Objectives: To determine the difference in light reflection of oral mucosa covering titanium (Ti) or zirconia (ZrO2) abutments as it relates to the thickness of the covering mucosa. Material and methods: Fifteen anterior implants (Astra Osseo speed®) in 11 patients were fitted with a Ti or a ZrO2 abutment (cross‐over, within‐subject comparison). Hyper‐spectral images were taken with a camera fitted on a surgical microscope. High‐resolution images with 70 nm interval between 440 and 720 nm were obtained within 30 s (1392 × 1024 pixels). Black‐ and white‐point reference was used for spatial and spectral normalization as well as correction for motion during exposure. Reflection spectra were extracted from the image on a line mid‐buccal of the implant, starting 1 mm above the soft tissue continuing up to 3 mm apically. Results: Median soft tissue height is 2.3 mm (min: 1.2 mm and max: 3.1 mm). The buccal mucosa rapidly increases in the thickness, when moving apically. At 2.2 mm, thickness is 3 mm. No perceivable difference between the Ti and ZrO2 abutment can be observed when the thickness of the mucosa is 2±0.1 mm (95% confidence interval) or more. Conclusion: It is expected that the difference in light reflection of soft tissue covering Ti or ZrO2 abutments is no longer noticeable for the human eye when the mucosa thickness exceeds 2 mm. Haemoglobin peaks in the reflection spectrum can be observed and make hyper‐spectral imaging a practical and useful tool for measuring soft tissue health. To cite this article: 
van Brakel R, Noordmans HJ, Frenken J, de Roode R, de Wit GC, Cune MS. The effect of zirconia and titanium implant abutments on light reflection of the supporting soft tissues.
Clin. Oral Impl. Res. 22, 2011; 1172–1178
doi: 10.1111/j.1600‐0501.2010.02082.x

No abstract

The BPM 2 filter is a good early-cataract-simulating filter. Stacking such filters is a good way to increase the cataract density. A drawback is that the BPM 2 filter has a transmission of 66% so stacking filters reduces the overall transmission significantly.

PURPOSE:To compare different methods for the assessment of disability glare sensitivity in the elderly, to arrive at an objective assessment of the condition of the eye. To delineate the importance of straylight values in vision. METHODS: Three groups of subjects were studied: 1) Young subjects without any eye disease, 2) elderly subjects without any eye disease and 3) elderly subjects with (early) cataract in at least one eye. All subjects underwent 2 glare tests, 2 straylight tests, ETDRS visual acuity test, Pelli Robson contrast sensitivity test, refraction, LOCS III cataract classification. Straylight was quantified by means of the straylight parameter s. RESULTS: Repeatability, discriminative ability, and added value as compared to visual acuity were low for the glare tests and good for the straylight measurements. For young normal subjects, with log(s)=0.9, the standard glare situation with low beams gives a contrast reduction of 1.3, whereas for the healthy 77 year olds this increases to 2. With cataract hardly affecting visual acuity, log(s) can be as high as 1.8, resulting in a contrast reduction of 3.4. CONCLUSION: Straylight measurement is of relevance for the assessment of the glare-related hindrance during driving, and can be used to objectify complaints and aid in the decision-making regarding cataract surgery. (J Optom 2009;2:112-118 ©2009 Spanish Council of Optometry) KEY WORDS: straylight; glare sensitivity; disability glare; CIE; aging; driving. RESUMEN OBJETIVO:Comparar diferentes métodos para medir la sensibilidad al deslumbramiento perturbador en sujetos de edades avanzadas, con el fin además de lograr una valoración objetiva de las afecciones oculares. Definir la importancia que tiene la luz dispersa (parásita) sobre la visión. MÉTODOS: Se estudiaron tres grupos de sujetos: 1) Sujetos jóvenes sin ningún tipo de afección ocular, 2) sujetos de edad avanzada sin ningún tipo de afección ocular y 3) sujetos de edad avanzada con cataratas (incipientes) en, al menos, uno de los ojos. A todos los sujetos se les realizaron, entre otras, 2 pruebas de deslumbramiento y 2 pruebas de luz dispersa, se les midió la agudeza visual mediante optotipos ETDRS (siglas en inglés del Estudio sobre el tratamiento temprano de la retinopatía diabética), la sensibilidad al contraste con el test de Pelli-Robson, la refracción, y se clasificó la catarata (para sujetos del tercer grupo) utilizando el Sistema de Clasificación de Opacidades del Cristalino( o sus siglas en inglés, LOCS III). La luz dispersa (parásita) se cuantificó por medio del parámetro de luz dispersa s. RESULTADOS: La repetibilidad, la capacidad discriminativa, y el valor añadido, resultaron ser bajos para los tests de deslumbramiento pero buenos para las medidas de la luz dispersa (en comparación con los valores que proporciona la medida de la agudeza visual). Para los sujetos jóvenes sin patologías oculares, con log(s)=0,9, la situación habitual de deslumbramiento con haces bajos causa una reducción del contraste del 1,3, mientras que para l...