Learn more about glaucoma, which is a disease that can damage the eye's optic nerve.
Glaucoma: anatomy, diagnosis and treatment
Glaucoma is a group of eye diseases that cause progressive and permanent damage to the optic nerve. This is often related to increased pressure in the eye.
Risk factors for glaucoma:
-over age 40
-African descent
-decreased central corneal thickness (pachymetry)
-family history of glaucoma
-thinning of retinal nerve fiber layer of optic nerve
-increased IOP
Anatomy of glaucoma:
-ciliary body makes aqueous fluid
-aqueous fluid drains out of the angle and is returned to the bloodstream
-The balance of this fluid production and drainage is what causes the IOP
-if the IOP gets too high, it can damage the fibers of the optic nerve
-if this happens it can lead to permanent vision loss
Types of glaucoma:
-Primary open angle glaucoma
-angle is draining, but is not efficient, and IOP can increase
-most commonly what we will see
-slow progressive vision loss
-Angle closure glaucoma
-angle closes completely and IOP increases dramatically
-severe sudden eye pain, blurry vision, headache, vomiting
-emergency situation that needs prompt treatment
-more common in hyperopes
-Pigmentary glaucoma
- pigment is rubbed off of the iris and collects in the angle
-this can eventually cause drainage to be reduced and increase IOP
Diagnosis of glaucoma:
-case history to determine family history, previous eye injuries or surgeries
-IOP measurement every exam
-normal range is 10-21mmHg
-can still have glaucoma with “normal” IOP
-can not have glaucoma with high IOP
-biggest risk factor for developing glaucoma
-Optic nerve assessment
-increase cup to disc ratio, asymmetry between eyes, ONH bleeding
- OCT measures eye against control database of healthy eyes
-can help determine if there may be abnormal optic nerve thinning
-can be used over time to monitor progression
-visual field
-glaucoma first affects peripheral vision
-patient may not realize they have a visual field defect
-visual field defects must be repeatable
-can be used the monitor progression
-pachymetry
-measurement of central corneal thickness
-normal CCT is about 550
-reduced CCT is glaucoma risk factor
-gonioscopy/angle assessment
-needed to assess if angle is open, or if pigment is present
Glaucoma treatment:
-the goal is to reduce the IOP to a level that prevents further damage to optic nerve and further loss of vision
-medication can either reduce the amount of aqueous fluid that is made or it can increase the amount of drainage either through the angle or directly through the sclera
-laser surgical procedures can be used to increase the drainage through the angle
-small shunts can be placed within the eye to help with drainage
Take away important points:
-glaucoma is leading cause of irreversible blindness worldwide
-someone can develop glaucoma over time so if they are fine one year it does not mean they are fine forever
-increased IOP is biggest risk factor for glaucoma, but can still have glaucoma with “normal” IOP
-important to diagnose as early as possible to reduce vision loss
-important to monitor over time to track progression and treatment success
-open angle glaucoma really does not have symptoms, so it is important to have exam to monitor risk over time
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