Myopia, also known as nearsightedness is a prevalent refractive disorder of the human eye, i.e. a disorder related to the abnormalities in the shape and size of the eyeball (or other parts of the eye), due to which the eye is not able to correctly focus light on the retina.
In this condition, people are not able to see clearly objects that are far but can see close. Those having myopia usually find it difficult to watch TV or read the blackboard in school.
The most apparent symptom is that distant objects look blurred. Apart from this, some people may also have:
- Eye strain
- Fatigue while driving or during sports activities
- Difficulty in reading road signs or blackboard in schools (for children with myopia)
People with myopia have either extra-long eyeballs or their cornea is more curved due to which the light rays do not bend correctly into the eye, focusing in front of the retina, which is light-sensitive, instead of focusing directly on the retina, thus leading to blurred vision.
Myopia can be inherited in families and its symptoms start appearing in childhood. It may improve or worsen with age if left untreated.
While there is no proper evidence of whether myopia is a inheritable disease, but chances are that children whose parents are nearsighted, either one or both, may develop myopia.
In fact, most of the times, the development of myopia in a person depends on how much care he/she takes of his/her eyes. People who work long hours at a computer, do extensive reading, or perform intense visual activities have greater chances of developing myopia.
Usually, myopia/nearsightedness starts during childhood and gradually worsens around the age of 20.
This doesn’t mean that myopia can’t occur in adults. In fact, it can also develop in adults because of eye stress or due to underlying diseases like diabetes.
Myopia can occur in varying degrees depending on:
- The length of the eyeball,
- How curved the cornea is, and
- How strong the eye lens are.
An eye test by the optometrist (optician) will show how much focusing power your eye has. Optometrists use Diopters to measure the focusing power of eyes. This shows how strong a lens needs to be to produce focused vision.
It is generally written as “-5.00 dioptres (D)”. A minus sign on your glasses or contact lens prescription shows that you have myopia. A higher number means you have greater degree of near sightedness. Lens powers up to -3.00 dioptres (D) come under mild myopia.
- Powers of -3.00 to -6.00D are considered moderate
- Over and above -6.00D is taken as high myopia.
Generally, people have myopia below -6.00D, but sometimes there may be cases of people having higher levels of myopia. The degree of their myopia can decide if there are further complications related to their eyes. People with myopia of up to -6.00D can easily deal with it with help of glasses or contact lenses, and they do not face further problems with their eyes. This is referred to as simple myopia.
In people with high myopia of more than -6.0 diopters or more, there is the risk of retina being detached. Retina is the tissue present at the back of the eye that sends image signals to the brain when light rays fall on it. If it is detached, it will be torn away from the choroid, the tissue lying under it. Retina gets its oxygen supply and other nutrients from the choroid.
People with high myopia have the risk of developing cataract and glaucoma diseases. Cataract is the darkening of eye’s lens. Glaucoma is a set of diseases that impair the optic nerve, which transmits signs from the retina to the brain. Any of these conditions can lead to loss of sight.
People having higher than -6.00D myopia are at risk of few eye conditions that require more extensive treatment rather than correcting it with just contact lenses or glasses. This is called degenerative or pathological myopia, which is a rare condition.
In this condition, the eyeball becomes excessively long that impairs the proper functioning of the retina, the optic nerve, the choroid, and other components of the eyes.
Symptoms of degenerative myopia first emerge in childhood and gradually worsen once adolescence and adulthood is reached. There is no treatment to stop the elongation of the eye; but other complications like retinal detachment, macular edema (which happens due to building up of fluid in the center of the retina), and glaucoma can be corrected.
An eye test by an optometrist can detect if you have myopia. In general cases, contacts lenses, glasses or refractive surgery can easily treat your myopic condition.
The prescription glasses or lenses are meant to support the eye in focusing light on your retina. That corrects your vision.
Nowadays, people opt for eye surgery to correct their as they do not want to wear glasses or contact lenses. Common procedures for treatment of myopia are:
- PRK (Photorefractive keratectomy): In this procedure, a laser is used to shape the mid layer of the cornea of the eye. This helps to flatten/correct the cornea’s curve which was preventing light rays to focus on the retina. After the correction of the cornea curve, the light rays can focus directly on the retina thus producing accurate images.
- LASIK surgery: This is a popular procedure and most preferred surgery for myopia. In this procedure, a laser is used to make a thin flap on the top of the cornea. The cornea is then shaped with another laser and the flap is brought back into its position.
- Orthokeratology: This is a non-surgical method in which a person is made to wear specially designed Rigid Gas Permeable (RGP) or gas permeable contact lenses during the night. These lenses reshape the cornea while sleeping. Once the lenses are removed in the morning, the cornea retains the new shape for a temporary period, and the person is able to see clearly during the day without the help of any eyeglasses or corrective lenses. Orthokeratology also known as corneal refractive therapy (CRT) is effective only for improving mild to moderate levels of myopia for a temporary period. These procedures are used as alternatives to surgery for those persons who are not fit for LASIK or any other refractive surgery due to other health conditions.
- Phakic intraocular lenses (IOLs) are another exclusive alternative for people who have high myopia and whose corneas, being very thin, do not permit LASIK and PRK surgeries. In this condition, Phakic lenses are surgically inserted into the eye to correct the focus of light on the retina.
Myopia is usually diagnosed around the ages of 8 to 12 (as per the National Eye Institute). At this age, the eyes are in the growth stage and the shape of the eyes may also change. A person diagnosed with myopia in childhood may remain nearsighted till adulthood. Other people with diseases like diabetes may also become nearsighted at later stages.
Nearsightedness often results in visual stress as a risk factor. If a person does extensive reading or uses laptops for long hours, he/she may suffer from eye strain.
Nearsightedness or myopia can run in families. If your mother or father or both of them are nearsighted, it is much possible that you inherit the condition from them.
The fast changing lifestyle and use of more technology and computers has further led to increase in the percentage of people being affected by myopia. Research and studies are ongoing to control the development of myopia in childhood itself.
A lot of new techniques have been experimented upon — such as progressive lenses for children, bifocals, and gas permeable contact lenses — that have shown mixed results.
A New Zealand research reported positive results from expressly designed "dual focus" soft contact lenses for controlling nearsightedness in children. These lenses are designed to reduce the inclination for unnecessary lengthening of the eye which causes myopia. Such experimental lenses are still under research and are not available to use unless proper evidence of positive outcome is achieved.
Myth #1: Contact lenses or Glasses will worsen my Myopia
Reality: A common myth is that people think wearing glasses will further degrade their vision. But the truth is that prescription glasses help correct your vision and focus on objects more clearly. If there is any inconvenience like headaches or eye strain while wearing your lenses or spectacles, you need to check the power of your lenses which may be either high or low, thus causing headaches or eye stress. It is suggested that you conduct a comprehensive eye test to know the degree of your nearsightedness and get optimal lens upgrades.
Myth #2: Using lesser Lens Power will control my Myopia
Reality: Absolutely wrong! The lens power is determined only after a comprehensive eye exam by an optometrist. The power is prescribed as per the severity of the refractive error. If you use lesser power lens, it will not help see objects correctly as required and may even worsen the condition of your eyes.
Myth #3: Childhood Myopia will improve with Age
Reality: There is no evidence to this myth. Myopia usually develops in childhood and may continue during adulthood. Also, there is no proof that a person cannot develop myopia in later ages. Lifestyle irregularities and other diseases can trigger the onset of myopia in adults as well.
Myth #4: LASIK Surgery will permanently cure Myopia
Reality: Undergoing LASIK is a proven method of correcting myopia. It helps correct the distorted shape of your cornea, leading to improved light focus. It relieves you from wearing lenses and glasses for long. However, it does not guarantee that myopia will not reoccur in your life. With age and other health conditions, people may experience nearsightedness or other problems in vision.
Ans: Myopia occurs when the distance between your eyes’ front and back parts becomes too long. This is a refractive error which also results from incorrect curvature of your cornea or from thickening of your eye lenses. These abnormalities in the shape and size of eye parts cause light rays to be focused in front of the retina rather than directly on it.
Ans: Common symptom is when you experience difficulties in understanding or seeing far objects easily. You will still have no problems in seeing close objects. You may also get eyestrain and headaches while working or doing computer tasks. Street signs may appear blurred while driving. In all such cases, you need to visit your Ophthalmologist to check your eyes.
Ans: Yes, heredity may be one reason in your chances of developing this problem. If your parents are nearsighted, you may develop this problem as well. However, there are other causes that may lead to this condition apart from getting it from your families.
Getting corrective lenses and eyeglasses can cure the problem that occurs due to myopia. It will help focus light rays correctly on your retina, and you will be able to see better images from a distance.
You may also consider LASIK and other refractive surgeries. Apart from these, yoga and vision therapy are also becoming popular means of maintaining eye health. These are meant to perform eye exercises, thus inducing enhanced coordination of your eyes with the brain.
Ans: Reading glasses (with a plus sign) are convex lenses that move objects far away and reduce accommodation (focusing effort). Distance glasses, called minus lenses, are concave lenses that move objects closer and increase accommodation.
Ans: Plus lenses should be while extensive reading, computer use, while watching TV, and during other activities that require close examination.
Stop wearing them for some time and if the problem persists, consult your eye doctor to examine your eyes.
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