Nerve Fiber Layer Research Articles

Relationship of Corneal Biomechanics Measured by Corvis ST and Optic Nerve Head Parameters in Healthy Saudi Females.

This study assessed the correlation between corneal biomechanical properties measured with Corvis ST (CST) and retinal nerve fiber layer thickness profile, anterior lamina cribrosa surface depth, and other optic nerve head parameters in healthy Saudi females. This study included 62 eyes (only right eyes) of 62healthy Saudi females aged from 20 to 39 yrs. A complete ophthalmologic assessment was performed for all participants. In addition, corneal biomechanical parameters were measured using CST, and optic nerve head parameters were evaluated using spectral domain optical coherence tomography. This study demonstrated a significant weak positive correlation between circumpapillary retinal nerve fiber layer (cpRNFL) peak angle and only second applanation (A2) length (mm) (r = 0.293, P = 0.021). Also, this study reported a significant moderate negative association between the C/D ratio and radius (r = -.513, P = 0.015). However, there was no significant correlation between corneal biomechanics and ALCSD in this study. This study reported a significant positive correlation between cpRNFL peak angle and A2-length. In addition, the current study documented a significant moderate negative association between C/D ratio and radius. However, there was no significant correlation between ALCSD and the corneal biomechanical properties in this study. Further research is needed to verify the impact of corneal biomechanics on optic nerve head parameters and further investigate its role in the pathophysiology of glaucoma.

Initial Retinal Nerve Fiber Layer Loss and Risk of Diabetic Retinopathy Over a Four-Year Period.

The purpose of this study was to investigate whether the rapid rate of peripapillary retinal nerve fiber layer (pRNFL) thinning in short-term is associated with the future risk of developing diabetic retinopathy (DR). This prospective cohort study utilized 4-year follow-up data from the Guangzhou Diabetic Eye Study. The pRNFL thickness was measured by optical coherence tomography (OCT). DR was graded by seven-field fundus photography after dilation of the pupil. Correlations between pRNFL thinning rate and DR were analyzed using logistic regression. The additive predictive value of the prediction model was assessed using the C-index, net reclassification index (NRI), and integrated discriminant improvement index (IDI). A total of 1012 patients with diabetes (1012 eyes) without DR at both baseline and 1-year follow-up were included in this study. Over the 4-year follow-up, 132 eyes (13%) developed DR. After adjusting for confounding factors, a faster rate of initial pRNFL thinning was significantly associated with the risk of DR (odds ratio per standard deviation [SD] decrease = 1.15, 95% confidence interval [CI] = 1.08 to 1.23, P < 0.001). Incorporating either the baseline pRNFL thickness or its thinning rate into conventional prediction models significantly improved the discriminatory power. Adding the rate of pRNFL thinning further enhanced the discriminative power compared with models with only baseline pRNFL thickness (C-index increased from 0.685 to 0.731, P = 0.040). The IDI and NRI were 0.114 and 0.463, respectively (P < 0.001). The rate of initial pRNFL thinning was associated with DR occurrence and improved discriminatory power of traditional predictive models. This provides new insights into the management and screening of DR.

Impact of transcranial Direct Current Stimulation on stereoscopic vision and retinal structure in adult amblyopic rodents.

The impact of visual deprivation on retinal structure is widely debated. Experimental models, like monocular deprivation through lid suture, provide insights into the consequences of lacking visual experience during development. This deprivation delays primary visual cortex (CV1) maturation due to improper neural connection consolidation, which remains plastic beyond the critical period. However, few studies have used Optical Coherence Tomography (OCT) to investigate structural alterations in the retina of animal models following monocular deprivation. Instead, some studies have focused on the ganglion cell layer using post-mortem histological techniques in amblyopia models induced by monocular deprivation. In this study, we used Cliff test to assess stereoscopic vision and spectral domain optical coherence tomography (SD-OCT) to evaluate retinal changes in an in vivo model of visual deprivation treated with Transcranial Direct Current Stimulation (tDCS). The depth perception test initially revealed differences between individuals with amblyopia and the control group. However, after 8 tDCS sessions, amblyopic subjects matched the control group's performance, which remained stable Additionally, significant changes were observed in retinal structures post-tDCS treatment. Specifically, the thickness of the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) increased significantly in amblyopic eyes (p<0.001). Moreover, significant retinal thickening, including the Nerve Fiber Layer + Ganglion Cell Layer + Inner Plexiform Layer (NFL+GCL+IPL) and the entire retina, was observed post-tDCS treatment (p<0.05), highlighting the critical role of tDCS in ameliorating amblyopia. Additionally, treated animals exhibited reduced thickness in the Inner Nuclear Layer (INL) and Outer Nuclear Layer (ONL). tDCS treatment effectively restores amblyopic individuals' stereoscopic vision, aligning their performance with controls, while impacting retinal structure, highlighting its potential in ameliorating amblyopia's visual deficits.

Accuracy of Diagnosing Optic Neuritis Using DANTE T1-SPACE Imaging.

To evaluate the use of delay alternating with nutation for tailored excitation-prepared T1-weighted turbo spin echo (DANTE T1-SPACE) imaging for diagnosing optic neuritis and to analyze its correlation with clinical findings before and after treatment. Patients diagnosed with optic neuritis or non-arteritic anterior ischemic optic neuropathy (NA-AION) were evaluated at the Ophthalmology Department of Kyoto University Hospital. All patients underwent magnetic resonance (MR) studies before treatment initiation and ophthalmic examinations before and after treatment. Three ophthalmologists independently reviewed the MR scans for abnormalities. The magnetic resonance imaging (MRI) assessments included post-contrast DANTE T1-SPACE, post-contrast volumetric interpolated breath-hold examination (VIBE), and short T1 inversion recovery (STIR) scans. The presence of abnormalities in each sequence was determined. Of 36 eyes from 30 patients, 21 eyes from 17 patients were diagnosed with optic neuritis, and 15 eyes from 13 patients were diagnosed with NA-AION. DANTE T1-SPACE sequences showed better sensitivity for detecting optic neuritis than STIR sequences (100% vs 67%, p = 0.009). VIBE images did not confirm enhancement of lesions in some cases with optic neuritis. No differences were observed among the sequences for NA-AION. Lesion length evaluated by DANTE T1-SPACE sequences was associated with circumpapillary retinal nerve fiber layer thickness at the initial visit, eye pain, and the time interval from symptom onset to MRI scan. Contrast-enhanced DANTE T1-SPACE was better than other sequences of MRI for diagnosing optic neuritis.

Clinical correlation of optic nerve head analysis performed by SD-OCT in children with pseudopapilledema and papilledema

PurposeTo investigate some diagnostic indicators in optic nerve head (ONH) analysis of children with ‘Pseudopapilledema’ and ‘Papilledema’ by Spectral Domain Optical Coherence Tomography (SD-OCT). MethodsMedical records of 52 children with optic disc swelling, who were followed up by the departments of pediatric neurology and ophthalmology between May 2018 and May 2019 were reviewed retrospectively. Cases were classified as group 1 (Papilledema secondary to Idiopathic Intracranial Hypertension) including 54 eyes of 27 cases, group 2 (Pseudopapilledema secondary to bilateral optic disc drusen) including 50 eyes of 25 cases and control group. Three-dimensional imaging of ONH, peripapillary retinal nerve fiber layer (RNLF) thickness, Bruch's membrane opening height in the nasal respectively temporal quadrant (BMHN, BMH-T) levels were measured by SD-OCT and B-mode ocular ultrasonography data of all cases were evaluated. ResultsWhen RNFL levels were compared between groups, nasal RNFL levels were found to be significantly higher in group 1 cases compared to group 2 (p < 0.001). In 3D imaging of the ONH among group 1 patients, the mean height of the apex in disc swelling was significantly higher than that of group 2 (p = 0,024). The apex in disc swelling was mostly observed to be localized at the middle and had a diffuse swelling pattern in group 1; whereas, in group 2, the it was localized mostly at the nasal quadrant. This variation was statistically significant (p < 0.001). When, Bruch's membrane opening height in the nasal respectively temporal quadrant (BMHN, BMH-T) levels were compared, the measurements obtained were found to be significantly higher in group 1 (p = 0,050 and p = 0,003 respectively). ConclusionNasal RNFL values of SD-OCT, Bruch's membrane opening height in the nasal respectively temporal quadrant (BMHN, BMH-T) levels, the location of the apex in disc swelling obtained by 3D analysis of the ONH are found to be potential diagnostic parameters when combined with clinical findings. It is important that the nasal quadrant elevation, where the highest peak in 3D imaging was measured, was higher in the papilledema group. The elevation of the optic disc peak in 3D imaging can be used as a parameter to help clinicians distinguish between optic disc drusen (ODD) and papilledema.

Anterior ischemic optic neuropathy: A complication of hemodialysis

Non-arteritic anterior ischemic optic neuropathy (NA-AION) is a rare complication of chronic hemodialysis in patients with end-stage renal disease. We present an interesting case of a 50-year-old patient on hemodialysis who presented with diminution of vision in the left eye (LE). The pupil showed a relative afferent pupillary defect in LE, and the rest of the anterior segment was within normal limits. A fundus revealed pallid disc edema. LE had color vision defect. Spectral-domain optical coherence tomography showed increased retinal nerve fiber layer thickness at the superior edge of the disc, confirming the diagnosis of NA-AION.

Evaluation of macular and optic nerve head changes by optical coherence tomography angiography in glaucomatous eyes

Background Optical coherence tomography angiography (OCTA) is introduced as a safe, noninvasive, and dye-free technology that provides an assessment of both large vessels and microvasculature of the retina and some parts of the choriocapillaris. Measuring vessel densities using OCTA at both the macula and optic nerve head (ONH) in glaucomatous eyes and comparing them with those of normal eyes will give us an idea about the effect of glaucoma on vessel densities and the role of OCTA in controlling and monitoring glaucoma progression, which remains despite the various medical and surgical treatment options, the second most common reason of blindness worldwide. Aims The current study aimed to assess vessel densities in glaucomatous patients at both the macula and ONH and compare them with vessel densities of normal participants and to assess if OCTA can be useful in the diagnosis and monitoring of the disease. Settings and design Case–control study. Patients and methods The study enrolled 60 patients who were divided into two groups. Group 1 included 30 patients with any type of glaucoma and group 2 included 30 normal participants. OCTA was performed on all of them to assess the macular and ONH vessel densities. Results Glaucomatous patients showed decreased vessel density at the macula and the ONH. The vessel densities at the foveal and all quadrants of parafoveal regions of the macula were decreased when compared with vessel densities of normal participants. Vessel densities at all quadrants of the peripapillary region also decreased when compared with those of normal participants with a strong positive correlation between average peripapillary vessel density and average peripapillary retinal nerve fiber layer thickness. Conclusions Both macular vessel density and ONH vessel density are affected in glaucoma and that may play a role in the diagnosis and follow-up of the disease.

Characteristics of a Large Database of Healthy Eyes From Optometry Practices: Implications for a Real-World Reference Database.

To compare an optical coherence tomography (OCT) real-world reference database (RW-RDB) of "healthy" eyes obtained from optometry practices to a commercial reference database (RDB). OCT scans from 6804 individuals 18years and older were sampled from a larger database tested at 10 optometry practices involved in refractive and screening services. Employing a reading center method, OCT scans from both eyes of 4932 (4.9K) individuals were judged to be of acceptable quality with an absence of pathology. The 4.9K RW-RDB was compared to a commercial RDB with 398 eyes (398 RDB). The means and distributions of global circumpapillary retinal nerve fiber layer (G-cpRNFL) and global ganglion cell layer (G-GCL) thickness, as well as five key anatomical parameters affecting cpRNFL thickness, were not significantly different for all but one parameter (fovea-to-disc distance) and one thickness metric (G-cpRNFL). In both cases, the difference amounted to less than 1.5%. By design, the number of 4.9K RW-RDB eyes 70years and older (724, 14.7%) was greater than for the 398 RDB (40, 10.1%). The error bands on the 5% and 1% quantile regression lines (QRLs) were substantially narrower for the 4.9K RW-RDB. The 398 RDB and 4.9K RW-RDB have similar characteristics and appear to come from a similar population. However, the large size of the 4.9K RW-RDB leads to narrower error bands of the QRLs, which has the potential to increase accuracy. The larger RW-RDB offers the opportunity to better characterize healthy eyes for clinical diagnosis and clinical trials by furthering our understanding of the patterns of artifacts, exploring covariates, developing separate RW-RDBs, and/or improving AI models.

Reproducibility Of Retinal Nerve Fiber Layer And Macular Volume Measurements In Patients Receiving Retinal Protection Pharmacotherapy

Background — High-quality monitoring of the glaucoma plays an important role in the early diagnosis and treatment of glaucoma, for which structural optical coherence tomography (OCT) is used. Technology that increases the repeatability and reproducibility of OCT may differ in different devices, thereby yielding different results. Objective — To assess the effect of the frequency of retinal protection pharmacotherapy courses on quantitative data regarding the macular volume and the thickness of the retinal nerve fiber layer (RNFL) measured by two instruments, SPECTRALIS and OPTOPOL, and also to evaluate the agreement between the data collected by these devices. Material and Methods — We monitored 17 patients (34 eyes) diagnosed with primary open-angle glaucoma in the advanced stage from 2019 to 2023. Group 1 including 9 patients (18 eyes) received a course of retinal protection pharmacotherapy with Retinalamin® at an interval of 3 months, while Group 2 comprising 8 patients (16 eyes) received similar treatment at an interval of 6 months. All observed patients underwent structural OCT on REVO NX (OPTOPOL Technology) and SPECTRALIS devices at the onset of the study, as well as after 3 and 6 months. Results — The agreement between the two devices in measuring RNFL thickness was estimated by the Lin’s concordance correlation coefficient (LCCC): in manual mode, LCCCstart=0.69 (95% CI: 0.51-0.81); while in automatic mode, LCCCstart=0.73 (95% CI: 0.57-0.84). The agreement between the macular volume measurements was as follows: in manual mode, LCCCstart=0.21 (95% CI: 0.21-0.29); while in automatic mode, LCCCstart=0.21 (95% CI: 0.21-0.29). Conclusion — The agreement between the SPECTRALIS and OPTOPOL devices in terms of RNFL thickness should be considered substantial, while in terms of macular volume, it should be classified as fair. As measured in the manual mode, the RNFL thickness in both groups receiving Retinalamin increased, which can be interpreted as a favorable effect of retinal protection pharmacotherapy.

The effect of membrane peeling on the dynamics of anatomical changes in the inner layers of retina after surgical treatment of rhegmatogenous retinal detachment with macular hole

Objective: to determine the effect of membrane peeling on the dynamics of retinal inner layers anatomy changes after surgery for retinal detachment with macular hole. Material and methods. Patients of group 1 (20 patients, 20 eyes) underwent surgical treatment with repair of the rupture using an inverted flap of the internal limiting membrane. Patients of group 2 (20 patients, 20 eyes) did not undergo hole blocking during the first stage of surgery. All patients underwent optical coherence tomography to assess the condition of the inner layers of the retina. Results. One day after surgery, in patients of group 1, the thickness of retinal tissue in the parafoveal zone was 128.2±11.6 nm. In patients of group 2 it was 102.7±6.4 nm (p=0.041). These values remained until the silicone oil was removed. When comparing the indicator of the volume of retinal tissue in the parafoveal zone, there is a decrease in the indicator in patients who underwent membrane peeling, the indicator was 0.645±0.041 mm3, compared with the data of patients of the 1st group, where it was at the level of 0.787±0.52 mm3 (p=0.047). In the temporal quadrant, the difference in indicators persisted until one year after surgery. Conclusion. Membrane peeling leads to damage to the retinal tissue, local defects which can persist up to a year. The outer layers of the retina are damaged throughout the entire area of the macula due to the impact on the supporting plates of the Muller cells and the nerve fiber layer.

High iron in mouse olfactory ensheathing cells at the glia limitans in the olfactory bulb underlies MRI T2* hypointensity

Abstract Brain iron is important for normal function, and aberrantly high iron is often associated with neuroinflammation and neurodegeneration. Oligodendrocytes are a major source of iron in brain as are iron-laden activated macrophages and microglia. T2*-weighted MRI detected a large decrease in signal at the olfactory nerve layer (ONL) in normal young mice over the period of 3 to 12 weeks of age, consistent with iron accumulation in this region. This signal change was most prominent in the inner nerve fiber layer (iNFL). Iron histochemistry, ferritin immunohistology, and electron microscopy showed that there was high iron and ferritin in the olfactory ensheathing cells (OECs) in the iNFL of ONL. The iron concentration in the iNFL was calculated to be approximately 2–3 mM based on MRI T2* relaxivity. The glomerular region near the high-iron iNFL had evidence of neuroinflammation markers of activated microglia and lipofuscin. Lipofuscin was found within the activated microglia as early as 6 weeks. In rats, MRI T2* signal loss in the ONL and high iron levels and lipofuscin were only detected in older rats (11 months) but not in young rats. These results indicate that mouse OECs develop high levels of iron at an early age. It is not clear if this iron is important for mouse OEC function or a result of phagocytic activity of OECs. The relation between iron and inflammation may be interesting to study in these young, healthy mice.

Association between retinal nerve fiber layer thickness and psychiatric disorders: a mendelian randomization study

BackgroundRetinal nerve fiber layer thickness, as a new visual indicator that may help diagnose mental disorders, is gaining attention from researchers. However, the causal relationship between retinal nerve fiber layer thickness and mental disorders is still to be effectively proved.MethodsA bidirectional Two-sample Mendelian randomization analysis was utilized to analyse aggregated data from large-scale genome-wide association studies, we selected genetic loci for retinal nerve fiber layer thickness in independent retinal abnormalities and three prevalent psychiatric disorders (schizophrenia, depression, bipolar disorder) as instrumental variables. The Two-sample Mendelian randomization analysis was mainly performed by inverse variance weighting and weighted median method. The Cochran Q test and leave-one-out sensitivity were used to ensure the robustness of the results. The Mendelian random polymorphism residuals and outliers were used to detect single nucleotide polymorphism outliers, and MR-Egger intercept test was used to test single nucleotide polymorphism horizontal pleiotropy.ResultsIVW showed that retinal nerve fiber layer thickness was positively associated with schizophrenia (OR = 1.057, 95%CI: 1.000-1.117, P < 0.05), in the study of bipolar disorder, MR analysis also suggested a positive causal relationship between retinal nerve fiber layer thickness and bipolar disorder (OR = 1.025, 95%CI: 1.005–1.046, P < 0.05), which indicated possible causal relationships between retinal nerve fiber layer thickness and these two diseases. Depression (OR = 1.000143, 95%CI: 0.9992631–1.001024, P = 0.74) indicated no significant causal association. No reverse causal effects of psychiatric disorders on retinal nerve fiber layer thickness were found.ConclusionsA statistically significant causal relationship between retinal nerve fiber layer thickness and schizophrenia and bipolar disorder has been supported by genetic means, indicating RNFL has potential to aid in the diagnosis of schizophrenia and bipolar disorder.

Optical coherence tomography angiography analysis of the fellow eye in unilateral pseudoexfoliation syndrome

PurposeTo compare the macular and optic disc vascular parameters in the unaffected fellow eyes of subjects with unilateral pseudoexfoliation syndrome (PXS) and controls using optical coherence tomography angiography (OCTA).MethodsThe medical records of 61 eyes of 61 patients were analyzed in a retrospective study. Of these, 30 eyes were unaffected fellow eyes and 31 eyes were control eyes. The vessel density (VD), perfusion density (PD) and foveal avascular zone (FAZ)-related parameters of the superficial capillary plexus (SCP) in the circumpapillary and macular area and the VD and PD of the deep capillary plexus (DCP) in the macular area were measured using OCTA after dilatation and were compared between two groups after adjustment for age, sex and axial length.ResultsThere were no statistically significant differences in sex ratio or mean age, central corneal thickness measurements, refractive errors, intraocular pressures and axial length between both groups (all P > 0.05). In the circumpapillary area, inferior VD and PD in the inner zone, as well as average, temporal, inferior, and nasal VD and PD in the outer zone were significantly reduced in the unaffected fellow eyes with unilateral PXS, while the circumpapillary retinal nerve fiber layer (RNFL) thicknesses were similar between groups. In the macular SCP, VDs were significantly lower in all sectors in the inner area and in the outer zones (p < 0.05 for all), PDs were significantly lower in all sectors (p < 0.05 for all) except the nasal sector of the outer zone (p = 0.003 for average, p = 0.029 for superior sector, p = 0.004 for temporal sector, p < 0.001 for inferior sector), and the FAZ circularity (p = 0.037) were significantly lower in the unaffected fellow eyes with unilateral PXS, whereas macular ganglion cell inner plexiform layer (GCIPL) thickness was similar between the two groups.ConclusionsAlthough circumpapillary RNFL and GCIPL thicknesses were similar between the two groups, VDs and PDs in the circumpapillary and macular SCP and FAZ circularity were significantly lower in the fellow eye of subjects with unilateral PXS.

Nicotine acute impact on RNFL: a comparative analysis of smoking cessation aids including nicotine gum and electronic cigarettes

Purpose To investigate the immediate impact of nicotine consumption on Retinal Nerve Fiber Layer (RNFL) thickness in healthy young individuals, comparing nicotine gum and electronic cigarette (vaping) as delivery methods. Materials and Methods Twenty participants underwent RNFL measurements at baseline, 30, and 60 minutes after consuming 4 mg of nicotine, based on product labeling and specifications. Measurements were obtained using optical coherence tomography (OCT) (Topcon 3D OCT-1 Maestro System). Nicotine was delivered through either nicotine gum or vaping. Results Both nicotine gum and vaping led to a statistically significant increase in RNFL thickness, with no significant difference between the two methods. The analysis revealed that area, time, and visit factors significantly affected RNFL scores. Stratification by smoking type (tobacco, vaping, dual) demonstrated significant effects for area, time, and visit factors, with an interaction effect among these factors. Conclusions The findings highlight the acute impact of nicotine intake on RNFL thickness in young healthy smokers. Researchers and clinicians should account for recent nicotine exposure when evaluating RNFL thickness, particularly within the first hour post-smoking. The observed significant effects warrant further research, especially in older or health-compromised populations, to improve clinical protocols and diagnostic evaluations across different demographics.

Location and Extent of Paravascular Nerve Fiber Layer Clefts in Eyes with Epiretinal Membranes.

Purpose: The clinical use of en face optical coherence tomography (OCT) has revealed nerve fiber layer clefts in the retinal nerve fibers in eyes with macula-centered epiretinal membranes (ERMs). The purpose of this study is to describe the location and the extent of retinal nerve fiber layer (RNFL) clefts in eyes with symptomatic ERMs. Methods: We conducted a retrospective review of 17 individual eyes in 17 patients with symptomatic ERMs and a control group of 10 healthy eyes from 10 subjects who had been examined for unrelated causes. The examinations performed included best-corrected visual acuity, rebound tonometry, fundus photography, structural OCT and angiographic OCT (OCTA) made in the form of 12 × 12 mm angiographic volume scans. Results: Hyporeflective RNFL clefts, seen in 14 out of 17 eyes with ERMs, were sharply demarcated in the en face presentation of slabs extending from the internal limiting membrane through the RNFL or including only the latter. The clefts were capillary-free on OCTA scans and formed depressions of the retinal surface. Most of the clefts were adjacent to and followed the course of the retinal trunk vessels, but clefts were also seen along smaller macular vessels and beyond the retinal vascular arcades. Conclusions: Paravascular RNFL clefts can be observed beyond the vascular arcades and adjacent to small vessels on OCTA block scan data. This suggests that the direction and magnitude of tractional displacement of the inner retina in eyes with epimacular membranes can extend beyond the vascular arcades and add to an improved analysis of abnormal fundus findings.

Use of Tear Substitutes to enhance the Image Quality of the Optic Nerve and Retina by Optical Coherence Tomography

&amp;lt;i&amp;gt;Background &amp; Objectives&amp;lt;/i&amp;gt;: Dry eye disease (DED) has become very prevalent, with the increased usage of internet and video terminals. The present study was carried out to compare the efficacy of tear substitutes in enhancing the signal strength of measurements of optic nerve head, retinal nerve fiber layer and macula by Optical coherence tomography (OCT), and resultant change in image quality. Thus proving the role of artificial tear substitutes in increasing the diagnostic accuracy of Optical coherence tomography (OCT) measurements. &amp;lt;i&amp;gt;Methods&amp;lt;/i&amp;gt;: A double blinded randomized control trial was performed on one hundred and fifty patients needing optical coherence tomography. They were randomly allocated into three groups to receive any one of the three tear substitutes Group 1 –Sodium hyaluronate (Molecular Weight M Wt 799.6g/mol) Group 2 – Poly ethylene glycol (Molecular Weight M Wt 400g/mol), Group -3 Hydroxy Propyl Methyl cellulose (Molecular Weight M Wt 1261.4 g/mol); Measurement of signal strength for optic nerve head, retinal nerve fiber thickness RNFL and sub foveal thickness SFT was done before and after instillation of tear substitutes. Data was analyzed using the Statistical Package for Social Sciences SPSS 22 version software. P value &amp;lt;0.05 was considered statistically significant. &amp;lt;i&amp;gt;Results&amp;lt;/i&amp;gt;: The groups were comparable with respect to mean age and gender distribution. The mean signal strength (SS) of Optic Nerve Head (ONH) evaluation improved in all the groups in both eyes. The increase was the highest in Group II in both eyes. The increase in retinal nerve fiber layer thickness [RNFL] was seen in both eyes in all the groups. Improvement in macular evaluation sub foveal thickness (SFT) was seen in Group II of both eyes and group III in the Left eye. &amp;lt;i&amp;gt;Interpretation and Conclusion&amp;lt;/i&amp;gt;: All tear substitutes improved the quality of the image but the improvement varied with regard to the parameters measured, thus proving artificial tear application is an essential for Optical coherence tomography OCT measurements in persons prone to dry eye This reduces the scope for error due to bad images and thereby the possibility of misdiagnosis of ophthalmic disease.

Longitudinal evaluation of circumpapillary structure-function and vasculature-function relationships in acute and sub-acute nonarteritic anterior ischemic optic neuropathy

PurposeTo investigate the global and regional correlations between longitudinal structure-function (S-F) and vasculature-function (V-F) using circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements, circumpapillary vessel density (cpVD) and the corresponding/final visual outcomes at different stages of nonarteritic anterior ischemic optic neuropathy (NAION). MethodsThirty eyes of 30 patients with acute NAION were included. LogMAR best-corrected visual acuity(BCVA), mean deviation (MD) and visual field index (VFI), cpRNFL thickness and cpVD across different retinal layers were examined at baseline, 2 weeks and 1 month after diagnosis. Potential correlations between the Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) parameters and visual outcomes were investigated in both acute and sub-acute NAION. ResultsSignificant global and regional correlations in S-F relationship were identified exclusively in sub-acute stage (p < 0.05). However, among the OCTA parameters for the acute NAION, the temporal cpVD in superficial vessel complex (SVC) and inner retinal layer (IRL) exhibited positive correlations with corresponding and final visual acuity and visual field outcomes. In the sub-acute stage of NAION, the cpVD of global or temporal section in radial peripapillary capillary (RPC), SVC and IRL were positively correlated with visual outcomes. ConclusionSignificant longitudinal V-F relationships exist both globally and regionally, in acute and sub-acute NAION. The cpVD parameters of the SVC and IRL are potentially valuable for evaluating corresponding and final visual outcomes and highlights the importance of monitoring cpVD over cpRNFL thickness in acute NAION.

Optical Coherence Tomography Angiography Analysis of Peripapillary Choroidal Microvascular Density in normal-tension Glaucoma and Primary open-angle Glaucoma.

Glaucoma patients had a reduction in the inner annulus peripapillary choroidal microvascular density (PCMD) that became worse as the glaucoma severity progressed, which might provide new evidence supporting the vascular theory. To compare PCMD among normal-tension glaucoma (NTG), primary open-angle glaucoma (POAG), and healthy controls using optical coherence tomography (OCT) angiography (OCTA). The study included 40 POAG, 25 NTG, and 33 healthy controls. All subjects underwent OCT and OCTA testing. Inner annulus and outer annulus PCMD, as well as peripapillary vessel density (VD), was calculated. One-way analysis of variance was used to compare the vascular parameters of the three groups. Pearson correlation analysis or Spearman correlation test was used to evaluate the correlation between PCMD and glaucomatous severity factors. The spatial positional relationship between PCMD and corresponding peripapillary retinal nerve fiber layer (RNFL) thickness and visual field (VF) mean deviation (MD) was also assessed. The average and four quadrants of the inner annulus PCMD and peripapillary VD in the two glaucomatous groups were significantly lower than in normal eyes (P<0.05). Strong correlations were found between inner annulus PCMD and VF MD, peripapillary VD, and RNFL in POAG patients. Similarly, the inner annulus PCMD in NTG patients was strongly correlated with peripapillary VD and RNFL (all r>0.5). Strong positional correlations were found between inner superior quadrantal PCMD and RNFL thickness in both POAG and NTG patients (r=0.566, r=0.731, respectively). Likewise, inner inferior quadrantal PCMD exhibited a strong correlation with RNFL thickness in POAG patients (r=0.608). Strong positional correlations were also found between inner superior PCMD and VF MD in both POAG and NTG patients (r=0.589, r=0.622, respectively). Inner inferior PCMD exhibited a moderate correlation with VF MD in both POAG and NTG patients (r=0.487, r=0.440, respectively). The study found that the inner annulus PCMD decreased to varying degrees in NTG and POAG patients. The inner annulus PCMD was closely related to the structural and visual function parameters of glaucoma in both NTG and POAG. Furthermore, inner PCMD demonstrated a spatial correlation with corresponding RNFL thickness and VF MD.

Peripapillary choroidal vascularity of paediatric myopic eyes with peripapillary hyperreflective ovoid mass-like structures.

To assess the peripapillary choroidal vasculature in paediatric myopic patients with and without peripapillary hyperreflective ovoid mass-like structures (PHOMS). This prospective study includes 60 eyes of 60 myopic (spherical equivalent [SE] <-1.00 dioptre [D]) patients with (n = 30) and without (n = 30) PHOMS (PHOMS [+] and PHOMS [-] groups, respectively), and 30 eyes of 30 age- and sex-matched emmetropic children (control group). Peripapillary choroidal parameters, including total choroidal (TCA), luminal (LA), and stromal areas (SA) and choroidal vascularity index (CVI) calculated from vertical and horizontal single-line enhanced depth imaging-optical coherence tomography scans centred on optic nerve head. Peripapillary retinal nerve fibre layer thicknesses were not different between the groups (p > 0.05). In the PHOMS (+) group, TCA, LA and SA were lower, and CVI was higher in all quadrants compared to the control (p < 0.05). However, only the mean TCA and LA in the inferior and nasal quadrants and the mean SA in the nasal quadrant were lower in PHOMS (+) than in PHOMS (-) (p < 0.05). In the PHOMS (-) group, higher CVI was observed in all quadrants except temporal compared to the control group. Although the mean CVI of the PHOMS (+) group was also higher than in the PHOMS (-) group, this difference was not statistically significant. This study indicates that choroidal parameters differ in paediatric myopic patients with PHOMS. Further studies with larger sample sizes are needed to understand the details of choroidal parameters in eyes with PHOMS.

Macular exudate in idiopathic intracranial hypertension affects outer retina and visual acuity

BackgroundOptical coherence tomography (OCT) is suggested as a potential tool for retinal biomarkers in idiopathic intracranial hypertension (IIH). We explored how macular exudate (ME) affects retinal structure in IIH and...