High-definition Optical Coherence Tomography Research Articles

Diagnostic Accuracy of Corneal and Epithelial Thickness Map Parameters to Detect Keratoconus and Suspect Keratoconus.

To establish the diagnostic accuracy of corneal and epithelial thickness measurements obtained by spectral-domain optical coherence tomography (SD-OCT) in detecting keratoconus (KC) and suspect keratoconus (SKC). This retrospective study reviewed the data of 144 eyes separated into three groups by the Sirius automated corneal classification software: normal (N) (n = 65), SKC (n = 43), and KC (n = 36). Corneal thickness (CT) and epithelial thickness (ET) in the central (0-2 mm) and paracentral (2-5 mm) zones were obtained with the Cirrus high-definition OCT. Areas under the curve (AUC) of receiver operator characteristic (ROC) curves were compared across groups to estimate their discrimination capacity. ROC curve analysis revealed excellent predictive ability for ET variables: minimum (Min) ET (0_2), minimum-maximum (Min-Max) ET (0_2), superonasal-inferotemporal (SN-IT) ET (2_5), Min-Max ET (2_5), and Min ET (2_5) to detect keratoconus (AUC > 0.9, all). Min-Max CT (0_2) was the only CT parameter with excellent ability to discriminate between KC and N eyes (AUC = 0.94; cutoff = ≤-32 μm). However, both ET and CT variables were not strong enough (AUC < 0.8, all) to differentiate between SKC and N eyes, with the highest diagnostic power for Min-Max ET (2_5) (AUC = 0.71; cutoff = ≤-9 μm) and central corneal thickness (CCT) (AUC = 0.76; cutoff = ≤533 μm). These results demonstrate that OCT-derived CT and ET are able to differentiate between KC and N eyes, with a high level of certainty. However, Min-Max ET (2_5) was the parameter with the highest ability to detect suspect keratoconus.

Study protocol of the BASINEL Study: a pragmatic randomised controlled trial investigating treatment versus no treatment of low-risk basal cell carcinomas in older persons

IntroductionBasal cell carcinomas (BCCs) represent 70% of all skin cancers. These tumours do not metastasise but are locally invasive if left untreated. There is a high incidence of BCC in...

Ganglion cell inner plexiform layer thickness measured by optical coherence tomography to predict visual outcome in chiasmal compression

We evaluated the prognostic value of the preoperative macular ganglion cell inner plexiform layer (mGCIPL) thickness along with peripapillary retinal nerve fiber layer (pRNFL) thickness measured by optical coherence tomography (OCT) and estimated an optimal cut-off value to predict postoperative visual field (VF) recovery in adult patients with chiasmal compression after decompression surgery. Two hundred forty eyes of 240 patients aged 20 years or older for which preoperative high-definition Cirrus OCT parameters and pre- and postoperative visual function data were available. The prognostic power of pRNFL and mGCIPL thicknesses for complete postoperative VF recovery or significant VF improvement (improvement ≥ 2 dB in the mean deviation) were assessed. The cut-off values for OCT parameters for VF recovery were estimated. The study found that the higher the preoperative pRNFL and mGCIPL thicknesses, the higher the probability of complete postoperative VF recovery (p = 0.0378 and p = 0.0051, respectively) or significant VF improvement (p = 0.0436 and p = 0.0177, respectively). The area under the receiver operating characteristic analysis of preoperative OCT parameters demonstrated that the mGCIPL thickness showed an area under the curve (AUC) of more than 0.7 for complete VF recovery after decompression surgery (AUC = 0.725, 95% CI: 0.655, 0.795), and the optimal mGCIPL thickness cut-off value for complete VF recovery was 77.25 µm (sensitivity 69% and specificity 69%). Preoperative mGCIPL thickness was a powerful predictor of visual functional outcome after decompression surgery for chiasmal compression.

Comparison of outcomes of idiopathic macular holes treated by vitrectomy with air or silicone oil tamponade based on the hole size.

To compare the efficacy of vitrectomy combined with air or silicone oil in the treatment of idiopathic macular hole (IMH). According to the results of high-definition optical coherence tomography (HD-OCT), 75 cases (75 eyes) of IMH in stage II-IV (Gass stage) in the General Hospital of Chinese PLA from January 2017 to December 2019 were collected for this retrospective study. The best corrected visual acuity (BCVA) and minimum diameter of IMH (MMHD) were measured. Eyes underwent vitrectomy combined with internal limiting membrane peeling operation, and were divided into disinfection air group (30 eyes) and silicone oil group (45 eyes) according to the intraocular tamponade. For MMHD≤400 µm (MMHD1), there were 23 eyes in air group and 16 eyes in silicone oil group. For MMHD2>400 µm (MMHD2), there were 7 eyes in air group and 29 eyes in silicone oil group. One month after surgery, the closure rates of IMH and BCVA were compared and analyzed. According to HD-OCT, the closure shape was graded with A (bridge closure) and B (good closure). The closure rates of air group and silicone oil group were 86.67% and 95.56% respectively with no significant difference (P>0.05); For MMHD1, those of air group and silicone oil group were 95.65% and 100% respectively with no significant difference (P>0.05); For MMHD2, those of air group and silicone oil group were 57.14% and 93.10% respectively, and those of the silicone oil group were higher than the air group (P<0.05). There was no significant difference in the closure shape grade between MMHD1 air group and silicone oil group (P>0.05). The proportion of Grade B in MMHD2 silicone oil group was higher than that in the air group (P<0.05). BCVA of each group after operation was better than that before operation, and there was no significant difference between air group and silicone oil group. While among them, MMHD1 air group was better than silicone oil group (P<0.05), and there was no significant difference between MMHD2 air group and silicone oil group (P>0.05). For smaller IMH (≤400 µm), the efficacy of vitrectomy combined with air should be considered better than silicone oil; for larger IMH (>400 µm), the efficacy of silicone oil may be better than air.

Visualizing Inside Conduits—Intraoperative Screening of Grafts by Optical Coherence Tomography

PurposeSaphenous vein graft (SVG) failure is a complex phenomenon, with technical, biologic, and local factors contributing to early and medium- and long-term failure after coronary artery bypass graft. Both technical and conduit factors may have significant impact on early SVG failure. DescriptionWe review the complex factors that play a pathogenic role in SVG failure, followed by review of the existing literature on potential utility of high-definition optical coherence tomography (OCT) in comprehensive intraoperative assessment of SVGs. EvaluationWe describe a new technique for intraoperative acquisition of OCT images in the harvested SVGs and introduce a classification system for pathologic processes that can be detected in the harvested SVG conduits by OCT. ConclusionsThe potential impact on early graft failure of the exclusion of segments of SVGs that are less than optimal (ie, containing fibroatheroma, retained thrombus, sclerotic valves, or procurement injury) will be examined in the randomized controlled OCTOCAB (Intraoperative Optical Coherence Tomography of the Saphenous Vein Conduit in Patients Undergoing Coronary Artery Bypass Surgery) trial.

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) and high-density (HDL-C) fractions, and triglycerides (TG) were measured, under a controlled meal regimen, during daytime hours in 114 patients diagnosed with primary open-angle glaucoma (POAG). RGC damage was assessed by high-definition optical coherence tomography (HD-OCT). Analysis of eight clock, clock-related, and melatonin receptor gene polymorphisms was performed on 19 patients. RGC loss was associated with changes in lipid metabolism in a time-dependent manner. Morning (08:00) values of HDL-C (r = 0.613, p &lt; 0.0001) and TG (r = 0.568, p &lt; 0.0001) correlated positively with RGC global loss, while LDL-C at 08:00 had a weak correlation (r = 0.235; p = 0.012) but showed a strong correlation in the evening (20:00) (r = 0.533, p &lt; 0.0001). The morning–evening gradients (MEGs, changes at 20:00 versus 08:00) in TC and LDL-C changed sign from a negative to a positive association in patients exceeding the 15% two-eye mean GLV threshold. MEG (LDL-C higher in the evening than in the morning) was positive only in POAG patients with the CLOCK_3111 TT genotype.

The macular inner plexiform layer thickness as an early diagnostic indicator for Parkinson’s disease

Whether structural alterations of intraretinal layers are indicators for the early diagnosis of Parkinson’s disease (PD) remains unclear. We assessed the retinal layer thickness in different stages of PD and explored whether it can be an early diagnostic indicator for PD. In total, 397 [131, 146, and 120 with Hoehn-Yahr I (H-Y I), H-Y II, and H-Y III stages, respectively] patients with PD and 427 healthy controls (HCs) were enrolled. The peripapillary retinal nerve fiber layer (pRNFL), total macular retinal thickness (MRT), and macular volume (TMV) were measured by high-definition optical coherence tomography, and the macular intraretinal thickness was analyzed by the Iowa Reference Algorithms. As a result, the PD group had a significantly lower average, temporal quadrant pRNFL, MRT, and TMV than the HCs group (all p < 0.001). Moreover, the ganglion cell layer (GCL), inner plexiform layer (IPL), and outer nuclear layer were thinner in patients with PD with H-Y I, and significantly decreased as the H-Y stage increased. In addition, we observed that GCL and IPL thicknesses were both correlated with Movement Disorder Society-Unified Parkinson’s Disease Rating Scale III (MDS-UPDRS III) scores and non-motor symptoms assessment scores. Furthermore, macular IPL thickness in the superior inner (SI) quadrant (IPL-SI) had the best diagnostic performance in patients with PD with H-Y I versus HCs, with a sensitivity and specificity of 75.06% and 81.67%, respectively. In conclusion, we confirmed the retinal structure was significantly altered in patients with PD in different clinical stages, and that GCL and IPL changes occurred during early PD disease and were correlated with MDS-UPDRS III scores and non-motor symptoms assessment scores. Furthermore, macular IPL-SI thickness might be performed as an early diagnostic indicator for PD.

Ganglion Cell-inner Plexiform Layer Thickness Measured by Cirrus High-definition Optical Coherence Tomography Enhances Glaucoma Diagnosis in Patients with Moderate or High Myopia

Objective: To assess the diagnostic ability of Cirrus high-definition optical coherence tomography (HD-OCT) parameters in patients with moderate or high myopia for detecting glaucoma, and to compare the thickness of the macular ganglion cell-inner plexiform layer (GC-IPL) in glaucomatous and normal eyes in both types of myopia.Materials and Methods: This prospective study enrolled moderately (spherical equivalent -3.00 to -6.00 diopters) and highly (spherical equivalent ≤ -6.00 diopters) myopic patients without (controls) and with (study) glaucoma. Cirrus HD-OCT was used to determine the thickness of the peripapillary retinal nerve fiber layer (RNFL) and the GC-IPL. The area under the receiver operating characteristic curve was analyzed to evaluate the glaucoma detection capability of each Cirrus HD-OCT parameter.Results: Seventy eyes (31 moderate myopia, 39 high myopia) were included. The parameters with the best diagnostic ability were minimum GC-IPL, inferior RNFL and average RNFL thickness in moderately myopic eyes, and average RNFL, inferior RNFL and inferotemporal GC-IPL thickness in highly myopic eyes. All parameters were thinner in glaucomatous than in normal eyes in both groups.Conclusion: Although macular GC-IPL thickness demonstrated high ability to detect glaucoma in patients with moderate or high myopia, it should be used in combination with other structural imaging and functional assessments for diagnosing glaucoma.

Predicting Visual Improvement After Macular Hole Surgery: A Combined Model Using Deep Learning and Clinical Features.

PurposeThe purpose of this study was to assess the feasibility of deep learning (DL) methods to enhance the prediction of visual acuity (VA) improvement after macular hole (MH) surgery from a combined model using DL on high-definition optical coherence tomography (HD-OCT) B-scans and clinical features.MethodsWe trained a DL convolutional neural network (CNN) using pre-operative HD-OCT B-scans of the macula and combined with a logistic regression model of pre-operative clinical features to predict VA increase ≥15 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 6 months post-vitrectomy in closed MHs. A total of 121 MHs with 242 HD-OCT B-scans and 484 clinical data points were used to train, validate, and test the model. Prediction of VA increase was evaluated using the area under the receiver operating characteristic curve (AUROC) and F1 scores. We also extracted the weight of each input feature in the hybrid model.ResultsAll performances are reported on the held-out test set, matching results obtained with cross-validation. Using a regression on clinical features, the AUROC was 80.6, with an F1 score of 79.7. For the CNN, relying solely on the HD-OCT B-scans, the AUROC was 72.8 ± 14.6, with an F1 score of 61.5 ± 23.7. For our hybrid regression model using clinical features and CNN prediction, the AUROC was 81.9 ± 5.2, with an F1 score of 80.4 ± 7.7. In the hybrid model, the baseline VA was the most important feature (weight = 59.1 ± 6.9%), while the weight of HD-OCT prediction was 9.6 ± 4.2%.ConclusionsBoth the clinical data and HD-OCT models can predict postoperative VA improvement in patients undergoing vitrectomy for a MH with good discriminative performances. Combining them into a hybrid model did not significantly improve performance.Translational RelevanceOCT-based DL models can predict postoperative VA improvement following vitrectomy for MH but fusing those models with clinical data might not provide improved predictive performance.

Thickness Measurement of Endothelium-Descemet Membrane in Descemt Membrane Detachment Patients Using High-Definition Optical Coherence Tomography.

Purpose: (1) To measure the corneal endothelium-Descemet membrane (EDM) layer thickness in Descemet membrane detachment (DMD) patients in vivo using high-definition optical coherence tomography (HD-OCT), and to investigate its correlation with age. (2) To explore whether the detachment time will affect the EDM thickness. (3) To explore whether the EDM thickness of cornea with DMD was different from that without DMD. Participants: Patients with DMD were divided into three groups. Group 1 included twenty-three patients whose Descemet membrane (DM) was partial or complete detached from the corneal stroma after various ocular surgeries. Group 2 included eight patients from group 1 who underwent twice HD-OCT examination on different days before the DM reattached to the stroma. Group 3 included nine patients from group 1 who had clear grayscale boundary between the DM and stroma in HD-OCT images after DM reattachment. Methods: All patients underwent HD-OCT and EDM thickness was measured using Image -Pro Plus 6.0. In Group 1, regression analyses were used to evaluate the correlation between EDM thickness and age, and the thickness difference between the ≤50-year-old group and the >50-year-old group was analyzed by independent sample t-test. In Group 2, paired samples t-test was used to check whether detachment time would affect EDM thickness. In Group 3, paired samples t-test was used to check whether the EDM thickness of cornea with DMD was different from that without DMD. p < 0.05 was considered significant. Results: In Group 1, the EDM thickness measured on the first post-operative day was 27.8 ± 3.6 μm, and a positive correlation was found between EDM thickness and age (r = 0.619, p < 0.05). The EDM thickness of ≤50-year-old group and >50-year-old group were 23.9 ± 3.2 and 29.2 ± 2.6 μm, and there was a significant difference between the two groups (p = 0.001). In Group 2, the first measurement of EDM thickness was 27.5 ± 4.0 μm, the second measurement was 27.6 ± 4.2 μm, the interval between the two measurements was 2.1 ± 1.6 days, and there was no significant difference between the two measurements (p = 0.328). In Group 3, the EDM thickness with DM detachment was 28.3 ± 3.5 μm, with DM reattachment was 23.4 ± 2.4 μm, there was a significant difference between the two measurements (p = 0.002). Conclusions: The EDM thickness in the state of DMD is thicker than its actual thickness in normal cornea, and EDM thickness of the >50-year-old group is much thicker than that of the ≤50-year-old group.

Evaluation of University of North Carolina OCT Index for Diagnosis of Early Glaucoma

To evaluate the diagnostic performance of the University of North Carolina (UNC) OCT Index based on Cirrus high-definition OCT to discriminate early glaucomatous eyes from normal eyes in clinical practice. Evaluation of diagnostic test or technology. Ninety-eight patients with early glaucoma and 98 age-matched normal subjects. Macular ganglion cell-inner plexiform layer (GCIPL) thickness, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head parameters were measured in each subject. The measurements were run through the UNC OCT algorithm to compare their diagnostic abilities. Area under the curve (AUC) of the receiver operating characteristic and sensitivity at 95% specificity. The AUC of the UNC OCT Index was 0.974. The best AUCs of the single parameters were those of the minimum GCIPL (0.926) of the macular GCIPL, average RNFL (0.916) of the peripapillary RNFL, and rim area (0.964) of the optic nerve head. The AUC of the UNC OCT Index was significantly greater than those of the minimum GCIPL and average RNFL (all P values < 0.05), and also outperformed the rim area. The sensitivity value of the UNC OCT Index (90.8) was greater than that of single OCT parameters (minimum GCIPL, 42.9; average RNFL, 64.3; rim area, 84.7) at 95% specificity. The diagnostic performance of the UNC OCT Index in discriminating early glaucomatous eyes from normal eyes is high and exceeds the best optic nerve head, peripapillary RNFL, and macular GCIPL parameters in clinical practice.

Melatonin, circadian rhythms and glaucoma: current perspective.

Melatonin, circadian rhythms and glaucoma: current perspective.

Comparison of inner macular thickness and superficial macular capillary vessel density acquired using classic and high-definition optical coherence tomography angiography scans

Background: In ophthalmology, thickness and vessel density (VD) measurements for the 6 x 6 mm inner macular retinal area have received increasing attention in glaucomatous progression research. For this area, the Angiovue optical coherence tomography system introduced a 304 x 304 A/B scans function (classic Angio Retina scan) in 2014, and a 400 x 400 A/B scans function (high-definition [HD] Angio Retina scan) in 2017. These scan types cannot be used in combination for the software provided for progression analysis.Purpose: Since losing data for 3 years may negatively influence progression analysis, we investigated whether clinically significant differences exist between consecutive measurements acquired with these scan types on the same eyes.Methods: As a part of our noninterventional prospective glaucoma imaging study, primary-open-angle glaucoma patients (POAG group), and ocular hypertensive and healthy control participants (structurally undamaged group) were imagedusing both the classic and the HD Angio Retina scans, respectively, without changing the patients’ position. High-quality images were obtained on 12 POAG eyes of 12 consecutive POAG patients, and 10 healthy and ocular hypertensive eyes of 10 consecutive participants before the data collection had to be suspended due to the new coronavirus epidemic.Results: For Early Treatment Diabetic Retinopathy Study image area, the mean difference (classic minus HD value) was 0.02 ± 0.37 μm for inner retinal thickness (P = 0.869) and 0.33 ± 1.33 % (P = 0.452) for superficial capillary VD in the structurally normal group (between-methods difference: ≤ 0.8% of the respective normal value). In the POAG group, the corresponding figures were -0.07 ± 1.22 μm for inner retinal thickness (P = 0.854; between-methods difference: 0.6% of the normal value) and 1.12 ± 2.58 % for superficial capillary VD (P = 0.158; classic scan value minus HD scan value: 1.12 ± 2.58 %; 2.3% of the normal value).Conclusion: Our results suggest that combined use of thickness and VD values for structurally normal eyes and thickness values for POAG eyes derived from classic and HD scans, respectively, for progression analysis can be reasonable since the differences between the corresponding values are small. However, combining the corresponding VD parameters for POAG eyes is useful only when the follow-up time before the scan type change is long enough to counterbalance the effect of the change on the result.

Simultaneous changes in visual acuity, cortical population receptive field size, visual field map size, and retinal thickness in healthy human aging

Healthy human aging is associated with a deterioration of visual acuity, retinal thinning, visual field map shrinkage and increasing population receptive field sizes. Here we ask how these changes are related to each other in a cross-sectional sample of fifty healthy adults aged 20–80 years. We hypothesized that age-related loss of macular retinal ganglion cells may lead to decreased visual field map sizes, and both may lead to increased pRF sizes in the cortical central visual field representation. We measured our participants’ perceptual corrected visual acuity using standard ophthalmological letter charts. We then measured their early visual field map (V1, V2 and V3) functional population receptive field (pRF) sizes and structural surface areas using fMRI, and their retinal structure using high-definition optical coherence tomography. With increasing age visual acuity decreased, pRF sizes increased, visual field maps surface areas (but not whole-brain surface areas) decreased, and retinal thickness decreased. Among these measures, only functional pRF sizes predicted perceptual visual acuity, and Bayesian statistics support a null relationship between visual acuity and cortical or retinal structure. However, pRF sizes were in turn predicted by cortical structure only (visual field map surface areas), which were only predicted by retinal structure (thickness). These results suggest that simultaneous disruptions of neural structure and function throughout the early visual system may underlie the deterioration of perceptual visual acuity in healthy aging.

Determinants of macular ganglion cell\u2013inner plexiform layer thickness in normal Chinese adults

BackgroundDemographic, systemic and ocular factors may impact macular ganglion cell–inner plexiform layer (GCIPL) thickness measurements. This study aimed to investigate the influences of multiple potential determinants of macular GCIPL thickness in normal Chinese adults.MethodsThis was a retrospective study conducted on 225 normal eyes from 225 healthy Chinese adults. GCIPL thickness were obtained using Cirrus high-definition optical coherence tomography (OCT). The age, gender, laterality, spherical equivalent (SE) refractive error, intraocular pressure (IOP), axial length (AL), central cornea thickness (CCT), circumpapillary retinal nerve fibre layer (pRNFL) thickness and OCT signal strength were recorded and their respective effect on GCIPL thickness parameters were evaluated.ResultsThe mean (± SD) average, minimum, superotemporal, superior, superonasal, inferonasal, inferior, and inferotemporal GCIPL thickness was 84.56 ± 5.36, 81.32 ± 5.58, 83.08 ± 5.37, 85.70 ± 5.95, 87.15 ± 6.26, 85.07 ± 6.11, 82.46 ± 5.76, and 83.88 ± 5.59 μm, respectively. Determinants of thinner GCIPL thickness were older age (P = 0.001–0.117; effects enhanced if age over 40 years), thinner pRNFL (all P < 0.001), and weaker signal strength (all P < 0.001). No significant difference was found between males and females (P = 0.069–0.842), and between right eyes and the left eyes (P = 0.160–0.875) except that of superonasal GCIPL thickness (P < 0.001). There was no significant correlation between GCIPL thickness and SE, IOP, CCT, and AL (P = 0.135–0.968).ConclusionsIndividual determinants associated with thinner GCIPL thickness were older age (particularly over 40 years of age), thinner pRNFL, and weaker OCT signal strength. This is relevant in comprehensively understanding the normative data and differentiating normal aging from abnormalities.

Optical coherence tomography

During the past decade, noninvasive imaging has emerged as a valuable tool in clinical dermatology and dermatologic research. Optical coherence tomography (OCT) is one such type of noninvasive imaging. OCT uses the principle of interferometry to produce real-time images. A low-power diode laser shines infrared light onto tissues, which reflects back to an optical fiber interferometer. Using time delay and the backscattered light intensity, a two-dimensional image akin to an ultrasound is rendered. We review the history, types, and modalities of OCT, plus the many applications of frequency domain, high definition, and dynamic OCT in practice, including its utility in diagnosis, monitoring, and grading disease severity in a variety of cutaneous conditions.

Evaluation of the Cirrus High-Definition OCT Normative Database Probability Codes in a Black American Population

Race-adjusted interpretation of data from Cirrus high-definition OCT (HD-OCT) devices is not standard practice. The aim of this study is to evaluate differences in peripapillary retinal nerve fiber layer (RNFL) thickness between healthy Black Americans and the Cirrus HD-OCT normative database. This is a cross-sectional observational study using control patients recruited from the greater Philadelphia, Pennsylvania, area. A total of 466 eyes were included in this study. Subjects were retrospectively identified from the control cohort of the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study. Using an age-stratified or linear regression method, we reclassified white-green-yellow-red color probability codes for RNFL thicknesses by quadrant. The distribution of reclassified color codes was compared with the expected 5%-90%-4%-1% percentiles and to the original color codes by the Cirrus machine. Average RNFL thickness in the POAAGG control cohort was thinner than in the Cirrus normative database in all except the nasal quadrant. The original color codes of the POAAGG cohort did not fall into the expected distributions, with more RNFL measurements assigned as white and red codes than expected (9.5% and 1.7%) and fewer measurements assigned as green and yellow codes than expected (85.3% and 3.5%) (P < 0.001). Compared with the original Cirrus machine, reclassification using linear regression produced color codes closest to the expected distributions (P= 0.09). The proportion of abnormal results shifted closer to the expected 5% in the nasal (1.3%, P < 0.001 vs. 3.0%, P= 0.048) and temporal (8.2%, P= 0.002 vs. 3.6%, P= 0.18) quadrants. Results further establish the presence of structural differences in the RNFL of Black American patients. Color code reclassification suggests that the existing Cirrus database may not be accurately evaluating glaucomatous nerves in patients of African descent. This study addresses an unmet need to assess Cirrus HD-OCT color probability codes in a Black American population.

Acute Macular Neuro-retinopathy: a Rare Retinal Disorder, Presenting as Paracentral Scotoma

Acute Macular Neuro-retinopathy (AMN) is a rare clinical entity. We present a case of 26 years old male who presented with one-week old history of sudden onset of decrease vision in left eye associated with paracentral scotomas. Dilated fundus examination of the left eye showed multiple reddish brownish petalloid para-foveal lesions with apex pointing toward the fovea. OCT showed hyper-reflective bands in the Outer Nuclear Layer and Outer Plexiform Layer along with disruption of ellipsoid zones. Amsler grid drawn by the patient and the visual field showed scotoma corresponding to the macular lesion. The cause turned out to be undiagnosed essential hypertension. Purpose of presenting this case is that High Definition Optical coherence tomography (SD-OCT) makes diagnosis of some rare conditions easy and fast for an ophthalmologist, that might be misdiagnosed or missed with conventional OCT and FFA imaging test.&#x0D; Key Words: Acute Macular Neuro-retinopathy, Spectral Domain Optical Coherence Tomography, Paracentral Scotoma.

A study of retinal nerve fiber layer thickness and other optic nerve head parameters in cases of amblyopia

Introduction: Amblyopia is a disorder of decreased visual acuity and contrast sensitivity, studies in past have shown retinal changes in amblyopic eyes, which was refuted by other studies. Studies in the recent past have reported variable results on retinal nerve fiber layer (RNFL) thickness in amblyopic eyes. Therefore, there is still a gap in present knowledge. This study was conducted to study RNFL thickness and other optic nerve head (ONH) parameters in amblyopic and better fellow eyes. Materials and Methods: A total of 30 diagnosed cases of amblyopia (four cases of meridional, 11 cases of anisometropic, three cases of strabismic, eight cases of ammetropic, and four cases of form deprivation amblyopia) were divided into two groups: Group A (amblyopic eyes – 30 eyes) and Group B (better fellow eyes – 30 eyes). All the eyes underwent visual acuity assessment, refraction (under cycloplegia), anterior segment evaluation, and fundus evaluation. All the patients underwent ONH evaluation by Cirrus 500 spectral-domain high-definition optical coherence tomography, before and after occlusion therapy. The ONH parameters studied were average RNFL thickness, rim area, disc area, and cup volume. The data were analyzed using SPSS version 25:00. Results: The RNFL thickness was less in amblyopic eyes as compared to normal fellow eyes, (P = 0.002). There was a positive correlation between RNFL thickness and rim area in both the groups, but it was significant (P = 0.02) in Group A only. No statistically significant difference was found between the rim area, disc area, and cup volume between the two groups. Conclusion: The RNFL thickness was found to be significantly less in amblyopic eyes, also there was a significant positive correlation between RNFL thickness and rim area in Group A (P = 0.02).

Evaluation of Retinal Nerve Fiber Layer, Ganglion Cell-Inner Plexiform Layer, and Optic Nerve Head in Glaucoma Suspects With Varying Myopia.

Myopic glaucoma suspects, particularly with high myopia, experience thinning of nontemporal parameters of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL), without change in optic nerve head (ONH) parameters. The aim was to assess the effect of myopia on RNFL, GCIPL, and ONH parameters in glaucoma suspects. Seventy-six eyes of glaucoma suspects studied with Cirrus high definition optical coherence tomography were divided into low (n=27), moderate (n=25), and high myopia (n=24) groups. Optical coherence tomography parameters were correlated with spherical equivalent (SE) and evaluated with areas under the receiver operating characteristic curve for quantifying diagnostic ability to differentiate high myopia from nonhigh myopia. In high myopia, SE was positively correlated with thinning of average, minimum, and nontemporal GCIPL and thinning of average and nontemporal RNFL (P<0.05 for all), but not for inferior RNFL (P=0.28). In moderate myopia, SE was correlated with thinning of inferonasal and minimum GCIPL as well as superior and inferior RNFL (P<0.05 for all). SE was not correlated with ONH parameters in moderate or high myopia (P>0.05). The largest areas under the receiver operating characteristic curve for RNFL and GCIPL parameters were for superior (0.82) and superonasal (0.80) regions, respectively, with comparable diagnostic ability (P=0.74). High myopia, in particular, is associated with thinning of average RNFL, average and minimum GCIPL, and nontemporal parameters of both RNFL and GCIPL, warranting consideration of refractive status in glaucoma suspects.