Diagnosis of night blindness through standardized interview and electroretinography.

INTRODUCTION: Objective: To compare the diagnosis of NB through the use of the standardized interview of the World Health Organization/Pan American Health Organization (WHO/PAHO) with electroretinography, and also to evaluate the association of these diagnoses with serum concentrations of retinol in class III obesity individuals. Methods: Adult patients of both genders, in the 20-60 age group, with BMI ≥ 40 kg/m² were studied. NB was diagnosed through electroretinography and the standardized interview validated by the WHO/PAHO. Serum level of retinol was quantified by the HPLC-UV method, and VAD was diagnosed when levels were <1.05 µmol /L, and severity was also evaluated. Statistical analysis was carried out through the Statistical Package for the Social Sciences, version 21.0 (p < 0.05). Results: Mean BMI was 44.9  11.8 kg/m², and a negative correlation was found in serum levels of retinol (p= 0.01). The prevalence of VAD, according to the serum concentrations of retinol, was 14%, and of this percentage 23.3% had NB according to the standardized interview, and 22.0% according to electroretinography. NB diagnosed by both methods showed an association with VAD according to the serum concentrations of retinol. Of these individuals with NB, according to the standardized interview, 6.9% showed severe VAD, 10.3% moderate VAD and 82.8% marginal VAD. Conclusion: The standardized interview for the diagnosis of NB can be a good strategy to evaluate the nutritional status of vitamin A, and it is a simple, non-invasive and low-cost method.

INTRODUCCIÓN: Objetivo: Comparar el diagnóstico de NB mediante el uso de la entrevista estandarizada de la Organización Mundial de la Salud/Organización Panamericana de la Salud (OMS/OPS) con electrorretinografía, y también evaluar la asociación de estos diagnósticos con las concentraciones séricas de retinol en la clase III personas obesas. Métodos: se estudiaron pacientes adultos de ambos sexos, en el grupo de 20 a 60 años de edad, con un IMC ≥ 40 kg/m². La NB se diagnosticó mediante electrorretinografía y la entrevista estandarizada validada por la OMS/OPS. El nivel sérico de retinol se cuantificó mediante el método HPLC-UV, y el DVA se diagnosticó cuando los niveles eran <1.05 µmol / L, y también se evaluó la gravedad. El análisis estadístico se realizó a través del Paquete Estadístico para las Ciencias Sociales, versión 21.0 (p <0.05). Resultados: IMC promedio fue de 44.9 ± 11.8 kg / m², y se encontró una correlación negativa en los niveles séricos de retinol (p = 0.01). La prevalencia de DVA, según las concentraciones séricas de retinol, fue del 14%, y de este porcentaje, el 23,3% tenía NB de acuerdo con la entrevista estandarizada y el 22,0% según la electrorretinografía. La NB diagnosticada por ambos métodos mostró una asociación con VAD según las concentraciones séricas de retinol. De estos individuos con NB, según la entrevista estandarizada, el 6,9% mostró VAD grave, el 10,3% de VAD moderado y el 82,8% de VAD marginal. Conclusión: la entrevista estandarizada para el diagnóstico de NB puede ser una buena estrategia para evaluar el estado nutricional de la vitamina A, y es un método simple, no invasivo y de bajo costo.

Longitudinal assessment of retinal structure and function reveals a rod-cone degeneration in a guinea pig model initially presented as night blind.

We have previously reported a naturally occurring retinopathy in a population of guinea pigs, where the affected animals presented a defect of the rod-mediated vision. The purpose of this study was to investigate if the mutants were affected with a stationary or degenerative retinopathy and to identify the cellular origin of this unique disorder. Electroretinogram (ERG) [postnatal day 1 (P1) to P450], light (LM) and electron microscopy (EM) [P5, P150, P450], and immunohistochemistry [P30, P150, P450] were evaluated from normal and mutant animals. Irrespective of age, the scotopic ERGs of mutants could only be evoked by bright flashes, and the resulting ERGs were of photopic waveform. Interestingly, the amplitude of the cone and the rod/cone a-waves was always of smaller amplitude in mutants, but this difference tended to decrease with age. In contrast, the b-waves were of larger amplitude than normal in photopic ERGs obtained prior to age 25 (days) and prior to age 10 for rod/cone ERGs. LM revealed, in mutants, an absence of the outer segment layer (OSL) with a reduction in the outer nuclear layer (ONL) thickness. EM disclosed the presence of cone outer segment (OS) while no rod OS could be evidenced. Immunohistochemistry revealed the presence of rhodopsin, both cone opsins as well as normal synaptophysin immunoreactivity. Finally, neither the retinal structure nor the function in the mutants achieved normal development. Results suggest that mutant animals are suffering from a degenerative retinal disorder that affects the structure and function of rods and cones.

Electroretinographic assessment and diagnostic reappraisal of children with visual dysfunction: a prospective study.

PURPOSE: To assess the presence or absence of a retinal cause of visual impairment using electroretinography (ERG) in children with no obvious discernable cause on ocular examination. DESIGN: Prospective observational case series. MATERIALS AND METHODS: A prospective study was carried out involving 120 children with the mean age 4.4+/-3.2 years with visual dysfunction. All children underwent ERG under general anesthesia using a special handheld mini-Ganzfeld (Kurbisfeld) dome. RESULTS: Fifty-two (43.3%) children were male and 68 (56.7%) were female. The clinical diagnosis was as follows: Leber's congenital amaurosis (LCA) (n=47), achromatopsia (n=25), congenital stationary night blindness (CSNB) (n=9) and others (unclassifiable, n=39). The visual acuity ranged from perception of light (PL) to PL with projection in children with LCA. In the rest (n=73), some sort of visually guided behavior was discernable. Following ERG, a diagnostic reappraisal resulted as follows: LCA (n=49), achromatopsia (n=28), CSNB (n=4), cone-rod dystrophy (n=22), rod-cone degeneration (n=7), normal (n=8) and others (unclassifiable, n=2). Except for the two unclassifiable cases, ERG was successful in the diagnosis or exclusion of retinal dysfunction in the rest. By Pearson Chi-square test, there was a statistically significant association between the clinical and ERG diagnosis (P < 0.001). CONCLUSION: LCA was the commonest cause of visual dysfunction in our series. A statistically significant correlation between clinical and electrophysiological diagnosis was seen. ERG helped in firmly establishing the presence or absence of global retinal dysfunction in the majority (118/120) of pediatric patients with visual dysfunction.

[Traffic ophthalmology. Assessment of ability to drive in road traffic]. / Verkehrsophthalmologie. Fahreignungsbegutachtung im Strassenverkehr.

Assessment of an individual's ability to drive in road traffic is an important part of the ophthalmologist's work. It fulfils the ophthalmologist's duty to care for the patient and increases general road traffic safety. This assessment requires testing of visual acuity, visual field, mesopic vision and glare, motility, binocular vision and colour vision. Also the optical media and the fundus have to be examined. If an optical aid is necessary, it should be suitable for use in road traffic. In some cases restrictions are necessary, which should be noted in the driver's licence. Testing of visual function has to be performed with standardised procedures according to the recommendations of DOG and BVA. This article will provide readers with an overview of current practices in assessing the ability to drive in road traffic and enable them to render an accurate professional opinion regarding driver's licences.

A new, simple, inexpensive means of testing functional vitamin A status: the night vision threshold test (NVTT). A preliminary field-test report.

Vitamin A deficiency is the leading cause of preventable childhood blindness in developing countries. Each year, an estimated 13.5 million children world-wide are unable to adapt to the dark and half a million children progress to complete blindness annually from lack of vitamin A. Most of the currently available methods for assessing vitamin A status are expensive, require sophisticated instrumentation and are not efficacious in field conditions. A simple, inexpensive method was developed to identify children with defective dark-adaptability, thereby providing a reflection of marginal vitamin A stores. The purpose of this preliminary study was to test the field-efficacy of the Night Vision Threshold Tester (NVTT). Thirty-nine middle-school children with a mean age of 13.5 +/- 1.37 years were initially tested for their ability to adapt to the dark using the