Glaucoma The Canadian Association of Optometrists

GlaucomaGlaucoma

The Canadian Association of Optometrists

www.opto.ca The Canadian Association of Optometrists

What is Glaucoma?

• Glaucoma is an eye disease where the eye’s optic nerve is damaged

• It is one of the leading causes of blindness in Canada


Eye Anatomy

• The optic nerve is a bundle of nerve fibers

• It carries visual information from the retina to the brain


Fluid Circulation

• The eye has an internal fluid circulation system

• Fluid is produced at the base of the iris


Fluid Circulation

• The fluid flows through the pupil to the front of the iris


Fluid Circulation

• The fluid exits the eye at the angle between the iris and the cornea where it drains through a spongy meshwork


Forms of Glaucoma

• There are several different forms of glaucoma– Primary Open Angle Glaucoma

– Low Tension Glaucoma

– Secondary Glaucoma

– Angle Closure Glaucoma


Primary Open AngleGlaucoma (POAG)

• POAG is the most common form of glaucoma• It occurs when the fluid drainage is poor and fluid

builds up in the eye and the internal eye pressure goes up

• This increased pressure can cause damage to the optic nerve and vision loss

• The exact mechanism of damage is still unknown


Symptoms of Primary OpenAngle Glaucoma

• POAG develops gradually and painlessly and has no initial symptoms

Vision is normal in the early stages



• If untreated, peripheral or side vision is slowly lost

Tunnel vision



• Eventually, all vision may be lost


Risk Factors for PrimaryOpen Angle Glaucoma

• High Intraocular (Eye) Pressure• Over the age of 40• Family history of glaucoma• African or Caribbean descent• Thin cornea• High myopia (Nearsightedness)• Diabetes• High blood pressure


Ocular Hypertension

• Some people can have high eye pressure but the optic nerve does not get damaged

• This condition is called ocular hypertension• These patients must be closely followed because

of the risk of developing glaucoma


Low Tension Glaucoma

• Low Tension (or Normal Tension) Glaucoma is not as common

• In these cases, the eye pressure is in the normal range but the optic nerve still gets damaged

• The exact mechanism of damage is still unknown


Secondary Glaucoma

• Glaucoma can develop as a complication from other conditions including:– Eye injuries

– Uveitis (internal eye inflammation)

– Pigment dispersion

– Diabetes (Neovascular glaucoma)

– Steroid use


Angle Closure Glaucoma

• This type of glaucoma is an emergency situation• It occurs when the iris itself blocks the drainage

angle and results in a sudden increase in pressure• Symptoms include severe eye pain, nausea, eye

redness and very blurred vision• Immediate treatment is required


How is glaucoma detected?

• Regular eye examinations by an optometrist or ophthalmologist are vital to detecting glaucoma

• A number of tests are performed


Glaucoma Tests:Case History

• A patient’s medical history, family history and background are important to determine the presence of risk factors


Glaucoma Tests:Visual Acuity

• A refraction is done to determine best corrected vision• This shows central vision function


Glaucoma Tests:Slit Lamp & Gonioscopy

• A special microscope called a slit lamp is used to examine the structures of the eye

• A gonioscopy lens may be used to view the drainage angle


Glaucoma Tests:Tonometry

• Eye pressure is measured with an instrument called a tonometer

• Three types that are commonly used are:– Goldmann (Perkins)

– Non-contact (air puff)

– Tonopen


Glaucoma Tests:Ophthalmoscopy

• Eye drops may be placed in the eyes to dilate the pupils• Special magnifying lenses are used to examine the retina

and optic nerve for damage

Normal Optic Nerve Suspicious Optic Nerve


Glaucoma Tests:Ophthalmoscopy

• Advances are being made in digital imaging of the retina


Glaucoma Tests:Visual Field Test

• Peripheral (side) vision is tested with a perimeter

The patient responds to flashes of light in different locations


Recent Developments

• Recent studies have found that patients with thin corneas have a greater risk of developing glaucoma

• Measurement of corneal thickness using an instrument called a pachymeter will become increasingly important


Recent Developments

• New tools for measuring peripheral vision (visual field) have been developed such as the FDT


Recent Developments

• Laser technology can now be used to image the retina and optic nerve and measure nerve fiber layer thickness


Recent Developments


Glaucoma Management

• Optometrists and Ophthalmologists work closely together to treat glaucoma

• Optometrists refer patients who are diagnosed with glaucoma to Ophthalmologists to start treatment


Glaucoma Management

• Once treatment is started, monitoring duties are often shared. This includes regular pressure measurements and visual fields.

• Ophthalmologists perform any surgical treatments if necessary


Glaucoma Treatment

• The goal is to decrease the eye pressure• The three main categories of treatment are:

– Medication

– Laser trabeculoplasty

– Conventional surgery

• Unfortunately, these treatments will not reverse any existing damage but they can slow the progression of the disease


Glaucoma Medications

• Medications are usually the first type of treatment used

• Eyedrops or pills are used to either decrease the fluid production or to increase the fluid drainage


Glaucoma Medications

• There are several different types of medication available

• The right choice will depend on what other medications are being taken, other medical conditions and the effectiveness in decreasing the eye pressure

• Often, combinations of eyedrops are used


Laser Trabeculoplasty

• This laser treatment helps to increase the fluid drainage

• The surgeon uses a laser to burn the spongy meshwork that is located in the drainage angle


Conventional Surgery

• With this treatment, the surgeon creates a new opening in the eye for the fluid to drain out from

• If the new opening becomes plugged or narrowed, further surgery may be required


Coping with Vision Loss

• Many patients with sight loss due to glaucoma can benefit from low vision aids

• Optometrists can perform low vision assessments and prescribe magnifying devices to enhance both distance and reading vision


Coping with Vision Loss

• These aids will not restore sight to normal levels but they allow people to maximize the amount of vision remaining


Early Detection and Treatment

• Regular eye health examinations are important to detect glaucoma early so that treatment can be started and vision loss can be prevented

YYOUROUR E EYESYES deserve deserve ANAN OOPTOMETRISTPTOMETRIST!

The Canadian Association of Optometrists

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Glaucoma The Canadian Association of Optometrists