Phase 1 Flashcards
(33 cards)
Sclera
White part of eye, thick, tough, protective layer covering entire eyeball. Extraocular muscles attach to accelerate to allow movement of eye.
Conjunctiva
Clear thin membrane of tissue covering front of the eye. It’s divided into the palpebral conjunctiva (lines back side of eyelids) & bulbar conjunctiva (overlies the sclera).
Cornea
Clear layer of tissue at front of eye. The cornea, tear, & lens refract light so the eye can focus. The cornea is transparent & does not have blood vessels; needs oxygen directly from the air. Astigmatism, near & farsightedness can be caused if the shape is not as it should be.
Iris
Colored part of the eye. Color depends how much melanin (pigment) they contain. The iris controls diameter & size of pupil & amount of light that reaches the retina.
Ciliary Body
Responsible for producing aqueous humor (fluid for maintaining intraocular pressure & providing nutrients/antioxidants to eye).
Anterior Chamber
Space between the cornea & iris filled w/ aqueous humor. The Aqueous fluid drains out of the eye at the angle (where the iris meets the cornea) through the trabecular meshwork. Then drains into the superficial veins of the eye.
Pupil
An opening in the iris & appears as a black, round circle in middle of eye. Pupil acts as the eye’s aperture, allowing more/less light into eye.
Lens
Transparent part of eye that refracts light so it’s focused on the retina. Lens normally changes shape allowing eye to focus on objects at different distances. The lens becomes thicker w/ age & can not change shape so easily, which is why as we age it may be more difficult to focus on close small objects w/o reading glasses.
Vitreous Humor
Clear gel that fills most of the inside of eyeball. Get ensures the eyeball holds it’s spherical shape & maintains the pressure of eye. The vitreous is firmly attached to the retina & optic nerve when we are younger. With age, vitreous condensed down & plugs off retina (posterior vitreous detachment, PVD).
Retina
Retina lines the inner surface of the back of eye. Millions of photoreceptors, called rods & cones, in the retina which capture rays of light. Light falls on the retina, photoreceptors turn them into electrical impulses that trigger nerves & are sent to visual areas of the brain through the optic nerve.
Macula
Oval, highly pigmented spot near centre of the retina at back of eye & is responsible for central vision. Macula is yellow & absorbs excess blue & ultraviolet light that enters eye. Macula contains a high density of cones & is needed for both accurate central vision & color perception.
Optic Nerve
Is a collection of communication wires which convey info from the retina in the eye to brain. Our “blind spot” is due to a lack of retina where optic nerve leaves the eye.
Choroid
Layer of blood vessels & connective tissue between sclera & retina. Choroid provides oxygen & nutrients to the retina. Macula & optic nerve are dependent upon blood supply from the choroid.
Refractive Error
Light is not being focused on the fovea correctly! Nearsightedness (myopia - ) means light is focused in front of fovea. Farsightedness (hyperopia + ) means light is focused behind fovea. Astigmatism means light is focused differently in Two meridians. Refractive error can be fixed w/ glasses, ctls, refractive sx, or lens implants in cataract sx.
Glaucoma
High pressure in eye which damages optic nerve leading to permanent vision loss. Vision loss begins in periphery & progresses centrally w/ time.
Cataract
Cloudiness of lens causing gradually progressive blurry vision. Usually age related, can also be due to diabetes, steroid use, traumas & other factors. Sx removal & Replaced w/intraocular lens.
Age Related Macular Degeneration (ARMD)
Eye disorder associated w/ aging resulting in damage to the macula & central vision. Two forms: Wet ARMD & Dry ARMD.
Wet ARMD
Is when abnormal blood vessels from the choroid break through into the retina & cause bleeding & leakage of fluid. Leads to scarring & permanent damage which can lead to rapid central vision loss. An early symptom of wet ARMD is that straight lines appear wavy. Injections into eye treat the disease.
Dry ARMD
When the macula thins overtime as part of the aging process, gradually blurring central vision. Drusen is a early sign.
Diabetic Retinopathy
Abormalities of the small blood vessels in retina which can lead to blessing/swelling of retina. May require laser treatment/injections into eye. May be asymptotic or have blurry vision/floaters.
Epiretinal Membrane (ERM)
Abnormal thickening of most superficial layers of retina. EEN & the traction on the retina it can sometimes cause/affect clarity of vision.
Posterior Vitreous detachment (PVD)
Occurs as the vitreous gel condenses down & pulls off of the nerve & retina. May have symptoms of floaters/flashes. Can cause retinal tear/detachment.
Retinal Detachment (RD)
Separation of the retina’s attachment to choroid. Early detection is important & sx is almost always necessary.
Symptoms: floaters flickers/flashes of light.
Conjunctivitis
Inflammation of the conjunctiva leading to redness/mucoid discharge; can have many cases including chemical, viral, bacterial & allergic.
