In Neural Science and Vision – Part 5, we mentioned Lea Hyvärinen, MD, PhD and her book What and How Does This Child See, 2nd edition co-authored with Namita Jacob, published at the end of 2019. Our blog introduced Dr. Hyvärinen as a developmental/behavioral ophthalmologist who spoke at the COVD meeting in 2012. Since then, as is apparent in her book, Dr. Hyvärinen has evolved in the direction of neuro-rehabilitative ophthalmology to parallel neuro-rehabilitative optometry. Inventor of the eponymous Lea tests, Dr. Hyvärinen has few if any ophthalmologic peers in the U.S., her closest analog perhaps being Dr. Gordon Dutton in the U.K. In a lecture in the U.K. in 2012 regarding transdisciplinary assessment, Lea presented a slide noting that the role of the optometrist is principally in function and optics, in contrast to the the ophthalmologist who primarily addresses anatomy and disease:
In lectures she has given, as well as in the epilogue to the 2nd edition of her book, Lea emphasizes that the ICD system is useful for defining visual impairment, but not for classifying visual functioning. For the latter, and for clinical purposes of intervention, the ICF (International Classification of Functioning, Disability, and Health, 2001), and its pediatric version, the ICF-CY (ICF for Children and Youth, 2007) is more pertinent. It seems as if there has been movement in this direction internationally with regard to collaboration between Medicine and Education (see this co-presentation from Dr. Hyvärinen and this 2018 publication from Frontiers in Education regarding disability research involving pre-schoolers).
The subtitle of Lea’s book is Assessment of Visual Functioning for Development and Learning, speaks volumes. Let’s take a look at some of the key concepts she embraces.
- Regarding fixations: “It is important to observe fixation and other oculomotor functions in situations that require concentration for looking at small or complex pictures and during reading. During these functions, fixations, saccades, and scanning eye movements should be automatic. If a child needs to consciously fixate and focus on a small target, these two simultaneous motor functions may demand too much of the child’s limited capacity and cause overload or lose head control … If reading from the black board or working on a near vision task requires too much motor capacity, posture control may be lost and the child lies flat on the desk. There should be a constant adjustment based on observation of the varying balance between the capacity for using vision and the capacity for postural control so the student can concentrate on his tasks.”
- Regarding saccades: “Some children have the greatest difficulties in controlling their eye movements when crossing the midline. Their eyes may close briefly at midline or there is a jerk in the following movement. This rarely reported phenomenon has been observed in children with ‘athetosis’ who often cannot use vision at midline.”
3. Regarding acuity, accommodation, convergence, and the need to consider plus lenses at near: “The sensory task is easier during the short measurement of visual acuity than during the reading of a text which may require so much brain capacity, the motor functions become irregular or weak. Observe the effects of reading glasses: how reading speed and errors in reading and comprehension of the content vary when the child reads with/ without reading glasses.” Lea also stresses the need to maintain balance between the intra-ocular muscles (controlling accommodation) and extra-ocular muscles (controlling versions and vergence), and the need to conduct dynamic retinoscopy on any child with developmental challenges.
4. Visual field as pertaining to reading: “During reading, several functions occur simultaneously. While reading a word, a visual map of the text is created. The map is instantly passed to planning of oculomotor functions in the executive command functions (in the frontal lobes), which get ready to activate the 12 eye muscles as soon as fixation is detached from the word.”
5. As pertains to the visual complexity of reading: “Reading is the most common problem in school referrals. It is a good example of numerous brain functions supporting a demanding task. Reading requires several simultaneous functions in the visual processing and in the visuomotor functions before the information can be used as language. In Chapter 2 we learned that fixation and saccades are more demanding than the conscious fixation and saccadic movements assessed during clinical examinations.”
6. Regarding trans-disciplinary collaboration: “Sometimes changes in motor functions are complex and require close collaboration between the doctors and the school to find optimal devices and ergonomic solutions. The educational resource centers together with the rehabilitation ophthalmologist, orthoptist, optometrist, rehabilitation team, and the school’s occupational and physiotherapists can tackle these problems which are difficult to treat at the hospitals because they lack the special knowledge on inclusive education.”
7. As related to #6: “Children with visual processing disorders may also have other problems in brain functions: in attention, executive functions, motor functions, and auditory processing functions. Many children have atypical peripheral functions in their eyes and ears. The assessment of these children’s many atypical functions and planning of early intervention and education should be supported by information from all medical specialties involved, optometry, and social services. With adequate support, children with complex problems in brain functions may develop, study well, and become the next generation of young workers who can provide first-hand information on what it means to grow and learn using atypical brain functions.”
8. With regard to the importance of communication: “Oculomotor functions can be observed after a short training, but the interpretations are often difficult. A perfect assessment is not the goal. The goal is to understand the information related to the child’s problems and to discuss the child’s functions and functioning at school. Doctors are becoming aware of the need to describe oculomotor functions better and describe behaviors that indicate a problem in oculomotor functions.”
9. Motion perception as related to neurology: “Visual information moves as magnocellular information via the retinal ganglion cell axons to the ‘superior colliculus’ in the tectum and the ‘pulvinar’ in the thalamus. Pulvinar connects to area V5 and through it but also directly to V1, V2, V3, and parietal cortex …The tectopulvinar pathway supports visual functions if the retinocalcarine pathway is damaged between LGN and V1 in the optic radiation, which is a common finding in brain damage around the ventricles. In this damage, form perception may be
lost but motion perception may function.”
10. As related to #9: “One of the typical unusual behaviors of children with poor motion perception is walking fast and bumping into large objects. If the child can perceive only very slow movement, objects in their side vision are blurred and uncomfortable when they move at their usual speed. Objects disappear completely if the speed is increased. When the “blurred tunnel” disappears, objects far away become visible because their relative speed is low. Since the objects close by are not seen, the child may bump into large objects and people. This is often misinterpreted as a sign of poor attention, but in reality, the child is functionally blind in relation to the objects he passes close by.
11. Regarding spatial awareness and orientation: “Perception of near and far space need to be assessed as separate functions. Some children function well in the small egocentric space and are quick in building puzzles. They seem to have no difficulties in solving three-dimensional puzzles (if they have good picture perception and recognition) but have major problems perceiving and remembering relationships in large allocentric spaces.”
12. Lea is a proponent of schools using pictures, numbers, on transparent film or plexiglass so that recordings can be made of eye hand accuracy in scanning and localizing, as well as head and eye position as the patient is responding.
Lea’s slim volume doesn’t follow a typical textbook format, and reads more like a hard-bound monograph. But it is well-organized for its purpose, and provides valuable videos as well as a copy of the complete text in its accompanying USB. At $99 for the hardback and thumb drive, it is a worthwhile investment.