Term
1) tunics
2) optical components
3) neural components |
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Definition
| 3 main components of the eyeball |
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Definition
| 3 layers that make up the wall of the eyeball |
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Term
| optical components of the eye |
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Definition
| the refractile media components which admit and focus light |
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Term
| the neural components of the eye |
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Definition
| consists of the retina and the optic nerve (retina is also part of the inner tunic) |
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Definition
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| cushions the eye during movement |
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Term
1)tunica fibrosa: sclera, cornea, conjunctiva
2)tunica vasculosa: choroid, iris, ciliar body, lens
3) tunica interna: retina and optic nerve |
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Definition
| name the 3 layers of the eye |
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Term
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Definition
| white part of the eye that covers most of the eye surface. made of dense CT with a rich blood/nerve supply, provides attachment site for external eye muscles |
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Definition
| modified part of the sclera that allows light to enter the eye |
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Definition
| forms a muscular ring round the lens, secretes aqueous humor, and supports the lens and iris |
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Term
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Definition
| a smooth muscle responsible for lens accomodation, contained within the ciliary body |
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Definition
| contraction of the ____ allows the lens to focus light onto the retina by changing its shape |
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Definition
| adjustable thin muscle controlling pupil diameter |
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Definition
| this structure block stray light from reaching the retina and contains a layer of cells called chromatophores which contain melanin |
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Term
| light reflecting off the epithelium of the posterior pigment |
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Definition
| high concentrations of melanin make the eye brown/black, what makes it blue, grey, or green? |
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Definition
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Definition
| the choroid provides oxygen and nourishment to the _____ layers of the retina |
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Definition
| what mammal has an avascular retina? |
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Term
| cornea - lens - vitreous humor - retina |
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Definition
| describe the path of light to the retina |
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Term
1) anterior chamber (space between cornea and iris)
2) posterior chamber (space between the iris and lens)
3) space between the lens and the retina |
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Definition
| name the 3 chambers of the eye (and their location |
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Term
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Definition
| consists of the cornea + the anterior and posterior chambers of the eye (so anterior to the lens) |
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Definition
| contains the vitreous chamber, the retina, retinal pigment epithelium, posterior sclera |
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Term
1) lacrimal apparatus
2) lacrimal gland
3) excretory lacrimal ducts
4) lacrimal puncta
5) lacrimal canals
6) nasolacrimal sac
7) nasolacrimal duct |
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Definition
| describe the path of tears from the lacrimal apparatus to the eye |
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Term
| water, salt, mucus, lysozyme |
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Definition
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Term
lipid from meibomian glands
aqueous later from lacrimal gland
mucin from conjunctival goblet cells |
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Definition
| what are the 3 layers of the precorneal film (tears) |
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Term
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Definition
| how many extrinsic eye muscle are there? |
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Term
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Definition
| muscles that originate in the orbit and insert on the sclera |
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Term
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Definition
| innervates the medial rectus to move eyes nasally |
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Term
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Definition
| innervates the lateral rectus to move eyes temporally |
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Term
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Definition
| innervates superior/inferior rectus to move the eye up/down |
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Definition
| innervates superior oblique to move the eye down/nasally |
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Definition
| innervates inferior oblique that moves eye up when eye is looking nasally |
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Definition
| condition in which the eyes are not properly aligned with each other due to a lack of coordination of the extraoccular muscles |
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Term
| depth perception (stereopsis) |
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Definition
| strabismus prevents proper binocular vision which can result in double vision (diplopia) which may adversely affect ____ |
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Definition
| energy carrying wave emitted by vibrating electrons |
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Definition
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Definition
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Definition
| the bending of light rays |
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Definition
| what refracts light in the eyes? |
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Term
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Definition
| ratio of speed of light in a vacccum compared to speed of light in the considered medium |
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Term
| index of refraction (IOR) |
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Definition
| velocity in air / velocity in medium OR wavelength in air/ wavelength in medium |
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Term
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Definition
| if wave speed slows down, what happens to wavelength? |
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Term
| the refractive index of the medium |
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Definition
| wavelength and velocity of light decrease in direction proportion to ____ |
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Term
| refractive power of a lens |
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Definition
| measurement of a lens expressed in terms of focal length or principal focal distance |
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Term
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Definition
| a lens with a focal length of 1 meter = 1 ___ |
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Definition
| a measure of how strongly a system converges (focuses) or diverges(defocuses) light |
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Definition
| a system with a greater focal length has a ___ optical power than one with a long focal length, thus it bends light more strongly bringing them into focus at a shorter distance |
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Definition
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Definition
| if focal length is 0.5 m, what is D? |
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Definition
| parallel rays of light form a far distance must be bent by ____ |
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Term
| air to aqueous humor change makes refraction of light on the surface of the cornea |
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Definition
| where does refraction occur in the eye, why? |
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Term
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Definition
| ___ depends on the curvature of the cornea |
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Term
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Definition
| reverse of focal distance (diopter) |
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Term
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Definition
| how many diopters does the cornea have? |
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Term
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Definition
| the amount of space viewed by the retina when the eye is fixated straight ahead |
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Term
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Definition
| ability to distinguish 2 nearby points |
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Term
1) spacing of the photoreceptors in the eye
2) the precision of the eye's refraction apparatus |
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Definition
| what does visual acuity depend on? |
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Term
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Definition
| distances across the retina described in degrees |
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Definition
| region of the eye where there are cones only, providing for great visual acuity |
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Definition
| chart used to measure visual acuity |
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Definition
| distance of the subject from the Snellen chart/ distance at which the letter can be read by a emmetropic or normal eye |
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Definition
| at what distance do you view the Snellen chart? |
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Definition
| how many lines are on a Snellen chart? |
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Definition
| changing of the shape of the lens to allow for extra focusing power (~12 diopters) |
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Term
| diverging (rather than parallel) |
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Definition
| focusing images within 9m ranges requires greater refraction for ___ rays |
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Term
| tensing of the zonule fibers decrease and ciliary muscle contraction causes the lens to become rounder and increase curvature |
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Definition
| how is accomodation achieved? |
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Term
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Definition
| what function is lost with age leading to presbyopia? |
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Term
1) increased curvature of the lens
2) constriction of the pupil
3) convergence of the eyes |
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Definition
| accommodation of near vision involves: |
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Term
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Definition
| minimal distance from the eye that an object can be clearly focused (~4in) |
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Term
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Definition
| blur is decreased by decreasing the refracted light in the eye by decreasing ___ |
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Term
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Definition
| is pupil constriction cholenergic or adrenergic? |
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Term
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Definition
| simultaneous inward movement of both eyes toward each other, usually in an effort to maintain singular binocular vision when viewing an object |
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Term
| close target causes a greater angle |
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Definition
| is the angle of convergence greater or smaller with a closer target (compared to a far target)? |
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Definition
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Definition
| positive/converging lenses are what shape? |
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Term
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Definition
| negative/diverging lenses are what shape? |
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Definition
| which type of lenses are more commonly used for glasses? biconcave or biconvex? |
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Term
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Definition
| a refractive defect due to the axial length of the eye or attributed defects in the refractive elements of the eye |
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Term
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Definition
| when an image is out of focus when looking distantly, but in focus when looking at a close object |
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Term
| converging lenses (negative power) which moves the focal point to the retina = concave lens |
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Definition
| whatkind of lens corrects myopia? |
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Term
| hyperopia (farsightedness) |
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Definition
| defect in vision caused by an imperfection in the eye (often when the eyeball is too short or the lens cannot become round enough |
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Term
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Definition
| this causes difficulty focusing on near objects and in extreme cases causes the sufferer to be unable to focus on objects at any distance |
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Term
| a convex lens that cause light to converge as it enters the eye (positive power) |
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Definition
| what fixes hyperopia? what kind of lens |
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Term
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Definition
| a decrease in the amplitude of accommodation as a consequence of aging |
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Term
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Definition
| a decrease in the amplitude of accommodation as a consequence of aging |
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Term
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Definition
| does not affect distance vision, but all eyes will become this way between 40 and 45 yrs |
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Term
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Definition
| results in either, or both blurred near vision and symptoms such as eyestrain and headaches. effects are more apparent at low light level |
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Term
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Definition
| occurs when parallel rays of light enter the eye (with accommodation relaxed) and do not come to a single point focus on or near the retina |
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Term
| the curvature of the cornea or lens |
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Definition
| horizontal and vertical light rays have different focal points due to ____ resulting in blurred vision |
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Term
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Definition
| if the lens curvature is messed up it is called |
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Term
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Definition
| if the cornea has an unequal curvature on its anterior surface it is called |
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Term
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Definition
| visual stimulation either fails to transmit or is poorly transmitted through the optic nerve to the brain for a continuous period of time |
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Term
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Definition
| this disorder often occurs in early childhood resulting in little or no vision in that eye |
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Term
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Definition
| a developmental problem in the brain (not an organic problem in the eye) |
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Term
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Definition
| in ambylopia, the part of the brain corresponding to the visual system of the affected eye is not stimulated properly and develops ___ |
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