Glaucoma Flashcards
What secretes aqueous secretion?
non-pigmented ciliary epithelium
What forms the major proportion of resistance to aqueous outflow?
-> juxtacanalicular meshwork (outer part of trabecular meshwork)
Describe the aqueous outflow
- trabecular -> 90% through trabeculum into Schlemm canal and then drained by episclera veins
- Uveoscleral route -> 10% aqueous passes across the face off the ciliary body into suprachoroidal space
N.R. of IOP
11-21 mmHg
-> normal IOP varies within 5mmHg daily with time/ heartbeat, BP, Respiration
Define Glaucoma
needs 3:
1. intraocular pressure (high, normal, or low)
2. optic neuropathy
3. visual field loss
RF of Glaucoma?
- high IOP
- Corticosteroids
- Central retinal vein occlusion
- FH
- Uveitis
- Myopia
- DM
- Insufficient blood circulation
- CT abnormalities
How to diagnose glaucoma?
- Tonometry
- Pachymetry (thickness of cornea)
- Gonioscopy
- Fundus examination
- Visual field test
- Optical coherence Tomography
- Scanning Laser Poplarimetry
- Scanning Laser Ophthalmoscopy
What is the G.S. for diagnosis of Glaucoma?
Goldmann Tonometry
What is the most anterior structure of angle structures?
Schwalbe line
Define evaluation of optic nerve head in regards to Glaucoma
Neuoretinal rim: tissue btw. outer edge of cup and disc margin
-> normal: c/d ratio of 0.3 or less (cup/ disc)
-> asymmetry of 0.2 or more -> susp. of Glaucoma until proven otherwise
Symptoms + RF of open- angle Glaucoma
RF:
-Age (>65 more common)
-Race (blacks)
-FH (if FH screen from age of 40)
-Dm
-reduction of rerfusion pressure
-myopia
-retinal disease (CRVO, rhegmatogenous RD, RP)
Symptoms:
-Initially often asymptomatic
-mild headaches, impaired adaptation to darkness
-Generally bilateral, progressive visual field loss (from peripheral to central)
First sign of visual defect in glaucoma
paracentral (commonly supero-nasally)
Define grading of glaucomoatous dmagae
1-4
1: mild
4: end-stage
Define CF of acute-angle closure glaucoma + RF
-Sudden onset of symptoms
-Unilaterally inflamed, reddened, and severely painful eye (hard on palpation)
-Frontal headaches, vomiting, nausea
-Blurred vision and halos seen around light
-Mid-dilated, irregular, unresponsive pupil
-Complications: rapid permanent vision loss due to ischemia and atrophy of the optic nerve
RF:
-age, fh, female, race (chinese, south-east asians, eskimos)
What is Normal tension Glaucoma (NTG)?+ RF
it is:
-mean IOP< 21mmHg
-VF floss
-Open drainage angle
RF:
age
japan
female
fh
what are systemic association with NTG
raynaud (peripheral vascular spasm on cooling)
migraine
nocturnal systemic hypotension
What should you know about Pseudoexfoliation?
-> matrix material
-common in scandinavia
-in femal more present but males at higher risk of glaucoma
-present with chronic open angle glaucoma
-medical tratment
-laser trabeculoplasty
What are the two types of traumatic glaucoma?
-red blood cell glaucoma: blood clot obstructs trabecular meshowrk, hyphema (>1/2): tx: medical, ant. chamber washout
-angle recession glaucoma: previous blunt trauma, rupture of the face of the ciliary body; tx: medical, trabeculectomy (antimetabolite)
What can be the cause of congential glaucoma+ classification
trabeculodysgenesis
class:
- congenital glaucoma (intrauterine high IOP)
- infantile glaucoma (until 3 years of age)
- Juvenile glaucoma (3-16 years)
-> bilateral
Presentation of cong. glaucoma
corneal haze, epiphora, photophobia, blepharospasm
findings: buphthalmus, Haab’s stria (ruptured descement membrane)
DDx of cong. glaucoma
Birth trauma
intrauterine rubella infect.
metabolic disease
cong. hereditary endothelial dystrophy
megalocornea
nasolacrimal canal obstruction
sec. infantile glaucoma (retinoblastoma, retinopathy of prematurity, intraocular inflammation, ectopia lenitis, etc.)
Tx of Glaucoma
-Medical (topical, systemic)
-laser (laser trabeculoplasty, argon laser trabeculoplasty, selective laser trabeculoplasty, etc.)
Surgery
Describe medical tx of glaucoma
Topical:
-beta blockers (timolol, betaxolol) ->deac. aqueous secretion
-alpha2.adrenergic agonists (brimonidine, aproclonidine, etc.) -> deac. aqueous secretion & incr. uveoscleral outflow
- parasympathomimetics (pilocarpine) -> incr. trabecular outflow (in open angle) + withdrawl of iris from trabeculum (in closed-angle)
- carbonic anhydrase inhibitors (dorzolamide, brinzolamide, acetazolamide) -> decr. aqueous secretion
systemic:
for closed angle
-carbonic anhydrase inhibitors -> decr. aqueous secretion
- osmotic agents
