PREMATURE BABIES. Early care for infants with a visual deficit.

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1 PREMATURE BABIES. Early care for infants with a visual deficit. Mercè Leonhardt Early care coordinator Joan Amades Resource Centre, ONCE, Barcelona. Spain melg@once.es EUR 026 Early care for children with a visual deficit has been in place in Spain since This paper addresses the specific characteristics of blind infants from the very earliest stages of life, as well as the effects of low vision and multi disability on babies. One of the items of primary importance in our work is the support provided parents in their relationship with their newborn. Being able to assist parents and their child as soon as the deficit is detected affords us the opportunity to help them through the first few difficult moments of sorrow and confusion experienced by all parents in such situations. And initiating visual stimulation in a period of enormous sensitivity greatly enhances the infant s potential for change. Early detection has been and continues to be a major concern in Spain, and the inspiration for our work from the outset. Ongoing exchange with neonatologists, ophthalmologists and neurologists has always been a priority in early detection. The neonatology scenario has changed of late in Spain. At this time 10% of all births are premature. Such a high figure is attributed to: Increases in multiple births Higher percentage of assisted reproduction Later age at maternity Pregnancies in women with health problems Higher pregnancy rates among recent immigrants and disadvantaged social classes. Parents, moreover, are not particularly young (over 30). Pregnancies are generally wished for and planned. Couples have one or two children at most 1

2 These children s arrival is carefully prepared. Their name and characteristics are known in advance. And they are expected to be healthy or to have a prenatal diagnosis. Consequently, parents are not generally prepared to face the problems that prematurity can create and the concomitant difficulties that may arise. The stimulus provided by environmental light is needed for vision to develop normally. The administration of early treatment to premature babies in ICUs whose physical condition allows calls for an early organic and functional diagnosis of their visual condition. We ran a pilot study in this regard to establish an approximate understanding of the visual development in infants born before term. That understanding is essential to the clinical efforts geared to the early protection of neurosensory development. And while a knowledge of visual development is necessary in the care of all infants, it is of crucial importance in the clinical care of preterm babies and newborns at risk in neonatal intensive care units. In addition, preterm newborns have a higher rate of visual, cognitive and motor alterations than full term infants. Due to the bodily immaturity of premature babies, their visual function is sometimes observed to be retarded. Alterations in the visual development of such infants may also arise as a result of prematurity related clinical complications: premature retinopathy, periventricular leukomalacia, intraventricular haemorrhaging, hydrocephaly Hence the need for an accurate understanding of their visual process when there are no alterations, their actual visual capacities, the existence or otherwise of visual or perceptive difficulties, the possible signs of such difficulties, and how to recognize the mechanisms that may contribute to improving their visual performance. Stimuli such as too much light or other stress factors including sleep deprivation or extended sedation may indirectly impair early visual development. Excessive light has been shown to have deleterious effects on the development of central vision in preterm newborns. Our clinical practice has shown that despite the foregoing limitations, premature infants develop a number of visual functions, although this is scarcely documented in medical literature. In fact, while comparative surveys have identified no differences in the visual acuity of preterm and full term infants, and premature babies are often observed to be very attentive to and explore visual stimuli, following them for more or less the same length of time as other babies, visual fatigue appears sooner in preterm newborns. 2

3 KNOWLEDGE OF VISUAL DEVELOPMENT. STATE OF THE ART The importance of luminous stimuli in visual development has been reported in studies on animals. This hypothesis is supported by the pioneering experiments conducted by T.N. Wiessel and D. Hubel, in which monocular deprivation of light in kittens gave rise to abnormal ocular predominance. More recent research with babies has shown, however, that significant reduction in the intensity of light has no adverse consequences for the development of central vision. One example is a randomized Canadian study that evaluated the effect of ocular occlusion in 29 week or less preterm newborns by conducting potential visual evocations when they reached term age and two months later. They found no significant differences between the group of babies subjected to occlusion and those who were not. Shatz et al. studied the visual cortex, including the role of endogenous and exogenous stimulation. The neurosensory development of the visual system is presently believed to comprise three essential processes: 1. Stimulation independent, genetically determined processes. This phase includes division, differentiation, migration and initial cellular alignment, as well as initial axon growth. The position and distribution of cones, rods and retinal bipolar cells are genetically determined in this process. 2. Spontaneous endogenous stimulation. Without such stimulation, the alignment of the external geniculate body cells would be a mere gross approximation of the topography of the retinal cells. 3. Exogenous stimulation processes consisting in visual and other sensory stimuli. In the near full term foetus, the visual system is prepared to receive light and visual experience. The reflex that controls the pupillary reaction to light is believed to develop by around the thirtieth week of gestation. The full term visual system has visual receptor cells (cones and rods) and functional connections to the visual cortex. Four types of channels are proposed for the transmission of visual stimuli from the retina to the visual cortex for form, movement, binocular vision and colour, although there is no clear cut functional separation between them. At birth, full term newborns can receive visual stimuli for lines, forms, movement and luminous intensity. 3

4 Visual experience is essential to the ongoing development of the visual system. Drugs and powerful exogenous stimuli may interfere with transmission and occasion alterations in this phase of neurosensory development. In view of our results, we have begun to develop a series of techniques and tools that can be used to aid and improve care for preterm infants in the ICUs in hospitals in Barcelona and the surrounding area. To this end, one of the aims sought has been better control of the luminous stimulus received by premature infants in incubators. This has been achieved by placing a hood with green carvings over incubators from the infants 22nd to 30th week. During this period, the hood is gradually opened so the child progressively receives more light as it grows. When the baby is held by its parents against their bodies during kangaroo care sessions, the light in the ICU is dimmed. At the same time, babies cardiac rate and oxygen saturation is monitored. When the hood is on the incubator, the baby s saturation is appropriate and the child is relaxed. When the hood is removed, saturation declines and the baby shows signs of stress. The fact that this should concur with the objective results observed by neonatologists for infants subjected to this treatment comes, then, as no surprise. To date, none of the infants has haemorrhaged during the period when the incubator is covered. The procedure benefits not only the infant s visual system, but especially its brain. We have also devised an observation protocol to evaluate both the visible appearance of babies eyes and their visual function. External ocular alterations may be readily recognized by health care professionals in hospitals with no paediatric ophthalmologist, and it is such alterations that the items listed help to evaluate. The protocol also enables professionals to identify visual function as denoted in a newborn s gaze. Moreover, there is a space at the end of the protocol to record ocular alterations or anomalies in visual function, and to note whether visual stimulation has been initiated. The different guidelines to be taken into account are likewise listed, as well as the referrals to be made: to the ophthalmologist for monitoring and diagnosis, to our centre in the event of severe visual deficiency or to the paediatrician for monitoring in indecisive cases. (The protocol is attached as an annex to our presentation.) In keeping with the ONCE s policy of pioneering research in new areas, the annex also contains a set of patterns or visual models for premature infants to observe and monitor the visual process developed by such babies in very early stages, as discussed above. This descriptive survey is being conducted with fifty 33 week or less preterm infants. We previously worked with a control group of 25 full term babies with whom the set of patterns was applied just hours after they were born. The data were compiled and processed by the University of Barcelona. 4

5 The set of patterns consists of 14 optotypes and three additional visual stimuli: a human face, a red box that can emit sounds and a 5 cm diameter red ball. The optotypes will be shown in our presentation, along with the protocol for maternity ward observation. The outcome of our studies has led us to undertake very early visual stimulation, in which we have found infants visual response to be highly surprising. Moreover, this contact with premature babies provides an opportunity to offer their families appropriate assistance and guidance in coping with their child s visual deficit. Early detection not only facilitates early care for newborns with a severe visual deficit via early stimulus of the child s possible visual functions or capacities in blind infants, but affords the possibility to provide emotional support for parents in a state of personal confusion and suffering that generates ambivalent feelings towards their baby. An understanding of all their child s processes and capacities, despite the shortcomings that visual deficit entails, enables parents to face the future a real and possible future with intense love, desire and hope from the very beginning of their baby s life. 5

6 PROTOCOL FOR OBSERVING VISUAL BEHAVIOUR IN NEWBORNS Child s name Date of birth Age Diagnosis Hospital 6

7 Mercè Leonhardt / CDIAP CRE Joan Amades Av. d Esplugues, Barcelona, Spain) tel PHYSICAL APPEARANCE path norm unce o al r tain logic al External appearance of eyes (microphthalmia, anophthalmia, leukocoria, ptosis, blepharophimosis,...). Anomalies in pupils (deformed: tear shaped or total or partial absence of iris). 7

8 Pupillary light reflex? (dilation, constriction when light is shone into the eye). Anomalies in cornea size or transparency? (megalocornea or reduced size, keratoconus, opacity, increase in diameter (glaucoma)). Opacity of the crystalline lens (cataracts). Altered ocular movement (erratic, nystagmus, oculomotor paralysis). Vestibulo ocular reflex (VOR). Constant strabismus? (ocular deviation due to premature retinopathy, or eyes oriented upwards or downwards, tumour). 8

9 Physical appearance Protocol for observing visual behaviour in newborns (2) VISUAL FUNCTION path norm unce o al r tain logic al Does the infant seek or always conspicuously avoid bright light? Does the child make eye contact? Does it sustain eye contact? 9

10 Does it observe the mother s or others face attentively? Does it briefly fix on faces crossing its visual field? Does it visually recognize the mother? Does it notice a luminous or attractive silent object at a short distance from its eyes? Can it follow another face with horizontal and/or vertical movements,. with its face. with its eyes 10

11 Visual function Protocol for observing visual behaviour in newborns (3) path norm unce o al r tain logic al Can it follow a silent object close to its eyes horizontally, vertically, in circles? It is visually alert? If not, is it alert to sound? Does it smile socially? 11

12 Preferred visual technique: the child is presented with two stimuli. It directs its gaze towards the most attractive of the two or the one it perceives (for instance: thicker and thinner lines, drawing of a face, a circle or a square,...). Visual function Protocol for observing visual behaviour in newborns (10) REFERRAL 12

13 Examination 1 Examination 2 Examination No. Examination Examination Examination Referral Date Ophthalmologist Paediatrician CDIAP CRE Joan Amades Date Remarks 13

14 Date Recommendations Referral Protocol for observing visual behaviour in newborns. 14