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.

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.

[Spontaneous intraocular hemorrhage under oral anticoagulation : Apixaban in comparison to 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]

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 U‑test 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.

[Optical coherence tomography angiography: Value for glaucoma diagnostics]

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.

[Glaucoma Drainage Devices: Tube versus Trabeculectomy Study]

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.

[Contact lens-associated 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.

[Implementation of electronic health records at a tertiary care eye hospital]

BACKGROUND

Although electronic health records (EHR) were introduced into ophthalmology practices many years ago, paper-based medical records are still common in most tertiary care eye hospitals.

MATERIAL AND METHODS

We report on the implementation of an EHR system at the university eye hospital in Münster in the time period between January and December 2013.

RESULTS

Advantages of an EHR system in the setting of a university eye hospital include ubiquitous access to patient data, structurability as well as scientific interpretability. Data safety, personnel and financial investment and integration into existing hospital software systems represent the main challenges.

CONCLUSION

The EHR system will replace paper-based records in the future. In view of the high need for visualization and recording of medical findings, EHR software solutions seem promising particularly in ophthalmology.

[Traumatic Lacrimal Duct Stenosis: Demographics and Success Rate of Surgical Procedures for Secondary Treatment]

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.

[Ease of handling of first and second generation rebound tonometers]

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.

[Effect of Hypericin on the Function of the Neuroretina: An Electroretinographic Study]

BACKGROUND

Hypericin is an important component of the Saint John's wort (Hypericum perforatum). It is assumed to inhibit intracellular signalling cascades, which contribute to neoangiogenesis. The phototoxic effect of hypericin on the retina was investigated in human retinal pigment epithelium (RPE); hypericin induces oxidative stress and has also been described to be an inhibitor of Ca(2+) influx channel in cultured RPE cells. The aim of our study is to evaluate the effect of hypericine on the function of the neuroretina.

METHODS

Isolated bovine retinas were perfused with an oxygen saturated nutrient solution (1 mL/min). We exposed the retina to a flashlight of 6.3 mlx every 5 min. The electroretinogram (ERG) was recorded as a transretinal potential using Ag/AgCl electrodes. ERGs were monitored before, during and after hypericin exposure.

RESULTS

In three independent experiments we investigated the effect of hypericin on the amplitude of the b-wave. In our experiments we observed a significant reduction of the amplitude of the b-wave to 87.1 ± 3.5 % (p = 0.02). This reduction was in all our experiments partially reversible. After hypericin wash-out the b-wave amplitude did not recover completely and did not return to the initial value (91.0 ± 5.1 %; not significant). We did not observe a significant effect of hypericin on the implicit time of the b-wave.

CONCLUSION

This study shows for the first time that hypericin influences retinal signal transduction, suggesting that hypericin impairs not only the RPE, but also affects retinal signalling and function.

[Microsurgical Treatment of Canalicular Stenosis: Long-Term Follow-Up]

PURPOSE

Studies about the indication and the functional prognosis of microsurgical treatment of canalicular stenosis (CR) are rare. In this study we determined the cause, recurrence and success rates of CR and compared our results with the results in the literature.

METHODS

We retrospectively reviewed the medical records of 22 patients who required a microsurgical treatment of canalicular stenosis (CR) from 2009 to 2011. We systematically evaluated the medical data and asked the patients about the recent symptoms via telephone questionnaire.

RESULTS

22 patients were included (73 % women; 27 % men; age: 52.8 ± 19.9 years), 12 (55 %) patients had already had operations. The mean postoperative follow-up was 45 ± 9.2 months. The patients were followed for a minimum of 30 months. The success rate was 58 %.

CONCLUSION

In some cases like long localised canalicular stenosis and especially after traumatic lacerations of the lacrimal canaliculi, a microsurgical treatment of canalicular stenosis is required. The aim of this procedure is to restore the lacrimal mucosa continuity so that a spontaneous lacrimal drainage is possible. The success rate of CR in our study was 58 %.

[Successful treatment of Fusarium-associated keratitis with multiresistant pathogen and multimorbid patient]

A 75-year-old man (not a contact lens wearer) presented with Fusarium-associated hypopyon keratitis. After several weeks of empirical and subsequently targeted antimycotic treatment, no considerable improvement was observed. However, after sclerokeratoplasty (11.2 × 11.2 mm) combined with prolonged antimycotic therapy a good local result with relapse-free long-term follow-up was achieved.