Christine Shieh

Live volumetric (4D) visualization and guidance of in vivo human ophthalmic surgery with intraoperative optical coherence tomography

Minimally-invasive microsurgery has resulted in improved outcomes for patients. However, operating through a microscope limits depth perception and fixes the visual perspective, which result in a steep learning curve to achieve microsurgical proficiency. We introduce a surgical imaging system employing four-dimensional (live volumetric imaging through time) microscope-integrated optical coherence tomography (4D MIOCT) capable of imaging at up to 10 volumes per second to visualize human microsurgery. A custom stereoscopic heads-up display provides real-time interactive volumetric feedback to the surgeon. We report that 4D MIOCT enhanced suturing accuracy and control of instrument positioning in mock surgical trials involving 17 ophthalmic surgeons. Additionally, 4D MIOCT imaging was performed in 48 human eye surgeries and was demonstrated to successfully visualize the pathology of interest in concordance with preoperative diagnosis in 93% of retinal surgeries and the surgical site of interest in 100% of anterior segment surgeries. In vivo 4D MIOCT imaging revealed sub-surface pathologic structures and instrument-induced lesions that were invisible through the operating microscope during standard surgical maneuvers. In select cases, 4D MIOCT guidance was necessary to resolve such lesions and prevent post-operative complications. Our novel surgical visualization platform achieves surgeon-interactive 4D visualization of live surgery which could expand the surgeon’s capabilities.

Real-Time Microscope-Integrated OCT to Improve Visualization in DSAEK for Advanced Bullous Keratopathy.

Purpose: To report the intraoperative use of microscope-integrated optical coherence tomography (MIOCT) to enable visualization for Descemets stripping automated endothelial keratoplasty (DSAEK) in 2 patients with advanced bullous keratopathy. Methods: Patient 1 was an 83-year-old female and patient 2 was a 28-year-old male both with limited vision and significant pain from bullous keratopathy who underwent palliative DSAEK. Because of the severity and chronicity of the corneal decompensation in both patients, the view past the anterior cornea was negligible using standard microscope illumination techniques. We used spectral-domain (Patient 1) and swept-source (Patient 2) MIOCT, both of which rely on infrared illumination, to visualize key parts of the DSAEK procedure. Results: Graft insertion, unfolding, tamponade, and attachment could be dynamically visualized intraoperatively despite the nearly opaque nature of the host corneas. Postoperatively, the grafts remained attached with significant corneal clearing, and there was improvement in visual acuity, and pain relief for both patients. Conclusions: MIOCT is a valuable tool for the corneal surgeon, allowing for DSAEK to be successfully performed even when the surgical microscope view is limited from severe corneal edema, as is often the case in patients with advanced bullous keratopathy. By using MIOCT, these patients can benefit from the advantages of DSAEK despite a clinically opaque cornea, which would otherwise be treated with a penetrating keratoplasty.

4D microscope-integrated OCT improves accuracy of ophthalmic surgical maneuvers

Ophthalmic surgeons manipulate micron-scale tissues using stereopsis through an operating microscope and instrument shadowing for depth perception. While ophthalmic microsurgery has benefitted from rapid advances in instrumentation and techniques, the basic principles of the stereo operating microscope have not changed since the 1930’s. Optical Coherence Tomography (OCT) has revolutionized ophthalmic imaging and is now the gold standard for preoperative and postoperative evaluation of most retinal and many corneal procedures. We and others have developed initial microscope-integrated OCT (MIOCT) systems for concurrent OCT and operating microscope imaging, but these are limited to 2D real-time imaging and require offline post-processing for 3D rendering and visualization. Our previously presented 4D MIOCT system can record and display the 3D surgical field stereoscopically through the microscope oculars using a dual-channel heads-up display (HUD) at up to 10 micron-scale volumes per second. In this work, we show that 4D MIOCT guidance improves the accuracy of depth-based microsurgical maneuvers (with statistical significance) in mock surgery trials in a wet lab environment. Additionally, 4D MIOCT was successfully performed in 38/45 (84%) posterior and 14/14 (100%) anterior eye human surgeries, and revealed previously unrecognized lesions that were invisible through the operating microscope. These lesions, such as residual and potentially damaging retinal deformation during pathologic membrane peeling, were visualized in real-time by the surgeon. Our integrated system provides an enhanced 4D surgical visualization platform that can improve current ophthalmic surgical practice and may help develop and refine future microsurgical techniques.

Atypical Fibroxanthoma of the Bulbar Conjunctiva.

Purpose: To report a rare case of atypical fibroxanthoma (AFX) of the bulbar conjunctiva, and to compare it with previously published cases of conjunctival AFX. Methods: A 37-year-old woman developed a growth on the bulbar conjunctiva of her left eye that increased in size and redness over 4 months and was associated with blurry vision in the left eye, occasional diplopia, irritation of the eye, and increasing tearing. The mass was surgically excised. Results: Slit-lamp examination disclosed a highly vascularized conjunctival lesion with intact lustrous epithelium and a raised nodular edge encroaching on the nasal corneal limbus of the left eye. Pathological examination and immunohistochemistry were diagnostic of AFX. Conclusions: AFX of the conjunctiva is rare, with this being only the fifth example of this neoplasm reported at this site. Complete surgical excision is the most appropriate treatment option.

Efficacy of aflibercept for the treatment of chronic non-ischemic CRVO-associated macular edema after treatment with other anti-VEGF agents

Abstract Objective: To describe a patient with a perfused CRVO that responded to intravitreal aflibercept after prior treatment with intravitreal bevacizumab and intravitreal

Needle Depth and Big-Bubble Success in Deep Anterior Lamellar Keratoplasty: An Ex Vivo Microscope-Integrated OCT Study.

Purpose: To examine big-bubble (BB) formation success rates in deep anterior lamellar keratoplasty (DALK) at various corneal depths using real-time guidance from swept-source, microscope-integrated optical coherence tomography (SS-MIOCT). Methods: The DALK procedure was performed ex vivo with 34 human donor corneoscleral buttons on pressurized artificial anterior chambers using the BB technique employed by Anwar and Teichmann. We inserted a needle under controlled ex vivo conditions to corneal depths ranging from 40% to ≥90% using real-time guidance from SS-MIOCT and injected air. BB success was then determined for each injection. Results: The average needle depth for successful full BB formation was 79.9% ± 3.0% compared with 66.9% ± 2.6% for partial BB formation and 49.9% ± 3.4% for no BB formation (P < 0.0001). Expressed as stroma below the needle tip, this corresponded to 123.9 ± 20.0 &mgr;m for successful full BB formation compared with 233.7 ± 23.8 &mgr;m for partial BB formation and 316.7 ± 17.3 &mgr;m for no BB formation (P < 0.0001). All other variables tested (sex, race, age, endothelial cell density, air injected, needle angle, and central corneal thickness) did not significantly affect BB formation success rates. Conclusions: BB formation in DALK is more successful if needle insertion and air injection occur at deeper corneal depth. However, ≥90% corneal depth was not necessary in this ex vivo model of DALK. SS-MIOCT can be used to accurately guide the needle in real time.

The influence of oral statin medications on progression of glaucomatous visual field loss: A propensity score analysis

ABSTRACT Purpose: The purpose of this study was to examine the association between oral statin use and the progression of open angle glaucoma. Methods: Medical records of 847 Veterans were reviewed to collect statin use history, record demographic and comorbid medical conditions, and review visual fields. Visual field progression was judged by an ophthalmologist masked to statin use history. Progression rates in a propensity score matched cohort were compared between statin users and nonusers using McNemar’s test with the propensity model derived using associated medical and demographic factors. Results: The mean length of observation was 1324 days with a standard deviation of 464 days. Thirty-one per cent of Veterans demonstrated glaucomatous progression in at least one eye, 49% did not demonstrate progression, and 20% were indeterminate. Approximately 74% of subjects had previously used a statin, with this group having heavier burdens of several comorbid medical conditions and less severe baseline glaucoma than nonusers. The matched cohort was 196 statin users and 196 nonusers, each with similar baseline characteristics (standardised differences <0.10). Progression rates were 35% for statin users compared to 56% for nonusers in the matched cohort (McNemar’s p<0.001). Conclusions: In this population of Veterans, glaucoma patients with any history of statin use have lower visual field progression rates than statin nonusers.

Four-dimensional Microscope-Integrated Optical Coherence Tomography to Visualize Suture Depth in Strabismus Surgery.

The authors report the use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT), capable of live four-dimensional (three-dimensional across time) intraoperative imaging, to directly visualize suture depth during lateral rectus resection. Key surgical steps visualized in this report included needle depth during partial and full-thickness muscle passes along with scleral passes. [J Pediatr Ophthalmol Strabismus. 2017;54:e1-e5.].

Four-dimensional microscope- integrated optical coherence tomography to enhance visualization in glaucoma surgeries

We report the first use of swept-source microscope-integrated optical coherence tomography (SS-MIOCT) capable of live four-dimensional (4D) (three-dimensional across time) imaging intraoperatively to directly visualize tube shunt placement and trabeculectomy surgeries in two patients with severe open-angle glaucoma and elevated intraocular pressure (IOP) that was not adequately managed by medical intervention or prior surgery. We performed tube shunt placement and trabeculectomy surgery and used SS-MIOCT to visualize and record surgical steps that benefitted from the enhanced visualization. In the case of tube shunt placement, SS-MIOCT successfully visualized the scleral tunneling, tube shunt positioning in the anterior chamber, and tube shunt suturing. For the trabeculectomy, SS-MIOCT successfully visualized the scleral flap creation, sclerotomy, and iridectomy. Postoperatively, both patients did well, with IOPs decreasing to the target goal. We found the benefit of SS-MIOCT was greatest in surgical steps requiring depth-based assessments. This technology has the potential to improve clinical outcomes.

Management of Chemical Ocular Injuries in Pediatric Patients

Chemical injury to the ocular surface constitutes a hyperacute medical emergency and requires immediate evaluation and treatment. Chemical injury is one of the most common causes of eye injury in the USA in children. Alkali liquids are particularly hazardous, as they can cause saponification resulting in further tissue penetration. Expeditious assessment and treatment is essential to prevent the extensive damage that can quickly result. The management of the sequelae of chemical injury may be challenging as well, ranging from the treatment of corneal thinning or opacification to the management of the damaged ocular surface and limbal stem cell deficiency. Children may also suffer both anisometropia from induced astigmatism and/or deprivational amblyopia from corneal opacification in the injured eye. Patients are at risk for permanent vision loss without close ophthalmologic follow-up. This chapter will address the acute treatment of ocular chemical injuries as well as the management of the sequelae.