Refractive States Flashcards
Emmetropic
Normal eye , 20/20 vision, no refractive errors
Hyperopia
Far sighted [near is blurry] corrected w/ plus lens
Types of hyperopia
Latent hyperopia - corrected by eyes own accommodations
Manifest hyperopia- can be corrected by convex lens or patients’ own accommodations
Myopia
Myopic/near sided vision [can’t see far] - corrected w/ minus lens
Types of myopia
Axial myopia- parallel rays of light brought to converging point in the vitreous in front of retina
Curvature myopia - eye is normal sized but lens and cornea are more curved
Index myopia - change in index of refraction of the lens [dm or cataract]
Astigmatism
Ray of light isn’t refracted equally in all directions - corrected w cylinder lenses and axis
Types of astigmatisms
Simple - Light rays are focused in one meridian - either front of retina or behind
Compound - Light rays are focused in both meridians- infront or behind retina
Mixed - focal point lies both behind and infront of retina
Presbyopia
Aging process of eye
Refractive conditions corrected w/
Glasses
Contact lenses
Lasik
PRK [scapels instead of lasers]
Refractometry
Measurement of refractive error
[Not to b confused w refraction]
Refraction
Decides what lenses will most benefit the PT if needed
Methods of refractometry
Obj- retrieves measurements w/o PT needing to give answers
Sub- PT participates to give best judgments for measurements
Anisometropia
Difference in the refractive error of the two eyes
[Causes include - lazy eye & cross eyed]
Aniseikonia
Diff in size of the retinal image - affects PT spacial judgments
Aphakia
Crystalline lens is absent from eye
Pseudophakia
False lens -implant of an intraocular lens to replace natural lens
- cataract surgery
Jack in box phenomenon [aphakia related]
an object is seen with peripheral vision, the eye turns to look directly at the object and the object disappears.
Cilicia
Lashes
