What are presbyopia and astigmatism, Biology

Assignment Help:

What are presbyopia and astigmatism?

Presbyopia is the visual impairment in which there is loss of the cililary muscle strength therefore reducing the capability of the crystalline lens to adjust images of near objects onto the retina. In presbyopia the near point of vision becomes more distant. The disease normally occurs in old people.

Astigmatism is caused by irregular shape of the refractive structures, mostly the cornea. In astigmatism a single object-point might produce more than one image onto the retina and so the vision becomes distorted.

 


Related Discussions:- What are presbyopia and astigmatism

Explain effect of nutrient supplements on drugs, Explain Effect of Nutrient...

Explain Effect of Nutrient Supplements on Drugs? A nutrient or nutrient supplement can alter the pharmacological action of a drug by enhancing the drug effect or by opposing it

Explain what is inversion, Explain what is Inversion ? Inversion is ano...

Explain what is Inversion ? Inversion is another way in which genetic recombination can occur, as seen below. In this case, the change occurs within a chromosome, rather than b

What is the quaternary structure of a protein, What is the quaternary struc...

What is the quaternary structure of a protein? Do all proteins have quaternary structure? The quaternary protein structure is the spatial conformation because of interactions b

What is malabsorption syndrome, Q. What is Malabsorption Syndrome? Did ...

Q. What is Malabsorption Syndrome? Did you know that a major part of the absorption of nutrients takes place in the small intestine and the set of enzymes involved in this proc

Phosphorus cycle, Phosphorus cycle is sedimentary cycle because it does not...

Phosphorus cycle is sedimentary cycle because it does not enter into atmosphere. It can be found on earth in water, soil and sediments. The phosphorus cycle is the biogeochemical c

Radioisotopes, Radioisotopes Radioisotopes are those forms of an elemen...

Radioisotopes Radioisotopes are those forms of an element which exhibit rzdioactivity and so can be used as markers or tracers. For this purpose, we first introduce the radiois

Transgenics considered a threat to the environmental safety, Q. Why are tra...

Q. Why are transgenics considered a threat to the environmental safety? The Transgenics can be dangerous to the whole biosphere since the transfer of genes between species may

Skin, physiology of skin

physiology of skin

Explain gastro-intestinal system, Explain G.I. (Gastro-Intestinal) system? ...

Explain G.I. (Gastro-Intestinal) system? A. Skeletal muscles directly control the movement of substances at the entrance of the G.I. system. B. Smooth muscles control the mo

Explain the term- cerebral ischemia, Explain the term- Cerebral Ischemia ...

Explain the term- Cerebral Ischemia Ischemia refers to any of a group of disorders in which the symptoms are caused by vessel blockage preventing a sufficient supply of blood t

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd