Effects of visual search training in children with hemianopia.

BACKGROUND: This study investigates the effect of a new computer-based visual search training (VST) that was adapted for children with homonymous hemianopia (HH). METHODS: 22 children with HH (median age 11 years, 8 months: 6y6m-19y2m) trained at home for 15 minutes twice/day, 5 days/week, for 6 weeks. To assess performance before training (T1), directly after training (T2) and 6 weeks after the end of training (T3), we measured search times (STs) during on-screen search (with eye tracking), and in a real life search task. Additional variables analyzed during on-screen search were numbers, amplitudes, and durations of saccades, their directional patterns and the proportional number of saccades into the non-seeing field. The latter was the main variable during free viewing. Sixteen healthy age-matched children, who did not undergo the training, served as comparison group. Quality of Life (QoL)-questionnaires were also applied. RESULTS: STs of the patients decreased significantly during the training and all search performance tests. This improvement persisted 6 weeks after the end of the training. Saccade amplitudes increased, total number of saccades to find the target decreased, and the proportional number of saccades to the non-seeing side increased. These changes were maintained at T3. Saccade durations did not change. During free viewing, saccades were equally distributed to both sides before and after training. Patients reported improvements in QoL and activities of daily living. Performance in the healthy children did not change by simply repeating the visual search test. CONCLUSIONS: The improvement in STs in all search tasks, larger and fewer saccades, and an improved search strategy after VST suggests that the children with HH benefited from the training. The maintained improvement at T3 and the improvement in the real life search task indicate that the newly developed search strategy persists and can be applied to everyday life.

Homonymous Hemianopia in Children and Adolescents: An MRI Study.

AIM: Diagnosing homonymous hemianopia (HH) in children can be difficult due to inability to comply with perimetry. Therefore, HH can often only be suspected by magnetic resonance imaging (MRI) showing lesions to the retrochiasmatic visual pathways. The aim of our retrospective observational cross-sectional study was to improve the radiologic detection of HH. METHODS: MRIs of 21 subjects (5-17 years old) with ophthalmologically confirmed HH (14 complete, 7 incomplete hemianopias) were analyzed. In addition, we asked four questions looking at everyday problems possibly related to the HH. The questions asked for (1) problems in avoiding objects/people, (2) bumping into objects/people, (3) difficulties in judging stairs, and (4) difficulties in grasping objects. RESULTS: We found neuroanatomical correlates of the HH in all 21 participants, with the optic radiation being involved in almost all participants (20/21). Everyday problems possibly related to the HH were reported for all nine patients with postneonatally acquired complete hemianopias. In contrast, no such problems were reported for seven patients with incomplete HH (7/7) and for 3/5 patients with complete hemianopias due to pre-, peri- or neonatally acquired brain lesions. INTERPRETATION: A dedicated radiologic analysis of the retrochiasmatic optic pathway should routinely be performed in children with brain lesions to identify children with HH. Early onset and incomplete HH are predictors for successful compensation.

Training the adult amblyopic eye with "perceptual learning" after vision loss in the non-amblyopic eye.

We recently reported acuity development in the amblyopic eye of a 60-year-old patient after loss of vision in her non-amblyopic eye. Here, we focus on the training that we implemented, based on new insights from psychophysical procedures aiming at functional visual improvement of adults ("perceptual learning"). We alternately used the following procedures: grating acuity (Teller-Cards); contrast sensitivity (Vistech-Charts); two spatial localization tests (vertical alignment, pointing); and labyrinth patterns for a eye-hand coordination exercise. One month without intervention was followed by six months of training and two blocks of pleoptic treatment. Clinical parameters were assessed monthly. Besides acuity gain, we observed enhanced grating resolution and contrast sensitivity, decreased alignment distortions, pointing shifts, mainly after pleoptics, and more efficient labyrinth tracing. A questionnaire reflected the patient's perception of the changes. These data confirm the plasticity of the adult amblyopic system, be it spontaneous due to the loss of the non-amblyopic eye or caused by the intervention or both. Further experience is necessary to isolate the role of the intervention. Our results also underline the limitation of adult plasticity, emphasizing the importance of early diagnosis and treatment of amblyopia.

Visual improvement during psychophysical training in an adult amblyopic eye following visual loss in the contralateral eye.

BACKGROUND: Recent publications have demonstrated neural plasticity in adult amblyopes subjected to psychophysical training based on perceptual learning. The purpose of this case report is to present rarely available prospective data of visual acuity development in a strabismic amblyope undergoing psychophysical training and pleoptic treatment after loss of function of the non-amblyopic eye. METHODS: The design is a prospective, observational and interventional case report. Visual acuity was tested monthly, with constant optical correction. The 60-year-old female patient participated in a psychophysical training implemented in our laboratory, and in pleoptic treatment. RESULTS: Slow functional improvement of the amblyopic eye was observed during a period of 10 months, both in the tests used for training and in visual acuity: single optotypes increased by 4 chart lines, crowded optotypes by 2-3 lines. CONCLUSIONS: To our knowledge, this is the first report of the new approach of perceptual learning in an adult amblyope after loss of vision in the contralateral eye. Our results represent further evidence that the visual system of adult amblyopes preserves a certain degree of neural plasticity, whether spontaneous or enhanced by training. Furthermore, that plasticity in adults is limited, and early diagnosis and treatment of amblyopia must remain the primary goal.