COA exam study (JCAHPO)
A-scan - ANS-An ultrasound technique to determine the axial length of the eye to
calculate the intraocular lens power required.
Abbe number - ANS-An indication of optical quality. Number is inversely proportional to
the chromic dispersion of a specific lens material
Abcess - ANS-Localized area of inflammation
Abduct - ANS-to turn away from the midline
Abductor - ANS-A muscle that rotates the eye away from the midline (e.g. lateral rectus)
Aberrant - ANS-Turning away from the midline
Ablation - ANS-The removal of tissue as occurs with the excimer laser on the cornea for
refractive changes.
Abrasion - ANS-Rubbing off of the superficial layer
AC/A - ANS-Accommodative convergence/accommodation ration; expressed as the
ratio between convergence caused by accommodation (in prism diopters) and
accommodation (in diopters).
Accommodation - ANS-Adjustment by the eye for seeing at different distances,
accomplished by changing the shape of the crystalline lens through the action of the
ciliary muscle.
Achloropsia - ANS-Color blindness to green
Achromatic lens - ANS-A lens that neutralizes dispersion without interfering with
refraction.
Acuity - ANS-Clearness; visual acuity is measured by the smallest object that can be
seen at a certain distance.
Add - ANS-The total dioptric power added to a distance prescription to supplement
accommodation for reading.
A-scan - ANS-An ultrasound technique to determine the axial length of the eye to
calculate the intraocular lens power required.
Abbe number - ANS-An indication of optical quality. Number is inversely proportional to
the chromic dispersion of a specific lens material
Abcess - ANS-Localized area of inflammation
Abduct - ANS-to turn away from the midline
Abductor - ANS-A muscle that rotates the eye away from the midline (e.g. lateral rectus)
Aberrant - ANS-Turning away from the midline
Ablation - ANS-The removal of tissue as occurs with the excimer laser on the cornea for
refractive changes.
Abrasion - ANS-Rubbing off of the superficial layer
AC/A - ANS-Accommodative convergence/accommodation ration; expressed as the
ratio between convergence caused by accommodation (in prism diopters) and
accommodation (in diopters).
Accommodation - ANS-Adjustment by the eye for seeing at different distances,
accomplished by changing the shape of the crystalline lens through the action of the
ciliary muscle.
Achloropsia - ANS-Color blindness to green
Achromatic lens - ANS-A lens that neutralizes dispersion without interfering with
refraction.
Acuity - ANS-Clearness; visual acuity is measured by the smallest object that can be
seen at a certain distance.
Add - ANS-The total dioptric power added to a distance prescription to supplement
accommodation for reading.
