What do you mean by astigmatism and presbyopia, Biology

Assignment Help:

Q. What are astigmatism and presbyopia?

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

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


Related Discussions:- What do you mean by astigmatism and presbyopia

Is protein collagen has a high proportion of glycine, The protein collagen ...

The protein collagen has a high proportion (20% or more) of A. asparagine and glutamine B. proline and hydroxyproline C. glycine D. both A and B E. both A and C F

Excretory system - uriniferous tubule, URINIFEROU S TUBULE - Unit of...

URINIFEROU S TUBULE - Unit of kidney. 3-5 cm. long (30 mm). Total length of nephrons is 65 km. A tubule consists of - 1 .       Malpighian capsule           (

Explain the rapport building, Q. Explain the Rapport Building? Maintain...

Q. Explain the Rapport Building? Maintaining good relationship with the client is very important in counselling. This will help you to gain trust, confidence of the client and

Determine pull-ups test for check the body strength, Determine Pull-ups tes...

Determine Pull-ups test for check the body strength? This test is also done to measure upper body strength or endurance by maximum number of pull-ups completed. Subject hangs f

Embryology, what is meaning of haustoria

what is meaning of haustoria

Define protein stabilized food emulsions, Define Protein Stabilized Food Em...

Define Protein Stabilized Food Emulsions? Many food products are emulsions (eg. milk cream, ice creams, cream, butter etc.) and protein constituents often play a major role in

Exogenous pathway, In the typical Western diet approximately 80-140 G trigl...

In the typical Western diet approximately 80-140 G triglyceride and 0.5-1.5 G cholesterol are eaten daily. Following digestion, absorption and reesterification, triglyceride and c

Micro-organisms, Micro-organisms: The micro-organisms mixed up i...

Micro-organisms: The micro-organisms mixed up in aerobic absorption and their activities are the same as those found in nature. The organic compounds are oxidised to H

Define epithelial tissue, Epithelial tissue the cells in animals which are...

Epithelial tissue the cells in animals which are closely packed in either single or multiple layers, and which cover internal and external surfaces both of the animal body. It is

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