Presbyopia is part of the normal process of aging. As a person becomes older, one begins to lose the flexibility of the lens of the eye which limits the ability of the eye to change its point of focus from distance to near. Pupil is what appears as a small black dot in the center of the iris and changes its diameter in response to ambient lighting. Refractive Errors are hyperopia, myopia, astigmatism and presbyopia. Retina is the part of the eye that lines the inside wall of the eye and consists of fine sensory tissue which acts as the film in a camera that captures and transmits images.
Stroma is the thick, middle layer of cells in the cornea.
Undercorrection is a complication of refractive surgery where the expected amount of correction is less than desired and often occurs where healing regresses more vigorously than predicted. Visual Acuity is simply the clearness of vision or the ability to distinguish details and shapes or objects. Vitreous Humor is the transparent, colorless mass of gel that lies behind the lens and in front of the retina and fills the center of the eyeball.