Glaucoma and ocular hypertension Flashcards
(26 cards)
What is glaucoma?
A group of eye disorders characterized by optic nerve damage and visual field loss, often associated with raised intra-ocular pressure (IOP).
What is the main treatable risk factor for glaucoma?
Raised intra-ocular pressure (IOP).
What is the most common type of glaucoma?
Chronic Open-Angle Glaucoma (COAG).
Slow drainage of aqueous humour through a partially blocked trabecular meshwork, despite the drainage angle being open.
What is acute angle-closure glaucoma?
A sight-threatening emergency where the iris blocks fluid outflow, causing a sudden rise in IOP.
What is ocular hypertension?
IOP > 21 mmHg without optic nerve damage or visual field loss.
What is the first-line treatment for COAG or ocular hypertension (IOP ≥ 24 mmHg)?
360° Selective Laser Trabeculoplasty (SLT).
It stimulates the trabecular meshwork to improve aqueous humour drainage.
Name first-line pharmacological treatments for glaucoma.
Topical prostaglandin analogues: latanoprost, tafluprost, travoprost, bimatoprost.
What if prostaglandin analogues are not effective or not tolerated?
Try:
Another prostaglandin analogue
Then a topical beta-blocker (e.g., timolol)
If still ineffective, use carbonic anhydrase inhibitors, sympathomimetics, or miotics
What drug class is mitomycin, and when is it used?
Antimetabolite/chemotherapy drug used off-label during glaucoma surgery to prevent scarring.
What is the mechanism of action of prostaglandin analogues in glaucoma treatment?
They increase uveoscleral outflow of aqueous humour, thereby reducing intraocular pressure (IOP).
Prostaglandin analogues, like latanoprost, work by activating a specific prostaglandin receptor (FP receptor). This activation leads to changes in the ciliary muscle and sclera, increasing the space between the muscle fiber bundles, which facilitates fluid outflow.
List four prostaglandin analogues used in glaucoma management.
Latanoprost, tafluprost, travoprost, and bimatoprost.
What are common side effects associated with prostaglandin analogues?
Conjunctival hyperaemia (a condition characterized by redness and inflammation of the conjunctiva, the clear membrane covering the white part of the eye), increased iris pigmentation, eyelash growth, and periorbital skin darkening.
How should prostaglandin analogues be administered?
One drop into the affected eye(s) once daily, preferably in the evening.
How do beta-blockers lower IOP in glaucoma patients?
By reducing aqueous humour production through blockade of beta-adrenergic receptors in the ciliary body.
Name three beta-blockers commonly prescribed for glaucoma.
Timolol, betaxolol, and levobunolol.
What systemic side effects can topical beta-blockers cause?
Bradycardia, hypotension, bronchospasm, and fatigue.
What are contraindications for the use of topical beta-blockers?
Asthma, chronic obstructive pulmonary disease (COPD), sinus bradycardia, and certain heart blocks.
Describe the mechanism of action of carbonic anhydrase inhibitors in glaucoma therapy.
They inhibit carbonic anhydrase in the ciliary processes, decreasing aqueous humour secretion and lowering IOP.
Provide examples of topical carbonic anhydrase inhibitors.
Dorzolamide and brinzolamide.
What are potential side effects of carbonic anhydrase inhibitors?
Ocular discomfort, bitter taste, and, rarely, systemic effects like fatigue and kidney stones.
How frequently are carbonic anhydrase inhibitors typically administered?
One drop into the affected eye(s) two to three times daily.
Name two sympathomimetic drugs used in glaucoma management.
Brimonidine and apraclonidine.
What are common adverse effects of sympathomimetics?
Dry mouth, fatigue, ocular redness, and allergic conjunctivitis.
How often should brimonidine be administered for glaucoma?
One drop into the affected eye(s) twice daily, approximately 12 hours apart.
