Ray Optics and Optical Instruments

Myopia

Myopia is a kind of disorder which is very common in eyes. Myopia or near-sightedness is a common vision disorder in which a person cannot see the objects far from him or her. In this type of vision disorder, the picture of the object does not focus on the retina of the eye but before it. Due to this, objects look blurry. Myopia may develop gradually or rapidly and its development occurs between early school years to teenage years. This disorder may run in the families also. This disorder is curable and one can compensate myopia by wearing proper eyeglasses, contact lenses, or by refractive surgery.

Myopia

Symptoms and Causes

The main cause of myopia is the structure of the eye. In this disorder, the image of an object is created well before the retina and due to this effect, the image becomes blurring.

In normal vision, the rays are coming and passing through the cornea and making the image on the retina. Whereas in the case of myopia; the rays coming from the cornea, are forming the image well before the retina. As the image forms before the retina, a blurry image will be created on the retina. When the eyeball becomes too long or the cornea becomes too curved, this vision disorder occurs. Another term for myopia is a refractive error, which doctors generally use.

Symptoms of Myopia

Near-sightedness or short-sightedness is another term that describes myopia. The symptoms of this disorder may include:

  1. Visions get blurred when looking at distant objects
  2. Headache caused by strain in eyes while looking at objects
  3. Squinting
  4. Children because of myopia, often have trouble to see the blackboard in school.
  5. Scattering of light and blurry images at night
  6. Blinking eyes excessively and rubbing frequently.

Causes of Myopia

One of the causes of myopia is a hereditary disorder. Myopia also happens due to a lot of close work like typing, reading, watching/operating TV/computers closely and using mobiles. Using mobiles/TVs/computers, increase the screen time and hamper the eyes significantly. Another cause of this type of disorder is uncontrolled diabetes. Advanced stages of myopia lead to the other serious risks to eye conditions like myopic macular degeneration, retinal detachment, glaucoma, cataract and sometimes partial visual impairment which lead to complete blindness.

Today’s young generation suffers from myopia due to elongation of eyeballs or the bulging of the cornea. Bulging of cornea refracts the rays pass through it in such a way that the images created before the retina and this leads to a blurry image.

Measurement and Treatment of Myopia

Myopia or short-sightedness is measured in optical units called dioptres. Dioptre unit is nothing but the reversal of the length in meters by which a person can see the objects. For myopia, the power of the lenses is represented with numbers bearing a negative sign in front of it. Concave lenses are used to treat myopic visual disorder.

To calculate the power of the concave lens, the formula is:

\(\frac{1}{f}\) = \(\frac{1}{f_{1}}\) + \(\frac{1}{f_{2}}\)

Where,

  • f is the effective focal length
  • \(f_{1}\) is the focal length of the eye and
  • \(f_{2}\) is the focal length of the lens required.

A diverging or concave lens is the only solution to prevent myopic vision disorder to increase. These concave lenses can be used in the form of spectacles or as contact lenses. Another way to correct myopic vision disorder is to go through refractive surgery. Since myopia is not a disease like cancer or diabetes; it is a condition of the eye that cannot be treated by any medicine, massage, or herbal remedies. So, once it happens, one should start wearing the correct numbered glasses all the time to avoid further deterioration the eyes.

Risk Factors and Complications in Myopia

After the development of myopic visual disorder, certain risks may increase like genetic transfer and environmental conditions. Genetic transfer to the child becomes more prominent when both the parents are near-sighted. A close work like typing, reading or watching TVs/mobiles closely and spending less time outdoors also increases the chance of near-sightedness.

Several complications may also generate which can be termed from mild to severe. These are:

Eye strain: Due to myopia, people have to strain their eyes to focus on the objects. This leads to eyestrain or headaches.

Financial burden: due to near-sightedness, people have to visit for a regular eye check-up and medical treatment which added up their financials. Cost of corrective lenses is also an additional cost to them. In some cases, people may lose their jobs due to myopia.

Other eye problems: When the problem of near-sightedness is not attended properly in the initial stages, this may increase the risk to severe eye defects like retinal detachment, glaucoma and cataracts.

Impact on quality of life: Suffering from myopia and not using the corrective lenses ruins the quality of life. The limited vision may detract a person to enjoy day-to-day life. He/she feels helpless without spectacles.

FAQs on Myopia

Q.1: What is myopia and how does it affect a person’s life?

Answer: Myopia is a kind of disorder which is very common in the eyes. Myopia or near-sightedness is a common vision disorder in which a person cannot see the objects far from him or her. A near-sighted person can do the work on the computer or read a book but without the eye-gear, he/she will not be able to recognize the unknown faces across the room or drive safely.

Q.2: What are the reasons for myopia?

Answer: One of the reasons for myopia is a hereditary disorder. Myopia also happens due to a lot of close work like typing, reading, watching/operating TV/computers closely and using mobiles. Using mobiles/TVs/computers, increase the screen time and hamper the eyesight significantly. Another cause of this type of disorder is diabetes. Advanced stages of myopia lead to the other serious risks to eye conditions like myopic macular degeneration, retinal detachment, glaucoma, cataract and sometimes partial visual impairment which lead to complete blindness. Today’s young generation suffers from myopia due to elongation of eyeballs or the bulging of the cornea.

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