Neurogenic vision loss: Causes and outcome. An experience from a tertiary center in Northern India

Optic canal characteristics in pediatric syndromic craniosynostosis

The aim of this study was to compare optic canal parameters of syndromic craniosynostosis patients with those of normal patients to visit the possibility of optic nerve impingement as a cause of visual impairment. Computed tomography scan images were processed using the Materialise Interactive Medical Image Control System (MIMICS) Research 21.0 software (Materialise NV, Leuven, Belgium). Eleven optic canal parameters were measured: 1) height of optic canal on the cranial side, 2) height of optic canal on the orbital side 3) length of the medial wall of the optic canal, 4) length of the lateral canal wall of the optic canal, 5) diameter of the optic canal at five points (Q1-Q4 and mid canal), and 6) area and perimeter of optic canal. These measurements were obtained for both the right and left optic canals. The study sample comprised four Crouzon syndrome, five Apert syndrome, and three Pfeiffer syndrome patients. The age of these syndromic craniosynostosis patients ranged from 2 to 63 months. The height of the optic canal on the orbital side (p = 0.041), diameter of the mid canal (p = 0.040), and diameter between the mid-canal and the cranial opening (Q3) (p = 0.079) for syndromic craniosynostosis patients were statistically narrower compared with those of normal patients when a significance level of 0.1 was considered. Scatter plots for the ages of patients versus the above parameters gave three separated clusters that suggested the arresting of optic canal development with age. The findings from this study demonstrated a narrowing of the optic canal in syndromic craniosynostosis patients, and indicate that optic canal anatomical characteristics may have an association with visual impairment among pediatric syndromic craniosynostosis patients.

Optic Canal Analysis in Syndromic Craniosynostosis: Volumetric and Surface Area Validation Study Using Different Measurement Modalities

BACKGROUND

In syndromic craniosynostosis (SC), unlike persistent corneal irritation due to severe exophthalmos and increased intracranial pressure, optic canal (OC) stenosis has been scarcely reported to cause visual impairment. This study aimed to validate the OC volumetric and surface area measurement among SC patients.

METHODS

Sixteen computed tomography scan of SC patients (8 months-6 years old) were imported to Materialise Interactive Medical Image Control System (MIMICS) and Materialise 3-matics software. Three-dimensional (3D) OC models were fabricated, and linear measurements were obtained. Mathematical formulas were used for calculation of OC volume and surface area from the 3D model. The same measurements were obtained from the software and used as ground truth. Data normality was investigated before statistical analyses were performed. Wilcoxon test was used to validate differences of OC volume and surface area between 3D model and software.

RESULTS

The mean values for OC surface area for 3D model and MIMICS software were 103.19 mm2 and 31.27 mm2, respectively, whereas the mean for OC volume for 3D model and MIMICS software were 184.37 mm2 and 147.07 mm2, respectively. Significant difference was found between OC volume (P = 0.0681) and surface area (P = 0.0002) between 3D model and software.

CONCLUSION

Optic canal in SC is not a perfect conical frustum thus making 3D model measurement and mathematical formula for surface area and volume estimation not ideal. Computer software remains the best modality to gauge dimensional parameter and is useful to elucidates the relationship of OC and eye function as well as aiding intervention in SC patients.

Retinal sublayer defect is independently associated with the severity of hypertensive white matter hyperintensity

PURPOSE

To investigate the association of specific retinal sublayer thicknesses on optical coherence tomography (OCT) imaging with brain magnetic resonance imaging (MRI) markers using the Fazekas scale in hypertensive white matter hyperintensity (WMH) subjects.

METHODS

Eighty-eight participants (32 healthy controls and 56 hypertensive white matter hyperintensity subjects) underwent retinal imaging using the OCT and MRI. A custom-built algorithm was used to measure the thicknesses of the retinal nerve fiber layer (RNFL) and ganglion cell layer and inner plexiform layer (GCIP). Focal markers for white matter hyperintensities were assessed on MRI and graded using the Fazekas visual rating.

RESULTS

Hypertensive WMH showed significantly reduced (p < .05) RNFL and GCIP layers when compared to healthy controls, respectively. A significant correlation was found between the RNFL (ρ = -.246, p < .001) and GCIP (ρ = -.338, p < .001) of the total participants and the Fazekas score, respectively. Statistical differences were still significant (p < .05) when correlations were adjusted for intereye correlation, age, hypertension, smoking, body mass index, and diabetes. Among the cases of hypertensive WMH, higher Fazekas scores were significantly associated (p < .05) with the thinning of both the RNFL and GCIP layers after adjustment of age and other risk factors.

CONCLUSIONS

Retinal degeneration in the RNFL and GCIP was independently associated with focal lesions in the white matter of the brain and deteriorates with the severity of the lesions. We suggest that imaging and measurement of the retinal sublayers using the OCT may provide evidence on neurodegeneration in WMH.

Neuro-Ophthalmology at the Bedside: A Clinical Guide

Neuro-ophthalmological signs and symptoms are common in the emergency department but are a frequent source of diagnostic uncertainties. However, neuro-ophthalmological signs often allow a precise neuro-topographical localization of the clinical problem. A practical concept is presented how to perform a neuro-ophthalmological examination at the bedside and to interpret key findings under the aspect of emergency medicine with limited resources.

Etiology of optic atrophy: a prospective observational study from Saudi Arabia

BACKGROUND

Optic atrophy (OA) represents permanent retinal ganglion cell loss warranting study to establish etiology.

OBJECTIVES

To describe neurogenic causes of OA.

DESIGN

Prospective, observational.

SETTING

Tertiary care center, Riyadh, Saudi Arabia.

PATIENTS AND METHODS

We included consecutive patients of all ages with OA caused by lesions affecting the visual pathways who were referred over a 9-month period (November 2013 to July 2014). Diagnosis was based on visual acuity, ophthalmoscopic features and ancillary tests. Patient demographics, results of a clinical examination, test data and etiology were recorded. For each cause of OA, both gender and age group were analyzed as potential risk factors using simple univariate logistic regression. OA associated with glaucoma and retinal diseases was excluded.

MAIN OUTCOME MEASURE

Description of causes of OA.

RESULTS

Two hundred and four patients and 353 eyes met inclusion criteria. The median age was 27 years (range 3 months-77 years; interquartile range, 27 years) among 111(54.4%) females and 93(45.6%) males, with no statistically significant difference in age of presentation between the genders. The majority of lesions were bilateral (n=151, 74%). Tumors were the most common cause, accounting for 127 (62.2%) cases. These occurred mostly in adults (72.4%) compared to the pediatric group (OR=3.3, 95% CI: 1.79-6.03; P < .001). Hereditary neoplasia (OR=5.55; 95% CI: 1.67-18.42; P=.005) and metabolic diseases (OR=17.57; 95% CI: 2.15-143.62; P=.007) were more common causes in the pediatric group. There were no significant associations between gender or visual acuity and etiology of OA. In developed nations, OA is frequently the result of ischemia and neuritis. We found many other causes, especially orbital and intracranial tumors.

CONCLUSIONS

The frequency of tumors as the cause of OA may represent a higher incidence of aggressive tumors coupled with poor recognition/acknowledgement of symptoms and limited access, resulting in late presentations.

LIMITATIONS

These findings may reflect bias from selective referrals to a tertiary center and may not represent all of Saudi Arabia.