Macular degeneration is often diagnosed by an optometrist either as part of a routine examination or because the patient has gone to visit specifically as a result of distorted or blurred vision. The optometrist will measure the patient’s visual function and examine his eyes – using instruments such as a Snellen or Logmar chart, a slit lamp and one of the many varieties of ophthalmoscopes that provide a clear view of the retina of the eye. Many optometrists also have additional instrumentation to measure the presence and severity of macular degeneration – for example ocular computed tomography devices. These are sophisticated lasers that scan the retina and can ‘see’ beneath its surface. Using this technique, the abnormal blood vessels that are present in wet macular degeneration become visible, even though they cannot be seen by direct inspection with an ophthalmoscope. Another simple check used by both optometrist and ophthalmologists (eye doctors) is the Amsler Grid test. This is a crosshatch pattern on a piece of white paper with a central dot at which the patients stares. In the presence of macular degeneration, the straight lines of the grid appear curved, kinked, distorted or missing altogether. Optometrists will refer patients to an ophthalmologist immediately if either type of macular degeneration is identified.
What is the difference between the two types of macular degeneration – wet and dry?. Dry macular degeneration is a slow degeneration of the central part of the retina causing a characteristic ‘salt and pepper’ discolouration of the macula – the really essential, central area of the retina which is responsible for the finest and most precise type of vision. Dry macular degeneration usually takes many years to reach its final stages. As with wet macular degeneration, the final outcome of the dry macular degeneration variant is complete loss of the central area of vision. This unfortunately has a very severe impact on the patients quality of vision and therefore quality of life as it is this central area of vision that is essential for virtually every precise visual task that we undertake – seeing peoples faces, reading text, watching the television etc.
Whereas dry macular degeneration is a slow process, the wet macular degeneration variant is by contrast often very rapid. In this form, abnormal blood vessels grow into the macular area of the retina, burst and bleed causing catastrophic haemorrhage and permanent damage to the delicate cellular structure of the fovea (the fovea is the centremost and most important region of the macula).
Sufferers from macular degeneration, their relatives and anyone interested in ophthalmology and eye disease will be relieved to learn that there is now a successful treatment for wet macular degeneration – a treatment that frequently prevents the total blindness that this form macular degeneration used to cause. In this treatment a ‘monoclonal antibody’, either Lucentis or Avastin is injected into the eye. The ‘monoclonal antibody’ acts against the blood vessels that cause wet macular degeneration and makes them regress (disappear). Dramatic improvements in vision and often obtained and the advent of treatment for wet macular degeneration is one of the miracles of modern medicine.
If there is anything positive that can be said about macular degeneration it is the fact that it does not cause total blindness that includes the entire visual field. Only the central (admittedly by far the most important) portion of vision is damaged. The peripheral vision remains intact. This is extremely helpful because peripheral vision equals ‘navigating vision’ and patients with macular degeneration will always be able to negotiate their environment.
Although Eyesite is primarily a provider of ‘front of eye’ treatments, some of the surgical techniques used by Eyesite’s surgeon Dr Simon Levy are helpful to patients who do have macular degeneration. For example customised lens implant surgery can optimise the residual vision that patients with macular degeneration still have. To find out more, please contact Eyesite.
