4 - Bad Eye
Summary
This chapter will concentrate on the common eye diseases and their treatment. I have dealt with the various eye illnesses in alphabetical order and not in any order of perceived importance; after all, they are all important, especially to those who have them!
Age-related macular degeneration
Age-related macular degeneration, usually referred to as ARMD (or AMD), occurs in a number of forms, but the disease restricts itself to the macula, the delicate and vulnerable part of the retina of the eye that is most concerned with central vision (see chapters 1 and 2; also Plate 4). The macula is dominated by the cone type of photoreceptor and it is these macular photoreceptors which are gradually lost in ARMD – and with them goes central vision. Humans rely so heavily on central vision that ARMD is extremely visually disabling to those who suffer from the complaint.
Features and effects
ARMD is one of those eye conditions, like glaucoma and cataract, that arise in the elderly and develop usually in people aged 50 or more. Patients with ARMD often have a history of a gradual deterioration in vision over a period of several years. Also what normally would be seen as regular straight lines might to them appear wavy, for example, the side of a door, the top of a wall or the slats in a wooden fence. Reading can be a problem because the centre of the visual field (what the eye takes in when staring at something, see chapter 2) may be blank or blurred. People with macular degeneration don't go completely blind but they are visually handicapped and ultimately they have no central vision left at all. There can be a dark and hazy area in the centre of the window of vision of an ARMD sufferer (Figure 4.1). As the macula is concerned with fine detail, loss of its function makes reading, writing and seeing small things extremely difficult. The macula also dominates colour vision so, with loss of its function, colours become much less bright, although their appreciation is not lost.
As people get older, material collects between the retinal pigment epithelial cells and the choroidal blood supply.
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- Information
- The Eye BookEyes and Eye Problems Explained, pp. 75 - 105Publisher: Liverpool University PressPrint publication year: 2000