Modular Lens Research Articles

Evaluation of safety after optic exchange of a modular intraocular lens.

To characterize safety of optic exchange using a modular lens. 3 study sites, New Zealand, Philippines. Prospective clinical study. Harmoni Modular intraocular lens (HMIOL) with separate base and optic components was implanted in the study eye (monovision target -1.50 diopter). Contralateral eyes received standard monofocal IOLs. Subjects could elect optic exchange 3 months after primary implantation. Adverse events (AEs) and endothelial cell loss (ECL) were assessed through 12 months of follow-up. 114 subjects successfully received HMIOL and 114 received control lens in contralateral eye. At 3 months, 65 HMIOL eyes had optic exchange because of unsatisfactory visual outcome from high monovision (exchange cohort); 49 eyes received no exchange (no exchange cohort). Exchange, no exchange, and control cohorts reported ocular AEs in 10 (15%), 6 (12%), and 14 (12%) eyes, respectively. No posterior capsular rupture occurred during optic exchange procedures. Short-term (12-month) posterior capsule opacification (PCO) evaluation showed that all eyes had PCO grade 1 or less at 12 months; no Nd:YAG capsulotomy was performed in the exchange cohort. No exchange and exchange cohorts had similar ECL at 3 months vs preoperative baseline (-4.5%, n = 48 and -4.0%, n = 65). In the exchange cohort, additional 2.7% ECL occurred 3 months after optic exchange compared with preexchange baseline; ECL was significantly below the 14% threshold (P < .001) and was 5.8% at 12 months. HMIOL safety outcomes were comparable with standard monofocal IOLs; HMIOL may provide an effective method for correcting postoperative refractive errors.

A Fast Calibration Method for Photonic Mixer Device Solid-State Array Lidars.

The photonic mixer device (PMD) solid-state array lidar, as a three-dimensional imaging technology, has attracted research attention in recent years because of its low cost, high frame rate, and high reliability. To address the disadvantages of traditional PMD solid-state array lidar calibration methods, including low calibration efficiency and accuracy, and serious human error factors, this paper first proposes a calibration method for an array complementary metal–oxide–semiconductor photodetector using a black-box calibration device and an electrical analog delay method; it then proposes a modular lens distortion correction method based on checkerboard calibration and pixel point adaptive interpolation optimization. Specifically, the ranging error source is analyzed based on the PMD solid-state array lidar imaging mechanism; the black-box calibration device is specifically designed for the calibration requirements of anti-ambient light and an echo reflection route; a dynamic distance simulation system integrating the laser emission unit, laser receiving unit, and delay control unit is designed to calibrate the photodetector echo demodulation; the checkerboard calibration method is used to correct external lens distortion in grayscale mode; and the pixel adaptive interpolation strategy is used to reduce distortion of distance images. Through analysis of the calibration process and results, the proposed method effectively reduces the calibration scene requirements and human factors, meets the needs of different users of the lens, and improves both calibration efficiency and measurement accuracy.

The effects of predictor method factors on selection outcomes: A modular approach to personnel selection procedures.

Past reviews and meta-analyses typically conceptualized and examined selection procedures as holistic entities. We draw on the product design literature to propose a modular approach as a complementary perspective to conceptualizing selection procedures. A modular approach means that a product is broken down into its key underlying components. Therefore, we start by presenting a modular framework that identifies the important measurement components of selection procedures. Next, we adopt this modular lens for reviewing the available evidence regarding each of these components in terms of affecting validity, subgroup differences, and applicant perceptions, as well as for identifying new research directions. As a complement to the historical focus on holistic selection procedures, we posit that the theoretical contributions of a modular approach include improved insight into the isolated workings of the different components underlying selection procedures and greater theoretical connectivity among different selection procedures and their literatures. We also outline how organizations can put a modular approach into operation to increase the variety in selection procedures and to enhance the flexibility in designing them. Overall, we believe that a modular perspective on selection procedures will provide the impetus for programmatic and theory-driven research on the different measurement components of selection procedures. (PsycINFO Database Record

Evaluation of stability and capsular bag opacification of a new foldable adjustable intraocular lens.

Incorrect lens power remains one of the most common reasons for intraocular lens explantation/exchange. We evaluated stability and effect on capsular bag opacification of a new foldable modular lens system, with a base component and an optic component in rabbit eyes. Bilateral phacoemulsification was performed on six rabbits; one eye received the test lens (Harmoni Modular Lens, ClarVista Medical), whereas the other received a single-piece hydrophobic acrylic control lens (SA60AT, Alcon). Slit-lamp examinations were performed at postoperative weeks 1, 2, 3, 4 and 6. All rabbits were sacrificed at week 6. After enucleation, the eyes were examined grossly from the Miyake-Apple view. Following, all globes were sectioned and processed for histopathological examination. The modular lens was stable in all six rabbits. Uveal biocompatibility was similar to or better in the test eyes when compared with control eyes up to 6 weeks postoperatively. Overall, capsular bag opacification was found to be significantly lower in the test eyes when compared with control eyes. At the 6-week gross examination, central posterior capsule opacification was scored as 0.58 ± 0.73 in the test group, and as 3.00 ± 1.26 in the control group (paired two samples for means t-test; two-tail P = 0.005). The Harmoni Modular system remains stable within the capsular bag after implantation. Due to the design of the base component featuring long loops, along with peripheral anterior and posterior square edges, the lens appeared to prevent overall capsular bag opacification in the rabbit model.

Focus on nanoscience and nanotechnology

Focus on nanoscience and nanotechnology

A Transcutaneous Bone Digitizer for Minimally Invasive Registration in Orthopedics: A Real-Time Focused Ultrasound Beam Approach

Computer-guided navigation of surgical tool position in computer-assisted orthopedic systems requires the registration of computer tomographic (CT) images with underlying bone. This process is presently performed by manually digitizing points on bone with a pointer and aligning them to a preoperative CT scan. We propose the use of ultrasound to obtain points on bone transcutaneously. A custom-made A-mode probe features a modular lens focusing system and a one-step calibration method. A stable and precise echo detection algorithm is also implemented. The accuracies of three signal detection algorithms—standard deviation, cross-correlation (XCORR) and short-time Fourier transform—were compared using a known reflected signal. XCORR showed the most accurate and stable operation. To test our method of obtaining bone surface points, a plastic model of the fourth human lumbar vertebra was CT scanned and then immersed in a water bath. Six surface registrations of the vertebra using an accurate pointing device were compared to ten registrations obtained using the US probe (using the XCORR algorithm). Student's T-test showed no significant difference in error between the two methods, proving that ultrasound registration, using our method, is equivalent to the more conventional pointer method.

Fractional Fourier transformer of variable order based on a modular lens system

The fractional Fourier transform is a new topic in optics. To make use of the fractional Fourier transform as an experimental tool, I design a fractional Fourier transformer of variable order: I introduce a lens system that is able to perform equidistant fractional Fourier transforms that cover the whole range of orders and that consist of a minimum number of modules. By module, I mean an elementary fractional Fourier transform of certain order that consists of a lens between two free-space lengths. Because of the commutative additivity of the transform, various fractional orders can be achieved by means of different constellations of the modules. It is possible to perform a large variety of fractional Fourier transforms with a small number of modules.