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Non-ionized, High-resolution Measurement of Internal and Marginal Discrepancies of Dental Prosthesis Using Optical Coherence Tomography
摘要： An internal and marginal fit between prosthesis and abutment are important factors of the durability of dental prosthesis. In this study we have proposed the use of swept-source optical coherence tomography (SS-OCT) as a novel application for non-ionized and high-resolution measurements of internal and marginal discrepancies at anatomically critical four points, such as occlusal, angle, axial, and margin during prosthesis attachment. A tooth model was fabricated by 3D printing technique and the dental prosthesis was designed using dental CAD software. The cross-sectional images along with intensity peak profile analysis of the sample were acquired using OCT system for measurements of fit. The demonstrated qualitative and quantitative evaluations can be well-utilized for assessment of the internal and marginal fit of dental prosthesis.
关键词： Intensity analysis,Dental prosthesis,Internal and marginal fit,Swept-source optical coherence tomography
更新于2025-09-23 15:23:52
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The first deaf-blind patient in Russia with Argus II retinal prosthesis system. What he sees and why
摘要： A 59-year-old man with retinitis pigmentosa and hearing loss (clinical Usher syndrome) underwent surgery to implant the Argus II retinal prosthesis system in the right eye. This is the first case of retinal implant surgery in the Russian Federation. In this study we propose a new method for evaluating the functional results after implantation of the Argus II, the statistical analysis was performed to find correlations between the sizes of phosphenes that the patient drew and then were digitalized, and the height of the subimplant interface, retinal thickness, impedance, and perceptual threshold, which showed interesting mixed results. Correlation analysis showed the weak dependency between the size of a phosphene and the perceptual threshold and we did not find significant correlations between a phosphene and the height of the interface, impedance and retinal thickness.
关键词： Argus II,Usher syndrome,retinitis pigmentosa,deaf-blind,blind,artificial vision,retinal prosthesis system,retinal implant,deafblind
更新于2025-09-23 15:23:52
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Improvement in reading performance through training with simulated thalamic visual prostheses
摘要： Simulations of artificial vision are used to provide the researcher an opportunity to explore different aspects of visual prosthesis device design by observing subject performance on various tasks viewed through the simulation. Such studies typically use normal, sighted subjects to measure performance at a given point in time. Relatively few studies examine performance changes longitudinally to quantitatively assess the benefits from a training plan that would be akin to post-implantation rehabilitation. Here, we had six normal, sighted subjects use a standard reading task with daily practice over eight weeks to understand the effects of an intensive training schedule on adaptation to artificial sight. Subjects read 40 MNREAD-style sentences per session, with a new set each session, that were presented at five font sizes (logMAR 1.0–1.4) and through three center-weighted phosphene patterns (2,000, 1,000, 500 phosphenes). We found that subjects improved their reading accuracy across sessions, and that the training lead to an increase of reading speed that was equivalent to a doubling of available phosphenes. Most importantly, the hardest condition, while initially illegible, supported functional reading after training. Consistent with experience-driven neuroplastic changes, gaps in the training schedule lead to transient decreases in reading speed, but, surprisingly, not reading accuracy. Our findings contribute to our larger project of developing a thalamic visual prosthesis and to post-implant rehabilitation strategies.
关键词： training,simulation,rehabilitation,artificial vision,reading performance,visual prosthesis,phosphene patterns
更新于2025-09-23 15:23:52
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In vitro reliability testing and in vivo lifespan estimation of wireless Pixium Vision PRIMA photovoltaic subretinal prostheses suggest prolonged durability and functionality in clinical practice
摘要： Objective. Retinal implants have the potential to restore some sight in patients with retinal degeneration. The PRIMA implant’s novel design features simpler insertion and no transscleral cabling or extraocular components. This in vitro study investigated PRIMA’s durability under real time and accelerated conditions and estimated the device’s lifespan in vivo. Approach. Two potential failure modes were examined: corrosion and overstimulation. Real-time aging was tested using implants immersed in balanced saline solution (BSS) at 37°C, mimicking the intraocular environment. Accelerated aging was examined at 77°C (Arrhenius theory). Confirmatory testing of acceleration factor was performed using different temperatures (37°C-87°C) and weakened implant coatings. The effect of repeated maximum stimulation was tested using a pulsed infrared laser (6x acceleration factor). Data were used to estimate device lifespan. Main results. 175 implants were tested for up to 33 months. No corrosion or water ingress was observed after approximately 20 accelerated years. A pixel failure rate of 0.15% was recorded after 10 accelerated years’ stimulation. The derived lifespan estimation for the PRIMA implant was 27.0 years with a reliability of 90% (95% confidence interval). Significance. The PRIMA implant was found to be robust, with in vitro reliability of at least ten years. The PRIMA implant shows durability and functionality for clinically relevant timespans under similar environmental conditions to the human eye. These results require in vivo confirmation.
关键词： implant corrosion,reliability,retinal prosthesis,lifespan,subretinal
更新于2025-09-23 15:21:01
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Artificial pupil versus contralateral balanced contact lens fit for presbyopia correction
摘要： Purpose: To assess and compare the effects of contact lens-based artificial pupil design and contralateral balanced multifocal contact lens combination (CBMCLC) on visual performance. Methods: This randomized crossover study conducted at the University of Valencia, Spain included 38 presbyopic patients using an artificial pupil contact lens in the nondominant eye and a CBMCLC. After a month of lens wear, the binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance, and near contrast sensitivity and near stereoacuity (NSA) were measured under photopic conditions (85 cd/m2). Moreover, BDVA and binocular distance contrast sensitivity were examined under mesopic conditions (5 cd/m2). Results: Visual acuity at an intermediate distance and near vision was better with the CBMCLC than with the artificial pupil (p<0.05). Statistically significant differences were found in contrast sensitivity between the two types of correction for distance (under mesopic conditions) and for near vision, with the CBMCLC exhibiting better results in both cases (p<0.05). The mean NSA values obtained for the artificial pupil contact lens were significantly worse than those for the CBMCLC (p=0.001). Conclusion: The CBMCLC provided greater visual performance in terms of intermediate and near vision compared with the artificial pupil contact lens.
关键词： Prosthesis fitting,Pupil,Presbyopia/rehabilitation,Dominance, ocular,Contact lenses
更新于2025-09-23 15:21:01
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Translation of a photovoltaic retinal prosthesis
摘要： A silicon-based photovoltaic subretinal prosthesis triggers behavioural responses to pulsed near-infrared light in awake macaques.
关键词： silicon-based,photovoltaic retinal prosthesis,macaques,near-infrared light
更新于2025-09-19 17:13:59
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A review on the current status of retinal prostheses (bionic eye); Pregled informacija o trenutnom stanju retinalnih proteza (bioni?ko oko);
摘要： Argus? II, the first retinal prosthesis is approved for the treatment of patients with retinal pigmentosis. 2011 has received the CE (European Committee) designation and 2013 FDA (Food and Drug Administration) Approval. Retinal prosthesis provides a stable, safe and long-lasting retinal stimulation. The improvement of vision with retinal prosthesis depends on the improvement of the visual resolution, development of the correct neural form for imaging and improvement of the biological compatibility of the device to ensure durability. Once the theme of folklore and science fiction, the idea of returning sight to blind people today is approaching reality.
关键词： retinitis pigmentosa,visual prosthesis,retinal prosthesis
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE 1st Global Conference on Life Sciences and Technologies (LifeTech) - Osaka, Japan (2019.3.12-2019.3.14)] 2019 IEEE 1st Global Conference on Life Sciences and Technologies (LifeTech) - Infrared Laser Stimulation of Cochlear Nerve through a Tympanic Membrane
摘要： Infrared lasers are a novel method for providing neural stimulation. The laser causes an instantiable temperature rise because of optical absorption by water, and opens the heat-sensitive ion channel. Unlike electric stimulation, an infrared laser stimulates nerves without contacting the tissue. Our goal was to develop a novel auditory prosthesis by applying infrared laser stimulation in a hearing aid. This study investigated whether an infrared laser projected through the tympanic membrane could stimulate the cochlear nerves in the ear canal. Mongolian gerbils (Meriones unguiculatus) were studied. A pulsed infrared laser (0.5–12.8 mJ/cm2) and a clicking sound (10–90 dB pe. SPL) were presented to the subjects. The cochlear microphonics (CMs) and compound action potentials (CAPs) were recorded when the clicking sound was presented, while trans-tympanic membrane laser stimulation induced only CAPs. In subsequent experiments, continuous pulsed laser irradiation for 60 minutes did not cause any observable damage on cochlear response and a tympanic membrane. Therefore, trans-tympanic membrane laser stimulation bypasses the need for hair cell depolarization and creates cochlear nerves responses directly, suggesting that a novel hearing aid using an infrared laser could compensate for sensorial hearing loss.
关键词： Auditory prosthesis,infrared laser,noninvasiveness,cochlear implant
更新于2025-09-16 10:30:52
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Handbook of Bioelectronics (Directly Interfacing Electronics and Biological Systems) || Photovoltaic retinal prosthesis for restoring sight to the blind
摘要： Age-related macular degeneration (AMD) is one of the leading causes of blindness in the developed world, with an incidence of 1:500 in patients aged 55–64, and 1:8 in patients over 85 [1]. Retinitis pigmentosa (RP) is an inherited disease blinding about 1 in every 4000 individuals much earlier in life [2]. In both of these conditions the photoreceptor layer degenerates, while the inner retinal neurons survive to a large extent [3–5]. Electrically activating these neurons provides an alternative route for visual information and raises hope for the restoration of sight to the blind.
关键词： age-related macular degeneration,restoring sight,Photovoltaic retinal prosthesis,blindness,retinitis pigmentosa
更新于2025-09-12 10:27:22
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Risks of Intracochlear Pressures From Laser Stapedotomy
摘要： Hypothesis: Surgical manipulations during laser stapedotomy can produce intracochlear pressure changes comparable to pressures created by high-intensity acoustic stimuli. Background: New-onset sensorineural hearing loss is a known risk of stapes surgery and may result from pressure changes from laser use or other surgical manipulations. Here, we test the hypothesis that high sound pressure levels are generated in the cochlea during laser stapedotomy. Methods: Human cadaveric heads underwent mastoidectomy. Fiber-optic sensors were placed in scala tympani and vestibuli to measure intracochlear pressures during key steps in stapedotomy surgery, including cutting stapedius tendon, lasering of stapedial crurae, crural downfracture, and lasering of the footplate. Results: Key steps in laser stapedotomy produced high-intensity pressures in the cochlea. Pressure transients were comparable to intracochlear pressures measured in response to high intensity impulsive acoustic stimuli. Conclusion: Our results demonstrate that surgical manipulations during laser stapedotomy can create significant pressure changes within the cochlea, suggesting laser application should be minimized and alternatives to mechanical downfracture should be investigated. Results from this investigation suggest that intracochlear pressure transients from stapedotomy may be of sufficient magnitude to cause damage to the sensory epithelium and affirm the importance of limiting surgical traumatic exposures.
关键词： Stapedectomy,Noise induced hearing loss,Stapedotomy,Intracochlear pressure,Stapes prosthesis
更新于2025-09-12 10:27:22