Symptoms
The first symptoms most people notice are difficulty reading fine print, particularly in low light conditions, eyestrain when reading for long periods, blur at near or momentarily blurred vision when transitioning between viewing distances. Many extreme presbyopes complain that their arms have become "too short" to hold reading material at a comfortable distance.
Presbyopia symptoms, like other focus defects, become much less noticeable in bright sunlight due to the action of the iris closing to a smaller diameter. As with any lens, increasing the focal ratio of the lens increases depth of field by reducing the level of blur of out-of-focus objects (compare the effect of aperture on depth of field in photography).
A delayed onset of seeking correction for presbyopia has been found among those with certain professions and those with miotic pupils. In particular, farmers and homemakers seek correction later, whereas service workers and construction workers seek eyesight correction earlier.
Read more about this topic: Presbyopia
Famous quotes containing the word symptoms:
“Murderous desire, hatred, distrust are nowadays the accompanying signs of physical illness: so thoroughly have we embodied our moral prejudices.—Perhaps cowardice and pity appear as symptoms of illness in savage ages. Perhaps even virtues might be symptoms.”
—Friedrich Nietzsche (1844–1900)
“For anyone addicted to reading commonplace books ... finding a good new one is much like enduring a familiar recurrence of malaria, with fever, fits of shaking, strange dreams. Unlike a truly paludismic ordeal, however, the symptoms felt while savoring a collection of one man’s pet quotations are voluptuously enjoyable ...”
—M.F.K. Fisher (1908–1992)
“In retirement, only money and symptoms are consequential.”
—Mason Cooley (b. 1927)