I deal with a lot of people who have suffered some kind of brain injury. It could be surgical, traumatic brain injury, brain tumour, or even stroke. My vocation is to make their lives better and easier through neuro-optometric rehabilitation or visual therapy.
A fundus examination is one of the most important ways of checking the health of your eyes, and is therefore part of every eye examination. It is used to assess the condition not only of the eyeball but also of all its protective organs – the eye muscles, the eye socket and the eyelid – and can help to detect many problems.
What is the fundus?
The fundus is the inner wall of the back of the eyeball, behind the lens. However, we cannot talk about it as a specific anatomical concept, as this area is very detailed. The light rays that enter through the pupil arrive here, and the retina, or optic disc, is also located here, along with the blood vessels that run through it. The central part of the retina is the macula lutea, also known as the yellow spot, which is responsible for sharp vision and colour perception. Another important component is the papilla, or optic nerve head, where the nerve fibres of the retina merge to form the optic nerve. If there is a problem with any of these parts, a fundus examination will reveal it, and more! It can even detect disease in deeper layers.
What can a fundus examination diagnose?
Because it covers a wide area and involves a lot of detail, it can reveal damage to the optic nerve and the blood vessels that run through it, but it can also show problems in the neuroretina and the macula. It can also highlight the presence of deposits, haemorrhages and blood clots that may be blocking the blood vessels.
- Congenital or acquired diseases of the optic nerve, such as glaucoma.
- Abnormalities in the blood vessels in the fundus of the eye, which may indicate other problems that do not affect the eye, such as high blood pressure or atherosclerosis.
- Lesions that can interfere with sharp vision. The most important example is macular degeneration, or calcification of the fundus.
- Eye diseases affecting the retina, such as retinal detachment.
How is a fundus examination done?
The first step in a fundus examination is for the ophthalmologist to apply a dilating eye drop to the patient’s eye, as this will allow them to see the area under examination more accurately and in more detail. This can cause blurred vision for a while after the examination and it is best to avoid bright sunlight, which can disturb the patient. For this reason, activities such as driving or certain jobs should be avoided for several hours.
During the procedure, the patient’s forehead and chin rest on a headrest while the doctor looks at the eyes through the examination device. A slit lamp, an ophthalmoscope or a front lens, which in this case does not touch the patient’s eyes, is used. However, there are cases where it is necessary to insert a contact lens on the anaesthetised eye surface to obtain more information about the condition of the area under examination.
While the slit lamp examination also helps to map the lens and the area in front of the iris, the ophthalmoscope allows the condition of the blood vessels and the optic nerve to be checked within the fundus examination. If the fundus examination results so require, further, different types of examination may be warranted.
In contrast to the above, no dilation of the pupil is necessary when using a fundus camera. In this case, the camera is able to take pictures of the fundus through a smaller pupil. The images are then displayed on the computer screen and used for evaluation.
When is an investigation justified?
As mentioned above, a fundus examination may be necessary for each individual complaint, but it can also be just part of the general eye examination. There are, of course, some symptoms which, if detected, should be specifically targeted for examination as soon as possible. This may be when you notice a change in your vision or its sharpness, when you feel pain in your eyes, or when you have a persistent headache for which there is no other explanation. It is also a good idea to have regular check-ups if you have high blood pressure, diabetes, atherosclerosis or glaucoma.