Binocular vision interference from unequal inputs in an adult patient with monocular dense acquired cataract.

INTRODUCTION: The effect of the unequal visual inputs in uniocular cataracts is addressed through the hypothesis that a marked inequality of the visual inputs will have an interference effect that will degrade the binocular vision relative to that of the better eye. We tested this hypothesis of reverse interference effect by both clinical and functional Magnetic Resonance Imaging assessments in an acute unilateral cataract patient. The patient was 63 year old woman who rapidly developed a dense sub-capsular cataract following steroid radio-chemotherapy treatment for breast cancer. METHODS: Clinical: Ophthalmologic evaluation and distance visual acuity (both uniocular and binocular), contrast sensitivity, binocular function, ocular motility and cover test to evaluate the presence of strabismus, and a slit lamp assessment of cataract density were performed. Neuroimaging: Functional MRI was run in a 1.5T Philips Intera Master with a SENSE neurovascular coil of 8 channels. The experimental design included three conditions: a) Binocular: both eyes viewing; b) OS-mono: left eye viewing, right eye occluded by a black cover; c) OD-mono: right eye viewing, left eye occluded by a black cover. RESULTS: Clinical: The logMAR visual acuity was 0.9 OD, hand movement at one meter OS, and 0.7 for binocular viewing, that is, the binocular acuity was worse than the better eye acuity alone. As hypothesized, adding a diffuser lens and a penlight glare on the cataract eye increased the interference signal from that eye, and thus further reduced the binocular acuity to 0.4. Binocular contrast sensitivity also was worse than the OD alone. Neuroimaging: The fMRI results were consistent with the clinical findings. The number of activated voxels in the visual cortex under binocular viewing was reduced by about 40 percent relative to that for the fellow eye alone. CONCLUSION: Clinical and fMRI data were well-correlated and consistent with the prediction for the marked binocular asymmetry. The results imply that the mechanisms operating under a severe binocular vision asymmetry caused by unilateral diffusion (blur without contour perception, or light perception only) exhibit an interference effect under binocular viewing that is not seen in the case of weaker asymmetry such as in functional amblyopia, or from the extreme case of total elimination of visual input from one eye, such as in occlusion or monocular blindness.

The use of trypan blue dye for strabismus reoperations, surgery complications, and especially for the identification and recovery of a "slipped" or "lost" extraocular muscle.

PURPOSE: To evaluate trypan blue dye in strabismus surgery for tissue identification, to find the lowest optimal concentration, and to describe histological findings. in tissue so stained. METHODS: Trypan Blue dye 0.1% was serially diluted and tested by tissue staining at progressively different concentrations. Fifteen patients were studied using the dye. RESULTS: Trypan Blue 0.1 percent was the optimal concentration. Muscle, tendon and fibrotic tissues were easily identified and distinguished with the dye at this concentration. Such tissue identification was most useful and enhanced the performance of strabismus surgical operations, and especially in identifying and retrieving slipped or temporarily lost extraocular muscles.Also a thin basement-like membrane surrounding the superior oblique muscle tendons was disclosed with PAS stain, suggesting the presence of glycosaminoglycans. CONCLUSIONS: Trypan Blue 0.1percent contrasts the different tissues, dying the muscle sheath, tendons and fibrotic tissues, but not staining the sclera and muscle fibers per se.

Is one eye better than two in strabismus? Or does the misaligned amblyopic eye interfere with binocular vision? A preliminary functional MRI study.

PURPOSE: The aim of this study was to determine if patients with strabismic amblyopia could have increased occipital visual cortex activation with monocular stimulation of the sound fixing eye, rather than with simultaneous stimulation of both eyes. METHODS: A prospective study was performed including 12 patients with strabismus and amblyopia, who were evaluated using functional MRI with visual stimulation paradigms. The measurements were made in the occipital visual cortex, assessing the response to the binocular and monocular stimulation. RESULTS: 12 out of 12 patients showed an increased cortical response of the healthy eye in comparison to the amblyopic one. Nine of the 12 patients showed larger cortical activation with visual stimulation of the healthy eye compared to the binocular condition analysis. Three out of the 12 cases had a greater activation area when the stimulation was binocular rather than monocular, 2 of whom had a relatively small angle of strabismus. CONCLUSIONS: Patients with amblyopia and strabismus could see better with only one eye instead of both eyes. This could be related to inhibition of the binocular function of the brain by the misaligned amblyopic eye.

Superior oblique muscle MRI asymmetry and vertical deviation in patients with unilateral superior oblique palsy.

PURPOSE: To evaluate the MRI cross sectional greater area of the unilateral superior oblique (SO) muscle in patients with congenital or acquired superior oblique palsy to detect asymmetries and to determine if there is any relationship between the degree of vertical deviation and the muscle size determined by imaging. METHODS: Magnetic Resonance Imaging coronal images were obtained in primary position, supraversion and infraversion. Interocular differences and intergroup differences were compared in 17 patients with unilateral acquired or congenital SO palsy and 15 orthotropic control subjects. RESULTS: Mean maximal difference was 3.56 +/-0.83 mm(2) (p 0.01) between healthy and paretic eye in the paretic group, and 1.08 +/-0.40 mm(2) (p 0.02) in the control group. Statistical Intergroup comparison was p 0.02 (conventionally statistically significant). In 9 patients the maximal interocular difference was detected in 44.4% in infraversion, 33.3% indistinctly in supra- and infraversion and 22.2% in primary position. The correlation coefficient between vertical deviation and interocular asymmetry was not conventionally statistically significant at p>0.05. CONCLUSIONS: Patients with unilateral superior oblique palsy showed significant MRI asymmetry, which was represented by a relatively greater healthy SO muscle size, in the paretic congenital group. We found no association between the SO muscle size and the degree of any vertical deviation present.

Glaucoma en trasplantados renales pediátricos y su asociación con corticoides sistémicos y HLA / Glaucoma in pediatric renal transplant patients and its association with systemic steroids and HLA

Objetivo: determinar la presencia de glaucoma en trasplantados renales pediátricos y su asociación con la administración de corticoides y HLA. Métodos: se incluyeron 32 pacientes, a quienes se les realizó curva de presión ocular, campo visual computado, tomografía confocal del nervio óptico y examen con lámpara de hendidura. Resultados: se observó glaucoma en el 21.88 por ciento de los pacientes estudiados. La dosis total media de corticoide administrada fue de 13.73g. Se encontró una asociación, aunque estadísticamente no significativa, entre glaucoma y la dosis total de corticoides administrada (p=0,335), la dosis/kg-peso (p=0,470), el tiempo de tratamiento (p=0.203) y HLA. Conclusión: si bien existe una relación entre el tratamiento con corticoides y la presencia de glaucoma en los pacientes pediátricos con trasplante renal, no encontramos una asociación significativa entre glaucoma y los parámetros estudiados

Glaucoma en trasplantados renales pediátricos y su asociación con corticoides sistémicos y HLA / Glaucoma in pediatric renal transplant patients and its association with systemic steroids and HLA

Objetivo: determinar la presencia de glaucoma en trasplantados renales pediátricos y su asociación con la administración de corticoides y HLA. Métodos: se incluyeron 32 pacientes, a quienes se les realizó curva de presión ocular, campo visual computado, tomografía confocal del nervio óptico y examen con lámpara de hendidura. Resultados: se observó glaucoma en el 21.88 por ciento de los pacientes estudiados. La dosis total media de corticoide administrada fue de 13.73g. Se encontró una asociación, aunque estadísticamente no significativa, entre glaucoma y la dosis total de corticoides administrada (p=0,335), la dosis/kg-peso (p=0,470), el tiempo de tratamiento (p=0.203) y HLA. Conclusión: si bien existe una relación entre el tratamiento con corticoides y la presencia de glaucoma en los pacientes pediátricos con trasplante renal, no encontramos una asociación significativa entre glaucoma y los parámetros estudiados