Effectiveness Of Optical Coherence Tomography Research Articles

How Can We Diagnose Ocular Surface Squamous Neoplasia With Optical Coherence Tomography?

We aimed to evaluate the effectiveness of optical coherence tomography (OCT) in the differential diagnosis of anterior segment diseases such as ocular surface squamous neoplasia (OSSN) and pterygium. Patients who were pre-diagnosed with either OSSN (21) or pterygium (19) between January 2020 and November 2022 were included in this retrospective study. Anterior segment photographs and anterior segment optical coherence tomography (AS-OCT) measurements were obtained from each patient. Excisional or incisional biopsy materials underwent pathological evaluation. Preoperative AS-OCT images of the patients with OSSN showed similarities with histopathological specimens. Both ocular and pathological specimens appeared to have a thicker epithelial layer with a distinct change from healthy to neoplastic epithelium. Preoperative AS-OCT images of individuals with pterygium were also comparable with histopathological samples. Both pathological and AS-OCT images of the pterygium patients showed a normal thickness epithelium and a thickened subepithelial layer under the epithelium. The mean epithelial thickness measured with AS-OCT in OSSN patients was found to be 295.3 ± 111.3 µm, while it was 80.7 ± 43.4 µm in pterygium patients. The difference was statistically significant (P<0.001). The receiver operating characteristic (ROC) curve analysis revealed a cut-off value of 97 µm for the differential diagnosis of OSSN from pterygium, with a sensitivity of 100% and specificity of 94.7%. AS-OCT can be used as a noninvasive diagnostic tool for the evaluation of ocular surface lesions. Its ability to distinguish between OSSN and pterygium is demonstrated by the statistically significant difference in epithelial thickness and the significant morphological association with histopathological findings.

The current clinical role of optical coherence tomography angiography in neuro-ophthalmological diseases.

After the revolutionary effect of optical coherence tomography (OCT) on ophthalmology practice, recent OCT-based technology OCT angiography (OCT-A) also has rapidly gained a wide clinical acceptance. OCT-A is a noninvasive, depth-resolved imaging tool for the evaluation of retinal vascular changes. Since its introduction, the understanding of retinal vascular diseases, pacychoroid spectrum diseases, and other diseases have been enriched in many ways. More importantly, OCT-A provides depth-resolved information that has never before been available. The whole spectrum of neuro-ophthalmological diseases shows consistent peripapillary and macular capillary changes with structural and functional correlation. The superficial and deeper retinal and choroidal vasculatures are affected depending on the nature of the disease process. Therefore, OCT-A play an important role in the diagnosis and management of optic nerve-related diseases as well. In this review, we summarized existing literature on the use of OCT-A in neuro-ophthalmological diseases such as arteritic anterior ischemic neuropathy, nonarteritic anterior ischemic neuropathy, papillitis, papilledema, multiple sclerosis. Currently, OCT-A has an important position as a useful, noninvasive tool in the evaluation of neuro-ophthalmologic diseases; however, OCT-A has several limitations regarding its technical capabilities in challenging neuro-ophthalmic cases. With the improvement in the technical capacity of OCT-A, it will have a more important place in the diagnosis and follow-up of neuro-ophthalmological diseases in future.

Effect of optical coherence tomography and angiography sampling rate towards diabetic retinopathy severity classification.

Optical coherence tomography (OCT) and OCT angiography (OCT-A) may benefit the screening of diabetic retinopathy (DR). This study investigated the effect of laterally subsampling OCT/OCT-A en face scans by up to a factor of 8 when using deep neural networks for automated referable DR classification. There was no significant difference in the classification performance across all evaluation metrics when subsampling up to a factor of 3, and only minimal differences up to a factor of 8. Our findings suggest that OCT/OCT-A can reduce the number of samples (and hence the acquisition time) for a volume for a given field of view on the retina that is acquired for rDR classification.

The Effects of Pyridoxine on Retinal Nerve Fiber Layer in Tuberculous Treatment

Aim: Ethambutol and isoniazid, two of the main drugs used in the treatment of tuberculosis, can lead to optic neuropathy. Optical coherence tomography (OCT) is a non-invasive, repeatable, high resolution imaging technique used in the diagnosis and follow-up of optic nerve diseases. The purpose of this study was to investigate the effect of pyridoxine added to antituberculous therapy on retinal nerve fiber layer (RNFL) thickness and the effectiveness of OCT in the early diagnosis and monitoring of optic neuropathy.Material and Methods: Twenty four patients diagnosed with pulmonary or non-pulmonary tuberculosis were included in the study. Patients divided into two groups. One group received antituberculous therapy alone, and the other group received 50 mg pyridoxine in addition to antituberculous therapy. RNFL thickness in both eyes was measured using OCT before treatment and 2-month after treatment.Results: The change in the second month of treatment according to baseline in terms of average RNFL thicknesses in the right eyes, showed a statistically significant difference between the groups using and not using pyridoxine (p=0,038). However, there was no significant difference in the left eyes in terms of RNFL thickness in any of the quadrants between the groups.Conclusion: Despite a decrease in RNFL thickness in patients receiving antituberculous therapy alone, no change in RNFL thickness occurred in patients receiving pyridoxine in addition to antituberculous therapy. We think that early ototoxicity can be detected with RNFL thickness measurement using OCT in asymptomatic patients and that the addition of pyridoxine to antituberculous therapy prevents ototoxicity.

Effect of three-dimensional reconstruction-assisted 23G micro-invasive vitrectomy in patients with proliferative diabetic retinopathy.

In the present study, we investigated the effect of optical coherence tomography (OCT) three-dimensional reconstruction-assisted 23G micro-invasive vitrectomy (abbreviated to‘23G’) in patients with proliferative diabetic retinopathy (PDR). A total of 66 PDR patients (66 eyes) were continuously selected and randomly divided into the control and observation groups with 33 patients in each group. Patients in the control group were treated with routine OCT examination while the patients in the observation group were treated with OCT three-dimensional retinal reconstruction. The 23G surgical method was applied to the two groups, and a comparison was made on the clinical effects in the two groups. The follow-up visits lasted for approximately 6 months, and it was found that the operative time, occurrence rate of intraoperative complications and postoperative complications as shown in the observation group were significantly less than those in the control group (P<0.05). The best corrected visual acuity (BCVA) was improved, the intraocular pressure was increased and retinal thickness was decreased after the treatment. The BCVA of patients in the observation group was significantly greater than that of patients in the control group while the intraocular pressure and retinal thickness of patients in the observation group were significantly less than those of patients in the control group (P<0.05). In conclusion, the effect of 23G surgical method in PDR patients can be improved and corresponding complications can be reduced under the assistance of OCT three-dimensional reconstruction.

Short wave-automated perimetry (SWAP) versus optical coherence tomography in early detection of glaucoma.

ObjectiveTo assess the role and diagnostic effectiveness of optical coherence tomography (OCT) and short wave–automated perimetry (SWAP) to distinguish between normal, glaucoma suspects, and surely diagnosed glaucomatous eye.BackgroundChanges in the optic disc and retinal nerve fiber layer (RNFL) often precede the appearance of visual field defect with standard automated perimetry. Unfortunately, RNFL defect can be difficult to identify during clinical examination. Early detection of glaucoma is still controversial, whether by OCT, SWAP, or frequency-doubling technology perimetry.Patients and methodsIn this randomized controlled, consecutive, prospective study, a total 70 subjects (140 eyes) were included in the study, divided into three groups: Group A, 10 healthy volunteers (20 eyes); Group B, 30 patients (60 eyes) with glaucoma suspect; and Group C, 30 patients (60 eyes) with already diagnosed glaucomatous eyes.ResultsAverage RNFL thickness was 75±9.0 in the glaucoma group, 99±15.5 in the control group, and 94±12 in glaucoma suspect. The inferior quadrant was the early parameter affected. There was significant correlation between visual field parameters and RNFL thickness in both glaucoma and glaucoma suspect groups.ConclusionBoth RNFL thickness measured by OCT and SWAP indices are good discrimination tools between glaucomatous, glaucoma suspect, and normal eyes. OCT parameters tend to be more sensitive than SWAP parameters.

Optical coherence tomography guidance for percutaneous coronary intervention with bioresorbable scaffolds

BackgroundThe effect of optical coherence tomography (OCT) guidance on the implantation strategy during all phases of percutaneous coronary intervention (PCI) with bioresorbable vascular scaffolds (BVSs) in a real-world scenario has been poorly investigated. MethodsConsecutive patients undergoing BVS implantation at our institution were included in this registry. Frequency-domain OCT pullbacks were performed at the operator's discretion during all phases of BVS implantation procedures to optimize preparation of lesions, confirm BVS size, and optimize expansion and apposition of scaffolds. ResultsBetween September 2012 and July 2015, 203 BVSs were implanted in 101 consecutive patients at our institution (2.01 BVSs/patient). In 66 patients, the procedure was performed under OCT guidance. In the OCT subgroup, 66 (77.6%) of the 85 treated lesions were complex (B2/C AHA/ACC type). Overall, 147 OCT pullbacks were performed and 72/147 (49.0%) pullbacks indicated the need for changing strategy. After angiography-only-guided optimisation of BVS in 27 (31.8%) lesions, an OCT examination prompted performance of a second post-expansion. This resulted in an increase in the minimal scaffold area (5.5 to 6.3mm2, p=0.004) and a decrease in the incomplete scaffold apposition area (1.1 to 0.6mm2, p=0.082), with no new stent fractures. When the population was divided according to the time of BVS implantation, an initial learning adaptation became evident, with the number of OCT-guided changes in strategy significantly decreasing between the initial and final time periods (p=0.017). ConclusionsOCT guidance for BVS implantation significantly affects the procedural strategy, with favourable effects on acute results and the learning curve.

The effectiveness of optical coherence tomography for evaluating peri-implant tissue: A pilot study.

PurposeOptical coherence tomography (OCT) has been investigated as a novel diagnostic imaging tool. The utilisation of this equipment has been evaluated through several studies in the field of dentistry. The aim of this preliminary study was to determine through basic experiments the effectiveness of OCT in implant dentistry.Materials and MethodsTo assess detection ability, we captured OCT images of implants in each of the following situations: (1) implants covered with mucosae of various thicknesses that were harvested from the mandibles of pigs; (2) implants installed in the mandibles of pigs; and (3) implants with abutments and crowns fixed with temporary cement. The OCT images were captured before cementation, after cementation, and after removing the excess submucosal cement.ResultsIf the thickness of the mucosa covering the implant body was less than 1 mm, the images of the implants were clearly detected by OCT. In the implants were installed in pigs' mandibles, it was difficult to capture clear images of the implant and alveolar bone in most of the samples. Remnants of excess cement around the implants were visible in most samples that had a mucosa thickness of less than 3 mm.ConclusionCurrently, OCT imaging of implants is limited. Cement remnants at the submucosal area can be detected in some cases, which can be helpful in preventing peri-implant diseases. Still, though there are some restrictions to its application, OCT could have potential as an effective diagnostic instrument in the field of implant dentistry as well.

Effect of Grid Decentration on Macular Thickness Measurements in Normal Subjects and Patients with Diabetic Macular Edema

To evaluate the effect of optical coherence tomography (OCT) grid decentration on macular thickness measurements in healthy subjects and patients with diabetic macular edema. In this prospective study, 3D spectral-domain OCT images of 51 eyes with clinically significant diabetic macular edema and 29 healthy eyes were assessed. In each eye, the macular Early Treatment Diabetic Retinopathy Study grid was evaluated for decentration. After grid adjustment, changes in central subfield thickness (CST) and central subfield volume (CSV) measurements were recorded. Changes &gt;1 μm and &gt;8.5 μm in CST were considered as grid decentration and clinically significant grid decentration, respectively. Grid decentration was found in 10 normal eyes (34.6%) and 32 clinically significant macular edema (CSME) eyes (62.7%, p = 0.01). Clinically significant CST changes were found in 3 normal eyes (10.3%) and 23 CSME eyes (45%, p = 0.001). The mean change in CST after grid adjustment was 6.4 ± 5.8 µm and 24.7 ± 27 µm in normal and CSME eyes (p = 0.04). Age, sex, and CST had no statistically significant effect on grid decentration in normal and CSME eyes. Best-corrected visual acuity was significantly worse in eyes with grid decentration (0.75 ± 0.55 vs 0.42 ± 0.22 logMAR, p = 0.02) and clinically significant grid decentration (0.81 ± 0.6 vs 0.45 ± 0.27 logMAR, p = 0.01). Change in CSV was detected in 3 normal eyes (10.3%) and 24 CSME eyes (47%, p = 0.001). Grid decentration occurs in a large number of OCT thickness maps and leads to significant error in macular thickness measurements. The effect is more prominent in patients with CSME.

Impact of scanning density on spectral domain optical coherence tomography assessments in neovascular age‐related macular degeneration

To determine the effect of optical coherence tomography (OCT) B-scan density on the qualitative assessment of neovascular age-related macular degeneration (AMD). Data were collected from 59 patients imaged with Topcon 3D OCT-1000 (128 B-scans × 512 A-scans). Custom software was used to generate less dense subsets of scans: 1/16 (eight B-scans), 1/8 (16 B-scans), 1/4 (32 B-scans) and 1/2 (64 B-scans). At each B-scan density, scans were assessed for cystoid spaces, subretinal fluid (SRF), subretinal tissue (SRT) and pigment epithelium detachment (PED). For each sampling density, sensitivity, specificity and predictive values were calculated using the full volume scan (128 B-scans) as the reference standard. For cystoid spaces, the detection sensitivity was 76.3% at 1/16 density; this rose to 89.5% with a 1/4 density. For SRF, the detection sensitivity was 75.0% at a 1/16 density; this increased to 91.1% with 1/4 density. For PED, even at the lowest sampling density (1/16) the detection sensitivity was 86.4%; this rose to 94.9% at 1/4 density. For SRT, detection sensitivity at a 1/16 density was 64.7% and only rose above 90% with the densest sampling subset (1/2). Use of scanning protocols with reduced sampling densities resulted in decreased detection of key features of neovascular AMD; despite this, a sampling density reduced to 1/4 appeared to allow accurate assessment for most features. Current management of neovascular AMD is dependent on qualitative assessment of OCT images; with the recent proliferation of OCT systems, optimization and standardization of scanning protocols may be of value.

Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study

To study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models. Forty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1 to 2.5 mm). The RNFL profile in each eye was constructed with a mathematical model using a smoothing spline approximation. Scan circle (diameter 3.4 mm) RNFL measurements (total average, superior, nasal, inferior, and temporal RNFL thicknesses) obtained from eight directions (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, and superotemporal) displaced at different distances (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 mm) from the disc centre were then computed by a computer program and compared to the 'reference standard' where the scan circle is centred at the optic disc. RNFL measurement error was calculated as the absolute of (RNFL thickness(displaced) - RNFL thickness(reference standard)). The respective mean average, superior, nasal, inferior, and temporal RNFL measurement errors were 2.3+/-2.0, 4.9+/-4.5, 4.1+/-3.8, 6.2+/-7.6, and 3.8+/-3.5 microm upon 0.1 mm scan circle displacement, and 12.1+/-11.4, 27.8+/-18.4, 21.7+/-18.6, 34.8+/-22.9, and 15.2+/-10.7 microm upon 0.7 mm scan circle displacement. Significant differences of average and quadrant RNFL thicknesses were evident between centred and displaced scan circle measurements (all with P<0.001). RNFL measurement error increased in a monotonic fashion with increasing distance away from the disc and the change was direction-dependent. RNFL measurement error varies with the direction and distance of scan displacement. The superior and the inferior RNFL measurements are most vulnerable to scan displacement errors, whereas the average RNFL thickness is the least susceptible. Obtaining a well-centred scan is essential for reliable RNFL measurement in OCT.

Identification of visually significant operculum without macular hole by optical coherence tomography

Case report: We report a case that illustrates the effectiveness of optical coherence tomography (OCT) in identifying visually significant vitreoretinal interface opacities in the absence of a macular hole. A patient presented with a scotoma in the right eye. Fundoscopic examination revealed a small lesion in close proximity to the foveal avascular zone. OCT of the right eye revealed a small operculum in the vitreous anterior to the fovea without evidence of a macular hole. Comments: To our knowledge, ours is the first reported case of the use of OCT to identify the presence of a visually significant operculum without an associated macular hole.

(Cost)-Effectiveness of Optical Coherence Tomography (OCT) in Basal Cell Carcinoma (BCC)

(Cost)-Effectiveness of Optical Coherence Tomography (OCT) in Basal Cell Carcinoma (BCC)