Ultra-Widefield OCT Angiography

Optical Coherence Tomography Angiography (OCTA), a functional extension of OCT, has the potential to replace most invasive fluorescein angiography (FA) exams in ophthalmology. So far, OCTA's field of view is however still lacking behind fluorescence fundus photography techniques. This is problematic, because many retinal diseases manifest at an early stage by changes of the peripheral retinal capillary network. It is therefore desirable to expand OCTA's field of view to match that of ultra-widefield fundus cameras. We present a custom developed clinical high-speed swept-source OCT (SS-OCT) system operating at an acquisition rate 8-16 times faster than today's state-of-the-art commercially available OCTA devices. Its speed allows us to capture ultra-wide fields of view of up to 90 degrees with an unprecedented sampling density and hence extraordinary resolution by merging two single shot scans with 60 degrees in diameter. To further enhance the visual appearance of the angiograms, we developed for the first time a three-dimensional deep learning based algorithm for denoising volumetric OCTA data sets. We showcase its imaging performance and clinical usability by presenting images of patients suffering from diabetic retinopathy.

[Treatment of congenital ptosis in a low-income country: polypropylene frontalis sling at the African Institute of Tropical Ophthalmology]

INTRODUCTION

Treatment of congenital ptosis is exclusively surgical; the frontalis sling method is most appropriate when the ptosis is severe, with no upper eyelid levator function. This surgery typically utilizes various materials (autologous fascia lata, silicone, nylon, or polypropylene bands, etc.).

MATERIALS AND METHODS

This was a retrospective descriptive study of 22 children under 16 years of age, treated for congenital ptosis by frontalis suspension of the levator muscle of the upper eyelid using the polypropylene technique, between January 1, 2014 and June 30, 2017 at the African Institute of Tropical Ophthalmology teaching hospital.

RESULTS

In our study, the surgical result (prior to correction of recurrences) was satisfactory in 81.82 % of cases, with a recurrence rate of 13.64 %. The mean follow-up was 14 months, ranging from 4 to 25 months.

DISCUSSION

The use of polypropylene provides encouraging results in ptosis surgery, while also offering the advantage of being low cost and more available. Its use in developing countries deserves special attention.

Soft dry electroophthalmogram electrodes for human machine interaction

Current soft surface electrodes have attracted more and more attentions owing to their potential applications in biological signal monitoring, human-machine interaction (HMI) and Internet of Things (IoT). The paper presents that soft dry electrode based on polydimethylsiloxane-carbon black (PDMS-CB) conductive polymer is designed and fabricated to continuous, long-term, stable electroophthalmogram (EOG) signal recordings for HMI applications. The features corresponding to the different eye motions are extracted from the EOG data via the soft dry electrodes. Linear discriminant analysis (LDA) recognition algorithms are proposed to recognize eye motion behaviors for controlling the motion of the mobile robots. Experiment results have been demonstrated that LDA recognition algorithm achieves a relatively high recognition accuracy of 90.63% for recognizing four eye movements ('Up', 'Down', 'Right', and 'Left'). The control commands are generated with different eye motions and transmitted to the mobile robot through WiFi communication unit, which the mobile robot is successfully controlled. The soft dry electrodes have the potential in a comfortable, simple, wearable and wireless control of rehabilitation devices.

The effect evaluation of advanced penlight

Pupil diameter measurement is crucial for physical assessment and disease monitoring in a health and nursing care situation. A general penlights (GPLs) is frequently used and allow for an approximate and indirect measurement of the pupil diameter. Health caregivers or nurses generally have less confidence in the value of the pupil diameter measured using the GPL. The Advanced Penlight (APL) is a new device designed for accurate measurement of the pupil diameter. The purpose of the presented research was to compare the accuracies and operational times of the pupil diameter measurements by means of the GPL and APL. One-group post-test and single-blind study designed was used in this study. The innovation of the APL is the addition of a perspective measurement ruler (PMR) attached to one side of the penlight that allows precise measurement of the pupil diameter before and after pupillary contraction. The PMR can be rotated by any angle for adaptation to the measurement conditions. After standard pupil diameter measurements by a refractometer (RM) were performed on a subjects, ninety study participants measured the pupil diameters of the same subject separately by the GPL and APL. A self-administered questionnaire was used to assess the opinions of the participants after using the GPL compare to the APL. The mean age of the participants was 20.01 (SD = 0.47) years and 83% of them were female senior nursing students. There were no statistically significant differences between the average values of pupil diameters measured by the APL and the RM. Compared to the GPL, the pupil diameter measured by APL was much similar to the RM measurement. The average operational time was 8.72 seconds shorter (t = -3.81, p = 0.001) for the APL measurement compared to the GPL measurement. The average scores of convenience and confidence on pupil diameter measurements of questionnaire were higher for the APL compared to the GPL. The APL can increase the accuracy and save operating time of pupil diameter measurement and thereby promote the quality of health assessment and nursing care practice.

Medical Devices; Ophthalmic Devices; Classification of the Intranasal Electrostimulation Device for Dry Eye Symptoms. Final order

The Food and Drug Administration (FDA or we) is classifying the intranasal electrostimulation device for dry eye symptoms into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the intranasal electrostimulation device for dry eye symptoms' classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

A mobile computer aided system for optic nerve head detection

BACKGROUND AND OBJECTIVE

The detection of optic nerve head (ONH) in retinal fundus images plays a key role in identifying Diabetic Retinopathy (DR) as well as other abnormal conditions in eye examinations. This paper presents a method and its associated software towards the development of an Android smartphone app based on a previously developed ONH detection algorithm. The development of this app and the use of the d-Eye lens which can be snapped onto a smartphone provide a mobile and cost-effective computer-aided diagnosis (CAD) system in ophthalmology. In particular, this CAD system would allow eye examination to be conducted in remote locations with limited access to clinical facilities.

METHODS

A pre-processing step is first carried out to enable the ONH detection on the smartphone platform. Then, the optimization steps taken to run the algorithm in a computationally and memory efficient manner on the smartphone platform is discussed.

RESULTS

The smartphone code of the ONH detection algorithm was applied to the STARE and DRIVE databases resulting in about 96% and 100% detection rates, respectively, with an average execution time of about 2 s and 1.3 s. In addition, two other databases captured by the d-Eye and iExaminer snap-on lenses for smartphones were considered resulting in about 93% and 91% detection rates, respectively, with an average execution time of about 2.7 s and 2.2 s, respectively.

Surgical Management of Exudative Maculopathies: Preliminary Report

A new surgical approach to the management of exudative maculopathies has been developed including the transvitreal route. As a result of surgery the subretinal spaces are drained and their viscous content removed. A special tool was designed for this operation. The method has been clinically tested on 32 patients (32 eyes) with different forms of age-related macular degeneration in the phase of complicated pigment epithelium detachment and on six patients (six eyes) with myopic exudative maculopathy. The follow-up ranged from 6 to 32 months. No fluid reappeared in the macular zone in patients with age-related macular degeneration, except one; visual function improved in 26 out of 32 cases (81.3%). Similar results were obtained in all six patients with myopic exudative maculopathy.

Medical Devices; Ophthalmic Devices; Classification of the Tear Electrostimulation Device. Final order

The Food and Drug Administration (FDA or we) is classifying the tear electrostimulation device into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the tear electrostimulation device's classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

Opto-mechanical design of a dispersive artificial eye

We present an opto-mechanical artificial eye that can be used for examining multi-wavelength ophthalmic instruments. Standard off-the-shelf lenses and a refractive-index-matching fluid were used in the creation of the artificial eye. In addition to dispersive properties, the artificial eye can be used to simulate refractive error. To analyze the artificial eye, a multi-wavelength Hartmann-Shack aberrometer was used to measure the longitudinal chromatic aberration and the possibility of inducing refractive error. Off-axis chromatic aberrations were also analyzed by imaging through the artificial eye at two discrete wavelengths. Possible extensions to the dispersive artificial eye are also discussed.

Screening for Diabetic Retinopathy Using a Portable, Noncontact, Nonmydriatic Handheld Retinal Camera

BACKGROUND

Diabetic retinopathy (DR) is a leading cause of low vision and blindness. We evaluated the feasibility of using a handheld, noncontact digital retinal camera, Pictor, to obtain retinal images in dilated and undilated eyes for DR screening. We also evaluated the accuracy of ophthalmologists with different levels of training/experience in grading these images to identify eyes with vision-threatening DR.

METHODS

A prospective study of diabetic adults scheduled to have dilated eye exams at Duke Eye Center from January to May 2014 was conducted. An imager acquired retinal images pre- and postdilation with Pictor and selected 1 pre- and 1 postdilation image per eye. Five masked ophthalmologists graded images for gradability (based on image focus and centration) and the presence of no, mild, moderate, or severe nonproliferative DR (NPDR) or proliferative DR (PDR). Referable disease was defined as moderate or severe NPDR or PDR on image grading. We evaluated feasibility based on the graders' evaluation of image gradability. We evaluated accuracy of identifying vision-threatening disease (severe NPDR or PDR documented on dilated clinical examination) based on the graders' sensitivity and specificity of grading referable disease.

RESULTS

Images were gradable in 86-94% of predilation and 94-97% of postdilation photos. Compared to the dilated clinical exam, overall sensitivity for identifying vision-threatening DR was 64-88% and specificity was 71-90%.

CONCLUSIONS

Pictor can capture retinal images of sufficient quality to screen for DR with and without dilation. Single retinal images obtained using Pictor can identify eyes with vision-threatening DR with high sensitivity and acceptable specificity compared to clinical exam.

The Role of Retinal Imaging and Portable Screening Devices in Tele-ophthalmology Applications for Diabetic Retinopathy Management

In the years since its introduction, retinal imaging has transformed our capability to visualize the posterior pole of the eye. Increasing practical advances in mobile technology, regular monitoring, and population screening for diabetic retinopathy management offer the opportunity for further development of cost-effective applications through remote assessment of the diabetic eye using portable retinal cameras, smart-phone-based devices and telemedicine networks. Numerous retinal imaging methods and mobile technologies in tele-ophthalmology applications have been reported for diabetic retinopathy screening and management. They provide several advantages of automation, sensitivity, specificity, portability, and miniaturization for the development of point-of-care diagnostics for eye complications in diabetes. The aim of this paper is to review the role of retinal imaging and mobile technologies in tele-ophthalmology applications for diabetic retinopathy screening and management. At large, although improvements in current technology and telemedicine services are still needed, telemedicine has demonstrated to be a worthy tool to support health caregivers in the effective management and prevention of diabetes and its complications.

The effectiveness of disc synoptoscope on patients with abnormal binocular vision: a prospective cohort study

PURPOSE

We performed a prospective cohort study to evaluate the effectiveness of disc synoptoscope on binocularity in patients with abnormal binocular vision.

METHODS

39 eligible subjects were recruited for visual therapy with disc synoptoscope in treatment group and 38 were just observed as control.

RESULTS

Simultaneous perception in treatment group was better than controls at 6-month visit (p < 0.05). Fusional amplitude improved in treatment group but decreased in control group at 3- and 6-months visits (p < 0.001). Near and distance stereopsis in treatment group were better than controls at 3- and 6-months (p < 0.05). The improvements of monocular and binocular acuity in treatment group were better than controls at 3- and 6-months (p < 0.05). Postoperative recurrence rate in treatment group was lower than controls (p < 0.05).

CONCLUSION

Visual therapy with disc synoptoscope is effective in improving short-term binocular vision for the patients with abnormal binocular vision; disc synoptoscope could serve as an effective home-based visual therapy instrument.

Medical Devices; Ophthalmic Devices; Classification of Strabismus Detection Device. Final order

The Food and Drug Administration (FDA) is classifying the strabismus detection device into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the strabismus detection device's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Medical Devices; Ophthalmic Devices; Classification of Nasolacrimal Compression Device. Final order

The Food and Drug Administration (FDA) is classifying the nasolacrimal compression device into class I (general controls). The Agency is classifying the device into class I (general controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Medical Devices; Ophthalmic Devices; Classification of the Diurnal Pattern Recorder System. Final order

The Food and Drug Administration (FDA) is classifying the diurnal pattern recorder system into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the diurnal pattern recorder system's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Regionally Discrete Aqueous Humor Outflow Quantification Using Fluorescein Canalograms

PURPOSE

To visualize and quantify conventional outflow directly in its anatomic location.

METHODS

We obtained fluorescein canalograms in six porcine whole eyes and six porcine anterior segment cultures. Eyes were perfused with a constant pressure of 15 mmHg using media containing 0.017 mg/ml fluorescein. Flow patterns were visualized using a stereo dissecting microscope equipped for fluorescent imaging. Images were captured every 30 seconds for 20 minutes for time lapse analysis. Anterior chamber cultures were imaged again on day three of culture. Canalograms were first analyzed for filling time per quadrant. We then wrote a program to automatically compute focal flow fits for each macropixel and to detect convergent perilimbal flow patterns with macropixels grouped into 3 equal-radial width rings around the cornea. A generalized additive model was used to determine fluorescence changes of individual macropixels.

RESULTS

The resulting imaging algorithm deployed 1024 macropixels that were fit to determine maximum intensity and time to fill. These individual fits highlighted the focal flow function. In whole eyes, significantly faster flow was seen in the inferonasal (IN) and superonasal (SN) quadrants compared to the superotemporal (ST) and inferotemporal (IT) ones (p<0.05). In anterior chamber cultures, reduced flow on day 1 increased in all quadrants on day 3 except in IT (p<0.05). Perilimbal ring analysis uncovered convergent perilimbal flow.

CONCLUSIONS

An algorithm was developed that analyzes regional and circumferential outflow patterns. This algorithm found flow patterns that changed over time and differ in whole eyes and anterior segment cultures.

Diabetic Retinopathy Screening Using Telemedicine Tools: Pilot Study in Hungary

Introduction. Diabetic retinopathy (DR) is a sight-threatening complication of diabetes. Telemedicine tools can prevent blindness. We aimed to investigate the patients' satisfaction when using such tools (fundus camera examination) and the effect of demographic and socioeconomic factors on participation in screening. Methods. Pilot study involving fundus camera screening and self-administered questionnaire on participants' experience during fundus examination (comfort, reliability, and future interest in participation), as well as demographic and socioeconomic factors was performed on 89 patients with known diabetes in Csongrád County, a southeastern region of Hungary. Results. Thirty percent of the patients had never participated in any ophthalmological screening, while 25.7% had DR of some grade based upon a standard fundus camera examination and UK-based DR grading protocol (Spectra™ software). Large majority of the patients were satisfied with the screening and found it reliable and acceptable to undertake examination under pupil dilation; 67.3% were willing to undergo nonmydriatic fundus camera examination again. There was a statistically significant relationship between economic activity, education and marital status, and future interest in participation. Discussion. Participants found digital retinal screening to be reliable and satisfactory. Telemedicine can be a strong tool, supporting eye care professionals and allowing for faster and more comfortable DR screening.

[Application of retinal oximeter in ophthalmology]

Retinal oximeter is a new machine which has been used in the diagnose, treatment and research of several ophthalmic diseases for recent years. It allows ophthalmologists to gain retinal oxygen saturation directly. Therefore, retinal oximeter might be useful for ophthalmologists to understand ophthalmic diseases more deeper and clarify the impact of ischemia on retinal function. It has been reported in the literatures that retinal oximeter has potentially useful diagnostic and therapeutic indications in various eye diseases such as diabetic retinopathy, central retinal vein and artery occlusion, retinitis pigmentosa, glaucomatous optic neuropathy, et al. In this thesis, the application of retinal oximeter in ophthalmology is reviewed.

Study of optical design of three-dimensional digital ophthalmoscopes

This study primarily involves using optical zoom structures to design a three-dimensional (3D) human-eye optical sensory system with infrared and visible light. According to experimental data on two-dimensional (2D) and 3D images, human-eye recognition of 3D images is substantially higher (approximately 13.182%) than that of 2D images. Thus, 3D images are more effective than 2D images when they are used at work or in high-recognition devices. In the optical system design, infrared and visible light wavebands were incorporated as light sources to perform simulations. The results can be used to facilitate the design of optical systems suitable for 3D digital ophthalmoscopes.

Medical Devices; Ophthalmic Devices; Classification of the Oral Electronic Vision Aid. Final order

The Food and Drug Administration (FDA) is classifying the oral electronic vision aid into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the oral electronic vision aid's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Fundus Photography in the 21st Century--A Review of Recent Technological Advances and Their Implications for Worldwide Healthcare

BACKGROUND

The introduction of fundus photography has impacted retinal imaging and retinal screening programs significantly.

LITERATURE REVIEW

Fundus cameras play a vital role in addressing the cause of preventive blindness. More attention is being turned to developing countries, where infrastructure and access to healthcare are limited. One of the major limitations for tele-ophthalmology is restricted access to the office-based fundus camera.

RESULTS

Recent advances in access to telecommunications coupled with introduction of portable cameras and smartphone-based fundus imaging systems have resulted in an exponential surge in available technologies for portable fundus photography. Retinal cameras in the near future would have to cater to these needs by featuring a low-cost, portable design with automated controls and digitalized images with Web-based transfer.

CONCLUSIONS

In this review, we aim to highlight the advances of fundus photography for retinal screening as well as discuss the advantages, disadvantages, and implications of the various technologies that are currently available.

Effects of higher-order aberration correction on stereopsis at different viewing durations

To better understand how the eye's optics affects stereopsis, we measured stereoacuity before and after higher-order aberration (HOA) correction with a binocular adaptive optics visual simulator. The HOAs were corrected either binocularly or monocularly in the better eye (the eye with better contrast sensitivity). A two-line stereo pattern served as the visual stimulus. Stereo thresholds at different viewing durations were obtained with the psychophysical method of constant stimuli. Binocular HOA correction led to significant improvement in stereoacuity. However, better eye HOA correction could bring either a bad degradation or a slight improvement in stereoacuity. As viewing duration increased, the stereo benefit approached the level of 1.0 for both binocular and better eye correction, suggesting that long viewing durations might weaken the effects of the eye's optical quality on stereopsis.

3D gaze tracking system for NVidia 3D Vision®

Inappropriate parallax setting in stereoscopic content generally causes visual fatigue and visual discomfort. To optimize three dimensional (3D) effects in stereoscopic content by taking into account health issue, understanding how user gazes at 3D direction in virtual space is currently an important research topic. In this paper, we report the study of developing a novel 3D gaze tracking system for Nvidia 3D Vision(®) to be used in desktop stereoscopic display. We suggest an optimized geometric method to accurately measure the position of virtual 3D object. Our experimental result shows that the proposed system achieved better accuracy compared to conventional geometric method by average errors 0.83 cm, 0.87 cm, and 1.06 cm in X, Y, and Z dimensions, respectively.