Signs and Symptoms
Age-related macular degeneration can be classified into ‘wet’ form and the ‘dry form’. In the dry (nonexudative) form, cellular debris called drusen accumulate between the retina and the choroid, and the retina can become detached. In the wet (exudative) form, which is more severe, blood vessels grow up from the choroid behind the retina, and the retina can also become detached.
- Pigmentary alterations
- Haemorrhages in the eye,
- Drastic decrease in visual acuity
- Blurred vision
- Drusen: tiny yellow or white accumulations of extracellular material that build up in Bruch’s membrane of the eye.
- Central scotomas (shadows or missing areas of vision)
- Distorted vision – A grid of straight lines appears wavy and parts of the grid may appear blank. Patients often first notice this when looking at mini-blinds in their home.
- Trouble discerning colours; specifically dark ones from dark ones and light ones from light ones.
- Slow recovery of visual function after exposure to bright light
What causes AMD?
Aging is a major contributing factor in developing AMD, approximately 10% of patients 66 to 74 years of age will have findings of macular degeneration. The prevalence increases to 30% in patients 75 to 85 years of age.
Family history is also a major contributing factor, it has been found that the lifetime risk of developing late-stage macular degeneration is 50% for people that have a relative with macular degeneration, versus 12% for people that do not have relatives with macular degeneration.
Genetics were also found to play an important role in the development of macular degeneration. The genes for the complement system proteins factor H (CFH) and factor B (CFB) and factor 3 (C3) have been determined to be strongly associated with a person’s risk for developing macular degeneration.
Mutation of the ATP synthase gene Retinitis Pigmentosa (RP) is a genetically linked dysfunction of the retina and is related to mutation of the Adenosine Tri-Phosphate (ATP) Synthase Gene 615.1617 . Additional factors that contribute to development of AMD are high blood pressure, high cholesterol, obesity and smoking.