Changes In Nerve Fiber Layer Thickness Research Articles

The structure-function relationship between multifocal pupil perimetry and retinal nerve fibre layer in glaucoma.

Multifocal pupillographic objective perimetry (mfPOP) is a novel method for assessing functional change in diseases like glaucoma. Previous research has suggested that, in contrast to the pretectally-mediated melanopsin response of intrinsically photosensitive retinal ganglion cells, mfPOP responses to transient onset stimuli involve the extrastriate cortex, and thus the main visual pathway. We therefore investigate the correlation between peripapillary retinal nerve fibre layer (pRNFL) thickness and glaucomatous visual field changes detected using mfPOP. Parallel analyses are undertaken using white on white standard automated perimetry (SAP) for comparison. Twenty-five glaucoma patients and 24 normal subjects were tested using SAP, 3 mfPOP variants, and optical coherence tomography (OCT). Arcuate clusters of the SAP and mfPOP deviations were weighted according to their contribution to published arcuate divisions of the retinal nerve fibre layer. Structure-function correlation coefficients (r) were computed between pRNFL clock-hour sector thickness measurements, and the local visual field sensitivities from both SAP and mfPOP. The strongest correlation was observed in the superior-superotemporal disc sector in patients with worst eye SAP MD < -12dB: r = 0.93 for the mfPOP LumBal test (p < 0.001). Correlations across all disc-sectors were strongest in these same patients in both SAP and mfPOP: SAP r = 0.54, mfPOP LumBal r = 0.55 (p < 0.001). In patients with SAP MD ≥ -6dB in both eyes, SAP correlations across all sectors were higher than mfPOP; mfPOP correlations however, were higher than SAP in more advanced disease, and in normal subjects. For both methods the largest correlations with pRNFL thickness corresponded to the inferior nasal field of more severely damaged eyes. Head-to-head comparison of mfPOP and SAP showed similar structure-function relationships. This agrees with our recent reports that mfPOP primarily stimulates the cortical drive to the pupils.

Assessment of Time Lag Between Blood Flow, Retinal Nerve Fiber Layer Thickness and Visual Field Sensitivity Changes in Glaucoma.

This study investigates the temporal relationship between blood flow changes and alterations in retinal nerve fiber layer thickness (RNFLT) and mean deviation (MD) in individuals with glaucoma. Blood flow, measured by mean blur rate in optic nerve head vessels (MBRv) and tissues (MBRt) using laser speckle flowgraphy (LSFG)-NAVI, was analyzed using structural equation models (SEMs). SEMs assessed whether the previous rate of one parameter predicted the current rate of the other parameter, adjusted for its own rate in the previous time interval. Data from 345 eyes of 174 participants were gathered from visits every six months. Rates of change of both MBRv and MBRt were significantly predicted by their own rate in the previous time interval and by the rate of change of MD in the previous time interval (P < 0.001 and P = 0.043, respectively), but not by the rate of MD in the concurrent interval (P = 0.947 and P = 0.549), implying that changes in MD precede changes in blood flow. Rates of change of RNFLT were predicted by their own previous rate and the rate of change of MBRv and MBRt in either the previous interval (P = 0.002 and P = 0.008) or the concurrent interval (P = 0.001 and P = 0.018), suggesting that MBR may change before RNFLT. The evidence supports a temporal sequence where MD changes precede blood flow changes, which, in turn, may precede alterations in RNFLT.

Impaired brachial flow-mediated dilation may predict choroidal and retinal nerve fibre layer thickness changes in people with obesity

ABSTRACT Clinical relevance Choroidal thickness and peripapillary retinal nerve fibre layer (RNFL) changes are known to occur in obesity. Endothelial dysfunction and systemic atherosclerosis may play a role in the pathophysiology of these differences. Background Flow-mediated dilation (FMD) is reduced in patients with endothelial dysfunction, and the ankle-brachial index is a surrogate marker for atherosclerosis. This study was conducted to examine the relationship between systemic vascular parameters (FMD, and ankle-brachial index), subfoveal choroidal thickness, and peripapillary RNFL thickness in obese individuals. Methods This observational, cross-sectional study involved 108 total participants who were divided into two groups. One group consisted of 54 obese subjects who each had a body mass index of 30 kg/m2 or more. The other control group contained 54 participants who each had a body mass index of 25 kg/m2 or less but higher than 20 kg/m2 . For each participant, only one eye was examined in this study. Subfoveal choroidal thickness, RNFL thickness, ankle-brachial index, and ultrasound measurement of the brachial artery FMD were performed. FMD was categorised according to receiver operating characteristic analysis, and endothelial dysfunction was defined as an FMD ≤ 7.29%. Results Subfoveal choroidal and RNFL thicknesses in the temporal quadrant were significantly lower in the obese group (p < 0.05). Lower mean values of subfoveal choroidal and RNFL thicknesses in the temporal and inferior quadrants were observed in subjects with an FMD ≤ 7.29% (p < 0.05). In people with obesity, FMD was positively correlated with subfoveal choroidal thickness (r = 0.322, p = 0.001), inferior RNFL thickness (r = 0.259, p = 0.007), and temporal RNFL thickness (r = 0.297, p = 0.002). However, the ankle-brachial index was not correlated with obesity. Conclusions Impaired FMD was associated with reduced subfoveal choroidal and RNFL thicknesses in the temporal and inferior quadrants of people with obesity.

Assessment of retinal and choroidal vessel density and nerve fibre layer thickness changes after orbitotomy in patients with severe non-active thyroid orbitopathy: a prospective study.

To evaluate the optical coherence tomography angiogram changes in non-active severe thyroid-related ophthalmopathy patients after cosmetic bone decompression. Eighteen patients (25 eyes) with severe not active not compressive (NANC) TED who were candidates for decompression surgery for cosmetic reasons were included in this study, and a 3 × 3mm macular scan was used to measure vessel density and RNFL thickness. Whole macular vessel density in its superficial, deep and choriocapillaris layers was evaluated. The following data were extracted for each of layers: superior and inferior hemispheres, fovea, parafoveal vessel density, its superior and inferior hemispheres, and temporal, superior, nasal and inferior quadrant. The mean RPC increased postoperatively, which was statistically significant in small vessels of peripapillary area (p-value = 0.045). The mean RNFL thickness decreased after surgery and it was statistically significant in the peripapillary (p-value = 0.032) and Inferior-Hemifield area (p-value = 0.036). The choriocapillaris changes were significant in Superior-Hemifield (p-value = 0.031) and Fovea (p-value = 0.03). Thyroid-associated orbitopathy patients have a tendency to decrease vascular density and correlated with disease activity more than stage of orbitopathy. There was not a strong and even discrepant result in linkage of RNFL thickness and other optic nerve function tests and TED patient status and it is needed to do studies with more epidemiologic power and same methodology of study to be more comparable.

Comparative analysis of retinal photoplethysmographic spatial maps and thickness of retinal nerve fiber layer.

The paper presents a comparative study of the pulsatile attenuation amplitude (PAA) within the optic nerve head (ONH) at four different areas calculated from retinal video sequences and its relevance to the retinal nerve fiber layer thickness (RNFL) changes in normal subjects and patients with different stages of glaucoma. The proposed methodology utilizes processing of retinal video sequences acquired by a novel video ophthalmoscope. The PAA parameter measures the amplitude of heartbeat-modulated light attenuation in retinal tissue. Correlation analysis between PAA and RNFL is performed in vessel-free locations of the peripapillary region with the proposed evaluating patterns: 360° circular area, temporal semi-circle, nasal semi-circle. For comparison, the full ONH area is also included. Various positions and sizes of evaluating patterns in peripapillary region were tested which resulted in different outputs of correlation analysis. The results show significant correlation between PAA and RNFL thickness calculated in proposed areas. The highest correlation coefficient Rtemp = 0.557 (p<0.001) reflects the highest PAA-RNFL correspondence in the temporal semi-circular area, compared to the lowest value in the nasal semi-circular area (Rnasal = 0.332, p<0.001). Furthermore, the results indicate the most relevant approach to calculate PAA from the acquired video sequences is using a thin annulus near the ONH center. Finally, the paper shows the proposed photoplethysmographic principle based on innovative video ophthalmoscope can be used to analyze changes in retinal perfusion in peripapillary area and can be potentially used to assess progression of the RNFL deterioration.

The Evaluation of Peripapillary Retinal Nerve Fiber Layer Thickness Changes in Patients with Retinitis Pigmentosa and Patients with Early-Late Stage Glaucoma

The Evaluation of Peripapillary Retinal Nerve Fiber Layer Thickness Changes in Patients with Retinitis Pigmentosa and Patients with Early-Late Stage Glaucoma

Peripapillary vessel density and retinal nerve fiber layer thickness changes in early diabetes retinopathy.

To perform a quantitative analysis of the peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness changes in patients with early stage of diabetic retinopathy (DR). In this case-control study, swept-source optical coherence tomography angiography (SS-OCTA) imaging was used to examine diabetic and age-matched healthy subjects. The optic disc HD 6×6 mm2 blood flow imaging scan mode was selected. Automatic software was used to measure the peripapillary VD, capillary vessel density (CVD), and RNLF in an optic nerve head (ONH) filed based on the Garway-Heath map. In addition, the correlation between peripapillary VD, CVD, and RNFL was further investigated. The cohort consisted of 32 healthy individuals and 72 patients with diabetes (34 eyes with no DR and 38 eyes with mild-moderate NPDR). Peripapillary VD decreased in the mild-moderate NPDR group compared to the control group in most regions (P<0.05). Peripapillary CVD and RNFL thickness were significantly lower in the mild-moderate NPDR group in the superior temporal (ST) quadrants (P=0.018, P=0.030). In the correlation analysis of each region, the RNFL thickness in the NS region was positively correlated with the peripapillary VD and CVD (r=0.233, P=0.05; r=0.288, P=0.015). In the TI region, the RNFL thickness was positively correlated with the peripapillary CVD (r=0.237, P=0.047). The measurement based on the ONH topographic map may be helpful in detecting functional and structural impairments in DR. The peripapillary VD, CVD and RNFL decrease in early DR, and the RNFL thickness altered in association with the CVD or/and VD in some regions.

Effect of Inconsistent Optical Coherence Tomography Scan Location on Glaucoma Progression Analysis.

Circumpapillary retinal nerve fiber layer (RNFL) thickness change induced by optical coherence tomography (OCT) scan circle location displacement was not completely compensated despite the use of Guided Progression Analysis (GPA), especially when the "R1" registration method was applied. The purpose of this study was to evaluate the effect of inconsistent OCT scan location on glaucoma progression detection using GPA. Eighty-four glaucomatous eyes with at least 4 serial OCT tests were included. To evaluate the ability of OCT GPA to adjust the OCT scan location, an analysis was performed without manipulation (control set), and after the OCT scan of the latest test was intentionally moved inferotemporally (test set). The eyes were classified into the adjustment and nonadjustment groups based on the superior or inferior quadrant RNFL thickness agreement between the control and test sets. When the OCT GPA parameters between the control and test sets were compared, the test set showed a greater superior RNFL thickness and lesser inferior RNFL thickness compared with the control set (P<0.05). The eyes in the nonadjustment group (n=21, 25%) had a lower chance of applying the eye-tracking function (P=0.003) and a higher frequency of the "R1" registration method of OCT GPA (P<0.001) than the adjustment group (n=63, 75%); all eyes with the "R1" method were in the nonadjustment group and all eyes with the "R2" method were in the adjustment group. Inconsistent OCT scan location induced changes in RNFL thickness that were not completely compensated despite the use of OCT GPA, especially when the "R1" registration method was applied. These findings indicates a potential for misidentified glaucoma progression.

Retinal nerve fibre layer and ganglion cell layer thickness changes following intravitreal aflibercept for age-related macular degeneration

Purpose To evaluate the effect of intravitreal aflibercept (IVA) injections on peripapillary retinal nerve fibre layer thickness (RNFLT) and macular ganglion cell layer thickness (GCLT) in neovascular age-related macular degeneration (nAMD) patients during a 1-year follow-up. Methods This is a prospective study including 34 patients who were treated with aflibercept for treatment-naive nAMD. Following a loading phase of 3-monthly aflibercept, re-injections were performed on a pro re nata regimen for 12 months. Best-corrected visual acuity, intraocular pressure, and spectral-domain-optical coherence tomography analysis were performed at baseline and 1 month, 3 months, 6 months, and 12 months following treatment. Peripapillary RNFLT and macular GCLT along with the central macular thickness (CMT) and subfoveal choroidal thickness (SFCT) were evaluated at each visit. Results Mean number of aflibercept injections was 6.0 ± 1.8. Significant thinning was observed at the central macular ganglion cell layer and at 1 mm superior, temporal, and nasal ganglion cell layer compared to baseline at 1-year (p < 0.05). No significant change of RNFLT was shown (p > 0.05). Mean CMT and SFCT were significantly reduced after IVA therapy (p < 0.05, for both). No correlation was found between injection number and GCLT change. Conclusions Intravitreal aflibercept caused significant ganglion cell layer thinning during a 1-year follow-up without any changes in RNFLT. Intravitreal aflibercept itself may have a chance to induce decreased GCLT in nAMD patients.

Retinal nerve fiber layer thickness changes following silicone oil removal: before and after 6 months tamponade

Retinal nerve fiber layer thickness changes following silicone oil removal: before and after 6 months tamponade

Variation in retinal nerve fiber layer thickness at different stages of Leber’s hereditary optic neuropathy in patients with the ND4 G11778A mutation

ABSTRACT Purpose To investigate retinal nerve fiber layer (RNFL) thickness changes at different stages of Leber’s hereditary optic neuropathy (LHON) in patients bearing the ND4 G11778A mutation. Methods Ninety-eight clinically diagnosed, G11778A-positive LHON patients underwent 538 optical coherence tomography (OCT) examinations from September 2015 to September 2017. Patients were grouped based on disease duration at examination. Fifty healthy volunteers underwent 100 examinations as controls. Differences in RNFL thickness were compared across groups. Results During the onset of LHON patients with G11778A mutation, the thickness of nerve fiber layer in temporal quadrant decreased slowly within 1–3 months (p > .05), then entered in the rapid thinning period, which generally lasted until about 12 months of the course of disease (p < .05), and no obvious change occurred in the stable stage (p > .05); The optic nerve fiber layer in other quadrants was usually stayed in a significant thickening period within 1–3 months (p < .05), then entered in the rapid thinning period, which generally lasted until about 24 months of the course of disease (p < .05), and no obvious change occurred in the stable stage (p > .05) . Conclusion In LHON patients with G11778A mutation, the thickness of optic nerve fiber layer in the temporal side will experience slow thinning stage, rapid thinning stage and stable stage; The thickness of optic nerve fiber layer in other directions varies with the course of disease. Generally, it will experience five periods: significant thickening period, swelling period, recovery period, rapid thinning period and stable period.

Long-Term Effects of a Photodisruptive Laser-Induced Traumatic Neuropathy Model.

PurposeTo create a mouse traumatic optic neuropathy (TON) model that is reproducible, reliable, and easy to manipulate with high specificity to retinal ganglion cell (RGC) layer and no mortality. The model will be useful for understanding the pathophysiology of retinal ganglion cell death and for testing neuroprotective therapeutics.MethodsAn Nd:YAG laser was used to generate focal photodisruptive retinal damage. Noninvasive in vivo ophthalmologic imaging technologies such as optical coherence tomography (OCT) and confocal laser scanning ophthalmoscopy (CSLO) were used to longitudinally track the retinal nerve fiber layer (RNFL) thickness and RGC number change, respectively. Immunostaining and pattern electroretinography (PERG) were also used to evaluate structure and functional change after laser injury.ResultsOur ND:YAG laser generates a concussive photodisruptive laser shockwave force which induces focal RGC death in the targeted area. We observed a correlative decrease in RGCs number, RNFL, and PERG function of RGC in the laser zone. The pattern of RNFL thinning and RGC soma loss correlates with the pattern and amount of fluorescence loss on OCT and CSLO images, respectively. The ND:YAG laser does not cause any damage to other layers in the retina nor any side effects including changes in intraocular pressure, corneal edema, and calcification or mortality (which has been observed in other TON models).ConclusionsWe have created a new and novel RGC TON death model that confers no mortality and produces a quantifiable decrease in RGC number and function. The laser targeted regions of the retina correlate with both in vivo imaging by OCT and CSLO and histologically with regions of RGC loss without ophthalmic side effects.Translational RelevanceThis laser-based TON injury model is simple to implement, is reproducible, and is useful for determining the molecular and cellular pathophysiology of TON and RGC death and for testing neuroprotective therapeutics.

Peripapillary vascular density and retinal nerve fibre layer changes in patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a systemic disease which may cause end organ damage. In this study, we aimed to investigate the radial peripapillary capillary (RPC) density and retinal nerve fibre layer (RNFL) thickness changes in patients with COPD. The right eyes of 35 patients with COPD and 35 healthy controls were evaluated with optical coherence tomography angiography (OCTA). RPC density values and RNFL thicknesses were measured and compared. The mean inside disc vascular density and the mean peripapillary vascular density values were lower in the COPD group (p=0.002, p<0.001, respectively). When the peripapillary area was evaluated independently as eight different quadrants, the RPC density values were lower in the COPD group in all of the quadrants except superotemporal and temporal superior quadrants. RNFL was thinner in all quadrants in the COPD group compared to the control group. But this difference was significant only in the nasal superior and inferonasal quadrants (p=0.03, p=0.04, respectively). Although, there was no correlation between the mean RPC density and the mean peripapillary RNFL thickness of the patients, FEV1 values for all patients were found to be correlated with the mean peripapillary RPC density (r=0.406, p=0.015). OCTA may have a potential to be used in the follow-up of COPD patients.

Changes in peripapillary and macular vascular density after laser selective trabeculoplasty: an optical coherence tomography angiography study.

To determine the effect of laser trabeculoplasty on peripapillary retinal nerve fibre layer thickness (RNFL), fovea avascular zone (FAZ), peripapillary and macular vessel density (VD) in glaucoma using with optical coherence tomography angiography (OCT-A). This was a prospective observational study performed at the Glaucoma Research Centre, Montchoisi Clinic, Lausanne, Switzerland. Thirty-seven eyes with primary open-angle glaucoma from 21 patients were included. Optical coherence tomography angiography (OCT-A) scans were performed before laser trabeculoplasty and at 2 and 6 months after the procedure. AngioVue AngioAnalytic (Optovue Inc, Fremont, CA, USA) software was used to analyse the RNFL, FAZ, peripapillary and macular VD. Changes were analysed using mixed models, controlling for intraocular pressure (IOP) and signal strength index (SSI) variations. Mean IOP decreased from 18.5 (±3.7) mmHg at baseline to 15.6 (±2.7) mmHg after 2 months (-15.3%; p < 0.001). No significant changes in RNFL thickness were noted following laser trabeculoplasty. Changes in peripapillary VD were mostly nonsignificant. Parafoveal (p = 0.001) and perifoveal VD (p = 0.025) significantly increased at 2 months, before reverting to near-baseline values at 6 months. No significant changes were observed in foveal parameters. Retinal nerve fibre layer thickness (RNFL) and VD changes were independent from IOP, but SSI had a significant influence on VD. Following laser trabeculoplasty, peripapillary and macular VD temporarily increased before returning to near-baseline values by 6 months. No correlation was found between microvascular fluctuations and IOP, and no significant effect of laser trabeculoplasty on VD or RNFL was observed at 6 months despite persistent IOP reduction. Further research is warranted to understand its exact causes and clinical relevance.

CHANGES IN RETINAL NERVE FIBER LAYER THICKNESS ON HEIDELBERG RETINAL TOMOGRAPHY IN PATIENTS OF PRIMARY OPEN ANGLE GLAUCOMA AFTER TRABECULECTOMY VERSUS ANTI GLAUCOMA MEDICATION

OBJECTIVE: To compare the retinal nerve fiber layer (RNFL) thickness changes in patients of primary open-angle glaucoma after trabeculectomy versus anti-glaucoma medication. METHODS: This quasi-experimental study was conducted from 10th February, 2017 to 28th February, 2018 on 60 patients presenting to the Institute of Ophthalmology, Mayo Hospital, Lahore, Pakistan using non-probability consecutive sampling. Patients were assigned to two equal groups: group A (n=30) patients underwent trabeculectomy while group B (n=30) patients were put on anti-glaucoma medication. Pre-treatment and three months post-treatment RNFL thickness was recorded and then analyzed using SPPSv.18.0. RESULTS: Out of 60 patients, Group A (n=30) had 14 (46.71%) males and 16 (53.31%) females, while Group B (n=30) had 16 (53.31%) males and 14 (46.71%) females. The mean age was 55.901±4.221 and 55.431±3.971 years in Group A and Group B respectively (p=0.661). In age group, 16 (53.31%) each in Group A and Group B were <55 years. Hypertensive status showed 9 (30.01%) and 5 (16.71%) hypertensive patients in Group A and Group B respectively. Mean change in RNFL thickness was 0.028±0.012μ and 0.013±0.007μ in Group A and Group B respectively (p=<0.001). Pre and post-treatment (pre:post) RNFL thickness (μ) in males, females, hypertensive, non-hypertensive, age <55 years, and age ≥55 years was 0.201±0.175μ:0.226±0.155, 0.205±0.159:0.233±0.019, 0.193±0.015:0.223±0.013, 0.206±0.015:0.233±0.018, 0.208±0.015:0.232±0.021, and 0.196±0.016:0.228±0.015 for Group A and 0.211±0.018:0.224±0.019, 0.201±0.015:0.215±0.014, 0.214±0.015:0.226±0.016, 0.205±0.018:0.218±0.017, 0.206±0.017:0.219±0.015, and 0.209±0.019:0.221±0.020 for group B respectively. CONCLUSION: Trabeculectomy increases thickness of retinal nerve fiber layer more than anti glaucoma medication.

Diffusion tensor imaging of visual pathways in patients with acute and chronic optic neuritis

AIM: To investigate diffusion tensor imaging (DTI) evaluations of visual pathways in patients with acute and chronic optic neuritis (ON), and investigate the correlations between visual disability, retinal nerve fiber layer thickness (RNFLT) and diffusion index changes. METHODS: We performed DTI in 26 patients and 13 healthy controls. Patients had acute ON in 17 eyes, chronic ON in 20 eyes and 15 unaffected eyes. In all participants, the visual afferent system was evaluated with neuro-ophthalmological examinations, optical coherence tomography (OCT), visual evoked potential (VEP), orbital and cranial MRI. RESULTS: Fractional anisotropy (FA) in the optic nerves was lower in patients with acute ON and chronic ON than controls (P=0.28). Mean diffusivity (MD) in the optic nerves, was higher in patients with acute and chronic ON than the unaffected eyes of patients and controls (P&lt;0.01). Retinal nerve fiber layer thickness, P100 amplitude and latency and visual acuity (VA) were significantly different between patient and control groups (P&lt;0.01). Optic chiasm MD values were higher in the patient group compared to the control group (P=0.011). FA and MD measured in the optic tracts significantly were different between groups (P=0.032, P=0.013, respectively). In the correlation analysis, fractional anisotropy in the optic nerves was correlated with P100 latency in acute ON (P=0.021). Mean diffusivity was correlated with RNFLT, visual acuity and P100 latency (P&lt;0.05). Fractional anisotropy was correlated with mean diffusivity and visual acuity, and, mean diffusivity was correlated with P100 amplitude and RNLF thickness in chronic ON (P&lt;0.05). Reduction in visual acuity was correlated with increase in mean diffusivity and decrease in fractional anisotropy (P&lt;0.05). CONCLUSION: DTI can demonstrate abnormalities in a tissue that appears normal in orbital MRI. Our results suggested that DTI derived measurements correlate with visual disability and tissue injury and therefore they are important from a clinical point of view and also in understanding the pathological processes.

Trends in the Retinal Nerve Fiber Layer Thickness Changes with Different Degrees of Visual Field Defects.

Purpose To explore the disease progression of primary open-angle glaucoma (POAG) in individuals with different degrees of VF defects by analyzing the trends in retinal nerve fiber layer (RNFL) changes at each stage. Methods A total of 39 patients (77 eyes) were divided into three groups based on the severity of glaucomatous visual field (VF) loss: the first group included patients with mild baseline VF defects (mild group; n = 21 eyes). The second group included patients with moderate VF defects (moderate group; n = 18 eyes). The third group included patients with severe baseline VF defects (severe group; n = 38 eyes). For all patients, slit-lamp biomicroscopy of the anterior and posterior segments and detailed fundus and optic disc inspections were performed, the intraocular pressure (IOP) was measured by Goldman tonometry, best-corrected visual acuity (BCVA) was measured, the RNFL thickness was measured by OCT, and the VF was assessed by the Octopus perimeter. All the groups were followed up postoperatively for 18 months. Results The mean RNFL thickness was recorded for all the visits. Using simple linear regression analysis, we found that the R2 values of the three groups were 0.988, 0.982, and 0.814, respectively, and the slopes of mean RNFL thickness changes for mild, moderate, and severe baseline VF defects were −0.088, −0.082, and −0.015, respectively. Moreover, we used simple linear regression analysis to explore whether and how the speed of RNFL thinning differs across groups. The R2 values of the three groups were 0.982, 0.978, and 0.805, respectively, and the slopes for mild, moderate, and severe baseline VF defects were 0.089, 0.085, and 0.017, respectively. Conclusion The rate of RNFL thinning is linear; RNFL thinning is the fastest in individuals with mild baseline VF defects, followed by those with moderate baseline VF defects. In individuals with severe VF defects, changes in the RNFL thickness do not appropriately reflect the progression of the disease. The clinical trial is registered with ChiCTR2000028975.

Intraocular pressure, ganglion cell complex, and retinal nerve fiber layer changes by optical coherence tomography in pseudotumor cerebri

Objectives The purpose of this study was to evaluate the changes in retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) in idiopathic intracranial hypertension or pseudotumor cerebri (PTC). Patients and methods This cross-sectional comparative study involved 50 patients with PTC (group I) and 50 age-matched and sex-matched normal persons as controls (group II). Retinal nerve fiber thickness is measured using OCT for all studied population and then recorded and collected to be statistically analyzed. Results Visual acuity and best-corrected visual acuity were measured in both groups. Comparison between both groups shows a statistically highly significant difference (P Conclusion RNFL thickness measurements can provide important information regarding retinal axonal loss in patients with papilledema from PTC. Although axonal loss was documented in the chronic phase of papilledema, our findings, to be confirmed in future prospective studies, suggest a possible use of OCT during the treatment of PTC syndrome.

Peripapillary retinal nerve fiber layer thickness changes after panretinal photocoagulation and its relation with visual acuity changes in patients with diabetic retinopathy

Background: Panretinal photocoagulation (PRP) is currently the main treatment for proliferative diabetic retinopathy. Optical coherence tomography (OCT) is a noninvasive method of analyzingin vivo retinal architecture. Objectives: The objective was to evaluate the effect of PRP on peripapillary retinal nerve fiber layer thickness (RNFLT) in patients with diabetic retinopathy using OCT and to correlate peripapillary RNFLT changes with the changes in visual acuity (VA). Materials and Methods: This is a prospective study including eighty eyes of eighty patients with proliferative diabetic retinopathy (PDR) and severe non-PDR. PRP was done with frequency-doubled Nd: YAG (532 nm) laser. Peripapillary RNFLT was measured by spectral-domain OCT at baseline and 6 months post-PRP and assessed using paired t-test. The baseline VA and changes in VA 6 months post PRP were recorded. The relationship between RNFL loss and changes in VA was assessed using ANOVA and independent t-test. Results: The mean age of the patients was 60 years, with 65% of males and 35% of females. At 6 months post-PRP, there was a significant reduction in average RNFLT with a reduction in all quadrants, except in the temporal quadrant. According to interval changes of VA, the patients were divided into improved (22.5%), unchanged (48.8%), or worsened (28.7%) groups. Improved VA group showed a significant decrease in peripapillary RNFLT. Conclusion: RNFLT reduction following PRP can be due to axonal loss secondary to the direct or indirect effects of PRP. The extremely mild reduction in the temporal quadrant can be due to the sparing of papillomacular bundle during laser treatment.

Changes in retinal nerve fiber layer thickness after panretinal photocoagulation in diabetic retinopathy

Context: Panretinal photocoagulation (PRP) is the gold standard treatment for high risk proliferative diabetic retinopathy. Aim: The evaluation of peripapillary retinal nerve fiber layer (RNFL) thickness changes in eyes undergoing PRP by optical coherence tomography. Materials and Methods: RNFL thickness was measured before PRP, then after PRP by 1, 3, and 6 months, respectively. Results: Mean peripapillary RNFL thickness increased significantly 1 month after P (P = 0.001), then showed insignificant decrease at 3 months' post-PRP (P = 0.1), then it showed significant decrease at 6 months (P = 0.0001) compared to baseline. Conclusions: PRP should be used with a great caution with least number of shots to avoid excessive damage to inner retinal layers.