Technical Report: A New Device Attached to a Smartphone for Objective Vision Screening.

SIGNIFICANCE: A new device attached to a smartphone was created for objective vision screening of young children including infants and newborns. The device is compact, lightweight, portable, cost-effective, and easy to operate. Therefore, it is suitable for screening large numbers of children in clinical settings, schools, and communities. PURPOSE: This article introduces a new device attached to a smartphone for objective vision screening. It can detect and categorize significant refractive errors, anisometropia, strabismus, cloudy ocular media, and ptosis that may cause amblyopia. METHODS: The new device applies the same principles as conventional streak retinoscopy but examines both eyes simultaneously and records the results electronically. The device comprises optical elements that produce a precise streak light beam and move it across a child's both eyes. The smartphone's video camera catches and records the motion of retinal reflex inside the child's pupils. By observing the direction of motion of the retinal reflex relative to the light beam motion, as well as its speed, width, and brightness, the examiner is able to assess the individual and comparative refractive status, ocular alignment, and other conditions. RESULTS: Vision screening with this device does not require any subjective response from children. The examination can be performed and analyzed by nonprofessionals after a short learning period of time. Because the examination results are electronically recorded by the smartphone, they can be stored in the child's files and sent out for professional consultations. CONCLUSIONS: The new device will provide the same functions as conventional streak retinoscopy but examines a child's both eyes simultaneously, so that, in addition to categorizing refractive errors and assessing clarity of refractive media of the eyes, it can also detect anisometropia, strabismus, and anisocoria. In addition to showing the examination results on the smartphone's screen, the device can also store the results electronically.

Accuracy of Focal Laser Treatment Based on External Imaging (OCT) Using a Navigated Retinal Laser System - a Case Series.

Background The navigated laser photocoagulation system (NAVILAS®, OD-OS GmBH, Teltow, Germany) is a laser treatment device that provides navigated laser treatment of the retina based on a fundus image. The purpose of this study was to investigate the accuracy of laser treatment based on external optical coherence tomography (OCT) images - a new application of the device. Patients and Methods This retrospective case series evaluated the accuracy of laser spot placement in 7 eyes after using overlaid external OCT images for planning NAVILAS laser treatment. After a mean time of 33 days, a post-treatment OCT was obtained and compared with the pretreatment plan on the previous OCT. Laser spots touching or overlapping the planned 100 µm laser spots were classified as "match" and invisible laser spots as "laser spot not evolved". Results A total of 477 laser spots in 7 eyes were evaluated (mean: 68 spots per eye). Of all planned laser spots, 361 (75.7 %) were visible on post-treatment OCT. 58.7 % of these spots matched the pretreatment plan. Non-matching laser spots showed no uniform pattern of dislocation. Conclusions Planning navigated NAVILAS Laser treatment based on manually imported OCT images seems to be less accurate than planning with NAVILAS integrated imaging. These findings warrant further evaluation, not only regarding the recently installed automated picture importing tool but also concerning its clinical impact, which is possibly outweighed by the advantages of the additional image information.

[Handheld Optical Coherence Tomography in Paediatric Ophthalmology: Experience of the Department of Ophthalmology in Giessen]. / Handgehaltene optische Kohärenztomografie in pädiatrischer Ophthalmologie: Erfahrung der Gießener Universitätsaugenklinik.

Introduction: Optical coherence tomography is an important tool for the imaging and analysis of retinal structures. The usability of conventional table-top devices is limited in children. We report on our experiences with a handheld Spectral Domain Optical Coherence Tomography (HH-SD-OCT, Bioptigen™) in infants and young children in our daily practice. Methods: Between October 2014 and April 2016, we investigated 259 patients. Indications and diagnoses were assessed. Individual examples are shown to demonstrate the advantages and disadvantages of the novel technique. Results: It was possible to examine 259 children of at least 7 weeks of age (median: 1.59 years; ± 1.32 SD) with a mean investigation time of 18.3 minutes (± 8.3 SD). The most frequent indication was retinal assessment in prematures (32.8 %). Nystagmus, retinal dystrophies, reduced visual acuity and albinism amounted to additional 37.4 % of all indications. Conclusions: Handheld OCT is a beneficial complement for diagnosis of diseases in paediatric ophthalmology. As a complement to established methods like wide-field fundus photography, HH-SD-OCT allows the physician to assess and follow-up new objective structural information. As the Bioptigen does not have an eye tracker, it is challenging to orient the scan in the posterior retinal pole, in particular in case of instable fixation. This complicates follow-up investigations, which can only be performed with additional high programming and analysis effort.

[Retinal OCT: Vitreoretinal Interface]. / Netzhaut-OCT: vitreoretinale Grenzfläche.

The gold standard for the assessment of the vitreoretinal interface (VRI) is high resolution OCT. It is therefore essential to select the appropriate scan modalities to detect all morphological changes in different diseases, not only at the VRI, but also in all layers of the retina and in the foveal and parafoveal areas. These can be raster scans, radial scans or "en face" scans. Morphological changes at the VRI and especially in the outer retinal layers are good prognostic factors in high resolution OCT for the success of surgery for vitreomacular interface disorders. The following article gives an overview of current OCT procedures as well as correlations between morphological and functional findings.

High-speed adaptive optics for imaging of the living human eye.

The discovery of high frequency temporal fluctuation of human ocular wave aberration dictates the necessity of high speed adaptive optics (AO) correction for high resolution retinal imaging. We present a high speed AO system for an experimental adaptive optics scanning laser ophthalmoscope (AOSLO). We developed a custom high speed Shack-Hartmann wavefront sensor and maximized the wavefront detection speed based upon a trade-off among the wavefront spatial sampling density, the dynamic range, and the measurement sensitivity. We examined the temporal dynamic property of the ocular wavefront under the AOSLO imaging condition and improved the dual-thread AO control strategy. The high speed AO can be operated with a closed-loop frequency up to 110 Hz. Experiment results demonstrated that the high speed AO system can provide improved compensation for the wave aberration up to 30 Hz in the living human eye.

Precision of the retinal tomograph as a screening device.

PURPOSE: To assess the diagnostic accuracy of the Heidelberg Retinal Tomograph 3 (HRT3) as a screening device in comparison with the reference standard of Octopus standard automated perimetry results (SAP) combined with clinical findings. METHODS: All patients underwent screening examinations and investigations within a single day. Abnormal screening results were classified as follows: The HRT3: Either "borderline" or "outside normal limits" using the global Moorfields classification (MFC); SAP and clinical exam: A mean defect>2.4 dB or "outside normal limits" clear text analysis of SAP; and one of the following i) IOP>21 mmHg, ii) Van Herrick<», iii) cup disc ratio>0.55, iv) optic nerve head abnormality, v) narrow iridocorneal angle or vi) evidence of peripheral anterior synechiae on gonioscopy. RESULTS: The mean age of the participants was 59.9 years (±14.8 [21, 91]). Twenty-three subjects (16%) were classified as abnormal on SAP and clinical exam. The HRT3 classification had a sensitivity of 30% (95% CI [16%, 51%]) with associated specificity of 58% (95% CI [49%, 66%]). Of the sixty subjects classified as borderline or outside normal limits with the HRT MFC global result, seven subjects were also abnormal according to SAP and clinical exam. CONCLUSION: The results suggest that the HRT3 may not be suitable as a sole screening device; however, further investigation is necessary.

A comparison of a traditional and wavefront autorefraction.

PURPOSE: To evaluate the agreement between the autorefraction function of the Canon RK-F2, an autorefractor/keratometer based on the ray deflection principle, and the Carl Zeiss Vision i.Profiler(Plus), an wavefront aberrometer, compared with each other and with a noncycloplegic subjective refraction. METHODS: Objective refraction results obtained using both instruments were compared with noncycloplegic subjective refractions for 174 eyes of 100 participants. Analysis of sphere, cylinder, and axis using spherical equivalent difference and a new measurement, cross-cylinder difference, was performed. The spherical equivalent refraction and cross-cylinder difference for the manifest refraction were compared using Bland-Altman limits of agreement and 95th percentile analysis. RESULTS: The 100 participants represent 52 women and 48 men with a mean (±SD) age of 51.7 (±13.8) years, an average (±SD) spherical power of -0.67 (±2.53) diopters (D), and an average (±SD) cylinder power of -0.94 (±0.87) D. The spherical equivalent difference is 0.03 D (Canon) and -0.11 D (Zeiss). The 95% limits of agreement for the spherical equivalent are -0.69 to 0.75 D (Canon) and -0.75 to 0.75 D (Zeiss). The mean cross-cylinder power difference is -0.08 D (Canon) and 0.02 D (Zeiss). The 95% limits of agreement for the cross-cylinder power difference are 0.63 to 0.50 D (Canon) and 0.49 to 0.75 D (Zeiss). The mean axis power difference is -0.04 D (Canon) and 0.05 D (Zeiss). The 95% limits of agreement for axis power difference are -0.71 to 0.63 D (Canon) and -0.78 to 0.78 D (Zeiss). The double-angle astigmatic plot center of distribution for the RK-F2 is 0.035 D at 70 degrees, and that for the i.Profiler(Plus) is 0.053 D at 32 degrees. CONCLUSIONS: Both instruments provided clinically useful spherical equivalent refractive data compared with a subjective refraction, whereas the Canon RK-F2 was slightly more accurate in determining the cylinder power compared with a subjective refraction.

Evaluation of diabetic retinopathy screening using a non-mydriatic retinal digital camera in primary care settings in south Israel.

To evaluate the effectiveness of the non-mydriatic digital camera for diabetic retinopathy (DR) screening. Secondary purposes of the study were to characterize diabetic patients being screened for the presence of DR and to calculate the sensitivity, specificity, and positive predictive value of the test. All 6,962 consecutive patients with type 2 diabetes undergoing non-mydriatic digital retinal photography between January 1, 2009 and June 30, 2010 in eight community health clinics in the south of the country were included. Comparison of a random sample of patients who underwent non-mydriatic retinal photography, and who were also examined by an ophthalmologist with pupil dilation was also performed. The average age of all patients was 64.2 years. A total of 5,960 cases (85.6 % of all photographs) were of adequate quality for the diagnosis. DR of any degree was found in 1,092 (18.3 %) patients. Normal fundus pictures were found in 49.4 % of patients. In 32.2 % of cases, non-DR pathologies were found. Among cases in which DR was found, 73.3 % (801 cases) had mild non-proliferative retinopathy (NPDR), 7.1 % (77 cases) had moderate NPDR, 6.8 % (74 cases) had proliferative retinopathy, and 12.8 % (140 cases) had diabetic macular edema. Older patients had more chance of having poor quality pictures (p < 0.001 between patients older and younger than 70 years). When non-mydriatic fundus photography was compared with dilated fundus examination by an ophthalmologist, sensitivity of 99.3 %, specificity of 88.3 %, and positive predictive value of 85.3 % were found. Non-mydriatic digital retinal photography is an efficient method for DR screening. The test has high sensitivity and specificity. The test, as performed in community health centers in the south of the country, contributed to the early diagnosis of >1,000 cases of DR. Many patients can be followed up in a fast and efficient way, although the test cannot replace a complete eye examination after pupil dilation mainly in older people. Other non-DR sight-threatening ocular pathologies can be also detected.

Peripheral Refraction Using Ancillary Retinoscope Component (P-ARC).

Purpose: To assess the agreement of retinoscope-based peripheral refraction techniques with the criterion standard open-field autorefractor. Methods: Fifty young adults (mean age, 24 ± 3 years) participated in this study. Two masked, experienced senior examiners carried out central refraction and peripheral refraction at the temporal 22° (T22°) and nasal 22° (N22°) eccentricities. Peripheral refraction techniques were (a) peripheral refraction using ancillary retinoscope component (P-ARC), (b) retinoscopy with eye rotation, and (c) open-field autorefractor. Peripheral refraction with retinoscopy values was compared with an open-field autorefractor (Shinn Nippon NVision-K) to assess the agreement. All measurements were taken from the right eye under noncycloplegic conditions. Results: The mean difference ±95% limits of agreement of peripheral refraction values obtained using P-ARC from T22° (+0.11 diopters [D] ± 1.20 D; P = 0.20) or N22° (+0.13 D ± 1.16 D; P = 0.13) were comparable with open-field autorefractor. The eye rotation technique compared to autorefractor showed a significant difference for T22° (+0.30 D ± 1.26 D; P = 0.002); however, there was an agreement for N22° (+0.14 D ± 1.16 D; P = 0.10). With respect to the identification of peripheral refraction patterns, examiners were able to identify relative peripheral hyperopia in most of the participants (77%). Conclusions: Peripheral refraction with P-ARC was comparable with open-field autorefractor at T22° and N22° eccentricities. Peripheral retinoscopy techniques can be another approache for estimating and identifying peripheral refraction and its patterns in a regular clinical setting. Translational Relevance: Retinoscope with P-ARC has high potential to guide and enable eye care practitioners to perform peripheral refraction and identify peripheral refraction patterns for effective myopia management.

A dual-modal retinal imaging system with adaptive optics.

An adaptive optics scanning laser ophthalmoscope (AO-SLO) is adapted to provide optical coherence tomography (OCT) imaging. The AO-SLO function is unchanged. The system uses the same light source, scanning optics, and adaptive optics in both imaging modes. The result is a dual-modal system that can acquire retinal images in both en face and cross-section planes at the single cell level. A new spectral shaping method is developed to reduce the large sidelobes in the coherence profile of the OCT imaging when a non-ideal source is used with a minimal introduction of noise. The technique uses a combination of two existing digital techniques. The thickness and position of the traditionally named inner segment/outer segment junction are measured from individual photoreceptors. In-vivo images of healthy and diseased human retinas are demonstrated.

Imaging system to assess objectively the optical density of the macular pigment in vivo.

This paper presents an optical system called MacPI, which implements a two-color reflectance technique in combination with various hardware and software tools to assess objectively the macular pigment (MP) optical density in vivo. The system consists of a bespoke optical design, a control architecture, driver electronics, a collection of image-processing techniques, and a graphical user interface. The deficiencies of the technique employed and the solutions implemented in the MacPI system to confront those inherent frailties are presented. An overview of the effective interpretation of the acquired data and the techniques employed by MacPI in the acquisition of that data is discussed. The result of a comparison trial with an alternative device is also presented. We suggest that appropriate design of the hardware and an efficient interpretation of the acquired data should produce a system capable of consistent, accurate, and rapid measurements, while retaining the distinction of ease of use, portability, comfort for the subject, and a design that is economic to produce. Its versatility should allow both for a clinical screening application and for further investigation and establishment of the physiological role of the MP in a laboratory-based environment.

Comparative intrinsic optical signal imaging of wild-type and mutant mouse retinas.

Functional measurement is important for retinal study and disease diagnosis. Transient intrinsic optical signal (IOS) response, tightly correlated with functional stimulation, has been previously detected in normal retinas. In this paper, comparative IOS imaging of wild-type (WT) and rod-degenerated mutant mouse retinas is reported. Both 2-month and 1-year-old mice were measured. In 2-month-old mutant mice, time course and peak value of the stimulus-evoked IOS were significantly delayed (relative to stimulus onset) and reduced, respectively, compared to age matched WT mice. In 1-year-old mutant mice, stimulus-evoked IOS was totally absent. However, enhanced spontaneous IOS responses, which might reflect inner neural remodeling in diseased retina, were observed in both 2-month and 1-year-old mutant retinas. Our experiments demonstrate the potential of using IOS imaging for noninvasive and high resolution identification of disease-associated retinal dysfunctions. Moreover, high spatiotemporal resolution IOS imaging may also lead to advanced understanding of disease-associated neural remodeling in the retina.

Angiography of the retina and the choroid with phase-resolved OCT using interval-optimized backstitched B-scans.

In conventional phase-resolved OCT blood flow is detected from phase changes between successive A-scans. Especially in high-speed OCT systems this results in a short evaluation time interval. This method is therefore often unable to visualize complete vascular networks since low flow velocities cause insufficient phase changes. This problem was solved by comparing B-scans instead of successive A-scans to enlarge the time interval. In this paper a detailed phase-noise analysis of our OCT system is presented in order to calculate the optimal time intervals for visualization of the vasculature of the human retina and choroid. High-resolution images of the vasculature of a healthy volunteer taken with various time intervals are presented to confirm this analysis. The imaging was performed with a backstitched B-scan in which pairs of small repeated B-scans are stitched together to independently control the time interval and the imaged lateral field size. A time interval of ≥ 2.5 ms was found effective to image the retinal vasculature down to the capillary level. The higher flow velocities of the choroid allowed a time interval of 0.64 ms to reveal its dense vasculature. Finally we analyzed depth-resolved histograms of volumetric phase-difference data to assess changes in amount of blood flow with depth. This analysis indicated different flow regimes in the retina and the choroid.

Three-dimensional retinal and choroidal capillary imaging by power Doppler optical coherence angiography with adaptive optics.

Retinal and choroidal vascular imaging is a key to the better understanding and diagnosis of eye diseases. To achieve comprehensive three-dimensional capillary imaging, we used an enhanced vascular imaging technique, so called adaptive optics optical coherence angiography (AO-OCA). AO-OCA enables in vivo high-resolution and high-contrast micro-vascular imaging by detecting Doppler frequency shifts. Using this technique, the retinal and choroidal vasculatures of healthy subjects were imaged. The results show that both intensity and Doppler power images have sufficient contrast to discriminate almost all vasculatures from the static tissue. However, the choriocapillaris, pre-arterioles, and post-venules in the Sattler layer were more contrasted by the Doppler technique. In conclusion, AO-OCA enables three-dimensional capillary imaging, and is especially useful for the detection of the choriocapillaris and choroidal capillary network.

Spectral-domain OCT with dual illumination and interlaced detection for simultaneous anterior segment and retina imaging.

We present Fourier-domain/spectral-domain optical coherence tomography (FD/SD-OCT) using a single spectrometer with dual illumination and interlaced detection at 830 nm, which can provide anterior segment and retinal tomograms simultaneously. Two orthogonal polarization components were used so that both parallel and focused beams could simultaneously be made incident on the eye. This configuration with a polarization-separated sample arm enables us to acquire images from the anterior segment and retina effectively with minimum loss of sample information. In the detector arm, a single spectrometer is illuminated via an ultrafast optical switch for interlaced detection. A graphical user interface (GUI) was built to control the optical switch for imaging the anterior segment and retina either simultaneously or individually. In addition, we implemented an off-pivot complex conjugate removal technique to double the imaging depth for anterior segment imaging. The axial resolution of our FD/SD-OCT system was measured to be ~6.7 µm in air, which corresponds to 4.9 µm in tissue (n = 1.35). The sensitivity was approximately 90 dB for both anterior segment and retina imaging when the acquisition speed was 35,000 A-scans per second and the depth position was near 120 µm from the zero-depth location. Finally, we demonstrated the feasibility of our system for simultaneous in vivo imaging of both the anterior segment and retina of a healthy human volunteer.

Repeatability and agreement of ARK-30 autorefraction after cataract surgery.

BACKGROUND: To evaluate the intra-test variability of ARK-30 handheld autorefractor and the agreement with subjective refraction and retinoscopy after uneventful cataract surgery. DESIGN: Prospective and non-randomized study that included 6 visits by patients undergoing uneventful cataract surgery at IOBA (Instituto de Oftalmobiología Aplicada) Eye Institute (University of Valladolid). PARTICIPANTS: The mean age of the 79 patients was 66.5years (range 23-90years). For the 124 eyes, the mean spherical equivalent of the sample at baseline visit was -3.59±6.28D (range -21.00D to +4.44D). METHODS: Automated refraction was performed on follow-up visits 1day and weekly for 4weeks. Retinoscopy and subjective refraction were conducted at the Week 4 follow up. MAIN OUTCOME MEASURES: Automated refraction. RESULTS: Sphere, cylinder and mean spherical equivalent, J(0) and J(45) coefficient variabilities were low in all visits. Standard deviations and the limits of agreement were smallest for the last visit. Subjective refraction sphere and cylinder values were more positive than autorefraction by 0.12±0.53D (P=0.031) and 0.23±0.42D (P<0.001), respectively. Comparison between autorefraction and retinoscopy showed a similar trend with the sphere and cylinder differences, 0.32±0.77D and 0.38±0.43D (P<0.05), respectively. CONCLUSIONS: The ARK-30 is sufficiently accurate and repeatable for automated refraction after uneventful cataract surgery. This instrument may be useful for monitoring refractive outcome in these patients.

[Letter from a reader]. / Leserbrief.

OBJECTIVE: Whether the treatment of benign ampullary tumors should be performed as transduodenal surgical excision or endoscopic ampullectomy depends on the size and spread of the tumor. In this videopaper we report technical hints on the surgical resection. INDICATIONS: Surgical resection is indicated for benign ampullary lesions if endoscopic resection is not possible. In addition, local resection can be performed in cases with high risk of malignancy or in a palliative intention. PROCEDURE: The duodenum is mobilized by the Kocher maneuver. It is recommendable to perform a cholecystectomy to introduce a flexible catheter antegrade into the common bile duct through the cystic duct for identification of the papilla of Vater by digital palpation. An anterolateral oblique duodenotomy is made and thereby the tumor of the papilla is exposed, followed by a submucosal injection of epinephrine to elevate the tumor. Afterwards a 5-10 mm margin is scored circumferentially in the mucosa around the adenoma. The extent of the excision is based on the preoperative and intraoperative assessment; a submucosal or full thickness (for transmural lesions) excision can be performed. After submucosal excision the mucosa of the ampulla is approximated to the mucosa of the duodenum. In cases with full thickness ampullectomy the borders of the pancreatic and bile duct are approximated and then the entire complex is sutured to the full wall of the duodenum. Furthermore in some cases with extensive resection a separate reconstruction of the pancreatic and bile duct may be required. A terminal assessment of the ductal patency is imperative. The duodenectomy is closed and a paraduodenal drain is placed. CONCLUSION: Transduodenal resection of periampullary tumors can be technically demanding, but provides a stage-adapted treatment modality for benign and premalignant lesions of the papilla of Vater.

[Use of Plusoptix as a screening method for refractive ambliopia]. / Folosirea plusoptix ca metoda de screening a ambliopiei refractive.

PURPOSE: Highlighting the differences in the objective refraction using the Plusoptix AO9 comparing them with the refraction performed with TOPCON KR-8900 autorefractor. METHODS: Prospective study for 3 months held in the Ophthalmology Clinic in Iasi, Hospital Sf. Spiridon on a total of 39 children (21 girls and 18 boys) with mean age of 10.61 +/- 5.67 years. Clinical parameters: sex, age, objective refraction obtained with Plusoptix and with autorefractor corrected visual acuity (with different methods depending on each patient age), ortoptic examination (strabic deviation, binocular vision), the presence of symetry/asymetry while measuring with Plusoptix. The results were statistically processed by F-TEST calculating the correlation coefficient, standard deviation, significance level (using the spherical equivalent of the obtained values). RESULTS: Age limits of the studied cases ranged between 2-23 years. Visual acuity of children who had cooperate was between 0.2-1 with correction, achieving best values on right eye than left eye. 8 cases (20.51%) had large differences between measurements made with Plusoptix and autorefractor, half of that (4 cases) had strabismus. Three of these cases were with small hypermetropia and one with small myopia (Plusoptix shows a lower value). In 2 cases occurred higher differences (about 2-2,5D) between the 2 measurements, in patients with average hypermetropia. Plusoptix refraction was not possible at high hypermetropia or high myopia. CONCLUSIONS: This type of determining objective refraction using Plusoptix is a useful method of screening for discovery of refractive errors that can cause refractive amblyopia in young children and in those cases with a difficult collaboration. Because there are differences betweeti this 2 methods, for children with refractive errors are recommended further exploration to determine the appropriate optical correction. Plusoptix is a limited method because it cannot detect the exact values in those cases with high hypermetropia or high myopia.

The Gimbalscope - A novel smartphone-assisted retinoscopy technique.

The authors describe a novel technique of performing retinoscopy assisted with a smartphone (gimbalscope). We found this technique of digital retinoscopy to be useful for demonstrating and documenting retinoscopic reflexes and in addition as an easy teaching tool. This technical report explains the assembly of our smartphone-assisted retinoscope and provides examples of the range of normal and abnormal reflexes that can be captured.

Scanning ophthalmoscope retinal image registration using one-dimensional deformation fields.

We present a new, robust and automated method for registering sequences of images acquired from scanning ophthalmoscopes. The method uses a multi-scale B-spline representation of the deformation field to map images to each other and an hierarchical optimization method. We applied the method to video sequences acquired from different parts of the retina. In all cases, the registration was successful, even in the presence of large distortions from microsaccades, and the resulting deformation fields describe the fixational motion of the eye. The registration reveals examples of dynamic photoreceptor behaviour in the sequences.