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Glaucoma

February 28, 2022

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