JOURNAL ENTRY WEEK 2
Investigate the two types of sight defect- long-sightedness and short sightedness.
Find the following information:
Long sightedness or Hyperopia
a. what causes the defect
Hyperopia has many different causes with the main one being genetics (the problem is inherited from your family). Other causes are diabetes, microphthalmia (small eye syndrome) and fovea hypoplasia (a condition where there is a problem with the blood vessels in the retina)
b. the symptoms displayed
The main symptoms that are displayed by a patient diagnosed with Hyperopia are persistent headaches, eyestrain, inability to work on computers, excessive blinking and dislike or avoidance of reading.
c. propose what sort of lens may be used to correct each vision.
The lens that would be most suitable to correct Hyperopia is a convex lens. A convex lens is chosen because it moves the image of a distant object forward onto the retina, therefore giving the patient a closer focus or an object.
Short-sightedness or Myopia
a. what causes the defect
Myopia has a wide range of causes. Some of the main ones are genetics, near work e.g sitting close to the tv and working low light working conditions e.g reading in the dark.
b. the symptoms displayed
The main symptoms that are displayed by a myopic patient include blurred distance vision, frequent eye squinting and eyestrain.
c. propose what sort of lens may be used to correct each vision
The type of lens that is used to correct myopic vision is a concave lens. This is because a concave lens bends the incoming light rays slightly outwards therefore an image is produced further back on the retina.