Drugs for the Eye

Question 1

• Group of diseases characterized by a decrease in peripheral vision secondary to optic nerve damage
• Primary open-angle, acute angle-closure
• Leading cause of blindness in the United States

Answer 1

Glaucoma

Question 2

• Progressive optic nerve damage with eventual impairment of vision
• IOP often elevated

Answer 2

Primary Open-Angle Glaucoma

Question 3

Precipitated by displacement of the iris such that it covers the trabecular meshwork, preventing the exit of aqueous humor from the anterior chamber

Answer 3

Angle-closure glaucoma

Question 4

Betaxolol, carteolol, levobunolol, metipranolol, and timolol

• Lower IOP by decreasing production of aqueous humor
• Used primarily for open-angle glaucoma
• Adverse effects: Conjunctivitis, dry eye, blurred vision, photophobia; can also produce bradycardia and atrioventricular (AV) heart block

Answer 4

Beta blockers

Question 5

Latanoprost, travoprost, bimatoprost, latanoprostene bunod, tafluprost

• Lowers IOP by facilitating aqueous humor outflow, in part by relaxing the ciliary muscle
• Side effects: harmless heightened brown pigmentation of the iris; may also increase pigmentation of the eyelid and may increase the length, thickness, and pigmentation of the eyelashes
• Other side effects include blurred vision, burning, stinging, conjunctival hyperemia, conjunctival edema, and punctate keratopathy
• Travoprost: more effective in blacks than nonblacks

Answer 5

Prostaglandin analogs

Question 6

Apraclonidine (short-term), brimonidine (short-term and long-term)

• Lowers IOP by reducing the production of aqueous humor and perhaps by increasing outflow
• Brimonidine: may delay optic nerve degeneration and protect retinal neurons from death; can cross BBB
• (1) short-term therapy of open-angle glaucoma in patients who have not responded adequately to maximal doses of other IOP-lowering drugs and (2) preoperative medication before laser trabeculoplasty or iridotomy; does not cross BBB
• Adverse effects: dry mouth, ocular hyperemia, local burning and stinging, headache, blurred vision, foreign body sensation, and itching

Answer 6

Alpha-2 Adrenergic Agonists

Question 7

• Direct-acting muscarinic agonist
• (1) miosis (constriction of the pupil secondary to contraction of the iris sphincter) and (2) contraction of the ciliary muscle (an action that focuses the lens for near vision)
• IOP is reduced because the tension generated by contracting the ciliary muscle promotes widening of the spaces within the trabecular meshwork, thereby facilitating outflow of aqueous humor
• In angle-closure glaucoma, contraction of the iris sphincter pulls the iris away from the pores of the trabecular meshwork, thereby removing the impediment to aqueous humor outflow
• Adverse effect: Occasionally sustained contraction of the ciliary muscle causes retinal detachment. Constriction of the pupil, caused by contraction of the iris sphincter, may decrease visual acuity

Answer 7

Pilocarpine

Question 8

• Cholinesterase inhibitors inhibit breakdown of acetylcholine by cholinesterase and thereby promote accumulation of acetylcholine at muscarinic receptors
• As a result, they can produce the same ocular effects as pilocarpine (i.e., miosis, focusing of the lens for near vision, and reduction of IOP)

Answer 8

Echothiophate

Question 9

• Lowers IOP by decreasing production of aqueous humor
• Carbonic anhydrase inhibitors tend to be less effective than other drug therapy for glaucoma
• The most common side effects are ocular stinging and bitter taste immediately after dosing
• Between 10% and 15% of patients experience allergic reactions, primarily conjunctivitis and lid reactions

Answer 9

Dorzolamide/Brinzolamide

Question 10

• Acetazolamide and methazolamide
• Employed primarily for long-term treatment of open-angle glaucoma
• Effects on the central nervous system (CNS), which are relatively common, include malaise, anorexia, fatigue, and paresthesias
• Teratogenic

Answer 10

Oral carbonic anhydrase inhibitors

Question 11

• Contain polyvinyl alcohol, cellulose esters
• Isotonic solutions employed as substitutes for natural tears

Answer 11

Ophthalmic demulcents

Question 12

• Weak solutions of adrenergic agonists applied topically to constrict dilated conjunctival blood vessels
• Phenylephrine, naphazoline, oxymetazoline, brimonidine, and tetrahydrozoline

Answer 12

Ocular decongestants

Question 13

• Water-soluble dye that produces an intense green color
• Applied to the surface of the eye to detect lesions of the corneal epithelium; intact areas of the cornea remain uncolored, whereas abrasions and other defects turn bright green

Answer 13

Fluorescein