Review of ciliary muscle effort in presbyopia.
Fincham's theory of presbyopia would require maximum ciliary muscle contraction to produce maximum accommodative response at all ages. The Hess-Gullstrand theory, however, would allow a maximum accommodative response with a decreasing ciliary muscle contraction as age increases leaving a reserve ability of ciliary muscle to contract with age. If Fincham's theory is correct, a mild parasympatholytic drug would produce a decrease in the amplitude of accommodation, a mild parasympathomimetic drug would produce an increase in the amplitude of accommodation, and the AC/A ratio would increase with age. The results of this study indicate that all three of these do occur and therefore support the Fincham concept of the cause of presbyopia.
D000065:Accommodation, Ocular / Q000187:drug effects; D000328:Adult; D000367:Age Factors; D002924:Ciliary Body / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D010277:Parasympathomimetics / Q000494:pharmacology; D011305:Presbyopia / Q000209:etiology* / Q000503:physiopathology
D010277:Parasympathomimetics