Glaucoma is an eye disease where there is an increased intraocular pressure that effects the optic nerve of the eye. Over time, this pressure can cause permanent damage to the eye – largely affecting vision.
The pressure increases because of increased fluid (aqueous humor) pressure as it flows through the trabecular meshwork.
The increase of pressure is seen in the anterior chamber. Pressure is typically above 21mmHG or 2.8kPa.
Some individuals can have elevated pressure in eyes for years without any damage and others can develop damage at a low pressure.
Worldwide – it is the second most common cause of blindness.
#1 cause of blindness is Cataracts
Affects 1/200 under age 50 and Affects 1/10 over age 50
Check out the Eye Anatomy – here
Two Main Categories
1.) Open-Angle
2.) Closed-Angle
***the angle is meant as the area between the Iris and Cornea.
This area is where the fluid must flow via the trabecular meshwork.
Open Angle
– Slower progression than Closed Angle
– Often patients don’t know something is wrong until its too late.
– Slow change (decrease) to vision
– Accounts for more than 90% of cases (in America)
– Accounts for 50% of cases Worldwide
Closed Angle
– Can appear suddenly
– Can be very painful
– Visual loss can progress quickly
– Discomfort causes patients to seek additional medical evaluation
– Accounts for less than 10% of cases (in America)
– Accounts for 50% of cases Worldwide
Symptoms
– Often painless – Open Angle
– Sometimes very painful – Closed Angle
– Vision loss
– Pupillary changes
– Nausea
– Vomiting
– Halo around lights – Occasional
Causes
1.) Elevated ocular pressure (Ocular Hypertension)
2.) Genetics
3.) Dietary (Potential Cause) – Caffeine increases ocular pressure
4.) Ethnicity (African decent are 3 times more likely to develop Open Angle
5.) Gender (Women x 3 times more likely to developed)
6.) Steroid Use
7.) Severe Diabetic Retinopathy
8.) Central Vein Occlusion
9.) Ocular trauma
10.) Others
Diagnosis
– Standard Eye Exam
– Tonometry – Examine Eye pressure
– Eye Acuity test
– Optic nerve examination
Treatment
*** No real improvement of vision after diagnosis – only prevention of worsening vision
– Yearly eye exams
Medications
1.) Prostaglandin Analogs
. Latanoprost (Xalatan)
. Bimatoprost (Lumigan
. Travoprost (Travatan)
*** Increases Uveosclearal outflow and Trabecular outflow (Bimatoprost)
2.) Beta-Adrenergic Receptor Antagonsists (Topical Agents)
. Timolol
. Levobunolol (Betagan)
. Betaxolol
*** Decreases Aqueous Humor by Cilary body
3.) Alpha2-adrenergic Agonists
. Brimonidine (Alphagan)
. Apraclonidine
*** Decreases Aqueous Humor
4.) Miotic Agents
. Pilocarpine – Contracts Ciliary Muscle
. Echothiophate
5.) Carbonic Anhydrase Inhibitors
. Dorzolamide (Trusopt)
. Brinzolamide (Azopt)
. Acetazolamide (Diamox)
Surgery
1.) Laser surgery
2.) Conventional surgery
*** – Typically a temporary solution
*** – Surgery is not a cure
Others
Glaucoma Drainage Implants
Scleretomay via Laser Therapy
Veterinary Implant
Marijuana
– Marijuana treatment has been evaluated in studies since the 1970s.
– Can be smoked or eaten
– Reduces pressure by 25%
– Topical application has not been beneficial.