The aim of this work was to measure susceptibility to pattern glare within a stroke group, employing a direct method of assessment. Twenty stroke subjects, aged 38–85 years, were recruited, along with an age-matched control group (n = 20). Assessment of pattern glare susceptibility was undertaken using the pattern glare test. An abnormal degree of pattern glare is present when individuals score >1 on the mid-high spatial frequency difference variable, a relative score that allows for normalization of the subject, or >3 when viewing the mid spatial frequency grating. Stroke subjects demonstrate elevated levels of pattern glare compared to normative data values and a control population, as determined using the pattern glare test. This was most notable when considering the output measure for the mid-high difference variable. The mean score for the mid-high difference variable was 2.15 SD 1.27 for the stroke subjects versus 0.10 SD 1.12 for the control subjects. When considering the mid-high difference variable, 75% of the stroke group recorded an abnormal level of pattern glare compared to 5% in the control group. This study demonstrates an association between stroke subjects and elevated levels of pattern glare. Cortical hyperexcitability has been shown to present following stroke, and this has been proposed as a plausible explanation for the perceptual distortions experienced by individuals susceptible to pattern glare. Further work to assess the benefits of spectral filters in reducing perceptual distortions in stroke patients is currently underway.

Purpose. To examine the influence of positional misalignments on intraocular pressure (IOP) measurement with a rebound tonometer. Methods. Using the iCare rebound tonometer, IOP readings were taken from the right eye of 36 healthy subjects at the central corneal apex (CC) and compared to IOP measures using the Goldmann applanation tonometer (GAT). Using a bespoke rig, iCare IOP readings were also taken 2 mm laterally from CC, both nasally and temporally, along with angular deviations of 5 and 10 degrees, both nasally and temporally to the visual axis. Results. Mean IOP ± SD, as measured by GAT, was 14.7 ± 2.5 mmHg versus iCare tonometer readings of 17.4 ± 3.6 mmHg at CC, representing an iCare IOP overestimation of 2.7 ± 2.8 mmHg (P < 0.001), which increased at higher average IOPs. IOP at CC using the iCare tonometer was not significantly different to values at lateral displacements. IOP was marginally underestimated with angular deviation of the probe but only reaching significance at 10 degrees nasally. Conclusions. As shown previously, the iCare tonometer overestimates IOP compared to GAT. However, IOP measurement in normal, healthy subjects using the iCare rebound tonometer appears insensitive to misalignments. An IOP underestimation of <1 mmHg with the probe deviated 10 degrees nasally reached statistical but not clinical significance levels.

To establish whether axial growth and refractive error can be modulated in hyperopic children by imposing relative peripheral hyperopic defocus using multifocal soft contact lenses. Methods:A prospective controlled study with hyperopic participants allocated to a control or test group. Control group participants were corrected with single vision spectacles and changes to axial length and refractive error were followed for 3 years. For the test group, axial growth and post-cycloplegic refractive error were observed with participants wearing single vision spectacles for the first 6 months of the trial and then corrected with centre-near multifocal soft contact lenses with a 2.00 D add for 2 years. The central 'near' portion of the contact lens corrected distance refractive error while the 'distance' portion imposed hyperopic defocus.Participants reverted to single vision spectacles for the final 6 months of the study.Results: Twenty-two participants, mean age 11.13 years (SD 1.72) (range 8.33-13.92), completed the trial. Axial length did not change during the first 6 months in either group (p = 1.00). Axial growth across the 2-year intervention period was 0.17 mm (SEM 0.04) (p < 0.0005) in the test group versus 0.06 mm (SEM 0.07) (p = 0.68) in the control group. Axial length was invariant during the final 6 months in either group (p = 1.00). Refractive error was stable during the first 6 months in both groups (p = 1.00). Refractive error change across the 2-year intervention period was −0.26 D (SEM 0.14) (p = 0.38) in the test group versus −0.01 D (SEM 0.09) (p = 1.00) in the control group. Neither the test (p = 1.00) nor control (p = 0.63) group demonstrated a change in refractive error during the final 6 months. Conclusions: The rate of axial growth can be accelerated in children with hyperopia using centre-near multifocal soft contact lenses. K E Y W O R D S axial growth, contact lenses, hyperopia, peripheral defocus, refractive error | 535 EFFECT OF DEFOCUS ON AXIAL GROWTH IN HYPEROPES F I G U R E 1 Schematic to demonstrate the concept of relative peripheral hyperopic defocus (RPHD) imposed with a centre-near bifocal contact lens (CL), while full refractive error is corrected centrally

Purpose: The aim of the study was to determine the effect of optimal spectral filters on reading performance following stroke. Methods: Seventeen stroke subjects, aged 43---85, were considered with an age-matched Control Group (n = 17). Subjects undertook the Wilkins Rate of Reading Test on three occasions: (i) using an optimally selected spectral filter; (ii) subjects were randomly assigned to two groups: Group 1 used an optimal filter, whereas Group 2 used a grey filter, for two-weeks. The grey filter had similar photopic reflectance to the optimal filters, intended as a surrogate for a placebo; (iii) the groups were crossed over with Group 1 using a grey filter and Group 2 given an optimal filter, for two weeks, before undertaking the task once more. An increase in reading speed of >5% was considered clinically relevant. Results: Initial use of a spectral filter in the stroke cohort, increased reading speed by ∼8%, almost halving error scores, findings not replicated in controls. Prolonged use of an optimal spectral filter increased reading speed by >9% for stroke subjects; errors more than halved. When the same subjects switched to using a grey filter, reading speed reduced by ∼4%. A second group of stroke subjects used a grey filter first; reading speed decreased by ∼3% but increased by ∼4% with an optimal filter, with error scores almost halving. Conclusions: The present study has shown that spectral filters can immediately improve reading speed and accuracy following stroke, whereas prolonged use does not increase these benefits significantly.Effect of spectral filters on reading following stroke 135 PALABRAS CLAVEIctus; Rehabilitación visual; Filtros espectrales; Hiper-excitabilidad cortical; Reflejo patrón Efecto de los filtros espectrales en la velocidad y precisión de lectura tras un ictus ResumenObjetivo: El objetivo de estudio fue la determinación del efecto de filtros espectrales óptimos sobre el rendimiento lector tras ictus cerebral. Métodos: Se evaluó a diecisiete pacientes tras ictus cerebral, con edades comprendidas entre 43 y 85 años, junto con un grupo de control con edades equivalentes (n = 17). Los pacientes realizaron en tres ocasiones la prueba de lectura Wilkins: (i) utilizando un filtro espectral ópti-mamente seleccionado; (ii) distribuyendo a los pacientes en dos grupos al azar: el Grupo 1 utilizó un filtro óptimo, mientras que el Grupo 2 utilizó un filtro gris, durante dos semanas. El filtro gris tenía una reflectancia fotópica similar a la de los filtros óptimos, con intención de actuar como placebo; (iii) se cruzaron los grupos de modo que en el Grupo 1 se utilizó un filtro gris, entregándose al Grupo 2 un filtro óptimo durante dos semanas, antes de volver a realizar la operación. Se consideró clínicamente relevante un incremento de la velocidad de lectura de >5%. Resultados: El uso inicial de un filtro espectral en la población de pacientes con ictus incrementó la velocidad de lectura en un ∼8%, reduciendo casi a la mitad las puntuaciones de error no replicándose los hallazgos en l...

Visual stress is a condition characterised by symptoms of eyestrain, headaches and distortions of visual perception when reading text. The symptoms are frequently alleviated with spectral filters and precision tinted ophthalmic lenses. Visual stress is thought to arise due to cortical hyperexcitability and is associated with a range of neurological conditions. Cortical hyperexcitability is known to occur following stroke. The case presented describes visual stress symptoms resulting from stroke, subsequently managed with spectral filters and precision tinted ophthalmic lenses. The case also highlights that the spectral properties of the tint may need to be modified if the disease course alters.