What causes nearsightedness? Genes are only part of the answer and the other culprit is environmental to include near point stress and time spent outdoors. Although, several studies have shown that a child with one or both parents nearsighted increases the risk of myopia. Generally, the environment that created myopia in the parent is the same for the child. Epidemiological studies have shown that the U.S. is 41.6% myopic whereas Asians are 60 to 80% myopic.
Myopia (nearsightedness) is a condition that is associated with blurred vision at distance although vision at near is clear. Halting the progression of myopia could impact the lives of about 42 million children in the U.S. Once myopia begins in children 8 to 13 years old, it usually gets worse each year. As the myopia increases so does the length of the eye developing retinal stretching. Myopia not only causes vision difficulties for seeing but also causes an increase in sight threatening eye diseases such as myopic macular degeneration, cataract, glaucoma, retinal holes and tears, and retinal detachments as the retina stretches from the prescription increases. Davis EyeCare is concern about the potential risk and is recommending that you consider an intervention to help limit the progression of your child’s increasing myopia as a preventative program.
At Davis EyeCare we have myopia prevention options that will limit the progression of myopia as well as develop a program that you are most comfortable with.
Therapeutic Intervention— Low-dose Atropine
The effectiveness of Atropine for myopia control is higher than any other form of treatment currently available. Recent research has proven that low-dose Atropine is effective at reducing the rate of myopia progression by approximately 50%.. However, as the concentration is reduced the effectiveness of myopia stabilization is reduced. Lower concentrations have a much less likelihood of side effects than at the full concentration.
Patient and parent philosophies are also taken into account, and may prefer to avoid long-term medication use. While atropine has been a popular myopia control method for years, optometrists are often hesitant to recommend it due to concerns about side effects. The current literature, with the longest follow up of five years, reports no long-term side effects on accommodation or retinal function associated with the use of atropine. Clinically, we have yet to see a case with any significant complication due to therapy with low-dose atropine. Low-dose atropine may be a useful option for cases that are outside of the FDA-approved parameters for corneal reshaping, for those who are not appropriate multifocal contact lens candidates and in combination therapy. A thorough discussion of the benefits and risks of low-dose atropine can help patients and parents develop a comfort level with this option.
Soft Lens Multifocal— Peripheral Defocus
The use of specially designed soft multifocal contact lenses has been shown in numerous studies to significantly limit the progression of myopia when compared to traditional single vision contact lenses or glasses. The effectiveness of these multifocal therapeutic contact lenses has been reported to reduce the rate of myopic progression by 40% to 50% depending on studies cited.
When fitting children in soft contact lenses, we are most comfortable with the single-use lens modality. Center-distance designs are our first choice, considering the optical effect is closest to mimicking the optics of a post corneal reshaping cornea.
The theory of why they reduce the progression of nearsightedness is based on a broadly accepted theory of nearsightedness development which is called “peripheral hyperopic defocus”. By focusing light in front of the peripheral retina, these lenses inhibit elongation growth of the eye which results in progressive nearsightedness.
Research shows myopic defocus in the peripheral retina can be a powerful stimulus to slow myopic progression and is the leading theory on the effectiveness of corneal reshaping and multifocal contact lenses.
Your doctor at Davis EyeCare will tailor a plan along with you and your child to find the appropriate design and parameters of myopic stabilization multifocal soft contact lenses that will have the highest probability of controlling the progression of your child’s myopia. These lenses need to be worn for minimum hours daily in order to exert their effect. The specific wearing schedule will be discussed with you by your doctor. These contact lenses in addition to controlling myopic progression will correct your child’s vision at all distances, will be comfortable to wear for the full wearing schedule and will be as healthy to wear as traditional contact lenses. As part of the therapeutic program your doctor will monitor your child’s vision and refractive status, eye health response and all elements that contribute to an optimal outcome during the course of therapy.
Corneal Reshaping Technique
Corneal Reshaping Therapy (CRT), also known as accelerated orthokeratology, is a non-surgical treatment method to reduce nearsightedness (myopia) and/or astigmatism. The process involves the use of specialized “reverse geometry” gas permeable contact lenses that are specifically designed to alter the surface (curvature) of the cornea. Following removal of the contact lenses visual acuity improves beyond pre-treatment levels and will most often improve vision to normal eyesight without the use of glasses. The CRT contact lenses will need to be worn as a “retainer” for limited periods of time (typically while sleeping at night) in order to maintain the therapeutic effect. The results of CRT will vary to some degree from patient to patient, but are typically related to the degree of refractive error (i.e. prescription levels). Although results are typically excellent for appropriate candidates, results cannot be guaranteed due to individual cornea and eye response variability.
Research suggests this treatment option slows myopia progression, on average, by 45% with the added benefit of not needing an optical correction during the day. However, proceed with caution with children who are outside of the FDA-approved parameters. For reference, FDA-approved for up to -6.00D of myopia and -1.75D of astigmatism. Despite the excellent safety profile of corneal reshaping lenses, some parents are not comfortable with the concept of overnight contact lens wear. These patients may do better with one of the other treatment programs.
The duration of effect and the period of time between contact lens wear that retains clear uncorrected vision will be patient dependent and should be discussed with your doctor. Vision while wearing CRT lenses is typically 20/20 with lenses on from day one throughout CRT treatment. CRT lenses will need to be replaced annually and will be modified in parameters based on the results of your comprehensive eye health and CRT examination at that time. Corneal Reshaping Therapy has been shown in numerous studies to also control/stabilize the rate of progression of myopia.