Meenakshi Jadli, D. Optometry
Fellow Optometrist, Dr. Shroff’s Charity Eye Hospital, Delhi, India
Myopia (near-sightedness) is a leading cause of refractive error for distance. The main cause of myopia is eyeball elongation due to which light coming from the infinity fall in front of the retina thereby making the image appear blurred.(1) An annual increment in the degree/magnitude of myopia (-0.50D is mild, -1.00 D is moderate, and more than -1.00D is severe) but it also depends on the age. The annual myopia progression observed in early-onset cases (i.e., <12 years of age) is reported to be significantly higher in comparison to late onset cases (≥12 years of age). Myopia control is very important as severe myopia can cause Retinal detachment, cataract, glaucoma, macular degeneration, and many other threatening ocular diseases.(1) Myopia progression can be controlled by some Myopia treatments like Orthokeratology and Atropine. Ortho k lenses are centrally flat, so they exert pressure on the central corneal surface which helps in decreasing the sagittal height of the eyeball and eliminate the refractive error.(2)
(Pic courtesy – Shady Grove Eye and vision care, https://www.youreyesite.com/what-is-myopia-can-it-be-cured/)
Orthokeratology or ortho k lenses are night wear contact lenses. They are non-surgical, topographical lenses that eliminate the refractive error by reducing the sagittal height and shortening the axial length of the eyeball.(2) Ortho k lenses are based on reverse geometry with high DK (oxygen permeability) that means they are centrally flat and peripherally steep.(2) Ortho k lenses are centrally flat so when you wear ortho k lenses while sleeping they exert pressure on the corneal surface to flatten it by pushing the epithelial cells towards the periphery and after waking up when you remove the ortho k lens your cornea get reshaped and you see a clear whole day without the use of any optical aids.
((Pic courtesy – Cao Thang International Eye Hospital, http://cteyehospital.com/ortho-k/)
Atropine sulfate is an antimuscarinic agent used as a cycloplegic and mydriatic and considered to be one of the most effective therapies for myopia control.(3) The mechanism of atropine in myopia control is still not properly known. But there are some theories about it; one is that atropine blocks the accommodation which reduces the effect of accommodation on the myopia progression. Some researchers say that atropine affects dopamine (a neurotransmitter releases from the brain to transmit the messages or signals from body to brain] which influence retinal signal that controls the growth of the eye.(4)
Atropine is available in different concentrations 0.01%, 0.50% and 1.00%. But the most effective concentration in myopia control is low dose atropine (0.01%) (3) because it has lesser side effects like photophobia, eye irritation, fast heart rate etc.
Combined use of Atropine and Ortho k lenses
Ortho k lenses and Atropine are two of the most effective therapies for myopia control.(5) Nowadays this therapy is being used a lot in controlling myopia because of its efficiency in myopia control and lesser or no side effects. This is a night therapy, firstly put one drop of atropine in each eye at least 5 minutes before inserting the ortho k lenses and go to sleep.(6, 7) While sleeping atropine and ortho k lens start their work to eliminate the refractive error and after waking up put some drop of artificial tears in each eye to avoid corneal abrasion and remove the ortho k lens. Then you can see a clear whole day without the use of any optical aids. This treatment is getting popularity among the world for myopia control.
- Bremond-Gignac D. Myopie de l’enfant (Myopia in children). Med Sci (Paris). 2020 Aug-Sep;36(8-9):763-768. French. doi: 10.1051/medsci/2020131. Epub 2020 Aug 21.
- Nti AN, Berntsen DA. Optical changes and visual performance with orthokeratology. Clin Exp Optom. 2020 Jan;103(1):44-54. doi: 10.1111/cxo.12947. Epub 2019 Aug 4.
- Chia A, Lu QS, Tan D. Five-Year Clinical Trial on Atropine for the Treatment of Myopia 2: Myopia Control with Atropine 0.01% Eyedrops. Ophthalmology. 2016 Feb;123(2):391-399. doi: 10.1016/j.ophtha.2015.07.004. Epub 2015 Aug 11. PMID: 26271839.
- Thomson K, Kelly T, Karouta C, Morgan I, Ashby R. Insights into the mechanism by which atropine inhibits myopia: evidence against cholinergic hyperactivity and modulation of dopamine release. Br J Pharmacol. 2021 Nov;178(22):4501-4517. doi: 10.1111/bph.15629. Epub 2021 Oct 10. PMID: 34302355.
- Kinoshita N, Konno Y, Hamada N, Kanda Y, Shimmura-Tomita M, Kakehashi A. Additive effects of orthokeratology and atropine 0.01% ophthalmic solution in slowing axial elongation in children with myopia: first year results. Jpn J Ophthalmol. 2018 Sep;62(5):544-553. doi: 10.1007/s10384-018-0608-3. Epub 2018 Jul 4.
- Qi Tan , Alex Lk Ng , Bonnie Nk Choy , George Pm Cheng , Victor Cp Woo , Pauline Cho One-year results of 0.01% atropine with orthokeratology (AOK) study: a randomised clinical trial Ophthalmic Physiol Opt. 2020 Sep;40(5):557-566.Epub 2020 Aug 10.
- Kinoshita N, Konno Y, Hamada N, Kanda Y, Shimmura-Tomita M, Kaburaki T, Kakehashi A. Efficacy of combined orthokeratology and 0.01% atropine solution for slowing axial elongation in children with myopia: a 2-year randomised trial. Sci Rep. 2020 Jul 29;10(1):12750. doi: 10.1038/s41598-020-69710-8. PMID: 32728111; PMCID: PMC7391648.