eye and vision problems continued and eye drugs Flashcards
What is retinal detachment?
separation of the neurosensory layer of the retina from the outermost pigmented epithelium, which normally shields the retina from excess light and provides structural supsport for the retina. this leads to degeneration of photoreceptors and vision loss.
What are some causes of retinal detachment? What patients are more at risk?
retinal breaks, diabetic draction, inflammatory effusions
breaks are more common in pts with high myopia
Clinical picture of retinal detachment?
often preceded by posterior vitreous detachment- patient will see flashes and floaters. This leads to eventual monocular vision loss like a “curtain drawn down. this is a surgical emergency
What is age-related macular degeneration?
degeneration of the macula (center of the retina). this causes distortion (metamorphosia) and eventual loss of centrla vision
What is dry age-related macular degeneration? Speed of degeneration? Findings? Treatment?
most common type this causes deposition of yellowish extracellular material in and beneath the Bruch membrane (innermost layer of choroid) and the retinal pigment epithelium. causes a gradual decrease in vision. prevent with mutivitamin and antioxidants
What is exudative macular degeneration? Speed of degeneration? Treatment?
rapid loss of vision d/t bleeding secondary to choroidal neovascularization. Treat with anti-VEGF or laser
Describe the MLF.
Key points: if lesioned, abducting eye gets nystagmus (overstimulated to try to get the CNIII to follow). Convergence is normal.
aka intranuclear ophthalmoplegia. (the INO refers to the paralyzed eye).
May be best to draw a picture, but wordy explanation exists below
allows for cross talk btw the CN VI and CN III nuclei. very myelinated, and lesions may be seen in patients with demylination disorders like MS. If lesioned, ipsilateral CNVI nucleus (controlling gaze to ippsilateral side) works, but contralateral CN III nucleus doesn’t stimulate the medial rectus to fire.
What is the end goal of glaucoma drugs?
decrease intro-ocular pressure via decrease in aqueous humor (inhibit synthesis or secretion or increase drainage)
What are some classes of glaucoma drugs? (5)
alpha agonists, beta blockers, diuretics, chloinomimetics, prostaglandins
Epinephrine for glaucoma: mechanism, sides, contraindications
causes mydriasis. don’t use in closed angle glaucoma
this will decr. aqueous humor synthesis via vasoconstriction
Brimonidine: MOA, sides
will decreased aqueous humor synthesis.
alpha 2 agonist
may cause blurry vision, ocular hyperemia, foreign body sensation, ocular allergic reactions, and ocular pruritis
What beta blockers are used to treat glaucoma? MOA, sides?
timolol, betaxolol, carteolol
decreased humor synthesis
no pupillary or vision changes
How is acetazolamide used to treat glaucoma? MOA, class, sides
diuretic
decreases aqueous humor synthesis via inhibition of carbonic anhydrase
no pupillary or vision changes
What are direct cholinomimetics for glaucoma treatment? Side effects?
pilocarpine, carbachol.
these increase outflow of aqueous humor via contraction of the ciliary muscle and opening of trabecular meshwork.
cause miosis and cyclospasm (contraction of ciliary muscle). remember that the ciliary muscle does accomodation, not pupil size
What are indirect cholinomimetics for glaucoma treatment?
physostigmine, echothiophate. they also incr. outflow of aqueous humor via contraction of the ciliary muscle and opening of trabecular meshwork. sides are also miosis and cyclospasm
