Can you explain myopia and hypermetropia, Biology

Assignment Help:

Q. How can the visual deficiencies known as myopia and hypermetropia be optically explained?

Myopia is the visual condition in which the images are formed previous to (in front of) the retina. Hypermetropia is the visual condition in which the point of image formation is further than (behind) the retina. Actually myopia is due to an increase in the distance between the crystalline lens and the retina, generally caused by a slight flattening of the eyeball and in hypermetropia the retina is too close to the crystalline lens due to slight shortening of the eyeball.

In myopia the far point and the near point of vision come closer (the refractivity of the crystalline lens that corresponds to the maximum distension capacity of the ciliary muscles isn't enough to provide visual accommodation). In hypermetropia the ciliary muscles aren't able to contract more to compensate the inadequate position of the retina that is the near point becomes more distant.


Related Discussions:- Can you explain myopia and hypermetropia

Measurement of solar energy input-radiation instruments, Measurement of sol...

Measurement of solar energy input A variety of instruments have been designed to measure the energy of solar radiations of all wavelengths as well as of a particular range of w

Common disease of pig, COMMON DISEASE OF PIG  - 1 .       FOOT AND MO...

COMMON DISEASE OF PIG  - 1 .       FOOT AND MOUTH DISEASES 2 .       ANTHRAX 3 .       TUBERCLOSIS 4 .       SWINE FEVER - Charactrized by high fever, d

Microorganisms, methods of isolating and purifying two useful products from...

methods of isolating and purifying two useful products from microorganisms

Cell wall, Cell wall is the structure produced by some of the cells outsid...

Cell wall is the structure produced by some of the cells outside their cell membrane; variously composed of the chitin, peptidoglycan, or cellulose.

Techniques of blood pressure recording, Precautions It is a common obs...

Precautions It is a common observation that BP recordings are variable when taken by different individuals. To decrease this variability it is important that certain precautio

How many layers in retina, How many Layers in retina The retina is comp...

How many Layers in retina The retina is composed of  ten  layers: a:)  Pigmented epithelium (outermost layer), b)  Neusoepithelium, rods and cones  (photoreceptors), c

List the requirements of implant materials, List the requirements of implan...

List the requirements of implant materials. a) Biologically compatibility: an ideal implant material will elicit mainly physiological reactions within the surrounding tissues (

What is phagocytosis and phagosomes?, Protozoans ingest food by phagocytosi...

Protozoans ingest food by phagocytosis, and consequently, the ingested food is surrounded by a plasma membrane creating a food vacuole, or phagosome. Digestion does not start until

Divisions of meiosis, Divisions of Meiosis: Meiosis is characterized by ...

Divisions of Meiosis: Meiosis is characterized by two nuclear divisions, meiosis I and meiosis II. • The first division is a reduction division. • The second meiotic divis

How different are oxyhemoglobin and hemoglobin, How different are oxyhemogl...

How different are oxyhemoglobin and hemoglobin? Where is it expected to find a higher concentration of oxyhemoglobin, in peripheral tissues or in the lungs? Oxygen-bound hemogl

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