C37970: Correction of Early Onset Myopia

Closing Date: 17/10/2014

Communication Paediatric dispensing Refractive management

The idea that vision correction will make a child’s eyes worse is arising more frequently in consultations

The idea that vision correction will make a child’s eyes worse is arising more frequently in consultations

My child’s myopic correction will weaken their eyes. Wearing spectacles for myopia will encourage the prescription to increase. I just don’t want my child’s face to have glasses on it… Sometimes, in practice, parents of newly diagnosed myopic children are reluctant for them to wear spectacles – their resistance often being grounded in a variety of reasons that might be instinctive for eye care practitioners to dismiss as misplaced. Some, such as cosmetic concerns, we are best equipped to deal with as sympathetic human beings; others, such as concerns over increasing prescriptions, cannot always be assuaged by a comforting word and instead need to be dealt with more scientifically.

The idea that ‘wearing glasses will make my child’s eyes worse’ is arising more frequently during consultations. In my practice, as an example, a young girl was found to require around a -2.00DS correction in each eye and was very keen on the idea of contact lenses to eventually go with her first pair of spectacles. While on the face of it, we would have been happy to at least begin a trial fitting, her father was very much against this idea. He was concerned that, while spectacles could be removed when not particularly needed, the more constant correction by contact lenses would cause her prescription to increase and her uncorrected vision to become progressively poorer. He had done some reading up on early onset myopia (EOM) and believed that he would be serving his daughter’s best interests by encouraging her to remain uncorrected for as much time in the day as she could manage. This is exactly the kind of parent who needs to hear a more evidence-based argument if he is to be convinced that his daughter should wear her not-insubstantial correction more often.

Whatever the reason for a parent’s reluctance for their child to wear their spectacles, whether they are specifically worried about EOM or some other concern, the knee-jerk response from the practitioner is often ‘well of course it’s better to wear the correction’. However, by reviewing and being even a little more aware of current literature that offers guidance to what the best course of action would be, the practitioner can use any conclusions to offer more evidence-backed advice.

Early onset myopia

EOM describes a continued increase in myopia during early years, typically from around five years old, with the prescription sometimes fluctuating until as late as around the age of 21.

For myopia in general, the misplacement of the retinal image (forward of the retina) can be caused by one of three things – the effective refractive index of the eye being too high, the optical system of the eye being too powerful due to curvature of the cornea or crystalline lens, or the axial length of the eye being too long. EOM is generally considered as a variant of the third type, a kind of axial myopia, because it is thought to be centred around the eye gradually becoming longer than would be ‘matched’ with the eye’s optical system as the patient grows and develops.

Due to an apparent stabilisation of EOM at around -3.00D,1 early research into its cause investigated a theorised link between prolonged accommodation during near work (a -3.00D uncorrected myope normally will not accommodate any more for near work) and the magnitude of myopia. Dispensing solutions aimed at working to this idea include bifocals and progressive-power lenses to reduce the accommodation required for near. These multifocal options have themselves occasionally been rejected by parents because of cost or cosmetic grounds.

Small communities have appeared to show variation in myopia to correlate positively with an individual’s amount of near work.2 However, larger, more genetically diverse communities that all share a higher level of near work may show a general increased risk of EOM,3 but not at the consistent level to be expected if near work were the only factor. As well as these potential links to heredity and near work, other influences in EOM have ranged widely from time spent outdoors exposed to daylight to the elasticity of the choroid. (A full review of the genetic and environmental influences on myopia will appear in Optician in the coming months.)

This is only a brief summary of theories as to the cause of EOM. Research into a definitive list is ongoing and this in itself is perhaps a useful point to make to patients in practice: there is no convincing evidence to suggest whether wearing a correction more or less has any effect on the progression of a child’s myopia.

Where parents are concerned about their children wearing some form of vision correction, whether concerned about EOM or otherwise, it is worthwhile examining evidence for how (and how much) that correction will affect their child’s quality of life.

Quality of life

A general description of how poor unaided vision affects quality of life may help parents accept advice regarding correction. Sometimes parents just don’t appreciate what their child is experiencing without their spectacles.

The scientific assessment of quality of life is problematical as the child may simply be unable to participate in the required studies accurately. It would also be difficult to convince an ethics committee to allow a child to be deprived of current best practice for them to act as a control subject. A wider, perhaps compromised, approach is more desirable.

Instead of only referring to literature on vision-related quality of life in children, we can also examine comparable adult situations (where a patient’s vision has altered in some way). The lifestyle of children with vision-related problems could be used to suggest if there are any patterns in activities or habits among different groups of children and to judge (although with a degree of personal bias) whether these activities suggest a better or worse quality of life.

A study by Lazon de la Jara et al4 found, through analysis of quality of life questionnaires post-Lasik surgery, a statistically significant correlation between improved unaided vision and a perceived improved quality of life. Lasik surgery is designed to improve unaided vision, so can perhaps be compared to dispensing spectacles to improve visual acuity. It should be noted that there is a potential bias arising from the fact that all members of this study had chosen to have refractive surgery. They can be assumed to have already been dissatisfied with their existing visual acuity for whatever reason.

This improvement could be ascribed to either improved vision, or simply no longer having to wear the spectacles associated with myopia. It is only suggested (rather than certain) that the improved quality of life found would be paralleled through the dispensing of spectacles to correct myopia.

Another, perhaps closer, analogue could be found by looking at studies of post-cataract surgery patients. The most significant vision-related difficulties arising from lens opacities cannot be corrected with spectacles. Any differences in quality of life before and after having them removed is less likely to be due to removing the inconvenience of physically wearing spectacles (although phako surgery does generally aim to leave patients emmetropic for distance).

Various trials concerned with quality of life after cataract removal have been conducted, eg He et al5 and Zhao et al.6 For our purposes, strictly speaking, all have slight flaws. Some studies encompass patients whose uncorrected vision had previously been much poorer than EOM would be likely to cause on its own and some have results that are not statistically significant. Additionally, the patients involved in all of these studies are more likely to be far away from the younger age range we are concerned with.

However, taking all of these potential ‘flawed’ studies into account, a meta-analysis of this range of results paints a general picture that perhaps should not be disregarded: generally, it appears it is likely that people find life better with clear vision following an intervention such as phako surgery.

While expert opinion technically falls fairly low on the hierarchy of evidence, it is perhaps also worthy of mention that the World Health Organization has made specific mention of people’s difficulty in working due to uncorrected refractive error, the negative impact on quality of life this causes and its potential correction with spectacles.7

Some specific aspects of children’s quality of life have been studied. Horwood et al8 conducted a study of children who suffer with some form of visual defect (including wearing spectacles) and those who do not, reporting on perceived levels of victimisation among each group. It was found that 61.5 per cent of children who did not wear spectacles never experienced any victimisation, compared with 53.9 per cent of children who did wear spectacles.

This would suggest that wearing spectacles potentially makes a child slightly more likely to be bullied by their peers. The authors of this study do suggest, however, that this could be addressed by simple education programmes for pupils and increased awareness in school staff.

Myopia’s place in general lifestyle

As part of the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) project, a study found that children with myopia spend fewer hours on average playing outdoor sports, as well as spending more hours playing video games,9 than their non-myopic peers. It may be subjective to say whether either of these factors are synonymous with a better or worse quality of life, but several studies have shown a link between regular exercise and a reduction in the occurrence of heart disease, as well as other health complaints.

The study concludes that it is unclear whether children enjoy and pursue activities primarily involving near vision after first developing myopia (because they can more comfortably see near tasks), whether their myopia is a result of spending more time viewing near objects while corrected for distance, or whether children who are pre-disposed to myopia are also pre-disposed towards enjoying indoor activities for some other reason. This question, as well as possible more direct links between myopia and general health, is being explored by further research.

Wearing spectacles offers the clear vision to lead a healthy lifestyle – both in the classroom and outdoors

Wearing spectacles offers the clear vision to lead a healthy lifestyle – both in the classroom and outdoors

Studies begun in 2013 have started exploring a potentially more fundamental relationship between light exposure and myopia. They are examining the theory that it isn’t necessarily physical activity outdoors that helps to stave off EOM, but perhaps just the amount of time a child spends outside.10

On a related note, sometimes parents are concerned about their children’s ability to take part in an active lifestyle while wearing spectacles. Depending on the parent’s specific concerns, eye care practitioners have several areas of discussion. These can be explored during the dispense, but ideally introduced by the optometrist during the eye examination.

There is an ever-increasing range of prescription-ready sports appliances that many eye care practitioners are familiar with, from wraparound frames to protective spectacles and swimming goggles. Additionally, a discussion about the ready availability of sports specific corrections may lead nicely into talking with parents and children about how common refractive error is among people who enjoy active lifestyles.

There is also the option of fitting children with contact lenses. This is, of course, down to the contact lens fitter’s discretion, but in the author’s practice some of the most keen and, importantly, compliant patients are young people motivated by enjoying the visual benefits of a moderate myopic correction for the first time.

Conclusion

The literature strongly suggests that perceived quality of life is improved with better visual acuity. Research into the lifestyle habits of myopic children does not make it clear whether these habits would be altered by the children being dispensed spectacles, or whether they are related to being myopic for some other reason. Further research may decide whether there is a link between myopic correction, visual acuity, and health in general. There is some evidence to suggest that wearing spectacles increases the incidence of bullying in children, but also that this can be negated by appropriate support programmes in schools.

It is reasonable to draw the conclusion that overall it is preferable to correct myopia in children when faced with the alternative of wearing no correction at all, or wearing it for limited periods. There is more (and statistically more significant) evidence that quality of life improves with visual acuity than there is to suggest that quality of life is reduced through either increased levels of myopia (due to the correction accelerating EOM) or the practice of wearing spectacles itself.

It is undoubtedly sound common sense to instruct a patient (or their parent), where necessary, that wearing their spectacles is a good idea. However, as some parents gradually become more aware of the idea that ‘wearing glasses might make their child’s eyes worse’, or resist their child wearing correction for some other reason, common sense may not be sufficient when talking to a concerned or misinformed parent. In these cases, it is useful to be able to draw on actual evidence to support this long-assumed advice.

I choose to consider it fortunate that the most recent research into finding a direct cause for myopia in children points towards general advice that is simple and satisfying for a practitioner to give to a child: enjoy the clear vision that a pair of spectacles can provide to lead a varied, healthy lifestyle – both in the classroom and outdoors.

Model answers

The correct answer is in bold text

1 Evidence on the subject tends to suggest that a person's quality of life has the strongest correlation with which of the following?

A Their standard of vision is improved

B Their peers are aware of a need for correction

C They wear spectacles for sport instead of contact lenses

D The nature of a child's refractive error is identified

2 Which has not been linked to myopia progression in young people?

A The wearing of full time correction

B A family history of myopia

C Large amounts of near work

D Low levels of outdoor activity

3 What might an optician reasonably consider to improve a myopic child's quality of life?

A Discussing alternative optical corrections for sport

B Admonishment for not wearing their spectacles all the time

C Dispensing them zero-powered 'practice' glasses to try, then a prescription pair later

D Dispensing spectacles to their siblings to encourage their use

4 Which of these is FALSE?

A Full time correction leads to progressive increased strength correction being required

B Children who spend less time outdoors tend to be myopic

C Children who wear spectacles are more likely to be bullied in school

D Myopia is partly genetic

5 Which of the following statements about studies of pseudophakes regarding quality of life is true?

A There is conclusive evidence of improved quality of life post-surgery

B There is no evidence of improved quality of life post-surgery

C There are flaws in most

D The sample under study corresponds well with those experiencing early onset myopia

6 Which of the following statements about quality of life for LASIK patients is true?

A There is no evidence of improved quality of life post-surgery

B There are flaws in most

C There is a statistically significant correlation reported between post-refractive surgical vision and quality of life

D Any study of post-LASIK surgery subjective opinion will be free of patient bias

References

1 Young FA. The development and control of myopia in human and subhuman primates. Contacto, 1975; (19): 16.

2 Young FA, Leary GA, Baldwin WR, West DC, Box RA, Harris E et al. The transmission of refractive errors within Eskimo families. American Journal of Optometry and Archives of Optometry, 1969; (46): 676.

3 Oakley KA, Young FA. Bifocal control of myopia. American Journal of Optometry and Physiological Optics, 1975; (52): 758.

4 Lazon de la Jara P, Erickson D, Erickson P, Stapleton F. Visual and non-visual factors associated with patient satisfaction and quality of life in Lasik. Eye, 2011; 25(9): 1194-1201.  (accessed 4 February 2014).

5 He M, Xu J, Li S, Wu K, Munoz SR, Ellweint LB. Visual acuity and quality of life in patients with cataract in Doumen County, China. Ophthalmology, 1999; 106(8): 1609.  (accessed 4 February 2014).

6 Zhao J, Sui R, Jia L, Fletcher AE, Ellweint LB. Visual acuity and quality of life outcomes in patients with cataract in Shunyi County, China. American Journal of Ophthalmology, 1998; 126(4): 515-523.  (accessed 4 February 2014).

7 World Health Organization. WHO | Sight test and glasses could dramatically improve the lives of 150 million people with poor vision. (accessed 4 February 2014).

8 Horwood J, Waylen A, Herrick D, Williams C, Wolke D. Common visual defects and peer victimization in children. Investigative Ophthalmology & Visual Science, 2005; 46(4): 1177-1181.

9 Jones-Jordan LA, Mitchell GL, Cotter SA, Kleinstein RN, Manny RE, Mutti DO, Twelker JD, Sims JR, Zadnik K. Visual activity before and after the onset of juvenile myopia. Investigative Ophthalmology & Visual Science, 2011; 52(3): 1841-1850. .

10 French AN, Ashby RS, Morgan IG, Rose KA. Time outdoors and the prevention of myopia. Experimental Eye Research, 2013; 114(September 2013): 58-68. (accessed 12 February 2014).

Ben Brewer is a dispensing optician based in Devon