Previous work on visual short-term memory (VSTM) has encompassed various stimulus attributes including spatial frequency, color, and contrast, revealing specific time courses and a dependence on stimulus parameters. This study investigates visual short-term memory for binocular depth, using dynamic random dot stereograms (DRDS) featuring disparity planes in front of or behind the plane of fixation. In a delayed match-to-sample paradigm, we employed four distinct reference disparities (17.5’, 28.8’ either crossed or uncrossed) at two contrast levels (20%, 80%), spanning interstimulus intervals (ISI) of up to 4 s. Test stimuli represented a range of equally spaced values centered around the reference disparity of the ongoing trial. In addition, the impact of a memory masking stimulus was also tested in a separate experiment. Accuracy and point of subjective equality (PSE) served as performance markers. The performance, indicated by the accuracy of responses, was better for smaller reference disparities (±17.5’) compared to larger ones (±28’), but both deteriorated as a function of ISI. The PSE demonstrated a consistent shift with increasing ISIs, irrespective of the magnitude of the initial disparity, converging gradually toward the range of 20–22’ and deviating from the reference disparity. Notably, the influence of masking stimuli on the PSE was more marked when the mask disparity diverged from the reference value. The findings from our study indicate that the retention of absolute disparity in memory is imprecise, it deteriorates with retention time or due to perturbation by dissimilar masking stimuli. As a result, the memory trace is gradually replaced by a default depth value. This value could potentially signify an optimal point within low-level perceptual memory, however, our results are better explained by perceptual averaging whereby the visual system computationally derives a statistical summary of the presented disparities over time. The latter mechanism would aid in the computation of relative disparity in a dynamically changing environment.

Bioactive glass materials have been used for decades in orthopedic surgery, traumatology, and oral and maxillofacial surgery to repair bone defects. This study aimed to evaluate in vitro the survival and proliferation of MG63 human osteosarcoma-derived cells on S53P4 bioactive glass (BonAlive^® granules). Microscopic visualization was performed to directly observe the interactions between the cells and the material. Osteoblast-like cells were examined on non-adherent test plates, on tissue culture (TC)-treated plates and on the surface of the bioglass to assess the differences. Cell survival and proliferation were monitored using a CCK-8 optical density assay. Comparing the mean OD of MG63 cells in MEM on TC-treated plates with cells on BG, we detected a significant difference (p < 0.05), over each time of observation. The sustained cell proliferation confirmed the non-cytotoxic property of the bioglass, as the cell number increased continuously at 48, 72, 96, and 168 h and even did not plateau after 168 h. Since the properties of bioglasses can vary significantly depending on their composition and environment, a thorough characterization of their biocompatibility is crucial to ensure their effective and appropriate application—for example, during hip and knee prosthesis insertion.

The chapter discusses the integration of additive manufacturing (AM) technologies in fabricating personalized implantable prosthetics. It highlights the evolution and expansion of three-dimensional (3D) printing in medical applications, such as orthopedics, neurosurgery, dentistry, and reconstructive surgery. Various AM techniques, such as laser powder bed fusion, electron beam melting, and stereolithography, have facilitated the production of complex structures tailored to individual patient needs. Key advancements include the development of biocompatible materials like titanium and polyether ether ketone (PEEK), as well as surface modifications that enhance osseointegration. Additionally, emerging technologies such as 4D printing and smart sensors are explored for their potential in further optimizing prosthetic functionality and real-time monitoring of implants. Despite these innovations, challenges remain in terms of regulatory approval, cost reduction, and ensuring long-term clinical safety. The document stresses the importance of multidisciplinary collaboration among medical professionals, engineers, and biotechnologists to advance the field of implantable prosthetics. <!----> <!----> <!----> <!---->

Background and Objectives: Visual impairment and reduced stereovision significantly impact the quality of life and increase fall risk in older adults. While standard clinical assessment of visual functions is essential in this population, its use is often limited by the need for specialized equipment and trained personnel. Tablet-based screening tools offer a practical alternative but require clinical validation. This study aimed to assess the agreement, reliability, and diagnostic performance of a tablet-based screening application (index methods) compared to established clinical reference methods for assessing visual acuity (VA) and stereovision (SV) in adults over 60 years. Materials and Methods: This prospective, non-blinded, cross-sectional, feasibility study included two cohorts: a test–retest group of 24 older adults assessed twice within 7 days, and a clinical cross-sectional group of 135 participants recruited from primary care practices. VA was measured using tablet-based Landolt C test and compared with an ETDRS-style chart, while stereovision was assessed using tablet-based static and dynamic random dot stereograms and compared with the TNO stereotest. Agreement and reliability were evaluated using Bland–Altman analysis, intraclass correlation coefficients (ICC), and receiver operating characteristic (ROC) curves. Results: The index VA method demonstrated good test–retest reliability (ICC = 0.79) with no significant difference between repeated measurements. In the clinical cross-sectional group, visual acuity measurements showed a small mean bias (0.022 logMAR) between the index and reference methods, which remained within clinically acceptable limits, particularly in the intermediate acuity range. For stereovision, the index SV tests showed high test–retest agreement. Using a TNO cutoff of 480 arcsec, the index SV method demonstrated good diagnostic accuracy (AUC 0.87 for static and 0.85 for dynamic stimuli) with high sensitivity for detecting impaired stereovision. Conclusions: The tablet-based index method provided reliable and clinically comparable results for VA and SV assessments in older adults, supporting its potential use as a screening tool in primary care and community-based settings.

Purpose: This study aimed to optimize dynamic random dot correlogram (DRDC) and stereogram (DRDS) stimuli to evoke steady-state visual evoked potentials (ssVEP) on multiple EEG channels for the objective assessment of stereopsis. Methods: EEG recordings were conducted on 22 healthy adults (mean age: 30.2 ± 5.8 years) while viewing cyclopean and control stimuli. DRDC and DRDS were presented at three temporal frequencies (0.9375, 1.875, and 3.75 cycles per second, cps) using anaglyphic channel separation. The ssVEP responses were analyzed using T ² _circ statistical test to determine the most effective stimulus for eliciting significant cortical activity. Results: DRDC at 1.875 cps evoked significant ssVEP responses in 93% of participants on at least one occipital electrode (O1, Oz, O2) and in 100% when including parietal-occipital electrodes. DRDS at similar frequencies also produced robust responses but required additional parietal electrode monitoring. Monocular control measurements confirmed that responses were stereo-specific. Conclusions: DRDC at 1.875 cps was the most effective stimulus for objective electrophysiological assessment of stereopsis, demonstrating high reliability with minimal electrode setups. These findings support the integration of optimized ssVEP protocols into clinical assessments, particularly for non-verbal or pediatric populations.