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Home , Cataract, Congenital cataract

Arch Dis Child: first published as 10.1136/adc.57.3.165 on 1 March 1982. Downloaded from

Archives of Disease in Childhood, 1982, 57, 165-167

Annotation Congenital , a cause of preventable child blindness is numerically the most serious complications-such as important cause of remediable blindness in children, or -is reduced, fewer operations are being far more common than, for example, retino- required, and can be treated blastoma or congenital glaucoma. surgically in the same way as other congenital The management of congenital cataract has been cataracts. profoundly altered during the last 15 years as the Advances in contact technology have made it result of a number of developments. Since the work possible to use extended wear contact lenses for the of Wiesel and Hubel,1 and that of many others, correction of in infants. Contact lenses are clinical ophthalmologists have been aware of the readily fitted without anaesthetic and the tolerance relevance of in the management of visual rate is high despite the high . It is disorders in childhood. Amblyopia implies a loss of possible in most cases to overcorrect the aphakic vision that occurs as a result of visual deprivation to make the lens eye combination myopic so that the during a sensitive period of development ofthe visual infant can clearly see objects at some point within 1 system. The neurophysiological and anatomical metre which is his main sphere of visual interest in changes that are the substrate of the visual loss occur the first months of life when the brain is particularly throughout the visual pathway possibly even from sensitive to the degraded visual input. Satisfactory the retinal receptors to the cortical areas where correction of aphakia cannot be achieved in infants perceptual processing occurs. From human analogies by means of spectacles which, because of the very of the experimental animal it has been concluded2 3 high power lenses required, are impracticably heavy that in infancy there may be a period of grace of up and optically unsatisfactory. The use of intraocular to age 2 months when the effects ofvisual deprivation lens implants in infants is not recommended at the are of less consequence in that they are less profound present time because of uncertainty about long-term http://adc.bmj.com/ and reversible. After this period there are 6 to 18 complications. months ofincreased sensitivity, the human equivalent of the experimental animal's critical period, followed Presentation by a gradually declining sensitivity for several years Unilateral congenital cataracts present because of so that by age 9 or 10 years a child's is the appearance of a white , small eye, or not deranged by degraded visual imput. Amblyopia unilateral squint noticed by parents or relatives. The can be caused not only by opacity in the optical smallness of the eye is usually marginal and it may media of the eye-such as cataract-but also by a be thought that the other eye is large. The white on October 4, 2021 by guest. Protected copyright. blurred retinal image such as occurs in uncorrected pupil is more often described as milky, hazy, or as aphakia (the absence of the lens from its normal site, 'just not looking right', it may be seen only in certain for any reason, with the loss of its refractive role). lighting conditions and should therefore be a The impact of greater understanding of the symptom to be believed even if not seen. mechanisms of amblyopia on the management of Bilateral congenital cataract often occurs if other cataract has been twofold: now realise that members of a family are affected, and it is these most children with congenital cataract who require patients who are best poised for ideal management. surgery in infancy should have that surgery Parents notice early that their baby does not seem to completed by age 2 months; and early accurate look at them and they may also notice white . correction of aphakia is essential if a sharp retinal By age 3 months a baby with severe bilateral cataracts image is to be produced during the sensitive period. will start to develop nystagmoid movements on There have been important changes to the surgery attempted fixation and this, or an associated squint, of congenital cataracts in recent years4 5 and these is generally the mode of presentation in what are now have substantially improved the short- and long-term regarded as late cases, since they seem to indicate that prognosis for the eye. The of very young infants the visual system is already reacting to visual can be operated on with safety, the likelihood of deprivation, 165 Arch Dis Child: first published as 10.1136/adc.57.3.165 on 1 March 1982. Downloaded from

166 Taylor and Rice Diagnosis Management

Diagnosis at the clinical level is generally made It may be difficult to decide whether a cataract initially by the paediatrician who listens to the requires treatment. The optical disadvantages of mother's worries about the baby's vision, the aphakia, combined with the risks and possible appearance of the pupils, or the presence of failure of treatment, make it inadvisable to operate or squint. Careful inspection of the eyes and start optical treatment unless it is certain may show the small eye or the white pupil, but the that the child will be visually handicapped unless absence of a white pupil does not exclude a cataract he is treated. Most cases fall clearly into the since the opacity may be posterior in the lens. One 'obviously blind' or 'obviously sighted' category but useful technique is to look at the eye with an the management of border-line cases must be ophthalmoscope as though one is going to look at the decided by a variety of techniques. If some form of fundus but keeping about a foot away; the absence of infant vision testing device-such as visually-evoked a is a clue to an opacity in the refractive cortical responses or forced preferential looking- error. Closer inspection with the ophthalmoscope is are available the choice may be easier. However, these possible if the lens system of the ophthalmoscope is techniques are not widely available nor are they set at +20 dioptres. If a cataract is suspected, universally accepted as an accurate index of vision in referral to an ophthalmologist should be arranged as infancy. The ophthalmologist may make some an urgency, especially if the baby is less than i-year judgement by the clarity with which he sees the old. fundus with an ophthalmoscope, but this technique A search for the aetiology of the cataract is must be inaccurate because of the very poor correla- important but should not delay the management of tion between the degree and site of the opacity in the the cataract itself. refractive media and the vision of the child in cases About one-third of congenital cataracts are where this can be measured. Therefore the doctors genetically determined, and there are also certain managing the child must rely on behavioural morphological types that are found more frequently observations in borderline cases. If the infant fixes in genetically-determined cataracts. However, some objects steadily without nystagmus or squinting, and genetically-determined systemic diseases are also responds to subtle clues-such as a silent smile or associated with cataract-for instance galactosaemia, movements of small objects-it is unlikely that his Lowe's syndrome, and lactose intolerance as well vision is sufficiently poor to warrant early treatment. as numerous syndromes of unknown causes of If there is any doubt there is very little to lose by

which the most common are the Hallermann- reassessing the child after an interval of one or two http://adc.bmj.com/ Streiff, Rubinstein-Taybi, and Conradi-Hunermann weeks. In borderline cases, repeated examinations syndromes. may help to make this critical decision. Cataracts are often found in babies with Down's syndrome, and also with trisomy 13 and 18, and in Bilateral congenital cataracts Turner's syndrome. In the congenital rubella syndrome the cataracts are generally present at Bilateral congenital cataract is the most common birth and about one-third are uniocular.f They are cause of potentially treatable blindness in infancy. It usually present as a part of the whole syndrome but now seems likely that, although the results are not on October 4, 2021 by guest. Protected copyright. occasionally the cataract is the only abnormality universally successful, early surgery leads to better detected initially. The early detection of the cataract visual results provided that optical correction is and management of it are especially important in started early.7 If diagnosed in the neonatal period it view of the high incidence of deafness as the child is reasonable to wait for 2 or 3 weeks before admitting grows older. Cataracts are less common in other the child to hospital for in order to make prenatal infections. Metabolic causes include galacto- the surgery somewhat easier. Unfortunately however, kinase and deficiency, Lowe's syndrome, delays in diagnosis and referral result in most babies and hypocalcaemia. with bilateral severe congenital cataracts being seen Investigations should be carried out after by the ophthalmologist for the first time between consultation between ophthalmologist and paedia- 2 and 4 months of age. By age 4 months one must trician, each of whom will be able to exclude cer- expect the effects of visual deprivation to be showing tain causes on clinical grounds thus saving time their mark and the counsel of perfection is that all and money on unnecessary tests. This par- patients should be referred early so that, if necessary, ticularly applies to galactose metabolism tests as surgery and optical correction can be completed by these are expensive to carry out in detail but inexpen- age 2 months. After surgery the baby is fitted with sive to screen for. continuous wear high gas-transfer contact lenses Arch Dis Child: first published as 10.1136/adc.57.3.165 on 1 March 1982. Downloaded from

Congenital cataract, a cause ofpreventable child blindness 167 without anaesthetic.8 There is a substantial risk of incidence of late visual deterioration due to macular corneal damage from these and frequent follow-up degeneration." visits are necessary; this, together with a high rate of lens loss and rejection, must be explained to the Conclusion parents at the beginning of the treatment. The contact lenses are not strictly necessary once the Studies in amblyopia have led to the wider recogni- child is old enough to wear spectacles and we try to tion of the importance of early treatment of ensure that the patient is wearing spectacles all the congenital cataracts. The management is difficult, time by age 3 and that he is wearing bifocals by school especially for the parents and the child, but the age. enhanced visual result in the majority of cases The cost of contact lens treatment, both to the justifies the difficulties and the risks. There is a clear parents and to the NHS is admittedly high, perhaps responsibility on paediatricians and others concerned between £200 and £1200 a year, depending on the in the care of children to be aware of the importance numbers of lenses used and the distance from the of congenital cataracts and the need for prompt contact lens department, but if one can show an referral to the ophthalmologist. improvement in the child's visual performance sufficient to shift it from one educational category References to another, even the fiscal argument is clearly Wiesel T N, Hubel D H. Effects of visual deprivation on one-sided. morphology and physiology of cells in the cat's lateral geniculate body. J Neurophysiol 1963; 26: 978-93. Unilateral cataract 2 Vaegan, Taylor D. Critical period for deprivation amblyopia in children. Trans Ophthalmol Soc UK 1979; 99: 432-9. Until recently it was universally agreed that the 3 Awaya S. Stimulus vision deprivation amblyopia in visual prognosis for eyes with unilateral cataract was humans. In: Reinecke R D, ed. . Proceedings so poor that surgery was indicated only for cosmetic of the third meeting of the International Strabismological reasons or to prevent glaucoma resulting from a Association. New York: Grune & Stratton, 1978: 31. 4 Rice N S C. Lens aspiration-a decade in retrospect. 'hypermature' lens. Recently Beller et al.9 described a Trans Ophthalmol Soc UK 1977; 97: 48-51. series of children who were operated and optically 5 Taylor D. Choice of technique in surgery for congenital corrected within days of birth. This was followed by cataract. Trans Ophthalmol Soc UK 1981; 101: 1 14-7. vigorous occlusion of the normal eye and careful 6 Dudgeon J A, Peckham C S, Marshall W C, Smithells R W, Sheppard S. National congenital rubella monitoring of the vision of both eyes by psycho- surveillance programme. Health Trends 1973; 5: 75-9. physical or electrophysiological means. By the time 7 Taylor D, Vaegan, Morris J A, Rogers J E, Warland J. http://adc.bmj.com/ of publication 9 of their patients who had received Amblyopia in bilateral infantile and juvenile cataract. ideal treatment had Snellen acuities of about 6/9. Trans Ophthalmol Soc UK 1979; 99: 170-5. This series has yet to be reproduced at another centre 8 Morris J, Taylor D, Rogers J E, Vaegan, Warland J. Contact lens treatment of aphakic infants and children. but quite apart from its significance in the under- J Br Contact Lens Assoc 1979; 2: 22-30. standing of human amblyopia, it may be of some 9 Beller R, Hoyt C S, Marg E, Odom J V. Good visual interest in the management of patients with unilateral function after neonatal surgery for congenital monocular cataract. This is especially important in view of the cataracts. Am J Ophthalmol 1981; 91: 559-65. increased vulnerability to of a single normal 10 Tommila V, Tarkkanen A. Incidence of loss of vision in on October 4, 2021 by guest. Protected copyright. the healthy eye in amblyopia. Br J Ophthalmol 1981; 65: eye when its fellow is amblyopic.10 The social 575-7. relevance of extended, and possibly risky, treatment Frank K E, Purnell E W. Subretinal neovascularization for a non-blinding condition is more a matter for following rubella . Am J Ophthalmol 1978; 86: debate than that of bilateral cataract. 462-6. DAVID TAYLOR Rubella Hospitalfor Sick Children, Great Ormond Street, Rubella cataract still poses several problems. The London WCJN3JH notion that rubella was best delayed for some months or even years because of the risk of NOEL S C RICE has now been outdated by improved Moorfields Eye Hospital, surgical technique, and bilateral rubella cataracts City Road, require early surgery like any others. In rubella there London EC] W 2PD is probably a stronger than normal indication to treat unilateral cataracts since there is a substantial Reprint requests to D Taylor.