Eye Examination

An eye examination has three main functions:

  • To assess how well you can see and to prescribe spectacles should they be necessary.
  • To check how well your eyes work together.
  • To check the health of your eyes and to detect any general health problems that may be evident. Conditions such as diabetes, high blood pressure, kidney failure and many others that may be detected through an eye examination.

Your eye examination will take as long as is needed to ensure that we address every concern and question you may have. It will include the following:

We will ask you or your carer about your overall health, and that of your immediate family, as well as enquire as to the medications you may be taking.

It’s vitally important that we know how well you can see at present, any changes you or your carer have noticed to your vision, as well as any eye conditions that you have or have had in the past.

Some eye conditions can be hereditary, so we’ll ask if you know of any direct family members who have conditions such as Glaucoma or Macular Degeneration.

This history, and that of your family can give us an indication of any issues that may be affecting, or could affect, your vision.

The next stage is to examine the health of your eye, firstly the external eye will be assessed; the whites of your eyes (sclera), as well as the eyelids, pupils and eyelashes. Your binocular function and ocular balance will be checked, this involves a variety of tests conducted to investigate how well the eyes work together. Balanced, co-ordinated eyes are crucial for comfortable and sharp binocular vision. During this group of tests your optician will be looking for abnormalities such as strabismus (commonly known as a squint or turn in the eye), accommodation and convergence issues (focussing problems), eye muscle problems which may cause diplopia (double vision), all which may affect quality of vision.

From here we move on to the internal structures of the eye;

Special eye drops will dilate, or open, your pupil, which allows your optician to observe the inner parts of your eye, such as the retina and optic nerve. This can help to detect subtle changes of the optic nerve in persons without any visual symptoms and potentially lead to early detection of disease. Internal ocular health can be checked using a hand held microscope known as a direct ophthalmoscopy. This allows very detailed, binocular and magnified views of the back of the eye. The optician will inspect the optic nerve, macula, blood vessels and so on, looking for problems such as glaucoma and macular degeneration. We also use a Digital Retinal Camera to take a photograph of the back of your eye. Retinal photography is used to document retinal health at a particular point in time in a quick, objective and highly detailed manner. This enables accurate comparisons of eye health over time and meticulous monitoring of various eye conditions such as glaucoma, age-related macular degeneration and diabetic retinopathy. This is particularly beneficial when communication may be limited due to ongoing health issues.

Furthermore, we will check the pressure of the fluid within eyes. We use an instrument called a tonometer to do this. Tonometry is the measurement of tension or pressure within the eye. It is advisable for adults, particularly those over 40 to have their intraocular pressure (IOP) measured routinely as elevated IOP’s can lead to optic nerve damage. The optic nerve is a crucial part of the visual system; it collects all the visual information gathered by the photoreceptors of the retina and transmits this information to the brain, where the signals are interpreted as vision. Optic nerve damage can lead to decreased peripheral vision (tunnel vision) and loss of nerve tissues. Elevated IOP’s can commonly occur without symptoms, meaning like many other eye conditions the individual may be unaware there is a problem. Elevated IOP’s is associated with Glaucoma; as a result tonometry is important in diagnosing and monitoring Glaucoma.

Refraction helps determine the sharpness or clarity of both your near and distance vision. We will assess and measure how well you see with and without spectacles (if you currently have some) by asking you to identify letters, numbers, shapes and pictures (depending on age and reading ability) on a special test chart.

A retinoscope is then used to assess whether or not visual correction in the form of spectacles is needed. The retinoscope is a handheld device used by the optician allowing an accurate approximation of the level of myopia (short sightedness), hyperopia (long sightedness and astigmatism (rugby ball shaped cornea), you may have and will enable them to determine your required spectacle prescription. This process takes only a few seconds to perform, and involves the optometrist shining a light into the eye. The next stage involves wearing a special frame (a trial frame) in which we places lenses. This allows the fine tuning of your prescription to take place.

Visual field testing helps determine how much side (or peripheral) vision you have and how much surrounding area you can see. Visual field testing is particularly important in screening, diagnosing and monitoring retinal conditions such retinal detachments; optic nerve conditions such as glaucoma and optic neuritis; and brain disorders such as strokes and tumours.

The most common type of visual field test in a comprehensive eye exam is called a confrontation field test, in which the optician briefly flashes several fingers in each of the four quadrants (above, below, right, and left) of your visual field while seated opposite you.

If the optician requires to carry out a more precise measurement, then we have a computerized visual field screener. This involves looking at a small orange target within a white bowl. You are asked to maintain a constant and steady gaze on this target. The machine then presents a small white dot of light at random intervals and locations around the bowl and you are asked to press a button in response to having seen the light.

In threshold visual field testing the brightness of the white light presented varies throughout the duration of the test, meaning some lights are more difficult to see than others. This process allows the optometrist to produce a detailed sensitivity map of the visual field which can be used to accurately monitor changes or abnormalities in the visual field.