Real-time Optical Coherence Tomography Incorporated in the Operating Microscope during Cataract Surgery.

A 55-year-old male presented with reduced vision due to senile cataract. The patient consented to undergo real-time intraoperative anterior segment-optical coherence tomography (AS-OCT) during phacoemulsification with intraocular lens (IOL) implantation. Images were captured at various points during the surgery. The use of AS-OCT incorporated into the surgical microscope was evaluated as an adjunct to cataract surgery. We were able to successfully evaluate, in real-time, wound architecture, the attachment of Descemet's membrane, the posterior capsule, and IOL position. Real-time AS-OCT can be used to proactively address potential complications and verify IOL placement intraoperatively.

Introduction

Cataract surgery is the most commonly performed procedure worldwide. Studies have shown that the volume of cataract surgery has increased commensurately with the introduction of newer techniques and technology over the past two decades.[12] For example, the introduction of phacoemulsification and femtosecond laser for cataract surgery stimulated significant research on improving outcomes and minimizing complications. Similarly, the recent introduction of anterior segment-optical coherence tomography (AS-OCT) incorporated into the operating microscope may have a significant beneficial effect in cataract surgery. AS-OCT may be utilized intraoperatively in high-risk cataract surgery cases such as in case of compromised cornea where visualization is impaired. In addition, it may also improve outcomes in routine cataract cases. In this case report, we describe the use of real-time AS-OCT (OPMI LUMERA 700 and RESCAN 700 [Carl Zeiss Meditec AG, Jena, Germany]) during cataract surgery.

Case Report

A routine cataract case was selected. The case was a 55-year-old male with visual acuity 20/100, −2 D refraction with a clear cornea, deep anterior chamber, and +2 nuclear sclerosis. The retina was unremarkable on dilated funduscopy and the patient had no other coexisting ocular pathologies.

Institutional review board approval was obtained. The patient consented to undergo cataract surgery with intraoperative OCT. An experienced cataract surgeon performed the cataract surgery with implantation of 21 D monofocal intraocular lens (IOL) using the OPMI LUMERA 700 and RESCAN 700 microscope with real-time OCT throughout the surgery. The OCT is integrated into the microscope system and can be controlled with a foot pedal. The Infiniti (Alcon Inc., Fort Worth, TX, USA) phacoemulsification unit was used during the surgery. The case was video recorded, and OCT images were captured during each step of the cataract surgery.

Intraoperative, real-time AS-OCT was used during phacoemulsification and to confirm the integrity of the AS structures. We mainly focused on the wound, Descemet's membrane, groove, hydrodissection and the posterior capsule, and IOL position.

Phacoemulsification was uneventful. We were able to evaluate the wound architecture [Figure 1]. Descemet's membrane attachment was confirmed throughout the surgery. The integrity of the posterior capsule could be assessed [Figure 2]; the IOL position at the end of the surgery and stromal hydration could also be evaluated [Figure 3]. OCT images showed that stromal hydration mainly involved the posterior cornea. We were unable to assess the depth of the groove (D) to determine the fragmentation time. The fluid wave during the hydrodissection maneuver was difficult to capture. The patient was examined on the 1st postoperative day and had a visual acuity of 20/40 without any postoperative complication.

Figure 1

Evaluation of the corneal wound with real-time anterior segment-optical coherence tomography during cataract surgery

Figure 2

Real-time anterior segment-optical coherence tomography showing posterior capsule bowing, confirming patency and an intact Descemet's membrane

Figure 3

Real-time anterior segment-optical coherence tomography image showing the effect of stromal hydration. Images of the nasal aspect of the anterior segment show no edema, the temporal cuts show posterior swelling from stromal hydration

Discussion

Phacoemulsification is a safe and efficacious procedure; however, intraoperative complications can occur.[1] Some of these complications may lead to significant ocular morbidity. Hence, adjunct medical and surgical intervention may be required if the complications are not recognized intraoperatively. For example, wound leak may lead to serious complications such as endophthalmitis, resulting in irreversible vision loss.

The rate of posterior capsular rupture (PCR) is approximately 2%.[34]

The incidence of IOL dislocation is 0.1%.[5]

Intraoperative OCT can be helpful in visualizing these complications, allowing the surgeon to address the event immediately. Slight displacement of the IOL or IOL tilt can be identified with intraoperative OCT. This is especially pertinent in cases of toric and multifocal lenses where mild displacement can cause significant visual and refractive sequelae. Well-centered IOL placement is imperative for premium IOLs for the desired refractive outcome.

This case report presents the incorporation of real-time AS-OCT during phacoemulsification as a diagnostic tool to aid surgeons in mitigating complications. We believe that this technology will allow the surgeon to proactively address complications during the procedure and improve outcomes. Early detection of these complications will allow timely treatment during the surgery.

Chan et al. used AS-OCT to identify eyes with posterior polar cataract at high risk for PCR during cataract extraction.[6] They concluded that the AS-OCT can be used to grade posterior polar cataracts and identify eyes at high risk for PCR, allowing better surgical planning and appropriate preoperative counseling.[6] Xia et al. evaluated a clear corneal incision with AS-OCT and reported detailed measurements and imaging of the ultrastructures of the incision.[7] Other studies evaluated the effect of stromal hydration postoperatively with AS-OCT.[89] Researchers have been investigating the use of OCT during AS surgery and posterior segment surgery using animal models and cadaver eyes.[10]

The use of real-time AS-OCT for AS surgery is a relatively new modality, and further investigation is required to determine its applications in AS surgery. Previous studies have reported its use in guiding specific steps such as air injection and intrastromal fluid drainage.[1112] In this case report, we describe AS-OCT during cataract surgery, and our impression is that AS-OCT is a promising tool that needs to be explored.

Conclusion

Real-time OCT incorporated into the operating microscope is a beneficial tool that can be utilized during cataract surgery. It allows evaluation of the posterior capsule and Descemet's membrane. As with any new technology, it has its own disadvantages including increased surgical time and a learning curve.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.