Refractive states of the eye Flashcards
The change in the curvature of the crystalline lens that helps to focus images of objects close to the eye
Accommodation
The relative ability of the refractive components of the eye to bring objects into focus on the retina
Refractive State
The refractive state of an eye that is able to focus correctly without the need for optical lenses
Emmetropia
The refractive state of an eye that is unable to focus correctly due to a refractive error
Ametropia
A nonpathological deficiency in the eye’s optical system
Refractive error
Also known as nearsightedness, ______, is a condition in which the cornea and lens of the non-accommodating eye have too much plus power for the length of the eye
Myopia
Also known as farsightedness, ______, is a condition in which the cornea and lens have too little plus power for the length of the non-accommodating eye
Hyperopia
Almost all infants are ______ at birth, but generally the eye lengthens and approaches “normal” size as the infant matures
Hyperopic
A cornea whose curvature is uniform
Spherical cornea
A cornea whose surface curvature is not uniform
Toric cornea
The refractive error of an eye whose corneal surface curvature is greater in one meridian than another; both distant and near objects appear blurred and distorted
Astigmatism
The meridians of maximum and minimum corneal curvature
Principal meridians
The most common form of astigmatism, in which the cornea resembles a football standing on one end or on its side
Regular astigmatism
The less common form of astigmatism, in which the corneal surface loses its uniformity secondary to scarring or other pathology
Irregular astigmatism
A progressive loss of the accommodative ability of the crystalline lens due to the natural process of aging is called
Presbyopia
