- How does diabetes causes blindness? Is it reversible?
- What spinal reflexes can a person have after death? How is this possible? When do these reflexes stop working?
- Do people with lighter colored eyes have more red-eye in pictures?
- What is astigmatism? How do treatments for it work?
- How do the scuba masks with pink lenses work to make you see more colors?
- What limits the frequencies of sound that people can hear? How is this different than other animals? How does the structure of the ear differ among types of animals?
- Can you improve your reflexes?
- Are Q-tips bad to use in your ears? Why?
- Can cats really see in the dark? How? How are cats’ eyes different than peoples eyes?
- Does uv light (from the sun or a tanning bed) damage the eye?
Saturday, June 6, 2009
Lab 3 Quiz Bank Questions
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Anna Pryyma
ReplyDeleteWhat is Astigmatism? How do treatment for it work?
Astigmatism is a condition that causes blurry vision in individuals whose cornea is misshapen. Normally cornea has a round shape. However, when it’s shape resembles that of an oval, there is more than one curve on the cornea. This causes the light to reflect in more than one place, thus causing blurriness. There is no cure for astigmatism, however the condition can be corrected by laser surgery. When lasik procedure is performed (non-invasive), the cornea is reshaped to normal with the help of the lasers. Another way to reshape the cornea is to wear a specially designed, rigid set of contact lenses. Wearing these lenses will gradually reshape the cornea. This procedure is called orthokeratology.
American Optometric Association. (2009). Astigmatism. Retrieved June 6, 2009, from http://www.aoa.org/Astigmatism.xml
Anna Pryyma
ReplyDeleteAre Q-tips bad to use in your ears? Why?
Using cotton swabs to clean your ears can potentially cause irreversible damage. Cotton swabs can damage the lining of the ear canal and start an infection. They usually push the ear wax deeper into the ear canal, thus causing blockage. Q-tips can also damage the eardrum and cause permanent hearing loss. Doctors usually advise against using q-tips to clean out the wax from the ears.
DrGreene Content. (2000). Cotton Swabs and Ear Performations. Retrieved June 7, 2009, from http://www.drgreene.org/body.cfm?id=21&action=detail&ref=461
Neuenschwander, Michael C., Deutsch, Ellen S., Cornetta, Anthony, Willcox, Thomas O., ENT. (2005). Penetrating middle ear trauma: A report of 2 cases. 84(1), 32-35. Retrieved from Academic Search Premier.
Diabetes Question:
ReplyDeleteBlood vessels in the eye can become weak and feeble from the bodies inability to control blood sugar levels. Micro aneurysms can develop in the capillaries over time and fluid leakage can occur. The macula (located near the center of the retina) is affected the most by this fluid leakage and the vision of the patient worsens. Blood vessels can become blocked as they become progressively weaker, which impedes blood flow to the retina. Capillaries can regenerate but the process is slow and the blood vessels do not become very strong. The new capillaries are subject to the same stresses as the original ones, which means they can rupture and cause even more vision impairment. This whole process is called “Diabetic Retinopathy”.
National Eye Institute. (2009). Facts About Diabetes Retinopathy. Retrieved June 8, 2009, from National Eye Institute: Official Sight
Web Sight: http://www.nei.nih.gov/health/diabetic/retinopathy.asp
David E
UV light/eye Question:
ReplyDeleteAbsorption of UV light long term has been associated with eye disease and impairment of eyesight. UV-B is the more damaging than UV-A because it is a higher frequency radiation. Most of the UV-A and UV-B radiation is absorbed by the outer part of the eye (lens and cornea), however some UV radiation does pass through to the retina. Constant sun exposure without wearing sunglasses can cause an increasing amount of damage from UV radiation to the retina. Aging of the retina is linked to UV exposure. Overall, sun protection (covering eyes when exposed to sun) can prevent most of the damage that UV light can cause.
Dillon J, Zheng L, Merriam JC, Gaillard ER. Transmission spectra of light to the mammalian retina Photochem Photobiol 2000 Feb;71(2): 225-9
Bergmanson JP, Soderberg PG. The significance of ultraviolet radiation for eye diseases. Ophthalmic Physiol Opt 1995 Mar:15(2):83-91
David E.
5. How do the scuba masks with pink lenses work to make you see more colors?
ReplyDeleteWater absorbs the colors with the longest wavelengths and lowest energies first. From the visible light spectrum, red is the color with the longest wavelength and lowest energy. Therefore, as one dives deeper, red is the color which is the first to no longer be visible. Color corrective masks restore the balance. However, they do not add red to our field of view but merely remove some portion of the non-red light. Thus allowing less photons to reach our eyes. They work well under daytime or bright condition but may hinder one’s vision during dark diving conditions since they are like colored sunglasses.
Atikkan, Esat. "Skin and Scuba Diving." 2001. Montgomery College. 8 June 2009 http://www.montgomerycollege.edu/faculty/~eatikkan/public_html/pe138.htm.
"Learning Ocean Science through Ocean Exploration: A Curriculum for Grades 6-12." Ocean Explorer. Ed. Valerie Chase. NOAA, 4 Sept. 2008. Web. 8 June 2009. http://www.oceanexplorer.noaa.gov/edu/curriculum/CurricSec_5.pdf.
Michael D.
9. Can cats really see in the dark? How? How are cats’ eyes different than people’s eyes?
ReplyDeleteCats can’t see in complete darkness but they can see clearly in one-sixth the amount of light humans require. This is mostly due to the tapetum lucidum, a layer of reflective cells found behind the retina which humans don’t possess. This reflects the light back to the retina allowing the rods and cones to view more. Also, cats can dilate their pupils to encompass as much as ninety percent of their eye while their protruding eyes allow them to have a wider angle of vision than humans.
"Growing Wild." Utah's Prject WILD Newsletter, 1998. Web. 8 June 2009. http://wildlife.utah.gov/projectwild/newsletters/98winter-gw.pdf.
Michael D.
Do people with lighter colored eyes have more red-eye in pictures?
ReplyDeleteNo, the color of the iris does not affect the result of red-eye in a photograph. Red eye occurs when the flash from the camera is reflected back from the blood vessels in the retina. The eyes appear red because you are actually seeing the blood in the back of your eye. This situation occurs more frequently in dark areas, as the pupils are usually dilated allowing more light to enter the eye. The color of a person’s eyes depends on the pigments in the iris. The iris is responsible for opening and contracting the pupil to allow more or less light it. When a photograph is taken, the red seen comes from the inside of the eye, and is not reflected off the iris.
Sources:
2008. Retrieved Jun, from Newton Web site: http://www.newton.dep.anl.gov/askasci/gen99/gen99087.htm
What limits the frequencies of sound that people can hear? How is this different than other animals? How does the structure of the ear differ among types of animals?
ReplyDeleteThe normal frequency that most humans can hear is about 64-23000Hz. Lower frequencies represent low pitch sounds and higher frequencies represent high pitched sounds. Compared to many other animals, this is a relatively narrow range. Dogs can hear from about 67-45000Hz. Some animals can even hear at extreme frequencies. Cows and elephants can hear as low at 20Hz and bats and mice can hear sounds up in the 100,000Hz range. A major difference that dictates much about what can and can’t be heard is the size of the ear, a big difference between humans and many animals. Also, ear canals between animals vary in size the basilar membrane is responsible for different frequencies; a change in size will change the hearing range of frequencies.
Sources:
Reinier, Plomp (1976). from The Ear As a Frequency Analyzer Web site: http://rintintin.colorado.edu/~chathach/Psychoacoustics%20and%20the%20Ear%20as%20Frequency%20Analyzer.ppt
Strain, George (2009). Deafness. from How Well Do Dogs and Other Animals Hear? Web site: http://www.lsu.edu/deafness/HearingRange.html
2. Can you improve your reflexes?
ReplyDeleteExercising regimes always advertise to improve strength, coordination, and flexibility, key factors linked to reflexes, but does is truly improve ones reflexes? A study conducted on elderly patients was conducted to determine the effect of exercise on postural reflexes, which allows one to react faster to accidents such as slipping or falling or when going to reach for something. The study placed the patients into two groups: one undergoing agility training and the other stretching/weight-lifting training. The study concluded an increase in postural reflex for both types of exercise but with greater improvements from the agility training. Some exercises included in agility training were figure eight walking and rapid knee raises while standing; some exercises were also done with eyes closed. It’s conclusive to say one can improve reflexes with exercise of muscles but also task specific exercises.
Marigold, D.S., Eng, J.J., Dawson, A.S., Inglis, J.T., Harris, J.E., & Gylfadottir, S. (2005). Exercise Leads to Faster Postural Reflexes, Improved Balance and Mobility, and Fewer Falls in Older Persons with Chronic Stroke. American Geriatrics Society, 53(3), 416-423. Retrieved from Academic Search Premier database.
-Dahlia K.