Optical coherence tomography angiography findings in patients with ocular and non-ocular Behcet disease / Achados de angiografia por tomografia de coerência óptica em pacientes com doença de Behçet com e sem acometimento ocular

ABSTRACT Purposes: To evaluate the optical coherence tomography angiography findings in patients with Behçet disease with and without ocular involvement. Methods: A total of 40 patients with Behçet disease and 30 healthy controls were enrolled in the study. Retinal vessel density in the superficial capillary plexus and deep capillary plexus, foveal avascular zone area and perimeter, acirculatory index, foveal density, and nonflow area in the superficial retina were automatically measured using the optical coherence tomography angiography software AngioVue and compared between the groups. Results: The mean parafoveal and perifoveal vessel densities in the superficial capillary plexus and deep capillary plexus and foveal density were significantly lower in the eyes with Behçet uveitis compared to the eyes without Behçet uveitis and eyes of the healthy controls. In the eyes with Behçet uveitis, logMAR visual acuity showed a moderate correlation with parafoveal and perifoveal vessel densities and foveal density (r=-0.43, p=0.006; r=-0.62, p<0.001; r=-0.42, p=0.008; respectively). Conclusion: Behçet disease with posterior uveitis was associated with significant perifoveal and parafoveal vascular decrements in the superficial and deep retina.(AU)

RESUMO Objetivo: Avaliar achados de angiografia por tomografia de coerência óptica em pacientes com doença de Behçet com e sem acometimento ocular. Métodos: Foram incluídos 40 pacientes com doença de Behçet e 30 controles saudáveis. A densidade vascular retiniana nos plexos capilares superficial e profundo, a zona avascular foveal, o índice de circularidade, a densidade foveal e a área sem fluxo da retina superficial foram medidos automaticamente, através do software AngioVue para angiografia por tomografia de coerência óptica, e comparados entre os grupos. Resultados: A densidade vascular parafoveal e perifoveal média nos plexos capilares superficial e profundo, bem como a densidade foveal, foram significativamente menores nos olhos com uveíte de Behçet em comparação com os olhos sem uveíte de Behçet e os olhos dos controles saudáveis. Nos olhos com uveíte de Behçet, a acuidade visual logMAR mostrou correlação moderada com a densidade vascular parafoveal e perifoveal e com a densidade foveal (respectivamente, r=-0,43, p=0,006; r=-0,62, p<0,001; e r=-0,42, p = 0,008). Conclusão: A doença de Behçet com uveíte posterior foi associada a decréscimos significativos da vascularização perifoveal e parafoveal na retina superficial e profunda.(AU)

Microscope integrated optical coherence tomography system combined with augmented reality.

One of the disadvantages in microscope-integrated optical coherence tomography (MI-OCT) systems is that medical images acquired via different modalities are usually displayed independently. Hence, surgeons have to match two-dimensional and three-dimensional images of the same operative region subjectively. In this paper, we propose a simple registration method to overcome this problem by using guided laser points. This method combines augmented reality with an existing MI-OCT system. The basis of our idea is to introduce a guiding laser into the system, which allows us to identify fiducials in microscopic images. At first, the applied voltages of the scanning galvanometer mirror are used to calculate the fiducials' coordinates in an OCT model. After gathering data at the corresponding points' coordinates, the homography matrix and camera parameters are used to superimpose a reconstructed model on microscopic images. After performing experiments with artificial and animal eyes, we successfully obtain two-dimensional microscopic images of scanning regions with depth information. Moreover, the registration error is 0.04 mm, which is within the limits of medical and surgical errors. Our proposed method could have many potential applications in ophthalmic procedures.

Punctate inner choroidopathy with atypical presentation / Coroidopatia interna ponteada de apresentação atípica

ABSTRACT We report a case of a young Caucasian female presenting with sudden decrease of vision in the left eye, metamorphopsia, and nasal scotoma. Past medical history revealed a diagnosis of myasthenia gravis, which was currently treated with azathioprine, pyridostigmine, and prednisone. Ophthalmological examination showed fundus with clear vitreous and yellow-white lesions that were isolated and perimacular in the right eye, multiple and confluent in the macula, and punctate in periphery in the left eye. Laboratory workup ruled out the presence of infectious and inflammatory diseases. Fundus autofluorescence disclosed hypoautoflurescence with hyperfluorescent margins corresponding to the lesions observed in both eyes and the angiogram revealed hyperfluorescence since early phases without late leakage. Spectral-domain optical coherence tomography showed areas of intermittent retinal pigment epithelium elevations and disruption of the ellipsoid zone. She was diagnosed with punctate inner choroidopathy and then treated with an increased dose of daily prednisone, which resulted in progressive improvement of her visual acuity and anatomical status.(AU)

RESUMO Relato de caso de mulher jovem, caucasiana, com súbita diminuição de acuidade visual de olho esquerdo, metamorfopsia e escotoma nasal. Apresentava diagnóstico de Miastenia gravis, em tratamento com Azatioprina, Piridostigmina e Prednisona. Fundo de olho demonstrava vítreo límpido e lesões amarelo-esbranquiçadas, perimaculares e isoladas em olho direito, múltiplas e confluentes em mácula e pontilhadas em periferia no olho esquerdo. Exames laboratoriais descartaram doenças infecciosas e inflamatórias. Auto-fluorescência revelou lesões hipoautofluorescentes com margens hiperfluorescentes correspondentes às observadas em ambos os olhos, enquanto angiofluoresceinografia mostrou hiperfluorescência desde as fases iniciais sem vazamento tardio. Tomografia de coerência óptica de domínio espectral revelou áreas de elevações intermitentes do epitélio pigmentar da retina e interrupção da zona elipsóide correspondente. Definiu-se como diagnóstico a coroidopatia interna ponteada, sendo instituído aumento na dose diária de Prednisona, com melhoria progressiva da acuidade visual e do aspecto de fundo de olho da paciente.(AU)

Automated full-field polarization-sensitive optical coherence tomography diagnostic systems for breast cancer.

Intraoperative delineation of breast cancer is a major challenge. An effective breast tissue screening technique may reduce the risk of re-excision during surgery by specifically identifying positive margins. In this study, a high-resolution automated full-field polarization-sensitive optical coherence tomography (FF-PS-OCT) system was developed to classify healthy and malignant human breast tissue from quantitative phase retardation information of the tissues in ex vivo. Twelve breast tissue samples [four healthy, eight malignant (cancerous)] were imaged with the FF-PS-OCT system and the different phase features were extracted from the acquired OCT images (106), based on the differences in the optical signatures of the healthy and malignant tissues. A linear support vector model classifier was trained using 75 images, with a sensitivity of 92.10% and specificity of 89.18% was achieved. Thirty-one images were used to test the model, with a sensitivity of 90.90% and specificity of 85.0% achieved.

Tethered capsule en face optical coherence tomography for imaging Barrett's oesophagus in unsedated patients.

OBJECTIVE: Barrett's oesophagus (BE) screening outside the endoscopy suite can identify patients for surveillance and reduce mortality. Tethered capsule optical coherence tomography (OCT) can volumetrically image oesophageal mucosa in unsedated patients and detect features of BE. We investigated ultrahigh-speed tethered capsule swept-source OCT (SS-OCT), improved device design, developed procedural techniques and measured capsule contact, longitudinal pullback non-uniformity and patient toleration. DESIGN: OCT was performed in 16 patients prior to endoscopic surveillance/treatment. Unsedated patients swallowed the capsule with sips of water and the tether was pulled back to image the oesophagus. SS-OCT at 1 000 000 A-scans/s enabled imaging 10 cm oesophageal lengths in 10 s with 30 µm transverse and 8 µm axial resolution. Capsule contact, longitudinal image coverage and patient toleration were assessed. RESULTS: Nine patients had non-dysplastic BE, three had ablative treatment-naïve neoplasia and four had prior ablation for dysplasia. Dry swallows facilitated capsule transit through the lower oesophageal sphincter (LES), and waiting 10 s before pullback reduced swallow induced LES relaxation. Slow nasal inhalation facilitated capsule retrieval and minimised gag reflex. The procedure was well tolerated. Ultrahigh-speed SS-OCT generated cross-sectional and subsurface en face images showing BE features, while subsurface en face images were required to assess the gastro-oesophageal junction. Candidate features of dysplasia were also identified which could inform follow-up endoscopy/biopsy. BE features were seen in all patients with histologically confirmed BE. Mean capsule contact over BE was 75%±27% for all patients and better in short segment BE. Mean longitudinal image coverage over BE was 59%±34% and better for long segment BE. CONCLUSIONS: Ultrahigh-speed tethered capsule SS-OCT can image en face and cross-sectional mucosal features over wide areas. Device and procedure optimisation improved performance. BE features could be identified in all patients, but limited capsule contact and longitudinal coverage could cause sampling errors for focal pathologies.

Evaluation of choroidal thickness before and after strabismus surgery in paediatric patients by spectral-domain optical coherence tomography.

AIM: This study aimed to determine the effects of strabismus surgery on choroidal thickness in paediatric patients with Spectral Domain-Optical Coherence Tomography (SD-OCT). MATERIAL AND METHODS: Sixty eyes of 60 children with esotropia were included. The mean age was 9.5 ± 3.1 years. The choroidal thickness was measured using SD-OCT, which was performed before the surgery and 1 week, 1 month and 3 months postoperatively. At the same time, the patients' visual acuity was evaluated. RESULTS: There were no statistically significant differences between the preoperative and postoperative values in terms of the visual acuity (P > 0.05). When compared to the preoperative values, decreases were found in the choroidal thicknesses in all of the areas measured during the first week evaluation (P < 0.05). In the postoperative first month, significant decreases were also found in the choroidal thicknesses in all the areas measured (P < 0.05); however, in the postoperative third month, there were no changes in any of the areas (P > 0.05). CONCLUSIONS: We observed that there was a significant decrease in the choroidal thickness during the early postoperative period and no significant change in the late postoperative period in paediatric patients of double horizontal muscle surgery. Moreover, these early changes in the choroid in paediatric patients show that it does not cause a functional loss.

Comparison of Optical Low-Coherence Reflectometry and Swept-Source OCT-Based Biometry Devices in Dense Cataracts.

PURPOSE: To investigate agreement between biometric measurements obtained from the Lenstar LS 900 (Haag-Streit AG) based on optical low-coherence reflectometry (OLCR) and the Tomey OA-2000 (Tomey Corporation) based on swept-source optical coherence tomography (SS-OCT) in dense cataracts. METHODS: In this prospective observational study, axial length, keratometry, anterior chamber depth (ACD), lens thickness, and central corneal thickness (CCT) were measured in 124 eyes of 76 patients. Intraocular lens prediction errors and absolute prediction errors were assessed based on postoperative manifest refraction. Analyses used were paired t test, Pearson correlation coefficient (r), and Bland-Altman plots. RESULTS: Failure in axial length measurements was noted in 28 eyes (22.58%) with OCLR compared to 2 eyes (1.6%) with SS-OCT. Although not statistically significant, axial length measurements were clinically higher with SS-OCT (23.78 ± 1.76 mm) compared to OCLR (23.72 ± 1.58 mm) (P = .81) (r = 0.23; P = .01). There was a significant trend toward myopic intraocular lens prediction with SS-OCT (-0.09 ± 0.48) compared to OLCR (0.09 ± 0.41, P < .01) (r = 0.25, P = .01). There was good agreement for keratometric and ACD values between the two devices. SS-OCT gave significantly higher values of lens thickness compared to OCLR (4.44 ± 0.44 vs 4.18 ± 0.48 mm, P < .01) (r = 0.39, P < .01). CCT measured with OCLR was significantly higher than SS-OCT (525.64 ± 27.0 vs 513.21 ± 29.24 µm; P < .01) (r = 0.98, P < .01). CONCLUSIONS: One-fifth of the patients with dense cataracts failed axial length measurement on OCLR. SS-OCT gives clinically higher axial length measurements leading to more myopic intraocular lens prediction errors postoperatively. OCLR provides higher pachymetry and lower lens thickness values compared to the SS-OCT device. [J Refract Surg. 2020;36(8):557-564.].

Experience in cataract surgery assisted by femtosecond laser at Fundación Hospital Nuestra Señora de la Luz.

OBJECTIVE: To describe the transoperative results of cataract surgeries assisted by femtosecond laser. METHOD: Observational, descriptive, retrospective and cross-sectional study of 420 surgical records made with the LenSx platform from April 2015 to August 2017. The review of records was made through the internal electronic system accessing the preoperative and postoperative note. The information was collected through a database in Excel. The analysis of variables was performed by means of descriptive statistics with measures of central tendency. RESULTS: 86 files met inclusion criteria. The average age was 63 years. There was a general frequency of complications of 27.9% (24 surgeries). The most frequent complications were incomplete or impermeable corneal wound (37.5%), incomplete capsulorhexis (25%) and posterior capsule rupture (16.7%). CONCLUSIONS: The femtosecond laser technology incorporated in cataract surgery can be considered successful because of a low overall frequency of complications.

OBJETIVO: Describir las complicaciones transoperatorias de las cirugías de catarata asistidas por láser de femtosegundo. MÉTODO: Estudio observacional, descriptivo, retrospectivo y transversal de 420 expedientes de cirugías realizadas con la plataforma LenSx de abril de 2015 a agosto de 2017. La revisión de expedientes se realizó a través del sistema electrónico interno accediendo a las notas preoperatoria y posoperatoria. La información se recopiló en una base de datos Excel. Se realizó el análisis de variables por medio de estadística descriptiva con medidas de tendencia central. RESULTADOS: Cumplieron criterios de inclusión 86 expedientes. La edad promedio de los pacientes fue de 63 años. Se presentó una frecuencia general de complicaciones del 27.9% (24 cirugías). Las complicaciones que ocurrieron con mayor frecuencia fueron herida corneal incompleta o impermeable (37.5%), capsulorrexis incompleta (25%) y rotura de cápsula posterior (16.7%). CONCLUSIONES: La tecnología de láser de femtosegundo incorporada en la cirugía de catarata puede considerarse como exitosa al tener una baja frecuencia general de complicaciones.

Overhead Mounted Optical Coherence Tomography in Childhood Glaucoma Evaluation.

PRéCIS:: Overhead mounted spectral-domain optical coherence tomography (OCT) enables high-quality imaging of the optic nerve and macula in childhood glaucoma, and is particularly useful when standard tabletop OCT has failed or is not possible. PURPOSE: Tabletop OCT, integral to adult glaucoma management, can be limited in childhood glaucoma patients because of young age, poor cooperation, and/or technical challenges. To address these imaging difficulties, we determined the feasibility and quality of an overhead mounted unit in childhood glaucoma. Secondary aims included evaluation of peripapillary retinal nerve fiber layer (pRNFL), parafoveal total retinal thickness, and parafoveal ganglion cell complex (GCC) thickness. MATERIALS AND METHODS: Children and adults with a diagnosis of childhood glaucoma were imaged with an overhead mounted spectral-domain OCT as part of a prospective cross-sectional study. Participants had poor quality or unobtainable tabletop OCT and were scheduled for an examination under anesthesia and/or surgery as part of standard care. RESULTS: A total of 88 affected eyes in 60 of 65 (92.3%) enrolled patients (mean age, 5.9±5.9 y; range, 0.2 to 24.5) were successfully imaged. The mean image quality for analyzed scans was 22.9±6.0 dB (n=236 images). Mean values for pRNFL (80.5±31.0 µm; n=86), parafoveal total retinal thickness (301.10±39.9 µm; n=79), and parafoveal GCC thickness (96.0±21.6 µm; n=74) were calculated. CONCLUSIONS: Overhead mounted OCT allowed high-quality image acquisition and analysis in childhood glaucoma patients unable to be imaged with the tabletop counterpart, presenting an opportunity for improved clinical management and study of childhood glaucoma-related pathophysiology. pRNFL, parafoveal total retinal thickness, and parafoveal GCC thickness were decreased for affected eyes of children under 6 years of age compared with age-matched controls from a companion normative study.

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation.

Laser energy sealing systems have attracted much attention over the past decade given the general shift in surgical paradigm toward less invasive surgical approaches. Given this, it is paramount to have an objective method with which the quality of energy seals can be evaluated. Current methodologies used for this purpose can be problematic in the evaluation of small vessel seals. A methodology employing Doppler optical coherence tomography (DOCT) for the evaluation of energy seals is introduced. Avian chorioallantoic membrane vessels were subjected to thulium laser irradiation and were then scanned via OCT. Outcomes were classified based on several markers, predominantly the presence or absence of flow postirradiation. Vessel diameter and general morphology were also taken into consideration. Vessels were classified into four groups: seal (29%), rupture (30%), partial seal (19%), and unaffected (22%). All vessels were also evaluated visually by a trained neurovascular surgeon, and these visually classified outcomes were compared with DOCT evaluated outcomes. It was found that whether the vessel was considered sealed or not sealed was dependent on the evaluation method (p = 0.01) where visual classification resulted in 18% more seals than DOCT classification. Further, the specificity of visual classification was found to be strongly dependent on the number of partial seals (p < 0.0001). DOCT has shown to be an indispensable method for the evaluation of energy seals not only solely due to its high velocity resolution but also due to valuable microscopic morphological insight regarding the biological mechanisms responsible for energy sealing.

Appearance of cysts and capillary non perfusion areas in diabetic macular edema using two different OCTA devices.

The aim of this paper was to distinguish the appearance of cysts and non-perfusion areas (NPAs) in diabetic macular edema (DME) using two different Optical Coherence Tomography Angiography (OCTA) devices. In this study, patients underwent OCTA using the AngioVue XR Avanti Spectral Domain (SD) OCTA and the PLEX Elite 9000 Swept-Source (SS) OCTA. Foveal and extrafoveal regions of interest (ROI), defined as any area with an altered flow signal comparing to the surrounding retina, were selected in superficial and deep capillary plexus (SCP and DCP). ROI reflectivity were classified as hypo-reflective or hyper-reflective. Foveal ROI were analyzed to detect suspended scattering particles in motion (SSPiM). Thirty-seven DME eyes were included. A larger number of ROIs were found in SCP (55 vs 39) and DCP (60 vs 49) using PLEX Elite 9000 vs AngioVue. The majority of ROIs were hypo-reflective with both instruments, while slightly more hyper-reflective ROIs (grey) were detected with the PLEX Elite, more likely to be cysts. The hyporeflective ROIs could be NPAs or cysts with both devices. Moreover, PLEX Elite 9000 identified SSPiM in more foveal ROIs than the AngioVue in the SCP (p = 0.005) and in the DCP (p = 0.027). In conclusion, NPAs and cysts may show variable appearances using different OCTA devices. Hyperreflective ROIs generally correspond to cysts, hyporeflective ROIs can be either cysts or NPAs. The SS-OCTA seems to detect SSPiM more frequently than the SD-OCTA.

Otitis Media Middle Ear Effusion Identification and Characterization Using an Optical Coherence Tomography Otoscope.

OBJECTIVE: To determine the feasibility of detecting and differentiating middle ear effusions (MEEs) using an optical coherence tomography (OCT) otoscope. STUDY DESIGN: Cross-sectional study. SETTING: US tertiary care children's hospital. SUBJECTS AND METHODS: Seventy pediatric patients undergoing tympanostomy tube placement were preoperatively imaged using an OCT otoscope. A blinded reader quiz was conducted using 24 readers from 4 groups of tiered medical expertise. The primary outcome assessed was reader ability to detect presence/absence of MEE. A secondary outcome assessed was reader ability to differentiate serous vs nonserous MEE. RESULTS: OCT image data sets were analyzed from 45 of 70 total subjects. Blinded reader analysis of an OCT data subset for detection of MEE resulted in 90.6% accuracy, 90.9% sensitivity, 90.2% specificity, and intra/interreader agreement of 92.9% and 87.1%, respectively. Differentiating MEE type, reader identification of nonserous MEE had 70.8% accuracy, 53.6% sensitivity, 80.1% specificity, and intra/interreader agreement of 82.9% and 75.1%, respectively. Multivariate analysis revealed that age was the strongest predictor of OCT quality. The mean age of subjects with quality OCT was 5.01 years (n = 45), compared to 2.54 years (n = 25) in the remaining subjects imaged (P = .0028). The ability to capture quality images improved over time, from 50% to 69.4% over the study period. CONCLUSION: OCT otoscopy shows promise for facilitating accurate MEE detection. The imageability with the prototype device was affected by age, with older children being easier to image, similar to current ear diagnostic technologies.

Morpho-molecular ex vivo detection and grading of non-muscle-invasive bladder cancer using forward imaging probe based multimodal optical coherence tomography and Raman spectroscopy.

Non-muscle-invasive bladder cancer affects millions of people worldwide, resulting in significant discomfort to the patient and potential death. Today, cystoscopy is the gold standard for bladder cancer assessment, using white light endoscopy to detect tumor suspected lesion areas, followed by resection of these areas and subsequent histopathological evaluation. Not only does the pathological examination take days, but due to the invasive nature, the performed biopsy can result in significant harm to the patient. Nowadays, optical modalities, such as optical coherence tomography (OCT) and Raman spectroscopy (RS), have proven to detect cancer in real time and can provide more detailed clinical information of a lesion, e.g. its penetration depth (stage) and the differentiation of the cells (grade). In this paper, we present an ex vivo study performed with a combined piezoelectric tube-based OCT-probe and fiber optic RS-probe imaging system that allows large field-of-view imaging of bladder biopsies, using both modalities and co-registered visualization, detection and grading of cancerous bladder lesions. In the present study, 119 examined biopsies were characterized, showing that fiber-optic based OCT provides a sensitivity of 78% and a specificity of 69% for the detection of non-muscle-invasive bladder cancer, while RS, on the other hand, provides a sensitivity of 81% and a specificity of 61% for the grading of low- and high-grade tissues. Moreover, the study shows that a piezoelectric tube-based OCT probe can have significant endurance, suitable for future long-lasting in vivo applications. These results also indicate that combined OCT and RS fiber probe-based characterization offers an exciting possibility for label-free and morpho-chemical optical biopsies for bladder cancer diagnostics.

Endometrium imaging using real-time rotational optical coherence tomography imaging system: A pilot, prospective and ex-vivo study.

This study aimed to evaluate a novel real-time rotational optical coherence tomography (OCT) imaging system (OCTIS) with a fiber-optic probe to look at endometrium and to correlate the OCTIS images with standard histology. OCT could obtain real-time images resembling histological examination. With recent development of customized probes, it allows OCT to be used in the field of gynecology.This is a pilot, prospective, ex-vivo and observational study. Women underwent hysterectomy for various gynecological conditions were recruited and OCTIS images were obtained from endometrium of 15 fresh uterus specimens immediately after hysterectomy. The excised uterus was cut open and OCTIS imaging was obtained. The scanned region of endometrium was excised for histological examination and OCTIS images were precisely compared to corresponding histological images and ultrasound images. Blinded qualitative analysis on OCTIS images was performed by 2 assessors to determine inter-rating reliability on the histopathological diagnosis.Epithelium, glands, cysts, and stroma of endometrium were clearly seen by the OCTIS. Different phases of menstrual cycle of normal endometrium could be differentiated and pathological condition such as hyperplastic and dysplasic endometrium, which corresponded well with histological findings, could be identified. The inter-rater reliability between assessors on overall OCTIS endometrium and neoplastic OCTIS endometrium was moderate (Kendall τb of 0.58) and substantial (Kendall τb of 0.76), respectively.OCTIS can provide real-time, high-resolution and rotational imaging modality to view endometrial structure with high consistency with histological examination and satisfactory agreement between observers. It has a great potential to be developed in the clinical use of endometrial assessment for gynecological applications.

Optical coherence tomography through a rigid borescope applied to quantification of articular cartilage thickness in a porcine knee model.

There exists an unmet need for an optical coherence tomography (OCT) delivery scheme that is simple, robust, and applicable to general surgical applications. To deliver the beam in a narrow form factor, optical borescopes present an attractive potential solution. We present a method for enabling endoscopic delivery of OCT using a handheld rigid borescope adapted to a low-cost OCT engine. The system reduces the distal profile of the scanner, enabling application of the system in otherwise hard-to-access regions. The clinical potential of this design is demonstrated through real-time quantification of articular cartilage thickness, a primary biomarker of joint health during osteoarthritis. This platform has the potential to enable use of OCT for real-time feedback during arthroscopic surgery.

Repeatability and reproducibility of optical biometry implemented in a new optical coherence tomographer and comparison with a optical low-coherence reflectometer.

PURPOSE: To examine the repeatability and reproducibility of biometry provided by a new anterior-posterior segment spectral-domain optical coherence tomography (SD-OCT) device (Revo NX) and compare it with that provided by a validated optical low-coherence reflectometry (OLCR) biometer (Lenstar LS 900). SETTING: Hygeia Clinic, Gdansk, Poland. DESIGN: Prospective evaluation of diagnostic test. METHODS: The axial length (AL), lens thickness (LT), central corneal thickness (CCT), and anterior chamber depth (ACD) (corneal epithelium to lens) were measured in eyes of volunteers. Two skilled operators obtained 3 measurements in random order with the SD-OCT device. Repeatability was calculated for each observer, while reproducibility was assessed by a change in observer. To compare agreement between the SD-OCT device and OLCR device, the first observer took 3 measurements with both devices. RESULTS: The study evaluated 63 eyes of 63 volunteers. The mean AL measurement (+0.11 mm ± 0.02 [SD]) and mean ACD measurement (0.05 ± 0.04 mm) were significantly higher with the SD-OCT device than with the OLCR device; the CCT measurements did not differ between the devices. A very strong correlation was found for all parameters, while Bland-Altman analysis showed narrow 95% limits of agreement for AL (0.06 to 0.15 mm), ACD (-0.02 to 0.12 mm), LT (-0.23 to 0.17 mm), and CCT (-7.83 to 6.17 µm). CONCLUSIONS: The new SD-OCT device provided repeatable and reproducible AL, ACD, LT, and CCT measurements. The results with the SD-OCT device showed strong correlations with those obtained with the OLCR device. However, the AL and ACD measurements of the 2 devices cannot be considered interchangeable.

Intraoperative Optical Coherence Tomography in Vitreoretinal Surgery.

Intraoperative OCT (iOCT) is an emerging modality capable of displaying real-time OCT images to the surgeon during surgery. The use of iOCT during vitreoretinal surgery improves our understanding of the tissue alterations that occur during surgical manipulations, which may impact surgical decision-making. We review the current iOCT modalities and clinical applications of iOCT.