Colour Blindness

Do you think your colour blind? Do you find it difficult telling if colours are red and green, or blue or yellow? Do other people sometimes tell you that the colour you think you are seeing is wrong?

If so, these may be signs that you have a colour deficiency, which can be called colour blindness.

What is Colour Blindness?

Colour blindness is actually an incorrect phrase, as it is not a form of blindness at all. Rather, colour blindness is a deficiency in the way you perceive colours. With this problem, you have difficulty seeing colours such as red and green or blue and yellow.

Red-green colour deficiency is the more common type. It affects about 2-6% of all males. It is very rare in females.

Blue-yellow colour deficiency is very rare, but affects both males and females equally.

People who are colour blind don’t necessarily see the world in shades of grey. They are able to see a full range of colours, but certain colours appear very different or appear less pronounced than what a person with normal colour vision would see.

If you suddenly develop a colour vision problem where you could previously see a wide range of colours, you should consult your optometrist or ophthalmologist. This could be due to other underlying health problems.

Colour Blindness Test Video

Causes of Colour Blindness


Colour blindness occurs when light sensitive cell in the retina (called cones) fail to respond appropriately to certain wavelengths of light that allow us to see colour. There might be a deficiency in these cones or a complete lack of them. This is normally inherited, so most people with colour blindness are born with it.

Parkinson’s Disease

It is a neurological disease so light sensitive cells may be damaged and results in colour blindness.


The lens becomes cloudy causing hazy vision and colours appear less bright. Cataract surgery will normally restore colour vision in this case.

Tiagabine for Epilepsy

This medication has been known to reduce colour vision, but its effects are not permanent.


Retinal cells can be affected as we age, decreasing our colour vision.


An injury to the back of the head could also result in colour blindness.

Treatment for Colour Blindness

Unfortunately, there is currently no cure for colour blindness.

Gene therapy has been successful in curing colour blindness in monkeys, but this has not been proven to be safe in humans as yet.

Most people who are colour blind adapt quite well but others have their career choices slightly limited. If you had to consider a career as a graphic designer or an electrician, you would be required to have very good colour vision.

If you become aware of your colour blindness at an early age, you can plan and train for your profession that does not require you to have a full range of colours.

Diagnosing colour vision problems early in life may also prevent learning problems as a lot of learning material at a younger age is dependant on colour perception. If your child is colour blind, the teacher needs to be aware of the problem so he/she can plan the lessons accordingly.

For adults, you can always work around your colour vision problems, like organizing your clothes in a certain order or labeling them to prevent colour clashes. Wearing 2 different coloured socks can be quite embarrassing. So get someone to help you.

Make sure you visit your optometrist or ophthalmologist if you need more advice on colour vision or if you’ve noticed problems in your children.

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    Eye Floaters

    Eye floaters are those tiny cobweb like spots that float around in our field of vision. In most cases they are harmless and are no need for concern.

    When we are born, the vitreous (jelly-like fluid at the back of the eye), has a gel-like consistency. As we get older, this gel starts to dissolve and becomes more liquid. Some undissolved gel-like particles float around in the more watery centre. They may be many shapes and sizes and this is what we refer to as floaters.

    These floaters are more noticeable when looking at a white wall or computer screen or at the bright sky. What we are seeing is actually shadows of the floaters reflecting on the retina. Also, they never stay still. They are always moving as your eye moves.

    When are Floaters an Emergency?

    If you notice a shower of floaters and spots accompanied with flashes of light, you should seek medical attention immediately. This means that the vitreous is pulling away from the retina causing a retinal tear, which could lead to a retinal detachment. Retinal detachments can lead to severe permanent loss of vision. An ophthalmologist needs to be consulted immediately to reattach the retina and prevent blindness.

    Light Flashes

    When the vitreous pulls against the retina, it causes flashes of light. These flashes may be short lived or continue until the retina is repaired. Sometimes, flashes are also caused after a blow to the head. Some people notice flashes where the light is wavy or jagged, which continues for 20-30 minutes. This is caused by spasm of the blood vessels in the brain. If this is accompanied by a headache, it is a migraine headache. If it is not accompanied by a headache it is called an ophthalmic migraine.

    Treatment for Floaters

    Most floaters are not serious and require no treatment. They will fade over time and become less bothersome. Eye specialists will only consider removing them if they are so many that they disturb your vision. This is done by a procedure called a vitrectomy. The vitreous gel is totally removed from the eye together with the floaters. The gel is usually replaced with saline.

    Remember, the sudden appearance of a significant number of floaters accompanied by flashes of light could indicate a retinal detachment and is a medical emergency which requires immediate treatment.

    If you suddenly see floaters, visit your optometrist or ophthalmologist immediately.

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      Age and Night Vision Driving

      Decreased night vision can be a serious traffic hazard, especially among older motorists who drive after dark.

      Unfortunately, the grading of vision screening for driver’s license renewals in our license departments means that large numbers of drivers in this age group may not be seeing their optometrist or ophthalmologist frequently enough to ensure their vision is adequate for safe driving.

      A bigger problem is that age-related eye problems, such as cataracts, can develop so slowly that older drivers may be unaware that their vision is declining.

      Road Traffic Accidents and Older Drivers

      Research has shown that although younger drivers are more likely to cause serious motor vehicle accidents resulting in death, older car drivers are a public health issue, because of age-related declines in vision, cognition and motor function. This makes them more susceptible to car crashes in complex situations that require good visual perception, attention and rapid response.

      A typical car driver makes about 20 decisions every kilometre and has less than half a second to react fast enough to avoid an accident. Age affects the 3 essential steps involved in that reaction process: sensing, deciding and acting.

      Also, traffic deaths are 3-times more likely to occur at night than during the day.

      Why is Ageing and Night Driving a Problem?

      As we age, our eyes usually begin to fail long before we notice it.

      • Pupils shrink and don’t dilate as much in the dark as we age. This reduces the amount of light entering the eye. The retina receives far less light. This can make older drivers function as though they are wearing sunglasses a night.
      • The cornea and lens in the eye become less clear with age, causing light to scatter inside the eye, which increases glare. This makes it harder to see objects on the roads at night.
      • An older person may test well in the optometrist’s office but still struggle to focus on the road at night, where lighting is poor and more complex vision tasks are required.

      • Older eyes have a higher risk of developing eye diseases like age-related macular degeneration, glaucoma, diabetic retinopathy and cataracts.

      These eyesight problems, together or in isolation, may cause a gradual decline in vision and so a driver doesn’t realize that he has become visually impaired.

      Despite these many reasons for concern, many older individuals ignore the need for regular eye exams. Taking responsibility for your eyes by having regular eye examinations is the best way to ensure you have the visual abilities needed for safe driving as you get older.

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        Presbyopia – Reading Difficulties

        Ever heard of presbyopia? If you’re over the age 40, you have probably noticed changes in your vision. Most noticeably, would be changes in your near vision. This is called Presbyopia. It is the normal age-related loss of near focusing ability.

        When you develop presbyopia, you may find that you need to hold books, magazines, newspapers, menus and other reading material at arms length in order to focus clearly. Near work, like writing or sewing may cause headaches, eye strain or you may feel tired.


        What Causes Presbyopia?

        Presbyopia is caused by an age-related process. It is due to the loss of elasticity and hardening of the natural lens inside your eye. As a result the eye has a harder time focusing up close. It differs from astigmatism, short-sightedness or far-sightedness, which are related to the shape of the eyeball and are caused by genetic and environmental factors.

        Treatment Options for Presbyopia

        The best way of treating presbyopia is with eyeglasses. Surgery is the other option.

        Eyeglasses with bifocal or multifocal (progressive) lenses are the most common correction for presbyopia. Bifocal lenses have 2 focus points:

        1. The upper portion of the spectacle lens is designed for distance vision,
        2. The lower portion of the lens is designed for near vision.

        The two portions of the eyeglasses are separated by a line.

        Multifocal (progressive) lenses have a more gradual vision change between the two prescriptions, with no visible line between them.

        Reading glasses are another choice. Unlike bifocals or multifocals, which you would wear all day, reading glasses are worn just during close work.

        If you wear contact lenses, your optometrist can prescribe reading glasses, which you wear while your contact lenses  are in.

        Multifocal contact lenses are also an option. These contact lenses work just as multifocal eyeglasses would, giving you clear vision at all distances.

        Monovision is an option where one eye is corrected for distance and the other is corrected for near.

        Your optometrist will discuss the best option for you.

        The natural lens in your eye continues to change as you get older. Therefore, your presbyopia prescription will need to be increased over time as well. Your optometrist will prescribe a stronger correction for near work as you need it.

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          Age-Related Macular Degeneration

          Age-related macular degeneration often called ARMD is very common cause of vision loss and blindness among the elderly. It is the degeneration of the macular, which is the area of the retina that gives us sharp central vision which we use when driving, reading etc… Degeneration of the macular, therefore affects our central vision.

          There are 2 forms of macular degeneration. Dry (non-neovascular) or wet (neovascular). The term neovascular here means the growth of new abnormal blood vessels in an area. The dry form is more common than the wet form, but the wet form results in much more serious vision loss.

          Dry Macular Degeneration (non-neovascular)

          Dry ARMD is the early stage of the disease. It is due to the thinning and deterioration of the tissues surrounding the macular. We find yellowish deposits called, drusen, surrounding the macular. These drusen deposits are from the deteriorating macular tissue. Slowly, you start losing your central vision. Over a period of years it can cause severe vision loss.

          Studies have shown that vitamins A, C and E, can slow down the progression of dry macular degeneration. Therefore, the use of eye vitamins can reduce the risk of getting macular degeneration.

          Wet Macular Degeneration (neovasvular)

          Sometimes, dry ARMD will progress to the more advanced and damaging form of the disease, wet ARMD. With wet ARMD new abnormal blood vessels grow underneath the retina. These blood vessels are weak and start to leak blood onto the retinal cells which die off. This causes blind spots in your vision.

          The growth of new blood vessels is the body’s way of providing more oxygen and nutrients to the area. Unfortunately, because these blood vessels are abnormal, they leak and cause scarring, leading to severe vision loss.

          How do I know if I have Macular Degeneration?

          Macular degeneration usually results in a slow painless loss of vision. Symptoms you may notice of macular degeneration are:

          1. shadowy areas in your central vision
          2. unusual distorted, fuzzy vision.

          Your optometrist or ophthalmologist will be able to detect changes in the macular area before you notice any symptoms. This is done by:

          1. Retinal exam and,
          2. Amsler grid.

          An Amsler grid is a chart consisting of black lines in a grid pattern.

          If changes are detected, a fluorescein angiography will be done to examine the retinal blood vessels around the macular.

          Causes and Risk factors for developing Macular Degeneration

          • Age

          • Hereditary

          • Being caucasian (white) and female. ARMD occurs more often in the white population and because they have a lighter eye colour, they are at higher risk from UV damage.

          • Obesity and inactivity

          • Sun over-exposure

          • High blood-pressure

          • Smoking

          • Drug side-effects

          Treatment of Macular Degeneration

          There is currently no cure for macular degeneration, but some treatments are available which may slow down the progression of the disease.

          The only treatment for the dry form of macular degeneration is nutritional supplements which may prevent its progression to the wet form.

          Zinc, lutein, vitamins A, C and E have been shown to reduce the risk of developing macular degeneration and prevent its progression to the wet form.

          For wet macular degeneration, treatment is aimed at stopping the growth of the abnormal blood vessels. This is done by the use of drugs injected into the eye. Certain drugs have been shown to improve vision lost to macular degeneration.

          So, if you feel you may have symptoms of macular degeneration, or there is a history of the disease in your family, schedule an appointment with your optometrist or ophthalmologist as soon as you can.

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            Cataracts of the Eye

            A cataract occurs when the eye’s natural lens becomes cloudy. The lens is situated behind the iris (coloured part of the eye). The lens works just as a camera lens works. It focuses light coming through the eye onto the retina. It also changes shape, adjusting focus, allowing us to see clearly from near to far.

            As we get older small areas of the lens starts to become cloudy, preventing light from going through to the retina. With time larger areas of the lens become cloudy making it more difficult to see.

            Signs and Symptoms of Cataracts

            In the initial stages, cataracts may have little effect on your vision. As it grows, you may notice your vision become a little hazy, like looking through a misty window. Sunlight and indoor lighting looks a little brighter than normal. Night driving becomes difficult as oncoming headlights cause a lot of glare. Also, colours are not as bright as they were before.

            Some types of cataracts don’t cause any symptoms until it is quite mature. Other cataract types sometimes result in an improvement in your near vision, called “second sight”. This improvement is short lived as your vision deteriorates as the cataract grows.

            If you think you have a cataract, visit your optometrist or ophthalmologist for an exam to find out for sure.

            Causes of Cataracts

            • The most common cause of cataracts is ageing.
            • Exposure to ultraviolet light. Optometrists always recommend the use of sunglasses to minimize your eye’s exposure to the sun
            • Other types of radiation

            • Diabetics. Being diabetic increases your risk of developing cataracts.
            • Using steroids
            • Eating a lot of salt. Diets high in antioxidants, vitamins A, C and E may slow down cataract development.
            • Cigarette smoke and alcohol consumption.

            Treatment of Cataracts

            In the initial stages a change in your spectacle prescription may improve your vision. As the cataract grows, the only option is surgery. Surgery is normally recommended when the cataract has grown to a point where it significantly impairs your vision and affects your daily life.

            Cataract Surgery

            Cataract surgery is very successful in restoring your vision and it is relatively painless. During surgery, the surgeon removes the cloudy lens (cataract) and replaces it with an intra ocular lens (artificial lens). If you have cataracts in both eyes the surgery is done one eye at a time, usually a few weeks apart.

            After surgery, the eye is covered with a protective shield and within a few hours you will be ready to go home. You will need someone to drive you.

            Over the next few weeks you will need to administer eye drops daily and wear sunglasses to protect you from glare. You may have slightly blurry vision which will improve as the eye heals.

            During the first few weeks try to avoid any heavy lifting or strenuous activity like exercise. Also, try to avoid swimming pools and hot tubs as they can cause serious eye infections.

            Complications during or after cataract surgery is , but sometimes does happen. However, even serious complications can be resolved with appropriate follow up treatments.

            Many people consider poor vision an inevitable fact of ageing, but cataract surgery is a simple, relatively painless procedure to regain vision.

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              Diabetes and the Eye

              Are you worried about diabetes affecting your eyes and vision. Well today we will be talking more about the effect diabetic patients may experience with their eyes. So the first question to answer is “What is Diabetes?”

              In diabetes, there is too much sugar in the blood.

              When the blood sugar is constantly or frequently high, many complications occur: eyesight can suffer, heart attacks and other blood vessel problems can occur, and one’s lifespan can be shortened. When the blood sugar is maintained at a normal level, the complications of diabetes including serious diabetic retinopathy can be reduced. Controlling blood sugar is the single most important thing a person with diabetes can do to prevent the complications of diabetes.

              Type 1 diabetes usually occurs at a young age. People with Type 1 diabetes must take insulin to survive and to control blood sugar. They should test their own blood sugar levels with a glucometer several times a day so they can adjust their diet, exercise, and insulin doses to keep the blood sugar at the required level. They should follow a diet controlled in carbohydrates and low in fat and cholesterol. Regular exercise is also important as it helps reduce blood sugar.

              Type 2 diabetes usually starts in adult life and is often not dependant on insulin for control of blood sugar. Maintaining normal weight and a diet low in calories, fat and cholesterol is very important. Blood sugar can be controlled either with diet alone or in combination with pills to lower blood sugar. In some cases, insulin treatment is also necessary.

              In addition to the importance of diet and exercise, there are other factors that can affect diabetes. High blood pressure is very bad for people with diabetes because it increases the risk of complications, including vision loss. Smoking is known to be particularly bad for people with diabetes because it promotes the closure of blood vessels.

              What is Diabetic Retinopathy?

              Diabetic Retinopathy is the most common eye disease associated with diabetes. In diabetic retinopathy, the blood vessels of the retina become abnormal and this causes the problems that people with diabetes have with their eyesight. Normally, the blood vessels of the retina do not leak. But with diabetes, the retinal blood vessels can develop tiny leaks. These leaks cause blood to seep into the retina. The retina then becomes wet and swollen and cannot work properly. The form of diabetic retinopathy caused by leaking retinal blood vessels is called Nonproliferative Diabetic Retinopathy (NPDR).

              Another problem with the retinal blood vessels in diabetes is that they can close. The retinal tissue which depends on those vessels for nutrition, will no longer work properly. This causes the growth of new abnormal blood vessels, which can be very bad for the eye. These new blood vessels are weak and can cause bleeding and scar tissue which can cause blindness (total loss of vision). This type of retinopathy which causes closure of blood vessels and the growth of new vessels is called Proliferative Diabetic Retinopathy (PDR).

              Nonproliferative Diabetic Retinopathy (NPDR)

              In diabetes, the retinal blood vessels can develop tiny leaks. Blood and fluid seep from the retinal blood vessels and fatty material deposits in the retina. This causes swelling of the retina, and it is called nonproliferative diabetic retinopathy (NPDR).

              When this occurs in the central part of the retina (macula), vision will be reduced or blurred. Leakage elsewhere in the retina will have no effect on vision.

              A patient with a wet, swollen macula, or with exudates in the macula, will have some loss of vision, including blurring, distortion, or darkening. If one eye is affected, the other eye may also be affected, though the problem may not be equally severe in both eyes. If diabetic retinopathy has affected each macula severely, central vision may be lost from each eye and the ability to see detail will be lost. These patients learn to use the areas outside the macula to see some detail. This ability to look slightly off centre usually improves with time, though the eyesight will never be as good as it was before the central retina (macula) was damaged by leaky blood vessels. So people who have NPDR will usually be able to see well enough to take care of themselves and continue those activities that do not require detailed vision.

              Proliferative Diabetic Retinopathy (PDR)

              In PDR, retinal blood vessels close off and large areas of the retina lose their source of nutrition. When this happens, peripheral or side vision is reduced, and the person’s ability to see at night and adjust from light to dark is often diminished.

              As a result of this loss of nourishing blood flow, the retina responds by developing new blood vessels that are abnormal. This can be a huge problem and can be very dangerous to the eye. These new vessels do not nourish the retina properly and may start to bleed and cause scar tissue on the retina. The scar tissue pulls the retina off the back of the eye and causes a detachment. This can lead to severe vision loss or even total blindness.

              Sometimes these new blood vessels can also grow on the iris (coloured part of the eye), and it may close off the normal flow of fluid out of the eye. This results in increased pressure in the eye and causes glaucoma. This causes permanent changes, resulting in vision loss, pain, and even total loss of the eye.

              It may be impossible for a person with diabetes and early PDR to know that any of these changes are occurring. For this reason, it is essential that every person with diabetes be examined regularly by an ophthalmologist or optometrist. These examinations should occur regularly, every 6-12 months, depending on the degree of retinopathy. The earlier theses changes are discovered, the better the chance of saving vision. The later these changes are discovered, the greater the chance of blindness.

              Treatment of Diabetic Retinopathy

              Laser Surgery

              Laser surgery can be very helpful in the treatment of diabetic retinopathy. The laser beam is a high energy light that turns to heat when it is focused on the parts of the retina to be treated. In NPDR, the laser seals the leaking blood vessels or reduces the leakage and allows the retina to dry. In PDR, the laser destroys the diseased portions of the retina to stop the growth of the abnormal new blood vessels.

              Essentially, the major purpose of laser surgery is to prevent further vision loss. Laser surgery may not always be best or even possible. The decision to use laser depends mostly on the type of diabetic retinopathy, its severity, and a judgment regarding how well it may respond to laser surgery.

              Because diabetes is a condition for which there is currently no cure, the diabetes may continue to damage the retina. Even with laser surgery patients may continue to lose vision. But when laser is the right treatment, the chances are that it can prevent further visual loss.

              Questions about Laser Surgery

              What is the purpose of laser surgery?

              In NPDR, the leaking blood vessels cause the retina to become wet and swollen, causing vision loss. Laser surgery stops the leakage from these vessels to prevent vision loss.

              In PDR, the growth of new abnormal blood vessels causes severe visual loss by bleeding into the eye and forming scar tissue which pulls on the retina causing a retinal detachment. The laser stops this growth and detachment and thus prevents further visual loss.

              Will I have to go to hospital?

              Laser surgery is usually done in the doctor’s office or in the hospital as outpatient surgery. After the surgery, you will be able to go home and resume your normal activities without special restrictions.

              Is the surgery safe?

              In most cases, no complications occur but, as with all surgery, there are some risks. There is a small chance that the laser beam might not be aimed properly and that healthy retina might be destroyed and vision lost. Laser might also cause bleeding and scarring. Fortunately, these complications are rare.

              What are the after effects of laser surgery?

              Certain types of laser surgery may cause loss of night vision. So these patients might not be able to drive at night. Sometimes peripheral or side vision may be reduced after surgery. Most patients have some degree of blurring of central vision which passes with time but in a few patients it may be permanent. Rarely, there is a lot of swelling after surgery which causes an increase in eye pressure. This is very painful and the patient should call the treating ophthalmologist immediately.

              Are the effects of the laser permanent?

              In most cases, leaking blood vessels remain closed and the growth of new abnormal blood vessels is stopped permanently after surgery. But because diabetes continues, it is common for the leakage to develop in new areas. If laser surgery is indicated, however, the outcome is always better than if no surgery is done.

              Does laser surgery cause any pain?

              For NPDR, laser surgery is almost always painless, though a few patients do experience some discomfort. After the laser surgery, the eye is patched for the rest of the day. In PDR, many patients experience some pain. The eye is usually anesthetized.

              How long does laser surgery take?

              Depending on the extent of the problem, laser surgery for NPDR may take anywhere from a few minutes to a half hour. For PDR it may take from 15 minutes to an hour or more.

              What will my vision be like after laser?

              Vision is often blurred but it usually improves within a month. There will be small black areas or blind spots where the laser spots were placed. These will be permanent but become less noticeable with time. Peripheral and night vision is likely to be reduced.

              How many treatments will I need?

              For NPDR, usually one treatment is all that is required. However, if new leaks develop later, additional surgery will be necessary. For PDR, two or three sessions are usually required.

              Can anything help if central vision is lost in each eye?

              Those patients who have lost central vision in both eyes will be referred to a low vision specialist who helps patients learn to use their remaining vision to its fullest. They make use of low vision aids like magnifying lenses, telescopic lenses, special filters etc.

              Will using my eyes hurt them?

              You cannot hurt your eyes by using them. There is no way in which using your eyes can do your eyes any harm, whether by reading, watching television or driving.

              Diabetes and Your Eyes

              If there is a fairly large, rapid shift in your blood glucose level, you may notice that your vision becomes blurry. This may occur prior to the diagnosis of diabetes, or it may develop after the initiation of treatment or a change in treatment of diabetes. This difficulty with vision or focusing will disappear once the blood sugar has been stabilized for about 1 week. So, measure your own vision in each eye, separately, each day. Know what you can see each day. If you notice a change in your vision, call your optometrist or ophthalmologist for an appointment. It is important for all patients with diabetes to have a thorough retinal exam regularly, about every 6-12 months, even when there are no problems. Also, be sure to talk to your own medical doctor about the importance of diet and exercise and the dangers of smoking and high blood pressure. And, most of all learn to maintain the best possible control of blood sugar.

              Pineslopes Optometrists will always be available to answer your questions and to help in every way possible. You are encouraged to call with any unusual symptom or worry. We are here to help you.

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