Myopia, commonly known as nearsightedness, is a widespread vision condition where distant objects appear blurry while close objects remain clear. This occurs when the eye focuses light in front of the retina instead of directly on it, often due to an elongated eyeball or an overly curved cornea. Various methods are available to address this refractive error and improve visual clarity.
Corrective Lenses
Corrective lenses offer the most common and immediate solution for managing myopia. These lenses work by altering how light enters the eye, ensuring it focuses precisely on the retina. Eyeglasses achieve this with concave lenses, which are thinner in the center and thicker at the edges. These “minus power” lenses diverge incoming light rays, pushing the focal point backward onto the retina, thereby sharpening distant vision.
Contact lenses function similarly by sitting directly on the eye’s surface, providing a wider field of view without frame obstructions. They use a concave design to refocus light onto the retina. Both offer effective, non-invasive ways to achieve clear vision without permanent changes to the eye’s structure.
Refractive Surgery
Refractive surgery provides a more permanent approach to vision correction by physically reshaping the cornea. This alteration allows light to focus correctly on the retina, reducing or eliminating the need for glasses or contact lenses. The most recognized procedure, LASIK (Laser-Assisted In Situ Keratomileusis), involves creating a thin, hinged flap on the cornea’s surface using a microkeratome blade or a femtosecond laser. This flap is then lifted, and an excimer laser precisely removes microscopic amounts of underlying corneal tissue to correct the refractive error. The flap is subsequently repositioned, healing naturally without stitches.
Another common procedure, PRK (Photorefractive Keratectomy), differs from LASIK as it does not involve creating a corneal flap. Instead, the outermost layer of the cornea, the epithelium, is gently removed. An excimer laser then reshapes the exposed corneal surface. The epithelial layer regenerates over a few days.
SMILE (Small Incision Lenticule Extraction) is a newer, minimally invasive technique that uses a femtosecond laser to create a small, lens-shaped lenticule within the cornea. This lenticule is then extracted through a tiny incision, reshaping the cornea without creating a large flap. Candidates for these procedures have stable prescriptions, are of a certain age, and possess good overall eye health.
Myopia Control Strategies
Myopia control strategies for children aim to slow or halt the progression of myopia, rather than simply correcting existing vision. This prevents the eye from elongating further, which can lead to higher degrees of nearsightedness and an increased risk of associated eye conditions in adulthood. One method involves low-dose atropine eye drops, typically in concentrations ranging from 0.01% to 0.05%. While the exact mechanism is still being researched, atropine is thought to influence muscarinic receptors in the eye, which regulate eye growth signals. It may also affect dopamine levels in the retina, a neurotransmitter linked to eye growth regulation.
Orthokeratology, or Ortho-K, involves wearing specially designed rigid gas-permeable contact lenses overnight. These lenses gently reshape the cornea while sleeping, temporarily flattening its central surface and altering how light focuses on the retina. This temporary reshaping allows for clear vision during the day without glasses or contact lenses, and is believed to reduce the stimulus for eye elongation.
Another strategy involves specialized multifocal contact lenses designed for myopia control. Unlike standard lenses that focus peripheral light behind the retina, these lenses are designed to focus peripheral light rays in front of the retina. This peripheral myopic defocus is thought to act as a “slow down” signal for eye growth, reducing myopia progression. Increased outdoor time has also been associated with a reduced risk of myopia progression.
Emerging and Experimental Treatments
Research continues to explore new avenues for preventing and treating myopia, leading to several emerging and experimental treatment options. These approaches are often still under investigation or not yet widely adopted as standard care. Scientists are exploring gene therapy and molecular treatments that aim to address the underlying causes of myopia at a genetic or cellular level. While promising, these complex areas of study require extensive research and clinical trials before becoming broadly available.
Newer spectacle lenses, such as those incorporating Defocus Incorporated Multiple Segments (DIMS) technology, are also being developed and utilized in some regions. These lenses create a myopic defocus in the peripheral visual field, similar to some myopia control contact lenses, to signal the eye to slow its growth. Smart glasses and wearable technologies are also being investigated for their potential to deliver light therapy or integrate vision training programs, though their long-term efficacy and widespread application are still being evaluated. These developments highlight the dynamic nature of myopia management and the continuous effort to find more effective interventions.