Eyes

What are the causes of cataracts?

1. Age-related 2. Congenital from Rubella, Wilson's Disease, or Galactosemia 3. DM 1 in which there is a bilateral "snowflake" cateract. 4. Glaucoma and Uveitis 5. Chemicals (steroids, dinitrophenol) 7. Heat, trauma, radiation

What is the normal intraocular pressure measurement?

15 mmHg

How are the vision deficits from astigmatism corrected?

2 cylindrical lenses of different strengths at right angles

Match the cells/ parts to the layers of the retina that they occupy. __Contains cell bodies of Rods and Cones __Where synapses to Ganglion cells occur. __Contains cell bodies of Bipolar and Amacrine cells. __Where Rods and Cones synapse on Horizontal cells. __Contains melanin and stores Vitamin A 1.Pigmented Layer 2.Outer Nuclear Layer 3.Outer Plexiform Layer 4.Inner Nuclear Layer 5.Inner Plexiform Layer

2,5,4,3,1

Glaucoma can be diagnosed with an intraocular pressure over ______.

25 mmHg

Match the vision term with it's description. _Refractive error of plane-dependent focal length. (Egg shaped cornea) __Corrected with a convex lens. __Failure of lens accommodation. __Physiologic Normal 20/20 vision __Light rays focus in front of the retina. 1.Myopia 2.Hyperopia 3.Presbyopia 4.Emmetropia 5.Astigmatism

5,2,3,4,1

What is the total refractive power of the "reduced" eye?

59 diopters and the cornea is 2/3 of refractive power

Opacification of the lens of an aged person that causes loss of vision at night and increased glare is most likely due to _______. Question options: Open angle glaucoma Congenital cataract Keratoconus Closed angle glaucoma Age related cataract Presbyopia

Age related cataract

What is Vitamin A? Question options: Metarhodopsin II Transducin 11-cis retinal All-trans retinol Rhodopsin kinase

All-trans retinol

Which is FALSE concerning refractive lenses and focal points? A. A higher refractive power lens will have a shorter focal length than a lens with a lower refractive power. B. Light rays entering a convex lens will diverge C. A cylindrical convex lens bends light to form a focal line. D. Light rays from a near source will have a longer focal length than those from a far light source.

B. Light rays entering a convex lens will diverge

Light traveling at shorter wavelengths (near 450 nm) will maximally stimulate cones of that spectrum and will give the perception of ________. Question options: Black Green White Red Blue

BLue

Inner nuclear layer

Cell bodies of bipolar, horizontal, and amacrine cells

Place in order the flow of aqueous humor from production to drainage. __Iridocorneal angle __Posterior chamber _Canal of Schlemm __Pupil __Anterior chamber __Ciliary processes

Ciliary processes, posterior chamber, pupil, anterior chamber, iridocorneal angle, canal schlemm

Which takes about 10 minutes to adjust or respond to a decrease in light intensity (increased darkness)? Question options: Constriction of the pupil Cone adaptation Dilation of the pupil Rod adaptation Neural adaptation

Cone adaptation

Which is FALSE concerning Rods and Cones Cones use photopsin in color pigments of yellow, red, and blue. Rods have a higher dark adaptation ability than cones. Receptor potentials in cones are 4 times faster than in rods. Rods use rhodopsin transmembrane proteins stored in outer segments. The fovea centralis has the highest concentration of cones.

Cones use photopsin in color pigments of yellow, red, and blue.

Which provides the most rapid accommodation to an increase in light intensity? Question options: Neural adaptation Cone adaptation Constriction of the pupil Rod adaptation Dilation of the pupil

Constriction of the pupil

Place the structures in the order that light entering the eye pass through. _Vitreous Chamber __Lens __Retina __Cornea __Pupil __Anterior Chamber

Cornea, Anterior chamber, pupil, lens, vitreous humor, retina

Failure of aqueous humor to drain due to the clogging of the trabecula with debris causes an increase in intraocular pressure and loss of peripheral vision called ______. A. Presbyopia B. Congenital cataract C. Keratoconus D. Open angle glaucoma E. Age related cataract F. Closed angle glaucoma

D. Open angle glaucoma

What is the product of the decomposition of rhodopsin when exposed to light? Also known as "Activated Rhodopsin". Metarhodopsin II 11-cis retinal All-trans retinol Transducin Rhodopsin kinase

Metarhodopsin II

Which is a mechanism of depth perception used when the visual cortex interprets objects moving faster through the visual field as being closer? Question options: Moving parallax Bitemporal hemianopia Size of known objects Stereopsis

Moving parallax

Light traveling at longer wavelengths (600+ nm) will maximally stimulate cones of that spectrum and will give the perception of ________. Black Red Blue White Green

Red

Place in order the sequence of the visual pathway from the eye to the cerebral cortex. ___Optic Chiasm __Optic Radiations __Optic Nerve __Optic Tract __Retina __Lateral Geniculate Nucleus of the Thalamus

Retina, optic nerve, optic chiasm, optic tract, lateral geniculate nucleus of thalamus, optic radiations

How is Rhodopsin formed?

Rhodopsin decomposes to metarhodopsin II metarhodopsin II converts to scotopsin ( can be recycled) or all trans-retinal all trans-retinal to 11 cis retinal by isomerase 11 cis retinal + scotopsin= rhodopsin

Keratoconus

abnormally shaped or bulging cornea cornea looses integrity and bulges out idiopathic

What are the symptoms of cataracts

age related= loss of vision, especially at night, glare

What does Metarhodopsin II split into?

all trans retinal scotopsin

How does the diameter of the pupil affect the depth of focus?

as the pupil diameter decreases the depth of focus increases because the 2 points of light are in better focus on the retina

When exposed to light, what does Rhodopsin decompose to

bathorhodopsin

inner plexiform layer

bipolar, amacrine, ganglion synaptic contacts

Rods are for

black and white and night vision

What visual deficits are caused by glaucoma? Why?

blindness because the pressure builds up and blocks the lens

What changes are seen in the optic disc with glaucoma?

bulk loss of axons of optic disc will cause the optic disc to decrease and the optic cup to enlarge increase cup to disc ratio

How is aqueous humor reabsorbed into the venous system?

canal of schlemm

contents/function of outer nuclear layer

cells bodies of rods and cones

What supplies the inner components/surface of the retina

central retinal artery

The outermost layer (Pigmented layer and outer segments of Rods and Cones are supplied by the _____________

choroid

What structure makes aqueous humor?

ciliary body

Describe the structures that Aqueous humor travels through in the eye

ciliary body to posterior chamber to pupil to anterior chamber to iridocorneal angle to trabeculae to canal of schlemm to small veins to extraocular veins

Cataract

clouding of the lens of the eye can be congenital or from old age

Cones are for

color vision

bipolar cell function

conduction vision info

Which neural pathway mediates the motor control of accommodation? Name all the players.

controlled by parasympathetic nerves the edinger-westpal nucleus of brainstem to the ciliary ganglion to the short ciliary to ciliary muscles

Function of rods and cones

convert light energy into electrical signal

What structure of the eye provides the greatest refractive power?

cornea

Name the 4 refractive interfaces of the eye. Which provides the greatest refractive power?

cornea= most, aqueous humor, lens, vitreous humor

Which type of lens is used to correct Hyperopia? Myopia?

correct myopia with concave lens correct hyperopia with convex lens

ganglion cell function

depolarize form optic nerve

What is retinal detachment?

detachment of the retina

what is +1 diopter

farsighted; focus rays from farther distance

hyperopia

farsightedness; focal point beyond retina

The axons of which neurons form the optic nerve?

ganglion cells

Function of the pigment layer

has melanin to prevent light refraction stores vitamin A

presbyopia

impaired vision as a result of aging loss of lens accommodation loose pliability of lens

What is the Fovea centralis? Where is it located? What type of cells are found in it

in center of retina all cones for acute vision

Glaucoma

increased intraocular pressure from increased production of aqueous humor and decreased drainage open or closed progressive loss of peripheral fields

How does contraction of the ciliary muscles cause increased bending of the lens?

it relieves the pressure on the suspensory ligaments which allow the lens to bend

function of horizontal cells

lateral inhibition to increase visual acuity

What structure of the eye is able to change refractive power to accommodate near and far vision?

lens

A _______ is formed as light travels through a cylindrical lens

line of focus

How is intraocular pressure usually measured?

measured in mmHg by tonometer

What is the final, active form from the degradation of Rhodopsin?

metarhodospin II

amacrine cell function

modify visual output

ganglion cell layer

multipolar cell bodies of ganglion cells= depolarize

layer of optic nerve fibers

myelinated axons of ganglion cells form optic nerve, exit via optic disc

what is -1 diopter? what type of lens gives negative diopters

nearsighted; concave lenses

myopia

nearsightedness; focal point in front of retina

Define emmetropia

normal vision

What is the most common type of glaucoma?

open angle glaucoma

What is the difference between open angle glaucoma and closed angle glaucoma?

open angle is when clogging of trabecular occurs by debris, no gross structural abnormalities closed angle= iris adheres to trabecular meshwork and physically impeded the flow of aqueous humor out of eye

The central retinal artery is a branch of

ophthalmic artery

What are the components of rods and cones

outer segment=membrane lined with rhodopsin/ color pigment inner segment= mitochondria, RER nucleus= DNA synaptic body= release neurotransmitters

Contents/function of layer of rods and cones

outer segments and inner segments of photoreceptors

What makes up/function the pigmented layer

outer segments of photoreceptors stores vitamin A, limits reflection

rods have rhodopsin. cones have ______

photopsin

Place in order the layers of the retinal cells from external (posterior) to internal (anterior). ___Receptor layer (rods and cones) __Horizontal cell layer __Amacrine cell layer __Ganglion cell layer __Bipolar cell layer __Pigment layer

pigment layer, receptor layer, horizontal layer, bipolar cell, amacrine layer, ganglion cell layer

What are the layers of the retina

pigmented layer, layer of rods and cones, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion layer, layer of optic nerve, inner limiting membrane

What is the order of structures that light passes through as it enters the eye to stimulate the retina

pigmented layer= absorb and scatter light photoreceptors= rods and cones outer plexiform layer= synapse for rods and cones interneurons= horizontal cell=lateral inhibition, bipolar cells- main conduction , amacrine cells-modify output inner plexiform layer= synapse ganglion cells= form optic nerve

A ________ is formed as light travels through a spherical lens

point of focus

As one ages, the lens becomes stiffer and loses the ability to accommodate near vision. This is called __________.

presbyopia

What happens to the scotopsin?

recycled

bending of light an an angulated surface is called______

refraction

astigmatism

refractive error where the visual image in 1 plane focuses at different distance from that of the place at a right angle to it axis of focus for each plane

A lens that bends light to a nearer focal point has more _____, which is measured in _____

refractive power; diopters

What are the causes of congenital cataracts? When are congenital cataracts surgically treated?

rubella, glucosemia, diabetes mellitus, Wilson's disease, atopic dermatitis when 6-8 weeks old, once get diagnosis

inner limiting membrane

separates the retina from the vitreous body.

A +2 diopter would focus light at

shorter focal lengths

What are the 3 mechanisms used by the eye and brain to detect how near or far away an object is? (Depth perception)

size of a known object= larger means closer stereopsis= father apart hit retina at closer points moving parallax= object close move faster

Content/function of outer plexiform layer

synapse sites for rods and cones to horizontal cells and bipolar cells

Describe the mechanism of Accommodation.

the ciliary muscles contract and relieve the tension of the suspensory ligaments, allowing the lens to bend lens bends more as more pressure from the suspensory ligaments is relieved

what is the definition of of focal length of a lens? why is it important to note that the entering light is parallel

the distance beyond a convex spherical lens at which the parallel rays converge to a focal point the lens causes the light to bend, the light isn't bent beforehand

if light rays are coming from nearby source, they are diverging as they enter the lens. How will this change the focal length (focal distance/point)

the focal length will be greater

what happens to light rays as they pass through an angled interface

the light rays are bent

what happens to light rays traveling through convex lens

the light rays are focused to a focal point and the focal length shortens

What happens to light rays when they enter a transparent substance interface perpendicular to the beam of light

the light rays are shortened

what happens to light rays traveling through a concave lens

the light rays diverge and the focal length is longer

What are pigments

transmembrane proteins of the discs incorporated into the membrane of outer membrane of rods and cones

What are secondary causes of glaucoma

trauma inflammation pigment granules necrotic tumors pseudo exfoliation= deposit of fibrinous material

what is the orientation of the image formed on the retina

upside down and reversed

what is the orientation of an image formed by a convex spherical lens

upside down and reversed left to right

when would an axis of a lens need to be identified in addition to the diopter

when comparing 2 cylindrical lenses