CET CONTINUING EDUCATION & TRAINING PEER REVIEWED 1 FREE CET POINT Approved for: Optometrists 44 4 OT CET content supports Optometry Giving Sight Dispensing Opticians Having trouble signing in to take an exam? View CET FAQ Go to www.optometry.co.uk 4 Optometric Management of Childhood Visual Problems do is not helpful to a practitioner confronted with a child patient. Instead the practitioner must consider many other aspects, and in this respect must consider each individual child on his/her own merits and risk factors. The second article of this series (see OT February 24, 2012) described the usual progress of refractive errors YOUNG CHILDREN’S VISION PART 5 C-18925 O/D in early childhood, the process of 18/05/12 CET emmetropisation, and that refractive Dr Margaret Woodhouse, BSc (Hons), PhD, MCOptom errors which do not emmetropise place Previous articles in this series have discussed normal visual development in a child at risk of strabismus and/or amblyopia. A reasonable procedure young children and ways of successfully testing a young child, including advice for a very young child would be to about adapting test techniques to optimise results obtained.This current article monitor the refractive error during the discusses the significance of the test results and what the practitioner should expected emmetropisation period and consider when deciding whether and what to prescribe for the child patient. consider prescribing for an error that is not reducing. An exception to this would be a child with disabilities such refractive error he or as Down’s syndrome or cerebral palsy, she would consider in which emmetropisation does not prescribing for a non- take place. A correction at an earlier strabismic age is warranted in such situations. child different ages. Such a At any age, a practitioner would survey might provide consider prescribing for an extreme useful error guidelines outside the expected for practitioners. The results are largely complete by 2-3 years, so at reproduced in Table this stage any refractive error is likely 1. What is somewhat to remain stable and the practitioner surprising is the very must determine the significance of the wide variation in the error for the child e.g. with regard to level of performance and comfort at school. error that warrants Refractive errors lying distribution. refractive optometrists Figure 1 Robert enjoying the experience of prism bars during assessment of binocular status (fusional reserves) (photo courtesy Mike O’Carroll) of hospital believe correction. Emmetropisation is Strabismus, amblyopia and anisometropia Considering the The prescription for prescribe for a child with strabismus in or amblyopia, irrespective of the age. hypermetropia usual practice would be to a 1 year old, the In a convergent strabismus with an minimum and maximum values show accommodative element, the full plus that at least one UK optometrist would prescription is usually given. Many In 2008 Jane Farbrother published the prescribe +2.00D for a 1 year old, practitioners would feel it appropriate results of her survey of prescribing while at least one other optometrist to refer a strabismic child to the practice would leave a child with 14.75D of hospital eye service (HES), but they hypermetropia would be advised to offer spectacle among optometrists.1 Each UK hospital optometrist was asked to indicate what level of uncorrected. Thus, discovering what other optometrists correction immediately, especially Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates Type of Refractive Error Age of Child 1 year 3 years 5 years Mean (D) -3.47 -1.87 -0.98 Min – Max (D) -0.50 -10.00 -0.25 -10.00 -0.25 -3.00 Mean (D) +5.02 +3.40 +2.54 Min – Max (D) 2.00 – 15.00 1.00 – 6.00 1.00 – 5.00 Mean (D) 2.63 1.60 1.13 Min – Max (D) 1.00 – 8.00 0.25 – 4.00 0.25 – 2.50 1.38 1.10 0.25 – 3.00 0.25 – 3.00 Isometropia Hypermetropia Astigmatism Anisometropia Hypermetropia Mean (D) 2.08 Table 1 Current prescribing practice by hospital optometrists for a non-strabismic child1 Min – Max (D) 0.25 – 8.00 in an accommodative case, so that persistent the than to put into practice; the third some benefit can be had in the interim two eyes of 1.00D or more should be article of this series (see OT March period whilst the child is waiting to considered abnormal. The practitioner 23 2012) discussed the difficulty of receive an appointment at the hospital. should therefore consider prescribing a young child wearing a trial frame Recent studies have shown that the difference, to prevent amblyopia. and how this can sometimes make it refractive correction alone (without However, the practitioner should take difficult to record a reliable corrected occlusion therapy) can successfully all the other factors into account in acuity, if the child is distracted by the treat amblyopia in a proportion of determining the absolute correction. discomfort and restricted field from cases, recommendation For example, if a child’s refractive the frame. Consider keeping to hand now is to provide spectacles for the error is R +1.50, L+4.00, then it may be a number of comfortable spectacle child to wear constantly for around 18 appropriate to prescribe the full plus, or frames that have been glazed with weeks before considering occlusion a reduced/modified correction such as different refractive powers. These can therapy. As with strabismus, even R+0.50, L+3.00 might be more suitable. be very useful in measuring visual if In difference acuity with a more comfortable frame between the eyes must be incorporated. (albeit with the nearest correction), a 2-4 and the practitioner refers the child to the HES, a spectacle correction every difference case the between full but also provides an indication as to should be given so that refractive treatment begins immediately. Visual acuity a child’s reaction to spectacle wear. A useful guideline would be to correct Uncorrected myopia will inevitably OT February 24, 2012) also described any refractive error that is reducing reduce distance visual acuity. However, the rarity of anisometropia, and a visual acuity. This is easier to say remember that young children have The second article of this series (see For the latest CET visit www.optometry.co.uk/cet 45 18/05/12 CET Myopia CET CONTINUING EDUCATION & TRAINING PEER REVIEWED 1 FREE CET POINT Approved for: Optometrists 18/05/12 CET 46 4 OT CET content supports Optometry Giving Sight Dispensing Opticians Having trouble signing in to take an exam? View CET FAQ Go to www.optometry.co.uk 4 only limited interest in distance instructions given for spectacle viewing. Most learning and wear. For example, a child at play activities take place at risk of convergent strabismus near (including watching TV!) will probably be advised full- and a child is not impaired time wear of a plus prescription. by low myopia when very A myopic child with a large young. Correction might wait exophoria at near will probably until the child begins to take benefit from spectacle wear for more interest at distance, and near work as well as distance. the take Children with heterophoria at parental advice on this. Once risk of decompensating should a child is at school, distance also undergo a full binocular activities such as board work vision become prism cover test for fusional practitioner might important, and a correction would be warranted. Figure 2 Daniel is choosing a frame investigation reserves), the The effect of uncorrected risk so of as the to (eg, evaluate heterophoria becoming a manifest strabismus. hypermetropia is more difficult to different plus lenses in place; again, predict and the practitioner should a range of glazed frames can be not assume normal distance visual useful to replace the trial frame. The Encouraging spectacle wear acuity. near minimum plus that renders a normal Many parents of young children express acuity should be paramount, along accommodative response might be a concern about how their child will with accommodation, useful starting prescription to consider. react to wearing spectacles, and some in determining when to prescribe. As described in the second article of have genuine struggles with their child. For prevalence studies, astigmatism this series (see OT February 24, 2012), Very few children will tolerate full- is usually considered significant when children with disabilities are at high risk time wear of spectacles from the start, 1.00DS or more. However, unless of accommodative deficits. These have so even if full-time wear is the ultimate prescribing a spherical component, been demonstrated in children with aim, it is unrealistic to expect it at the there is little argument for prescribing Down’s syndrome5 and cerebral palsy6 outset, and failure will inevitably result for astigmatism at this level and a slightly when distance refractive errors are fully in parents feeling inadequate. However, higher criterion of 1.50 or 2.00DS seems corrected, and in children with Down’s children do adapt and the practitioner more sensible. Again, practitioners syndrome the accommodative lag is should give parents appropriate advice. should other unaffected by single vision spectacles The first step is, of course, dispensing factors, such as the risk of amblyopia for hypermetropia.7 However, in both comfortable and stable frames (Figure in cases of unilateral astigmatism. conditions, from 2), as no child will wear frames that spectacles8-10 and rub or slip. The child should also be practitioners should be prepared to encouraged to select a frame that they prescribe such corrections for any child like, so that they are more likely to with a difficulty in accommodation. wear the spectacles. The next article A measurement recording also bear in of mind children bifocal/multifocal Accommodation Measurement of accommodation (see Article 3 of this series, OT March benefit in this series will address dispensing 23, 2012) is essential in deciding on whether hypermetropic prescriptions Binocular vision should be prescribed especially in The observed or predicted effect of children who cannot yet carry out near a spectacle prescription on a child’s reassure parents that their child will acuity measurements and/or describe binocular vision status should also accept spectacle wear, but will do symptoms. If a child demonstrates influence a practitioner’s decision on so in their own time. Some children an accommodative lag then he or what to prescribe. Family history will take weeks or even months to tolerate she should be offered a prescription. contribute to the assessment of a child’s spectacles. The amount of plus prescribed can risk of developing strabismus. Binocular spectacle lenses change how the world be decided by assessing the lag with vision status will also influence the looks to a child, and some children for children Secondly, in greater practitioners Remind detail. should parents Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates that resist new experiences. The lenses spectacles, take them off for him or her, when also magnify (plus) or minify (minus) (so that there is no compulsion) and Practitioners should take all visual and have distortions at the edges; stop the activity. Repeat the following functions into account and prescribe on all very good reasons for children day, gradually lengthening the time of the grounds of visual acuity, binocular to reject them. If this seems to be the activity or introducing a second vision, the problem, the practitioner could activity. Do not turn the process into a the risks posed of deficits, keeping consider a reduced correction to aid battle; if the child snatches the glasses in mind this adaptation process, as long as this off and throws them, do not react, but of visual is compatible with binocular status simply take a long time to pick them and is consistent with the initial up and put them away (thus removing About the Author reason for prescribing, for the first pair. attention). Any visible reaction on the Maggie Woodhouse is Senior Lecturer Parents should be advised to choose part of the parent will encourage the at the School of Optometry & Vision encourage child to throw the glasses again – after all, Sciences, Cardiff University, where she their child to wear their spectacles, it’s a great way to annoy mum and dad! specialises in paediatric optometry. favourite corresponding activity to to when they will Before too long, the child will She runs visual the the functions normal functions needed. and development in Special childhood. Assessment appreciate a hypermetropic child or watching will want television for a myope, and when what we the interests are visual development in the child has an adult’s undivided child’s pace, not the practitioner’s. children with Down’s syndrome and the to are spectacles near is have benefit eg, reading a book for attention. Place spectacles on the child the prescription wear them. aiming for, and Clinic, which caters for patients of all That’s ages with disabilities. Her particular at impact of visual defects on education. and start the activity, helping the child Conclusion to appreciate how much clearer or easier There are no guidelines for prescribing References the task is. Make the activity short (the for children; the practitioner must See www.optometry.co.uk/clinical. younger the child, the shorter the time). decide for him or herself, and of Click on the article title and then on If the child becomes frustrated with the course, in discussion with the parents, ‘references’ to download. Module questions Course code: C-18925 O/D PLEASE NOTE There is only one correct answer. All CET is now FREE. Enter online. Please complete online by midnight on June 15, 2012 – You will be unable to submit exams after this date. Answers to the module will be published on www.optometry.co.uk/cet/exam-archive. CET points for these exams will be uploaded to Vantage on June 25, 2012. Find out when CET points will be uploaded to Vantage at www.optometry.co.uk/cet/vantage-dates 1. When considering prescribing for a 3-year-old hypermetropic non-strabismic child, the average hospital optometrist would: a) Prescribe +3.00D b) Prescribe +4.00D c) Prescribe +14.75D d) Prescribe +2.00D 2. When managing a child with Down’s syndrome, the practitioner should: a) Be prepared to prescribe bifocal spectacles b) Fully correct hypermetropia in all cases c) Monitor until the end of the emmetropisation period d) Measure and record accommodative accuracy 3. If a child has refractive amblyopia, the recommended first step in management is: a) Referral to the Hospital Eye Service b) Prescribe spectacles for constant wear for 8 weeks c) Prescribe spectacles for constant wear for 4-5 months d) Begin immediate full-time occlusion therapy of the amblyopic eye 4. If a child requires a myopic correction, the following apply EXCEPT: a) Correction may not benefit a young child b) Correction will reduce convergence in esophoria c) Distance acuity will improve d) Objects will appear smaller 5. If a child has a hypermetropic refractive error, the following apply EXCEPT: a) The plus power required can be determined by dynamic retinoscopy b) It may be valuable to prescribe if there is a family history of strabismus c) Distance visual acuity will reduce; spectacles are for close work only d) All anisometropia over 0.75D should be corrected 6. If a child requires spectacles for full-time wear, you should advise the parents: a) To choose a cheap frame as it may get broken b) To encourage full-time wear from the first day c) That the child’s lazy eye may go blind if the spectacles are not worn d) That lenses present the child with an unfamiliar world For the latest CET visit www.optometry.co.uk/cet 47 18/05/12 CET a a