Disease name: Age-related macular degeneration (AMD)

ICD-10 Disease Code: H35.3231 - Exudative age-related macular degeneration, bilateral, with active choroidal neovascularization

ICD-10 Disease Group: H35 - Other retinal disorders

Age-related macular degeneration (AMD) is an eye disorder caused by genetic and environmental factors. AMD is one of the leading causes of vision loss in older people. Mild symptoms may manifest in an individual's forties or fifties, with distorted vision or vision loss usually prevalent in a person’s sixties or seventies, which progresses over time. Vision loss in AMD is caused by a gradual degeneration of light-sensing cells in the macula, a small area at the centre of the retina that detects light and colour. The macula is responsible for central vision. AMD primarily affects central vision, impairing an individual's ability to read, write, drive and recognise faces. Peripheral and night vision are usually unaffected, but a slower adjustment of vision to darkness and dim lights is often present during the early stages of the disease.

AMD is categorised into two major types: the dry form and the wet form. Approximately 85% of individuals with AMD are classified as having dry-form AMD, which is characterised by a buildup of yellowish deposits called drusen beneath the retina and progressive vision loss. In advanced stages, geographic atrophy occurs whereby areas of the macula deteriorate completely, resulting in severe loss of vision. Vision loss often begins in one eye and progresses to include both eyes. In approximately 15% of individuals with dry-form AMD, the disease will progress to wet form. The wet form is associated with severe vision loss that exacerbates rapidly. 

Wet-form AMD is also defined as exudative AMD or choroidal neovascularisation (neovascular).

Although many factors that contribute to AMD remain undiscovered, several genes have been identified to contribute to a person’s risk of developing the disease. Genetic variants within genes involved in the complement system, a system involved in immune response, have been implicated in the development of AMD. Furthermore, genetic variance in chromosome 10 has also been associated with an increased risk of disease onset. Both ARMS2 and HTRA1 have been implicated in studies. Several other genes have been associated with AMD, such as those involved in transport and processing of high-density lipoproteins (HDL) and genes associated with other forms of macular disease.

Approximately 8% of the global population shows signs of AMD. The disease currently affects about 170 million people worldwide, and its prevalence is expected to increase. AMD appears to affect European descendents more frequently than African Americans in the United States.

Neovascular (wet form) AMD leads to growth of abnormal and fragile blood vessels underneath the macula. The macula becomes damaged due to blood and fluid escaping the vessels, causing central vision to blur and distort. This form of AMD is associated with extreme vision loss that can progress rapidly. The most common early symptom is the distorted or ‘wavy’ appearance of straight lines. Individuals with AMD sometimes experience a small dark spot in their central vision that expands over time. 

Currently, no treatment exists to restore vision in advanced neovascular AMD.

Early AMD may be treated using a combination of vitamins, antioxidants, and zinc to prevent disease progression.

Other treatments for severe neovascular AMD include laser surgery, photodynamic therapy, and injections to prevent formation of new blood vessels in the eye.

• https://www.icd10data.com/
• https://www.orpha.net/consor/cgi-bin/index.php
• https://rarediseases.org/
• https://medlineplus.gov/genetics/
• https://www.cdc.gov/

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Age-related macular degeneration (AMD)