Open Eye Research Articles

Numerical evaluation of bidirectional high-speed data transmission over turbulence tolerable FSO link employing WDM-OAM multiplexing and DP-QPSK modulation techniques

Orbital angular momentum (OAM) mode multiplexing is achieving utmost interest for the enhancement of transmission capacity and spectral efficiency. We have reported a (2 × 8 × 112 Gbps) 1792 Gbps bi-directional FSO link based on WDM-OAM multiplexing and dual-polarization quadrature phase-shift keying (DP-QPSK) modulation technique. An optical frequency comb lines (OFCL) generator, capable to generate 44 comb lines with flatness∼0 dB is employed as a broadband laser source. The efficiency of the system is not only checked for clear weather but also for different turbulence situations (weak, moderate, and strong atmospheric turbulence). According to the best of our knowledge, this is the first one where the effect of atmospheric turbulence on DP-QPSK data carrying OAM modes has been checked for a bidirectional link. The combination of coherent detection with digital signal processing is utilized for compensating wave-form distortion and noise cancellation due to atmospheric turbulence. A very low power penalty of 1.65 dB in clear weather and 4.91 dB in strong atmospheric turbulence at a BER∼10 −9 with open eye and clear constellation diagrams depicts the feasibility of the proposed system.

Analisis Tingkat Pemborosan Waktu Pelayanan Poli Mata Dengan Value Stream Mapping Dan Value Stream Analysis Pada RSU Muhammadiyah Ponorogo

Muhammadiyah Ponorogo General Hospital is one of the private hospitals in Ponorogo Regency. At this time the Muhammadiyah Ponorogo General Hospital has received Plenary accreditation from the Indonesian Hospital Accreditation Institute (LARSI). The problem that is often faced by hospitals is that there is a lot of waste that occurs in the service process at the Eye Polyclinic of RSU Muhammadiyah Ponorogo. The most critical level of waste for eye polyclinic services is waiting with a weighting value of 4.00, waste inventory with a value of 3.16, waste overproduction with a weighting value of 3.00, waste defects with a weighting value of 2.91 , waste inappropriate processing with a weight value of 2.66, waste unnecessary motion with a weight value of 2.58, waste transportation with a weight value of 1.41, and waste underutilized abilities of people with a weight value of 2.25. The initial activity time before the repair was 14,677 seconds or 244 minutes (4 hours) and after the repair was reduced to 6,577 seconds or 109 minutes (1 hour 61 minutes). The highest waste is waiting, namely doctors often do not come on time and there is a lack of nurses or pharmacists in the pharmacy with a Risk Priority Number (RPN) score of 252 and 224. Recommendations for improvement that can be proposed are adding doctors to the eye poly department to reduce doctor delays because there are surgery schedules that often collide with the schedule for opening eye poly services and adding medical personnel to the pharmacy department, to reduce queues you can use a drug delivery application that can be accessed by patients without having to queue again at the hospital.

Left or right, that is the question: use of egocentric frame of reference and the right-eye advantage for understanding gestural signs in bottlenose dolphins (Tursiops truncates).

How do bottlenose dolphins visually perceive the space around them? In particular, what cues do they use as a frame of reference for left-right perception? To address this question, we examined the dolphin's responses to various manipulations of the spatial relationship between the dolphin and the trainer by using gestural signs for actions given by the trainer, which have different meanings in the left and right hands. When the dolphins were tested with their backs to the trainer (Experiment 1) or in an inverted position underwater (Experiments 2 and 3), correct responses from the trainer's perspective were maintained for signs related to movement direction instructions. In contrast, reversed responses were frequently observed for signs that required different sounds for the left and right hands. When the movement direction instructions were presented with symmetrical graphic signs such as " × " and "●", accuracy decreased in the inverted posture (Experiment 3). Furthermore, when the signs for sounds were presented from either the left or right side of the dolphin's body, performance was better when the side of the sign movement coincided with the body side on which it was presented than when it was mismatched (Experiment 4). In the final experiment, when one eye was covered with an eyecup, the results showed that, as in the case of body-side presentation, performance was better when the open eye coincided with the side on which the sign movement was presented. These results indicate that dolphins used the egocentric frame for visuospatial cognition. In addition, they showed better performances when the gestural signs were presented to the right eye, suggesting the possibility of a left-hemispheric advantage in the dolphin's visuospatial cognition.

Process optimization of bottom-blown argon for 130t ladle furnace

ABSTRACT A quarter scale water model experiment is employed to investigate the effect of single and double porous plug placement and blowing flow rates on the mixing time, slag eye area, and slag entrapment depth. As a result, when the blowing flow rate is greater than 180 L min–1, the blowing effect of double blowing plugs is better than that of single blowing plugs. The open eye area and slag entrapment depth in the double blow plug arrangement are smaller than that in the single blow plug arrangement. In general, the ladle refining effect is better when the blow plug is arranged at 0.4R position and the angle between the two blow plugs is 120°. The final recommended argon blowing process is 240–300 L min–1 for the heating and alloying process and 60–120 L min–1 for the soft blowing process, respectively.

800 Gbit/s QSFP-DD Transceiver Based on Thin-Film Lithium Niobate Photonic Integrated Circuit

800G Ethernet is expected to be the dominant solution for the next generation inter- and intra-data-center connections. To boost the transmission capacity to 800Gb/s, utilizing multi-level pulse amplitude modulation (PAM) transmitting format and adopting multiple lanes are competitive solutions. In this paper, we demonstrate a PAM4-modulated 800G QSFP-DD transceiver integrated with two 4×100G thin-film lithium niobate (TFLN) DR4 modulator chips. The DR4 modulator chips have a 13.5 dB insertion loss (including the inherent 3 dB modulation loss and 6 dB splitting loss) and one DR4 chip requires one 17 dBm light source. The EO response has a 40 GHz bandwidth at 2.3 dB and the electric reflection keeps below -12 dB. The eight channels of 800G transceiver have a clear open eye patterns at 1.5 Vpp driving voltage under 53.125 Gbaud PAM-4 modulation with all the ERs above 4.03 dB and TDECQ's below 2.13 dB. The sensitivity of the receiver is around -8.6 dBm after 2 km and back-to-back transmission with the BER of all the channels below the DR4 forward error correcting threshold. It is demonstrated that our 800G QSFP-DD transceiver meets 400GBASE-DR4 standards and packaging requirements simultaneously. This is the first time that 4×100G DR4 modulator array based on TFLN and 800G QSFP-DD transceiver based on TFLN are reported to the best of our knowledge.

Имплантация интраокулярной линзы при травматической катаракте: сроки и перспективы

A prospective randomized clinical trial included 30 patients (60 eyes) with traumatic cataract after open eye injury. Patients were divided into 2 groups depending on the time of the operation. The first (n = 15, 30 eyes) was an early operation (1–3 days after the injury). The second (n = 15, 30 eyes) is a late operation (6 or more days after the injury). Research methods – measurement of visual acuity, intraocular pressure (IOP), assessment of inflammation of the anterior chamber, position of the intraocular lens (IOL), etc. The study period was 1, 3, and 6 weeks after surgical treatment. It was revealed that visual acuity with the best correction was noted 6 weeks after the early operation. Also in the group of early cataract surgery, the frequency of postoperative complications (rupture of the posterior capsule, increased IOP, inflammation of the anterior chamber, IOL opacity, posterior synechia, IOL subluxation and pigment deposition on the IOL) was significantly lower than in the late surgery group (p < 0.05). It is recommended to perform cataract surgery and IOL implantation after open eye injuries at an early stage. Keywords: surgery, traumatic cataract, vision, intraocular lens implantation

Surgical needles with handles

Having given examples of hand-held surgical needles and of needle holders of various types, we can consider a few needles that are mounted on handles. Greco-Roman and Arabic sources described ornately handled eyeless needles for displacing cataracts for use in the technique of couching. Also of historical origin are the various types of acupuncture needle. In 1564, Ambroise Paré illustrated a robust handled needle, which had an eye part way along the needle, through which were passed gold or lead ligatures, used during hernia repair. Handled needles have sharp or blunt tips, the latter for passing ligatures around structures to be tied off, such as pedicles or individual blood vessels. Hand-held needles have proximal eyes, whereas handled needles have distally placed eyes. This allows ligatures to be applied at some depth by one of two methods: passing ligature-loaded needles through tissues to be ligated or, passing the ‘empty’ needle through tissues and then loading the needle by feeding the ligature into a closed or open eye manually by an assistant or, rarely, by using a mounted ligature holder. The needle then is carefully withdrawn and the ligature tied on each side of the pedicle. These now rather historical instruments were frequently used in pelvic surgery by gynaecologists or urological surgeons. The longer reaching needle is clearly useful when working in other rather inaccessible areas, for example, when repairing vesicovaginal fistulas or cleft palates.

Visible-Light Integrated PIN Avalanche Photodetectors With High Responsivity and Bandwidth

Integrated photodetectors are key building blocks of scalable photonics platforms. Many recent improvements have been made for integrated avalanche photodetectors (APDs) operating at infrared telecommunications wavelengths, but their visible-spectrum counterparts remain relatively unexplored. Here, we demonstrate PIN-doped silicon APDs for visible light detection, monolithically integrated with a silicon nitride photonics circuit via end-fire coupling. An in-depth study of multiple PIN doping profiles reveals different optimal designs based on the desired operating regimes. At −49 dBm input power, they show 0.25 A/W (0.8 A/W) responsivity at reverse bias as low as 0.5 V (5.5 V), with corresponding dark current of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 3 pA (50 pA). We also report fast RF response with an optimal 3 dB bandwidth of 11 GHz and gain-bandwidth product of 142 GHz, with all devices yielding open eye diagrams at 25 Gbps or above. Coupled with CMOS-compatible fabrication, our APDs will enable scalable photonics applications in sensing, communications, and quantum technologies at visible wavelengths.

Surgical Rehabilitation of a Posttraumatic Iris Cyst, Cataract and Astigmatism Patient

Injuries cause serious disturbance of the form and function of the organ of vision due to the damage and accompanying or remote complications and therefore have a high proportion to the structure of low vision, blindness and disability. One of the complications of penetrating wounds of the eye is iris cysts. Iris cyst can increase and cause pupillary block, secondary glaucoma, uveitis, corneal dystrophy, and therefore it requires surgical intervention. The goal of surgical treatment of an iris cyst is to ensure complete removal of the cyst.Objective: to estimate the clinical and functional results of treatment in a posttraumatic iris cyst, posterior subcapsular cataract and myopic astigmatism patient.Patient and methods. Patient B., 49 years old with posttraumatic retention iris cyst, posterior subcapsular cataract, compound myopic high astigmatism was examined. To determine the tactics of surgical treatment of the patient, a complex of General ophthalmology was performed (visometry, IOP measurement, autorefractometry, biomicroscopy, ophthalmoscopy), as well as special (B-scanning, optical coherence tomography of the retina) research methods. The follow-up period was 1 year.Results and discussion. To improve visual functions and prevent the development of secondary glaucoma, the patient was offered surgery — excision of the iris cyst and cataract phacoemulsification with toric intraocular lens. Simultaneous carrying out of two stages of the operation reduced the risks of postoperative complications and shorten the rehabilitation period.Conclusion. Positive optical and therapeutic effects were achieved as a result of the surgical treatment 44 years after an open eye injury: the eye is calm, the iris cyst is not detected, visual acuity has increased. The postoperative period showed the saving the stable and high visual and functional result with no recurrence of the iris cyst.

High-Speed Waveguide-Integrated Avalanche Photodiodes for Near-Infrared Wavelengths on SiN-on-SOI Photonic Platform

Recently, there have been efforts on developing monolithically integrated avalanche photodiodes (APDs) for visible and near-infrared (NIR) wavelengths. However, the fabrication of these detectors in commercial photonic foundries often requires custom integration flow due to many design rule violations in standard integration process. This increases the fabrication cost, hinders the use of highly robust integration platform, and prevents access to well-mature process design kits. Here, we report on waveguide-integrated APDs operating at 850 nm by utilizing a commercial silicon nitride-on-silicon-on-insulator (SiN-on-SOI) photonics platform with no process modifications. Our devices comprise a SiN waveguide for input light routing and an SOI layer underneath to form APDs. We examine the effect of different junction parameters and device length on DC and high-speed device performance. We demonstrate high gain-bandwidth product up to 120 GHz with low dark current of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{&lt; }$</tex-math></inline-formula> 25 nA and high responsivity that can reach 0.71 A/W, and observe open eye diagrams at up to 40 Gbps for all device variations. The performance parameters are on-par or even superior when compared to other integrated APDs operating in the NIR wavelengths. Being compatible with the standard integration flow of a multi-project wafer service of a commercial foundry, our devices are readily accessible, and they expand the functionalities of well-mature SiN-on-SOI photonics platform for applications ranging from optical interconnects, LIDAR, visible light communication to biosensing and quantum applications.

All-silicon microring avalanche photodiodes with a >65 A/W response.

We report an all-Si microring (MRR) avalanche photodiode (APD) with an ultrahigh responsivity (R) of 65 A/W, dark current of 6.5 µA, and record gain-bandwidth product (GBP) of 798 GHz at -7.36 V. The mechanisms for the high responsivity have been modelled and investigated. Furthermore, open eye diagrams up to 20 Gb/s are supported at 1310 nm at -7.36 V. The device is the first, to the best of our knowledge, low cost all-Si APD that has potential to compete with current commercial Ge- and III-V-based photodetectors (PDs). This shows the potential to make the all-Si APD a standard "black-box" component in Si photonics CMOS foundry platform component libraries.

Experience-dependent functional plasticity and visual response selectivity of surviving subplate neurons in the mouse visual cortex

Subplate neurons are early-born cortical neurons that transiently form neural circuits during perinatal development and guide cortical maturation. Thereafter, most subplate neurons undergo cell death, while some survive and renew their target areas for synaptic connections. However, the functional properties of the surviving subplate neurons remain largely unknown. This study aimed to characterize the visual responses and experience-dependent functional plasticity of layer 6b (L6b) neurons, the remnants of subplate neurons, in the primary visual cortex (V1). Two-photon Ca2+ imaging was performed in V1 of awake juvenile mice. L6b neurons showed broader tunings for orientation, direction, and spatial frequency than did layer 2/3 (L2/3) and L6a neurons. In addition, L6b neurons showed lower matching of preferred orientation between the left and right eyes compared with other layers. Post hoc 3D immunohistochemistry confirmed that the majority of recorded L6b neurons expressed connective tissue growth factor (CTGF), a subplate neuron marker. Moreover, chronic two-photon imaging showed that L6b neurons exhibited ocular dominance (OD) plasticity by monocular deprivation during critical periods. The OD shift to the open eye depended on the response strength to the stimulation of the eye to be deprived before starting monocular deprivation. There were no significant differences in visual response selectivity prior to monocular deprivation between the OD changed and unchanged neuron groups, suggesting that OD plasticity can occur in L6b neurons showing any response features. In conclusion, our results provide strong evidence that surviving subplate neurons exhibit sensory responses and experience-dependent plasticity at a relatively late stage of cortical development.

Secondaries from retromolar trigone carcinoma leading to orbital apex disorders

Orbital apex disorders (OADs) are uncommon and they include – orbital apex syndrome (OAS), superior orbital fissure syndrome (SOFS), and cavernous sinus syndrome (CSS). They all share similar etiologies, diagnostic evaluation, and management strategies. These syndromes can occur isolated or combined – where SOFS progresses and develops into OAS or CSS. Combined presentation has been reported with infective etiologies, but no literature is available for neoplasms. OAD secondary to head and neck cancer is exceptionally rare. A 44-year-old male post left hemi-mandibulectomy with modified neck dissection, radiotherapy, and chemotherapy for left retromolar trigone carcinoma presented with complaints of inability to open left eye (LE) and defective vision in the same eye. On examination of LE, visual acuity was 6/24 NIP with complete ptosis, extraocular movements were restricted in all gaze, corneal sensation was diminished, and pupil was 5 mm and not reacting to light. LE fundus examination showed blurring of disk margins. The primary diagnosis was made as OAS. Contrast enhanced-MRI neck showed features suggestive of recurrence with intracranial extend involving left cavernous sinus, orbital apex, and left orbit. Later considering the extend of spread in MRI and the clinical presentation, diagnosis was made to be OAD. The patient was given third cycle of chemotherapy – injection paclitaxel, injection cisplatin, and injection fluorouracil, along with injection dexamethasone. The patient was provided temporary eye crutch glasses and asked to review after 3 weeks for repeat assessment. Although individual syndromes of OAD are rare, they are closely related entity. Hence, it is important to know that SOFS can progress to OAS causing visual dysfunction or to CSS, leading to systemic ailments. Or else, they can present as combined syndromes also.

Heterogeneous integration of a GaN-based photonic integrated circuit with an Si-based transimpedance amplifier.

The heterogeneous integration of a GaN-based photonic integrated circuit (PIC) and an Si-based transimpedance amplifier (TIA) is demonstrated in this work. The monolithic GaN PIC, fabricated from a GaN-on-Si light-emitting diode (LED) wafer, comprises LEDs whose optical outputs are coupled to photodetectors (PD) through suspended waveguides. The PIC chip is mounted onto a printed circuit board together with a TIA chip and two filter chip capacitors, occupying a compact footprint. The components are interconnected directly using wire-bonds to minimize signal delays and attenuation. The integrated system achieves rise and fall times of 2.21 and 2.10 ns, respectively, a transmission delay of 3.54 ns, and a bandwidth exceeding 390 MHz. Transmission of a pseudorandom binary sequence-3 (PRBS-3) signal across the integrated system is also demonstrated at the data transmission rate of 280 Mbit/s with a clearly resolved open eye diagram.

Design a remote sensing of multi-BOTDR fiber optic sensors for fuel pipeline monitoring

The necessity for environmental protection has led to the development of different sensors for monitoring fuel pipelines to avoid explosion, leakage, and corrosion. Distributed optical fiber sensors-based Brillouin scattering have become progressively common because of their novel feature of simultaneously determining temperature, vibration, and strain. The stimulated Brillouin scattering (SBS) threshold power, sensing distance, single-mode fiber cable length, and sensing accuracy are serious parameters to the implementation of Brillouin optical time-domain reflectometry (BOTDR) sensor. In this study, remote sensing of multi-BOTDR fiber optic sensors for fuel pipeline monitoring is designed and presented. The results of simulations and theoretical explainations on suppressing fiber optic nonlinearity are analyzed. Results show that an SBS suppression via 16 dB is required to attain the maximum multi-remote sensing distance of up to 20 km for each network and a perfect frequency shift of 11 GHz. An open eye pattern corresponds to minimal signal distortion with a high Q-factor of 22 for the developed sensor. The highest sensing accuracy of 0.3318 %/K indicating power change (%) is observed from 290–300 K at 193.1 THz operating frequency.

Intraocular foreign body (IOFB)

Intraocular foreign bodies (IOFBs) were 16-40% of open globe trauma and could cause severe visual loss. Therefore, they require immediate diagnosis and treatment. This is a case of an 18-year-old man who came to the hospital complaining of a metal piercing in his left eye while cutting some metal about 2 hours before entering the hospital. On ophthalmologic examination, visual acuity of the left eye was 3/60, and a full-thickness laceration of the cornea with an IOFB was seen at the anterior chamber base. Immediate IOFB evacuation was carried out on the same day as the incident happened. During the operation, a metal intraocular foreign body with a sharp tip, 4x2x1 mm in size, was successfully removed in intact condition. Next, the laceration and the corneal limbus incision were sutured using 10.0 nylon. The stitches are tight, and the anterior chamber depth is maintained. Evaluation on the fourth week after IOFB evacuation showed that visual acuity in the left eye was 6/20 with lens correction C-1.50 x 150° become 6/7.5. Appropriate and prompt diagnosis and management of open eye injury can contribute to preserving a good anatomical and functional result.

Modern trends in tear replacement therapy for patients with dry eye syndrome

Today, the dry eye syndrome therapy is based on the techniques aimed at compensating for loss of moisture in the conjunctival cavity (the so-called tear replacement therapy) either by additional moistening of the eye surface, or by maintaining the moisture in the conjunctival cavity. Traditionally, the first step is to moisturise the eye surface, and the artificial tear products is the leader in this area. In recent years, natural mucopolysaccharides are one of the basic components of artificial tears that attract the greatest practical interest, and among them is the hyaluronic acid, or rather its sodium salt, which is almost identical in pharmacological properties to native hyaluronic acid with the respective molecular weight. Hyaluronic acid is characterized by high mucoadhesiveness, which allows the artificial tear solution based on this polymer to bind to mucins on the eye surface and prolong the residence time of the formulation on the ocular surface. The even more significant property of high molecular-weight HyA is the so-called thixotropy: the high molecular-weight HyA has a high viscosity on the open eye, which provides good wettability of the ocular surface. Today, preservative-free solutions based on the hyaluronic acid sodium salt, which are characterized by high thixotropy, hygroscopicity, mucoadhesiveness and good tolerability, are the priority. The high effectiveness of such drugs has been established. They provide deep hydration in the treatment of dry eye syndrome due to Sjögren's syndrome, meibomian blepharitis and perimenopause, as well as dry eye syndrome in children. The latter was developed due to neuroparalytic keratitis, chronic blepharitis, and systematic damage to the ocular surface by eye drops containing preservatives.

Anthropometric Profile and Physical Activity Level as Predictors of Postural Balance in Overweight and Obese Children.

Overweightness and obesity can negatively influence many activities, including postural balance and locomotion, increasing predisposition to injury and risk of falls due to limitations on the biomechanics of daily living. The present study aimed to determine the influence of the anthropometric profile and physical activity level (PAL) on the postural balance of overweight and obese children. The sample included 387 schoolchildren (216 boys and 171 girls). The variables of the anthropometric profile studied were body mass, biped height, BMI, waist circumference, waist-to-hip ratio (WHR), summation of folds, body composition, and somatotype. PAL was measured using the PAQ-C questionnaire. Static and dynamic postural balance were measured through an open-eye (OE) and closed-eye (CE) posturographic test and the SEBTm, respectively. For static balance, the significant models were for mediolateral velocity (R2 = 0.42 in OA; R2 = 0.24 in OC), anteroposterior velocity (R2 = 0.21 in OA; R2 = 0.27 in OC), and mean velocity (R2 = 0.27 in OA; R2 = 0.46 in OC), where the predictors of low performance were younger age, male sex, overweight/obese nutritional status, greater thickness of skin folds, less tendency to mesomorphy, and greater fat mass. On the other hand, for dynamic postural balance, the significant models were observed in the previous direction (R2 = 0.39), posteromedial (R2 = 0.57), and posterolateral (R2 = 0.56), where the variables that predict a low performance were low PAL, overweight/obese nutritional status, and high WHR. Overweight and obese children presented a deficit in static and dynamic postural balance, enhanced by variables such as gender, age, PAL, and anthropometric characteristics related to adiposity.

Școala online în ciclul primar: Perspective ale profesorilor, elevilor, părinților

Part of the life of the society in which it develops and on which it has an impact perhaps not always fully assumed and respected, the school benefits both from the scientific structure and from the tendency - natural and necessary - to investigate the new. So how do we deal with the digital reality that students live in and that even the most conservative of teachers can't dissociate themselves from? Here is the plot of this work! In this context, the purpose of this work is to investigate and assess the impact of online schooling on Romanian grounds, following the opinions of the three active educational performers immerged in it the most: teachers, pupils, parents. The inquiry has followed the primary education learning path, as part of a deeper concern for this field, with an open eye towards both achievements and challenges. The questionnaires have given the possibility to all three categories to express personal perspectives and conclusions. The reasonable deduction of the present educational approach is that online courses represent a milestone in the functioning of Romanian schools, providing us with the ability to acknowledge the importance of both direct interaction and need to develop acquires in terms of technology.

75 GHz germanium waveguide photodetector with 64 Gbps data rates utilizing an inductive-gain-peaking technique

High-performance germanium (Ge) waveguide photodetectors are designed and fabricated utilizing the inductive-gain-peaking technique. With the appropriate integrated inductors, the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity. Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed. In this work, the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated, which indicates the high-speed performance of photodetectors using the inductive-gain-peaking technique.