A person suffering from myopia, also called as shortsightedness or nearsightedness will have difficulty in viewing distant objects, but will be able to see the nearby objects clearly. It is one of the most common refractive errors among young adults; it typically starts developing during childhood and progresses rapidly or gradually. The eye gets elongated from front to back, thus the light entering the eye focus in front of the retina and not directly on it. Also, if the lens inside the eye is too thick or the cornea is too curved for the length of the eyeball, a person will not be able to see distant things clearly. Myopia rends to run in the families, doctors also attribute eye fatigue as one of the reasons.
Types of Myopia
Myopia is not a disease and is rather an eye focusing disorder. However, if it exceeds certain graduation it is called high Myopia. Simple myopia is not considered a visual disease and is below 6 diopters. When the patient exceeds 6 diopters, it is then considered an eye disease and is termed as high myopia.
There are three types of Myopia-
- School- age myopia- It usually occurs in between the age of 6-18 years and is expected to stabilize by late teens to early twenties. It is quite common in industrialized and urban cities or due to less exposure to sunlight and is also associated with higher IQ. More time spent in reading or academia also affects the magnitude of myopia.
- Pathologic myopia- the extreme and abnormal elongation of the axial length of the eye causes pathologic myopia. Also, it does not change, mostly before 6 years of age.
- Adult onset- it gets affected by accommodative anomalies and also by those occupations that require more of near vision work. Around 20- 40 years of age are termed early adulthood, above 40 years is late adult.
Symptoms of Myopia
The symptoms of myopia are quite easy to recognize. Those having myopia see nearby object clearly, but things farther away cause strain to the eyes. Schoolchildren have a trouble in reading what’s written on the whiteboard or blackboard.
If a child has myopia-
- He/she will sit at the front of the classroom
- Lacks interest in those activities that require good distance vision
- Sits close to the TV screen
Apart from blurred vision, the child might
- Objects or books close to the face
- Get frequent headaches
- Frown and squint
Myopia can lead to poor work performance, performance in school or sports. Sever myopia can lead to chances of more serious vision problems like-
- Premature cataracts
- Macular degeneration
- Retinal detachment
Preventing nearsightedness in your child is cost free and quite simple. Ensure that the child does not read in dim light and spends more time outside. Exposure to sunlight lowers down the risk of nearsightedness.
A basic eye exam, which includes an eye health exam and refraction assessment is done for diagnosing nearsightedness.
Treatment of myopia
In order to manage and treat nearsightedness, following things are done.
Corrective lenses counteract the increased curvature of the cornea of the increased length of the eye
- Contact lenses are worn on the eye and are available in a variety of designs and materials, rigid and soft, gas permeable in combination with toric, spherical and multifocal designs.
- Eyeglasses are safe and simple to use and are available in a wide variety which includes trifocals, bifocals, single vision and progressive multifocal.
- Laser-assisted subepithelial keratectomy (LASEK) – an ultra thin flap is created in the cornea’s outer protective cover called as epithelium. The laser is then used to reshape cornea’s outer layers, the curve is flattened and the epithelium is then replaced.
- Photorefractive keratectomy (PRK)- just like LASIK, laser is used to reshape the cornea, but the epithelium is not removed, rather it grows back naturally as per the cornea’s new shape.
- Laser-assisted in situ keratomileusis (LASIK) – in this procedure, a thin, hinged flap is made in the cornea and then laser is used to remove the inner layers of the cornea to flatten the domed shape. Patients recover quite fast and cause less discomfort as compared to other surgeries.
To stop or slow the progression of myopia following therapies are effective-
- Increased time outside- researchers think that exposure to the ssun’s UV rays during adolescence and early adulthood changes the molecular structure of the cornea and sclera and aids in maintaining a normal shape.
- Topical medication, atropine- topical atropine drops slows the progression of myopia.
- Peripheral defocus modifying contact lenses- such contact lens corrects myopia and keeps the eyes evenly focused on the periphery of the retina.
- Orthokeratology- a rigid, gas permeable contact lenses are worn for several hours in the day to even out the curvature of the eye. As the eyes gradually return to formal shape, it can be worn less frequently and can be eventually discontinued.