Merriam-Webster Collegiate Dictionary - macular degeneration

 noun  Date: 1918 a gradual loss of the central part of the field of vision usually affecting both eyes that occurs especially in the elderly and that in a slowly progressing form is marked especially by accumulation of yellow deposits in and thinning of the macula lutea and in a rapidly progressing form by scarring produced by bleeding and fluid leakage below the macula lutea