The significance of changes in pupil size during straylight measurement and with varying environmental illuminance / Importancia de los cambios del tamaño de la pupila durante la medición de la dispersión lumínica, con variación de iluminancia ambiental

Purpose: In this work, we investigated the pupillary conditions during straylight measurement, and the potential effect this might have on the measured straylight. Methods: Five young (26-29-years-old) and 15 older (50-68-years-old) individuals participated in this study. First, the pupil diameter of both eyes was measured at three room illuminances. Next, straylight was assessed at two room illuminances. Simultaneously, the change in pupil size of the fellow eye was registered by a camera. Results: Pupil size decreased with room illuminance and with age (both p < 0.05). The dependency of pupil size on age decreased as room illuminance increased (0.018 mm/year at 4 lux, 0.014 mm/year at 40 lux, and 0.008 mm/year at 400 lux illuminances). However, during straylight measurement, pupil sizes hardly differed between 4 and 40 lux illuminances. Respective pupil sizes corresponded with 399 and 451 lux adaptation on average. No statistically significant difference was found between the straylight under the two illuminances with average R2 = 0.85, p < 0.05. Conclusion: We conclude that the illuminance of the examination room during straylight assessment does not affect the outcome in normal eyes. In fact, under mesopic and scotopic conditions, the luminance of the test field is so much higher than that of the room so that it determines the pupil size. Regardless of the lighting level, straylight measured in a laboratory, is valid for photopic pupils at an adaptation level corresponding with about 400 lux room illuminance

Objetivo: En este trabajo investigamos las condiciones de la pupila durante la medición de la dispersión lumínica, así como el efecto potencial que ello podría tener sobre la dispersión lumínica medida. Métodos: En el estudio participaron cinco individuos jóvenes (de 26 a 29 años) y 15 mayores (de 50 a 68 años). En primer lugar, se midió el diámetro de la pupila de ambos ojos con tres iluminancias ambientales. A continuación, se evaluó la dispersión lumínica con dos iluminancias ambientales. De manera simultánea, se registró mediante una cámara el cambio del tamaño de la pupila del otro ojo. Resultados: El tamaño de la pupila se redujo con la iluminancia ambiental y la edad (p < 0,05 para ambos). La dependencia del tamaño de la pupila con la edad se redujo a medida que aumentaba la iluminancia ambiental (0,018 mm/año a iluminancias de 4 lux, 0,014 mm/año a 40 lux, y 0,008 mm/año a 400 lux). Sin embargo, durante la medición de la dispersión lumínica, los tamaños de la pupila difirieron escasamente entre iluminancias de 4 y 40 lux. Los tamaños de la pupila respectivos se correspondieron con una adaptación de 399 y 451 lux, de media. No se encontraron diferencias estadísticamente significativas entre la dispersión lumínica bajo las dos iluminancias y la media de R2 = 0,85, p < 0,05. Conclusión: Concluimos que la iluminancia de la sala de examen durante la valoración de la dispersión lumínica no afecta al resultado en ojos normales. De hecho, en condiciones mesópicas y fotópicas, la iluminancia del campo de prueba es muy superior a la de la sala, lo cual determina el tamaño de la pupila. Independientemente del nivel de iluminación, la dispersión lumínica medida en un laboratorio es válida para pupilas fotópicas a un nivel de adaptación correspondiente a una iluminancia ambiental de alrededor de 400 lux

The significance of changes in pupil size during straylight measurement and with varying environmental illuminance.

PURPOSE: In this work, we investigated the pupillary conditions during straylight measurement, and the potential effect this might have on the measured straylight. METHODS: Five young (26-29-years-old) and 15 older (50-68-years-old) individuals participated in this study. First, the pupil diameter of both eyes was measured at three room illuminances. Next, straylight was assessed at two room illuminances. Simultaneously, the change in pupil size of the fellow eye was registered by a camera. RESULTS: Pupil size decreased with room illuminance and with age (both p<0.05). The dependency of pupil size on age decreased as room illuminance increased (0.018mm/year at 4 lux, 0.014mm/year at 40 lux, and 0.008mm/year at 400 lux illuminances). However, during straylight measurement, pupil sizes hardly differed between 4 and 40 lux illuminances. Respective pupil sizes corresponded with 399 and 451 lux adaptation on average. No statistically significant difference was found between the straylight under the two illuminances with average R2=0.85, p<0.05. CONCLUSION: We conclude that the illuminance of the examination room during straylight assessment does not affect the outcome in normal eyes. In fact, under mesopic and scotopic conditions, the luminance of the test field is so much higher than that of the room so that it determines the pupil size. Regardless of the lighting level, straylight measured in a laboratory, is valid for photopic pupils at an adaptation level corresponding with about 400 lux room illuminance.

Changes in Intraocular Straylight and Visual Acuity with Age in Cataracts of Different Morphologies.

PURPOSE: To investigate the significance of difference in straylight of cataract eyes with different morphologies, as a function of age and visual acuity. METHODS: A literature review to collect relevant papers on straylight, age, and visual acuity of three common cataract morphologies leads to including five eligible papers for the analysis. The effect of morphology was incorporated to categorize straylight dependency on the two variables. We also determined the amount of progression in a cataract group using a control group. RESULTS: The mean straylight was 1.22 log units ± 0.20 (SD) in nuclear (592 eyes), 1.26 log units ± 0.23 in cortical (776 eyes), and 1.48 log units ± 0.34 in posterior subcapsular (75 eyes) groups. The slope of straylight-age relationship was 0.009 (R2 = 0.20) in nuclear, 0.012 (R2 = 0.22) in cortical, and 0.014 (R2 = 0.11) in posterior subcapsular groups. The slope of straylight-visual acuity relationship was 0.62 (R2 = 0.25) in nuclear, 0.33 (R2 = 0.13) in cortical, and 1.03 (R2 = 0.34) in posterior subcapsular groups. CONCLUSION: Considering morphology of cataract provides a better insight in assessing visual functions of cataract eyes, in posterior subcapsular cataract, particularly, in spite of notable elevated straylight, visual acuity might not manifest severe loss.