Myopia, or nearsightedness, is a common refractive error wherein near objects appear clear and distant objects appear blurry. In a person with no refractive error, a light stimulus entering the eye passes through the cornea and lens. The formed image is focused on the retina, the tissue that communicates with the brain for visual recognition. In myopia, there is an elongation of the eyeball exceeding its normal measurement, causing images to be focused in front of the retina. The opposite happens in hyperopia or farsightedness, wherein the length of the eyeball is shorter, causing images to be focused behind the retina.
Myopia typically affects both eyes, but it may be asymmetric which means that one eye can have worse vision than the other. It can also stem from strong family history, especially when both parents are affected. This refractive error usually starts at a young age and progresses through teenage years. Since children do not usually complain of blurry vision, guardians or school teachers are frequently the first to notice and report a child’s visual discomfort. It manifests as:
difficulty reading prints projected on a screen;
reading a book or tablet at a near distance; and
poor writing skills as one cannot correctly replicate what is written on the board due to poor vision.
Other symptoms may include floaters and image distortion.
Simple myopia is the most common refractive error seen in eye clinics nowadays, but some cases progress to high myopia and pathologic myopia, which are less common but severe forms. In high myopia and pathologic myopia, the eyeball lengthens to a certain measurement enough to cause complications such as neovascularization or abnormal blood vessel in the retina, thinning of the sclera (the white part of the eye), degeneration of the retina, retinal detachment, etc. These complications can lead to blindness if left untreated.
In an eye clinic, it is common practice to do some diagnostic evaluations aside from refraction alone. Aside from knowing what type of refractive error an individual has, doctors would want to determine its severity and if there is a need for frequent monitoring. Some tests may also be used for prognostication purposes, especially in severe cases. Routine examination includes visual acuity testing and examination of the fundus (through a dilated or non-dilated pupil) with or without photography, which is a good baseline for all patients with myopia. In cases of myopia with sudden onset of new symptoms such as floaters or a high myopia with a minus (-) refraction greater than 6.00D, indirect ophthalmoscopy through a dilated pupil is added to the routine examination because these predispose the retina to pathologic changes. Additional tests may include ultrasound examination for the determination of the axial length of the eyeball, angiography if there is suspected neovascularization, and optical coherence tomography to assess the status of the retina from a different view or section.
Since myopia is a refractive error, its management relies on corrective glasses that will refract the light to its supposed location. It is, however, expected that refraction will increase or change as long as the eyeball lengthens and until it stabilizes. It is advisable that refraction is done by an ophthalmologist so that monitoring of the fundus (the back of the eye) and observation for any pathologic changes in the retina will be done. In this kind of setting, progression to more severe forms will be detected early as well. The vision-threatening complications of high myopia and pathologic myopia may require surgical intervention.
It is prudent to correct myopia, or any refractive error occurring in a young child, as soon as possible to prevent potential long term complications such as amblyopia (lazy eye) and strabismus (eye deviations), which are both different eye disorders requiring different treatments. Eye development, in terms of anatomy and physiology, happens in infancy and childhood. Visual disturbances occurring during these stages can affect the communication of the eye with the brain for normal visual maturation. Refractive errors (at a certain measurement), eye deviations, and deprivation of light stimulus (media opacities, swelling of the eyelids, etc.) entering the eye are common disturbances that can affect a child’s visual development. In infant and pre-verbal patients, whose complaining abilities are even less reliable than preschool children, the timing of consult will solely depend on the parent or guardian.
Some clues that a baby is having visual difficulties are:
failure to recognize faces;
eye deviations (this can be an outcome or causative mechanism); and
poor ability to grasp colorful toys.
A baby who does not blink at all with any given stimulus denotes a very poor vision, even blindness. Managing refractive errors in a young child is different from how refractive problems are managed in adults. It is best to consult a pediatric ophthalmologist for such cases. Examinations are a little complicated and may require several clinic visits. Parents’ or guardians’ cooperation and education are very important and scheduled clinic visits should be followed carefully.
Most myopic individuals reach a stable corrected visual acuity that is considered good or functional. For simple myopia, corrective glasses or contact lenses that are fitted properly are generally good options for its management, since these are non-invasive procedures. But for some individuals where wearing of glasses or contact lenses are not advisable nor acceptable, an ophthalmologist may offer several options of surgical procedures. Thorough screening is needed to know if one is a good candidate for a surgical procedure because not all refractive errors are advised or suitable for surgical intervention.
In summary, myopia or nearsightedness is a common refractive error, which usually runs in the family, starts at a young age, and is a bilateral condition that can be asymmetric. Management is usually getting the best corrected visual acuity through refraction and wearing of correctly prescribed glasses. If dizziness or headache are experienced, consult your ophthalmologist to recheck and repeat the refraction, and to rule out any other comorbidities. Just like with any other disorders, management of this case is still individualized. Some may require entirely different treatment from what is usually being practiced. Never hesitate to consult a doctor.