Hypermetropia: Refractive error in which parallel rays of light from infinity are focused behind the retina when the accommodation is at rest. The person can see distant objects but has problems seeing near objects
Accommodation: Changes that occur in the shape of the lens for seeing objects clearly at near distances
Lasik: A type of laser procedure on the eye to correct refractive errors and presbyopia by reshaping the cornea.
Multiple sclerosis: A disease of the central nervous system wherein there is a loss of the outer covering of the nerve cells
Myasthenia gravis: A disorder involving the junction between nerves and muscles (neuromuscular junction) resulting in weakness of muscles