GOS statistics indicate that about 1.5 million children in the UK wear a refractive correction and yet only around 8% of contact lens fits in the UK are to teenagers and 2% to children. This large international survey reveals that the proportion of young people who are fitted with contact lenses in the UK is lower than in most other countries and raises the question: are we under-prescribing contact lenses to children and teenagers? To address this question we will first look at why we fit adults with contact lenses and then ask whether these reasons apply more or less strongly to young people.
Why do we fit adults with contact lenses?
Research has established that cosmesis is the major reason why adults are motivated to wear contact lenses.2 This is supported by another study, which reveals that the major two motivations are concerns about appearance and convenience, with sports and better vision also rating highly.3 Many people spend more time involved in sporting activities during their school years than in later life, so this reason would seem to apply to young people at least as much as to older people. Since cosmesis is the major reason why adults consider contact lenses, the importance of cosmesis for children will now be considered.
Cosmesis: an understatement for changing some children’s livesWhen we think about young people and cosmesis we probably think about the teenage years, but it seems likely that children are more self-conscious than teenagers. Even today, 16–40% of children in UK schools experience bullying4 and the effects persist into adult life.5 A large study of 8.5 year-olds shows that spectacle wearers are 35% more likely to be victims of bullying.6 Research has shown that fitting children aged 8–11 years with contact lenses improves their physical appearance, athletic competence, and most importantly their social acceptance.7
In high refractive errors there are clear advantages to contact lenses over spectacles, such as larger retinal image sizes in myopia and a more normal field of view in hypermetropia. However, perhaps the most important indication for contact lenses is anisometropia, which affects 13.5% of the European population. The potential advantages of contact lenses in anisometropia were highlighted by Keith Edwards in 1979,9 and the optical benefits were demonstrated experimentally by subsequent authors.10-13 Specifically, the research indicates that for both refractive and axial anisometropia, contact lenses minimise aniseikonia and, therefore, maximise the potential for normal binocular vision. This is important not just to optimise binocularity in anisometropia but also because of the need to encourage cortical use of the monocular input from each eye. The importance of optical correction in treating amblyopia has been known for over years14 and recently it has been shown that amblyopic children improve on average by 2.5 lines just from wearing spectacles and 22% of cases need no patching, just spectacles.15 If this much improvement can be brought about with spectacles then the reduced aniseikonia and potential for better fusion with contact lenses means that a more marked treatment effect is likely with contact lenses.
The benefit of using contact lenses in anisometropia does not just relate to the acuity now, but also to the potential for life-long best- corrected acuity improvements. The notion of a sensitive period for the treatment of amblyopia is an oversimplification. For orthotropic anisometropic amblyopia a literature review indicates that the condition can be treated, at any age.16 So, for patients with orthotropic anisometropic amblyopia, especially if they are not wearing an appropriate refractive correction for their amblyopic eye, there is a real possibility that contact lenses will bring about an improvement over time in the best-corrected acuity in the affected eye. In other words, contact lenses may do more than just correct the refractive error; they may reduce the amblyopia. Although such effects might be seen at any age, generally speaking, the younger that correction is prescribed, the better – assuming that the criteria for safe contact lens wear are met.
There is a pressing need for randomised controlled trials to investigate the effect of contact lenses on visual acuity in anisometropia. However, what we know about aniseikonia and the effect of refractive correction on amblyopia mean that contact lenses are the preferred mode of optical correction for patients with this condition. This is quite an easy discussion to have since patients can readily visualise that it is not natural to correct their refractive error with spectacles where the two lenses are so very different.
Optometrists have for many years been involved in the treatment of amblyopia, but their role in myopia has, until recently, largely been confined to correction rather than treatment. Recent research has improved our understanding of myopia and led to contact lens based interventions for slowing myopia progression. There have been several excellent reviews of this topic and it will only be briefly summarised here.17–19 Myopia is the commonest ocular abnormality and its prevalence is increasing markedly.18 Myopia increases the risk of several ocular pathologies and interventions that reduce the ultimate level of myopia will reduce the risk of these pathologies.18 Brennan has shown that reducing the rate of myopia progression by 50% would lead to a reduction in the frequency of high myopia by over 90%.20
The determination of refractive error during an eye exam is driven by a consideration of the situation at the fovea. For most emmetropic patients this is not an issue because when the image shell is in focus at the fovea then it is also likely to be in focus, or close to in focus, in the peripheral retina (Figure 1: Schematic diagram illustrating the possible role of relative peripheral hyperopic defocus (RPHD) in the aetiology). For myopic children the situation is different and the image shell in the periphery typically has relative hyperopic defocus (the image shell is behind the retina). This seems to occur even before the child becomes myopic the peripheral retina has hyperopic defocus and yet the fovea is in focus so no significant refractive error would be detected during a refraction (see second panel of Figure 1). It is believed that the peripheral retina dominates in the signals that drive eye growth.19 This relative peripheral hyperopic defocus (RPHD) drives eye growth and axial length elongates to bring the peripheral retina in focus, leading to myopic defocus at the fovea (third panel of Figure 1). The optometrist’s duty is to help the child see distant objects clearly so we prescribe a concave lens that will bring the image shell at the fovea into focus, but this restores the RPHD, possibly driving further myopic changes.
This raises the possibility that optical interventions that correct RPHD may reduce myopia progression. Several research groups and manufacturers have developed or are developing special designs of soft contact lenses and the initial results show a promising ability to slow myopia progression.21–24 These designs are not yet commercially available in the UK, but there are two currently available modalities that seem to correct RPHD and show encouraging signs of slowing myopia. Orthokeratology is one of these modalities.25,26 Several studies (see Figure 2: Graph illustrating the percentage reduction in axial length growth in myopia (compared with control group in each study) Pink bars illustrate predominantly Caucasian population; blue bars indicate predominantly Asian population. CCS, case control series; RCT, randomised controlled trial) show a reduction in axial length elongation (a proxy for myopia progression) with orthokeratology.27–32 Many patients wear orthokeratology safely, but there have been concerns over the risk of microbial keratitis,33 which probably has a similar prevalence to that in other overnight contact lens modalities.34
Multifocal (MF) contact lenses of a centre- distance design also reduce RPHD35-37 and slow myopia progression.38,39 In Figure 3 the effects of MF contact lenses on slowing myopia progression are compared with three studies of special designs of myopia control (MC) soft contact lenses.21-23 The treatment effect seems greatest in cases where there is an esophoria (SOP) at near, indicating that the mechanism may be more complex than just RPHD.40 Figure 3: Graph illustrating the percentage reduction in myopia progression (compared with control group in each study). In the Lam et al study an improved treatment effect was found in participants who wore the lenses for more than five hours a day, as illustrated with the arrow. Pink bars illustrate predominantly Caucasian population; blue bars indicate predominantly Asian population. CCS, case control series; RCT, randomised controlled trial; MF, multifocal; SCL, soft contact lenses; SOP, esophoria; MC, myopia control)
- Centre-distance lenses should be used. The two lens types that seem to be used most often are the CooperVision Biofinity Multifocal (centre-distance lens to each eye) and Acuvue Oasys for Presbyopia
- Test the patient for near esophoria (with myopic correction; for example, using the Maddox wing test). If present then try to use an add that eliminates the esophoria
- With the Biofinity lens, a +2.00D add seems to be used most often, although a higher add might be more effective if it does not adversely affect the distance vision
- The lenses are usually very well tolerated and children do not report any distance blurring, but this should be checked and the add adjusted if necessary
- The procedure is remarkably straightforward for most children
Other reasons for fitting children with contact lenses
In addition to the factors discussed above, there are other less common indications to fit children with contact lenses. Some patients with dyslexia or migraine benefit from precision tinted lenses44 and the cosmetic issues associated with these mean that some cases prefer precision tinted contact lenses. Some orthoptic conditions can be managed with contact lenses.45
Maximising safety and success when fitting children with contact lenses
- When children need glasses, explain that contact lenses are a viable option
- Tell the child that they are not going to wear a lens today but they can have a look at one
- Place a trial lens on the child’s finger and let them touch it
- Ask the child what it is mostly made of. They might guess plastic or rubber. Eventually, tell them that it is mostly made of water
- Ask the child if they have ever had a drop of rain go in their eye. Highlight that it would not have hurt but would have felt cold and wet and made them blink
- Explain that the contact lens, which is mostly water, will feel cold, wet, make them blink but should never hurt
- Educate the child and parent that if a lens hurts it is a warning sign and requires the lens to be removed and if the problem persists the ECP should be consulted
- Tell the child that since you have handled the trial lens without washing your hands then it must not be worn and should be thrown away. Let them watch you throw it away
For all contact lens patients, the concern is that no matter how well they behave in our consulting room they may have unsafe habits at home. Here, the situation with children and teenagers is potentially better than with older patients if ECPs can engage parents in monitoring for compliance at home.
It has been demonstrated in this article that the main reasons why ECPs fit adults with contact lenses apply more strongly to children. Children, typically, aged eight to 12 years, can benefit just as much from contact lenses as teenagers and can be fitted with high success rates. ECPs should discuss contact lenses as an option in any person needing a refractive correction and they should be recommended as the optimum mode of correction for people with anisometropia. Myopia control is likely to become a major part of clinical practice in the near future52 and today currently available centre distance multifocal contact lenses can slow progression by significant amounts. ECPs need to take an active role in encouraging compliance and should enlist the help of parents in this endeavour.
About the author
Professor Bruce Evans is director of research at the Institute of Optometry and a visiting professor to City University London and London South Bank University. He spends most of his week working as a community optometrist where he has a special interest in children's vision and contact lenses.
- Efron N, Morgan PB, Woods CA. Survey of Contact Lens Prescribing to Infants, Children, and Teenagers. Optom Vis Sci 2011; 88(4):461-468
- Gupta N, Naroo SA. Factors influencing patient choice of refractive surgery or contact lenses and choice of centre. Cont Lens Anterior Eye 2006; 29(1):17-23
- Bowden T, Harknett A. What the patient wore, and why .. Cont Lens Anterior Eye 2006; 29(1):5-15
- Radford L, Corral S, Bassett C, et al. Child abuse and neglect in the UK today. 2011. London, NSPCC. 29-5-2014. Ref Type: Report
- Takizawa R, Maughan B, Arseneault L. Am J Psychiatry 2014; published online in advance
- Horwood J, Waylen A, Herrick D, et al. The Avon Longitudinal Study of Parents and Children Study Team. Common Visual Defects and Peer Victimization in Children. Investigative Ophthalmology Visual Science 2005; 46(4):1177-1181
- Walline JJ, Jones LA, Sinnott L, et al. Randomized trial of the effect of contact lens wear on self-perception in children. Optom Vis Sci 2009; 86(3):222-232
- Wolfram C, Hohn R, Kottler U, et al. Prevalence of refractive errors in the European adult population: the Gutenberg Health Study (GHS). Br J Ophthalmol 2014
- Edwards KH. The management of ametropic and anisometropic amblyopia with contact lenses. The Ophthalmic Optician 1979; December 8:925-929
- Winn B, Ackerley RG, Brown CA, et al. Reduced aniseikonia in axial anisometropia with contact lens correction. Ophthal Physiol Opt 1988; 8:341-344
- 11 Romano PE, von Noorden GK. Knapp's law and unilateral axial high myopia. 1970. Binocul Vis Strabismus Q 1999; 14(3):215-222
- Kramer P, Shippman S, Bennett G, et al. A study of aniseikonia and Knapp's law using a projection space eikonometer. Binocul Vis Strabismus Q 1999; 14(3):197-201
- Kitaguchi Y, Bessho K, Yamaguchi T, et al. In vivo measurements of cone photoreceptor spacing in myopic eyes from images obtained by an adaptive optics fundus camera. Jpn J Ophthalmol 2007; 51(6):456-461
- Gibson HW. Amblyopia. Textbook of Orthoptics. London: Hatton Press; 1955. 170-194
- Stewart CE, Moseley MJ, Fielder AR, Stephens DA, and the MOTAS cooperative. Refractive adaptation in amblyopia: quantification of effect and implications for practice. Br J Ophthalmol 2004; 88(12):1552-1556
- Evans BJW. Pickwell's Binocular Vision Anomalies. 5th ed. Oxford: Elsevier; 2007
- Charman WN, Radhakrishnan H. Peripheral refraction and the development of refractive error: a review. Ophthalmic Physiol Opt 2010; 30(4):321-338
- Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res 2012; 31(6):622-660
- 19 Smith EL. Prentice Award Lecture 2010: A case for peripheral optical treatment strategies for myopia. Optom Vis Sci 2011; 88(9):1029-1044
- Brennan NA. Predicted reduction in high myopia for various degrees of myopia control. Contact Lens & Anterior Eye 35S, e14-e15. 2012. Ref Type: Abstract
- Sankaridurg P, Holden B, Smith E, III, 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(13):9362-9367
- Anstice NS, Phillips JR. Effect of Dual-Focus Soft Contact Lens Wear on Axial Myopia Progression in Children. Ophthalmology 2011
- Lam CS, Tang WC, Tse DY, et al. Defocus Incorporated Soft Contact (DISC) lens slows myopia progression in Hong Kong Chinese schoolchildren: a 2-year randomised clinical trial. Br J Ophthalmol 2013
- Randomized clinical trial of myopia control in myopic schoolchildren using the defocus incorporated soft contact (DISC) lens. Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. 2010
- Ticak A, Walline JJ. Peripheral optics with bifocal soft and corneal reshaping contact lenses. Optom Vis Sci 2013; 90(1):3-8
- Kang P, Swarbrick H. Peripheral refraction in myopic children wearing orthokeratology and gas-permeable lenses. Optom Vis Sci 2011; 88(4):476-482
- 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(1):71-80
- Walline JJ, Jones LA, Sinnott LT. Corneal Reshaping and Myopia Progression. Br J Ophthalmol 2009
- Cho P, Cheung SW. Retardation of Myopia in Orthokeratology (ROMIO) Study: A 2-Year Randomized Clinical Trial. Invest Ophthalmol Vis Sci 2012; 53(11):7077-7085
- Santodomingo-Rubido J, Villa-Collar C, Gilmartin B, et al. Myopia control with orthokeratology contact lenses in Spain: refractive and biometric changes. Invest Ophthalmol Vis Sci 2012; 53(8):5060-5065
- Kakita T, Hiraoka T, Oshika T. Influence of overnight orthokeratology on axial elongation in childhood myopia. Invest Ophthalmol Vis Sci 2011; 52(5):2170-2174
- Hiraoka T, Kakita T, Okamoto F, Takahashi H, Oshika T. Long-term effect of overnight orthokeratology on axial length elongation in childhood myopia: a 5-year follow-up study. Invest Ophthalmol Vis Sci 2012; 53(7):3913-3919
- Swarbrick HA. Orthokeratology review and update. Clin Exp Optom 2006; 89(3):124-143
- Bullimore MA, Sinnott LT, Jones-Jordan LA. The risk of microbial keratitis with overnight corneal reshaping lenses. Optom Vis Sci 2013; 90(9):937-944
- Kang P, Fan Y, Oh K, et al. The effect of multifocal soft contact lenses on peripheral refraction. Optom Vis Sci 2013; 90(7):658-666
- Berntsen DA, Kramer CE. Peripheral defocus with spherical and multifocal soft contact lenses. Optom Vis Sci 2013; 90(11):1215-1224
- Rosen R, Jaeken B, Lindskoog PA, et al. Evaluating the peripheral optical effect of multifocal contact lenses. Ophthalmic Physiol Opt 2012; 32(6):527-534
- Aller TA, Laure A, Wildsoet C. Results of a one-year prospective clinical trial (CONTROL) of the use of bifocal soft contact lenses to control myopia progression. Ophthal Ophthal Opt 2006; 26(Suppl. 1):8-9
- Walline JJ, Greiner KL, McVey ME, et al. Multifocal contact lens myopia control. Optom Vis Sci 2013; 90(11):1207-1214
- Tarrant J, Severson H, Wildsoet CF. Accommodation in emmetropic and myopic young adults wearing bifocal soft contact lenses. Ophthalmic Physiol Opt 2008; 28(1):62-72
- Chia A, Chua WH, Wen L, et al. Atropine for the Treatment of Childhood Myopia: Changes after Stopping Atropine 0.01%, 0.1% and 0.5%. Am J Ophthalmol 2013
- Cullen AP. Ozone depletion and solar ultraviolet radiation: ocular effects, a United nations environment programme perspective. Eye Contact Lens 2011; 37(4):185-190
- Walsh JE, Bergmanson JP. Does the eye benefit from wearing ultraviolet-blocking contact lenses? Eye Contact Lens 2011; 37(4):267-272
- Allen PM, Evans BJW, Wilkins AJ. Vision and Reading Difficulties. London: Ten Alps; 2010
- Evans BJW. Orthoptic indications for contact lens wear. Cont Lens Anterior Eye 2006; 29:175-181
- Walline JJ, Jones LA, Rah MJ, et al. Contact Lenses in Pediatrics (CLIP) Study: chair time and ocular health. Optom Vis Sci 2007; 84(9):896-902
- Jones LA, Walline JJ, Gaume A, Rah MJ, Manny RE, Berntsen DA et al. Purchase of contact lenses and contact-lenses-related symptoms following the Contact Lenses in Pediatrics (CLIP) Study. Cont Lens Anterior Eye 2009
- Stapleton F, Carnt N. Contact lens-related microbial keratitis: how have epidemiology and genetics helped us with pathogenesis and prophylaxis. Eye (Lond) 2012; 26(2):185-193
- Johnson KL. Are we myopic about myopia control? Cont Lens Anterior Eye 2014
- Dumbleton K, Jones L. Editorial. Non-compliance: so what? Contact Lens Update 2011; 26th September 2011
- Soni PS, Horner DG, Jimenez L, et al. Will young children comply and follow instructions to successfully wear soft contact lenses? CLAO J 1995; 21(2):86-92
- Brennan N. 2014. Ref Type: Personal Communication