Farsightedness (Hyperopia) and Nearsightedness (Myopia)
Farsightedness and nearsightedness are common vision issues caused by refractive errors, which occur when a misshapen eyeball, cornea, or lens does not properly bend (refract) the light that enters the eye. As a result, the light does not focus correctly on the retina, causing distorted vision.
What Are the Symptoms of Farsightedness and Nearsightedness?
Farsightedness causes nearby objects to appear blurry while faraway objects remain clear. This can lead to difficulty performing tasks that require close visual focus, such as reading, writing, drawing, and working on a computer.
Nearsightedness causes faraway objects to appear blurry while nearby objects remain clear. This can lead to early fatigue while driving, playing sports, and viewing objects positioned more than a few feet away.
Both types of refractive errors can also cause squinting, headaches, and eyestrain, including burning and aching sensations in or around the eyes.
What Causes Farsightedness and Nearsightedness?
Farsightedness occurs when the eyeball is too short, the cornea is too flat, or the lens has hardened and become inflexible with age. As a result, the light entering the eye is under-focused and forms an incomplete image on the retina, making nearby objects look blurry.
Nearsightedness occurs when the eyeball is too long or the cornea is excessively curved. As a result, the light entering the eye is focused in front of the retina instead of directly on it, making faraway objects look blurry.
What Are the Risk Factors and Complications Associated With Farsightedness and Nearsightedness?
Anyone can have a refractive error, although the risk is higher with a family history. Usually, these vision issues become apparent during childhood, although farsightedness often develops and worsens along with the natural aging process. Some studies indicate that children who use computers or smart devices for long periods have an increased risk of developing nearsightedness.
Possible complications of an untreated refractive error include:
- Reduced quality of life
- Reduced safety (e.g., driving with uncorrected myopia increases the risk of accidents)
Additionally, severe myopia can increase the risk of retinal detachment, glaucoma, cataracts, and other serious eye conditions.
What Are the Treatment Options for Farsightedness and Nearsightedness?
The goal of treating refractive errors is to improve vision by helping to properly focus light on the retina. In most cases, this can be achieved with the use of corrective lenses or refractive surgery.
Prescription lenses can treat farsightedness by counteracting the decreased length of the eye or the decreased curvature of the cornea. Likewise, they can treat nearsightedness by counteracting the increased length of the eye or the increased curvature of the cornea.
Types of corrective lenses include:
- Eyeglasses – Prescription lenses are mounted in a frame that is worn on the face, resting mostly on the ears and nose so that the lenses are positioned directly in front of the eyes.
- Contact lenses – Thin, curved prescription lenses are placed on the tear film that covers the surface of each eye.
Refractive surgery is an outpatient procedure that involves the use of a laser to reshape the cornea so that the light traveling through it will properly focus on the retina. The goal is to reduce or eliminate the need for corrective lenses. The types of refractive surgery include:
Laser-Assisted In Situ Keratomileusis (LASIK)
After applying numbing eye drops, the surgeon places an eyelid holder and suction ring on the eye to prevent blinking and movement. Using a femtosecond laser programmed with the patient’s specific eye measurements, the surgeon makes a thin flap in the cornea, then folds the flap back and uses an excimer laser to precisely sculpt the cornea. Finally, the surgeon folds the flap back into place, where it will settle and begin healing within minutes.
Laser-Assisted Subepithelial Keratectomy (LASEK)
After applying numbing eye drops, the surgeon temporarily removes the outer layer of the cornea (epithelium) by applying an alcohol-based solution to loosen the epithelial cells and using an ultra-thin sheet to move the cells to one side. Using a laser, the surgeon then reshapes the deep corneal tissue based on the calculations determined to be appropriate to correct the refractive error in the patient’s vision. Finally, the surgeon slides the single-cell-layer epithelium back over the cornea and applies a bandage contact lens to protect it as it heals.
Photorefractive Keratectomy (PRK)
After applying numbing eye drops, the surgeon uses either an excimer laser or a special rotating brush (Amoils brush) to remove the central portion of the epithelium and gain access to the middle layer of the cornea. Using an excimer laser, the surgeon then sculpts the corneal tissue based on the calculations determined to be appropriate to correct the refractive error in the patient’s vision. Finally, the surgeon applies a bandage contact lens to protect the cornea as it heals.
Small Incision Lenticule Extraction (SMILE)
After applying numbing eye drops, the surgeon uses a femtosecond laser to cut a small disk-shaped piece out of the central corneal layer (lenticule), then removes the lenticule through four tiny corneal incisions. As a result, the cornea is reshaped to correct the refractive errors in the patient’s vision. SMILE can only correct relatively simple forms of nearsightedness.
Schedule Your Eye Exam Today
If you have questions about farsightedness or nearsightedness, you can talk with an ophthalmologist in Florida Medical Clinic’s Department of Ophthalmology. To schedule an appointment for an eye exam, click here.
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