This Disease Can Cause Vision Loss

Age-related macular degeneration, a condition that emerges due to structural deterioration in the region called the 'macula' responsible for central vision, can lead to vision loss over time. Yellow spot disease, which begins due to the ageing process and other causes, often goes undiagnosed until stages 2 and 3 because it produces no symptoms in its early phase. Memorial Kayseri Hastanesi Göz Hastalıkları Bölümü Associate Professor Selim Demir provided information about yellow spot disease and its treatment.

Occurs in the nerve layer

The disease that occurs in the nerve layer, approximately the size of a lentil, which provides sharp vision to the eye, is called yellow spot disease. In the retina (nerve cell) layer located at the back of the eye, nerve cells are not present in equal density everywhere. The centre where light rays focus on the eye is called the 'macula' and is the area responsible for sharp vision. The macula is protected from excessive light damage by yellow pigments specific to the eye called lutein and zeaxanthin. Due to the colour of these pigments, this area is called the yellow spot. This region covers approximately 5% of the retina by area but is responsible for nearly 95% of visual function. In short, there is very high metabolic activity in a small area. As a result of intense metabolic activity throughout life, the macula (yellow spot) becomes unable to clear its toxic waste and the nutrition of retina cells deteriorates. The loss of function and death of nerve cells that cannot be nourished is called yellow spot disease.  

Can cause sudden vision loss

Yellow spot disease has two different types called 'dry type' and 'wet type'. Dry type is the most common form of yellow spot disease. The dry type fortunately shows slow progression. In many patients, it takes more than 10 years from the onset of the disease to reach an advanced stage that severely affects vision. In the dry type, the accumulation of metabolic waste that cannot be cleared beneath the yellow spot creates white-yellow coloured pointwise lesions called 'drusen'. As these increase, nerve cell damage increases and vision decreases. The wet type of the disease, unfortunately, causes serious and sudden vision loss. The resulting vision loss is painless. Wet type occurs as a result of abnormal uncontrolled blood vessels and bleeding and leakage from these vessels, caused by vascular growth factors (VEGF) secreted due to impaired nutrition in the yellow spot region.  

More common in people aged 60 and over

This is a disease of advanced age. As we age, if we cannot do many things as we used to, our visual function also decreases with ageing. The yellow spot, which is the most active region of the eye, loses its former performance with ageing. This disease is seen more frequently especially in people aged 60 and over. Genetic predisposition, exposure to sunlight and smoking are among the risk factors. Since the disease is progressive in nature, there may be lighter and vague symptoms in the early stage, while complaints increase in advanced stages.  

Blurriness while reading books may be a sign of yellow spot disease

Lines appearing slanted and objects appearing larger or smaller than they are are among the early symptoms of the disease. In particular, the indentation or tilting of text in certain areas while reading a book is a sign of yellow spot disease. Blurred vision and inability to see the centre of the point of focus clearly while being able to distinguish the periphery are pictures seen at more advanced stages. In glaucoma (eye pressure) patients, narrowing of the visual field at the periphery is observed due to damage, while the opposite occurs in yellow spot disease. That is, patients can see the periphery but have difficulty seeing the centre.