This paper presents signal processing aspects for automatic segmentation of retinal layers of the human eye. The paper draws attention to the problems that occur during the computer image processing ...of images obtained with the use of the Spectral Domain Optical Coherence Tomography (SD OCT). Accuracy of the retinal layer segmentation for a set of typical 3D scans with a rather low quality was shown. Some possible ways to improve quality of the final results are pointed out. The experimental studies were performed using the so-called B-scans obtained with the OCT Copernicus HR device.
The aim of this study was the assessment of the relationship between cigarette smoking and optic nerve and macular vessel density measured by optical coherence tomography angiography. We examined 30 ...eyes from 30 healthy habitual smokers. The examination was performed using a high-speed and high-resolution spectral-domain optical coherence tomography RTVue XR Avanti with AngioVue (Optovue, Fremont, CA, USA) with a split-spectrum amplitude-decorrelation angiography algorithm. Blood pressure, heart rate, vascular density in the area of the optic nerve head (4.5*4.5 mm) and vascular density with the foveal avascular zone in the central macula (3.0*3.0 mm) were measured and analyzed before, immediately after and 30 minutes after cigarette smoking. Quantitative measurements were carried out by AngioAnalytics Phase 7 software. Immediately after smoking both heart rate and blood pressure increased significantly (p < 0.001) compared to values before smoking and then significantly decreased after 30 minutes comparing to values obtained right after smoking (p < 0.001). The mean area of the foveal avascular zone, parafoveal vessel density, and peripapillary vessel density did not change significantly. Our results show no immediate influence of smoking on vessel density parameters measured by specific OCTA machine in healthy habitual smokers.
In this paper methods and their examination results for automatic segmentation and parameterization of vessels based on spectral domain optical coherence tomography (SD-OCT) of the retina are ...presented. We present three strategies for morphologic image processing of a fundus image reconstructed from OCT scans. A specificity of initial image processing for fundus reconstruction is analysed. Then, the parameterization step is performed based on the vessels segmented with the proposed algorithm. The influence of various methods on the vessel segmentation and fully automatic vessel measurement is analysed. Experiments were carried out with a set of 3D OCT scans obtained from 24 eyes (12 healthy volunteers) with the use of an Avanti RTvue OCT device. The results of automatic vessel segmentation were numerically compared with those prepared manually by the medical doctor experts.
We describe an alternative vitreoretinal technique that allows for the macular hole closure without filling the vitreous cavity with gas.
A prospective interventional one-center case series from ...March 2019 to January 2020. The patients underwent the formation of viscoelastic-assisted temporal internal limiting membrane flap without any gas endotamponade. Preoperative and postoperative visual acuity and foveal structure in optical coherence tomography images were evaluated.
Macular hole closure was achieved with a single procedure in 11 of 12 eyes with no endotamponade application. Preoperative, mean best-corrected visual acuity was 1.11 (Snellen equivalent 20/258) ± 0.28 logarithm of the minimal angle of resolution (range 1.398-0.523). We were able to assess visual acuity as early as on the first postoperative day in all patients. It ranged from 1.398 to 0.523 logarithm of the minimal angle of resolution (Snellen equivalent 20/500-20/67) with a mean of 0.97 (20/186) ± 0.29. Final best-corrected visual acuity was 0.31 (Snellen equivalent 20/40) ± 0.18 (range 0.699-0.1) at the end of the 3-month follow-up.
This technique avoids the application of any tamponade, does not require positioning, and seems to provide macular hole closure rates similar to those of traditional vitrectomy with gas.
To evaluate a new method for volumetric imaging of the preretinal space (also known as the subhyaloid, subcortical, or retrocortical space) and investigate differences in preretinal space volume in ...vitreomacular adhesion (VMA) and vitreomacular traction (VMT).
Nine patients with VMA and 13 with VMT were prospectively evaluated. Automatic inner limiting membrane line segmentation, which exploits graph search theory implementation, and posterior cortical vitreous line segmentation were performed on 141 horizontal spectral domain optical coherence tomography B-scans per patient. Vertical distances (depths) between the posterior cortical vitreous and inner limiting membrane lines were calculated for each optical coherence tomography B-scan acquired. The derived distances were merged and visualized as a color depth map that represented the preretinal space between the posterior surface of the hyaloid and the anterior surface of the retina. The early treatment d retinopathy study macular map was overlaid onto final virtual maps, and preretinal space volumes were calculated for each early treatment diabetic retinopathy study map sector.
Volumetric maps representing preretinal space volumes were created for each patient in the VMA and VMT groups. Preretinal space volumes were larger in all early treatment diabetic retinopathy study map macular regions in the VMT group compared with those in the VMA group. The differences reached statistical significance in all early treatment diabetic retinopathy study sectors, except for the superior outer macula and temporal outer macula where significance values were P = 0.05 and P = 0.08, respectively. Overall, the relative differences in preretinal space volumes between the VMT and VMA groups varied from 2.7 to 4.3 in inner regions and 1.8 to 2.9 in outer regions.
Our study provides evidence of significant differences in preretinal space volume between eyes with VMA and those with VMT. This may be useful not only in the investigation of preretinal space properties in VMA and VMT, but also in other conditions, such as age-related macular degeneration, diabetic retinopathy, and central retinal vein occlusion.
We investigated characteristics and treatment outcomes of pediatric vs adult retinal detachment managed by retinotomy and retinectomy.
This was a retrospective, nonrandomized, interventional study ...involving 20 pediatric patients and 25 adult patients operated with vitrectomy and retinectomy due to retinal detachment. Outcome measures included preoperative and postoperative visual acuity at 6 months and at final visit, postoperative proliferative vitreoretinopathy, silicone oil removal, final intraocular pressure (IOP), and final anatomic success, defined as complete retinal reattachment.
Reattachment was observed in 60% (12/20) of pediatric patients and 88% (22/25) of adults at final visit (p=0.041). Statistically significant improvement in visual acuity was observed in adults (p<0.001) but not in children (p=0.360) due to large proportion of anatomic failure. Children required a higher number of further reoperations (p=0.008). Postoperative proliferative vitreoretinopathy was significantly more frequent in pediatric eyes (p=0.003).
The clinical features and prognosis for pediatric retinotomies and retinectomies are different from those for adults. When a decision to perform retinotomy in children is made, we can anticipate significantly lower anatomic success than in adults. Even though the overall visual acuity was worse in children than in adults, 25% of pediatric eyes achieved 5/50 or better vision.
The aim of the study is to report a technique of a pedicled autologous choroid retinal pigment epithelium (RPE) patch that aims to preserve perfusion of the transplanted tissue. A case report of a ...patient with sudden vision deterioration due to submacular hemorrhage in age-related macular degeneration. The surgery involved a 180-degree peripheral retinectomy and the creation of a pedicled graft instead of an isolated one. Outcome measures included preoperative and postoperative visual acuity and optical coherence tomography scans at 1, 3, 6, 12 months and patch vascularization on postoperative indocyanine green angiography. Postoperatively the patch was positioned under the fovea with an intact pedicle. Indocyanine green angiography showed perfusion through the pedicle and patch vasculature on the third postoperative day. Best corrected visual acuity improved from 0.5/50 to 5/50 at 1 month and remained stable over 1 year follow-up. No choroidal neovascularization recurrence was observed. This case report demonstrates the feasibility of a pedicled RPE-choroid graft that is an alternative to a free isolated graft. Our modification of patch surgery, by demonstrating early perfusion, offers an advantage, similar to macular translocation, when photoreceptors are embedded in RPE and choroid with blood circulation immediately after the surgery.
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