Retinal Nerve Fiber Layer Damage Research Articles

Optic nerve head and retinal nerve fiber layer changes by spectral domain optical coherence tomography in glaucoma suspects at tertiary care hospital

Introduction: Glaucoma is a progressive optic neuropathy characterized by functional loss or optic nerve dysfunction which is one of the leading causes of irreversible but preventable blindness. The aim of the study was to determine which of the retinal nerve fiber layer and optic nerve head parameters are reliable markers of optic nerve damage in glaucoma suspects. Methods: Observational cross-sectional study of 250 patient’s including147 glaucoma suspect eyes, 103 normal eyes. All subjects underwent complete eye examination and imaging with the spectral domain optical coherence tomography (SD-OCT) cirrus-TM OCT (Carl Zeiss Meditec, Dublin, CA). Retinal nerve fiber layer (RNFL) and optic nerve head (ONH) OCT protocols were used to evaluate all study participants. The main outcome measures were the difference in OCT parameters among groups. Results: Study shows statistically significant difference in the average RNFL thickness, superior, nasal, inferior, temporal quadrants, rim area, cup volume, average cup to disc ratio (CDR), vertical CDR with P value <0.001 between the two groups. Average CDR, vertical CDR and cup volume had significantly greater AROC values (ROC: 0.99, 0.98, 0.95) than RNFL parameters for discriminating glaucoma suspects from normal eyes. Conclusion: Assessment of RNFL, macular and ONH damage with SD-OCT has been proven useful for diagnosing the disease at different levels of severity, as well as for quantifying risk in glaucoma suspects. In our study ONH measurements, as provided by the SD OCT, have more diagnostic value than RNFL parameters in the diagnosis of glaucoma suspects from normal. Keywords: glaucoma suspects; optic nerve head; retinal nerve fiber layer; optical coherence tomography

Peripapillary microvasculature and retinal nerve fiber layer damage according to the severity of diabetic retinopathy.

To identify damage to the inner retinal layer and microvasculature in the peripapillary area according to the severity of diabetic retinopathy (DR). Patients were divided into four groups: control (group 1), type 2 diabetes (T2DM) without DR (group 2), mild to moderate nonproliferative DR (NPDR) (group 3), and severe NPDR (group 4). The peripapillary retinal nerve fiber layer (pRNFL) thickness and peripapillary vessel density (VD) were compared. Linear regression analysis was performed to identify factors associated with the DR severity. The average pRNFL thicknesses were 96.2 ± 7.1, 94.1 ± 9.6, 92.0 ± 9.9, and 90.3 ± 12.4μm in groups 1, 2, 3, and 4, respectively (P = 0.003) (post hoc analyses: group 1 vs. group 2, P = 0.529; group 2 vs. group 3, P = 0.627; group 2 vs. group 4, P = 0.172; group 3 vs. group 4, P = 0.823). The VDs of the outer ring were 18.9 ± 0.6, 18.4 ± 0.8, 17.9 ± 1.1, and 17.3 ± 1.6mm-1 in groups 1, 2, 3 and 4, respectively (P < 0.001) (all pairwise comparisons, P < 0.050). In multivariate analysis, the VD of the outer ring (B = - 0.35, P < 0.001) was significantly associated with the DR severity. The peripapillary microvasculature reflects retinal damage following DR progression better than the structure of the pRNFL.

Retinal Nerve Fiber Layer Damage Assessment in Glaucomatous Eyes Using Retinal Retardance Measured by Polarization-Sensitive Optical Coherence Tomography.

To assess the diagnostic performance and structure-function association of retinal retardance (RR), a customized metric measured by a prototype polarization-sensitive optical coherence tomography (PS-OCT), across various stages of glaucoma. This cross-sectional pilot study analyzed 170eyes from 49 healthy individuals and 68 patients with glaucoma. The patients underwent PS-OCT imaging and conventional spectral-domain optical coherence tomography (SD-OCT), as well as visual field (VF) tests. Parameters including RR and retinal nerve fiber layer thickness (RNFLT) were extracted from identical circumpapillary regions of the fundus. Glaucomatous eyes were categorized into early, moderate, or severe stages based on VF mean deviation (MD). The diagnostic performance of RR and RNFLT in discriminating glaucoma from controls was assessed using receiver operating characteristic (ROC) curves. Correlations among VF-MD, RR, and RNFLT were evaluated and compared within different groups of disease severity. The diagnostic performance of both RR and RNFLT was comparable for glaucoma detection (RR AUC = 0.98, RNFLT AUC = 0.97; P = 0.553). RR showed better structure-function association with VF-MD than RNFLT (RR VF-MD = 0.68, RNFLT VF-MD = 0.58; z = 1.99; P = 0.047) in glaucoma cases, especially in severe glaucoma, where the correlation between VF-MD and RR (r = 0.73) was significantly stronger than with RNFLT (r = 0.43, z = 1.96, P = 0.050). In eyes with early and moderate glaucoma, the structure-function association was similar when using RNFLT and RR. RR and RNFLT have similar performance in glaucoma diagnosis. However, in patients with glaucoma especially severe glaucoma, RR showed a stronger correlation with VF test results. Further research is needed to validate RR as an indicator for severe glaucoma evaluation and to explore the benefits of using PS-OCT in clinical practice. We demonstrated that PS-OCT has the potential to evaluate the status of RNFL structural damage in eyes with severe glaucoma, which is currently challenging in clinics.

Longitudinal changes in peri-papillary retinal nerve fiber layer thickness in patients with unilateral branch retinal vein occlusion.

Associations between retinal venous occlusion (RVO), elevated intraocular pressure, and glaucoma have been reported. Further investigations into structural alterations in the fellow eyes of individuals with unilateral RVO have revealed that the peripapillary retinal nerve fiber layer is thinner than in healthy eyes, suggesting that there may be systemic risk factors common to both RVO and glaucoma. We aimed to evaluate changes in peripapillary retinal nerve fiber layer thickness (pRNFLT) among individuals with unilateral branch retinal vein occlusion (BRVO). This prospective observational study recruited 30 individuals (60 eyes) with newly diagnosed unilateral BRVO and macular edema, and a control group of 30 healthy individuals (30 eyes) with no abnormalities on fundus examination or concurrent systemic comorbidities. After baseline measurements, the participants were reassessed at 6, 12, and 24 months by measuring global and sectoral pRNFLT using spectral-domain optical coherence tomography. The mean age and sex distributions were comparable between the patient and control groups (both P > 0.05). When compared to fellow eyes, global and sectoral pRNFLT in eyes with BRVO were significantly higher at baseline (all P < 0.05). Over time, pRNFLT decreased dramatically, and by the conclusion of the two-year follow-up, there was a significant reduction from baseline in the affected eyes (all P < 0.05). Likewise, affected eyes experienced a significant improvement in best-corrected distance visual acuity and central macular thickness over the two-year follow-up (both P ≤ 0.001). Comparing the global and all-sector pRNFLT of fellow eyes in the patient group with those of normal eyes in the control group, there were no significant differences at any visit, except in the temporal sector, which revealed a significant reduction in pRNFLT at 24 months in the fellow eyes of patients with unilateral BRVO (P = 0.02). Patients with unilateral BRVO experienced a significant reduction in pRNFLT in the affected eyes and, to a lesser extent, in the fellow eyes, compared with that of the control arm, suggesting that they are prone to retinal nerve fiber layer damage. The reduction in pRNFLT in the normal fellow eyes of patients with BRVO may be attributed to age or concurrent systemic comorbidities. Further studies with long follow-up periods are required to shed light on the etiology of functional and structural changes in both the retinal nerve fiber layer and ganglion cell complex in the normal and affected eyes of patients with unilateral BRVO.

An Artificial Intelligence Enabled System for Retinal Nerve Fiber Layer Thickness Damage Severity Staging

To develop an objective glaucoma damage severity classification system based on OCT-derived retinal nerve fiber layer (RNFL) thickness measurements. Algorithm development for RNFL damage severity classification based on multicenter OCT data. A total of 6561 circumpapillary RNFL profiles from 2269 eyes of 1171 subjects to develop models, and 2505 RNFL profiles from 1099 eyes of 900 subjects to validate models. We developed an unsupervised k-means model to identify clusters of eyes with similar RNFL thickness profiles. We annotated the clusters based on their respective global RNFL thickness. We computed the optimal global RNFL thickness thresholds that discriminated different severity levels based on Bayes' minimum error principle. We validated the proposed pipeline based on an independent validation dataset with 2505 RNFL profiles from 1099 eyes of 900 subjects. Accuracy, area under the receiver operating characteristic curve, and confusion matrix. The k-means clustering discovered 4 clusters with 1382, 1613, 1727, and 1839 samples with mean (standard deviation) global RNFL thickness of 58.3 (8.9) μm, 78.9 (6.7) μm, 87.7 (8.2) μm, and 101.5 (7.9) μm. The Bayes' minimum error classifier identified optimal global RNFL values of > 95 , 86 to 95 , 70 to 85 and < 70 for discriminating normal eyes and eyes at the early, moderate, and advanced stages of RNFL thickness loss, respectively. About 4% of normal eyes and 98% of eyes with advanced RNFL loss had either global, or ≥ 1 quadrant, RNFL thickness outside of normal limits provided by the OCT instrument. Unsupervised machine learning discovered that the optimal RNFL thresholds for separating normal eyes and eyes with early, moderate, and advanced RNFL loss were 95 , 85 μm, and 70 , respectively. This RNFL loss classification system is unbiased as there was no preassumption or human expert intervention in the development process. Additionally, it is objective, easy to use, and consistent, which may augment glaucoma research and day-to-day clinical practice. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Peripapillary choroidal microvasculature dropout is associated with poor prognosis in optic neuritis.

To identify peripapillary choroidal microvasculature dropout (MvD) in eyes with optic neuritis and its association with longitudinal changes in retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIP) thicknesses following diagnosis. A total of 48 eyes with optic neuritis was evaluated to identify the presence of peripapillary choroidal MvD, defined as a focal capillary loss with no visible microvascular network in choroidal layer, using optical coherence tomography (OCT) angiography (OCTA). Patients were divided based on the presence of MvD. OCT and standard automated perimetry (SAP) conducted at 1, 3 and 6 months follow-up were analyzed. MvD was identified in 20 of 48 eyes (41.7%) with optic neuritis. MvD was most commonly found in the temporal quadrant (85.0%), and peripapillary retinal vessel density in the temporal quadrant was significantly lower in eyes with MvD (P = 0.012). At 6 months follow-up, optic neuritis eyes with MvD showed significantly thinner GCIP in superior, superotemporal, inferior and inferotemporal sectors (P<0.05). No significant difference was noted in SAP parameters. The presence of MvD was significantly associated with thinner global GCIP thickness at 6 months follow-up (OR 0.909, 95% CI 0.833-0.992, P = 0.032). Optic neuritis showed peripapillary choroidal microvascular impairment in the form of MvD. MvD was associated with structural deterioration at macular GCIP. Further studies are necessary to identify the causal relationship between microvascular impairment and retinal nerve fiber layer damage in optic neuritis.

Injection of New PMMA* Loaded Microspheres into Anterior Chamber to Establish a Rabbit Glaucoma Model

Objective: To develop a novel PMMA material microsphere and characterize it. Named it PMMA*.The microsphere was loaded with drugs, and the intraocular pressure of rabbits was increased by anterior chamber injection, so as to establish a new animal model of ocular hypertension. Methods: PMMA* microspheres with a diameter of 50-80μm were prepared, and the drug loading, release and biosafety of PMMA* microspheres were analyzed. PMMA* microsphere suspension was prepared at 1% dosage of atropine sulfate. Eighteen healthy male New Zealand white rabbits were selected, with the right eye as the experimental eye and the left eye as the control eye. They were randomly divided into blank microsphere group, atropine sulfate group and atropine sulfate loaded microsphere group with 6 rabbits in each group. The chronic ocular hypertension model of the right eye was established. Intraocular pressure was monitored postoperatively and Micro-CT was used to determine the position of the microsphere at the anterior chamber Angle. The pathological changes of chronic glaucoma were studied. Results: PMMA* microspheres have the characteristics of micropore structure, adjustable size, slow release, in situ residence and good biosafety. There was no significant difference in preoperative intraocular pressure in rabbits (P>0.05), which was comparable. At 15 days after surgery, the intraocular pressure in experimental eyes was significantly higher than that in control eyes, with statistical significance (P<0.05), and the increase of intraocular pressure caused by drug-loaded PMMA* microspheres was more significant. Micro-CT determined the position of the microsphere in the anterior chamber Angle of rabbit. The atropine sulfate loaded microspheres showed more obvious ganglion cell - retinal nerve fiber layer damage. Conclusions:The PMMA* microspheres synthesized in this study have good drug loading performance and slow release performance. Intraventral injection of drug-loaded PMMA* microspheres can block the outflow of aqueous solution to establish a better chronic glaucoma model.

Association between parapapillary choroidal microvasculature and prognosis of optic neuritis

AbstractPurpose: To identify peripapillary choroidal MvD in eyes with optic neuritis and its association with longitudinal changes in retinal nerve fibre layer (RNFL) and ganglion cell‐inner plexiform layer (GCIPL) thicknesses following diagnosis.Methods: A total of 48 eyes with optic neuritis was evaluated to identify the presence of peripapillary choroidal MvD, defined as a focal capillary loss with no visible microvascular network in choroidal layer, using optical coherence tomography (OCT) angiography (OCTA). Patients were divided based on the presence of MvD. OCT and standard automated perimetry (SAP) conducted at 1, 3 and 6 months follow‐up were analysed.Results: MvD was identified in 20 of 48 eyes (41.7%) with optic neuritis. MvD was most commonly found in the temporal quadrant (85.0%), and peripapillary retinal vessel density in the temporal quadrant was significantly lower in eyes with MvD (p = 0.012). At 6 months follow up, optic neuritis eyes with MvD showed significantly thinner RNFL in the temporal quadrant (p = 0.012) and GCIPL in all sectors (p = 0.007). No significant difference was noted in SAP parameters. The presence of MvD was significantly associated with thinner global GCIPL thickness at 6 months follow‐up (OR 0.905, 95% CI 0.832–0.984, p = 0.019).Conclusions: Optic neuritis showed peripapillary choroidal microvascular impairment in the form of MvD. MvD was associated with structural deterioration at macular GCIPL. Further studies are necessary to identify the causal relationship between microvascular impairment and retinal nerve fibre layer damage in optic neuritis.

Visual field defects and retinal nerve fiber layer damage in buried optic disc drusen: a new insight

To assess the association between buried optic disc drusen (BODD) location using spectral-domain optical coherence tomography (SD-OCT) and the location of associated visual field defects (VFD) using the Garway-Heath mapping. This monocentric retrospective cross-sectional study was led at the authors' institution. Adult patients diagnosed with BODD who had complete records with a reliable Humphrey® 24-2 visual field, macular, and papillary OCT were enrolled. Fisher's exact test was used to measure the association between BODD location and VFD distribution according to Garway-Heath's mapping. Totally 20 eyes of 15 patients were included (60% females). The median age (interquartile range) was 63 (43)y and the median best corrected visual acuity (BCVA) was -0.08 (0.08) log MAR. BODD were mostly located in zones A, E, and F. The minimal rim width (MRW) was globally preserved. The retinal nerve fiber layer (RNFL) was predominantly altered in zones D, E, and F. There was a significant correlation between BODD location and that of RNFL alterations in zones D (P=0.03) and E (P=0.025); Moreover, the presence of BODD in the E zone was significantly related to damaged RNFL in the neighbouring sectors D and F (P=0.012; P=0.02 respectively). Sixty-three percent (12/19) of visual fields were abnormal and there was a significant match (Phi=0.7, P=0.009) between drusen location and VFD only in zone D. BODD do not only affect young patients and can be more harmful than usually expected, as we found VFD in 63% of cases. There is a correspondence between BODD location, RNFL damage, and VFD distributions. The presence of BODD induces the overestimation of MRW, thereby disrupting its sensitivity as an early indicator of ganglion fibers damage.

Ancillary PanoMap OCT shows the progression of glaucomatous papillomacular bundle defect with disc haemorrhage on the fovea–disc axis

Background/aimsTo identify the spatial relationship between disc haemorrhage (DH) on the fovea–disc axis and retinal nerve fibre layer (RNFL) defect in the papillomacular bundle (PMB) using ancillary PanoMap optical coherence...

Can the long term using of pregabalin in fibromyalgia affect the choroid and retinal nerve fiber layer?

In this study, the effects of long-term pregabalin use on the choroid and retinal nerve fiber layer were investigated in the fibromyalgia disease. The patient group consisted of 41 fibromyalgia patients using pregabalin. The control group consisted of 41 newly diagnosed fibromyalgia patients who had not received any treatment yet. Choroidal and retinal nerve fiber layer thickness measurements were performed with Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA, USA) 30 minutes after pupil dilation with 1% tropicamide. There was no difference in subfoveal choroidal thickness, nasal choroidal thickness and temporal choroidal thickness between the patient and control groups (p > 0.05). Increasing the duration of drug use within the patient group was found to thin the retinal nerve fiber layer (p < 0.05). We found that pregabalin had no effect on the choroid, while it had a thinning effect for retinal nerve fiber layer. It is recommended not to be preferred pregabalin in fibromyalgia patients with retinal nerve fiber layer damage such as diabetic retinopathy and glaucoma. Patients treated with pregabalin should have regular control in the ophthalmology clinic.

Global Glaucoma Staging System (GGSS): A New Method to Simultaneously Assess the Severity of Both Functional and Structural Damage in Glaucoma.

Background: The classification of damage in glaucoma is usually based either on visual field or optical coherent tomography (OCT) assessment. No currently available method is able to simultaneously categorize functional and structural damage. Material and Methods: In this study, 283 patients with chronic open-angle glaucoma (OAG) at different stages and 67 healthy subjects were tested with both standard automated perimetry and spectral domain OCT for retinal nerve fiber layer (RNFL) assessment. The visual field data were classified using the Glaucoma Staging System 2, whereas OCT results were processed with the OCT Glaucoma Staging System. These data were used to create a new staging system (global glaucoma staging system, GGSS), in which the severity of visual field and RNFL damage is reported on the Y and X axis, respectively. The GGSS was tested in a different sample of 147 patients with manifest OAG, 56 with preperimetric glaucoma and 43 normal subjects. A six-stage clinical classification, based on the analysis of visual fields and optic disc appearance, was used as gold standard. Results: The GGSS was able to correctly classify in the same stage or within the immediately adjacent stages 145 cases on 147 (98.6%). Fifty-four preperimetric cases (96.4%) were classified as borderline or abnormal (Stage 1 or 2). Here, 41 normal eyes out of 43 were correctly classified as Stage 0, with a specificity of 95.3%. Conclusions: Preliminary results from this study are encouraging and suggest that the new GGSS is able to provide information concerning the severity of structural and functional damage in an integrated manner.

Effect of Systemic Hypertension on Peripapillary RNFL Thickness in Patients With Diabetes Without Diabetic Retinopathy.

Type 2 diabetes mellitus (T2DM) and hypertension (HTN) are both relatively common systemic diseases and cause damage to the retina, such as inner retina reduction and microvascular impairment. The purpose of this study was to identify peripapillary retinal nerve fiber layer (pRNFL) damage by diabetic neurodegeneration and the effects of HTN on the pRNFL thickness in patients with T2DM without clinical diabetic retinopathy. Subjects were divided into three groups: healthy control subjects (group 1), patients with T2DM (group 2), and patients with both diabetes and HTN (group 3). The pRNFL thickness was measured using optical coherence tomography and compared among each group. Linear regression analyses were performed to identify factors associated with pRNFL thickness. A total of 325 eyes were included: 143 eyes in the group 1, 126 eyes in group 2, and 56 eyes in group 3. The mean pRNFL thicknesses of each group were 96.1 ± 7.7, 94.4 ± 8.6, and 91.6 ± 9.6 μm, respectively (P = 0.003). In multivariate linear analyses, diabetes duration (β = -0.236; P = 0.018) and HTN (β = -3.766; P = 0.008) were significant factors affecting the pRNFL thickness in groups 2 and 3. Additionally, the HTN duration was significantly correlated with pRNFL thickness in group 3 (R 2 = 0.121; P = 0.008). In conclusion, patients with T2DM with HTN showed thinner pRNFL thickness than those with T2DM only. Additionally, the duration of HTN was significantly correlated with pRNFL thickness in patients with both diabetes and HTN.

Evaluation of optical coherence tomography angiography findings in patients with multiple sclerosis.

Purpose:To evaluate optical coherence tomography angiography findings in patients with multiple sclerosis (MS).Methods:This prospective noninterventional study was conducted on 30 eyes of relapsing-remitting MS patients. Group (1) included 10 eyes with a history of optic neuritis (ON), group (2) included 10 eyes without any history of optic neuritis (MS-ON), and group (3) included 10 eyes of normal age/sex/refraction matched participants. Optical coherence tomography (OCT) and OCT-A (ZEISS Cirrus™ HD-OCT Model 4000 (Carl Zeiss-Meditec, Dublin, CA) of the optic disc were done for all patients.Results:The best-corrected visual acuity was diminished in MS cases, especially in patients with ON with P value <0.001. The retinal nerve fiber layer (RNFL) thickness showed a significant decrease in the average thickness and in all quadrants, notably the temporal quadrant in group 1 (P < 0.001). Ganglion cell layer thickness was diminished in average thickness and in all quadrants in both groups of MS, but only the first group showed statistical significance with P value <0.001). In respect to optic disc perfusion, Average, superficial, and deep vascular density index (AVDI, VDI 1, VDI 2) were statistically significantly lower in groups 1, 2 with (P-value < 0.001).Conclusion:Decreased vascular perfusion of the optic nerve in MS patients, especially in those with ON is strongly correlated with the damage of RNFL and ganglion cell layer detected by OCT.

Effect of intravitreal ranibizumab and aflibercept injections on retinal nerve fiber layer thickness

The purpose is to evaluate the effects of multiple intravitreal ranibizumab (IVR) and aflibercept (IVA) injections on peripapillary retinal nerve fiber layer (RNFL) thickness in patients with exudative age-related macular degeneration (AMD). This retrospective, observational, consecutive case series study enrolled patients newly diagnosed with monocular exudative AMD from January 2014 to October 2019 who were administered IVR or IVA injections. Normal fellow eyes were included as controls. Medical records and spectral domain optical coherence tomography results were reviewed at baseline and at 3, 6, and 12 months after injection. No statistically significant differences in peripapillary RNFL thickness and intraocular pressure were observed between the treated and fellow eyes in the two groups. The global RNFL thicknesses for the treated eyes decreased significantly after 12 months compared with baseline, but no significant difference was observed in any of the six examined sectors (temporal, superior temporal, superior nasal, nasal, inferior nasal, and inferior temporal). At 12 months, the central macular thickness of the treated eyes decreased significantly. Multiple IVR and IVA injections are apparently safe considering peripapillary RNFL damage in patients with exudative AMD. The decreased RNFL thickness of the global sector was presumably due to anatomical improvement of macular lesions.

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.

Artificial Intelligence Mapping of Structure to Function in Glaucoma.

PurposeTo develop an artificial intelligence (AI)–based structure-function (SF) map relating retinal nerve fiber layer (RNFL) damage on spectral domain optical coherence tomography (SDOCT) to functional loss on standard automated perimetry (SAP).MethodsThe study included 26,499 pairs of SAP and SDOCT from 15,173 eyes of 8878 patients with glaucoma or suspected of having the disease extracted from the Duke Glaucoma Registry. The data set was randomly divided at the patient level in training and test sets. A convolutional neural network (CNN) was initially trained and validated to predict the 52 sensitivity threshold points of the 24-2 SAP from the 768 RNFL thickness points of the SDOCT peripapillary scan. Simulated localized RNFL defects of varied locations and depths were created by modifying the normal average peripapillary RNFL profile. The simulated profiles were then fed to the previously trained CNN, and the topographic SF relationships between structural defects and SAP functional losses were investigated.ResultsThe CNN predictions had an average correlation coefficient of 0.60 (P < 0.001) with the measured values from SAP and a mean absolute error of 4.25 dB. Simulated RNFL defects led to well-defined arcuate or paracentral visual field losses in the opposite hemifield, which varied according to the location and depth of the simulations.ConclusionsA CNN was capable of predicting SAP sensitivity thresholds from SDOCT RNFL thickness measurements and generate an SF map from simulated defects.Translational RelevanceAI-based SF map improves the understanding of how SDOCT losses translate into detectable SAP damage.

Prevalence of Glaucoma among High Myopia

Abstract Background Glaucoma is an optic neuropathy that is characterized by the selective loss of retinal ganglion cells and their axons, which manifests as the loss of the retinal nerve fiber layer (RNFL). Numerous studies have shown that the extent of RNFL damage correlates with the severity of functional deficit in the visual field (VF), and that RNFL measurement by optical coherence tomography (OCT) has good sensitivity for the detection of glaucoma. Purpose To assess the prevalence of glaucoma among high myopic patients and the association between them using standard automated perimetry (SAP) and optical coherence tomography (OCT). Patients and Methods A prospective observational randomized cross sectional study included a total of 80 eyes with high myopia, in the period from November 2017 to April 2018. This cross sectional study included 44 subjects with 80 eyes regarding high myopia using the outpatient services of the Qlawoon Hospital, Cairo, who satisfied the inclusion and exclusion criteria between November 2017 and April 2018 aiming to determine the prevalence of glaucoma in high myopic patients. Results In our study, we depended on the following highly significant parameters in detection of prevalence of glaucoma among high myopic patients: Spherical equivalent median is -12, Vertical cup/disc ratio mean is 0.55, MD median of visual field is – 5.38, PSD mean of visual field is 3.53, GHT is 64.7% outside normal limits, 17.6% border line and 17.6% general reduction of sensitivity and RNFL thickness mean is; for average thickness is 86.37, for superior thickness is 90.06 and for inferior thickness is 82.68 a highly significant P-value. Conclusion Prevalence of glaucoma among our study group is 42.5% depending on Spherical equivalent median, Vertical cup/disc ratio mean, MD median of visual field, PSD mean of visual field, GHT and RNFL thickness.

Corneal endothelial density: An indicator for primary glaucoma progression

Purpose: Glaucoma is a progressive optic neuropathy causing death of retinal ganglion cells and their axons resulting in visual morbidity. This study was aimed to evaluate the impact of primary glaucoma on retinal nerve fiber layer (RNFL) thickness and corneal endothelial damage and to establish any correlation between these two. Materials and Methods: A total of 104 patients (179 eyes) diagnosed as primary open-angle glaucoma (POAG), primary angle-closure glaucoma (PACG), and normotensive glaucoma (NTG) were included in this study. Secondary glaucoma, postviral infection, ocular trauma, ocular surgery, and diabetes mellitus were criteria for exclusion. Average retinal nerve fiber layer (AvRNFL) thickness and endothelial cell count (cell density [CD]) were measured. Statistical analysis was done using Spearman's correlation coefficient. Results: The AvRNFL thickness in POAG (n = 120) was 83.83, PACG (n = 46) was 81.45, and Normotensive (NTG) (n = 13) was 71.07 μ. The mean CD values were 2416.68 cells/mm2, 2622.543 cells/mm2, and 2482.69 cells/mm2, respectively. A significant positive correlation between these two values was observed in POAG (P = 0.004) but not seen in PACG or NTG. Conclusion: Corneal endothelium loss may be an indicator of disease progression and RNFL thinning in patients of POAG. Routine specular microscopy evaluation of these patients can be helpful, and low endothelial counts indicate RNFL damage.

Clinical Predictors of the Region of First Structural Progression in Early Normal-tension Glaucoma.

PurposeThis study aimed to compare the clinical characteristics of patients who showed structural progression in the peripapillary retinal nerve fiber layer (RNFL) first against those who showed progression in the macular ganglion cell-inner plexiform layer (GCIPL) first and to investigate clinical parameters that help determine whether a patient exhibits RNFL or GCIPL damage first.MethodsA retrospective review of medical records of patients diagnosed with early-stage normal-tension glaucoma was performed. All eyes underwent intraocular pressure measurement with Goldmann applanation tonometer, standard automated perimetry, and Cirrus optical coherence tomography at 6-month intervals. Structural progression was determined using the Guided Progression Analysis software. Blood pressure was measured at each visit.ResultsForty-one eyes of 41 patients (mean age, 52.6 ± 16.7 years) were included in the study. In 21 eyes, structural progression was first detected in the RNFL at 54.2 ± 14.8 months, while structural progression was first observed at the macular GCIPL at 40.5 ± 11.0 months in 20 eyes. The mean intraocular pressure following treatment was 13.1 ± 1.8 mmHg for the RNFL progression first group and 13.4 ± 1.8 mmHg for the GCIPL progression first group (p = 0.514). The GCIPL progression first group was older (p = 0.008) and had thinner RNFL at baseline (p = 0.001). The logistic regression analyses indicated that both age and follow-up duration until first progression predicted the region of structural progression (odds ratio, 1.051; 95% confidence interval, 1.001–1.105; p = 0.046 for age; odds ratio, 0.912; 95% confidence interval, 0.840–0.991; p = 0.029 for time until progression).ConclusionsAge of glaucoma patients and time until progression are associated with the region of the first structural progression in normal-tension glaucoma. Further studies exploring the association between glaucomatous progression and the location of damage are needed.