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What is keratoconus?

normal curvature of eye bulges outward

What is mechanism (cause) behind keratoconus?

smooth surface of cornea warps from ball shape to cone shape

What are the symptoms of keratoconus?

worsening vision, double vision, halo-like structures surrounding bright lights

What are the risk factors for keratoconus?

hereditary, rubbing eye causes it to occur more frequently, 

What are the treatments for keratoconus?

special contact lenses, cornea transplant, corneal crosslinking 

What is conjunctivitis?

inflammation of transparent membrane lining eye and eyelid

What is the mechanism (cause) of conjuctivitis?

blood vessels in conjunctiva become irritated and swollen

What are the symptoms behind conjuctivitis?

redness, itchiness, gritty feeling, 

What are the risk factors for conjuctivitis?

viruses, bacteria, allergies, foreign objects in eye

What are the treatments of conjunctivitis?

focus is on symptom relief, artificial tears

What is glaucoma?

group of eye conditions that damage optic nerve, usually due to pressure buildup 

What is the mechanism (cause) behind glaucoma?

high pressure in eyes damages optic nerve

depo provera

long acting progestin; injected into msucle every 11 weeks

What are the symptoms of glaucoma?

dependent on stage, include eye pain, blurry vision, eye redness

nuva ring

direct to blood stream through vagina and absorption

What are risk factors of glaucoma?

over age of 55, genetics, center of corneas is thin, eye injury

endometriosis

does not shed and goes up into abdomen

What are the treatments of glaucoma?

no cure, can be prevented with frequent eye screenings, eye drops, eye protection 

changes in ovary

mimicked by uterus changes

What is retinitis pigmentosa?

inherited eye disease that affects retina, causes issues with night vision, dim-light vision, and peripheral vision 

What is the mechanism (cause) behind retinitis pigmentosa?

caused by changes in certain genes that control/make up retina

What are the symptoms of retinitis pigmentosa?

problems with night vision, dim light, peripheral vision 

What are the risk factors of retinitis pigmentosa?

genetics

What are the treatments for retinitis pigmentosa?

low vision aids and assistive devices, sunglasses, gene therapy 

How many layers of the are there?

3 layers

Sclera - outermost

choroid - middle

retina - innermost 

What is the sclera made out of?

fibrous tunic 

What does the choroid (middle) layer do?

supplies blood to the eye

What is the choroid made out of?

vascular layer

What is the retina (innermost) layer do?

send impulses to optic nerve

What is the retina made out of?

photoreceptors (rods and cones)

What are the structures that make up the anterior portion of the eye?

cornea, zonular fibers, ciliary bodies, pupil, iris, lens

What is the function of the cornea?

transmits and refracts light

enters first as its transparent and is most exposed layer

What are the zonular fibers?

suspensory ligament that supports lens

What are the ciliary muscles?

support lens and determine thickness of lens

What are the ciliary bodies made of?

aqueous humor in anterior cavity

What does the pupil do?

admits and regulates the amount of light passed through to retina

What is the iris?

colored portion of eye

What are the four components that make up the posterior cavity of the eye?

vitreous humor, fovea centralis, optic disk, optic nerve

Does vitreous humor get replenished throughout life?

no, we are born with the amount of vitreous humor and it will not regenerate

Does aqueous humor get replenished?

yes

What is the fovea centralis?

site of highest visual acuity

high concentration of cones

found in middle of macula densa

What is the optic disc?

"blind spot" due to blood vessels entering/exiting

no photoreceptors

What is the optic nerve?

transmits electrical impulses from retina/eye to brain

T or F

The retina is not an extension of the brain.

F

Where are all photoreceptors located?

retina

What are the structural components of the retina?

macula lutea and fovea centralis

What is the macula lutea?

oval area surrounding fovea centralis

What is found in macula lutea?

rods and cones--\> there are no blood vessels in area

Where is the fovea centralis located?

center of macula lutea

What are rods?

light vs dark vision (more sensitive to light vision)

Where are rods most located?

periphery of retina

What are cones?

detail vs color

Where are cones most located?

fovea centralis

Pathway of neural vision?

light hits retina

passes to horizontal cells (lateral inhibition)

arrives at bipolar cells

amacrine cells

ganglion cells

stimulates optic nerve

optic chiasm

optic tract

lateral geniculate nucleus

optic radiations

visual cortex

Does lateral inhibition increase or decrease visual acuity?

increases visual acuity

Where does the temporal half of the retina project in the brain?

same side of the brain

Where does the medial/nasal half of the retina project in the brain?

crosses over to the opposite side of the brain

Where is the left visual field processed?

stimulates both eyes and is processed in right hemisphere of brain

women hormones

estrogen and progesterone

Where is the right visual field processed?

stimulates both eyes and is processed by left hemisphere of brain

changes in female hormones

regulate when ovulation occurs \~14 days after day 1 of bleeding

What happens to eyes in dim light?

radial muscles contract, circular muscles relax by sympathetic nervous system--\> dilates eyes

endometrium

stratum functionale (outermost) sheds during cycle

What happens to eyes in normal light?

radial and circular muscles contract by sympathetic nervous system

\--> average pupil size

egg pathway

ovary → oviduct → uterine tube → uterus (fertilization in uterine tube)

What happens to eyes in bright light?

radial muscles relax, circular muscles contract by parasympathetic reflex

\--> constricts pupils to decrease light coming in

speriogenesis

spermatids to spermatozoa

What is accommodation?

change in lens shape/thickness in order to see objects at different distances

spermatogenesis

creation of sperm

What is the accommodation for far vision (father than 20 feet)?

ciliary muscles relax, zonular fibers tighten--\> flat/thin lens

taking testosterone

stops feedback and reduces LH and FSH

What is the accommodation for close vision (less than 20 feet)?

ciliary muscle contract, zonular fibers relax

\--> fat/thick lens

male

epididymis to ductus (vas) deferens to seminal vesicle → ejaculatory duct (in prostate_ → urethra →bulbourethral gland → penis

What is emmetropia?

normal vision

eye focuses images correctly on retina

anterior pituitary

creates FSH and LH

What is myopia?

Nearsightedness, image focuses in front of retina, concave lenses to fix, eye is too big/long

hypothalamus

creates relasing hormone (GnRH)

What is hypertropia?

Farsightedness, image focuses behind retina, convex lenses to fix, eye is too small/short

regulate gonades

hypothalamus and anterior pituitary

What is astigmatism?

multiple focus points on retina, uneven lens to correct

other embryonic structures females

no testosterone so vagine, labia, and clitoris

What is the trichromatic theory of color?

human color vision due to 3 types of cones

S-cone is blue

M-cone is green

L-cone is red

other embryonic structures males

testosterone so prostate and penis/scrotum

What is the wavelength for blue?

380 - 550 nm

Mesoephric (wolffian) duct females

no testosterone so degenerates

What is the wavelength for green?

430 - 670 nm

Mesoephric (wolffian) duct males

testosterone leads to epididymides, ductus deferentia, and ejaculatory ducts

What is the wavelength for red?

500 - 760 nm

Paramesonephric (mullerian) duct female

no MIF so uterus and uterine tubes formed

Why can we see complex colors?

overlap from 3 cones

Paramesonephric (mullerian) duct males

MIf so degenerates

What causes color blindness?

lack of 1 or more cones

ovaries

no SPY gene or TDF; develop 3rd trimester

What does the Ishihara test measure?

color blindness, negative after images as well

Testes

have SRY gene on Y chromosome and TDF; develop early

What is the most common type of color blindness?

red and green

gametes

sperm or ovum

male

XY

female

XX

myometrium

contracts during labor