Optic Disc Diameter Research Articles

Optic disc morphometry using spectral domain optical coherence tomography in a Nigerian population.

To assess morphological optic disc dimensions using spectral-domain optical coherence tomography (OCT) in a Nigerian population. Good quality SD-OCT scans of the optic disc of 147 eyes of 88 participants were selected, enrolled, and retrospectively reviewed. All subjects had optic nerve head and retinal nerve fibre layer OCT imaging, as well as analysis, done using the Topcon 3D OCT-1 Maestro®. The age, sex, and some OCT-generated optic disc dimensions namely disc area (DA), vertical disc diameter (VDD), horizontal disc diameter (HDD) were retrieved from the database and analyzed. The mean age of the study subjects was 52.6±20.9 years with a range of 8-90 years; male to female ratio was 1:1.3. The right eye and left eye accounted for 75 and 72 of the 147 scans respectively. The mean DA, VDD, and HDD were 2.54 ± 0.48 mm2, 1926.5 ± 189.6 μm and 1673.9 ± 173.9 μm, respectively. Males had significantly larger DA than females (2.56 ± 0.53 mm2 vs 2.51 ± 0.44 mm2, p = 0.043). The mean DA and VDD of eyes of subjects aged 21-40 years were significantly higher compared to subjects aged 60 years and more (p = 0.008 and 0.001, respectively). The mean optic disc area and diameters are larger than those reported in similar studies involving blacks and other races. The mean disc area reduces with increasing age.

Determining the Location of the Fovea Centralis Via En-Face SLO and Cross-Sectional OCT Imaging in Patients Without Retinal Pathology.

PurposeThe purpose was to establish the position of the fovea centralis to the optic nerve via en-face, near-infrared spectral domain optical coherence tomography (NIR-OCT) in healthy patients. This may shed light on physiological variability and be used for studying subtle cases of foveal ectopia in macular pathology and after retinal detachment.MethodsSD-OCT data of 890 healthy eyes were retrospectively analyzed. Exclusion criteria included axial myopia causing tilting of the optic disc, peripapillary atrophy >1/3 the width of the disc, macular images excluding greater than half of the optic disc, and patients unable to maintain vertical head positioning. Two independent reviewers measured the horizontal and vertical distance from the fovea to the optic disc center and optic disc diameter via cross-sectional and en-face scanning laser ophthalmoloscopy OCT imaging.Results890 eyes were included in the study. The right and left eyes differed in the horizontal distance from the fovea to the disc center (4359 vs. 4248 µm, P < 0.001) and vertical distance from the fovea to the disc center (464 µm vs. 647, P < 0.001). This corresponded to a smaller angle between the right and left eyes (6.07° vs. 8.67°, P < 0.001). Older age was associated with a larger horizontal (P = 0.008) and vertical distance (0.025). These differences persisted after correcting for axial length in the 487 patients with axial-length data.ConclusionsThis study compares the position of the fovea centralis among individuals without macular pathology on a micron level basis. The significant variability between right and left eyes indicates that contralateral eye evaluation cannot be reliably used. Rather, true foveal ectopia requires assessments of preoperative and postoperative NIR-OCT scans. This finding is relevant to retinal detachment cases and evaluation of subtle foveal ectopia.Translational RelevanceThis finding is relevant to retinal detachment cases and evaluation of subtle foveal ectopia.

The Natural History of Bruch’s Membrane Calcification in Pseudoxanthoma Elasticum

PurposeTo describe the natural history of Bruch’s membrane (BM) calcification in patients with pseudoxanthoma elasticum (PXE).DesignRetrospective cohort study.ParticipantsBoth eyes of 120 PXE patients younger than 50 years, 78 of whom had follow-up imaging after more than 1 year.MethodsAll patients underwent multimodal imaging, including color fundus photography, near-infrared reflectance (NIR) imaging, and late phase indocyanine green angiography (ICGA). We determined the distance from the optic disc to the central and temporal border of peau d’orange on NIR, expressed in horizontal optic disc diameter (ODD). The length of the longest angioid streak was classified into 5 zones.Main Outcome MeasuresAge-specific changes of peau d’orange, angioid streaks, and ICGA hypofluorescence as surrogate markers for the extent of BM calcification.ResultsIn cross-sectional analysis, longer angioid streaks were associated with increasing age (P < 0.001 for trend). The temporal border of peau d’orange showed a weak association with increasing age (β = 0.02; 95% confidence interval [CI], 0.00–0.04), whereas the central border showed a strong association (β = 0.12; 95% CI, 0.09–0.15). Longitudinal analysis revealed a median shift of the central border to the periphery of 0.08 ODD per year (interquartile range [IQR], 0.00–0.17; P < 0.001). This shift was more pronounced in patients younger than 20 years (0.12 ODD per year [IQR, 0.08–0.28]) than in patients older than 40 years (0.07 ODD per year [IQR, –0.05 to 0.15]). The temporal border did not shift during follow-up (P = 0.69). New or growing angioid streaks were detected in 39 of 156 eyes (25%). The hypofluorescent area on ICGA was visible only in the fourth or fifth decade and correlated with longer angioid streaks.ConclusionsIn PXE patients, the speckled BM calcification slowly confluences during life. The location of the temporal border of peau d’orange remains rather constant, whereas the central border shifts to the periphery. This suggests the presence of a predetermined area for BM calcification. A larger ICGA hypofluorescent area correlates with older age and longer angioid streaks, which implies that it depends on the degree of BM calcification.

Management of a Submacular Hemorrhage Secondary to Age-Related Macular Degeneration: A Comparison of Three Treatment Modalities.

This paper aims to compare the effects of three treatment modalities for a submacular hemorrhage (SMH) secondary to exudative age-related macular degeneration (AMD). Seventy-seven patients with an SMH were divided into three groups: small-sized (optic disc diameter (ODD) ≥ 1 to < 4), medium-sized (ODD ≥ 4 within the temporal arcade) and large-sized (ODD ≥ 4, exceeding the temporal arcade). Patients received anti-vascular endothelial growth factor (anti-VEGF) monotherapy, pneumatic displacement (PD) with anti-VEGF or a vitrectomy with a subretinal tissue plasminogen activator (tPA) and gas tamponade based on the surgeon’s discretion. The functional and anatomical outcomes were evaluated. Among the 77 eyes, 45 eyes had a small-sized, 21 eyes had a medium-sized and 11 eyes had a large-sized SMH. In the small-sized group, all treatment modalities showed a gradual best-corrected visual acuity (BCVA) improvement with high hemorrhagic regression or displacement rates (over 75%). In the medium-sized group, PD and surgery were associated with better BCVA with more displacement than anti-VEGF monotherapy (67% and 83%, respectively, vs. 33%). In the large-sized group, surgery showed a better visual improvement with a higher displacement rate than PD (86% vs. 25%). Our findings demonstrated that visual improvement can be expected through appropriate treatment strategy regardless of the SMH size. In cases with a larger SMH, invasive techniques including PD or surgery were more advantageous than anti-VEGF monotherapy.

Association between morphological characteristics of the optic disc and other anatomical features of the fundus in highly myopic eyes

To investigate associated factors with optic disc characteristics in high myopia patients. According to the meta-analysis of pathologic myopia study, patients were divided into groups from categories 1 (C1) to C4. The diameters, tilt ratio, and rotation degree of optic disc, and the diameters of parapapillary atrophy were measured among other morphometric variables. Totally 147 eyes (84 patients) were included. Longer horizontal optic disc diameter was associated with smaller tilt ratio (p < 0.001, unstandardized regression coefficient B: -0.59), greater rotation degree (p < 0.001, B: 0.01), and longer horizontal delta zone diameter (p < 0.001, B: 0.09). Longer vertical optic disc diameter was associated with smaller rotation degree (p < 0.001, B: 0.01), longer vertical delta zone diameter (p < 0.001, B: 0.16), and longer disc-fovea distance (DFD; p < 0.024, B: 0.14). Generally, the horizontal optic disc diameter of C3 and C4 groups was smaller than C1 and C2, while vertical diameter and tilt ratio was greater than in C1 and C2. After setting axial length (AL) as an independent variable, horizontal diameters and tilt ratio still showed significant differences, while vertical diameters did not show significant differences. Axial elongation was associated with an increase of vertical optic disc diameter that was correlated with an reduction of optic disc rotation degree. By contrast, horizontal optic disc diameter elongation was correlated with an reduction of optic disc tilt ratio and an increase of optic disc rotation degree, which was independent of axial elongation.

Differentiation of Nonarteritic Anterior Ischemic Optic Neuropathy from Normal Tension Glaucoma by Comparison of the Lamina Cribrosa.

PurposeTo compare lamina cribrosa (LC) morphology between eyes with nonarteritic anterior ischemic optic neuropathy (NAION) and eyes with normal tension glaucoma (NTG) in the Korean population.MethodsThis retrospective study included 48 eyes with NAION, 48 eyes with NTG, and 48 healthy control eyes matched by age, intraocular pressure, axial length, and optic disc area. Eyes with NAION and NTG were also matched by retinal nerve fiber layer (RNFL) thickness in the affected sector. Optic nerve heads were scanned using enhanced depth imaging spectral-domain optical coherence tomography. LC depth (LCD) and the LC curvature index (LCCI) were measured at seven locations spaced equidistantly across the vertical optic disc diameter. LCD and the LCCI were compared in the three groups.ResultsRNFL thicknesses of the matched affected sectors did not differ between the NAION and NTG groups (P = 0.347). LCD and the LCCI were significantly larger in the NTG group than in the NAION and healthy control groups at all seven planes (P < 0.001 each), but were comparable in the NAION and healthy control groups. The LCCI was larger in the affected than in the unaffected sector of NTG eyes (P = 0.010) but did not differ in NAION eyes (P = 1.000). LCD did not differ between affected and unaffected sectors in either NAION (P = 0.600) or NTG (P = 0.098) eyes.ConclusionsLC morphology differed in eyes with NAION and NTG, despite a similar degree of RNFL damage. Evaluation of LC morphology may help to understand the distinctive pathophysiology of NAION and to differentiate NAION from NTG eyes.

Lamina Cribrosa Moves Anteriorly After Trabeculectomy in Myopic Eyes.

PurposeThe purpose of this study was to investigate changes in lamina cribrosa (LC) depth after trabeculectomy in myopic eyes using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD-OCT).MethodsSerial horizontal B-scans of the optic nerve head of 41 myopic eyes with primary open-angle glaucoma (POAG) were obtained before and 3 months after trabeculectomy using EDI SD-OCT. LC depth, defined as the distance from the opening plane of Bruch's membrane to the level of the anterior LC surface, was measured before and 3 months after trabeculectomy at 7 locations spaced equidistantly across the vertical optic disc diameter on B-scan images. The mean of the measurements at these seven planes was defined as the average LC depth. Factors associated with changes in LC depth were identified by linear regression.ResultsIntraocular pressure (IOP) decreased from 26.3 ± 9.3 millimeters of mercury (mm Hg) preoperatively to 10.6 ± 3.5 mm Hg 3 months after trabeculectomy. LC depth was significantly lower 3 months after trabeculectomy than preoperatively (P < 0.001, all planes). The magnitude of LC depth reduction was significantly associated with younger age, higher preoperative LC depth, and greater magnitude of IOP reduction (all P ≤ 0.016).ConclusionsLC depth reduction was observed after trabeculectomy in myopic eyes. The degree of LC depth reduction was not related to the degree of myopia.

Automated macula proximity diagnosis for early finding of diabetic macular edema

Diabetic retinopathy (DR) is non-recoverable in nature. One of the advanced sight threatening condition in diabetic patient is defined in terms of diabetic macular edema (DME), where the macula gets deposited with fluid rich in proteins called exudates. It is indisputably required to find and treat occurrence of exudates near macula in time, to avoid further complications of retina and vision loss at later stage. However, presence of various dark and bright lesions awakes the need of reliable macula and exudate detection process. Proposed work intends to present a robust, scale, and rotation invariant tool for early diagnosis of DME. Optic disc (OD) diameter is one of the important parameters; it is always proportional to the size of the retina; an adaptive method based on pixel count and histogram-based segmentation is used for optic disc detection. Center of macula is detected based on estimated optic disc radius calculations and anatomical priors. In order to reduce computational burden, two disc diameter (DD) region near macula is extracted. Hard exudates are extracted with unique combination of CLAHE and morphological operations, followed by Kirsch’s mask for sharp edge detection of hard exudates, and further morphological operations for noise removal. OD detection algorithm is evaluated on four different databases DiaretDB1, MESSIDOR, DRIONS-DB, and images from local hospital, overall sensitivity of 95.71% is achieved, highest sensitivity value is 98%, and is achieved on first 100 images from MESSIDOR database. Further DiaretDB1 and images from local hospital are processed further for macula detection and exudates finding in macular proximity, as DiaretDB1 is rich in variety of DR lesions and images from the local hospital to deal with real-time issues. Finding macula region is achieved with an overall success rate of 91.93% and overall sensitivity of 99% is reported on both the chosen databases. Proposed work provides an automated tool, for early diagnosis of diabetic macular edema. The method is straightforward, robust and computationally less complex and improved success rates for feature, and lesion detections are achieved as compared with state-of-the-art methods.

A randomized clinical trial comparing prompt photodynamic therapy with 3 months observation in patients with acute central serous chorioretinopathy with central macular leakage.

The purpose of the study was to demonstrate whether photodynamic therapy in patients with acute central serous chorioretinopathy, with the leakage point within one optic disk diameter from the fovea, can be safely deferred. A single-center, randomized, controlled trial was conducted. Patients were randomized to photodynamic therapy within a week after presentation (Group I, 26 patients) or observation during 3 months (Group II, 26 patients). If leakage or subretinal fluid was observed during any control visit, photodynamic therapy was performed (again) within a week. Primary outcome was change of visual acuity (Early Treatment Diabetic Retinopathy Study) after 12 months. Secondary outcomes were visual acuity, central foveal thickness, metamorphopsia, and color discrimination. Photodynamic therapy procedures: group I, 26 at baseline, 2 retreatments at 3 months; group II, 10 at 3 months, 1 at 6 months (2 subjects refusing treatment), 2 retreatments at 6 months. At 12 months, mean visual acuity of all patients had improved by 6.5 letters (P < 0.001), mean central foveal thickness was 172 µm less (P < 0.001). After photodynamic therapy, visual acuity recovered faster and metamorphopsia significantly improved (3 months, P < 0.001). Differences between groups at 12 months were not significant. The (intended) number of photodynamic therapy (re)treatments in group II (n = 15) was 46% less than in group I (n = 28). Visual acuity and central foveal thickness at 12 months were similar. Therefore, the preferred management of acute central serous chorioretinopathy at presentation appears to be observation for 3 months.

&lt;p&gt;Risk of Recurrence and Transition to Chronic Disease in Acute Central Serous Chorioretinopathy&lt;/p&gt;

PurposeTo study the risk of recurrence in acute central serous chorioretinopathy (aCSC) and to evaluate the risk of transitioning to chronic CSC.Patients and MethodsThe medical records and multimodal imaging data of 295 aCSC cases were reviewed. Typical aCSC was defined as the presence of serous subretinal fluid (SRF), one focal leakage spot on fluorescein angiography (FA), retinal pigment epithelium (RPE) alterations limited in area to less than one optic disc diameter, and complete recovery from this first CSC episode. An increase in RPE alterations combined with persistent SRF was considered a sign of chronicity, which was determined in cases with >12 months follow-up. The main outcome measures included final visual acuity, percentage of disease recurrence, and percentage of cases moving toward a chronic phenotype. Treatment strategies and their efficacy were also reviewed.ResultsA total of 295 eyes in 291 patients with aCSC were included. Spontaneous recovery was awaited in 154 eyes (52%), whereas 141 eyes (48%) recovered following treatment. SRF recurrence occurred in 24% of untreated cases and in 4% of treated cases (p<0.001). An analysis of 61 eyes that underwent an FA after ≥12 months of follow-up revealed increased RPE alterations in 22 eyes (36%), and 14 eyes (23%) had both an increase in RPE alterations and SRF recurrence.ConclusionAll aCSC cases recovered from the first disease episode, and none of the cases developed persistent SRF leakage. Among the cases for which long-term follow-up information was available, 36% showed a tendency toward chronicity in terms of increased RPE alterations, whereas 23% showed both an increase in RPE alterations and recurrent SRF. Early photodynamic therapy (PDT) may decrease the risk of recurrences.

Analysis of Retinal Vessel Pulsations with Electrocardiographic Gating.

The origin of retinal venous pulsations has been a matter of debate for some time. One classical explanation to the origin of these pulsations has been that the cardiac cycle induces systolic peaks in the intraocular pressure (IOP) which leads to decreases in retinal vein diameters. Recently, theoretical concepts have been published which postulate that IOP changes during the pulse cycle is not the primary driving force for venous pulsation, and hence, predict that the retinal vein diameter is indeed reduced during IOP diastole. The aim of the study was to test this hypothesis in a clinical trial. Continuous IOP and retinal vessel analyser (RVA) measurements were taken from 21 subjects, ages 20 to 30 years, with no known ophthalmologic diseases, while connected to a standard electrocardiograph (ECG). With this methodology, average and synchronised curves for the pulse cycle of IOP and retinal vessel pulsations were calculated for each subject. Each pulse cycle was standardised to 50 timepoints, which enabled direct phase shift comparisons. All subjects showed comparable results. Close to the optic disc (within 0 to 1.5 optic disc diameters away from the disc), retinal arteries led with the first peak at the 16/50 pulse cycle position, followed by IOP peak at the 23/50 cycle position, and then by veins at the 26/50 cycle position. The present method indeed shows that retinal veins do not collapse when the IOP is highest, on the contrary, IOP and retinal vein diameters seem to be in phase, which lends support to the hypothesis that IOP is not the major driving force of the retinal vein pulsations.

Photovoltaic Restoration of Central Vision in Atrophic Age-Related Macular Degeneration

Loss of photoreceptors in atrophic age-related macular degeneration results in severe visual impairment, although some peripheral vision is retained. To restore central vision without compromising the residual peripheral field, we developed a wireless photovoltaic retinal implant (PRIMA; Pixium Vision, Paris, France) in which pixels convert images projected from video glasses using near-infrared light into electric current to stimulate the nearby inner retinal neurons. We carried out a first-in-human clinical trial to test the safety and efficacy of the prosthesis in patients with geographic atrophy (ClinicalTrials.gov identifier, NCT03333954). Five patients with geographic atrophy zone of at least 3 optic disc diameters, no foveal light perception, and best-corrected visual acuity of 20/400 to 20/1000 in the worse-seeing study eye. The 2-mm wide, 30-μm thick chip, containing 378 pixels (each 100 μm in diameter), was implanted subretinally in the area of atrophy (absolute scotoma). Anatomic outcomes were assessed with fundus photography and OCT for up to 12 months of follow-up. Prosthetic vision was assessed by mapping light perception, bar orientation, letter recognition, and Landolt C acuity. In all patients, the prosthesis was implanted successfully under the macula, although in 2 patients, it was implanted in unintended locations: within the choroid and off center by 2 mm. All 5 patients could perceive white-yellow prosthetic visual patterns with adjustable brightness in the previous scotomata. The 3 with optimal placement of the implant demonstrated prosthetic acuity of 20/460 to 20/550, and the patient with the off-center implant demonstrated 20/800 acuity. Residual natural acuity did not decrease after implantation in any patient. Implantation of the PRIMA did not decrease the residual natural acuity, and it restored visual sensitivity in the former scotoma in each of the 5 patients. In 3 patients with the proper placement of the chip, prosthetic visual acuity was only 10% to 30% less than the level expected from the pixel pitch (20/420). Therefore, the use of optical or electronic magnification in the glasses as well as smaller pixels in future implants may improve visual acuity even further.

Magnetic resonance imaging evaluation of retro-bulbar optic nerve in patients with optic disc pit maculopathy

Background: Optic disc pit (ODP) is a congenital anomaly characterized by indented area of the optic nerve head most likely originating from the incomplete closure of the superior edge of the embryonic fissure. Maculopathy can occasionally complicate this anomaly as intra-retinal and sub-retinal fluid at the macula. In result, maculopathy is associated with a poor visual prognosis due to a serous macular detachment, formation of macular hole, or atrophy of the retinal pigmented epithelium. In this case series, we report of three patients with unilateral ODP. Case report: We attempted to analyze the morphologic changes seen in the ODP and evaluate patients with a complete ophthalmologic evaluation, fundus color photography, spectral-domain optical coherence tomography (SD-OCT) scanning, and magnetic resonance imaging (MRI) of globe and orbit. Magnetic resonance imaging scan was done for optic disc diameter (ODD) and optic nerve sheath diameter (ONSD). Conclusion: We noticed that in the patient who presented with neurosensory detachment in the macula, the ONSD is larger than in the fellow eye and is larger than the remaining two patients with ODP and without neurosensory detachment of the retina.

The Effects of the Amount of Fluid Used in Epiduroscopic Laser Neural Discectomy Procedures on Intraocular Pressure and an Evaluation of the Ocular Findings.

During epiduroscopic laser neural discectomy (ELNP) procedures, the amount of fluid used in the epidural area may cause increased intracranial pressure. This study aimed to investigate the effect of increased epidural pressure on intraocular pressure and other ocular findings due to the amount of fluid delivered to the epidural area and the rate of delivery of the fluid. After obtaining approval from the Ethics Committee of Sakarya University Faculty of Medicine, patients who underwent ELNP in the Department of Anesthesiology and Reanimation Department, Algology Clinic, between January 2017 and May 2017 were included in this retrospective study. To evaluate the ocular findings after the operation, measurements obtained using an optical coherence tomography device were retrieved from the patient files and evaluated. Data from the medical files of 52 patients from the hospital system were evaluated. There was no significant difference between preoperative and postoperative retinal nerve fiber layer (RNFL) thickness, mean central macular thickness, optic disk area, and vertical cup-to-disk ratio (P > 0.05). Epiduroscopy procedures include intermittent or continuous infusion of saline into the epidural area. Currently, the volume of fluid that should be given to the epidural area in epiduroscopy procedures is very controversial. As a result of this study, we concluded that the amount of fluid used during ELNP, at 107.25 mL and 8.33 mL/min, had no effect on the intraocular pressure, optic disk diameter, macular thickness, or peripapillary RNFL thickness; thus, it was safe for ELNP.

Automatic detection and grading of diabetic maculopathy using fundus images

Diabetic maculopathy is one of the leading complications of diabetes that is measured as the significant reason for vision misfortune among individuals around the globe. In this paper, a two stage approach is proposed for automatic detection and grading of diabetic maculopathy based on mathematical morphology. Mainly two features are needed for the detection of maculopathy. One is the macula and other one is hard exudates, based on macula location and Optic Disc (OD) diameter, macular section has been drawn. We validate the presence or absence of hard exudates in the macula section and severity of the maculopathy was assessed. The experiment results performed on images from public database i.e., MESSIDOR indicate that the proposed method achieved encouraging results.

An innovative and simple method, clinically comparable to high-definition optical coherence tomography in quantifying posterior segment lesions in the retina.

Purpose:To introduce a simple and inexpensive method using a fundus contact lens and a reticle, to measure retinal lesions comparing it with values obtained with high-definition optical coherence tomography (HD-OCT). This study considers optic disc as the object for comparison.Methods:Patients underwent routine ophthalmologic examination and their horizontal optic disc diameter was measured, both with the reticle and OCT. For measurement with reticle a simple equation was deduced, x = 0.7y, where x corresponds to the actual image size and y to the reticle scale reading in millimeters.Results:An aggregate of 127 eyes of 75 patients were dilated and examined. The calculated mean diameter according to OCT was 1.639 mm (standard deviation = 0.179) and that assenting to reticle was 1.713 mm (standard deviation = 0.175), with a difference in mean being 0.089 mm.Conclusion:Values obtained by this new method was found to be comparable with the OCT values for retinal measurements, useful for ophthalmologists who cannot afford expensive and sophisticated machines.

Robust segmentation of optic disc and optic cup using statistical Kurtosis test

AbstractGlaucoma is a chronic and irreversible eye disease that leads to the loss of vision. Evaluation of the Cup to Disc Ratio (CDR) plays a prominent role in the early detection of glaucoma. This paper presents a novel algorithm to compute the CDR for the fundus images. In order to calculate the CDR, the vertical diameter of Optic Disc (OD) and the vertical diameter of the Optic Cup (OC) are calculated from the segmented OD and segmented OC, respectively. This study presents OD and OC segmentation algorithms based on a new statistics‐based kurtosis test. A unique OC boundary segmentation method is presented, which is the combination of partial cup extraction and the cup boundary under the Central Retinal Blood vessels (CRBV). A novel preprocessing technique is introduced to extract the CRBV from the automated Region of Interest (ROI). The experimental results confirm that the proposed algorithm outperforms the state‐of‐art OD and OC segmentation on the three publicly available datasets: ORIGA, DIARETDB0, and DIARETDB1. The proposed OD and OC segmentation achieve accuracies of up to 0.99 and 0.97, respectively. In addition, the proposed model achieves excellent CDR evaluation with an average error percentage reduced to up to 9.6496 for the considered datasets.

Retinal vessel oximetry as a sensitive metabolic monitoring method for transcorneal electrical stimulation in retinitis pigmentosa

AbstractBackgroundTranscorneal electrical stimulation (TES; OkuStim®) is a novel therapy method for patients with retinitis pigmentosa (RP). With progression of RP, loss of photoreceptors leads to less oxygen consumption and lower demand in the inner retina. Retinal oximetry (RO) as a non‐invasive method to analyze oxygen saturation in retinal vessels promises to be a useful therapy monitoring tool. The aim of our study was to compare the RO parameters at baseline and following TES.MethodsA total of 43 eyes of 22 subjects (11♀ 11♂) suffering from RP were examined. Stimulation was performed for 30 minutes weekly at 200% of the individual phosphene threshold on both eyes. The oxygen saturation was examined at baseline (BL), 1 week and 6 months after TES stimulation with the oxygen saturation tool of the Retinal Vessel Analyser (IMEDOS Systems UG, Germany). The global oxygen saturations, within 1.0–1.5 optic disc diameters from the disc margin, in retinal arterioles (A‐SO2; %) and venules (V‐SO2; %) were estimated and their difference (A‐V SO2; %) was calculated. In addition, we evaluated the diameters in the corresponding arterioles (D‐A; μm) and venules (D‐V; μm). ANOVA‐based linear mixed‐effects models were calculated with SPSS®.ResultsSix months after TES the A‐SO2 showed a tendency to increase (from 96.48 ± 12.27% to 100.15 ± 5.56%, p = 0.09), while the V‐SO2 showed a slight decrease (from 61.61 ± 12.78% to 59.79 ± 11.15%, p = 0.48). The A‐V SO2, which represents the oxygen consumption of the retina, showed a significant increase from 34.87 ± 9.38% at BL to 41.36 ± 9.18% after 6 months (p = 0.02). TES had no influence on the D‐A and D‐V (p &gt; 0.6).ConclusionThese data indicate that TES therapy in RP leads to an increased oxygen consumption of the retina. Thus, RO proves to serve as a sensitive monitoring method for TES therapy in RP patients.

Retinal vessel oximetry in children with inherited retinal diseases

AbstractBackgroundAlterations in retinal oxygen metabolism have already been confirmed in eldery subjects with retinitis pigmentosa (RP). Hovewer, whether this is a also a feature in children affected by RP has not been studied yet. The aim of our study was to compare retinal oxymetry (RO) parameters whithin children with inherited retinal diseases (IRDs), as well as agains those of carriers and healthy controls.MethodsA total of 68 children (136 eyes) of were examined: 16 with IRDs (32 eyes) were compared to those of 11 IRD carriers (22 eyes) and of 41 healthy children (82 eyes). RO was performed with the oxygen saturation tool of the Retinal Vessel Analyser (RVA; IMEDOS, Germany). The mean oxygen saturations, within 1.0–1.5 optic disc diameters from the disc margin, in the retinal arterioles (A‐SO2;%) and venules (V‐SO2;%) were estimated and their difference (A‐V SO2;%), was calculated. The corresponding arterioles (D‐A;μm) and venules (D‐V;μm) were evaluated, as well. For statistical evaluation ANOVA‐based linear mixed‐effects models were calculated with SPSS®.ResultsThe V‐SO2 showed a statistically significant increase in RP eyes (67.00 ± 7.48%) when compared to healthy controls (59.07 ± 11.98%, p=0.03), but also to children with other IRDs and to carriers (p ≤ 0.03). The A‐V SO2 showed a statistically significant decrease in RP eyes (32.62 ± 4.03%), when compared to eyes suffering from macular dystrophies (MD, 44.35 ± 10.55%, p = 0.05) or cone‐rod‐dystrophies (CRD, 43.29 ± 10.55, p = 0.03). The D‐V, even if not reaching statistically significant level, showed a trend for RP to be slightly attenuated (102.31 ± 8.20 μm) when compared to controls (108.76 ± 20.87 μm; p = 0.07).ConclusionThese data indicate that children suffering RP show early metabolic alterations. With aging and progression of RP the sign of vascular attenuation seems to be a secondary effect of neurovascular remodeling. Here, RO seems to be a useful screening tool for metabolic dysfunction within a family affected from RP.

Metabolic monitoring of transcorneal electrical stimulation in retinitis pigmentosa.

Transcorneal electrical stimulation (TES) is a novel treatment approach for patients with retinitis pigmentosa (RP). With progression of RP, loss of photoreceptors leads to less oxygen consumption and lower demand in the retina. Retinal oximetry (RO), as a non-invasive method to analyse oxygen saturation in retinal vessels, promises to be a useful therapy monitoring tool. The aim of our study was to observe changes in RO that would be attributed to therapeutic intervention. A total of 43 eyes of 22 subjects (11♀ 11♂) suffering from RP were examined at baseline, after the first stimulation, 1 week and 6 months after TES (OkuStim®). Stimulation was performed for 30 min weekly at 200% of the individual phosphene threshold, simultaneously on both eyes. The oxygen saturation was examined at baseline and following TES stimulation with the oxygen saturation tool of the Retinal Vessel Analyser (RVA; IMEDOS Systems UG, Jena, Germany). The global oxygen saturation parameters (in %), within 1.0-1.5 optic disc diameters from the disc margin, in retinal arterioles (A-SO2) and venules (V-SO2) were estimated and their difference (A-V SO2) was calculated. In addition, we evaluated the diameters (in μm) in the corresponding arterioles (D-A) and venules (D-V). ANOVA-based linear mixed-effects models were calculated with SPSS®. Six months after TES treatment, the mean A-SO2 increased (from 96.48 ± 12.27 to 100.15 ± 5.56%, p = 0.09), while the V-SO2 decreased (from 61.61 ± 12.78 to 59.79 ± 11.15%, p = 0.48). The A-V SO2, which represents the oxygen consumption of the retina, showed a statistically significant increase from 34.87 ± 9.38% at baseline to 41.36 ± 9.18% after 6 months (p = 0.02). TES had no influence on the D-A and D-V (p > 0.6). These data indicate that TES therapy in RP leads to an increased oxygen consumption of the retina. RO may thus serve as a sensitive monitoring method for TES therapy in RP.