The importance of eye tests

Do you find the thought of visiting your optometrist a bit daunting? We believe that if you know the importance and the necessity of the tests that we do, you will no longer be hesitant to visit us.

In this month’s newsletter we will provide a comprehensive overview of what a dilated eye exam is, how to care for your sunglasses, and we also have a very exciting announcement!

What is a comprehensive dilated eye exam?

You may think your eyes are healthy, but visiting an eye care professional for a comprehensive eye exam is the only way to really be sure. During the exam, each eye is closely inspected for signs of common vision problems and eye diseases, many of which have no early warning signs.

Annual comprehensive eye exams are generally recommended starting at age 60. However, people of African descent are advised to start having comprehensive  eye exams starting at age 40, because of their higher risk of glaucoma. Should specific eye health risks be noticed during a comprehensive eye examination, your optometrist might decide to do a dilated examination of the inside of your eyes. It’s also especially important for people with diabetes to have a comprehensive dilated exam at least once a year.

Key elements of a comprehensive dilated eye examination include dilation of the pupil with special drops, tonometry to check the eye pressures, a visual field test and a visual acuity test. We explore these elements in detail below:

Dilation: During a comprehensive eye exam the practitioner might notice risk factors which could affect the health of the eye inside. By performing a dilated eye examination, the pupil can’t constrict in response to the light used for the examination and a clear view of a larger area of the internal eye can examined. Drops placed in each eye widen the pupil, which is the opening in the centre of the iris (the coloured part of the eye). Dilating the pupil allows more light to enter the eye, the same way opening a door allows light into a dark room. Once dilated, each eye is examined using a special magnifying lens that provides a clear view of important tissues at the back of the eye, including the retina, the macula, and the optic nerve.


In a person with diabetic retinopathy, the most common diabetic eye disease and a leading cause of blindness, the exam may show swelling or leaking of blood vessels in the retina – the light-sensitive layers of tissue at the back of the eye. The eye care professional may also see abnormal growth of blood vessels in the retina associated with diabetic retinopathy.

In age-related macular degeneration (AMD), a common cause of vision loss and blindness in people over the age of 50, the exam may show yellow deposits called drusen, or clumps of pigment beneath the retina. In some cases, the exam may also show abnormal growth of blood vessels beneath the retina. These AMD-related changes tend to cause deterioration of a small area of the retina called the macula, which is needed for sharp, central vision.

A comprehensive dilated eye exam is also critical for detecting glaucoma, a disease that damages the optic nerve, which carries information from the eyes to the brain. In a person with glaucoma, the dilated exam may show changes in the shape and colour of the optic nerve fibres. The exam may also show excessive cupping of the optic disc, the place where the optic nerve fibres exit the eye and enter the brain.

Tonometry: a test that helps detect glaucoma. By directing a quick puff of air onto the eye, or gently applying a pressure-sensitive tip near or against the eye, your eye care professional can detect elevated eye pressure, which can be a risk factor for glaucoma. Numbing drops may be applied to your eye for this test.

Visual Field Test: measures your side (peripheral) vision. A loss of peripheral vision (tunnel vision) may be a sign of glaucoma.

Visual Acuity Test: will require you to read an eye chart, which allows your eye care professional to determine how well you see at various distances.

De Jongh Optometry: proud new stockists of Oakley Sunglasses!

We are very proud and excited to announce that we are now official stockists of Oakley Sunglasses.    (Images available at the following link:

What is Prizm?

Prizm™ is a new Oakley lens technology that fine tunes vision for specific sports and environments. Emphasising colours where the eye is most sensitive to detail, Prizm™ improves performance and safety by enhancing vision without the compromises of conventional lens tints. This is the first time lenses have been purpose-built for specific activities, and the benefits of this visionary technology are game changers. Why? Because it:

  • Sharpens visual acuity to help you see more clearly and react faster.
  • Enhances colour recognition to help you spot what you need to see.
  • Optimises your ability to see and track moving objects in your periphery.
  • Improves performance and safety to help you compete with confidence.

How to Care for Your Sunglasses

Winter might be approaching and heat systematically reducing, but the South African sun is still out in full force and its harsh light can still be damaging to your eyes if you don’t wear sunglasses, or if your sunglasses are of a low standard or quality.

We advise you to always carry or wear quality sunglasses with you to avoid the damage to your eyes that direct sunlight can cause. If you already own a decent pair of sunglasses, here are some tips to take care of them:

  • Sunglasses must be kept in their case at a temperature between -10°C and +35°C. Avoid exposure to the sun in closed environments without air conditioning (for example on the car dashboard) because the temperatures reached in such conditions can damage the functionality of the glasses. If the sun filters become worn (for example, scratched, opaque) it is recommended to replace them with authentic spare parts.
  • Always carry your sunglasses in a sturdy case when you’re not wearing them. To keep them in shape, use both hands to take them off and never put them face down onto a surface – scratches can be very annoying, or it can ruin your lenses. It’s best to avoid wearing them on your head as it can stretch the frame, causing them to slip forward on your face.
  • Keeping your sunglasses clean will ensure they look great and perform well. Sunglasses and especially their lenses require careful treatment. Improper care can damage lenses, resulting in scratches or haziness, which in turn may cause eyestrain.
  • The preferred method to clean your sunglasses is by gently rubbing them with a lens cleaning cloth and a liquid cleaner specifically designed for optical/sunglass lenses.
  • To minimise or avoid damage, never clean your sunglasses with paper towels or clothing, which can grind dust and fibres into lenses and eventually leave scratches on them. Please avoid using detergents and soaps, they are powerful enough to eventually disintegrate lens coatings. Glass and window cleaners are highly corrosive and can damage your lenses quickly. They are not designed for use on the non-glass lens materials used in sunglasses.

Be sure to make your eye exam appointment at De Jongh Optometrists today – our friendly and professional team will ensure that your eyes are very well cared for!

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