what causes presbyopia

Presbyopia is caused when the centre of the eye lens hardens making it unable to accommodate near vision. This condition generally affects almost everyone over the age of 50 - even those with myop..

Presbyopia is caused when the centre of the eye lens hardens making it unable to accommodate near vision. This condition generally affects almost everyone over the age of 50 - even those with myopia. Eyeglasses with bifocal or progressive lenses are prescribed to correct or imp..

In lanthanides, the nuclear charge increases by one unit at each successive element and this new electron enters the 4f-subshell. Due to the peculiar shapes of f-orbitals, there is imperfect shielding of electrons from the nuclear attraction. As a result of this the size of lanthanide atoms decrea..

Mendeleev's table was unable to explain the cause of periodicity among element..

Causes of Cancer - A chemical or other environmental agent that produces cancer is called a carcinogen. The world Health organisation estimates that carcinogens may be associated with 60 - 90% of all human cancer. Depending upon their mode of action carcinogens are of 3 types. (1) Carcino..

A chemical or other environmental agent that produces cancer is called a carcinogen. The world Health organisation estimates that carcinogens may be associated with 60 - 90% of all human cancer. Depending upon their mode of action carcinogens are of 3 types. (1) Carcinogens that cause alt..

The ultimate cause of pollution is human activity itself. Pollution is a human contribution to nature. Science has evolved technologies and technologies have helped the human welfare. In the process, the pollution has been a part of technology and therefore a part of human miseries...

Shortening of the eyeball, that is, the eyeball becomes smaller Increase in focal length of the eye lens Let us now see how this defect is rectified. A long sighted eye forms image of a nearby object behind the retina. Thus, long sightedness is due to the decreased converging power of the le..

In order to know the causes for deviations from ideality, Van der Waal pointed out the faulty assumption that were made in formulating the kinetic molecular model of gases. The assumption that the volume occupied by the molecular mass is negligible as compared to the total volume of th..

Many factors contribute to the extinction of wild lif..