Common Diseases

The health of your eyes isn’t just about your ability to see clearly.

Diabetic Eye Disease

Diabetes can cause damage to the eye’s light-sensitive lining, and the retina, and produce changes called Diabetic Retinopathy.

The retina is the delicate layer of blood vessels and light-sensitive cells positioned at the back of the eye similar to the film in a camera. Images we see are formed on the retina itself, converted into electrical impulses, and pass from the retina to the brain along the optic nerve.

The central part of the retina, opposite the pupil, is called the macula. This part is the most sensitive and allows us to see fine detail.

The rest of the retina sees the less well-defined images but gives us peripheral visual awareness, and movement sensation and helps us see at night. If the retina is damaged by diabetic retinopathy, the images formed on the retina are not detected by the light-sensitive cells, some of the electrical impulses are not transmitted to the brain and our vision is reduced.

In the retina itself, diabetes causes the walls of the smallest blood vessels to weaken, resulting in balloon-like bulges called microaneurysm. Bleeding from these tiny blood vessels, (retinal haemorrhages) or leakage of fats and fluid into the surrounding tissues may occur, which can result in vision reduction.

Lifestyle factors

Lifestyle factors play an important role in managing diabetic eye disease. This includes:

  1. Maintaining healthy blood glucose levels
  2. Maintaining a healthy blood pressure
  3. Avoiding smoking
  4. Maintaining healthy blood lipids
  5. A healthy diet and regular exercise.
  6. Having regular full diabetes eye checks
  7. Reporting any changes in your sight urgently.


As we get older many aspects of our vision change. Because of this, it is important to make regular visits to your optometrist. This is so your vision can be monitored.

Cataracts occur when the lens inside your eye becomes increasingly opaque resulting in ‘misty’ or ‘foggy’ vision.

What are some effects of cataracts?

Someone with early stages of cataracts may notice a ‘film’ in their everyday vision. Often things that used to look black and white now look grey and colours are perceived as dull.

In the early stages of cataracts, new spectacles may improve vision but, as the cataract worsens, spectacles often will not provide any significant improvement. Your optometrist will be able to advise you further on this. You may not be aware of cataracts in your vision because changes can be gradual.

As cataracts become more advanced, vision becomes ‘foggy’, less detail is seen, reading can be slower, television isn’t perfectly clear and driving becomes difficult when driving into the sun. At this stage, new spectacles will not restore ‘normal’ vision and often surgery is required.

Can cataracts be corrected?

Usually, the answer is yes. Corrective surgery removes the cataract (the cloudy lens), and an artificial lens is put in its place. This procedure takes up to half an hour and you are back at home a few hours later.

Macular Degeneration

Our vision changes as we age. This is why regular visits to your optometrist are essential. In this way, your vision can be monitored.

As we age, the retina (lining the inside of the back of the eyeball) begins to deteriorate, making it harder to see clearly. This is particularly true of the macula, the most sensitive part of the retina. When this region starts to atrophy, the sharpness of vision is lost and this can lead to difficulty with reading, and often, the need to give up driving.

Although macular degeneration can lead to serious visual impairment, it rarely results in total blindness. Treatment is limited and in most cases, prevention remains the best course of action. Laser treatment may be an option for some people, and new therapies are looking promising for the future.

The condition tends to progress slowly, and because prevention remains the best course of action, it’s important to schedule regular eye exams. Your optometrist will discuss ways to minimise your risk factors if they detect signs of macular degeneration.


Glaucoma is a disease of the eye that can occur at any age but is more common in older people. Glaucoma is one of the leading causes of blindness in New Zealand.

When diagnosed early, blindness from glaucoma is almost always controllable with ongoing treatment. In these situations, the likelihood of losing sight is reduced.

Glaucoma is commonly associated with increased pressure within the eye but the term glaucoma actually refers to a group of eye diseases in which the optic nerve is slowly destroyed. Learn more about Glaucoma and how it is treated below.