Glaucoma is a progressive optic neuropathy characterized by irreversible damage to the optic nerve due to elevated intraocular pressure (IOP), leading to gradual visual field loss. It is the second leading cause of blindness worldwide and is often asymptomatic in early stages.

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II. Classification of Glaucoma

1. Primary Glaucoma (No identifiable cause)

• Primary Open-Angle Glaucoma (POAG) – Most common type, slow progression
• Primary Angle-Closure Glaucoma (PACG) – Sudden IOP rise, medical emergency

2. Secondary Glaucoma (Due to underlying pathology)

• Neovascular Glaucoma – Associated with diabetes, retinal vein occlusion
• Pseudoexfoliative Glaucoma – Deposition of material on lens & trabecular meshwork
• Pigmentary Glaucoma – Pigment dispersion obstructing aqueous drainage
• Uveitic Glaucoma – Inflammation-induced trabecular meshwork dysfunction
• Traumatic Glaucoma – Due to blunt trauma or penetrating injuries

3. Congenital and Developmental Glaucoma

• Primary Congenital Glaucoma – Due to abnormal trabecular meshwork development
• Juvenile Open-Angle Glaucoma – Presents in late childhood/early adulthood

III. Risk Factors for Glaucoma

🔹 Elevated IOP (>21 mmHg) – Most important modifiable risk factor
🔹 Age > 40 years – Risk increases with age
🔹 Family history – Genetic predisposition (MYOC, OPTN gene mutations)
🔹 Thin central corneal thickness (CCT < 500 µm) – Higher risk of POAG
🔹 Diabetes & Hypertension – Increased vascular dysregulation
🔹 Steroid Use – Prolonged corticosteroid therapy

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IV. Pathophysiology of Glaucoma

1. Normal Aqueous Humor Dynamics

• Produced by ciliary body → Flows through posterior chamber → Passes via pupil → Drains through trabecular meshwork & Schlemm’s canal

2. Pathogenesis of Open-Angle vs. Angle-Closure Glaucoma

Type	Mechanism	Effect on IOP
Open-Angle Glaucoma (POAG)	Increased resistance in trabecular meshwork	Gradual rise in IOP
Angle-Closure Glaucoma (PACG)	Iris pushes forward, blocking aqueous outflow	Sudden IOP elevation (Medical Emergency)

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V. Clinical Features of Glaucoma

1. Symptoms Based on Glaucoma Type

Type	Symptoms
Open-Angle Glaucoma	Painless, gradual vision loss, peripheral field loss
Angle-Closure Glaucoma	Severe eye pain, headache, nausea, halos around lights, red eye
Congenital Glaucoma	Enlarged eyes (buphthalmos), tearing, photophobia

2. Signs of Glaucoma

✅ Elevated IOP (>21 mmHg)
✅ Optic Disc Changes – Cupping (cup-to-disc ratio > 0.6), notching
✅ Corneal Edema – In acute angle-closure glaucoma
✅ Visual Field Defects – Arcuate scotoma, nasal step, tunnel vision

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VI. Diagnostic Evaluation

1. Tonometry (IOP Measurement)

Method	Normal IOP Range	Clinical Use
Goldmann Applanation Tonometry (GAT)	10-21 mmHg	Gold standard for IOP
Non-contact (Air-Puff) Tonometry	12-22 mmHg	Screening tool
Rebound Tonometry	10-21 mmHg	Home monitoring

2. Gonioscopy (Angle Assessment)

• Open-angle glaucoma → Wide, normal angles
• Angle-closure glaucoma → Narrow/closed angles

3. Optical Coherence Tomography (OCT)

• Detects retinal nerve fiber layer (RNFL) thinning
• Identifies early glaucomatous changes before visual field defects

4. Visual Field Testing (Perimetry)

Defect Type	Clinical Significance
Arcuate Scotoma	Early glaucoma
Nasal Step	Classic finding in POAG
Tunnel Vision	Advanced glaucoma

5. Pachymetry (Corneal Thickness)

• Thin cornea (<500 µm) → Higher risk of glaucoma

6. Fundus Examination (Optic Nerve Head)

• Cup-to-Disc Ratio (C:D) > 0.6 → Glaucoma suspicion
• Vertical Notching of Disc → High specificity for POAG

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VII. Management of Glaucoma

1. Medical Management (IOP Reduction)

Drug Class	Mechanism	Examples
Prostaglandin Analogs	↑ Aqueous outflow	Latanoprost, Bimatoprost
Beta-Blockers	↓ Aqueous production	Timolol, Betaxolol
Alpha-Agonists	↓ Aqueous production & ↑ Outflow	Brimonidine, Apraclonidine
Carbonic Anhydrase Inhibitors	↓ Aqueous production	Acetazolamide, Dorzolamide
Miotics (Cholinergics)	↑ Trabecular outflow	Pilocarpine

2. Laser Procedures

Procedure	Indication
Laser Trabeculoplasty (ALT/SLT)	POAG, increases outflow
Laser Peripheral Iridotomy (LPI)	Angle-closure glaucoma
Cyclophotocoagulation	Refractory glaucoma

3. Surgical Management

Surgery	Indication
Trabeculectomy	Moderate-severe glaucoma
Tube Shunt Surgery	Refractory glaucoma
Minimally Invasive Glaucoma Surgery (MIGS)	Early-stage glaucoma

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VIII. Glaucoma Progression Monitoring

✅ IOP Monitoring – Target IOP depends on severity
✅ Visual Field Testing – Every 6 months
✅ OCT/RNFL Analysis – Detects progression before field loss

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IX. Summary & Key Takeaways

✅ Glaucoma is an irreversible optic neuropathy with gradual vision loss.
✅ Elevated IOP is a major risk factor but not always present.
✅ OCT & visual field testing are critical for early diagnosis.
✅ Prostaglandin analogs are first-line medical treatment.
✅ Laser & surgical options are used for refractory cases.

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Total Reading Time: 2 minutes 45 seconds