What is normal IOP
Determinants of IOP
- 10-20mmHg
1. aqueous humor most important: obstruction to flow from closed or open angle glacoma. mydriasis can impede flow (phenylephrine, epi, BB echiophate)
2. increase in Blood volume from increase CVP or arterial BP
3. mass effect/external compression
4. Anetshestics: decrease via lowering CVP, EOM tone, and resistance to aqueous humor drainage (by causing miosis). succ may cause transient increase,
5. hypercarbia hypoxia acidosis can increase ICP (increase choroidal dilation-layer in posterior globe containing blood vessels and capillaries
Drugs used to treat glacoma
- first line-topical cholinergics (echothiolate-acteylcholinesterase inhibitor-prolong succ miva, and ester locals), BB, adrenergics
- carbonic anhydrase inhibitors
- surgery
- acute think of mannitol
Response to OCR
- tell surgeon to stop
- if severe tx w atropine/CPR 20mcg/kg
- correct any hypoxia or hypercabia that worsens reflex
- . persisted cconsider infiltration of EOM w local
- self limited and self extinguishes
Issues w suc in opthamology
- interfere w forced duction test used to access EOM imbalence
- may predispose to MH?
- may make IOP pressure testing inaccurate
implications of strabismus
- NMD MH risk- no longer considered an issue
- OCR
- succ & forced duction test
- N/V common
etiology post post op blindess
RF for AION, tx?
ION-anterior posterior (decreased oxygen delivery to optic nerve): painless, decreased pupiillary response to light, visual field defect, lack light perception, + optic disc edema in anterior (normal disc in posterior)
central retinal artery/vein occulision: CRAO: cherry red macula, imapird light reflex, branch: either normal or mpaired light reflex
acute glacoma; severe periobital pain, pale and dry eye, dilated pupil
hemorragic retinopathy: floaters, pre-retinal hemorrhages, retinal edema
cortical blindness: inabillity to follow moving objects w head stationary, absent response to visual threat,
glycine toxicity: dilated nonreactive pupil,
corneal abrasiaon: foregn body sensation, conjutiviits, photophobia, tearing
RF: atherosclosis, age, HTN smoking DM, vascular dz, increased IOP
hypotension, anemia, vasoconstrictors
timing for intravitreal injection of air sulfur hexafluoride ) or perfluoropropane (C3F8) and nitrous
air 5 days
sulfur hexaflurodide 10 days
perfluropropane 30 days
what to do when POVL occurs
-impaired oxygen delivery: correct hypotension, aanemai electrolytes
elevated head of bed to failitate venous drainage
urgent optha consult
RF for PION
how to reduce risk
prolonged procedures >6.5 hrs & susstancial blood loss 45% of EBV have strongest association -consider staging procedures
type and amount of fluid admin
prone
avoid hypoxia, hypotension anemia,
keep head above heart to promote venous drainage
avoid excessive pressure on eyes
staging procedure-if long and complications
