Assessment of the Efficacy of Microinvasive Glaucoma Surgery Techniques using an Oculopression Stress Test. / Nicht invasiver Belastungstest zur Funktionsprüfung von mikroinvasiven Glaukomdrainage-Implantaten und Laserchirurgie.

BACKGROUND: Glaucoma is one of the most common causes of blindness worldwide. The only evidence-based treatment to slow down the progression of glaucoma is the reduction of intraocular pressure (IOP) using local medication or through surgery. During the last years, a large number of microinvasive glaucoma surgery techniques (MIGS) has been developed, in order to reduce the IOP in glaucoma patients safely and effectively. Until now, efficacy of MIGS has been assessed mainly according to the postoperative IOP and the number of medications used. Results from long-term studies are rare or not available in the majority of the cases. In order to better evaluate the functionality of MIGS, a new examination method has been developed with the help of a new oculopressor device. In this study the efficacy of different MIGS techniques will be examined using the new oculopressor. MATERIAL/METHODS: At first, glaucoma patients that had previously received a MIGS surgery (iStent inject, XEN Stent, ELT) were examined with the new oculopression test. Their results were compared with those of non-operated patients and healthy individuals. Overall, 38 healthy subjects (group 1), 10 non-operated patients (group 2), 19 patients after iStent inject implantation (group 3), 14 patients after XEN Stent implantation (group 4) and 5 patients after ELT (group 5) were examined. The new examination measures the IOP-reduction that occurs after oculopression and can be seen as an indirect measurement of the outflow facility of the eye. RESULTS: The IOP-reduction after oculopression differed among the study groups. Non-operated patients showed a significantly lower IOP-reduction compared to healthy individuals. Patients after iStent inject and XEN stent implantation showed a larger reduction of IOP after oculopression in relation to non-operated patients and their results approximated those of healthy individuals. These patients needed fewer medications postoperatively in relation to non-operated patients. Patients after ELT showed postoperatively a smaller reduction of IOP after oculopression compared to iStent inject and XEN stent patients. CONCLUSION: MIGS can increase the outflow facility of the eye in patients with glaucoma. Though ELT had the lowest impact on the aqueous outflow among the studied procedures in this study. The new test can help in the evaluation of current and further development of new MIGS in the future.

[Development of an Oculopressor to Evaluate the Efficiency of Glaucoma Drainage Devices]. / Entwicklung eines Okulopressors zur Evaluation der Funktionalität von Glaukomdrainage-Implantaten.

PURPOSE: Evaluation of the long-term efficiency of MIGS implants is still challenging, due to the lack of standardized clinical studies of stand-alone procedures. Moreover, the different mechanisms of the various glaucoma drainage devices are not adequately considered. The current study focusses on the development of a method for oculopression to evaluate the efficiency of glaucoma drainage devices. METHODS: Explanted porcine eyes were subjected to pressure or weight load using three oculopressors with different modi operandi. The time-dependent intraocular pressure was measured using an anterior chamber maintainer. The Honan Balloon exerts variable pressure onto the eye via an air bellows, whereas the Taylor oculopressor applies a defined weight loading on the eye. A novel oculopressor with a weight loading of 60 g was developed and manufactured by means of 3-D-printing. RESULTS: The intraocular pressure changes observed during the experiments were similar for all tested oculopression devices, varying only in the absolute pressure values. The Honan Balloon was not suitable for the intended purpose, due to poor standardisation of the applied pressure. Oculopression using a defined weight appeared more suitable. The Taylor oculopressor, however, created intraocular pressure values of up to 203.3 ± 38.4 mmHg, which precludes its use with glaucoma patients. On the basis of these data, the new oculopression device was used in a preliminary trial with healthy human subjects, thereby preparing its use in a clinical trial. CONCLUSIONS: Oculopression represents a potentially suitable tool to analyse the efficiency of glaucoma drainage devices. Commercially available oculopression devices are not directly applicable for this task. Difficult handling, high intraocular pressure, and lack of standardisation complicate the use for glaucoma patients. These difficulties were overcome with the newly designed oculopressor that facilitates a well defined increase in intraocular pressure. The device is currently being used in a clinical study to evaluate the efficiency of MIGS implants.

[Measurement of the Strength of Human Musculus Orbicularis Oculi Using Video Analysis]. / Messaufbau zur videoanalysebasierten Bestimmung der Lidschlusskraft des humanen Musculus orbicularis oculi.

Introduction Current methods to measure the of strength of the musculus orbicularis oculi are limited by high proneness to examiner error or by their complex and impracticable set-ups. Our aim was to develop a simple and practicable method to measure eye lid power via video analysis. Methods 50 healthy subjects were included. A deformable single use lid speculum was used. Forced maximum lid closure was recorded via a video slit lamp. Analysis of the video data was performed with open source tracking software. The maximum and minimum distances of the inserted lid speculum were detected. The rigidity and mechanical characteristics of the lid speculum were tested separately. In this way, lid power could be determined by analysis of the maximum compression of the lid speculum. To explore the impact of age and sex on eye lid power, Pearson's correlation coefficient was evaluated. ICC (intra class correlation) was analysed as a measure of reliability. Results In three repeated measurements in 9 subjects, an ICC of α = 0.91 was detected. With 50 healthy subjects, the range of lid power was 0.62 - 4.72 N. No correlation was found between the age of the subjects and eyelid power (Pearson's correlation coefficient = 0.054). A weak correlation was found between the sex of the subjects and eyelid power. For female subjects, the mean power was 1.82 N and for male subjects 2.58 N (Pearson's correlation coefficient = 0.428). Discussion A test series of 50 healthy subjects exhibited a wide range of lid power. The wide range makes it difficult to distinguish between pathological and normal eyelid power. The major application field of the method may therefore be in inner-individual measurements of known eyelid pathologies, such as paresis of the facial nerve or ocular myasthenia.

Non-invasive detection of corneal sub-basal nerve plexus changes in multiple myeloma patients by confocal laser scanning microscopy.

PURPOSE: Confocal laser scanning microscopy (CLSM) is a non-invasive technique for cellular in vivo imaging of the human cornea. CLSM screening was evaluated for early detection of corneal nerve morphology changes and neuropathogenic events in different stage multiple myeloma (MM) patients. As MM patients show disease as well as therapy-related neuropathological symptoms, CLSM potentially provides a tool for non-invasive early detection of neuropathogenic events. CLSM findings were compared with the severity of peripheral neuropathic (PNP) symptoms. METHODS: The study enrolled 25 MM patients in which bilateral ophthalmologic examination was performed including unilateral CLSM. Further peripheral nerve function was clinically evaluated using the conventional neuropathy symptom and neuropathy deficit scores (NDSs). RESULTS: In 18/25 MM patients, CLSM detected atypical morphological appearance of bulb-like enlarged nerve endings in the corneal sub-basal nerve plexus. These neuromas were only found in patients showing moderate to severe PNP, in patients with mild or lacking PNP neuromas were absent. CONCLUSIONS: CLSM provides a novel non-invasive diagnostic tool for identification of neuromas in cancer patients affected by therapy or disease-related neuropathologies, perspectival allowing early neuronal degenerative process detection and monitoring.

Hyaluronic Acid as an Alternative to Autologous Human Serum Eye Drops: Initial Clinical Results with High-Molecular-Weight Hyaluronic Acid Eye Drops.

INTRODUCTION: Autologous serum eye drops (ASED) are used in the treatment of most severe stages of dry eye. Once introduced, it is currently considered impossible to return to other lubricating eye drops or other commercially available therapeutic regimen. MATERIALS AND METHODS: In a randomized study, non-preserved high-molecular-weight hyaluronic acid eye drops were offered as an alternative to 11 patients using autologous serum treatment for at least 3 months. The control group (n = 5) continued their treatment with ASED. The verum group (n = 6) used very-high-molecular-weight hyaluronic eye drops (Comfort Shield®) instead of the ASED. RESULTS: From four of initially six patients in the verum group that finished the study, 2 (50%) preferred to stay with the very-high-molecular-weight hyaluronic acid eye drops beyond the trial period, the other two returned to the earlier therapy with ASED. The control group continued their treatment as before and finished the study after 8 weeks. CONCLUSION: For the first time, artificial eye drops, i.e., high-molecular-weight hyaluronic acid eye drops, offered an acceptable alternative to ASED. Some patients perceived these drops as even better than the patient's own serum. This is the first evidence that optimization of the molecular structure of hyaluronic acid can be used to create eye drops that are perceived to be better than other tested tear substitutes and even patients' own serum. This offers a new treatment perspective for patients with very severe dry eye disease.