Intraoperative Optical Coherence Tomography Guided Bleb Needling

A modified trabeculectomy technique with direct filtration into the Tenon's capsule

OBJECTIVE

To report the surgical outcomes of a modified trabeculectomy technique involving implanting the Tenon's layer under the scleral flap.

DESIGN

Prospective, interventional case series.

PARTICIPANTS

51 eyes with medically uncontrolled glaucoma were enrolled for this study. A new trabeculectomy technique, the Tenon's filtration technique for trabeculectomy (TFT-LEC) was used in 26 eyes, while a conventional procedure, normal trabeculectomy (N-LEC), was used for 25 eyes.

METHODS

Intraocular pressure (IOP) control, the number of glaucoma medications, the need for additional interventions, and postoperative complications were assessed.

RESULTS

Twelve months postoperatively, the mean IOP was 13.5 ± 0.5 mmHg in the TFT-LEC group and 15.4 ± 0.5 mmHg in the N-LEC group (p = 0.13). The TFT-LEC group required an average of 1.3 ± 1.0 additional glaucoma medications (21 cases required only ripasudil) postoperatively, with no cases of bleb needling revision or reoperation. The N-LEC group required an average of 1.7 ± 1.5 glaucoma medications (p = 0.43) compared to TFT-LEC group, eight cases (32%) required bleb needling revision (p = 0.002), and one case (4%) of reoperation (p = 0.49). The complications in the TFT-LEC group included shallow anterior chamber in six (23 %) cases (p = 1.00) compared to N-LEC group, choroidal detachment in two (8%) cases (p = 0.42), and anterior chamber hemorrhage in seven (27%) cases (p = 0.29). None of these complications affected visual function.

CONCLUSIONS

This new technique involving implanting the Tenon's layer under the scleral flap may improve the postoperative outcomes of trabeculectomy.

Intraoperative OCT to check the correct postimplant position of PreserfloTM

INTRODUCTION

This study was designed to examine the capacity of intraoperative optical coherence tomography (OCT) to predict the postimplant position of the glaucoma drainage device PreserfloTM.

METHODS

13 eyes (mean age 65.42 (14.89) years) underwent PreserfloTM (Santen, Osaka, Japan) placement. Before surgery, participants were subjected to a comprehensive ophthalmic examination (intraocular pressure (IOP), cup to disk ratio (C/D), visual field, OCT, endothelial cell count). Anterior segment OCT scans were obtained intraoperatively using a Rescan 700 OCT system (Carl Zeiss Meditec, Inc., Oberkochen, Germany). One day postsurgery, anterior segment OCT using the Spectralis OCT (Heidelberg Engineering GmbH) was performed in a sitting position to capture the same chamber cross-section as before. The main outcome variables were tube-endothelium distance (T-E) and tube length (TL) in the anterior chamber measured using both OCT systems. Correlation between intraoperative and office measurements was examined through Pearson correlation (r) and intraclass correlation coefficients (ICC).

RESULTS

Mean intraoperative and in-office T-E were 625.26 (SD 366.60) versus 561.16 (SD 364.62) µm respectively (p = 0.540). Intraoperative and in-office anterior chamber TL were 1386 (SD 701.82) and 1433.91 (SD 713.55) µm, respectively (p = 0.029). Excellent correlation was observed between both sets of T-E (r = 0.992; p = 0.008) and TL (r = 0.984; p = 0.016) values. Both OCT systems showed good agreement yielding ICCs of 0.992 (p < 0.001) for T-E and 0.995 (p = 0.001) for TL.

DISCUSSION

Excellent correlation was observed between our intraoperative and postoperative OCT measurements. These results support the usefulness of intraoperative OCT to confirm the correct position of an implanted PreserfloTM microshunt.

Intraoperative optical coherence tomography-guided transconjunctival bleb suturing - A minimally invasive technique for managing overfiltering bleb

With the recent advancement in technologies, real-time integrated intraoperative optical coherence tomography (iOCT) microscopes are available, which facilitates surgical precision and also reduces the risk of complications. Two glaucoma patients with advanced glaucomatous optic neuropathy, who underwent uneventful trabeculectomy with 0.02% mitomycin C, developed persistent hypotony postoperatively till 4-6 weeks. On clinical examination, visual acuity was 1/60 with low intraocular pressure (IOP) of 4 mmHg. Elevated, overfiltering bleb was seen on slit-lamp examination, along with hypotonous maculopathy. Anterior segment optical coherence tomography (AS-OCT) showed multiple large hyporeflective fluid spaces suggestive of overfiltering bleb. Considering the risk of choroidal detachment and further deterioration of vision, iOCT-guided transconjunctival bleb suturing was planned. iOCT helped to identify the exact location of scleral flap, and transconjunctival suturing was done with successful outcomes in terms of improved IOP and visual acuity.

Clinical applications for intraoperative optical coherence tomography: a systematic review

In this systematic review, we provide an overview of the current state of intraoperative optical coherence tomography (iOCT). As iOCT technology is increasingly utilized, its current clinical applications and potential uses warrant attention. Here, we categorize the findings of various studies by their respective fields, including the use of iOCT in vitreoretinal surgery, corneal surgery, glaucoma surgery, cataract surgery, and pediatric ophthalmology. The trend observed in recent decades towards performing minimally invasive ophthalmic surgery has caused practitioners to recognize the limitations of using a conventional surgical microscope for intraoperative visualization. Thus, the superior visualization provided by iOCT can improve the safety of these surgical techniques and promote the development of new minimally invasive ophthalmic surgeries. Landmark prospective studies found that iOCT can significantly affect surgical decision making and can cause a subsequent change in surgical strategy, and the use of iOCT has potential to improve surgical outcome. Despite these advantages, however, iOCT is still a relatively new technique, and beginning users of iOCT can encounter limitations that can preclude their reaching the full potential of iOCT and in this respect several improvements are needed.

Intraoperative Optical Coherence Tomography-Guided Bleb-sparing Epithelial Exchange: A Modified Approach

With the advent of newer technologies, real-time anterior segment optical coherence tomography (OCT) integrated with the operating microscope has become possible. We are proposing the technique of bleb revision with greater precision under direct visualization of bleb anatomy and extent of tissue depth allowing better localization and easy maneuvering with lesser complications. In this surgical technique, bleb revision was performed using intraoperative real-time OCT incorporated in OPMI LUMERA 700 microscope. Live surgical and OCT view were seen on a common screen together. A moderately elevated, diffuse functional bleb was noted after three months of bleb revision in both cases with controlled intraocular pressure. Intraoperative OCT-guided bleb-sparing epithelial exchange is an adjunctive technique for bleb repair surgery with an increased precision of surgery which can reduce complications, minimize surgical time and maximize surgical outcome.

Needling revision with marking maneuver to locate the scleral flap

PURPOSE

To report a variation of the classical needle revision maneuver with an external marking of the scleral flap, augmented with mitomycin C (MMC) in failed non penetrating deep sclerectomy (NPDS).

METHOD

This observational prospective pilot study included five consecutive patients who underwent an MMC needling revision of failed NPDS with the external marking of the scleral flap. All participants underwent a complete ophthalmologic examination and data were collected preoperatively as well as 1 day, 1 week and 1 month after the surgery. The surgical site was also evaluated during the procedure.

RESULTS

A significant reduction of IOP and antiglaucomatous medication from preoperative levels was detected at the end of the follow-up period. Regarding the surgical site, we succeed in locating the scleral flap and observing the bleb formation in all cases. No significant subconjunctival bleeding was detected.

CONCLUSION

This variation of the classical needling technique seems to improve intrasurgical visualization and reduces complications, which might lead to an improvement in surgical success.

Intraoperative optical coherence tomography in anterior segment surgery

Intraoperative optical coherence tomography (iOCT) enables real-time visualization of ocular structures during surgery and enhances our understanding of intraoperative dynamics. iOCT aids in decision-making during various anterior segment surgeries, and its efficacy and feasibility in anterior lamellar keratoplasty and endothelial keratoplasty is well established. The landmark DISCOVER study observed that iOCT altered the surgeon decision in 38% of cases undergoing lamellar keratoplasty and provided guidance regarding the need for secondary surgical intervention. iOCT also finds an application in phacoemulsification wherein it helps to assess corneal incisions, intralenticular pressure, and posterior capsule integrity during nuclear emulsification. iOCT aids in the visualization of angle structures during placement of tubes and shunts in glaucoma surgeries and allows precise creation of partial thickness scleral flaps. In addition, iOCT helps in establishing a diagnosis, as well as provide intraoperative guidance, in pediatric patients who are not cooperative for examination. The role of iOCT in refractive surgeries and ocular surface disorders is increasingly being evaluated. The limitations of present-day iOCT systems are related to instrument compatibility, automated tracking of the surgical field, and on-table volumetric analysis of the real-time images. Technological advances may facilitate complete integration of OCT in the surgical microscopes for all surgical procedures.

Observation of Gonio Structures during Microhook Ab Interno Trabeculotomy Using a Novel Digital Microscope with Integrated Intraoperative Optical Coherence Tomography

Purpose

Observation of ocular structures using microscope-integrated intraoperative optical coherence tomography (iOCT) has been adopted. Using the novel digital ophthalmic microscope, ARTEVO 800 with iOCT, we tested the feasibility of trabecular meshwork (TM) imaging during microhook ab interno trabeculotomy, a minimally invasive glaucoma surgery.

Methods

The nasal and temporal sides of the TM/inner wall of Schlemm's canal were incised more than 3 clock hours in 14 glaucomatous eyes of 10 patients. To observe the trabeculotomy site, iOCT was performed with the real-time five-line scan mode under observation using a Swan-Jacob gonioprism lens. The success of the imaging and visibility of the trabeculotomy cleft and its incisional patterns (i.e., anterior, middle, or posterior pattern) were determined by reviewing the iOCT video files.

Results

OCT images of the region of interest were acquired successfully in 100% of the 28 nasal or temporal sides in 14 eyes, although the trabeculotomy cleft was not visualized in four (14%) sides due to blockage of the OCT signal by a blood clot. Based on the predominant locations of the TM flaps in 24 of the acquired images, the trabeculotomy clefts were classified as anterior incisional patterns in 13 (54%), middle incisional patterns in nine (38%), and posterior incisional patterns in two (8%).

Conclusion

Intraoperative imaging of the gonio structures including the trabeculotomy cleft was feasible using the ARTEVO 800 with iOCT in combination with a gonioprism.

What Is the Impact of Intraoperative Microscope-Integrated OCT in Ophthalmic Surgery? Relevant Applications and Outcomes. A Systematic Review

Background: Optical coherence tomography (OCT) has recently been introduced in the operating theatre. The aim of this review is to present the actual role of microscope-integrated optical coherence tomography (MI-OCT) in ophthalmology. Method: A total of 314 studies were identified, following a literature search adhering to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. After full-text evaluation, 81 studies discussing MI-OCT applications in ophthalmology were included. Results: At present, three microscope-integrated optical coherence tomography systems are commercially available. MI-OCT can help anterior and posterior segment surgeons in the decision-making process, providing direct visualization of anatomic planes before and after surgical manoeuvres, assisting in complex cases, and detecting or confirming intraoperative complications. Applications range from corneal transplant to macular surgery, including cataract surgery, glaucoma surgery, paediatric examination, proliferative diabetic retinopathy surgery, and retinal detachment surgery. Conclusion: The use of MI-OCT in ophthalmic surgery is becoming increasingly prevalent and has been applied in almost all procedures. However, there are still limitations to be overcome and the technology involved remains difficult to access and use.

Intra-operative optical coherence tomography in glaucoma surgery-a systematic review

The application of the OCT in clinical ophthalmology has expanded significantly since its introduction more than 20 years ago. There has been recent growing interest in the application of intra-operative optical coherence tomography (iOCT). The iOCT's ability to enhance visualisation and depth appreciation has the potential to be further exploited in glaucoma surgery, especially with the emergence of Minimally Invasive Glaucoma Surgery (MIGS)-to facilitate targeted device placement and fine surgical manoeuvres in the angles, the sub-conjunctival layer and the suprachoroidal space. Hence, this study aims to appraise the current literature on the applications of iOCT in glaucoma surgery. A total of 79 studies were identified following a literature search adhering to PRISMA guidelines. After full text evaluation, 10 studies discussing iOCT use in glaucoma surgery were included. Traditional glaucoma filtering procedures reviewed included trabeculectomy surgery, goniosynechiolysis, bleb needling and glaucoma drainage device implantation. MIGS procedures reviewed included canaloplasty, trabecular aspiration, ab-interno trabectome and the XEN45 gel stent. iOCT use in ophthalmic surgery is becoming increasingly prevalent and has already been applied in various surgeries and procedures in the field of glaucoma. With the greater adoption of MIGS, iOCT may further contribute in facilitating surgical techniques and improving outcomes. While iOCT offers many advantages, there are still limitations to be overcome-iOCT technology continues to evolve to optimise imaging quality and user-experience.

[Optical coherence tomography for examination of glaucoma surgery site]

The article reviews the results of using optical coherence tomography (OCT) - a non-invasive non-contact examination method for obtaining a tomographic slice image of the site of glaucoma surgery. The method helped reveal the functional relationships between the newly created outflow pathways and various parameters of the filtering bleb such as its linear dimensions, wall structure, presence of microcysts, position of drainage, etc. Due to its high resolution and noninvasiveness, OCT can be reliably used to examine the structure of aqueous outflow pathways in different postoperative periods with accuracy close to morphometric. The amount of data that had been obtained with the method has allowed the creation of new classifications and clarification of OCT-relevant prognostic signs for glaucoma surgery site.

Innovations in glaucoma surgery from Dr. Rajendra Prasad Centre for Ophthalmic Sciences

Trabeculectomy surgery is the current standard of care in glaucoma for achieving a low target intraocular pressure if medical therapy is not adequate. Augmentation of trabeculectomy with antimetabolites brought a revolutionary change in the long-term success rates of trabeculectomy, but along with it came a plethora of complications. There still is a big window for therapeutic innovations on this subject. The foremost target for these innovations is to modulate the wound healing response after glaucoma drainage surgery. Achieving the desired balance between long-term success of filtering blebs versus early failure due to scarring of blebs and hypotony due to dysfunctional filtering blebs poses a unique challenge to the ophthalmologists. Alternatives to trabeculectomy such as glaucoma drainage devices and minimally invasive glaucoma surgeries cannot solve the problem of glaucoma blindness in our country, mainly due to their unpredictable results and unfavorable cost-benefit ratio. In this article, we present a summary of our innovations in glaucoma surgery to advance patient care by making it more effective, safer, and economical.