--%>
Assignment Help - homework help

Define the terms astigmatism and presbyopia

Define the terms astigmatism and presbyopia?

E

Expert

Verified

Presbyopia is the visual impairment in which there is a loss of cililary muscle strength therefore dropping the capability of crystalline lens to adjust images of close objects onto the retina. In presbyopia, the near point of vision becomes more far-away. The disease usually takes place in old people. Astigmatism is caused by the irregular shape of refractive structures, mostly the cornea. In astigmatism, a single object-point might generate more than one image onto the retina and therefore the vision becomes distorted.

   Related Questions in Biology

  • Q : Constituent elements of blood Write

    Write down the constituent elements of blood?

    		•
  • Q : Explain synthetic auxins Explain the

    Explain the synthetic auxins and specify their uses?

    		•
  • Q : How calcium ions contribute in the

    How do calcium ions contribute in the muscle contraction? Why do both muscle relaxation and muscle contraction spend energy?

    		•
  • Q : Knowledge Management - Organizational

    "Knowledge is information that changes something or somebody - either by becoming grounds for actions, or by making an individual (or an institution) capable of different or more effective action." Like many other concepts and practices in management and organizational behavior, the exact

    		•
  • Q : Hormones secreted by adrenal medulla

    Explain which hormones are secreted by the adrenal medulla and their respective functions?

    		•
  • Q : State Production Forecasting Production

    Production Forecasting: It means to estimate the future demand for services and goods. It too estimates the resources that are needed to produce those services and goods. Such resources comprise human resources, financial and material resources. There

    		•
  • Q : Amount of mitochondria Why do cells of

    Why do cells of nephron tubules have large amount of mitochondria?

    		•
  • Q : Ionic product of water Define the ionic

    Define the ionic product of water. Determine its value?

    		•
  • Q : Features of Perception - Organizational

    Some of its features are as follows: I. Perception is the intellectual process through which a person selects the data from the environment, organizes it, and obtains meaning from it. II. Perception is a basic cognitive or psychological process. The manner in which a person percei

    		•
  • Q : Define Breath Breath forms the very

    Breath forms the very root of our survival. Untiringly, unhindered and without a pause, it makes its way through all bodily pathways, while being silently and secretly hidden. The type of breath varies with different moods of a person. The cells in ou

    		•