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What is glaucoma? what causes it?
- High intraocular pressure.
- caused by an imbalance between aqueous humor production (cilliary bodies) and egress (at the irido-corneal angle into the canal of schlemm)
2 types of glaucoma?
- Open angle.
- Closed angle. (Acute glaucoma)
What is normal eye pressure?
What is the mechanism of open angle glaucoma?
Degeneration / clogging of the trabecular meshwork results in aqueous build up and chronically elevated eye pressure.
High pressures lead to comprimise of vascualr supply to optic nerve and cause gradual loss of vision.
What are the classic optic disc changes in open angle glaucoma?
- Optic atrophy
- Increased cupping
- Loss of the ISNT Rule of the neural rim (inferior, superior, nasal, temporal. Thickest to thinnest)
- Disc haemorrhage
- Displacement of vessels nasally.
Risk factors for open angle glaucoma?
- Family history
- Afro carribeans
- Thin corneas
- High eye pressure
Characteristic visual loss in glaucoma?
Central sparing and peripheral blindness.
Aim of Rx for open angle glaucoma? What are your options?
- Prostaglandin analogues - increase outflow
- B-Blockers - decrease production
- Carbonic anhydrase inhibs - Acetazolomide
- Laser procedure to burn ciliary body or create holes in meshwork.
How does acute angle closure glaucoma present?
- Extremely red, painful eye
- Halos around lights
- Sluggish and dilated pupil
- Ocular pressure >60mmHg
Rx for acute angle closure glaucoma?
- Decrease pressure QUICKLY
- Topical B Blocker - timolol - decrease production
- Acetazolomide - decrease production
- Miotic - Pilocarpine - constrict pupil and open angle
- Surgically - laser treatment.
Causes of sudden PAINLESS loss of vision?
- helps to think of the passage of the photon - retina - AP - occipital lobe.
- Vitreous haemorhage
- Retinal detachment
- Wet AMD
- Retinal artery\vein occlusion
- Optic neuritis
Retinal Detachment - presentation?
- Sudden onset loss of vision preceeded by flashing lights and floaters.
- Macula involved - central visual loss
- Macula not involved - peripheral visual loss
What is Dry amd? pathology, presentation and Rx?
- Pathology - accumulation of drusen in the layer betwen the choroid and the RPE.
- Present with central visual loss
- Treat with antioxidants (little evidence)
What is Wet amd? pathology, presentation and Rx?
- Pathology - abnormal proliferation of bloodvessels from the choroid into the RPE
- Presentation - Central visual loss - fast progression.
- Rx - Lucentis, Avantis, macugen or other anti VEGF Mabs.
- Laser photocoagulation.
Before what age can a squint be corrected?
What is the name of the test with intersecting lines on a piece of paper with a black dot in the middle used to diagnose AMD?
- Amsler grid.
- AMD patients see distorted, bent or missing lines surrounding the dot.
What tests can you do to elicit a squint?
- Corneal refelection with a pen torch.
- Cover, uncover test.
- Assess occular movement to see if you can force a squint and show that there is a plegic\paralysed ocular muscle.
What is Amblyopia and how do you treat it?
Literally - the eye is going for a walk...assoc with squints and refers to suppresion of visual information from the affected eye.
Treat by covering the unaffected eye with a patch for a minimum of 6 hours per day.
Causes of a red eye? in order of commonality
- Conjuctivitis - Infective, dry or allergic
- Episcleritis - sectorial redness
- Iritis - mild pain and photophobia, small pupil, redness only around cornea
- Corneal keratitis - sharp pain
- Scleritis - can be severe pain
- Acute Glaucoma - Lots of pain, large fixed pupil
What features of a red eye would make you think infective conjunctivitis over other diagnoses?
- Sticky, irritation but NOT pain.
- Blurry vision cleared by blinking
the grades of hypertensive retionpathy and