Analysis of bleb morphology after trabeculectomy with Visante anterior segment optical coherence tomography

BACKGROUND: To describe the use of anterior segment optical coherence tomography (OCT) in imaging intrableb morphology after trabeculectomy. METHODS: 14 post-trabeculectomy eyes from 11 primary open angle glaucoma and 3 primary angle closure glaucoma subjects were studied. The blebs were classified with reference to slit lamp morphology and bleb function. They included diffuse filtering (n = 7), cystic (n = 2), encapsulated (n = 2) and flattened (n = 3) bleb types. One eye in each patient was imaged with the Visante anterior segment OCT. A vertical scan line of 10 mm consisting of 512 A-scans was positioned at the centre of the bleb. The images were then analysed by built-in software. Intrableb morphologies and structures, including bleb wall thickness, subconjunctival fluid collections, suprascleral fluid space, scleral flap thickness, intrableb intensity (low, medium or high) and the route under the scleral flap were characterised and measured. RESULTS: Diffuse filtering blebs were found by subconjunctival fluid collections. Suprascleral fluid space and the route under the scleral flap were identified in four of the seven cases. Cystic blebs were composed of a large hyporeflective space with multiloculated fluid collections covered by a thin layer of conjunctiva. Encapsulated blebs had a thick bleb wall with high reflectivity and an enclosed fluid filled space. Flattened blebs demonstrated high scleral reflectivity and no bleb elevation. CONCLUSIONS: Visante anterior segment OCT can be used for bleb imaging. The different patterns of intrableb morphology identified by OCT were related to slit lamp appearance and bleb function. This information may be useful to study the different surgical outcomes and the process of wound healing in trabeculectomised eyes.     

Imaging implanted keratoprostheses with anterior-segment optical coherence tomography and ultrasound biomicroscopy

PURPOSE: To describe the anterior ocular segment findings of eyes with implanted Boston type 1 keratoprostheses (KPro) in vivo by using anterior-segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM). METHODS: A retrospective, comparative study was made of patients with implanted KPros who were examined with AS-OCT (AC Cornea OCT) and UBM (OTI Scan 35-50 MHz Ultrasound). RESULTS: One pseudophakic and 1 aphakic eye were included in the study. Cross-sectional AS-OCT adequately imaged the components of the KPro (front plate with stem, back plate, and titanium ring), the corneal graft, and host cornea. The angles could be seen as open, filled with debris, or closed. Coronal AS-OCT showed en face views of each KPro part. Retrokeratoprosthetic membranes were depicted to be thick opacities covering the rear optical surface of the stem. UBM, on the other hand, imaged the KPro front plate as a muffin-shaped space at the apical center, with the corneal graft appearing wispy and the host cornea grainy. The back plate, titanium ring, and angles could not be resolved. Glaucoma tubes and posterior-chamber intraocular lens (PCIOL) haptics were imaged below the iris plane. CONCLUSIONS: Cross-sectional AS-OCT adequately imaged the components of the assembled KPro in vivo, as well as its interaction with surrounding anterior-segment structures. It allowed visualization of the anterior chamber, iris, and angle, essential in the postoperative care of these patients. Coronal AS-OCT showed graphic en face images of the KPro device and suspected retrokeratoprosthetic membranes. UBM, on the other hand, adequately imaged glaucoma tube shunts and PCIOL haptics beneath the iris plane.     

Relationship between filtering bleb vascularization and surgical outcomes after trabeculectomy: an optical coherence tomography angiography study

Graefe's Archive for Clinical and Experimental Ophthalmology - To explore the relationship between the bleb vasculature and surgical outcome after trabeculectomy (TRAB) using optical coherence...     

Filtering bleb evaluation with slit-lamp-adapted 1310-nm optical coherence tomography

PURPOSE: Investigation of slit-lamp-adapted 1310-nm optical coherence tomography (OCT) as an in vivo imaging device in the postoperative course of glaucoma surgery. METHODS: Postoperative images of filtering blebs and deep sclerectomies and their healing processes were qualitatively evaluated with a slit-lamp-adapted anterior segment OCT (AS-OCT; Heidelberg Engineering, Heidelberg, Germany) in 28 patients. Ophthalmologic examinations included slit-lamp examination, applanation tonometry, and slit-lamp photography. The OCT scans were qualitatively correlated with the morphologic and functional outcome of the filtering bleb. RESULTS: 1310-nm OCT was able to demonstrate the internal structure and the dimensions of filtering blebs, as well as the scleral flap and the deep sclerectomy location including Descemet membrane. Functioning filtering blebs showed a low OCT signal, small fluid-filled cysts, superficial microcystic layer, and a slack internal texture. High internal reflectivity indicated an earlier scarring of the filtering bleb. Nonfunctioning filtering blebs delivered a high OCT signal, no or few cysts, and a dense internal texture. These different OCT patterns correlated with the clinical outcome. CONCLUSIONS: Slit-lamp-adapted 1310-nm OCT allowed the noncontact observation and documentation of the postoperative healing course of filtering blebs after glaucoma surgery. Internal structures of the filtering bleb and deep sclerectomies could be visualized. Functioning and dysfunctioning filtering blebs delivered different OCT pattern and correlated with the clinical outcome. This could be a new way to assess the postoperative healing process with the possibility of earlier intervention in cases of impending scarring.     

Morphology of functioning trabeculectomy blebs using anterior segment optical coherence tomography

Purpose:

To image trabeculectomy blebs using anterior segment optical coherence tomography (AS-OCT), and to correlate the bleb morphologic features at one month postoperatively with bleb function at six months.

Materials and Methods:

This prospective, observational study included 56 eyes undergoing trabeculectomy with MMC, followed up for minimum of six months. Postoperatively, bleb imaging was done using AS-OCT at one and six month. Bleb morphology was assessed for bleb wall reflectivity, bleb pattern in multiform reflectivity, visibility of drainage route and presence of hyper-reflectivity area. Bleb function was considered successful if IOP was <18 mmHg without medication at six month. Bleb morphology one month postoperatively was correlated with bleb function at six months.

Results:

At six months successful bleb function was noted in 44 (81.5%) eyes. Morphology of bleb at one month showed uniform bleb wall reflectivity in 6 eyes (11%) and multiform wall reflectivity in 48 eyes (89%). In eyes with multiform wall reflectivity, microcysts with multiple layers was seen in 26 eyes (48%), microcysts with subconjunctival separation in 12 eyes (22%) and only microcyst in 10 eyes (19%). When bleb features at one month were correlated with the bleb function at six months, logistic regression analysis revealed that blebs with multiform reflectivity with multiple internal layers with microcysts were associated with higher chances of success (P < 0.001).

Conclusion:

AS-OCT demonstrated early bleb morphological features that may be used to predict the functioning of a bleb. Multiform bleb wall reflectivity with a pattern of multiple internal layers and microcysts was associated with increased chances of success of a bleb.     

Three-dimensional anterior segment optical coherence tomography of filtering blebs after trabeculectomy

PURPOSE: To evaluate trabeculectomy blebs by using 3-dimensional anterior segment optical coherence tomography (OCT). METHODS: We prospectively examined 4 eyes of 4 patients who developed filtering blebs after trabeculectomy. A 1310-nm high-speed OCT prototype was used to image the 3-dimensional structure of the filtering blebs. RESULTS: The 3-dimensional structure of the filtering blebs was clearly observed in the OCT images. Three types of filtering blebs were observed: diffuse blebs in 2 eyes, an encapsulated bleb in 1 eye, and a nonfunctioning cystic bleb in 1 eye. The volume of each bleb was 9.97, 1.10, 0.76, and 0.88 mm3, respectively. En-face OCT images clearly showed the aqueous outflow channels at the margins of the scleral flaps. CONCLUSION: Three-dimensional OCT allows objective and noninvasive assessment of filtering blebs after trabeculectomy.     

A pilot study on slit lamp-adapted optical coherence tomography imaging of trabeculectomy filtering blebs

Background Our study aims to identify anatomical characteristics of glaucoma filtering blebs by means of slit lamp-adapted optical coherence tomography (SL-OCT) and to identify new parameters for the functional prognosis of the filter in the early post-operative period. Methods Patients with primary open-angle glaucoma, aged 18 years and older, scheduled for primary trabeculectomy at the Department of Ophthalmology, Radboud University Nijmegen Medical Centre, were considered for our study. All patients underwent standardized trabeculectomy with intra-operative application of mitomycin C. The filtering blebs were evaluated clinically and with SL-OCT on day 1 and 1, 2, 4 and 12 weeks following surgery. The resulting data were analysed and weighed against surgical success. To better understand the SL-OCT data a small comparative histologic study was performed. Results The study included 20 eyes of 20 patients. After completion of our study, 15 eyes of 15 patients (mean age±SD 67 ± 16 years) were eligible for data analysis and 5 eyes missed at least one follow-up visit. Filtering surgery was considered successful (intraocular pressure ≤ 21 mmHg without antiglaucomatous medication) in 11 of 15 eyes. SL-OCT frequently demonstrated multiple hypo-reflective layers within Tenon’s capsule (“striping” phenomenon) in the first post-operative week. Presumably, these layers corresponded with drainage channels in the histological specimen. These channels were present in functional filters but not in the failures. In addition, the visualisation of the sclera below the filtering zone was better defined in failures compared with successful filtering blebs (“shading” phenomenon). We observed no differences in the volume and clinical aspect of the blebs in the successful group compared with the unsuccessful group. Conclusions Successful filtering blebs show characteristic optical properties on SL-OCT. These phenomena suggest a diffusely enhanced fluid content and the presence of intra-bleb drainage channels in functional filtering blebs. Meeting presentation Presented in part as a poster at the 1st World Glaucoma Congress, Vienna, Austria, July 2005. Financial disclosure Medical Workshop, Groningen, Netherlands, made the slit lamp-adapted optical coherence tomography device available to one of the authors (T. Theelen) with support from the manufacturer, Heidelberg Engineering, Lübeck, Germany. There are no other competing interests.     

Effect of trabeculectomy on RNFL thickness and optic disc parameters using optical coherence tomography

Purpose

To study the change in retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) parameters using optical coherence tomography (Stratus OCT 3) after trabeculectomy in adult patients with glaucoma.

Methods

A total of 17 patients with glaucoma undergoing trabeculectomy were recruited. Average and quadrant RNFL thickness measurements, vertical integrated rim area, horizontal integrated rim width, disc area, cup area, and rim area were measured using Stratus OCT within a week before surgery and at 1 week, 1 and 3 months postoperatively. Main outcome measures were change in RNFL and ONH parameters. Pre- and postoperative values were analysed using the Wilcoxon signed-rank test.

Results

Intraocular pressure (IOP) reduced from 30.23±9.02 mm Hg preoperatively to 9.52 ±2.42 mm Hg at 1 week, 12.35±4.59 mm Hg at 1 month, and 13.6 ±2.31 mm Hg at 3 months after trabeculectomy. A significant increase in average (P=0.019) and inferior RNFL (P=0.038) thickness was observed 1 week after surgery. At 3 months postoperatively, they had reverted to preoperative values. RNFL thickness change had no correlation with IOP change. Mean optic disc cup area decreased from 2.39±0.52 mm² preoperatively to 2.14±0.52 mm² at 1 week (P=0.022), 2.22±0.53 mm² at 1 month (P=0.038), and 2.27±0.60 mm² at 3 months (P=0.071). No significant change was found in other ONH parameters.

Conclusions

Short-term fluctuations were noted in RNFL thickness and ONH postoperatively following glaucoma filtration surgery. RNFL thickness temporarily increased and cup area decreased but the values reverted to normal within 3 months.     

原发性急性闭角型青光眼周边虹膜切除和滤过性手术前后眼前段结构参数对比分析

目的 观察原发性急性闭角型青光眼(acute primary angle closure glaucoma,APACG)周边虹膜切除(peripheral iridectomy,PI)和小梁切除术(Trabeculectomy,Trab)手术前后眼前段结构参数的改变.方法 临床病例对照研究.对2009年6～12月在中山大学眼科中心连续性收集57例57只眼APACG患者,周边虹膜粘连(peripheral anterior synechiae,PAS)范围≤6个钟点者行PI术,PAS范围＞6个钟点者行小梁切除术,术前及术后3月行眼前段光学相干断层扫描仪(anterior segment optical coherence tomograph,AS-OCT)眼前段扫描.比较两组组内及组间术前及术后的中央前房深度(central anterior chamber depth,ACD)、房角开放距离(angle opening distarce,AOD)、小梁网虹膜间面积(Trabecular iris area,TISA)、房角隐窝面积(angle recess area,ARA)、前房宽度(anterior chamber width,ACW)、前房容积(anterior chamber volume,ACV)和晶状体矢高(crystalline lens rise,CLR).结果 两组间的平均年龄(t=-0.176,P=0.862)和性别(P=0.390)之间无统计学差异.术前及术后周边虹膜切除术组的TISA和ARA均明显大于小梁切除术组(P=0.013～0.049).周边虹膜切除术组术后AOD、TISA、ARA及ACV较术前明显增加(P＜0.001～0.044),ACD、ACW及CLR手术前后无明显变化(P=0.102～0.609).小梁切除术组术后除ACV较术前的增加有统计学意义外(P＜0.001),余参数手术前后无变化(P=0.056～0.585).结论 周边虹膜切除术和小梁切除术均可增加APACG眼的ACV,但ACD和CLR无明显改变.周边虹膜切除术术后APACG眼房角参数改善,但小梁切除术对房角参数的改变无明显影响.

Abstract：

Objective To evaluate the changes in antenor segment configuration after peripheral iridectomy (PD or trabeculectomy (Trab) in acute primary angle closure glaucoma (APACG). Methods FiRy-seven eyes of 57 patients with APACG were successive collected. PI was performed to those patients with the clock hours of peripheral anterior synechiae (PAS) 6, while Trab was performed to those patients with the clock hours of PAS >6. Anterior segment optical coherence tomography (AS-OCT) examination was performed before and 3 months after PI/Trab to compare central anterior chamber depth (ACD), angle opening distance (AOD), trabecular iris area (TISA), angle recess area (ARA), anterior chamber width (ACW), anterior chamber volume (ACV) and crystalline lens rise (CLR). Results There were no differences in mean age (P 0.862) and male/female ratio (P=0.380) between the 2 groups. After surgery, AOD, TISA, ARA, ACA and ACV increased significantly (P ＜0.001～0.044), while no changes were found in ACD, ACW and CLR (P=0.102～0.609) in PI group. In Trab group, ACV increased significantly postoperation (P ＜0.001) while other parameters shown no changes. Conclusions Both surgery of PI and Trab can increase ACV; PI can improve the anterior angle parameters in APACG, but Trab surgery shows no changes of those parameters.     

脉络膜肿瘤的OCT及OCTA表现

相干光断层扫描（optical coherence tomography,OCT）技术可用于脉络膜肿瘤（脉络膜黑色素瘤、脉络膜转移癌、脉络膜血管瘤、脉络膜骨瘤等）的观察和诊断,其对肿瘤表面形态、视网膜水肿程度、视网膜下液、光感受器层改变、视网膜结构的完整性、脉络膜厚度、异常反射结构等做定性及定量描述。相干光断层扫描血管成像（OCT angiography,OCTA）可对瘤体及其周围组织的视网膜脉络膜血流特点进行观察,并在一定程度上指导脉络膜肿瘤的治疗。（国际眼科纵览,2021, 45： 499-505）     

慢性闭角型青光眼周边虹膜切除和滤过性手术前后眼前段结构参数的对比研究

目的观察原发性慢性闭角型青光眼(CPACG)周边虹膜切除和小梁切除术手术前后眼前段结构参数的改变。设计前瞻性比较性病例系列。研究对象中山眼科中心连续CPACG患者45例53眼。方法患者周边虹膜粘连范围≤6个钟点者行周边虹膜切除术,>6个钟点者行小梁切除术,术前及术后3个月行眼前段光学相干断层扫描(AS-OCT)检查。比较两种术式术前及术后的眼前段AS-OCT检查参数。主要指标中央前房深度(ACD)、前房角开放距离(AOD)、小梁网虹膜间面积(TISA)、前房角隐窝面积(ARA)、前房宽度(ACW)、前房面积(ACA)、前房容积(ACV)和晶状体矢高(CLR)。结果周边虹膜切除术后ARA(0.078±0.036 mm2)、ACA(15.409±2.892 mm2)及ACV(91.021±22.387 mm3)较术前(ARA 0.065±0.024 mm2,ACA 13.945±2.633 mm2,ACV83.445±21.791 mm3)明显增加(t=-8.015～-2.727,P=0.000～0.042),但手术前后AOD、TISA、ACD、ACW和CLR无变化(t=-1.374～0.561,P=0.102～0.774)。小梁切除手术前后各眼前段生物学参数的变化均无统计学意义(t=-1.700～-0.002,P=0.388～0.998)。结论原发性慢性闭角型青光眼周边虹膜切除术术后前房角隐窝面积、前房面积和前房容积增加,但小梁切除术后眼前段参数无明显改善。     

Imaging of trabeculectomy blebs with Visante anterior segment optical coherence tomography after digital ocular compression

Purpose  

We investigated changes in intrableb morphology of functioning trabeculectomy blebs with anterior segment optical coherence tomography (AS-OCT) after digital ocular compression.