Vision Assessment in Infants and Conditions

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Questions and Answers

What was the first indication that Molly might have vision problems?

Molly would often focus her gaze on lights and rub her eyes frequently.

Why would a Snellen eye chart be difficult to administer to an infant?

The Snellen eye chart requires the individual to read letters or numbers, which an infant cannot do.

How should a typical pupil react to bright light?

A typical pupil should constrict in bright light.

Besides the tests mentioned, what other methods could be used to test a baby’s vision?

Other methods could include observing the infant's ability to fixate on objects, or using a visual evoked potential test (VEP). Signup and view all the answers

What genetic condition was Molly diagnosed with, and what gene was involved?

Molly was diagnosed with Leber Congenital Amaurosis (LCA) involving the RPE65 gene. Signup and view all the answers

What is the chance that two parents who carry one defective copy of the gene for Leber Congenital Amaurosis (LCA) would have a child with LCA?

There is a 25% chance. Signup and view all the answers

What is the primary function of the eyelid?

To cover and protect the eye. Signup and view all the answers

What is the function of eyelashes besides protecting from dust?

Eyelashes help protect the eyes from debris. Signup and view all the answers

What is the medical term for pink eye?

conjunctivitis Signup and view all the answers

What is the function of the lacrimal glands?

to produce tears Signup and view all the answers

Besides moistening the eye, what other function do tears serve?

tears have enzymes that kill bacteria Signup and view all the answers

What is the transparent dome of the eye that focuses light?

cornea Signup and view all the answers

What is the condition in which the cornea thins and develops a cone-like bulge?

keratoconus Signup and view all the answers

Which part of the eye is the 'white of the eye'?

sclera Signup and view all the answers

What is the 'cooperative eye hypothesis'?

the human eye's distinctive visible characteristics evolved to make it easier for humans to follow another's gaze while communicating. Signup and view all the answers

What exits at the optic disk and transmits information from the eye to the brain?

optic nerve Signup and view all the answers

What is the name of the structure in the eye that contains blood vessels?

Choroid Signup and view all the answers

What is the function of the ciliary body?

Holds the lens in place Signup and view all the answers

What role does melanin play in determining eye color?

Adds color to the eyes Signup and view all the answers

What is the name for the condition where one eye is a different color than the other?

Heterochromia Signup and view all the answers

What causes 'red-eye' in photographs?

Reflection of the flash off the retina's blood vessels Signup and view all the answers

What part of the eye are photoreceptor cells located?

Retina Signup and view all the answers

What are the two types of photoreceptors, and what type of vision is associated with each?

Rods are for monochromatic (b&w) vision, cones are for color vision. Signup and view all the answers

Why do rainbows occur after it rains?

Light passing through water droplets separates into the colors of the spectrum. Signup and view all the answers

What are the two primary colors that dogs can perceive?

Dogs can only perceive yellow and blue. Signup and view all the answers

What is the effect of the lens shape changing during accommodation?

The lens changes shape to facilitate focusing on objects. Signup and view all the answers

What is the condition known as cataracts, and how is it treated?

Cataracts involve the clouding of the lens and are treated by replacing it with an intraocular lens (IOL). Signup and view all the answers

How do the iris and pupil function in regulating light?

The iris constricts or dilates to regulate the amount of light entering through the pupil. Signup and view all the answers

What is aniridia?

Aniridia is a condition where a person is born without an iris. Signup and view all the answers

What symptoms are associated with retinal detachment?

Symptoms include flashing lights, new floaters, and a shadow in the peripheral vision. Signup and view all the answers

What genetic factor contributes to color blindness, particularly in boys?

Color blindness is linked to a gene located on the X chromosome. Signup and view all the answers

What role do the Zonules of Zinn play in eye function?

The Zonules of Zinn connect the ciliary body to the lens and control its shape. Signup and view all the answers

Study Notes

Chapter 14 - Sensory Perception (EYE)

Molly's mother noticed vision problems when Molly was a baby.
While breastfeeding, Molly focused on room lights, frequently rubbing and pressing her eyes.
Molly was tested by a doctor, undergoing a series of vision tests.
Molly did not react to bright light during the vision tests.
Molly's pupils reacted slowly to bright light.
Molly could not track moving objects.
Molly frequently bumped into objects and tripped over things.
Additional tests, including a genetic test, were ordered to identify potential hereditary blindness.
Molly was diagnosed with Leber Congenital Amaurosis (LCE).
Molly inherited two defective copies of the RPE65 gene. Each parent had one defective copy (recessive).

Eye Structure and Functions

Eyelids: Cover and protect the eye; thin skin.
Eyelashes: Fine hairs protecting eyes from dust and debris.
Trichiasis: Inversion of eyelashes, irritating the eye.
Conjunctiva: Covering around the eye and under eyelids.
Pink Eye (Conjunctivitis): Inflammation of the conjunctiva (bacterial, contagious).
Extrinsic Eye Muscles: Move the eye (superior rectus, lateral rectus, superior oblique, medial rectus, inferior oblique, inferior rectus).
Lacrimal Glands: Produce tears that drain into nasal cavity via lacrimal duct.
Tears: Moistens and lubricates the eye surface, containing enzymes killing bacteria.
Canaliculi: Drain tears; part of the tear drainage system.
Cornea: Transparent dome focusing light.
Cornea Transplants: Possible replacement for damaged or diseased corneas.
Keratoconus: Eye condition where cornea thins and bulges (cone-like shape).
Sclera: Continuation of the cornea, the white of the eye.
Cooperative Eye Hypothesis: Human eye's appearance evolved for easier following of another's gaze, facilitated communication.
Optic Nerve: Exits at the optic disk, transmitting information to the occipital lobe of the brain.
Optic Disk (Blind Spot): Area lacking photoreceptors.
Choroid: Contains blood vessels.
Ciliary Body: Holds lens, assists in focusing.
Lens: Focusing light; reverses image (objects are upside-down).
Pupil: Opening allowing light into the eye.
Iris: Colored portion of eye, regulating pupil size.
Aqueous Humor: Liquid surrounding the lens.
Vitreous Humor: Supports internal parts of the eye; fluid within the eye.
Retina: Visual receptor cells.
Fovea Centralis/Macula: Region with sharpest vision.
Photoreceptors (rods and cones): Rods for monochromatic vision (black and white), Cones for color vision.
RPE65: Protein expressed in photoreceptor cells; mutated form causing cell death in LCA.
Methanol Poisoning: During Prohibition, a significant cause of blindness due to chemicals in wood alcohol.
Red-Eye: Caused by flash reflection off retina blood vessels.
Blind Spot (Optic Disk): No photoreceptor cells present at the point where optic nerve exits the eye.

Problems with the EYE

Cataracts: Clouding of the lens leading to a clinical condition.
Treatment (Cataracts): Lens removal and artificial intraocular lens (IOL) replacement.
Aniridia: Condition of being born without an iris.
Onchocerciasis (River Blindness): Disease caused by infection with a parasitic worm, resulting in severe symptoms like itching and blindness.
Color Blindness: Genetic trait affecting boys more, located on the X chromosome
Floaters: Vitreous substance clumps, casting shadows on the retina.
Retinal Detachment: Retina pulled away from its normal position.
Glaucoma: High pressure from vitreous humor damages optic nerve (can lead to blindness).
Hyperopia (Farsightedness): Light focuses behind the retina; requires corrective plus lenses.
Myopia (Nearsightedness): Light focuses in front of the retina; requires corrective minus lenses.
Astigmatism: Cornea irregularity making some parts of the field of view out of focus.

Treatment Options

Glasses or contact lenses: Common vision correction for many eye problems.
LASIK surgery: Corrective eye surgery involving creating a flap in the cornea to reshape it.
Gene therapy: Possible treatment option for some forms of blindness.

###Additional Notes

The image of the Mona Lisa upside down is used to illustrate the brain difficulties interpreting upside down images.
Various diagrams and images illustrate these concepts.
There is mention of a 2010 FDA approval for a gene therapy for certain forms of blindness.

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Description

This quiz focuses on vision assessment techniques in infants, including how to interpret signs of vision problems and the use of various diagnostic tools. Additionally, it covers genetic conditions affecting vision such as Leber Congenital Amaurosis. Test your knowledge on the anatomy of the eye and its functions.