Ocular Pathology

General Ocular Pathology - Inflammatory Insights

• Cardinal Signs: Rubor, tumor, calor, dolor, functio laesa.

• Types:

  • Acute: PMNs, exudative (e.g., bacterial keratitis).
  • Chronic: Lymphocytes, macrophages, proliferative (e.g., chronic uveitis).
  • Granulomatous: Epithelioid cells, giant cells (e.g., sarcoid uveitis, TB).
    • Key cells: Langhans giant cells.

• Mediators: Prostaglandins (PGs), leukotrienes, histamine, cytokines (TNF-α, ILs).

  • PGs: Miosis, pain, ↑ vascular permeability.

• Cellular Players:

  • Neutrophils: Acute bacterial.
  • Lymphocytes/Plasma cells: Chronic, viral.
  • Eosinophils: Allergy, parasites.
  • Macrophages: Phagocytosis, chronic.

• Sequelae: Synechiae, cataract, glaucoma, phthisis bulbi.

⭐ Sympathetic ophthalmia is a bilateral granulomatous panuveitis following penetrating ocular trauma to one eye.

Corneal & Lens Pathologies - Clarity Compromised

• Corneal Clouding:
  • Keratitis (Inflammation):
    • Bacterial: Hypopyon, contact lens wear.
    • Viral: HSV (dendritic ulcer), HZO (pseudodendritic).
    • Fungal: Satellite lesions, feathery edges.
    • Acanthamoeba: Ring infiltrate, severe pain.
  • Dystrophies (Inherited, bilateral):
    • Fuchs: Endothelial decompensation, guttata.
    • Lattice: Amyloid deposits.
    • Granular: Hyaline deposits.
    • Macular: Mucopolysaccharide. 📌 AR, most severe.
  • Keratoconus: Conical protrusion, Fleischer ring, Munson's sign.
• Lens Opacification (Cataract):
  • Types: Senile (Nuclear sclerosis, Cortical spokes, PSC), Congenital (e.g., Rubella), Traumatic (Rosette), Metabolic (Galactosemia - oil droplet).
  • Ectopia Lentis: Displaced lens (e.g., Marfan - superotemporal, Homocystinuria - inferonasal).

⭐ Posterior Subcapsular Cataract (PSC) is common with chronic steroid use and causes early, significant glare.

Retinal & Uveal Pathologies - Vision Vanquishers

• Retinal Vascular Diseases:
  • Diabetic Retinopathy (DR):
    • NPDR: Microaneurysms, hemorrhages, exudates, Cotton Wool Spots (CWS).
    • PDR: Neovascularization (NVD/NVE), vitreous hemorrhage, tractional RD.
  • Hypertensive Retinopathy: Arteriolar narrowing, AV nipping, CWS, flame hemorrhages, macular star, papilledema (Grade IV).
  • Retinal Vein Occlusion (RVO):
    • CRVO: "Blood & thunder" fundus, sudden painless vision loss.
    • BRVO: Sectoral hemorrhages.
  • Retinal Artery Occlusion (RAO):
    • CRAO: Sudden, profound, painless vision loss; "cherry-red spot". Ocular emergency!
• Retinal Degenerations:
  • Age-related Macular Degeneration (AMD):
    • Dry (Atrophic): Drusen, RPE atrophy. Gradual vision loss.
    • Wet (Exudative): Choroidal neovascularization (CNVM), leakage. Rapid, severe vision loss.

*   Retinitis Pigmentosa (RP): Progressive nyctalopia, peripheral field loss, "bone spicule" pigmentation. 📌 Mnemonic: RP = Rods Perish.

• Ocular Tumors:
  • Uveal Melanoma: Most common primary intraocular tumor in adults. Liver metastasis common.
  • Retinoblastoma: Most common in children. Leukocoria, strabismus.

    ⭐ Retinoblastoma: Associated with Rb1 gene mutation. Histopathology shows Flexner-Wintersteiner rosettes.

Glaucoma & Optic Neuropathies - Pressure Problems

• Glaucoma: Optic neuropathy; characteristic disc cupping & visual field (VF) loss. Often associated with ↑ Intraocular Pressure (IOP).
  • Primary Open-Angle Glaucoma (POAG): Most common, chronic, painless. Due to trabecular meshwork dysfunction.
  • Angle-Closure Glaucoma (ACG): Iris obstructs trabecular meshwork. Acute (painful, red eye, halos, nausea) or chronic.
• Pathophysiology: ↑IOP → mechanical stress/vascular compromise at optic nerve head → Retinal Ganglion Cell (RGC) death → optic disc cupping (Cup-to-Disc Ratio > 0.5), characteristic VF defects.
• Risk Factors: Age, family history, ethnicity (African/Hispanic for POAG, Asian for ACG), myopia (POAG), hypermetropia (ACG), diabetes, prolonged steroid use.
• Diagnosis: Tonometry (IOP measurement), gonioscopy (angle assessment), optic disc exam, perimetry (VF testing).

  ⭐ Normal IOP is 10-21 mmHg. In acute angle closure glaucoma, IOP can rapidly rise, often exceeding 50 mmHg.

• Other Optic Neuropathies:
  • Ischemic Optic Neuropathy (ION): Arteritic (AION - e.g., Giant Cell Arteritis, ESR↑, urgent steroids) & Non-Arteritic (NAION - common, vasculopathic risks like DM, HTN).
  • Optic Neuritis: Inflammation, often Multiple Sclerosis-associated; pain on eye movement, ↓vision, Relative Afferent Pupillary Defect (RAPD).
  • Compressive/Infiltrative: Tumors, thyroid eye disease.

High‑Yield Points - ⚡ Biggest Takeaways

• Basal cell carcinoma: most common malignant eyelid tumor; locally invasive, rarely metastasizes.
• Retinoblastoma: RB1 gene; most common childhood intraocular malignancy; leukocoria, Flexner-Wintersteiner rosettes.
• Uveal melanoma: most common adult primary intraocular malignancy; liver metastasis is frequent.
• Chalazion: chronic lipogranulomatous inflammation of a Meibomian gland (blocked duct).
• Pterygium: elastotic degeneration of collagen, fibrovascular growth from conjunctiva, linked to UV exposure.
• Diabetic retinopathy: microaneurysms (earliest sign); neovascularization (proliferative DR).