Light exposure from microscope versus intracameral illumination during cataract surgery

Purpose: To evaluate light exposure from microscope versus intracameral illuminations to patient's and surgeon's retina during cataract surgery. Methods: Thirty consecutive patients who had cataract surgery using microscope and intracameral illuminations. At the point of the ocular of an operating microscope, optical illuminance and irradiance from the microscope illumination (60, 40, 20% intensity) and the intracameral illumination (60% intensity) were measured using a light meter and a spectrometer at a pause after lens capsule polishing in cataract surgery. Results: Average illuminance (lux) was 1.46, 0.66, 0.27, and 0.1 from 60%, 40%, 20% intensity microscope illuminations and 60% intracameral illumination. Average total spectral irradiance (?W/cm2) was 1.25, 0.65, 0.26, and 0.03 from 60%, 40%, 20% intensity microscope illuminations and 60% intracameral illumination. Conclusion: Microscope ocular illuminance and irradiance during cataract surgery were higher in the microscope illumination than in the intracameral illumination. It suggests that light exposure reaching patient's and surgeon's retina during cataract surgery is lower in the intracameral illumination than in the microscope illumination.

Caracterización de la Lámpara Flash-LED: EBNeuro Usada para Adquirir Potenciales Evocados Visuales en Ratas / Characterization of the Flash-LED Lamp: EBNeuro Used to Acquired Visual Evoked Potentials in Rats

Resumen: La señal de la amplitud en análisis de Potenciales Evocados Visuales (PEVs) es una variable que depende del tipo y posición de los electrodos, de la fuente, del estímulo y por consecuente, de la intensidad luminosa por lo que es fundamental reportarla para cada diseño experimental y así, garantizar su reproducibilidad. El objetivo de este trabajo es caracterizar una lámpara con 96 LEDs para la adquisición de PEVs en ratas. Se midió la iluminancia y la intensidad luminosa promedio en un sistema espacial XYZ de 8 cm3 aplicable a un sistema estereotáxico para la fijación de ratas. Se realizaron desplazamientos cada 2 cm en cada plano. Se observó que debido a la distribución geométrica de los LEDs la distribución de la iluminancia no sigue la ley del inverso cuadrado, ya que aumenta conforme la lámpara se aleja. Finalmente, se seleccionó una coordenada para la colocación del ojo de la rata empleando una intensidad luminosa promedio para la adquisición del PEV de 1.043 cd e iluminancia de 128.77 luxes a una distancia ojo-lámpara de 9 cm. Una vez caracterizada la intensidad luminosa y de acuerdo con los PEVs obtenidos, esta lámpara puede utilizarse para estudios PEV en ratas en investigaciones posteriores.

Abstract: Signal amplitude for recordings of Visual Evoked Potentials (VEPs) is a variable dependent on the type and position of the electrodes, the source, the stimulus and consequently the luminous intensity; therefore, it is relevant to report it to assure experimental reproducibility. The objective of this work is to characterize flash lamp with 96 LEDs in order to perform the acquisition of VEPs in rats. We measure the illuminance and mean light intensity on space system XYZ of 8 cm3 corresponding to a stereotaxic frame for rodents. Displacements were performed every 2 cm in each plane. Because of the geometric distribution of the LEDs in the EBNeuro lamp the spatial distribution of illuminance does not follow the law of the inverse square, because the illuminance increases as the lamp goes away. Finally a spatial coordinate was selected for the rat eye positioning were the mean luminous intensity was 1.043 cd and 128.77 luxes of illuminance at an eye-lamp distance of 9 cm. According to the obtained VEPs and spatial characterization this lamp can be used for acquire of recordings PEV in rats for further investigations.

Controle de qualidade de monitores de diagnóstico por imagem e iluminância nos espaços de pós-processamento em serviços de imagiologia / Display quality control based on luminance measurements in post-processing units at imaging diagnosis centers

OBJETIVO: Avaliar a qualidade dos monitores de diagnóstico e tratamento de imagem digital em radiologia convencional (raios X) com base nos níveis de luminância. Fez-se a medição da iluminância dos postos de trabalho onde estavam os monitores. MATERIAIS E MÉTODOS: A medição da luminância foi realizada usando-se um detector Unfors Xi Light em cinco instituições, com 23 monitores primários e 22 secundários, sendo 6 usados em urgência, seguindo o método descrito no relatório TG18 da American Association of Physicists in Medicine (AAPM). O instrumento de medida utilizado foi o Delta Ohm HD 9221 luximeter. RESULTADOS: Para as recomendações da AAPM, tanto monitores primários como secundários cumpriram, no geral, os níveis de tolerância. No caso dos níveis de iluminância, nos locais de trabalho dos monitores primários encontravam-se ligeiramente acima do intervalo recomendado. Quanto às recomendações do The Royal College of Radiologists (RCR), os monitores que respeitaram os níveis recomendados estavam em minoria, embora as diferenças não fossem significativas. CONCLUSÃO: Em geral, os resultados foram satisfatórios, embora os monitores não fossem adequados para atingir as recomendações exigentes do RCR. Os níveis de referência entre os monitores primários e secundários deveriam aproximar-se, de modo a garantir a qualidade de imagem. Os monitores para visualização e diagnóstico de imagens médicas devem ser regularmente avaliados para manter um sistema com a qualidade exigida, dada a função que desempenham.

OBJECTIVE: To evaluate the quality of primary and secondary displays of conventional radiography systems based on luminance measurements. The level of ambient lighting within the rooms was also measured. MATERIALS AND METHODS: Luminance measurements were performed with an Unfors Xi Light Detector in 23 primary and 22 secondary displays (six of them utilized in emergency departments) at five different institutions, and according to the method described on the American Association of Physicists in Medicine (AAPM) TG18 report. The level of ambient lighting was measured with Delta Ohm HD 9221 lux meter. RESULTS: In general, both the primary and secondary the displays were compliant with the AAPM guidelines. As regards ambient lighting, the primary workstation rooms were slightly above the recommended levels. As far as The Royal College of Radiologists (RCR) recommendations are concerned, the number of compliant displays corresponded to a minority, with no significant difference, though. CONCLUSION: Although most of the displays could not meet the strict RCR guidelines, in general, the results were satisfactory. The level of agreement between primary and secondary displays should be as high as possible in order to guarantee the image quality. Considering the key role played by diagnostic imaging systems, medical imaging displays must be regularly evaluated to assure that the quality of the imaging system is maintained.

Pupil Size in the Normal Korean Population According to Age and Illuminance

PURPOSE: To report the change of pupil sizes according to age and illuminance in the normal Korean population. METHODS: Normal Koreans outpatients who never had a history of ophthalmic disease were examined. The patients consisted of 320 eyes of 160 patients, which were classified into 8 age decades (teenage to 80's) with 40 eyes in each age group. The vertical and horizontal pupil size and area under 4 different illuminances (3,500, 1,200, 500, 5 lux) were measured using the Colvard pupillometer(R) (OASIS Medical, Glendora, CA, USA). RESULTS: The pupil size was significantly decreased as the age increased under each illuminance. The pupil area measured after dark adaptation was 47.30 mm2 in the teenage group, 43.32 mm2 in the 20's group, 41.94 mm2 in the 30's group, 40.98 mm2 in the 40's group, 40.61 mm2 in the 50's group, 38.60 mm2 in the 60's group, 37.78 mm2 in the 70's group and 35.45 mm2 in the 80's group. The decrease in pupil area was statistically significant. CONCLUSIONS: In the normal Korean population, a significant decrease in pupil size and area was observed with aging. The present study results provide good basic data for cataract and presbyopia refractive surgery.

Estimation of solar radiation and its effects on tooth enamel electron spin resonance dosimetry / 中华放射医学与防护杂志

Objective To investigate solar radiation and its effects on human tooth enamel electron spin resonance (ESR) dosimetry. Methods 11 tooth enamel samples were prepared by mechanical method. The intensity of solar iUuminanee was measured with a light meter, the measured illuminance was converted to insolation using a coefficient. Summation of solar radiation was evaluated. Enamel samples were exposed to 60 Co γ rays followed by sunlight on sunny days, and ESR spectra were scanned after different exposure. Results The solar radiation to the samples was (580 ± 16) MJ/m2. Solar exposure also caused dosimetrie signal. The perpendicular component of dosimetrie signal increased linearly with the amount of solar radiation, another signal close to background tended to saturation. Conclusions The average effect of the solar radiation on the signal was be used to recognize the effect of solar radiation on the enamel, and estimate external dose accurately.

Effect of Difference of Binocular Retinal Illuminance on Stereopsis

PURPOSE: We examined the effect of induced interocular difference of retinal illuminanace on stereopsis. METHODS: Fifty adults who have normal binocularity were examined with neutral density filters. The mean age was 29.1 years. While the monocular retinal illuminance was gradually reduced by increasing the value of neutral density filters, we measured the best corrected visual acuity and stereoacuity with Titmus test and Lang test. We used neutral density filter from 1.0 neutral density (ND, 10% transmit) to 3.0ND (0.1% transmit) with intervals of 0.2ND. RESULTS: The best corrected visual acuity began to decrease significantly when the value of neutral density filter reached 2.0ND (1% transmit). Stereoacuity also began to decline when the value was 1.4ND(4% transmit) with Titmus test and 1.6ND (2.5% transmit) with Lang test. CONCLUSIONS: Change of retinal illuminance effects more on stereoacuity than visual acuity as stereoacuity decreased earlier by increasing the value of density filters. These results imply that the stereopsis test could be more useful than visual acuity test for detecting ocular abnormalities influencing the retinal illuminance.

Effects of Retinal Illuminance on Visual Acuity and Fusion

PURPOSE: We examined the effects of induced retinal illuminance on visual acuity and fusion. METHODS: Fifty adults with best corrected visual acuity of 20/20 or better and normal binocularity and fusion were examined. To examine the effect of retinal illuminance on visual acuity and the effect of binocular difference of retinal illuminance on fusion, we used neutral density filter from 0.1 ND to 4.0 ND. While neutral density filter values were increased, we measured the least size fusion slide by major amblyoscope as well as the best corrected visual acuity. RESULTS: The best corrected visual acuity and the level of fusion were decreased significantly when monocular retinal illuminance was reduced to 2.0 ND (P<0.01, P<0.01, respectively). Although the visual acuity and fusion were equally influenced by retinal illuminance, the effect on fusion was more prominent when retinal illuminance decreased greatly. CONCLUSIONS: These results will be of help for the prevention and early detection of amblyopia, although further study will be needed in order to fully evaluate the influences of other factors on binocular fusion.