Chapter 17, Errors of Refraction

What is “astigmatism”?

a defective curvature of the cornea or lens of the eye

What is “hyperopia” (hypermetropia)?

farsightedness

What is “myopia”?

nearsightedness

What is “presbyopia”?

the impairment of vision as a result of old age

What is a “cataract”?

the clouding of the lens, causing decreased vision

What is the treatment for cataracts?

surgical removal of the lens with implantation of an artificial lens behind the iris

What is a “chalazion”?

a small, hard cystic mass (granuloma) on the eyelid

What is “diabetic retinopathy”?

a disease of the retina caused by diabetes mellitus

What is “macular edema”?

when fluid leaks from blood vessels into the retina and vision is blurred

What are “exudates”?

fluid leaking from the blood; appear in the retina as yellow-white spots

What is “glaucoma”?

increased intraocular pressure resulting in damage to the retina and optic nerve with loss of vision

How is glaucoma diagnosed?

by means of tonometry

What is acute glaucoma marked by?

extreme ocular pain, blurred vision, redness of the eye, and pupil dilation

What is trabeculoplasty?

laser therapy; improves aqueous humor outflow and reduces intraocular pressure

What is the preferred laser treatment for glaucoma?

SLT, selective laser trabeculoplasty

What is hordeolum (stye or sty)?

a localized, purulent, inflammatory staphylococcal infection of a sebaceous oil-producing gland in the eye

What is macular degeneration?

progressive damage to the macula of the retina; one of the leading causes of blindness in the elderly

What is dry macular degeneration marked by?

atrophy and degeneration of retinal cells and deposits of clumps of extracellular debris, or drusen

What is “nystagmus”?

the repetitive rhythmic movements of one or both eyes; can be found in newborns and may be congenital

What is “retinal detachment”?

when two layers of the retina separate from each other

What is “photopsia”?

bright flashes of light

What are “floaters”?

black spots or filmy shapes

What is a “macular hole”?

a small break in the macula (central section) of the retina

What is “pneumatic retinopexy”?

placement of an air bubble into the vitreous to hold the retina in place

What is “strabismus”?

an abnormal deviation of the eye; failure of the eyes to look in the same direction due to weakness of muscles

What are the different forms of “strabismus”?

1. esotropia (one eye turns inward, “cross-eyed”)

2. exotropia (one eye turns outward, “wall-eye”)

3. hypertropia (downward deviation of one eye)

What is “amblyopia”?

partial loss of vision from a “lazy eye”; can be reversed