Retinal Nerve Fiber Layer Analysis Research Articles

Changes in retinal nerve fiber layer thickness may be the cause of post-COVID-19 headaches

ABSTRACT Objective The prevalence of post-COVID headaches is not low. The eye can be affected by this infection, but it is not clear yet what the relationship is between persistent headaches and the thickness of the retinal nerve fiber layer (RNFL) after COVID-19 infection this study aims to investigate the relationship between these subjects. Methods In this retrospective study, in patients who have had a persistent headache, SD-OCT analysis of RNFL was obtained, and RNLF thickness values before and after COVID-19 infection were analyzed. Results A total of 26 eyes from 13 patients (nine (69.2%) females, four (30.8%) males) with persistent headaches after COVID-19 infection were studied. The average age was 47,35 years for females and 63 years for males. The mean RNFL thickness of both eyes between before and after COVID-19 infection decreased, which was statistically significant. Conclusion In this study, a correlation between headache and changes in RNLF after COVID-19 infection was found. It may have wider ramifications to look into the COVID-19-associated headache phenotype of people with a history of migraines, contributing to a more comprehensive understanding of migraine pathogenesis. This relationship can provide further insight into this infection.

Comparing Intraocular Pressure, Ocular Blood Flow, and Retinal Nerve Fiber Layer Thickness in Early and Chronic Hypertensives With Normotensives

Purpose To compare blood pressure (BP), intraocular pressure (IOP), ophthalmic artery flow (OAF) velocity, retinal nerve fiber layer (RNFL) thickness, and visual fields in newly diagnosed hypertension (HT) patients (before treatment), chronic HT (on antihypertensive medications >5 years) and normotensives. Methods A prospective, cross-sectional study at a tertiary care centre in India. Three groups of 45 patients each: group 1 - early HT, group 2 - chronic HT, and Group 3 - normotensives, underwent evaluation of BP, IOP by Goldmann applanation tonometry (GAT), OAF velocity by transcranial doppler (TCD), RNFL analysis by spectral-domain optical coherence tomography (SD-OCT), and visual fields. Results The BP was highest in early HT > chronic HT > normotensives (p < 0.001). The IOP of early HT, chronic HT, and normotensives were 15.87 ± 2.19 mmHg, 13.47 ± 1.92 mmHg, and 15.67 ± SD 1.75 mmHg (p < 0.001). The OAF velocity [peak systolic velocity (PSV), end-diastolic velocity (EDV) in cm/sec] was lowest in chronic HT (30.80 ± 7.05, 8.58 ± 1.58) < early HT (35.47 ± 5.34, 10.02 ± 1.74) < normotensives (36.29 ± 4.43, 10.44 ± 2.29), (p < 0.001). The average RNFL thickness was significantly lower in chronic HT (p = 0.022). The PSV, EDV, and MFV showed significant correlation with IOP (r = 0.247, p = 0.004; r = 0.206, p = 0.016; r = 0.266, p = 0.002) and average RNFL thickness (r = 0.309, p= <0.001; r = 0.277, p = 0.001; r = 0.341, p < 0.001) Conclusions Patients with chronic HT demonstrated the lowest retrobulbar flows, IOP and lower RNFL measurements. Lower ocular perfusion may be associated with lower IOP and may be a risk factor for end-organ damage (RNFL) independent of IOP.

THE CORRELATION BETWEEN RETINAL NERVE FIBRE LAYER THICKNESS, OPTIC NERVE HEAD PARAMETER, AND RELATED RISK FACTOR IN GLAUCOMA PATIENT

Introduction and Objective: To investigate the correlation between retinal nerve fibre layer (RNFL) thickness and the past RNFL thickness, related risk factor (gender, age, myopia, intraocular pressure (IOP), blood pressure). And RNFL parameter (symmetricity and four quadrants RNFL thickness) and optic nerve head parameter (rim area and vertical cup disc ratio) Methods: 39 right eyes of both sex and various age underwent examination including IOP measurement, subjective refraction for determining refractive error, and optical coherence tomography (OCT) for RNFL and ONH analysis. The follow up were done after one year. Result: The RNFL symmetricity, superior, nasal, inferior, temporal RNFL thickness showed significance correlation with RNFL thickness (R= 0.487, p= 0.002), (R= 0.915, R= 0.749, R= 0.897, R= 0.702 with p= &lt;0.001), but not showed significance correlation with rim area and vertical cup disc ratio (R= 0.175, p= 0.286) and (R= -0.093, p= 0.574). A significance correlation also showed with increasing age, gender, and systolic blood pressure (R= -0.387, p= 0.015), (R= 0.441, p= 0.005) and (R= -0.418, p= 0.008). But not showed significance correlation with history of past RNFL thickness, refractive error, IOP, and diastolic blood pressure (R= 0.258, p= 0.113), (R= 0.005, p= 0.975), (R= -0.234, p=0.152), and (R= 0.060, p=0.717). Conclusion: RNFL thickness measurements showed significance correlation with RNFL parameter. It is not clear if past RNFL thickness, refractive error and IOP related with RNFL thickness even showed significance correlation with age, gender, and systolic blood pressure. Keywords: Glaucoma, RNFL thickness, optical coherence tomography, optic nerve head

Optic Nerve Head and Retinal Nerve Fiber Layer Analysis in Emmetropic Malay Children.

The study aims to investigate the normal reference values for optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters in emmetropic Malay children, utilizing measurements obtained through Cirrus SD-OCT (Carl Zeiss Meditec, Dublin, CA). A cross-sectional study was conducted on 95 Malay children, aged between seven and 17 years, with no ocular abnormalities. It was held at Hospital Universiti Sains Malaysia, Malaysia, from January 2014 to December 2015. All children underwent a full ocular examination, including refraction and calculation of axial length. ONH and retinal nerve fiber layer thickness (RNFLT) parameters were measured using the Cirrus SD-OCT machine. One eye of each subject was selected randomly for study. The associations between the parameters and the effect of age, gender,axial length, and spherical equivalent (SE) on the measurements were statistically validated. Ninety-five children were involved in the study, with 65 females (68.4%) and 30 males (31.6%). The mean age was 10.6 (2.82) years, the mean intraocular pressure (IOP) was 14.8 (2.81) mmHg, the mean SE-refraction was 0.12 (0.28) diopters, and the mean axial length was 23.03 (0.76) mm. The mean disc area, rim area, and cup volume were 2.32 (0.40) mm2, 1.53 (0.33) mm2, and 0.204 (0.16) mm3, respectively. The average cup-to-disc ratio (SD) (CDR) and the vertical CDR were 0.55 (0.13) and 0.50(0.14). Mean (SD) RNFLT was 102.08 (11.08) μm for all patients. There was a strong positive correlation between the average, superior, and inferior RNFLT with the optical disc area. The rim area and the average, superior, inferior, and nasal RNFLT alsoshowed a significant correlation. The inferiorRNFLT was negatively correlated with the average CDR. There was also a major influence of gender on the disc area. There were no major age, axial length, and SE influences on the measurements. This study provided normative information for ONH and RNFLT parameters in emmetropic Malay children. It was observed that emmetropic Malay males exhibited a significantly larger optical disc area. The increase in RNFLT is correlated with a significant increase in disc and rim areas.

Optic Disc Hypoplasia Assessment in PAX6 -Related Aniridia.

This study aims to characterize optic disc hypoplasia in congenital aniridia using ultra-wide-field imaging (UWFI) and nonmydriatic retinal photography (NMRP). We also investigated the relation between optic disc hypoplasia and foveal hypoplasia. This is a retrospective case series of patients diagnosed with PAX6 -related aniridia in a National Referral Center, who underwent UWFI, NMRP, and spectral-domain optical coherence tomography (SD-OCT) . The disc diameter (DD) and the disc-to-fovea distance (DF) were measured. The DD:DF ratio was used to assess the relative size of the optic disc. The analyses were carried with respect to paired age- and sex-matched healthy controls. SD-OCT was used for foveal hypoplasia grading (from 1 to 4) and retinal nerve fiber layer (RNFL) analysis. Mean manual DD:DF ratio was 0.33 (95% CI: 0.31-0.35) in aniridia patients versus 0.37 (95% CI: 0.36-0.39) in control patients (n = 20, P = 0.005) measured on NMRP and 0.32 (95% CI: 0.30-0.35) in aniridia patients versus 0.37 (95% CI: 0.37-0.39) in control patients (n = 26, P < 0.0001) when assessed on UWFI. Mean semiautomated DD:DF ratio measured on UWFI in aniridia patients was 0.31 (95% CI: 0.29-0.33) versus 0.37 (95% CI: 0.36-0.38) in control patients ( P < 0.0001). Also, a negative correlation was found significant between the grade of foveal hypoplasia and the mean semiautomated DD:DF ratio (r = -0.52, 95% CI: -0.76 to -0.15, P = 0.0067). Finally, a significant negative correlation was found between the peripapillary temporal RNFL thickness and the grade of foveal hypoplasia ( P = 0.0034). The DD:DF ratio is significantly reduced in PAX6 -related aniridia patients and correlates with the severity of foveal hypoplasia. This ratio is a valuable tool for optic disc hypoplasia assessment in congenital aniridia, especially when provided semiautomatically by UWFI.

OPTIC DISK PIT STUFFING-TO DO OR NOT TO DO.

Optic disk pit (ODP) is a subset of spectrum of congenital cavitary anomalies. Optic disk pit maculopathy causes progressive visual deterioration and is addressed with pars plana vitrectomy (PPV) with or without ODP stuffing. We report a case of progressive ODP maculopathy who was taken up for 23-G 3-port PPV, with complete vitreous removal and stuffing of the ODP with autologous sclera and sequential analysis of change in the retinal nerve fiber layer (RNFL) thickness. Spectral-domain optical coherence tomography RNFL analysis at 1 and 12 months follow-up postoperatively showed total RNFL thickness decrease from 130 µm to 103 µm respectively. Hemiquadrant analysis showed slight reduction of superior RNFL thickness from 142 µm to 139 µm. However, in the inferior hemiquadrant, the reduction in mean RNFL thickness seems to be significant from 133 µm to 100 µm at 1 and 12 months respectively. Sector-wise analysis of the RNFL thickness showed maximum reduction in the inferotemporal quadrant and other sectors seemed to be relatively preserved corresponding to the area of scleral stuffing. Retrospective or prospective analysis of RNFL health of patients undergoing surgery for ODP-M with stuffing needs to evaluated.

Peripapillary hyperreflective ovoid mass-like structures and the retinal nerve fiber layer thinning.

We describe a report of three cases of bilateral Peripapillary Hyperreflective Ovoid Mass-Like Structures (PHOMS), their respective multimodal imaging, and retinal nerve fiber layer (RNFL) analysis over time. We performed an elaborated multimodal imaging of three pediatric patients with PHOMS. We performed a visual acuity testing, followed by a biomicroscopic and fundus examination, an additional Optical Coherence Tomography (OCT), fundus autofluorescence (FAF), infra-red (IR), fluorescein angiography (FA), Scanning laser Ophtalmoscopy (SLO), and retro-mode imaging. Furthermore, we analyzed RNFL thickness over several consecutive visits. The multimodal approach exhibited similar characteristics of PHOMS in all eyes, namely a torus-like shaped that was particularly demarcated and well visualized using SLO and retro-mode tool. In all the eyes, we found a downward trend of the RNFL over time. In both the right and left eye, RNFL at presentation averaged at 152.33 ± 25.42 and 130 ± 18.33 microns, respectively. Several weeks after, it averaged at 142 ± 30.34 and 125.67 ± 14.84 microns, respectively. Our report shows a thinning trend of the RNFL thickness over time in patients with PHOMS.

Immediate effect of anti-VEGF injections on optic nerve head: Correlation between intraocular pressure and anatomical peripapillary changes.

This study was designed to investigate retinal nerve fiber layer (RNFL) and radial peripapillary capillaries (RPC) changes on optical coherence tomography (OCT) angiography and OCT thickness alterations associated with acutely increased intraocular pressure after intravitreal injections. This observational clinical study was conducted on 35 eyes (35 patients) with treatment-naïve age-related macular degeneration (AMD) and type 1 or type 2 MNV were enrolled. All patients underwent anti-vascular endothelial grow factor (VEGF) intravitreal injections with 0.05-mL aflibercept (2 mg) between January 2022 and October 2022. Peripapillary OCT angiography perfusion density, retinal nerve fiber layer thickness, and intraocular pressure (IOP) were measured before and immediately after intravitreal injections. In particular, the analysis was performed at the following visits: (T0) 5 to 15 min before the injection of aflibercept; (T1) 2 to 5 min after the injection of aflibercept. Paired t-test was used to compare pre-injection and post-injection values. The mean baseline IOP (T0) value was 17.26 ± 2.4 mmHg and the immediate post-injection IOP (T1) mean value was 34.7 ± 11.50 mmHg (P < 0.01). The mean global RNFL thickness before and immediately after the injection was 100.9 ± 18.8 m and 98.6 ± 17.4 m (P = 0.001). Furthermore, the topographical RNFL analysis showed significant thickness reduction of the nasal and inferior sectors after the procedure when compared to T0 (P = 0.046 and P = 0.001). On the contrary, the mean RCP density changes at T1 did not reach statistically significant (P = 0.636). Furthermore, we found a significant negative correlation between the retinal nerve fiber layer global thickness and the IOP changes (Pearson's correlation = -0.126; P = 0.031). In particular, the nasal RNFL region showed a significant negative correlations with IOP values (Pearson's correlation = -0.198, P = 0,046). We reported acute IOP changes that are associated with reduced RNFL thickness in a group of patients undergoing intravitreal injections of anti-VEGF drugs for neovascular age-related macular degeneration. Moreover, topographical sub-analysis revealed that the nasal RNFL region is most prone to IOP fluctuations. This finding may explain the sudden visual acuity change in patients immediately after injection and may sustain injuries to optic nerve head structures producing glaucomatous damage.

Ocular blood flow in normal tension glaucoma and primary open angle glaucoma

Objectives: The purpose of the study was to study the ocular blood flow (OBF) in primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) by color Doppler imaging (CDI) in the ophthalmic artery (OA), central retinal artery (CRA), and posterior ciliary artery (PCA) and to correlate this with structural and functional damage in glaucoma. Materials and Methods: This was a cross-sectional and observational study. This was a cross-sectional study, in which 30 eyes of each group and controls were studied, CDI was done by a single observer for all cases. Peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistive index (RI) were calculated for OA, CRA, and PCA. Visual fields and retinal nerve fiber layer (RNFL) analysis were done. Results: PSVs and EDVs were lower and RIs were higher for CRA and PCA of NTG and POAG compared to those of controls. The severity of glaucoma (visual field defect) increased when RI of OA was increased in NTG. No such relationship was established between RNFL thinning and OBF. Conclusion: Reduction in PSV and EDV leads to increased RI which is one of the contributory factors in the functional damage in NTG.

Associations between Chronic Kidney Disease and Thinning of Neuroretinal Layers in Multiethnic Asian and White Populations

To evaluate the relationships between chronic kidney disease (CKD) with retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness profiles of eyes in Asian and White populations. Cross-sectional analysis. A total of 5066 Asian participants (1367 Malays, 1772 Indians, and 1927 Chinese) from the Singapore Epidemiology of Eye Diseases Study (SEED) were included, consisting of 9594 eyes for peripapillary RNFL analysis and 8661 eyes for GCIPL analysis. Additionally, 45 064 White participants (87 649 eyes) from the United Kingdom Biobank (UKBB) were included for both macular RNFL analysis and GCIPL analysis. Nonglaucoma participants aged ≥ 40 years with complete data for estimated glomerular filtration rate (eGFR) were included from both SEED and UKBB. In SEED, peripapillary RNFL and GCIPL thickness were measured by Cirrus HD-OCT 4000. In UKBB, macular RNFL and GCIPL were measured by Topcon 3D-OCT 1000 Mark II. Chronic kidney disease was defined as eGFR < 60 ml/min/1.73 m2 in both data sets. To evaluate the associations between kidney function status with RNFL and GCIPL thickness profiles, multivariable linear regression with generalized estimating equation models were performed in SEED and UKBB data sets separately. Average peripapillary and macular RNFL thickness and macular GCIPL thickness. In SEED, after adjusting for age, gender, ethnicity, systolic blood pressure, antihypertensive medication, diabetes, hyperlipidemia, body mass index, smoking status, and intraocular pressure, presence of CKD (β=-1.31; 95% confidence interval [CI],-2.37 to-0.26; P= 0.015) and reduced eGFR (per10ml/min/1.73 m2; β=-0.32; 95% CI,-0.50 to-0.13; P= 0.001) were associated with thinner average peripapillary RNFL. Presence of CKD (β=-1.63; 95% CI,-2.42 to-0.84) and reduced eGFR (per10 ml/min/1.73 m2; β=-0.30; 95% CI,-0.44 to-0.16) were consistently associated with thinner GCIPL in SEED (all P < 0.001). In UKBB, after adjusting for the above-mentioned covariates (except ethnicity), reduced eGFR (per 10 ml/min/1.73 m2; β=-0.06; 95% CI,-0.10 to-0.01; P= 0.008) was associated with thinner macular RNFL and CKD (β=-0.62; 95% CI,-1.16 to-0.08; P= 0.024) was associated with thinner average GCIPL. We consistently observed associations between CKD and thinning of RNFL and GCIPL across Asian and White populations' eyes. These findings further suggest that compromised kidney function is associated with RNFL and GCIPL thinning. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Retinal nerve fiber layer and ophthalmic artery blood flow parameters in pseudoexfoliation syndrome and pseudoexfoliative glaucoma

To investigate the relationship between ophthalmic artery (OA) blood flow parameters and retinal nerve fiber layer (RNFL) thickness in eyes with pseudoexfoliation (PEX). We compared PEX eyes without glaucoma (group A, n=53) and those with glaucoma (group B, n=18) with control eyes (group C, n=44). Subsequently, eyes in groups A and B were compared. Finally, OA color Doppler imaging measurements were recorded, and peripapillary RNFL analysis was performed. The total RNFL measurements differed significantly among the groups (P=0.012), being thicker in group C than in group A (P=0.010) and significantly different between group B and groups A and C (both P=0.001). The peak systolic velocity (PSV) and end diastolic velocity (EDV) measurements of groups A and B were lower than those of group C (PSV: P=0.001 and P=0.001, respectively; EDV: P=0.001 and P=0.001, respectively). No significant difference was noted in resistive index (RI) measurements (P=0.370). In group B, significant negative correlations were noted between total RNFL and PSV (r=-0.743; P=0.001) and between total RNFL and EDV (r=-0.691; P=0.001), but not between total RNFL and RI measurements (P=0.548). Pseudoexfoliation syndrome (PXS) with or without glaucoma was associated with a decrease in the PSV and EDV values of the OA. An extensive study may be needed to further explore the role of PXS in OA blood flow parameters. Total RNFL thickness values were lower in eyes with PEX than in those without.

False-positive classification and associated factors in segmented macular layers and retinal nerve fiber layer analysis: Spectralis OCT deviation map study

The rates, patterns and associated factors for false-positive classification of deviation maps by Cirrus optical coherence tomography (OCT) have been reported. However, research on OCT layer-by-layer deviation maps is lacking. We aimed to determine the rates and associated factors for false-positive classification of segmented macular layers and retinal nerve fiber layer (RNFL) deviation maps of Spectralis OCT, and to identify false-positive patterns on segmented macular layers deviation maps. 118 healthy eyes of 118 normal participants who had undergone Spectralis OCT imaging were included. False-positive classification was determined by the area and location of yellow or red color-coded regions on the deviation map. The false-positive rates on the deviation maps were the highest on the ganglion cell layer map, followed by the inner plexiform layer, retinal layer, and RNFL maps. More myopic/less hyperopic refractive error was a factor significantly associated with higher false-positive classification on the RNFL deviation map, and three false-positive patterns were found on the segmented macular layers deviation maps. Spectralis OCT deviation maps should be interpreted carefully to avoid misdiagnosis, especially for eyes with higher degrees of myopic refractive error on the RNFL map, for which purpose, recognizing the characteristic false-positive patterns would be helpful in clinical practice.

Retinal nerve fiber layer thickness and peripapillary vasculature of post-COVID-19 patients with and without olfactory/gustatory dysfunction symptoms.

We aimed to compare retinal nerve fiber layer (RNFL) thickness and peripapillary vessel density values between COVID-19 patients with or without olfactory/gustatory dysfunction symptoms and healthy controls. We evaluated RNFL and radial peripapillary capillary vessel density (RPC-VD) values of 41 patients who had COVID-19 history and age- and gender-matched control group including 31 healthy individuals with optical coherence tomography angiography. First, post-COVID-19 group's and control group's RNFL and RPC-VD values were compared, then post-COVID-19 patients were divided into subgroups according to the presence (subgroup-A) and absence (subgroup-B) of olfactory/gustatory dysfunction symptoms, and same parameters were analyzed for subgroups. Forty-one eyes of 41 post-COVID-19 patients and 31 eyes of 31 age- and gender-matched healthy controls were included in this cross-sectional study. In RNFL analysis, inferior sector thickness was found significantly lower in post-COVID-19 patients by comparison with control group (P = 0.041). In subgroup analyses, COVID-19 patients who first presented with olfactory/gustatory dysfunction symptoms had higher peripapillary and whole image optic disc capillary density (P = 0.011 and P = 0.002) compared to those who had not had these symptoms. Lower RPC-VD and RNFL thickness were detected in COVID-19 patients compared to healthy controls. Higher Disc-VD values were found in COVID-19 patients with chemosensorial dysfunction (CSD) symptoms compared to those who had not had these symptoms probably due to milder disease course in COVID-19 with CSD. Sectorial RNFL attenuation in COVID-19 might have occurred secondary to peripapillary capillary circulation defect.

Peripapillary nerve fiber layer in patients with iron deficiency anemia: A cross-sectional study in a tertiary eye care center in Central India.

The aim of this study is to evaluate the effect of iron-deficiency anemia (IDA) on peripapillary retinal nerve fiber layer (RNFL) thickness using spectral-domain optical coherence tomography (SD-OCT). The study was conducted at tertiary eye care center in Central India. This study was a prospective, cross-sectional, case-control, and observational study. In the present study, 58 eyes of patients with IDA were compared with 58 eyes of healthy individuals. All individuals underwent a thorough hematological, clinical, and ophthalmic examination, followed by peripapillary RNFL analysis using SD-OCT. A total of 116 eyes were included in the study. The average RNFL thickness (RNFLT) in the cases was 97.26 ± 5.96, and 102.32 ± 6.26 (P = 0.005) in controls. There was a significant RNFL loss in the temporal (66.76 ± 6.1, P = 0.02), superior (119.66 ± 10.47, P = 0.01), nasal (73.59 ± 9.52, P = 0.003), and inferior (129.05 ± 10.96, P = 0.001) quadrants in the cases and controls. Serum hemoglobin, iron, ferritin, total iron-binding capacity, and transferrin saturation were lower in the cases (P < 0.05). A positive correlation was observed between average RNFLT and hemoglobin (r = 0.321), iron (r = 0.122), ferritin (r = 0.152), and transferrin (r = 0.190) levels. In patients with IDA, RNFLT was decreased in all quadrants compared to normal healthy individuals. The inferior and nasal RNFL showed a significant decrease in thickness. The presence of myopia, glaucoma, and diabetic and hypertensive retinopathy can exert an additive effect in the thinning of RNFLs and cause significant visual loss; hence, the correction of anemia is essential. There is a pressing need to raise public and health professional awareness of these problems and their prevention, diagnosis, and management.

Ocular toxicity among patients taking anti-tubercular treatment.

Tuberculosis remains a major public health problem in Nepal and anti-tubercular drugs used for the treatment of pulmonary and extrapulmonary tuberculosis can be associated with ocular toxicity. This prospective study aimed to evaluate the incidence of ocular toxicity among patients receiving anti-tubercular therapy and to assess the change in visual functions and ocular imaging before and after use of anti-tubercular therapy. A total of 89 eyes of 45 TB patients taking anti-tubercular therapy were enrolled. Detailed history and examination including best-corrected visual acuity (BCVA), colour vision (Farnsworth D-15t), contrast sensitivity (Pelli-Robson chart), Goldman visual field analysis and spectral domain optical coherence tomography for retinal nerve fibre layer (RNFL) analysis were assessed at baseline and at 6 months after starting anti-tubercular therapy. Visual evoked potential (VEP) was performed in suspected cases. The mean age of the patients was 29.13±14.00 years and 62.2% were males. The mean weight of the subjects was 54.37±10.36 kg, mean daily dosage of ethambutol was 17.91±1.74 mg/day/kg and mean administration duration was 2.71±1.54 months. The incidence of ocular toxicity was 2.24%. Bilateral retrobulbar optic neuropathy occurred in a 27-year female of 55 kg receiving ethambutol (20 mg/kg/day) for 6 months for Pott's spine. Her best-corrected visual acuity in both eyes was reduced to 6/36 from 6/6 and developed non-specific color vision defect, decreased contrast sensitivity, bilateral cecocentral visual field defect and mean decrease in retinal nerve fibre layer thickness compared to the baseline data. In rest cases, a statistically significant decrease in mean retinal nerve fibre layer thickness in both eyes suggested the evidence of subclinical toxicity. Though less common, ethambutol toxicity can occur in patients under anti-tubercular therapy in the form of retrobulbar optic neuritis. Decreased contrast sensitivity and thinning in the mean retinal nerve fibre layer thickness can be the indicator of subclinical toxicity.

Retinal Nerve Fiber Layer Analysis Using Deep Learning to Improve Glaucoma Detection in Eye Disease Assessment

Recently, the development of a rapid detection approach for glaucoma has been widely proposed to assist medical personnel in detecting glaucoma disease thanks to the outstanding performance of artificial intelligence. In several glaucoma detectors, cup-to-disc ratio (CDR) and disc damage likelihood scale (DDLS) play roles as the major objects that are used to analyze glaucoma. However, using CDR and DDLS is quite difficult since every person has different characteristics (shape, size, etc.) of the optic disc and optic cup. To overcome this issue, we proposed an alternative way to detect glaucoma disease by analyzing the damage to the retinal nerve fiber layer (RNFL). Our proposed method is divided into two processes: (1) the pre-treatment process and (2) the glaucoma classification process. We started the pre-treatment process by removing unnecessary parts, such as the optic disc and blood vessels. Both parts are considered for removal since they might be obstacles during the analysis process. For the classification stages, we used nine deep-learning architectures. We evaluated our proposed method in the ORIGA dataset and achieved the highest accuracy of 92.88% with an AUC of 89.34%. This result is improved by more than 15% from the previous research work. Finally, it is expected that our model could help improve eye disease diagnosis and assessment.

Visual prognosis after transsphenoidal surgery for pituitary adenoma and its relationship with retinal nerve fibre layer thickness

AbstractPurpose: To report a case of pituitary adenoma showing the prognostic correlation between retinal nerve fibre layer analysis by OCT and the final postoperative visual result.Methods: A 55‐year‐old female patient with loss of visual acuity in the right eye. During the clinical study a pituitary adenoma was found. OCT showed greater involvement of the retinal nerve fibre layer of the right eye. It was decided to perform surgery to remove the adenoma.Results: A greater improvement is obtained in the left eye than in the right eye after surgery. This result was expected according to the range of involvement shown in the pre‐surgical OCT.Conclusions: OCT is a rapid, non‐invasive, quantitative and objective method for measuring this parameter, which is why this tool has been shown to be fundamental in the follow‐up of these patients and in making decisions such as the appropriate time to operate. The greater the involvement of the retinal nerve fibre layer, the worse the visual prognosis of each eye.

Retinal nerve fiber layer and ganglion cell complex thickness analysis in patients having relative afferent pupillary defect.

To determine the retinal nerve fiber layer (RNFL) thickness and ganglion cell complex (GCC) thickness in patients having relative afferent pupillary defect (RAPD) measured by optical coherence tomography (OCT). This cross-sectional study was conducted on 30 patients with posterior segment disease and glaucoma presenting with RAPD. The control group comprised 30 patients with the aforementioned diseases without RAPD. RAPD was graded using neutral density filters placed over the unaffected eye. Peripapillary RNFL thickness and macular GCC were measured using the Cirrus HD-OCT machine. There were 45 males and 15 females. There was a statistically significant (P < 0.05) difference in the mean of average RNFL thickness in patients having RAPD (64.73 ± 15.16 μm in the affected eyes) as compared to sick control (82.73 ± 11.33 μm in the affected eyes). It was further observed that there was a decrease in RNFL thickness with advancing grades of RAPD. There was a statistically significant (P < 0.05) difference in the mean of average GCC thickness in patients having RAPD (51.57 ± 14.96 μm in the affected eyes) as compared to sick control (76.36 ± 8.06 μm in the affected eyes). Our study suggests that there is a significant reduction in RNFL thickness and GCC thickness in RAPD patients as compared to the sick control group.

Choroidal thickness and retinal nerve fiber layer analysis in chronic spontaneous urticaria

Aim: In this study, we investigated the effects of chronic spontaneous urticaria on the choroid and retinal nerve fiber layer.&#x0D; Material and Method: The patient group consisted of newly diagnosed 54 chronic spontaneous urticaria (CSU ) patient and the control group consisted of 54 healthy volunteer. Choroidal and retinal nerve fiber layer (RNFL) thickness measurements were performed with Cirrus HD-OCT (Carl Zeiss Meditec Inc., Dublin, CA, USA) 30 minutes after pupil dilation with 0,5% tropicamide.&#x0D; Results: In the patient group, nasal choroidal thickness (NCT) was 290.11±43.16 μm, subfoveal choroidal thickness (SFCT) was 339.17±37.709 μm, temporal choroidal thickness (TCT) was 296.00±42.859 μm, mean choroidal thickness (MCT) was 308.33±35.923 μm and RNFL thickness was 91.11±7.393 μm. NCT was 248.42±35,742 μm, SFCT 276.56±40.04 μm, TCT 253.69±37.384 μm, MCT 259.50±32,986 μm and RNFL thickness 92.19±8.719 μm in the control group. When we examine the p value, it is seen that both groups are similar to each other in terms of RNFL thickness (p=0.326), while there is a significant thickening in all choroidal regions of patients with CSU, including NCT, SFCT, TCT, MCT (p=0.000, p=0.000, p=0.000, p=0.000, respectively). &#x0D; Conclusion: The choroid is affected in CSU and choroidal thickness can be a noninvasive method that can be used in diagnosis CSU. However, studies of longer disease durations may provide more illuminating information about CSU and choroid and RNFL.

Evaluation of ganglion cell complex and retinal nerve fiber layer in children with spina bifida using optical coherence tomography

PurposeSpina bifida (SB) is a congenital disorder caused by the incomplete fusion of the embryonic neural tube during spinal cord development. In this study, we used Spectral Domain Optic Coherence Tomography (SD-OCT) for retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) analyses and compared the results of healthy children and SB patients in a similar age group. MethodsOur study was planned prospectively and conducted between June 2017 and July 2019. One hundred eyes of 50 participants, consisting of 28 SB patients and 22 healthy children were included. In all cases, RNFL and GCC measurements were undertaken using SD-OCT. The circumpapillary RNFL analysis was conducted by examining the circular area of 3.45 mm in diameter around the centre of the optic disc. GCC parameters were determined with MM7 protocols by taking 15 vertical sections from a 7-mm macular square centred in the fovea. ResultsThe mean GCC thickness of the participants was 91.120 ± 5.224 µm in the control group and 91.696 ± 7.410 µm in the SB group. The difference between the two groups was not statistically significant (p > 0.05). The mean RNFL thickness was 102.499 ± 11.250 µm in the control group and 99.549 ± 15.235 µm in the SB group. The mean RNFL thickness of the patients in the SB group was lower than that of the control group, but the difference was not statistically significant (p > 0.05). ConclusionsIn this study, the lack of a statistically significant difference in the RNFL and GCC values between the SB and control groups can be attributed to successful clinical management.