Articles abound on telescope optics maintenance, but fingers on one hand are enough to count articles on eye maintenance. More importantly, few, if any, articles are written on preventing the most common eye problems. By age 65, over 22 percent will have definite evidence of cataracts, common eye-lens clouding. A brief description will clarify common preventable problems. The eye lens slowly becomes cloudy and eventually opaque.
Cataracts involve oxidation of the clear, transparent lens proteins.
They are correlated with excess exposure to ultraviolet light, so always wear dark glasses in the sun. Cataracts are accelerated by smoke, smoking, volatile solvents, and mostly by poor dietary habits, specifically inadequate amounts and varieties of vegetables and fruits. The contrast of extended objects also suffers markedly, especially in dim light. Low vision means you lose a magnitude or so when looking at the stars or can't see subtle details on planets. Low vision occurs in the eye retina, a very highly specialized nerve tissue that is an extension of brain tissue.