Anatomy Flashcards
The refractive power of a crystalline lens is
17 diopter a
The refractive power of a cornia
43.00 diopter a
The space between the back of the cornea and iris is
Anterior chamber
The space between the iris and lens is
Posterior chamber
The largest space between the lens and retina is called
Vitreous chamber
The five layers of the cornea are in order
Epithelium, bowmans membrane, stroma, des meets membrane, endothelium
What part of the retina deals with day vision, details and color
Cones
What part of the cornea deals with night vision, peripheral vision and black and white
Rods
The largest part of the cornea is the
Stroma, 90%
The index of refraction of the cornea is
1.37
The index of refraction of the vitreous humor and the aqueous humor is
1.33 each
The index of refraction of the crystalline lens is
1.42
The outer protective coating of the eye that consists of the sclera and cornea is
Fibrous tunic
Consists of three parts…the iris, ciliary body and the choroid
Vascular tunic
What tunic consists of the retina
Neural tunic
What three things happen during accommodation
Ciliary muscle relaxes allowing crystalline lens to relax, eyes converge, pupils constrict
A constant tendency for the eyes to turn from the normal position for binocular vision is
Phoria.
A definite and obvious turning of the eye from the normal position for binocular vision is
Tropia
A tendency of the right eye to turn upward is
Right exophoria…. Exo is out
A definite turning inward of the left eye is
Left esotropia. Eso..in
A tendency of the right eye to turn upward is
Right hyper phobia…hyper is up
A definite turning downward of the left eye
Left hypotropia. Hypo is down
The extra ocular muscles are inserted into the sclera and serve to rotate the eye in all directions. There are how many muscles in each eye
6
Fusion occurs where?
In the brain
The ability of the eye to bring objects of varying distances to focus on the retina is called
Accommodation
When accommodation is at rest, rays of light from a distant source come into focus in front of the retina. This condition is known as
Myopia
When accommodation is at rest , rays of light from a distant source come into focus in front of the retina. This condition is known as
Hyperopia
The loss of vision without any apparent disease of the eye is
Amblyopia
Refractive error in the eye, when at rest, does not focus the image of an object upon the retina, includes hyperopia, myopia and astigmatism
Ametropia
A condition in which the ocular image of an object as seen be one eye differs so much in size or shoe from that seen by the other eye that the two images cannot be fused into a single impression
Aniskeikonia
A condition in which the refractive error of one eye significantly differs from that of the other, each eye must have the same sign
Anisometropia
A refractive condition whereby the signs in each eye are opposite, one eye is myopic and the other is hyperoptic
Antimetropia.
Absence of the crystalline lens
Aphakia
The clear watery fluid that fills the anterior and posterior chambers within the front of the eye
Aqueous humor
Refractive error that prevents the light rays from coming to a single focus on the retina because of various degrees of refraction in the various meridians of the eye
Astigmatism.
Condition where the crystalline lens becomes opaque with consequent loss of visual acuity
Cataract
The vascular inermedate coat that furnishes nourishment to other parts of the eyeball
Choroid
The refractive error which results in two points of focus falling behind the retina
Compound hyperoptic astigmatism
The refractive error which results in two points of focus falling in front of the retina
Compound nay optic astigmatism
The seeing of one object as two or double vision
Diplopia
The refractive condition of the normal eye at rest in which the image of distant objects is brought to a focus on the retina. No accommodation needed
Emmetropia
The small depression in the retina in the back of the eye, the part of the macula most adapted for acute vision
Fovea
The ocular disease of sustained intraocular pressure that the eye cannot withstand without damage to its structure or impairment of its function
Glaucoma
The refractive error, because the eyeball is short or the refractive power of the lens is weak, the point of focus for rays of light from distant objects falls behind the retina, accommodation to increase refractive power of the lens is necessary for distance as well as near
Hyperopia
The colored part of the eye that regulates the amount of light entering the eye by changing the size of the pupil
Iris
Refractive condition caused by a damaged cornea where the rays of light come to many focal points on the retina. Not correctable
Irregular astigmatism
Spectacle lenses designed to manipulate image size when dissimilar sizes make it difficult or impossible for fusion to occur, such as in aniseikonia
Iseikonic lenses
The small area of the retina that surrounds the fovea and with the fovea comprises the area of the retina that gives distinct vision
Macula
The refractive condition in which light comes to two points of focus where one is in front of the retina and the other is behind the retina
Mixed astigmatism
A refractive error in which the eyeball is too long in relation to its focusing power, thus the point of focus falls in front of the retina
Myopia
The special nerve of the sense of sight that carries impulses from the retina got the brain
Optic nerve
The gradual lessening of the power of accommodation due to a physiological change that becomes noticeably apparent about the age of 40
Presbyopia
A small spring wire attached nasally to a spectacle frame to lift a drooping lid
Ptosis crutch
Condition in which rays of light come to two focal points and is correctable
Regular astigmatism
The white part of the eye. Tough covering which, with the cornea, forms the external protective coating of the ye
Sclera
The transparent colorless mass of soft, gelatinous material filling the eyeball behind the lens
Vitreous humor
Failure of the two eyes to simultaneously direct their gaze at the same object because of muscle imbalance. Also known as squint
Strabismus
Refractive condition where one point of focus falls on the retina and the other falls behind the retina
Simple hyperoptic astigmatism
The refractive condition where one point of light falls on retina and the other falls in front of the retina
Simple myopic astigmatism
The average person blinks how many times per minute
7 to12
