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Common Eye Diseases and their Management - part 8

Các bệnh nhân trẻ tuổi hoặc hơn quan sát nhận thấy rằng các cạnh thẳng có thể nhìn kinked. Thông thường, một mắt bị ảnh hưởng đáng kể hơn khác, mặc dù cả hai mắt có thể bị ảnh hưởng đồng thời. Bởi vì quá trình thoái hóa được giới hạn các điểm vàng, các lĩnh vực ngoại vi vẫn không bị ảnh hưởng | The Ageing Eye 151 to read. Younger or more observant patients notice that straight edges might look kinked. Usually one eye is considerably more affected than the other although both eyes can be affected simultaneously. Because the degenerative process is limited to the macula the peripheral field remains unaffected and the patient can walk around quite normally. Difficulty in recognising faces or in seeing bus numbers is also a common complaint. The wet form occurs more commonly in Caucasians and about one-third of the patients give a family history of similar problems. Several preventable factors including smoking systemic hypertension cardiovascular disease and low antioxidant intake are associated with increased risk of AMD. In the early stages of dry AMD inspection of the fundus shows spots of pigment in the macular region. Drusen are also often seen Figure 19.1 . These are small round yellowish spots often scattered over the posterior pole. Unfortunately the word drusen has been used rather loosely in ophthalmology to refer to two or three types of swelling seen in the fundus. It is used to describe the rare mulberry-like tumours seen around the optic nerve head in tuberose sclerosis and it is also used when referring to the multiple shiny excrescences seen on the optic disc as a congenital abnormality. Drusen seen at the posterior pole of the eye as a senile change are also known as colloid bodies and perhaps this term is preferable. Figure 19.1. Drusen.EŨ Figure 19.2. Dry macular degeneration.CJ Under the microscope colloid bodies are seen as a degenerative change in Bruch s membrane. Drusen can have varying degrees of hyperpigmentation. Most eyes with drusen maintain good vision but a significant number will develop progressive atrophy of the retinal pigment epithelium RPE and choriocapillaris. This is inevitably associated with photoreceptor loss Figure 19.2 . There is usually a moderate loss of vision. This atrophic change in the RPE choroid and .