- Glaucoma is the MC cause of blindness in developed countries (in India/ World: Cataract).
Visual field defects in glaucoma:
- Earliest visual field defect in glaucoma: Isopter contraction
- Earliest visual field defect in primary open angle glaucoma: isopter contraction
- Earliest visually significant visual field defect in glaucoma: Paracentral scotoma
- First visual field affected in glaucoma: Superior (as inferior ganglion cells die first)
- Sequence of field defect in glaucoma: Paracentral → Seidel → Arcuate → Ring scotoma
- Frequent change of presbyopic glasses is an early symptom of open angle glaucoma.
- DOC for POAG/ PACG is prostaglandin analogues
- DOC for Acute angle closure/ Acute congestive glaucoma is Pilocarpine
- In acute angle closure, vertically mid dilated pupil is seen
- Uveitis with raised IOP is best managed by Steroids
- Raised IOP in uveitis is managed using Timolol
- Pilocarpine is C/I in uveitis
- Mechanism of antiglaucoma drugs:
- PGF2α analogues: ↑Uveoscleral outflow
- α2 agonists: ↓Aqueous production
- Important side effects of antiglaucoma drugs:
- Latanoprost – Eyelid pigmentation
- Brimonidine – Drowsiness
- Timolol – Blepharoconjunctivitis
- Dipivefrine – Follicular conjunctivitis.
- Brimonidine has neuroprotective action but it is C/I in children as it causes CNS suppression and sleep apnea
- Epinephrine can’t be used in aphakic glaucoma because it causes Cystoid macular edema in aphakics
- Atropine is contraindicated in all types of glaucoma except in malignant glaucoma where it is DOC (Atropine helps to open the block so that aqueous starts flowing anteriorly)
- Triple procedure consists of:
- Extracapsular cataract surgery
- PCIOL implantation
- Glaucoma filtering operation.
- Express implant used in glaucoma are made of stainless steel.
- Inverse glaucoma is seen in microspherophakia (a developmental abnormality in which the lens is small in diameter and spherical, MC condition where it is seen: Weill-Marchesani syndrome)
- “100 day glaucoma” is seen in central retinal vein occlusion (CRVO)
- Barkan’s membrane is thought to cause congenital (= infantile) open angle glaucoma by blocking the openings of trabecular meshwork
- Earliest symptom in congenital glaucoma: Photophobia
- Most common symptom in congenital glaucoma: Watering
- In congenital glaucoma, Cupping of optic disc is reversible upto 2 yrs of age once IOP is normalized
- Treatment of choice in congenital glaucoma: (Trabeculotomy + Trabeculectomy) > Goniotomy
- MC complication of anterior uveitis/ iridocyclitis – Secondary open angle glaucoma
- Most common type of secondary glaucoma is pseudoexfoliative glaucoma
- Phacolytic glaucoma occurs due to leakage of high molecular weight lens proteins through the degenerated capsule of hypermature Morgagnian cataract
- Lens particle glaucoma is due to penetrating trauma which ruptures the lens capsule and lens material escapes out
- The key difference is the history of trauma and status of lens capsule (leaky but intact in phacolytic glaucoma; ruptured in lens particle glaucoma)
- Phacomorphic glaucoma is the term used for secondary angle-closure glaucoma due to lens intumescence (Causes: advanced cataract/ rapidly intumescent lens/ traumatic cataract)
- Pigmentary glaucoma:
- Pigment accumulation in the trabecular meshwork reduces aqueous outflow facility and may result in elevation of IOP
- It is common in males and myopics
- Characteristic feature: Krukenberg spindle (pigment along the corneal endothelium).
- Vogt’s triad: Evidence of previous attack of angle closure:
- Iris atrophy
- Pigment deposition in endothelium.
- Glaukomflecken is grayish-white anterior subcapsular lens opacities that occur following an episode of markedly elevated IOP.
Halos in glaucoma:
- History of colored halos is never present in steroid induced glaucoma
- Fincham test is used for differentiating halos of angle closure glaucoma & immature cataract.