Confocal Microscopy of Filtering Blebs after Trabeculectomy

Introduction: Filtration surgery is the most effective method of lowering intraocular pressure (IOP) in patients with insufficient medical control. It consists in facilitating the drainage of the intraocular fluid (IOF) from the anterior chamber to the subconjunctival space and subsequent lowering of IOP. The formation of filtration blebs (FB) and the processes of scarring occurring in the conjunctiva are of particular importance in glaucoma surgery. In many cases, the appearance of FB does not match the IOP values, and what causes the failure after trabeculectomy often remains unclear. Often, over time, there is a change in the structure of the FB, as fibrous tissue grows, which prevents the IOF drainage. Laser scanning in vivo confocal microscopy is a non-invasive study allowing the production of layered images at the microstructural level with high resolution of both the cornea and other structures of the anterior ocular surface. Aim: To evaluate the morphological structure and function of filtering blebs after trabeculectomy using in vivo confocal microscopy taking into account the type of implant and when the surgery was performed. Materials and methods: The study included 33 patients, 46 eyes with glaucoma. Twenty-six of the eyes had primary open-angle glaucoma (POAG), 18 eyes had pseudoexfoliative glaucoma and 2 eyes had juvenile glaucoma. All patients underwent trabeculectomy with fornix-based flap, and three of the eyes underwent retrabeculectomy. Mitomicyn C (MMC) was administered intraoperatively to all patients. The study of the filtering bleb was performed by in vivo confocal microscopy (CFM) (Heidelberg Retina Tomograph II (HRT II) /Rostock Cornea Module/ (Heidelberg Engineering GmbH, Heidelberg, Germany), the period from trabeculectomy and examination being from 1 year to 22 years. An Express implant was placed in 14 eyes, Ologen implant in 7 eyes, and 25 eyes had no implant placed. In the analysis of the morphological structure of the filtering blebs, three indicators were evaluated: the type of epithelium, the type of stroma, and blood vessels. Results: Statistical significance was established with regard to the function and morphological structure of the filtering bleb (p=0.009). Blebs with fine collagen mesh and dense collagen mesh demonstrate good function. In the case of blebs with insufficient function, those with a dense collagen network and hyper-reflective tissue predominated and there were no blebs with a fine collagen network, and in non-functioning blebs most common were those with a pronounced collagen network and hyper-reflective tissue. With regard to vascularization, we found that the functioning blebs in the shortest postoperative period were dominated by those with one blood vessel (stage 1) and there was no stage 3, with weak tortuosity, while in non-functioning blebs in the late postoperative period, there was moderate to severe vascularization and tortuosity (p=0.037), (p=0.043), (p=0.047), (p=0.021). The type of implant affects the tortuosity of the blood vessels of the filtering bleb (p=0.026). The blebs with Express implants show a slight tortuosity, followed by the blebs with Ologen implants. The highest percentage of highly kinked blood vessels occurred in blebs without an implant. Conclusions: In vivo confocal microscopy is an innovative method which allows visualization of the internal structure of the filtering blebs at a cellular level, giving us a new insight into the ongoing healing processes, premising the function of the filtering blebs after glaucoma surgery.

Microcatheter-Assisted Trabeculotomy Combined With Deep Sclerectomy and Trabeculectomy in Young to Middle-Aged Adults With Advanced Primary Open-Angle Glaucoma: 1-Year Result

Objective: We aimed to evaluate the safety and clinical efficacy of ab externo microcatheter-assisted trabeculotomy combined with deep sclerectomy and trabeculectomy (MATT-DS-Trab) in the surgical management of advanced primary open-angle glaucoma (POAG).Methods: According to the inclusion criteria, we retrospectively collected and analyzed 37 POAG cases in advanced stage who received MATT-DS-Trab. The intraocular pressure (IOP), best corrected visual acuity (BCVA), use of anti-glaucoma drugs, shape of the filtering bleb, size of the scleral lake, complications, and the surgical success rate were recorded.Results: The mean IOP was 37.50 ± 8.11 mmHg before the operation, while it depleted to 10.08 ± 2.01 and 11.43 ± 2.07 mmHg at 1 week and 12 months after the operation, respectively (both P < 0.001 compared to preoperative IOP). From none to two kinds of anti-glaucoma drugs were used 12 months after surgery on the patients, which were significantly reduced compared with that preoperatively (P < 0.001). An L-type filtering bleb was the main form at all time points after the operation. At 12 months following surgery, an F-type filtering bleb accounted for 5.41% and no E-type filtering bleb was recorded. The length and height of the scleral lake shrunk with time, but there was no statistical significance (P > 0.05). Also, there was no correlation between the size of the scleral pool and the IOP (P > 0.05). At 12 months after the operation, the complete success rates were 94.59, 83.78, and 72.97% according to standards A (≤18 mmHg), B (≤15 mmHg), and C (≤12 mmHg), respectively. Intraoperative complications were mainly anterior chamber hemorrhage, and no complications related to the filtration bleb were observed after the operation.Conclusion: Based on multichannel mechanisms, MATT-DS-Trab is able to effectively reduce IOP in advanced POAG patients, with few serious complications and a high success rate.

Hydrophilic Bile Acid, Ursodeoxycholic Acid Attenuates the Effect of TGF On Human Tenon Fibroblast

Excessive scarring of the filtering bleb was reported post-surgery and thus lead to failed trabeculectomy.

Results of filtering bleb investigation by thermography method after glaucoma surgery

Thermography is the method of noninvasive registration of visible image of own infrared radiation of the human body surface by special devices. The results of filtration bleb investigation, carried out by thermography method are presented in patients with open angle glaucoma in different terms after glaucoma surgery. Purpose. To execute an investigation of a filtration bleb in patients with open angle glaucoma in different terms after glaucoma surgery by method of thermography. Material and methods. 35 patients (35 eyes) with open angle glaucoma were examined after 1, 7 days, after 1-3-6 months after minimally invasive sinustrabeculectomy. Authors used thermal imaging Тesto 875-2i with SuperResolution technology and telephoto lens 9° x 7°. The bleb area and temperature were evaluated With IRSoft and Universal Desktop Ruler programmes. Intraocular pressure (corneal compensated) (IOPcc) was measured with Ocular Response Analyzer®, ORA. Investigation protocol included 2 groups. Group №1 - 15 patients (15 eyes) with moderate glaucoma. Group №2 – 20 patients (20 eyes) with advanced glaucoma. All patients went through glaucoma surgery, microinvasive sinustrabeculectomy. Management and recurrent examinations were carried out in 1 and 7 day after glaucoma surgery; then in 1, 3 and 6 months after surgery. Results. The IOP level was credibly lowered in all patients in all terms of management in comparison with the baseline IOP level. High statistical correlation was determined in patients of 1 group between IOPcc and the index of temperature difference (between filtering bleb and surrounding conjunctiva temperatures), correlation coefficient >0,7, in all management terms after surgery (in 1, 3, 6 months). In 2 group there was determined statistical correlation between IOPcc and index of temperature difference between filtering bleb and surrounding conjunctiva temperatures (Δ Тsc - Тfb) in 1 week, in 1 and 3 months after surgery. The same correlation coefficient was determined between filtering bleb temperature and Δ Тsc- Тfb in 6 months after surgery. Conclusion. Thermography is a safe and noninvasive method, that credibly detects temperature elevation in surgery zone, indicates IOP level raise and can predict starting of filtering bleb scarring. This method defines the necessity of needling procedure execution in different terms after surgery treatment and allows to control its effectiveness. Key words: open angle glaucoma, filtering bleb, scarring, thermography, corneal compensated intraocular pressure, Ocular Response Analyzer.

Activation of uveolymphatic outflow pathway after non-penetrating glaucoma surgery without filtering bleb: case reports

The authors propose a modified technique of non-penetrating filtering glaucoma surgery for primary open-angle glaucoma (POAG) to improve the uveoscleral outflow. The study enrolled 11 patients with POAG. A novel surgical technique included two steps. The first step was modified deep sclerectomy and cyclodyalysis with collagen implant placed into the supraciliary space. The second step (after 7–10 days) was YAG laser trabeculotomy. Surgical site and adjacent areas were examined by optical coherence tomography (OCT). After 6 months, mean IOP significantly reduced by 52% (from 30.0±10.3 mm Hg to 14.6±5.0 mm Hg, р=0.0004) while the number of IOP-lowering medications reduced by 79% (from 2.9±1.0 to 0.6±0.4, р=0.000001). The aqueous humor outflow occurred through conjunctival lymphatic vessels without filtering bleb formation, as illustrated by OCT. Postoperative complications were minor and easy-to-treat. Three case reports are discussed. Keywords: open-angle glaucoma, glaucoma surgery, conjunctival lymphatics, filtering bleb, non-penetrating glaucoma surgery, uveolymphatic outflow pathway. For citation: Kumar V., Abu Zaalan K.A., Frolov M.A. et al. Activation of uveolymphatic outflow pathway after non-penetrating glaucoma surgery without filtering bleb: case reports. Russian Journal of Clinical Ophthalmology. 2021;21(2):108–115. DOI: 10.32364/2311-7729-2021- 21-2-108-115.

Patient creates filtering bleb: hypotony following traumatic rupture of an old scleral incision for intracapsular cataract surgery

An 86-year-old woman presented with symptomatic hypotony on the left eye since a few weeks, blurry vision and a very sensitive eye. She had a history of bilateral intracapsular cataract extraction (ICCE) in 1982 and secondary intraocular lens implantation in 1988. The patient mentioned a fall on the left side of the head 6 months earlier. The diagnosis of a superior scleral fistula was made, confirmed by gonioscopy and anterior segment optical coherence tomography. Direct surgical repair of the fistula led to a favourable outcome. This case demonstrates the occurrence of symptomatic hypotony due to the traumatic creation of a scleral fistula with an inadvertent filtering bleb many years after ICCE, and the resolution of signs and symptoms after surgical repair. Conventional as well as contemporary modalities can be valuable in the assessment of such fistulae. Management depends on the clinical course and the mechanism and extent of fistulation.