Describe different parts of the human eye. Describe two major defects of the human eye and how they are remedied.
The human eye is a complex organ that consists of several parts, including:
- Cornea: The transparent outer layer of the eye that helps to focus light.
- Iris: The coloured part of the eye that regulates the amount of light that enters the eye.
- Pupil: The black circular opening in the centre of the iris that allows light to enter the eye.
- Lens: The clear, flexible structure located behind the iris helps to focus light on the retina.
- Retina: The innermost layer of the eye that contains photoreceptor cells (rods and cones) that detect light and transmit visual signals to the brain.
- Optic nerve: The nerve that carries visual signals from the retina to the brain.
Now, coming to the two major defects of the human eye and their remedies:
- Myopia: Also known as nearsightedness, myopia is a condition in which a person can see objects clearly up close but has difficulty seeing objects that are far away. This occurs when the eyeball is too long or the cornea is too curved, causing light to be focused in front of the retina rather than on it.
Remedy: The most common remedy for myopia is wearing corrective eyeglasses or contact lenses that contain a concave lens, which helps to redirect light so that it focuses directly on the retina.
- Hyperopia: Also known as farsightedness, hyperopia is a condition in which a person has difficulty seeing objects up close but can see distant objects clearly. This occurs when the eyeball is too short or the cornea is too flat, causing light to be focused behind the retina rather than on it.
Remedy: The most common remedy for hyperopia is wearing corrective eyeglasses or contact lenses that contain a convex lens, which helps to redirect light so that it focuses directly on the retina. In some cases, surgery may be performed to reshape the cornea and improve vision.