Eye Examination
There is more to an eye examination than finding out if you need spectacles or contact lenses. A range of tests are carried out to assess the health of your eyes. As everyone's eyesight is different, we tailor the eye examination to your individual circumstances. This may include the following elements and other tests where appropriate, based on the Optometrist's professional evaluation of your visual requirements. Click on the headings below to find out more..
We will ask several questions about your eyesight and general health - we are not being nosy! To be able to give you the best advice, it is important for us to know as much as we can about you and your eyes.
Many eye conditions are health-related e.g. diabetes. Several general health conditions exhibit signs in the eyes e.g. hypertension, high cholesterol. Hence it is important that you let us know if you are receiving treatment.
Many medications have side effects to the eyes e.g. steroids can increase the risk of cataracts and glaucoma. Therefore, it is important for us to know whether you are taking any medication (and what you are taking).
As some eye conditions can be hereditary, we will enquire if there is any family history of eye disease (e.g. glaucoma) or problems (e.g. squints or 'lazy' eyes). It is useful to know if you have suffered any injuries or accidents involving your eyes.
We will also need to know how you use your eyes at work and for leisure e.g. if you drive there is a legal visual standard and you may need spectacles to achieve this. If you are a VDU operator it may be necessary to prescribe special spectacles for VDU use.
If you wear spectacles you should bring these with you to your eye examination. The spectacles can be assessed and give us vital information to enable us to prescribe the correct prescription and suitable lenses. An instrument called a focimeter allows us to measure the spectacle prescription.
This is to determine whether you require spectacles - the familiar ' better or worse', ' red or green' subjective part of the examination.
We will check your distance vision (for driving or TV), your reading vision and if required your intermediate vision (for hobbies or VDU work).
Usually you will wear a ' trial frame' and different lens combinations will be given until your best vision is obtained. The standard of vision is usually measured by the smallest line of letters you can read correctly on a 'Snellen chart.'
Each eye has six muscles to control movement in all directions as well as the ability to cross our eyes. It is very important that both eyes work together to give comfortable, stable and single vision. These tests will check that both your eyes are coordinated and that you have comfortable vision at all distances. You may be asked to view a letter on a distant chart or a near object while your eyes are covered and uncovered. You may be asked whether a red line passes through a spotlight or whether it is above or below or to the side of the light. You may be asked to look at an OXO chart which measures muscle balance. You may be asked to follow a target such as pen-torch light around in all directions of gaze. If you have a minor eye co-ordination defect it can be corrected by incorporating prism lenses into your spectacles.
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The pupil controls the amount of light entering the eye. Your pupils will be larger in dim light and smaller in bright light. Your pupils should get smaller when you look at a near object. Your pupils should react equally ie both get smaller or bigger by the same amount and the rim of the pupil should be round and regular. An unusual pupil reflex can indicate neurological problems.
The Optometrist may use a Slit-lamp Biomicrosocope to examine the front structures of the eye, lids, conjunctiva, cornea. The anterior inner structures can also be examined, iris and anterior lens. Sometimes an orange dye (fluorescein) is put into the tear film to detect damage to the normally transparent cornea and surrounding tissues. With the use of an additional hand held lens (a Volk lens) a 3 dimensional image of structures at the back of the eye can be seen. This is particularly useful when assessing the optic nerve in a patient with suspect glaucoma.
This is a very important part of your examination because it checks the health of the eyes. Using a hand-held instrument (an Ophthalmoscope) a light is shone through the pupil into your eye. The Optometrist can see the internal parts clearly, including the lens, retina and optic nerve and therefore check for problems such as glaucoma, diabetes, cataracts, hypertension and macular degeneration. To facilitate a better view of the inner parts of the eye, sometime drops are put in to make the pupils larger - this is usually done where we are checking more peripheral areas of the retina for breaks and tears.
The Optometrist uses a hand held instrument (a Retinoscope) to shine a beam of light into your eyes. He carefully watches the light reflected back through your eyes and introduces different powered lenses. This is an objective assessment of your prescription and does not require you to do anything other than to watch a distant target. For certain patients the Optometrist can prescribe spectacles without the need for further questioning. For example:
- Very young children
- Patients who can’t speak English
- Stroke victims
- Patients with Dementia
- Disabled patients
