Light conditions influence optic nerve OCT angiography parameter in healthy subjects with neutral pupils.

Optical coherence tomography angiography measurements are influenced by a range of environmental factors as blood pressure and physical fitness. The present study aimed to evaluate the effects of light and dark exposure in eyes with neutral and mydriatic pupils on vessel density in the macular and optic nerve head regions, as measured using optical coherence tomography angiography (OCTA). 55 eyes of 55 healthy volunteers (28 patients with neutral pupils; 27.18 ± 4.33 years) were examined using a high-speed and high-resolution spectral-domain OCT XR Avanti system with a split-spectrum amplitude de-correlation angiography algorithm. OCTA imaging was performed after dark adaptation and after exposure to light. The vessel density data of the superficial and deep retinal macular and optic nerve head region OCT-angiogram were analyzed for these two light conditions. Through Bonferroni correction for multiple testing, the p- value was adapted from 0.05 to 0.017. In eyes with neutral pupils, a significant increase was found in the capillary region of the optic nerve head region (p = 0.002), comparing dark- and light-adaptation. In the macular region of eyes with neutral (p = 0.718) and mydriatic pupils (p = 0.043), no significant differences were observed, as were any in the optic nerve head region of the mydriatic eyes (p = 0.797). This observation suggests that light conditions could be a possible factor influencing OCTA measurements. After dark exposure, vessel density data were significantly different between eyes with neutral and mydriatic pupils (nerve head region: p < 0.0001, superficial macula: p < 0.0001, deep macula: p = 0.0025). These data warn for the effect of mydriatic drops on vessel density measurements.

[FIDUSweb version 2.0 : An electronic platform to establish a cooperative university eye network]. / FIDUSweb in der Version 2.0 : Möglichkeiten einer elektronischen Plattform zur Etablierung eines kooperativen, universitären Augennetzwerks.

BACKGROUND: Due to the increasing digitalization in ophthalmology, increasingly more documentation and diagnostic data are becoming electronically available. In order to improve patient care beyond sectoral boundaries, electronic cooperation portals were introduced in Münster and Homburg, which serve the networking with ophthalmologists in private practice. METHOD: This article reports on the implementation of an electronic cooperation portal at the University Eye Hospitals in Münster and Homburg in 2015 and 2016. RESULTS: The FIDUSweb represents a data protection-compliant cooperation portal that can be easily set up. By implementing it as a web portal all terminal equipment and also electronic patient files can be networked. Particularly important functions are the transmission of medical reports in real time, appointment booking functions, the transmission of imaging data and shared treatment documentation. CONCLUSION: Cross-sectoral care can greatly benefit from the use of the FIDUSweb, especially in digital and multimodal ophthalmology.

Impact of integrated multiple image averaging on OCT angiography image quality and quantitative parameters.

PURPOSE: Multiple image averaging (MIA) is a new approach to improve OCT angiography (OCTA) imaging. The aim of this work was to analyze the impact of MIA on image quality and quantitative OCTA parameters. METHODS: Twenty eyes from 20 healthy volunteers (55.65 ± 14.8 years) were prospectively enrolled. Imaging was performed using two commercially available OCTA devices (Canon OCT HS-100, Optovue AngioVue) using a uniform imaging protocol. Each participant had two single scans of the macula (3 × 3mm, Canon and Optovue) as well as five continuous single scan imaging procedures (3 × 3mm each) using the Canon device. Three out of five of these images with highest quality were manually chosen and then automatically processed by the Canon device using MIA. The superficial retinal plexus of the single scans and of MIA images was analyzed with regard to the device' own image quality scores (IQS), peak signal-to-noise ratio (PSNR), the size of the foveolar avascular zone (FAZ), and vessel density (VD). Image acquisition times were recorded. Parameters were compared between the devices and the different imaging protocols. RESULTS: Average acquisition time was significantly higher for the MIA compared with the single measurements (29.09 ± 10.19 seconds (s) (MIA) vs. 5.56 ± 2.17 s (Canon single scan) vs. 20.28 ± 6.81 s (Optovue) (p < 0.001)). IQS showed no significant differences between the devices and between the recording protocols. PSNR was 12.38 ± 0.20 (Canon single scan), 13.01 ± 0.36 (Canon MIA), and 14.34 ± 0.60 (Optovue) (p < 0.001 between the groups). Mean FAZ area in Canon single scans was 0.29 ± 0.06 mm2, 0.27 ± 0.07 mm2 using MIA, and 0.27 ± 0.08 mm2 using the Optovue device. There was no significant difference between mean FAZ measurements before and after averaging (Canon single scan vs. MIA, p = 0.168). VD of the parafoveal area using MIA was significantly lower compared with both single scans (p < 0.001). CONCLUSIONS: MIA can improve PSNR, but it also reduces imaging speed and significantly affects VD measurements. Therefore, when comparing OCTA data, the use of uniform imaging protocols is required.

Automated OCT angiography image quality assessment using a deep learning algorithm.

PURPOSE: To expedite and to standardize the process of image quality assessment in optical coherence tomography angiography (OCTA) using a specialized deep learning algorithm (DLA). METHODS: Two hundred randomly chosen en-face macular OCTA images of the central 3 × 3 mm2 superficial vascular plexus were evaluated retrospectively by an OCTA experienced reader. Images were defined either as sufficient (group 1, n = 100) or insufficient image quality (group 2, n = 100) based on Motion Artifact Score (MAS) and Segmentation Accuracy Score (SAS). Subsequently, a pre-trained multi-layer deep convolutional neural network (DCNN) was trained and validated with 160 of these en-face OCTA scans (group 1: 80; group 2: 80). Training accuracy, validation accuracy, and cross-entropy were computed. The DLA was tested in detecting 40 untrained OCTA images (group 1: 20; group 2: 20). An insufficient image quality probability score (IPS) and a sufficient image quality probability score (SPS) were calculated. RESULTS: Training accuracy was 97%, validation accuracy 100%, and cross entropy 0.12. A total of 90% (18/20) of the OCTA images with insufficient image quality and 90% (18/20) with sufficient image quality were correctly classified by the DLA. Mean IPS was 0.88 ± 0.21, and mean SPS was 0.84 ± 0.19. Discrimination between both groups was highly significant (p < 0.001). Sensitivity of the DLA was 90.0%, specificity 90.0%, and accuracy 90.0%. Coefficients of variation were 0.96 ± 1.9% (insufficient quality) and 1.14 ± 1.6% (sufficient quality). CONCLUSIONS: Deep learning (DL) appears to be a potential approach to automatically distinguish between sufficient and insufficient OCTA image quality. DL may contribute to establish image quality standards in this recent imaging modality.

[Optical coherence tomography angiography: Value for glaucoma diagnostics]. / Optische Kohärenztomographie-Angiographie: Stellenwert in der Glaukomdiagnostik.

BACKGROUND: Optical coherence tomography angiography (OCTA) is a novel noninvasive method which enables a quantitative evaluation of retinal and optic nerve head (ONH) perfusion. In this article, we discuss the principles of the application of OCTA and give a summary of the knowledge gained by using this method in glaucoma patients. METHODS: This article is based on a selective literature search and the analysis of own data. RESULTS: Quantitative OCTA parameters have a good reproducibility in glaucoma patients. Glaucoma patients show a reduced flow density (FD) in the ONH and in the area of the macula compared with a healthy control group. The FD parameters show a good diagnostic discriminatory power but are not superior to the structural parameters used in routine diagnostics. The reduced FD measured using OCTA correlates with the extent of functional and structural glaucoma damage. CONCLUSION: The OCTA is noninvasive, fast and reproducible. Initial results from studies on glaucoma patients show the high diagnostic potential of this method. The OCTA could become a part of clinical glaucoma management in the future.

[Foveal avascular zone and OCT angiography. An overview of current knowledge]. / Foveale avaskuläre Zone und OCT-Angiographie. Eine Übersicht aktueller Erkenntnisse.

BACKGROUND: The foveal avascular zone (FAZ) has often been analyzed under different aspects in the last decades, mainly by fluorescence angiography (FA); however, the novel technology of optical coherence tomography angiography (OCTA) enables a non-invasive examination, visualization and quantitative analysis of the FAZ, which has recently led to many new findings, especially in a multidisciplinary manner. This article provides an overview of the investigation of the FAZ using OCTA and the new findings that have been obtained using OCTA in recent years. METHODS: This article is based on a comprehensive literature review. RESULTS: In many studies a good reproducibility and repeatability of the FAZ measurements by OCTA could be proven, also by comparing different OCTA devices. In patients with ocular pathologies and systemic diseases, e. g. after retinal vein occlusion or retinal surgery and in patients with diabetes mellitus without diabetic retinopathy, differences to healthy control groups and correlations to visual function could be shown. Moreover, in patients with neurological diseases, such as Alzheimer's dementia, changes of the FAZ could be identified. CONCLUSION: The OCTA is a non-invasive technology, which enables a reliable visualization and reproducible quantification of the FAZ. The size of the FAZ seems to be altered in different retinal and systemic diseases, which also may correlate with visual function; however, long-term studies evaluating the diagnostic value of these changes in the course of the disease are currently lacking.

Prevalences of segmentation errors and motion artifacts in OCT-angiography differ among retinal diseases.

PURPOSE: To assess the prevalences of segmentation errors and motion artifacts in optical coherence tomography angiography (OCT-A) in different retinal diseases METHODS: In a retrospective analysis, multimodal retinal imaging including OCT-A was performed in one eye of 57 healthy controls (50.96 ± 22.4 years) and 149 patients (66.42 ± 14.1 years) affected by different chorioretinal diseases: early/intermediate age-related macular degeneration (AMD; n = 26), neovascular AMD (nAMD; n = 22), geographic atrophy due to AMD (GA; n = 6), glaucoma (n = 28), central serous chorioretinopathy (CSC; n = 14), epiretinal membrane (EM; n = 26), retinal vein occlusion (RVO; n = 11), and retinitis pigmentosa (RP; n = 16). Central 3 × 3 mm2 OCT-A imaging was performed with active eye-tracking (AngioVue, Optovue). Best-corrected visual acuity (BCVA) and signal strength index (SSI) were recorded. Images were independently evaluated by two graders using the OCT-A motion artifact score (MAS; scores I-IV) as well as a newly introduced segmentation accuracy score (SAS; score I-IIB). RESULTS: Mean SSI was 63.67 ± 9.2 showing a negative correlation with increasing age (rSp = - 0.42, p < 0.001, n = 206). In the healthy cohort, mean MAS was 1.45 ± 0.8 and segmentation was accurate (SAS I) in all eyes. In eyes with retinal pathologies, mean MAS was 2.1 ± 0.9 (p < 0.001). Lowest MAS was observed in GA (2.67 ± 0.5) and RVO (2.45 ± 1.1). Compared to an accurate segmentation in 100% in healthy subjects, 34.2% (n = 51) of all patients showed highest segmentation quality (p < 0.001). 63.8% showed segmentation errors in more than 5% of all single b-scans in one (SAS IIA, n = 58) or at least two (SAS IIB, n = 40) segmentation boundaries. Highest percentages of inaccurate segmentation (SAS IIA or IIB) were observed in the nAMD group (90.1%). The inner plexiform layer was the segmentation boundary most prone to inaccurate segmentation in all pathologies compared to the inner limiting membrane (ILM) and retinal pigment epithelium (RPE) segmentation layer. Incorrect ILM segmentation was only seen in patients with EM. CONCLUSIONS: Prior to both qualitative and quantitative analysis, OCT-A images must be carefully reviewed as motion artifacts and segmentation errors in current OCT-A technology are frequent particularly in pathologically altered maculae.

[Corneal densitometry : Value for keratoconus diagnostics]. / Korneale Densitometrie : Stellenwert in der Keratokonusdiagnostik.

BACKGROUND: Corneal densitometry, based on the Scheimpflug principle, is a useful noninvasive tool for quantitative evaluation of the optical quality of the cornea. It enables us to evaluate corneal transparency in the different corneal layers and different annuli. In this article, we discuss the basis of application of corneal densitometry measurements and summarize findings in patients with keratoconus. METHODS: This article is based on a selective literature review and analysis of own data. RESULTS: Patients with keratoconus have significant higher corneal densitometry values compared to healthy controls. Densitometry values also correlate with the extent of the disease. In the first months after corneal cross-linking (CXL), haze formation occurs and leads to a decrease in corneal transparency, thus densitometry peaks. Long-term analysis of densitometric data have shown that corneal transparency then starts to decrease after 3 to 6 months, and improves further with time. At 24 to 36 months after CXL, corneal transparency levels might achieve physiological values. CONCLUSION: Corneal transparency is reduced in patients with keratoconus. In the first months after CXL, haze formation and a reduction in corneal transparency can be observed, which subsequently improve with time.

[Spontaneous intraocular hemorrhage under oral anticoagulation : Apixaban in comparison to phenprocoumon]. / Spontane intraokulare Blutungen unter oraler Antikoagulation : Apixaban im Vergleich zu Phenprocoumon.

BACKGROUND: To determine and compare the frequency of intraocular hemorrhage in patients who underwent oral anticoagulation with apixaban or phenprocoumon. METHODS: A retrospective analysis of patients under oral anticoagulant medication (apixaban or phenprocoumon) seen between January 2015 and June 2015 at the department of ophthalmology, University of Muenster Medical Center was performed. Vitreal or retinal hemorrhage in addition to clinical information including age, gender, best corrected visual acuity, concomitant diseases, concomitant medication and therapy were obtained. Bleeding frequency in both groups was compared using Fisher's exact test. RESULTS: A total of 172 patients were included with a mean age = 74.0 ± 10.6 years, 57.0% (n = 98) male and 43.0% (n = 74) female. In the phenprocoumon group 147 patients (3.4%, n = 5) developed a retinal or vitreal hemorrhage. In the apxiban group 25 patients (36%, n = 9) developed a retinal or vitreal hemorrhage. There was a significant correlation between the group and bleeding risk (p < 0.001). CONCLUSION: There was a significant correlation between medication (apixaban vs. phenprocoumon) and bleeding risk in this study population. Further studies with more patients especially in patients with a high risk of hemorhage, age-related macular degeneration (AMD) and proliferative diabetic retinopathy are needed.

[Flow density measurements using optical coherence tomography angiography : Impact of age and gender]. / Messung der Flussdichte mittels OCT-Angiographie : Einfluss von Alter und Geschlecht.

BACKGROUND: This article presents the normative data for flow density measured using optical coherence tomography (OCT) angiography and the impact of age and gender is evaluated. METHODS: In this study 58 eyes from 58 healthy volunteers with no history of any ocular disease or ocular surgery were included. The OCT angiography imaging was performed using the RTVue XR Avanti with the AngioVue (Optovue, Fremont, CA). The macula was imaged using a 3 × 3 mm scan, and the flow density data in the superficial retinal OCT angiogram and deep retinal OCT angiogram were extracted and analyzed. The groups were compared using the Mann-Whitney U­test and the degree of correlation between two variables was expressed as the Spearman's correlation coefficient (rSp.) RESULTS: The mean subject age was 38.3 ± 14.6 years. The flow density (whole en face) in the deep retinal OCT angiogram was significantly higher compared to the flow density in the superficial retinal OCT angiogram (p < 0.001). There was no significant difference in the mean flow density in superficial and deep OCT angiograms of the macula between males (n = 27) and females (n = 31). There was a significant correlation between the flow density in the deep retinal OCT angiogram and age (rSp. = -0.41, p = 0.001). CONCLUSION: Whereas gender has no impact on the flow density measured using OCT angiography, there was a significant correlation between the flow density in the deep retinal OCT angiogram and age.

[Glaucoma Drainage Devices: Tube versus Trabeculectomy Study]. / Glaukomdrainageimplantate und ihre Bedeutung: Tube-versus-Trabekulektomie-Studie.

While trabeculectomy with mitomycin C has previously been the gold standard in penetrating glaucoma surgery, glaucoma drainage implants used early within glaucoma surgery were examined in the course of the tube versus trabeculectomy (TVT) study. Glaucoma drainage implants are now being used earlier, as materials are tissue-compatible and surgery has been improved. While in the past, the use of such implants was often carried out after multiple preoperations, implants are now being used at an earlier stage. Glaucoma drainage implants are typically still used in the pseudophakic eye, where 1-2 glaucoma preoperations (e.g. trabeculectomy) have already been performed.

[Choroidal neovascularisation in a patient with choroidal osteoma visualized by OCT angiography]. / OCT-angiographische Darstellung einer choroidalen Neovaskularisation infolge eines Aderhautosteoms.

We present the case of a 38-year-old Asian patient who reported vision loss of her left eye since 4 weeks. The funduscopy showed a choroidal tumor in the papillomacular bundle, which could be identified as a choroidal osteoma with secondary choroidal neovascularization (CNV). OCT angiography (OCT-A) detected abnormal flow in the choriocapillaris; the osteoma showed no flow in the OCT angiogram of the choroid level. Therefore, OCT-A can be a helpful adjuvant for diagnosis of CNV secondary to choroidal osteoma.

[Contact lens-associated Paecilomyces lilacinus keratitis]. / Kontaktlinsenassoziierte Paecilomyces-lilacinus-Keratitis.

We present the case of a 23-year-old otherwise healthy female patient with contact lens-associated Paecilomyces lilacinus keratitis. The clinical findings stabilized after initial local antimycotic and antibacterial treatment; however, in the further course of local therapy an extensive relapse occurred which required treatment by perforating keratoplasty à chaud due to a penetrating corneal ulcer. The patient responded well to subsequent treatment with systemic and local antimycotic medication. After a few months HLA-matched keratoplasty was performed. During the follow-up time of 14 months there were no signs of recurrence of the infection.

Long-Term Outcomes of External Dacryocystorhinostomy in the Age of Transcanalicular Microendoscopic Techniques.

Purpose. This study aimed to evaluate long-term results of external dacryocystorhinostomy (DCR) at a tertiary eye care center specializing in lacrimal duct surgery in Germany. Methods. The medical records of 1010 patients with acquired nasolacrimal duct obstruction (NLDO), who had undergone lacrimal duct surgery at a tertiary eye care center, were reviewed. Only adult patients who had undergone external DCR were included. The evaluation included the following parameters: age, gender, duration of symptoms, patient satisfaction, previous dacryocystitis, complication rates, and surgical outcome. Results. 154 eyes of 146 patients (14.5%) could be included in the study. The average age was 64.1 ± 29.7 years. 66.4% of patients were females and 33.6% were males. Acute or chronic dacryocystitis was found in 81 patients (55.5%). Overall, 82.8% of patients had full resolution of symptoms. The success rate of external DCR for patients with previous episodes of dacryocystitis was 82.7% compared to 83.4% for patients without dacryocystitis in their medical history. Conclusion. In cases in which transcanalicular microendoscopic techniques are contraindicated (e.g., after dacryocystitis) or in complex cases where microendoscopic procedures have failed (revision surgery), external DCR is still the surgical treatment of choice with very good postoperative success.

[Vitrectomy for retinal proliferation in childhood following hemolytic uremic syndrome]. / Vitrektomie bei retinaler Proliferation im Kindesalter nach hämolytisch-urämischem Syndrom.

The formation of retinal membranes can occur due to a variety of reasons but they are most commonly idiopathic due to the aging process. In addition, epiretinal and subretinal membranes can be formed after severe infections. The present case description shows the appearance of a retinal membrane after hemolytic uremic syndrome caused by Shiga toxin positive E. coli. The question arose whether the patient would benefit from vitrectomy with membrane peeling because of the presence of both epiretinal and subretinal gliotic changes. After the operation on the more severely affected right eye a morphological improvement could be achieved so that an operation on the left eye was also recommended. Judging by the course of this case vitrectomy with membrane peeling seems to be a useful instrument even for the simultaneous presence of subretinal and epiretinal membranes.

[Ease of handling of first and second generation rebound tonometers]. / Handhabung von Reboundselbsttonometern der ersten und zweiten Generation.

PURPOSE: To evaluate the ease of handling of two rebound tonometers, which are designed for self-measurement of intraocular pressure (IOP) in a clinical setting by untrained patients. METHODS: After self-measurement of the IOP with the rebound tonometers iCare ONE and iCare HOME, participants were asked to complete a questionnaire containing different subitems concerning ease of operation using a visual analog scale (1 = very good to 5 = very poor). Moreover, the feasibility and duration of measurement were tested. RESULTS: A total of 147 subjects participated in this study. The mean score for general handling ability was 2.79 ± 1.01 for the iCare ONE and 1.85 ± 0.87 for the iCare HOME (p < 0.001). The evaluation of the subitems sense of safety (iCare ONE: 2.71 ± 1.03 and iCare HOME: 1.87 ± 0.81, p < 0.001) and comfort of measurement (iCare ONE: 2.07 ± 1.01 and iCare HOME: 1.66 ± 0.72, p < 0.001) also showed a significant discrepancy between the two tonometers. Participants needed significantly less time for a single valid measurement when using the iCare HOME tonometer (mean 66.14 ± 61.54 s) compared to the iCare ONE tonometer (mean 81.54 ± 69.51 s, p < 0.001). CONCLUSIONS: A better handling of the iCare HOME rebound tonometer in comparison to the iCare ONE tonometer can be deduced on the basis of the subjective assessments of patients and the shorter duration of measurements. Moreover, the iCare HOME received a significantly better evaluation for all subitems. The accuracy of measurements using the iCare HOME still needs to be clarified.

[Traumatic Lacrimal Duct Stenosis: Demographics and Success Rate of Surgical Procedures for Secondary Treatment]. / Traumatische Tränenwegsstenosen: Epidemiologie und Erfolgsraten nach sekundärer operativer Intervention.

BACKGROUND: Traumatic lacrimal duct stenosis can be the result of sharp trauma of the eyelid, indirect trauma or surgery in the nasoorbital region, as well as burns, chemotherapy and radiation of the facial region. The aim of the study is to present the demographics, patient satisfaction, and course of different surgical procedures for secondary treatment of traumatic lacrimal duct stenosis. METHODS: We retrospectively reviewed the medical records of 50 patients who required surgery for traumatic lacrimal duct stenosis from 2009 to 2011 at the University Eye Hospital in Muenster. The evaluation included the following criteria: age, sex, duration of symptoms, complication rate and the rate of recurrence. We systematically evaluated the medical data and asked the patients about the recent symptoms via telephone questionnaire. RESULTS: 60 eyes of 50 patients were included (18 women; 32 men; age: 51.8 ± 17.1 years); 34 eyes (56.7 %) had already had operations of the lacrimal system. The success rate was 58.1 %. The mean postoperative follow-up was 52.3 ± 10.7 months. In 11 cases (18.3 %), a dakryocystorhinostomy (DCR) was necessary. CONCLUSION: Traumatic lacrimal stenosis is more common in men, and has a poorer prognosis than lacrimal duct stenosis from other causes.