Sacrificing one visual hemifield during pediatric epilepsy surgery: Effects on visual search.

OBJECTIVES: To investigate early and late effects of planned surgically acquired homonymous hemianopias on visual search in children and adolescents. METHODS: This prospective study included five patients (5y 5 m-18y 0 m; 2 girls) with pharmaco-refractory epilepsies in whom one visual hemifield was sacrificed as part of the surgical strategy, and, as controls, seven patients (5y 11 m-18y 0 m; 6 girls) undergoing epilepsy surgeries not affecting the visual fields. Visual search was studied using the "Table Test", which is an everyday life-like visual search test. General processing speed was studied using a standard IQ subtest. RESULTS: All five patients with newly acquired homonymous hemianopias showed a relative disadvantage of visual search times for objects in their newly blind hemifields immediately after the surgery. Six months later, this relative disadvantage had recovered completely in all patients. Nevertheless, compared with the preoperative situation, overall search times were still prolonged in the hemianopic patients, but this effect could be mitigated or even overcompensated by improvements in processing speed. CONCLUSIONS: Children with homonymous hemianopias inflicted by epilepsy surgery develop effective compensation strategies to minimize the relative disadvantage of visual search in their blind hemifields. For changes in overall visual search times between the preoperative and the six-month follow-up examination, we could demonstrate overlapping effects of (a) deterioration by hemianopia and (b) amelioration by improved processing speed as part of the cognitive improvements achieved by amelioration of the epilepsy.

Uncovering homonymous visual field defects in candidates for pediatric epilepsy surgery.

OBJECTIVES: Perimetry in children can be challenging due to low cooperation and short attention span. Especially during the pre-surgical work-up of children with pharmaco-refractory epilepsies, however, diagnosing homonymous visual field defects (HVFDs) can be crucial for planning surgical strategies. Here, we evaluated "campimetry" for visual field testing in children. Furthermore, we analyzed strabismus and anomalous head posture as clinical signs for HVFDs. METHODS: Campimetry and a standard orthoptic examination were performed in 18 patients (age range: 3 y 2 m-18 y) who underwent epilepsy surgeries in our center during the study period, and in 11 additional patients (age range: 2 y 10 m-22 y 10 m) with suspected or confirmed HVFDs. RESULTS: In 16/18 patients of our unselected surgery cohort, pre- and postoperative campimetry was successfully completed. Of these, only 7/16 patients had intact visual fields pre- and postoperatively, while 5/16 patients already showed preoperative HVFDs and 4/16 patients suffered newly acquired HVFDs as calculated consequences of the surgery. Regarding clinical signs, strabismus (mostly esotropia) and anomalous head posture were specific indicators of HVFDs (strabismus: 6/12 with HVFDs vs 1/18 without; anomalous head posture: 8/12 with HVFDs vs 0/18 without). CONCLUSIONS: For perimetry in children with limited cooperation, we suggest campimetry as it allows early detection and fast delineation of HVFDs. This is particularly important in pediatric epilepsy surgery patients, who display a surprisingly high proportion of HVFDs (9/16). Both, strabismus and anomalous head posture can indicate such HVFDs. Therefore, clinicians should pay attention to these clinical signs, especially in the context of epilepsy surgery.

Macular pigment and fixation after macular translocation surgery.

BACKGROUND: After full macular translocation (MT) surgery with 360 degrees retinotomy, the fovea is rarely identifiable. Our aim was to verify the position of the fovea, to determine how patients fixate after MT and to examine distribution and optical density of macular pigment (MP). METHODS: 9 patients after MT were investigated. The Utrecht Macular Pigment Reflectometer was used to quantify the MP optical density. A scanning laser ophthalmoscope (SLO) was used to identify the fovea as the centre of MP distribution and determine the retinal locus of fixation. RESULTS: In all patients, the fovea was identified as the centre of MP distribution. The retinal areas used for fixation were displayed by SLO fixation analysis. Comparing their spatial relationship with the fovea, five patients fixated centrally and four eccentrically up to 7.5 degrees . In those patients, microperimetry showed that the atrophy caused by choroidal neovascularisation (CNV) extraction prevented central fixation. CONCLUSION: The combination of MP distribution and fixation analysis allows fixation behaviour to be quantified, even if the fovea morphologically cannot be localised. Our results suggest that the scotoma caused by spreading chorioretinal atrophy is the main cause for reduced visual acuity after MT, and so the MT rotation angle is crucially important.

Parafoveal letter recognition at reduced contrast in normal aging and in patients with risk factors for AMD.

BACKGROUND: Patients with early age-related maculopathy (ARM) do not necessarily show obvious morphological signs or functional impairment. Many have good visual acuity, yet complain of decreased visual performance. The aim of this study was to investigate the aging effects on performance of parafoveal letter recognition at reduced contrast, and defects caused by early ARM and normal fellow eyes of patients with unilateral age-related macular degeneration (nfAMD). METHODS: Testing of the central visual field (8 degrees radius) was performed by the Macular Mapping Test (MMT) using recognition of letters in 40 parafoveal target locations at four contrast levels (5, 10, 25 and 100%). Effects of aging were investigated in 64 healthy subjects aged 23 to 76 years (CTRL). In addition, 39 eyes (minimum visual acuity of 0.63;20/30) from 39 patients with either no visible signs of ARM, while the fellow eye had advanced age-related macular degeneration (nfAMD; n = 12), or early signs of ARM (eARM; n = 27) were examined. Performance was expressed summarily as a "field score" (FS). RESULTS: Performance in the MMT begins to decline linearly with age in normal subjects from the age of 50 and 54 years on, at 5% and 10% contrast respectively. The differentiation between patients and CTRLs was enhanced if FS at 5% was analyzed along with FS at 10% contrast. In 8/12 patients from group nfAMD and in 18/27 from group eARM, the FS was statistically significantly lower than in the CTRL group in at least one of the lower contrast levels. CONCLUSION: Using parafoveal test locations, a recognition task and diminished contrast increases the chance of early detection of functional defects due to eARM or nfAMD and can differentiate them from those due to aging alone.

Textos padronizados em português (BR) para medida da velocidade de leitura: comparação com quatro idiomas europeus / New standardized texts in Brazilian Portuguese to assess reading speed: comparison with four European languages

OBJETIVO: Desenvolver textos para medida da velocidade de leitura comparáveis com outros quatro idiomas europeus. MÉTODOS: Dez textos com similar grau de dificuldade, número de caracteres, número de palavras e sintaxe (segundo a teoria de Gibson) foram desenvolvidos por um especialista em lingüística, em português (BR), fazendo-se a tradução de textos previamente padronizados em quatro idiomas: inglês, francês, finlandês e alemão. A velocidade de leitura foi medida em 25 indivíduos saudáveis de idade entre 19 e 35 anos (mediana=24 anos) com os dez textos. RESULTADOS: A velocidade de leitura nos textos em português foi em média 1100 ± 167 (desvio padrão) caracteres por minuto. Pequenas diferenças foram encontradas entre as velocidades de leitura medidas com os dez textos, e essas diferenças não foram estatisticamente significantes em grupos de no mínimo seis textos. A velocidade de leitura dos voluntários da mesma faixa etária nos outros idiomas foi: alemão: 1126 ± 105; finlandês: 1263 ± 142; francês: 1214 ± 152 e inglês: 1234 ± 147. CONCLUSÃO: Os autores desenvolveram um conjunto de textos em português (BR) padronizados e homogêneos para medida da velocidade de leitura, que são comparáveis com textos em outros quatro idiomas europeus. Esses textos podem ser usados para estudos multicêntricos internacionais envolvendo leitura e visão subnormal.

PURPOSE: To develop standardized texts in Brazilian Portuguese to assess reading speed and compare performances among four European languages. METHODS: 10 texts were designed by a linguistic expert at the level of a sixth grade reading material (reading ages 10-12 years) and were matched for length and syntactic complexity, according to the syntactic prediction locality theory of Gibson. Normally sighted native speaking volunteers aged 18-35 years read each text aloud at random. RESULTS: The reading speed was on average 1100 ± 167 (standard deviation) characters per minute. Only small differences were found between the measured reading speeds of the 10 texts, and these differences were not statistically significant in groups of at least 6 texts. The mean reading speed in age-matched volunteers in Finnish was: 1263 ± 142; French: 1214 ± 152; English: 1234 ± 147; and German: 1126 ± 105. CONCLUSIONS: The authors developed a set of standardized, homogeneous, and comparable texts in Brazilian Portuguese. These texts will be a valuable tool to measure reading speed for repeated measurements and in international studies in the field of reading and low vision research.

Reading performance with low-vision aids and vision-related quality of life after macular translocation surgery in patients with age-related macular degeneration.

PURPOSE: The aim of the present study was to evaluate the power of magnification required, reading performance with low-vision aids and vision-related quality of life with reference to reading ability and ability to carry out day-to-day activities in patients after macular translocation. METHODS: This study included 15 patients who had undergone macular translocation with 360-degree peripheral retinectomy. The mean length of follow-up was 19.2 +/- 10.8 months (median 11 months). At the final examination, the impact of visual impairment on reading ability and quality of life was assessed according to a modified 9-item questionnaire in conjunction with a comprehensive clinical examination, which included assessment of best corrected visual acuity (BCVA), the magnification power required for reading, use of low-vision aids and reading speed. Patients rated the extent to which low vision restricted their ability to read and participate in other activities that affect quality of life. Responses were scored on a scale of 1.0 (optimum self-evaluation) to 5.0 (very poor). RESULTS: In the operated eye, overall mean postoperative BCVA (distance) was not significantly better than mean preoperative BCVA (0.11 +/- 0.06 and 0.15 +/- 0.08, respectively; p = 0.53). However, 53% of patients reported a subjective increase in visual function after treatment. At the final visit, the mean magnification required was x 7.7 +/- 6.7. A total of 60% of patients needed optical magnifiers for reading and in 40% of patients closed-circuit TV systems were necessary. All patients were able to read newspaper print using adapted low-vision aids at a mean reading speed of 71 +/- 40 words per minute. Mean self-reported scores were 3.2 +/- 1.1 for reading, 2.5 +/- 0.7 for day-to-day activities and 2.7 +/- 3.0 for outdoor walking and using steps or stairs. Patients' levels of dependency were significantly correlated with scores for reading (p = 0.01), day-to-day activities (p < 0.001) and outdoor walking and using steps (p = 0.001). CONCLUSIONS: The evaluation of self-reported visual function and vision-related quality of life in patients after macular translocation is necessary to obtain detailed information on treatment effects. Our results indicated improvement in patients' subjective evaluations of visual function, without significant improvement in visual acuity. The postoperative clinical benefits of treatment coincide with subjective benefits in terms of reading ability, quality of life and patient satisfaction. Our study confirms the importance and efficiency of visual rehabilitation with aids for low vision after surgery.