Presbyopia shares visual similarities with hyperopia, but it is the farsightedness particular to older people, including those whose eyeballs are of normal shape. In presbyopia the power of the eyes to focus on near objects weakens, usually beginning around age 45. Reading small print becomes difficult. Almost everyone develops presbyopia in later years. All three refractive errors are readily corrected with glasses or contact lenses.
Laser surgery is a relatively new procedure that is being used for myopia in adults.
This is a condition in which the eyes move involuntarily with a jerky motion. The disorder is almost always present at birth and is of unknown cause. Vision is severely affected. Nystagmus that appears in later life may be an indicator of a nervous disease or brain tumor. Ptosis is a drooping of the upper eyelid, usually due to a weakness of the lid-lifting muscle or interference with the nerve that operates the muscle.