Contact Lens Update

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Dr Paul Gifford consults with the contact lens industry on development of contact lens designs and their implementation into clinical practice. He is a partner in private practice conducting clinical research on use of contact lenses and orthokeratology to control progression of myopia, and holds an Adjunct Senior Lecturer position at the School of Optometry and Vision Science, University of New South Wales, Sydney.

In the Treatise of Human Nature, published in 1739, David Hume observed that the more distant something is in time and space, the less we care about it. Although written in past times, the topic of myopia control taps into this interesting human paradox, as the failure to take effective action now does not present consequence until considerable time into the future.

To investigate how sizeable this problem might become, researchers from the Brien Holden Vision Institute recently published a systematic review and meta-analysis on global prevalence of myopia and high myopia.¹ Filtering through 4288 research articles on prevalence of refractive error or myopia the authors were left with 145 valid articles to form their analysis. Global prevalence of myopia was reported as 22.9% in 2000 rising to 28.3% in 2010. When projected forward to 2050 the authors predict that, at current trends, global prevalence of myopia will become 49.8%, with 9.8% of the global population being highly myopic (-6.00D or more). Even if we consider this data to be an over-estimate, it is safe to conclude that the prevalence of myopia is growing at an alarming rate.

As eye care practitioners it is our lifeblood to correct myopia, but the problem is not the correcting but the long term health implications of myopia, particularly when we take extending longevity of life into consideration. There is a 4x likelihood of developing retinal detachment from as little as -0.75D through -3.00D compared to the emmetrope, with the odds increasing to 10x once past -3.00D.² Myopia increases risk of developing glaucoma, with an odds ratio of 1.65 for up to -3.00D increasing to 2.46 when greater than -3.00D,³ and posterior sub capsular cataract.⁴ Myopia from -2.00D up to -4.00D brings a 3 times risk of posterior sub capsular cataract, increasing to 5 times for myopia from -4.00D up to -6.00D and 12 times for -6.00 and greater.⁵ But by far the most worrying, is myopic maculopathy, which stands out as the only disease amongst the top five causes of blindness that remains entirely untreatable.⁶ The Blue Mountains Study reported 25.3% prevalence of myopic maculopathy in those with greater than -5.00D of myopia, increasing to more than 52.4% once beyond -9.00D.⁷

The good news is that slowing the progression of myopia from the onset would have a dramatic effect on reducing incidence of high myopia in later life, with 33% myopia control effect leading to a reduction of 73% in the frequency of myopia greater than -5.00D, while a 50% myopia control effect would reduce frequency to over 90%.⁸ Fortunately, we have multiple treatment options available to provide such an effect. Studies investigating multifocal contact lens designs report 34-50% reduction in myopia progression,^9–11 while orthokeratology (OK) studies demonstrating a consistent 50% myopia controlling effect.¹² For those that can prescribe pharmaceuticals, atropine has demonstrated up to 72% reduction in myopia progression,^13–15 though there is a lack of consensus on optimum concentrations and there appears to be a rebound effect following cessation of treatment.^16–20

Taking all of this evidence into consideration, optometry is perfectly placed to slow the myopia epidemic. Its retail practice structure promotes readily available access to the public and lines of communication that are less available to many other health professions. We are able to push information about the myopia problem through our websites and marketing literature, while the typical consultation process lends itself to communicating the valuable message that spending more time outside while reducing screen time can help slow both the onset and progression of myopia.²¹ Yet, a recent globally conducted practitioner questionnaire revealed that, despite there being high practitioner concern about the frequency of paediatric myopia, particularly across Asia, in 47.8% of cases single vision spectacles were prescribed for progressing or young myopes, followed by single vision contact lenses in 15.2% of cases.²² Factors for preventing the prescription of a myopia control approach were listed in decreasing order as: uneconomical; inadequate information; unpredictable; safety concerns; ineffective; risk vs benefit; and that it would require additional chair time.

We currently lack sufficient information to debunk some of these concerns, as it will take time to fully understand the safety aspects of actively attempting to control myopia compared to traditional methods for correcting refraction. Likewise, the true picture of risk vs. benefit. Though we can use current data to demonstrate higher risk of developing sight-threatening disease over a lifetime of high myopia^2–7 compared to the risk of contracting microbial keratitis from wearing a contact lens²³ to limit progression of myopia to less risky levels. However, a basic literature search will reveal a plethora of information revealing that myopia control is effective,^9–15 so failure for this to be observed in the survey conducted by Wolffsohn et al. can only indicate that this information is not being adequately translated to clinicians. A further barrier is lack of accepted frameworks and clinical protocols for incorporating myopia control into practice.

On this backdrop, the recent convening of practitioners and researchers by the United States FDA to initiate discussions for developing FDA approval protocols for myopia control is long overdue, as despite the powers of FDA approval being limited to the United States, products that are approved generally give confidence in their use across the world. However, despite this welcome initiative, even if the planets perfectly align to facilitate speedy progression, we are unlikely to see the first FDA-approved myopia control device for a few years, which in the interim tosses the ball back into the practitioner’s court. While on current trends we may prefer to take the tried and tested option of single vision correction, the evidence for slowing progression of myopia using existing contact lens options suggests that we should be more proactive in the management of myopia. This then raises the question of confidence in fitting children with contact lenses.

Wolffsohn et al. found that contact lens myopia control options were only considered appropriate for older children, with OK and multifocal soft contact lenses considered as appropriate from an average 8.8 years and 8.9 years respectively.²² The same survey reported -2.00D of myopia as the stage when myopia control devices would be considered. With higher rates of progression occurring in the early stages of myopia,²⁴ it could be argued that starting a myopia control strategy early, rather than waiting until -2.00, is more likely to yield greater likelihood in reducing high myopia in adulthood. The reducing age of myopia onset may cause consideration for fitting younger children,²⁵ but current evidence suggests that we can be confident in fitting soft, rigid and orthokeratology lenses from eight years of age.^26–29 Fitting pre-teen children aged 8-12 years with contact lenses does require 10-15 minutes more chair time than teenagers, mainly on contact lens application and removal, but otherwise they have similar outcomes.³⁰ Pre-teens also report contact lens wear to improve their physical appearance, athletic competence and social acceptance compared to glasses.²⁷

Returning to my opening line, we must keep all of these factors in mind as we consider how our actions managing myopic children today will impact their lives in the future. The U.S. FDA initiating discussions about regulating myopia control products indicates that in the not too distant future myopia management rather than correction will become the norm, and the steadily growing number of myopia control articles in clinical journals shows that some are already on board. So if you are not already managing myopia the question boils down to when, rather than if, you will join them, and ultimately amid growing evidence, how long you are prepared to wait.

REFERENCES:

1. Holden BA, Fricke TR, Wilson DA, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmol 2016;123: 1036-42.
2. The Eye Disease Case-Control Study Group. Risk factors for idiopathic rhegmatogenous retinal detachment. Am J Epidemiol 1993;137: 749-57.
3. Marcus MW, De Vries MM, Junoy Montolio FG, et al. Myopia as a risk factor for open-angle glaucoma: A systematic review and meta-analysis. Ophthalmol 2011;118: 1989-94.
4. Lim R, Mitchell P, Cumming P. Refractive associations with cataract: the Blue Mountains Eye Study. Invest Ophthalmol Vis Sci 1999;40: 3021-26.
5. Chang MA, Congdon NG, Bykhovskaya I, et al. The association between myopia and various subtypes of lens opacity: Salisbury Eye Evaluation project. Ophthalmol 2005;112: 1395-1401.
6. Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res 2012;31: 622-60.
7. Vongphanit J, Mitchell P, Wang JJ. Prevalence and progression of myopic retinopathy in an older population. Ophthalmol 2002;109: 704-11.
8. Brennan NA. Predicted reduction in high myopia for various degrees of myopia control. Contact Lens Ant Eye 2012;35 (Supp.): e14-15.
9. Gwiazda J, Hyman L, Hussein M, et al. A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest Ophthalmol Vis Sci 2003;44: 1492-1500.
10. Sankaridurg P, Holden B, Smith E, et al. Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results. Invest Ophthalmol Vis Sci 2011;52: 9362-7.
11. Aller T, Liu M, Wildsoet C. Myopia control with bifocal contact lenses : A randomized clinical trial. Optom Vis Sci 2016: 93.
12. Sun Y, Xu F, Zhang T, et al. Orthokeratology to control myopia progression: A Meta-Analysis. PLoS One 2015;10: e0124535.
13. Chia A, Chua WH, Cheung YB, et al. Atropine for the treatment of childhood myopia: Safety and efficacy of 0.5%, 0.1%, and 0.01% doses (Atropine for the Treatment of Myopia 2). Ophthalmol 2012;119: 347-54.
14. Shih YF, Hsiao CK, Chen CJ, et al. An intervention trial on efficacy of atropine and multi-focal glasses in controlling myopic progression. Acta Ophthalmol Scand 2001;79: 233-6.
15. Chua WH, Balakrishnan V, Chan YH, et al. Atropine for the treatment of childhood myopia. Ophthalmol 2006;113: 2285-91.
16. Tan DTH, Lam DS, Chua WH, et al. One-year multicenter, double-masked, placebo-controlled, parallel safety and efficacy study of 2% pirenzepine ophthalmic gel in children with myopia. Ophthalmol 2005;112: 84-91.
17. Yang Z, Lan W, Ge J, et al. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Ophthalmic Physiol Opt 2009;29: 41-8.
18. Tong L, Huang XL, Koh ALT, et al. Atropine for the treatment of childhood myopia: effect on myopia progression after cessation of atropine. Ophthalmol 2009;116: 572-9.
19. Cheng D, Woo GC, Drobe B, et al. Effect of bifocal and prismatic bifocal spectacles on myopia progression in children: three-year results of a randomized clinical trial. JAMA Ophthalmol 2014;132: 258-64.
20. 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. Ophthalmol 2016;123: 391-9.
21. Rose K, Morgan IG, Ip J,et al. Outdoor activity reduces the prevalence of myopia in children. Ophthalmol 2008;115: 1279-85.
22. Wolffsohn JS, Calossi A, Cho P, et al. Global trends in myopia management attitudes and strategies in clinical practice. Contact Lens Ant Eye 2016;39: 106-16.
23. Stapleton F, Keay L, Edwards K, et al. The incidence of contact lens-related microbial keratitis in Australia. Ophthalmol 2008;115: 1655-62.
24. Donovan L, Sankaridurg P, Ho A, et al. Myopia progression rates in urban children wearing single-vision spectacles. Optom Vis Sci 2012;89: 27-32.
25. McCullough SJ, O’Donoghue L, Saunders KJ. Six year refractive change among white children and young adults: evidence for significant increase in myopia among white UK children. PLoS One 2016;11: 1-19.
26. Walline JJ, Jones L, Mutti DO, et al. A randomized trial of the effects of rigid contact lenses on myopia progression. Arch Ophthalmol 2004;122: 1760-6.
27. Walline JJ, Jones LA, Sinnott L, et al. A randomized trial of the effect of soft contact lenses on myopia progression in children. Invest Ophthalmol Vis Sci 2008;49: 4702-6.
28. Walline JJ, Long S, Zadnik K. Daily disposable contact lens wear in myopic children. Optom Vis Sci 2004;81: 254-8.
29. Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Curr Eye Res 2005;30: 71–80.
30. Walline JJ, Jones L, Rah MJ, et al. Contact lenses in pediatrics (CLIP) study: chair time and ocular health. Optom Vis Sci 2007;84: 896-902.