agonists: e.g., Brimonidine. (BID/TID, Allergy common).
  • - Carbonic Anhydrase Inhibitors (CAIs): Topical (Dorzolamide, Brinzolamide - BID/TID) or Oral (Acetazolamide - used short-term for high pressure).
  • - Miotics (Pilocarpine): Less common now due to side effects.
  • - Combination drops often used.
  • Acute Angle-Closure Glaucoma (EMERGENCY Management): (LOC: H/RR)
  • - Immediate IOP Lowering:
  • - IV Acetazolamide 500mg.
  • - Topical Beta-blocker (e.g., Timolol 0.5%).
  • - Topical Alpha-agonist (e.g., Apraclonidine/Brimonidine).
  • - Topical Pilocarpine 1-2% (constricts pupil, opens angle - give AFTER IOP starts lowering).
  • - Systemic hyperosmotic agent (IV Mannitol 20% or Oral Glycerol) if needed.
  • - Definitive Treatment (after IOP controlled): Laser Peripheral Iridotomy (LPI) in BOTH eyes.
  • - Pain relief and antiemetics.

Monitoring

Regular monitoring of IOP, optic disc appearance, visual fields, and adherence/side effects. Frequency depends on severity and stability.

Complications

  • Progressive, irreversible visual field loss.
  • Blindness.
  • Complications of treatment (medication side effects, surgical complications).

Prevention

  • Regular comprehensive eye examinations, especially for high-risk individuals (age >40, family history, Black race) to allow early detection and treatment.
  • Prompt treatment of AACG.

Patient education

  • Explanation of glaucoma as chronic optic nerve damage, often linked to IOP.
  • Irreversible nature of damage - treatment aims to PREVENT further loss.
  • Importance of lifelong treatment adherence (eye drops).
  • Proper eye drop instillation technique.
  • Potential side effects of medications.
  • Need for regular follow-up appointments (lifelong monitoring).
  • Family history implications - advise relatives to get screened.

Uganda-specific notes

Glaucoma is a leading cause of irreversible blindness. POAG is common, often diagnosed late due to lack of symptoms and limited screening. Angle closure also occurs. Access to diagnostic equipment (tonometry, gonioscopy, visual fields, OCT) and treatment options (variety of drops, laser, surgery) is limited outside specialized centres.

Surgical / Laser Management

  • (Specialist procedures for POAG/CACG if medical therapy fails/intolerated or as primary):
  • - Laser Trabeculoplasty (SLT/ALT).
  • - Trabeculectomy (Filtering surgery).
  • - Glaucoma Drainage Devices (Shunts).
  • - Minimally Invasive Glaucoma Surgery (MIGS).
  • - Laser Peripheral Iridotomy (LPI) for angle closure.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 20, Section 20.2.2

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