LEADING CAUSE OF BLINDNESS

What is the leading cause of blindness in Canada?

The leading cause of blindness in Canada is called Senile Macular Degeneration (SMD) or Age-Related Macular Degeneration (AMD.)  This pathology is associated with the retina.

SMD is the root cause of 33% of all cases that result in blindness.

What happens to the eye?

SMD is a degenerative eye disease which results in the deterioration of the macula (central part of the retina) causing the patient to have loss of sharp central vision.

Normal Vision and Vision with AMD

How bad can it get?

The vision directly in front of you (central vision) is gone.  The loss of vision is permanent and irreversible.

What does a patient experience?

        Damage to the macula results in a patient having reduced colour perception and contrast.  A patient

        may start to have difficulty reading,  driving  and recognizing  faces.  Peripheral vision remains intact, however, central vision becomes impaired.

How long does this take?

The short answer is that it can happen very quickly or take its time.  If it progresses slowly, it can take many years to reach a critical point.  And if it happens very quickly, a patient may experience vision loss from as little as a few weeks to a few months.

Who does this affect?

Generally this condition affects people 55 years of age and older.  This disease affects both eyes (bilateral) and progressively gets worse.  Given the demographics of an ageing population in Canada, the number of people who will get this disease is expected to double in the next 25 years.

Who is at risk for getting AMD?

        There are 4  factors that predisposes a patient for getting AMD

1.       Age:   greatest risk factor as the older a patient gets, chance of getting AMD increases

                                Greatly.

2.       Family History:  If there is a history of AMD in your family, your chance of acquiring the disease is increased if your parent or sibling has had it.

3.       Gender:  Studies have shown women are at a higher risk of getting AMD.

4.       Race:  Studies have shown that AMD occurs in Caucasians more frequently than

Any other race

What factors can you control from getting AMD?

There are always things that are in your control that can help prevent this disease.  The following 5 factors can help save you from this disease:

1.       Smoking:  Smokers have a greater likelihood of getting AMD—up to four times the risk

As non-smokers.

2.       Diet:  Studies have shown that your diet can help you reduce the chance of developing this disease.  A diet rich in dark, green leafy vegetables and berries can lower the risk.  These foods contain Carotenoids such as Lutein and Zeaxanthin which are healthy for you and prevent AMD from occurring.

3.       Sunlight Exposure:  Excessive exposure to the sun may cause damage of the macula

This is caused by exposure to the blue wavelengths in sunlight.  Prevention includes remaining in the shade, wearing a sunhat and sunglasses

4.       ‘Junk’ Food:  Consumption of  fat found in junk food that  include linoleic acid, monounsaturated oils  can double the risk of getting AMD.

5.       High Blood Pressure:  Hypertension has been found to be a contributing factor of AMD.

Importance of the Retina

Retina Viewed Through Ophthalmoscope



The Eye with Enlargement of Retina

The retina serves a very important role in the eye as it acts like a computer brain. It converts images from the eye into electrical impulses.  These impulses travel along the optic nerve all the way to the brain where they are interpreted as vision. 

In order to view the retina, a specialized instrument called the ophthalmoscope needs to be used.  Often an optometrist or ophthalmologist uses this instrument to observe the back of a patient’s eye.

 

The retina is nerve tissue in the eye which is light sensitive.  The retina is located in the back two-thirds of the globe and forms a thin lining approximately 0.5mm thick.

The External Retina is made up of two cell layers. 

1.       The first is the Pigmented Epithelium.  These are hexagon shaped cells packed with pigment granules located outside the retina which provide nourishment to the retinal visual cells. They are attached to the Choroid.

2.       The second is the Receptor or Bacillary Layer—This layer is made up of Rods and Cones

A normal retina has 150 million Rods and 6 million Cones

Rods are key in determining our night vision.  They are specialized retinal receptor cells that function in low light.

The Inner Retina consists of three layers.

1.       The Bipolar or Relay cells help to organize impulses from the receptors.  This layer also helps to connect the outer and inner layers of the retina.

2.       Ganglion Cell Layer contains the nuclei of ganglion cells and lies innermost to the retina.

3.       Optic Nerve Fibre Layer continues to process impulses from the receptor fibres which become bundled into the optic nerve.

 There are diseases that can affect the retina which may result in blindness.  I will discuss those on the next post.

 

 

 

 

Ageing Population

AGEING POPULATION

Demographics currently indicate that the percentage of seniors in the Canadian population is rapidly increasing.  According to Statistics Canada, by the year 2015, seniors (65+) will outnumber children (15 years and under).  By 2031, there will be 9 million seniors and only 5 million children in Canada; seniors will represent approximately 25% of Canada’s total population.[i]

 Currently, the “Baby Boomers,” who are in their early sixties and are expected to live longer than previous generations, are beginning to experience deteriorating vision.  This is the result of an association between ageing and certain eye diseases and conditions, which can cause visual impairment and blindness.  The most common of these are: age-related macular degeneration (AMD); cataracts; glaucoma; and diabetic retinopathy. Low birth rates, coupled with the increased longevity in Canada’s population, are giving rise to fears about health care provision for an ageing, visually impaired population.  Even now, the direct and indirect economic cost of vision loss in Canada is estimated at just below eight billion  dollars annually.[ii] If this situation is not managed strategically, the looming crisis may evolve beyond our control. 

 Clearly, Canada’s ageing population should be an area of concern for the ophthalmic industry.  Demography will impact the eye care industry and should be a focus of current discussions, in which we must ask the following questions: Can we manage the number of seniors coming to eye care professionals for their visual requirements?  Will we be able to address their changing visual requirements?  Do we have the workforce (human resource) capacity to service what is now a market niche, but will soon become the dominant market?

 Review of Age-related Diseases/Conditions:

 Vision is central to being independent and remaining safe.  Seniors who experience visual loss also lose a certain amount of their independence, which dramatically alters the quality of their lives.  The following diseases/conditions affect hundreds of thousands of Canadian seniors each year. 

1.  At approximately age 40, changes occur within the visual system that result in decreased visual acuity. The normal ageing process brings about a decrease in one’s ability to see sharply and to focus.  This state, referred to as presbyopia, is correctable with reading glasses or bifocals.[iii]
2.  Age Related Macular Degeneration is the leading cause of blindness in the Western world      and is prevalent in people aged 65+. 
3.  Cataracts are the leading cause of blindness in the world, according to the World Health Organization.
4. Glaucoma can also cause age-related vision loss, as pressure builds in the eye and the nerve fibers within the retina are destroyed. 
5.  Diabetic retinopathy is a condition that is secondary to diabetes.

 

 I will cover these diseases/conditions in more detail in later blog.

Current Status- Age-related Diseases and Ageing:

Researchers in Canadian universities and hospitals have made great strides in developing treatments for some of these conditions/diseases.  Improvements in drug and laser therapy have increased our understanding of how to slow the progression of certain eye diseases.  Research is presently being conducted on gene replacement therapy, optical implants, and stem cell transplants, all of which were not a possibility just ten years ago.

Notwithstanding the progress being made in the field, we must still be concerned by the fact that as the Canadian population ages, the ophthalmic industry may need to undergo tremendous adjustments.  The rapidly ageing baby boomers will be faced with physiological and functional changes in their vision, and will subsequently turn to eye care professionals.  However, despite the predicted increase in vision loss in Canada, we will experience a shortage of eye care professionals.  Meeting the needs of seniors will become difficult as wait lists to see ophthalmologists grow.  Additionally, the high demand for operating rooms for eye surgeries will only increase, considering the looming demographic crisis.

 

Noreen Khan 

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[i] Statistics Canada. The Daily: Population Projections. Available at: http://www.statcan.ca/Daily/English/051215/d051215b.htm.

Accessed September 17, 2007.

[ii] AMD Canada. News and Media- A Crisis of Vision.  Available at: http://www.amdcanada.com/template.

Accessed September 17, 2007.

[iii] Every Eye. Old Age Vision: Age Related Vision Impairment Explained.  Available at: http://www.everyeye.co.uk/htms/oldAgeVision.htm.  Accessed September 6, 2007.

 

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COSMETIC PROCEDURE FOR THE EYES--BLEPHAROPLASTY



UPPER EYELID BLEPHAROPLASTY



It is often said that by looking into a person’s eyes, can see the “windows to their soul.”   When speaking to others, it is the first place we look.  The expression on a person’s face is, to a large extent, determined by the appearance of the eyes.  The eyes, no doubt, show our emotion and convey how we feel.   It is an inevitable fact that as we age, the skin surrounding our eyes will lose elasticity, start to wrinkle and gravity will take its toll.   According to Dr. James Oestreicher, an Oculoplastic Surgeon, “the age demographics of the patients opting for eyelid surgery ranges from late 40’s to early 50’s, however, there are younger patients opting for the procedure.”  eyes or the eyes may begin to droop.   The natural effects of aging may cause the skin around the eye to sag, eventually creating a pocket or bulge. 

 

Dr. James H. Oestreicher is trained to perform cosmetic eyelid surgery.  He is a member of the exclusive American Society of Ophthalmic Plastic and We may develop ‘crow’s feet’ which are wrinkles that extend beyond the

Reconstructive Surgery (ASOPRS) for which there are only 400 members worldwide.  He performs close to 1000 procedures a year making eyelid surgery, or Blepharoplasty more popular today than before.  The popularity for the procedure may stem from the fact that we may not look as young as we feel when we look at our reflection in the mirror.  Fat bags around the eyes can make a person look tired and subsequently make them want to change their appearance.

 

This procedure involves the removal of excess skin, muscle and fatty tissue from the eyelids which gives the patient a refreshed and more youthful look.   Fine incisions are made in the crease above the eye to rectify problems with the upper lids. [i] After removal of the fat, absorbable sutures are used to close the incisions.  Dr. Oestreicher uses a laser to perform this procedure as he feels that “the laser allows the incision to be made with less bleeding and bruising.  When performing lower lid surgery, the laser is used inside the lid thus eliminating the need for stitches.”  (1) The length of surgery is one to two hours in length and is may be performed under local or general anesthesia. 

 

Although Blepharoplasty is normally performed as a cosmetic procedure, it is also used to correct eyelid problems that can interfere with vision for younger people or for those whom have inherited droopy eyelids.  Dr. Oestreicher performs repair work or revision Blepharoplasty routinely and finds the most common mistakes are where the “surgeon has done the lower lids indelicately therefore resulting in the lower lids dropping out.” 

This procedure is of particular importance to the elderly age group as well since aging can cause the upper eyelids to sag and hinder vision.  Canadian statistics suggest that the top three cosmetic procedures most sought after for men include: liposuction, nose reshaping (Rhinoplasty) and Eye lid surgery.[ii]   

In the US, Blepharoplasty has become more popular than nose jobs, face lifts and forehead lifts with more than 230,000 people undergoing this procedure in 2006 alone.[iii]

 

Noreen Khan

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[i] Web MD Better Information.  Better Health.  Cosmetic Surgery for Eyelids—Information on Blepharoplasty from Web MD.

Available at:  http://www.webmd.com/skin-beauty/cosmetic-procedures-eyelid -surgery.  Accessed Jan. 17^th, 2008.

[ii] Medicard Canada’s Patient Financing Company. 

Available at:  http;//www.medicard.com/procedure_info.php.  Accessed Jan. 21^st, 2008.

 

[iii] Meronk Blepharoplasty- The 30 Basic Questions. 

Available at:  http:// www.drmeronk.com/main/blepharoplasty.html.  Accessed Jan. 23^rd, 2008.

ANATOMY OF THE NORMAL EYE

ANATOMY OF THE NORMAL EYE

 

Let's take a look at the human eye and explore the parts

and functions.

 

The eye consists of three layers referred to as 'TUNICS.'

 

 

1.  The FIBROUS TUNIC--This is the outside, tough protective layer.

This is made up of the (a.) Anterior --1/6 of the CORNEA--the cornea is clear and

                                       is avascular 

 

 

                                 (b.) Posterior --5/6 SCLERA--the sclera is opaque and

                                        vascular

 

2. The VASCULAR TUNIC--This is the middle layer which contains blood vessels.

This is made up of (a.) CHOROID--This is the brownish tissue that supplies blood  to the outer layer of the retina--this is held in place by the Vitreous Humour

 

 

                            (b.)  CILIARY BODY--black tissue that connects the choroid

                                    with the iris--this produces Aqueous Humour.

 

                            (c.)  IRIS--Circular structure of various colours --controls

                                   diameter of the pupil

 

3. The NERVOUS TUNIC--This is on the inside of the eye and is composed of receptor cells.

 

 

The CORNEA is transparent and covers the iris, pupil and anterior chamber.  Most of the eye's power comes from the cornea which has five layers.

 

The LENS or CRYSTALLINE LENS is the natural lens in the eye which is transparent and biconvex.  The lens is responsible for focusing light rays on the retina.  The lens is suspended by ligaments called zonules attached between the ciliary body.

 

AQUEOUS HUMOR--This is the clear, watery fluid that fills the space between the back surface of the cornea and the front surface of the Vitreous.  This liquid is produced by the ciliary process and nourishes the cornea, iris and lens.

 

VITREOUS HUMOR--This is the transparent, colourless jelly-like mass that fills the back two-thirds of the eyeball, between the lens and the retina.

 

 

 

 

 

 

 

 



VISUAL ACUITY--SNELLEN WHO?

SNELLEN CHART

We have all seen this chart before.  It is called the Snellen Chart.  It is the most commonly used chart to determine visual acuity.  This chart was developed by Herman Snellen in 1862.

When the eye is 20 ft from the chart and can read the 7th or 8th line clearly (depending on the chart used) then the eye is regarded as having 20/20 Visual Acuity.

20/20 = 6/6 metric conversion (meters)

Perhaps I should backtrack and explain what Visual Acuity means.

Visual Acuity:  Measurement –Assessment of the eye’s ability to distinguish object details and shape, using the smallest identifiable object that can be seen at a specified distance (usually 20 feet or 6 m)

The Numerator, or the number on top (first number) represents the test distance.  This is commonly 20 feet or 6 meters.  The Denominator, or the bottom number (second number) is the distance from the chart at which a person with normal vision can see the chart letters.

 

 

20/20—Means that a person can distinguish at 20 ft what a normally sighted person can see at 20 ft.   (normal vision)

20/50—Means that a person can distinguish only at 20 ft what a normally sighted person can see at 50 ft.  (worse )

What does 20/200 represent? 

 

 

 

 

 

 

 

3D VISION

 

 

 

Have you ever gone into a movie theatre to watch a 3D movie?  What was the experience like?

Not everyone has the ability to see in 3D.

But most people have the ability to see in 3D—or three dimensions.  This is called Depth Perception.  Depth Perception is the ability to distinguish the position of objects relative to spatial location of other objects.  Depth perception allows us to judge distances, size of objects relative to each other and allows us to avoid bumping into things. 

Some people do not have the ability to see in 3D.  They may have a condition called Amblyopia or Strabismus.  We will discuss this in a later post.

What is fusion?  Fusion, which is a function, is necessary to be able to see in 3D.

Fusion is the ability of the two eyes to see an object as a single image.  Eye movement coordinated to fuse two images into one

Eyes must be parallel when looking straight ahead.  This results in binocular vision.

Eye muscles must be coordinated and working in unison.  Each eye must have good vision.  A lot of people misunderstand 'normal vision' for 'perfect vision.'  I will discuss this later on.

 

 

 

 

 

 

 

 

Nearsighted/Farsighted, Huh? All Greek to Me!!

When speaking about vision and eyes, there are some common terms that we should discuss.

We often hear the terms nearsighted or farsighted.  But what do they really mean?

NEARSIGHTED

If you are Nearsighted, this simply means you  have trouble seeing clearly in the distance but close-up objects are clear.   The optical term for this condition is Myopia. 



NEARSIGHTED--MYOPIC EYE

A more in depth explanation is that when light enters into the eye from a distant object, it should focus the light rays on the retina once passing through the lens of the eye.   However, in this condition, the light rays focus in front of the retina.  There are a few reasons for this.  It can be that the eye is too long, or that the eye has too much optical power.  I will get into this bit later on.

This condition can easily be corrected by a licensed optician fitting the patient with corrective lenses.  A Minus lens (concave) when placed in front of the myopic eye, can help to extend the light rays from the image to fall on the retina behind the eye thus having a sharp, clear image of the object in sight.

 

FARSIGHTED

 

If you are farsighted, this simply means that you have trouble seeing objects clearly close up and that distant objects are more clear.    The optical term for this condition is Hyperopia or Hypermetropia.

 

FARSIGHTED-HYPEROPIC EYE

 

 

 

When light enters into the eye from a distant object, it should focus the light rays on the retina once passing through the lens of the eye.  However, in this condition, the light rays focus behind the retina thus the image is formed behind the retina.

 

In this condition, a Plus lens or Convex lens is required to help light rays shift and from behind the retina and on to the retina.

 

We will discuss the parts of the eye in the next blog. 

 

Changing Demographics

Changing demographics oblige us to take a close look at the eye care industry today.  Technological advances have brought about a significant shift in life expectancy.  The Canadian population is ageing, and life expectancy has increased; this will impact demand for eye exams and corrective vision wear in the coming years.  Forecasting data suggests that a very real crisis is looming in eye care as Canadian baby boomers age. 

 

Small retail operations will continue to function, and will certainly cater to a more senior target market.  However, the shift to a larger, elderly clientele will impact our capacity to service their eye care needs.  Proper future planning is critical to the years ahead.  The elderly are prone to particular eye diseases and conditions such as cataracts, diabetes, glaucoma, and macular degeneration.  All of these conditions need to be treated by ophthalmologists, of whom we are predicting a shortage in the future.   This can be addressed by encouraging the students of today to enter the ophthalmic field as their career of choice for tomorrow.

 

The future of our industry involves risk and uncertainty.  Current demographic trends will also create a multi-million dollar market for progressive lenses.  Our industry will also need to turn to new and innovative products and technology. 

 

Canada faces significant population ageing; this is a complex issue that concerns many broad areas such as heath, labour markets, public finances as well as the eye care industry.  What we do about it today, will inevitably affect us tomorrow.  

Let's Get Started

 

I wanted to start writing about your eyesight and vision in general.  I believe that a lot of people out there are oblivious to the optical industry and simply do not have the basic knowledge of what to do and how to care for the only set of eyes they have.
I will endeavour to enlighten you based on my own personal experience in writing about this field. 

For starters, I wish to speak about the three O's of the optical world.

1. Opticians
2. Optometrists
3. Ophthalmologists

Generally, in our industry when speaking to a client or customer, they are not able to easily discern between the three.  I will explain what each are and what each mean.

Optician:  This is a person whom has taken a course at the college level and is comparable to a pharmacist in that an optician can 'dispense' a prescription for eyeglasses or contact lenses.  Basically, an optician is a vision care specialist.  In order to legally dispense in the Province of Ontario, all opticians must be licensed if dispensing eyewear.  Seneca College offers the Ophthalmic Dispensing Program.

Optometrist:  This is a doctor of optometry (OD) and is generally the person you go see to get your vision tested.   An optometrist specializes in vision problems and can also treat various eye conditions and prescribe medications for eye diseases.

Ophthalmologist: This is a medical specialist or eye surgeon whom specializes in diagnosis and treatment of refractive, medical and surgical problems related to eye diseases and disorders.

There is a lot of buzz in today's world about laser eye surgery and about never having to wear your glasses again.  I will tackle this subject in an upcoming blog. 

What |I will leave you with is a dilemma that the eye care industry is facing.  Currently, we are facing an aging population and demographics suggest that there are a lot of people whom are all retiring in and around the same time.  They will all need health care and in particular, vision care.  The industry is currently not equipped to handle an onslaught of aging population. 

I will explore this topic on my next blog.

Noreen