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...

Eye tracking-based gaze recordings are a promising tool to assess oculomotor and visual performance in a communication-free manner. Calculating quantitative parameters from specific gaze responses could assist in the characterization of functional visual performance in children, independent of age. Gaze responses are a useful addition to standard VFA in clinical practice.

Stray light in spectacle lenses may affect the overall vision. It may also affect the measurement of ocular stray light, contrast sensitivity, or glare sensitivity. This article describes common stray light characteristics for glass and plastic spectacle lenses and compares this to the stray light characteristics of the eye, which are well known from the literature. Stray light is described by the skirts of the point-spread function (PSF), which were measured for angles from 4 degrees to 30 degrees. The PSF of spectacle lenses appears to follow the equation PSF = a(10). (theta/10)b, with a(10) and b representing fitting parameters and theta representing the stray light angle. The slope b is on average -2, which similar to that of the eye. For clean spectacle lenses, the PSF is usually at least an order of magnitude lower than that of the eye, whereas "as worn" (uncleaned) spectacle lenses may approach the PSF of the eye. To reach the PSF of the eye, the spectacle lens needs to be contaminated by as much as one or two fingerprints. The article also shows that plastic spectacle lenses degrade much faster than glass spectacle lenses when looking at the amount of stray light.

PURPOSE. To investigate the optimal procedures for multichannel visually evoked potentials (VEPs) to detect misrouting in albinism subjects. METHODS. Investigations were done in a phenotypically heterogeneous group of 180 albinism subjects and 187 controls with and without ocular pathology. We retrospectively compared standard flash VEP (fVEP), high-frequency fVEP with a handheld device (hh fVEP), patternonset VEP (poVEP), and short-onset acuity sweep VEP. The diagnostic power of these stimuli were estimated by calculating the area under the curve (AUC). Subjects were divided in three age groups (<3, 3-6 [toddler], and ‡6 years). Subjects ‡6 years of age were further divided in two visual acuity groups (0.3 logMAR and >0.3 logMAR). RESULTS. The optimal stimulus was hh fVEP, standard fVEP, and poVEP 60 0 for subjects <3, 3-6, and ‡6 years of age, respectively. In subjects ‡6 years old with poor visual acuity, the area under the curve of fVEP was almost equal to that of poVEP 60 0. CONCLUSIONS. For the optimal detection of misrouting with multichannel VEP recordings, we recommend using a high-frequency hh fVEP in children <3 years of age, standard fVEP in toddlers, and poVEP 60 0 in subjects ‡6 years of age. fVEP can also be used in the oldest age group for subjects with visual acuity of >0.3 logMAR. Remarkably, some albinism subjects showed misrouting on full-field stimulation but normal routing of the central retina, suggesting that not the whole line of decussation is shifted temporally.

Purpose To help differentiate CLN3 (Batten) disease, a devastating childhood metabolic disorder, from the similarly presenting early‐onset Stargardt disease (STGD1). Early clinical identification of children with CLN3 disease is essential for adequate referral, counselling and rehabilitation. Methods Medical chart review of 38 children who were referred to a specialized ophthalmological centre because of rapid vision loss. The patients were subsequently diagnosed with either CLN3 disease (18 patients) or early‐onset STGD1 (20 patients). Results Both children who were later diagnosed with CLN3 disease, as children who were later diagnosed with early‐onset STGD1, initially presented with visual acuity (VA) loss due to macular dystrophy at 5–10 years of age. VA in CLN3 disease decreased significantly faster than in STGD1 (p = 0.01). Colour vision was often already severely affected in CLN3 disease while unaffected or only mildly affected in STGD1. Optic disc pallor on fundoscopy and an abnormal nerve fibre layer on optical coherence tomography were common in CLN3 disease compared to generally unaffected in STGD1. In CLN3 disease, dark‐adapted (DA) full‐field electroretinogram (ERG) responses were either absent or electronegative. In early‐onset STGD1, DA ERG responses were generally unaffected. None of the STGD1 patients had an electronegative ERG. Conclusion Already upon presentation at the ophthalmologist, the retina in CLN3 disease is more extensively and more severely affected compared to the retina in early‐onset STGD1. This results in more rapid VA loss, severe colour vision abnormalities and abnormal DA ERG responses as the main differentiating early clinical features of CLN3 disease.