Common Causes For Loss Of Sight

The Most Common Causes For Loss Of Sight In People Over The Age of 40 Are:

• Glaucoma
  
• Cataracts
  
• Diabetic Eye Disease
  
• Macular Degeneration

---

Early detection is the best way to preserve your sight

Glaucoma – is a very specific type of degeneration of the eye’s never fibers resulting in a decline in peripheral and night vision and progresses to a tunnel of vision before blindness.  Glaucoma may or may not be associated with high eye pressure.

50% of the people in North America who have glaucoma are yet to be diagnosed with their disease.   Early detection, diagnosis and management can stop or slow down the rate of progression of nerve death and thereby save sight.

There are two major types of glaucoma:

1. Angle Closure Glaucoma – a sudden rise in eye pressure with pain and foggy vision.    High pressure can result in damage to the optic nerve if it is left untreated.

2. Open Angle Glaucoma – is more common and produces a painless, slow progressive loss of (peripheral) vision,

Risk Factors For Glaucoma

• Family history of glaucoma
• Females of Asian descent
  
• Persons of Hispanic descent
  
• Persons of African descent (6x at risk)
  
• Very nearsighted eyes
  
• High intra-ocular pressure
  
• Very Thin Corneas
  
• Untreated high blood pressure
  
• Smoking
  
• Advancing age >40 years old
  
• History of migraine headache
  
• History of eye trauma

Cataracts – although you can be born with cataracts, most people are born with a clear lens inside their eye.  The lens loses its transparency with age and vision is eventually compromised.   When your best corrected vision drops below 20/40 most people will have surgery to replace their clouded lens with an artificial clear lens.

There are 196 different types of cataracts.  Cataract surgery is painless, takes about 15 minutes and is the most common eye surgery in the world.

Risk Factors For Cataracts

• Family history of cataracts
• Age
• Diabetes
• Exposure to UV and/or infrared light
• Poor diet
• Many Medications

Diabetic Eye Disease – Diabetics are 25 times more likely to become legally blind than non-diabetics yet only 4 out of every 10 diabetics seek an annual eye examination.   Half of the diabetics in the developed world do not even know they have the disease.

Advancing diabetes results in a breakdown of the blood vessels inside of your eyes.  Besides the effects of high blood pressure, diabetics are at risk for bleeding, fluid leakage, tissue swelling, scaring and detachment of the retina.

Many people with diabetes are first diagnosed when their optometrist sees its affect during a routine eye examination.  Once diagnosed, everyone with diabetes must have annual eye examination.

Macular Degeneration – All of the light entering and eye comes to focus on a small point about the size of a pinhead called the macula. The healthy macula gives clear crisp vision and colour perception.  The rest of the retina is used for peripheral vision and motion detection.  Any change in the architecture of the macula and its 4½ million cone cells will result in a dramatic and often permanent loss of central vision.

People with macular degeneration lose their central vision and therefore their ability to read, drive a car, see a golf ball and recognize the face of a friend or family member.

Some medications and other diseases can also compromise or destroy the macula.  It is important to differentiate a macular disease from macular degeneration.  Early changes to the macula are so microscopic that the human eye cannot detect change until damage is already done.  Early examination with advanced technologies is the only way to detect subtle changes to the macula before damage is done.

Your Best Defense Is A Good Offence.

1. have an annual eye examination

2. follow the advice given to you by your optometrist

3. maintain a healthy lifestyle

4. take full advantage of new technologies which can detect glaucoma six years earlier than previous technologies and detect macular degeneration before there is loss of sight.

Early Detection With New Technologies

• Ocular Coherence Tomography is like an ultrasound but with light.   OCT will see each of the 10 sub-layers of the retina and detail this structure in 10 micron sections.  OCT is the only way to see the macula in all of its detail and detect microscopic fluid accumulation or separation of layers at the macula before sight is lost.  The OCT will also measure the diameter, depth and volume of the optic nerve where it joins the eye.  This measurement is necessary to assess the progression of glaucoma.  The OCT test is painless and takes about 5 minutes.  Our clinic was the first optometry clinic in Vancouver to have this technology.

• GDx VCC – will measure the thickness of the 1.5 million retinal never fibers as they enter the optic nerve.  The GDx VCC will aid in detecting glaucoma damage six years before a loss of your visual field.  The test is painless and takes 0.8 seconds. Our clinic was the first optometry clinic in BC to have this technology.

• Visual Field Testing – assesses how much light it takes to travel from the eye, through the optic nerve to the brain.  The instrument documents glaucoma damage after 50% of the never fibers (measured with the GDx or OCT) are lost to glaucoma.  This instrument can also be used to detect brain tumors, damage from a stroke and other diseases that affect the nerves communicating from the eye to the brain.  MSP may pay for this service within certain guidelines.

• Pachymetry – is an ultrasound device used to measure the thickness of the front surface of an eye (the cornea).  It has only been since 2002 that eye pressure was found to be related to corneal thickness. Thin corneas are at a higher risk for glaucoma. Anyone at risk for glaucoma and anyone with a history of laser eye surgery (PRK or LASIK) should have this test to help determine the true pressure of their eye.

• Retinal Photography – using a camera to document the status of the internal structures and health of the eye.  Our notes are good, but there is no substitute for a photograph in documenting the details inside of an eye.  Anyone with high blood pressure, diabetes, HIV or any retinal disease should have photo- documentation to detect subtle change over time. 

• Corneal Topography – is a way to measure the contours on the surface of an eye.  Anyone with high astigmatism, corneal degeneration, keratoconus or laser eye surgery (PRK or LASIK) would benefit from this assessment. Our clinic was the first optometry clinic in BC to have this technology.