How To Diagnose Nearsightedness & What Is The Best Medicine For It?
Nearsightedness or myopia is a refractive disorder of the eye that causes distant vision unclear or blurred. The near vision remains unaffected in this condition. It is a common disorder and it mostly affects children in the adolescent age group. It is becoming a significant public health concern with its increasing rate of incidence. Severe nearsightedness is also one of the leading cause of blindness or loss of vision among other disorders of the eye such as retinal detachment, macular degeneration, cataract, and glaucoma.(1)
Nearsightedness occurs when the eyeball is too long or the cornea is too convex (has a lot of curvatures) that prevents the light rays from falling directly on the retina. As a result of this, the image that is processed by the brain is blurred. The exact cause of nearsightedness is not known. It is known to be hereditary in most cases and some evidence also shows that too much stress on the eyes or too much close work can lead to myopia or nearsightedness.(1)
How Do You Diagnose Nearsightedness?
The patient will complain of persistent headache while working and seeing distant objects blurred or unclear. There could be undue strain present in the eye while performing day to day activities and a person might have to squint to see objects that are far away.(1)
An eye examination is performed by the ophthalmologist that will include testing of the vision (by asking you to read letters and alphabets on a chart placed at a distance on the other side of the room) and examining the eye thoroughly in detail. It is done by first dilating the pupils wide so that the optic nerve and retina can be examined closely. A retinoscopy will show whether the person is nearsighted or farsighted. A phoropter will measure the degree of refractive error present in the eye that will help in determining the correct prescription lens for a person.(2)
What Is The Best Medicine For It?
There is no best medicine for nearsightedness. The treatment of nearsightedness depends upon the severity of the condition. Simple nearsightedness is relatively easy to treat with spectacles and contact lenses. Pathological nearsightedness includes rapid changes in the eyeball along with other co-morbidities (cataract, glaucoma and macular degeneration) that can lead to severe progression of nearsightedness and ultimately loss of vision or blindness.(2)
Atropine is used in many children to control nearsightedness and its progression with time. Topical atropine dilates the pupil and relaxes the eye completely thereby preventing the need for accommodation. The results vary from person to person and are usually short term. The effect usually wears out after 7 to 10 days. It limits the use of spectacles and contact lenses in nearsighted people. When this therapy fails a doctor will prescribe the use of spectacles while reading or permanently. Contact lenses can also be used by adults who do not want to use spectacles. They should be used only after consulting a doctor as they can lead to drying of the conjunctiva with improper use. Pirenzepine gel also used twice a day has shown to improve nearsightedness and halt its progression in children.(1)
Other treatment options include surgery to correct the refractive error. Refractive surgery is commonly done (LASIK and photorefractive keratectomy) in the early teens when the optic error has stabilized, which changes the shape of the cornea so that better light can be focused on the retina. LASIK removes the layer of tissue from the cornea that reshapes it and later left to heal by putting the flap back in position. Certain side effects were experienced by the patients such as glare, halos, and starbursts following the surgery. The phakic intraocular lens can be used in people who have a very thin cornea that does not allow the use of LASIK and PRK. These lenses are placed inside the eye via surgery that helps in focusing the light on the retina.(2)