One interesting topic I learned working at the eye clinic recently was myopia
control. To understand this, first let’s look at what myopia is and its
complications.
Myopia is another term for near-sightedness, an inability to see things at a distance. In essence, myopia occurs because the eyeball is too long, so the focal point (where light rays meet) in the retina (the back of the eye) does not actually meet at the retina like it’s supposed to. Instead, the focal point is in front of the retina.
Myopia is another term for near-sightedness, an inability to see things at a distance. In essence, myopia occurs because the eyeball is too long, so the focal point (where light rays meet) in the retina (the back of the eye) does not actually meet at the retina like it’s supposed to. Instead, the focal point is in front of the retina.
Myopia, like most conditions, has both genetic and
environmental causes. For example, spending more time outdoors can decrease the
chances of myopia while having two parents with myopia increases one’s chances (Smith
& Walline, 2015). Myopia is very
common and the rates are increasing – approximately 1/3 of people in the US
have it and some eastern Asian countries demonstrate 90% occurrence (Smith
& Walline, 2015).
Myopia is a concern because it is associated with complications that further impact vision like macular degeneration, cataracts, glaucoma, retinal holes and tears, and retinal detachments (MyopiaControl.org, 2017). Considering the incidence, prevalence, and risks, studies have started looking at prevention.
The most effective ways to decrease myopia progression are drugs like atropine or pirenzepine, soft bifocal contact lenses, or orthokeratology contact lenses (they slow progression by 50-77% depending on the treatment) (Smith & Walline, 2015). The mechanism for how atropine or pirenzepine slow myopia is unknown, but they are both anti-muscarinic eye drops that reduce eye growth (Smith & Walline, 2015). Pirenzepine is more effective than atropine, however, because atropine comes with side effects like light sensitivity and blurry near vision due to pupil dilation (Smith & Walline, 2015)
Myopia is a concern because it is associated with complications that further impact vision like macular degeneration, cataracts, glaucoma, retinal holes and tears, and retinal detachments (MyopiaControl.org, 2017). Considering the incidence, prevalence, and risks, studies have started looking at prevention.
The most effective ways to decrease myopia progression are drugs like atropine or pirenzepine, soft bifocal contact lenses, or orthokeratology contact lenses (they slow progression by 50-77% depending on the treatment) (Smith & Walline, 2015). The mechanism for how atropine or pirenzepine slow myopia is unknown, but they are both anti-muscarinic eye drops that reduce eye growth (Smith & Walline, 2015). Pirenzepine is more effective than atropine, however, because atropine comes with side effects like light sensitivity and blurry near vision due to pupil dilation (Smith & Walline, 2015)
Soft bifocal contact lenses are generally used by people who
have trouble seeing at distance and near, but they have been shown to slow eye
growth by creating myopic defocus (Smith & Walline, 2015).
Orthokeratology contact lenses are worn at night – they flatten
the cornea, allowing the patient to not require corrective lenses during the
day while also slowing myopia progression. It is thought they work by inducing
myopic blur, signaling the eye to grow less (Smith & Walline, 2015).
Despite success rates, none of these treatments are approved by the FDA in the US for myopic control (Smith & Walline, 2015). Should we fast track these treatments for the beneficience of our patients?
Despite success rates, none of these treatments are approved by the FDA in the US for myopic control (Smith & Walline, 2015). Should we fast track these treatments for the beneficience of our patients?
MyopiaControl.org.
(2017). MYOPIA CONTROL FAQ. Retrieved November 9, 2019, from
http://www.myopiacontrol.org/myopia-faq/.
Smith, M. J., & Walline, J. J. (2015). Controlling myopia progression in children and adolescents. Adolescent health, medicine and therapeutics, 6, 133–140. doi:10.2147/AHMT.S55834
Smith, M. J., & Walline, J. J. (2015). Controlling myopia progression in children and adolescents. Adolescent health, medicine and therapeutics, 6, 133–140. doi:10.2147/AHMT.S55834
I have myopia and every time I go into my yearly checkup my vision continues to get worse! So, these treatments sound intriguing to me, especially learning that myopia is associated with more complications down the road. However, because the mechanism for how atropine or pirenzepine slow myopia is unknown I think that should be researched more before it can be passed by FDA and given as a treatment.
ReplyDeleteWhat sparked an interest was that myopia is found to have a 90% occurrence in eastern Asian countries. I looked more into this and a study done at UCLA researched prevalence of myopia between newly immigrated students of different ethnicities in the U.S. (Voo et al., 1998). They found that women have a significantly higher prevalence of myopia than males and Asians have a significantly higher prevalence than Hispanics (Voo et al., 1998). This may explain why my eyes are terrible!
According to the Smith & Walline study, all methods were found to be effective on children and adolescents (2015). Are there any studies done on adults and do you think these methods would be beneficial for adults? Also, if these methods are shown to just slow the progression of myopia are there studies that show if these potential treatments can completely prevent later complications and the need for surgery, such as LASIK, in the long run?
References
Smith, M. J., & Walline, J. J. (2015). Controlling myopia progression in children and adolescents. Adolescent health, medicine and therapeutics, 6, 133–140. doi:10.2147/AHMT.S55834
Voo I, Lee DA, Oelrich FO. Prevalences of ocular conditions among Hispanic, white, Asian, and black immigrant students examined by the UCLA Mobile Eye Clinic. J Am Optom Assoc. 1998;69(4):255–261.