Retinal Nerve Fiber Layer Measurements Research Articles

Long term effect of panretinal photocoagulation on retinal nerve fiber layer parameters in patients with proliferative diabetic retinopathy.

PURPOSE:This study aimed to evaluate the long-term effect of panretinal photocoagulation (PRP) on the retinal nerve fiber layer (RNFL) in patients with proliferative diabetic retinopathy (PDR).METHODS:This was a prospective longitudinal cohort study examining 42 eyes of 42 patients with PDR undergoing PRP. Peripapillary RNFL thickness (RNFLT) was measured using spectral-domain optical coherence tomography at baseline, 1 year, and 3 years following PRP.RESULTS:The mean “average RNFLT” was 89.88 ± 14.26 μm at baseline, 85.75 ± 11.36 μm at 1-year follow-up, and 83.33 ± 11.96 μm at 3-year follow-up. There was a statistically significant difference in the average RNFL thickness at baseline and 1 year and 3 years after PRP. At 1-year follow-up, superior, inferior, and nasal RNFL measurements reduced significantly from baseline (P < 0.01). The reduction in RNFL remained statistically significant for superior and inferior quadrants 3 years after PRP.CONCLUSION:PRP causes a reduction in RNFL thickness until 3 years after the procedure. Caution should be exercised while interpreting peripapillary RNFL thickness scans in patients who have undergone PRP for diabetic retinopathy.

Clinical, ophthalmological, imaging and genetic features in Brazilian patients with ARSACS

BackgroundAutosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an important form of inherited ataxia with a varied clinical spectrum. Detailed studies of phenotype and genotype are necessary to improve diagnosis and elucidate this disorder pathogenesis. OBJECTIVE AND METHODS: To investigate the clinical phenotype, retinal architecture, neuroimaging features and genetic profile of Brazilian patients with ARSACS, we performed neurological and ophthalmological evaluation in thirteen Brazilian patients with molecularly confirmed ARSACS, and examined their mutation profiles. Optical coherence tomography protocol (OCT) consisted in peripapillary retinal nerve fiber layer (RNFL) measurement and qualitative analysis of perifoveal scans. Neuroimaging protocol accessed the frequency of atrophy in cerebellum, corpus callosum and parietal lobe, brainstem signal abnormalities, and posterior fossa arachnoid cysts. We reviewed the literature to delineate the ARSACS phenotype in the largest series worldwide. RESULTS: All patients had ataxia and spasticity, and 11/13 had peripheral neuropathy. Macular microcysts were present in two patients. Peripapillary striations, dentate appearance of inner retina and papillomacular fold were found in eleven cases. All individuals exhibited thickening of RNFL in OCT. The most frequent radiological signs were cerebellar atrophy (13/13), biparietal atrophy (12/13), and linear pontine hypointensities (13/13). Genetic analysis revealed 14 different SACS variants, of which two are novel. CONCLUSION: Macular microcysts, inner retina dentate appearance and papillomacular fold are novel retinal imaging signs of ARSACS. Ophthalmological and neuroimaging changes are common findings in Brazilian patients. The core clinical features of ARSACS are ataxia, spasticity and peripheral neuropathy with onset predominantly in the first decade of life.

Optical coherence tomography is a useful tool in the differentiation between true edema and pseudoedema of the optic disc

PurposeTo assess the usefulness of spectral-domain optical coherence tomography (SD-OCT) peripapillary retinal nerve fiber layer (RNFL) thickness measurement in discriminating early phase optic disc edema (ODE) from pseudoedema (PODE).MethodsHospital-based, multicenter, cross-sectional study involving external patients referred for recent identification of “presumed ODE”. Patients underwent SD-OCT optic nerve head (ONH) RNFL thickness measurement at their first evaluation. In 155 of these, the causative etiology was subsequently ascertained and the respective eyes (one per patient) were assigned to the ODE (95 eyes) or PODE (60 eyes) group. Admission SD-OCT data were retrieved and used for the analysis. ROC curve analysis was used to calculate specificity, sensitivity and predictive value (PV) of the RNFL values.ResultsThe PODE group was significantly younger than the ODE group (p = 0.007). The average and any single-quadrant RNFL thickness was significantly higher in the ODE group compared with the PODE and control groups. The average and the inferior quadrant thicknesses tested the most powerful parameters to differentiate ODE from PODE. A cutoff value of ≥ 110 μm for the average area, or of ≥ 150 μm for the inferior quadrant was associated with maximal sensitivity and specificity with positive PV greater than 80%.ConclusionsThe SD-OCT evaluation of the peripapillary RNFL achieved good specificity, sensitivity and positive PV in discriminating between ODE and PODE. Despite the correct differential diagnosis between these categories still relies on a careful medical history taking and other ancillary testing, we proved the usefulness of SD-OCT RNFL measurement in supporting the diagnostic process.

Retinal nerve fiber layer analysis in cocaine users

Cocaine is a well-known factor of tissue ischemia and may be related to thinning of the inner retinal layers. The present study aimed to evaluate and determine whether cocaine users show retinal nerve fiber layer (RNFL) thinning by means of spectral-domain optical coherence tomography. A group of 17 cocaine users and 18 non-users were recruited for complete ophthalmologic examination. Spectral domain optical coherence tomography (Cirrus OCT) was used to evaluate peripapillary RNFL and macular thickness. The average RNFL measurement in the cocaine users group was significantly thinner compared to the control group. Subjects in the cocaine users group showed significant thinning in the nasal, superior and inferior quadrant. There were no significant differences in macular thickness or in the temporal quadrant between the two groups. This study supports further research with larger sample sizes to precisely determine the effect of cocaine on the RNFL.

Clinical and genetic determinants of chronic visual pathway changes after methanol - induced optic neuropathy: four-year follow-up study

Context: Methanol poisoning induces acute optic neuropathy with possible long-term visual damage.Objective: To study the dynamics and key determinants of visual pathway functional changes during 4 years after acute methanol poisoning.Methods: A total of 42 patients with confirmed methanol poisoning (mean age 45.7 ± 4.4 years) were examined 4.9 ± 0.6, 25.0 ± 0.6, and 49.9 ± 0.5 months after discharge. The following tests were performed: visual evoked potential (VEP), retinal nerve fiber layer (RNFL) measurement, brain magnetic resonance imaging (MRI), complete ocular examination, biochemical tests, and apolipoprotein E (ApoE) genotyping.Results: Abnormal VEP P1 latency was registered in 18/42 right eyes (OD) and 21/42 left eyes (OS), abnormal N1P1 amplitude in 10/42 OD and OS. Mean P1 latency shortening during the follow-up was 15.0 ± 2.0 ms for 36/42 (86%) OD and 14.9 ± 2.4 ms for 35/42 (83%) OS, with maximum shortening up to 35.0 ms. No significant change of mean N1P1 amplitude was registered during follow-up.A further decrease in N1P1 amplitude ≥1.0 mcV in at least one eye was observed in 17 of 36 patients (47%) with measurable amplitude (mean decrease −1.11 ± 0.83 (OD)/−2.37 ± 0.66 (OS) mcV versus −0.06 ± 0.56 (OD)/−0.83 ± 0.64 (OS) mcV in the study population; both p < .001).ApoE4 allele carriers had lower global and temporal RNFL thickness and longer initial P1 latency compared to the non-carriers (all p < .05). The odds ratio for abnormal visual function was 8.92 (3.00–36.50; 95%CI) for ApoE4 allele carriers (p < .001). The presence of ApoE4 allele was further associated with brain necrotic lesions (r = 0.384; p = .013) and brain hemorrhages (r = 0.395; p = .011).Conclusions: Improvement of optic nerve conductivity occurred in more than 80% of patients, but evoked potential amplitude tended to decrease during the 4 years of observation. ApoE4 allele carriers demonstrated lower RNFL thickness, longer P1 latency, and more frequent methanol-induced brain damage compared to non-carriers.

Investigation of neurodegenerative and inflammatory processes in sleep bruxism

ABSTRACT Objective: The present study aimed to evaluate the anxiety and optical coherence tomography (OCT) findings in patients with sleep bruxism (SB) and to develop objective measurements to assess the neurodegenerative and inflammatory processes associated with this disease. Methods: A group of 40 SB patients were compared with a control group consisting of 40 healthy individuals (without SB). Anxiety results and the OCT measurements of retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), and choroidal thickness were assessed in both groups. Results: Anxiety values in the bruxism group were significantly higher than those in the control group. The measurements of RNFL, IPL, and GCL in the bruxism group were significantly lower than the control group, whereas the choroidal thickness was significantly higher. Conclusion: According to literature, this is the first study that analyzed the changes in the retinal structures in bruxism, which revealed that SB is a neurodegenerative and inflammatory process.

Two-year outcomes of a pilot glaucoma suspect telemedicine monitoring program.

PurposeThe purpose of this study was to characterize a pilot program using e-health to monitor glaucoma suspects in a large integrated health system.MethodsA retrospective chart review of patients enrolled in the first 2 years of a new glaucoma suspect telemedicine monitoring program was conducted. Patients were enrolled in the program after being diagnosed as glaucoma suspects in the regular clinic setting and were eligible for the program if they had better than 20/40 vision, intraocular pressure (IOP) <25 mmHg, a normal baseline visual field, and an optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) without clear evidence of glaucomatous optic nerve damage. Patients were followed annually thereafter with measurements of vision, IOP, and OCT RNFL, which were reviewed at a centralized telemedicine reading center. Patients were retained within the program unless there was evidence of disease progression, in which case they were referred to an ophthalmologist for further evaluation. The first 100 patients received a survey assessing their satisfaction with the program after their first visit. The number of patients who adhered to follow-up recommendations, who were referred to an ophthalmologist for additional evaluation, and who began on IOP-lowering medications was evaluated.ResultsA total of 225 patients were enrolled in this program. Of eligible patients, 97.3% attended their 1-year follow-up visit and 92.5% attended their 2-year follow-up visit. Over the course of 2 years, five patients were referred for further clinic evaluation due to concern for progressive RNFL loss, of which two were started on IOP-lowering medications. No patients were referred to the clinic for vision loss or elevated IOP. In all, 87% of patients said that they would be extremely or quite likely to recommend the program to a friend. More than 80% of patients said that the program was extremely or very helpful, convenient, and professional.ConclusionThis novel telemedicine program for monitoring low-risk glaucoma suspects achieved high patient retention. Significant disease progression was rare with a few patients requiring referrals back to the clinic setting or initiation of IOP-lowering therapy. Telemedicine is a promising method to follow patients who are glaucoma suspects.

A Common Glaucoma-risk Variant of SIX6 Alters Retinal Nerve Fiber Layer and Optic Disc Measures in a European Population: The EPIC-Norfolk Eye Study.

A common missense variant in the SIX6 gene (rs33912345) is strongly associated with primary open-angle glaucoma (POAG). We aimed to examine the association of rs33912345 with optic disc and retinal nerve fiber layer (RNFL) measures in a European population. We examined participants of the population-based EPIC-Norfolk Eye Study. Participants underwent confocal laser scanning tomography (Heidelberg Retina Tomograph II, HRT) to estimate optic disc rim area and vertical cup-disc ratio (VCDR). Scanning laser polarimetry (GDxVCC) was used to estimate average RNFL thickness. The mean of right and left eye values was considered for each participant. Genotyping was performed using the Affymetrix UK Biobank Axiom Array. Multivariable linear regression with the optic nerve head parameter as outcome variable and dosage of rs33912345 genotype as primary explanatory variable was used, adjusted for age, sex, disc area, axial length, and intraocular pressure. We further repeated analyses stratified into age tertiles. In total, 5433 participants with HRT data and 3699 participants with GDxVCC data were included. Each "C" allele of rs33912345 was associated with a smaller rim area (-0.030 mm [95% CI -0.040, -0.020]; P=5.4×10), a larger VCDR (0.025 [95% CI 0.017, 0.033]; P=3.3×10) and a thinner RNFL (-0.39 μm [95% CI -0.62, -0.15]; P=0.001). The RNFL association was strongest in the oldest age tertile, whereas rim area and VCDR associations were strongest in the youngest and oldest age tertiles. The protein-coding SIX6 variant rs33912345, previously associated with POAG, has a functional effect on glaucoma-associated optic nerve head traits in Europeans.

Prevalence of Glaucoma among High Myopia

Background: Glaucoma is an optic neuropathy that is characterized by the selective loss of retinal ganglion cells and their axons, which manifests as the loss of the retinal nerve fiber layer (RNFL). Numerous studies have shown that the extent of RNFL damage correlates with the severity of functional deficit in the visual field (VF), and that RNFL measurement by optical coherence tomography (OCT) has good sensitivity for the detection of glaucoma. Purpose: To assess the prevalence of glaucoma among high myopic patients and the association between them using standard automated perimetry (SAP) and optical coherence tomography (OCT). Patients and Methods: A prospective observational randomized cross sectional study included a total of 80 eyes with high myopia, in the period from November 2017 to April 2018. Results: This cross sectional study included 44 subjects with 80 eyes regarding high myopia using the outpatient services of the Qlawoon Hospital, Cairo, who satisfied the inclusion and exclusion criteria between November 2017 and April 2018 aiming to determine the prevalence of glaucoma in high myopic patients. Conclusion: RNFL thickness mean is; for average thickness is 86.37, for superior thickness is 90.06 and for inferior thickness is 82.68 a highly significant P-value.

Retinal nerve fiber layer thickness after laser-assisted subepithelial keratomileusis and femtosecond LASIK: a prospective observational cohort study.

PurposeBased on the assumption that high levels of intraocular pressure (IOP) during femtosecond laser-assisted in situ keratomileusis (FS-LASIK) may compromise the retinal nerve fiber layer (RNFL), newer femtosecond platforms that operate without causing significant IOP elevation have been developed in recent years. However, this assumption has not been adequately tested. The aim of the current study was to evaluate possible changes in RFNL thickness in nonglaucomatous myopic patients undergoing FS-LASIK using the 60 KHz IntraLase® device that significantly elevates the IOP for an appreciable period of time vs an advanced surface ablation technique (laser-assisted subepithelial keratomileusis, LASEK) that does not induce any IOP elevation.MethodsThis was a prospective, observational, controlled cohort study. One randomly selected eye of 114 consecutive eligible patients was analyzed. Inclusion criteria were myopia up to -6.00 diopters and astigmatism up to -2.00 diopters. As clinically indicated, 50 patients underwent LASEK and 64 underwent FS-LASIK. The RNFL thickness was determined with a spectral-domain optical coherence tomography device preoperatively and 3 months postoperatively by the same masked observer.ResultsThere was no significant difference in preoperative refractive error, age, or sex between the groups. Preoperatively, central corneal thickness was significantly lower in the LASEK group (529.1±36.1 vs 562.4±31.6 µm, P=0.001). For the LASEK group, there was no significant difference between preoperative and postoperative RNFL thickness in the studied sectors (superior-temporal, temporal, inferior-temporal, average). For the FS-LASIK group, compared to preoperative RNFL measures, statistically significant thicker postoperative values were found for the average RNFL (mean difference: 0.67 µm, 0.7% increase, P=0.008) and the inferior-temporal sector (mean difference: 0.92 µm, 0.6% increase, P=0.02).ConclusionLASIK with a femtosecond platform that induces high intraoperative IOP did not cause RNFL thinning. The observed differences between preoperative and postoperative values are below the axial resolution limit of optical coherence tomography devices.

Retinal Ganglion Cell Topography in Patients With Visual Pathway Pathology.

To investigate and quantify the impact of intracranial lesions at different locations within the visual pathway on the ganglion cell layer-inner plexiform layer (GCL-IPL) complex and the retinal nerve fiber layer (RNFL). Patients with intracranial lesions affecting the optic chiasm (Group I) or the optic tract and/or lateral geniculate nucleus (Group II) were included. All patients received kinetic visual field assessment and underwent spectral domain optical coherence tomography. Peripapillary and papillomacular bundle (PMB) RNFL and macular GCL-IPL thickness in 4 perifoveal areas were measured and compared with normal values derived from 52 age-matched healthy control subjects. Z-scores for each parameter of every patient were calculated and compared with the normative data. Z-scores less than -2.0 (e.g., -2.5) were considered as being statistically significant. Twenty-two patients (Group I and II: 13 and 9, respectively) were included. Ten of 13 patients in Group I showed significant binasal GCL-IPL thinning, with associated temporal sector thinning in 8 patients. In Group II, all 9 patients showed significant reduction of the GCL-IPL corresponding to the homonymous visual field defect, but only 4 demonstrated RNFL thinning. Contralateral RNFL thinning within the PMB clinically similar to bow-tie atrophy was evident in all patients in Group II. GCL-IPL and RNFL thinning varied in severity from mild (isolated PMB RNFL thickness reduction) to severe (bilateral asymmetrical reduction of PMB RNFL associated with asymmetric, predominantly nasal reduction of GCL-IPL) in Group I. Clinical abnormalities in patients with visual pathway lesions are more likely to demonstrate abnormalities of GCL-IPL than global peripapillary RNFL thickness. However, PMB thickness measurement appears to be a valuable tool to detect abnormalities of the anterior visual pathways. If peripapillary RNFL measurements are performed in such patients, PMB thickness should be considered the most useful quantitative parameter.

Optic Nerve Head Drusen: The Relationship Between Intraocular Pressure and Optic Nerve Structure and Function.

To determine whether at the time of diagnosis, the intraocular pressure (IOP) in patients with optic nerve head drusen (ONHD) correlates with the perimetric mean deviation (PMD) and the mean retinal nerve fiber layer (RNFL) thickness on optical coherence tomography (OCT). This retrospective chart review included adults with ONHD from 2 academic medical centers. Inclusion criteria were age older than 18 years, definitive diagnosis of ONHD, measurement of IOP, and an automated visual field (VF) within 3 months of diagnosis. Exclusion criteria were unreliable VFs, use of IOP-lowering therapy, and visually significant ocular comorbidities. Data were collected from the initial visit. Age, IOP, method of diagnosis of ONHD, mean RNFL thickness, and PMD were recorded. Multiple and logistic regression models were used to control for potential confounders in statistical analyses. Chart review identified 623 patients, of which 146 patients met inclusion criteria. Mean age was 44.2 years (range: 19-82 years). Average PMD of 236 eyes was -5.22 dB (range, -31.2 to +1.21 dB). Mean IOP was 15.7 mm Hg (range: 6-24 mm Hg). Forty eyes (16.9%) underwent RNFL measurement using OCT; mean RNFL thickness was 79.9 μm (range: 43-117 μm). There was no statistically significant association between IOP and PMD (P = 0.13) or RNFL thickness (P = 0.65). Eyes with ocular hypertension tended to have less depressed PMD than those without (P= 0.031). Stratified analyses of visible and buried subgroups yielded similar results. Lowering IOP in patients with ONHD has been proposed as a means to prevent progression of optic neuropathy. Our study demonstrated that among predominately normotensive eyes, higher IOP was not associated with greater VF loss or thinner RNFL at the time of presentation. This suggests that lowering IOP may not be beneficial in preventing visual loss in normotensive eyes with ONHD.

The Effect of Acute Hypovolemia on the Eye

ABSTRACTIntroduction: To investigate the effects of acute hypovolemia induced by blood donation on the eye.Methods or Study Design: This prospective, observational study included a single eye from each of 48 healthy men between 20 and 40 years of age who had donated 500 ml of blood and 28 eyes of 28 healthy, age- and gender-matched control subjects. The ocular parameters including ocular perfusion pressure (OPP), intraocular pressure (IOP), axial length (AL), central corneal thickness (CCT), choroidal and retinal thicknesses, and retinal nerve fiber layer (RNFL) were measured before blood donation and at 10 min and 1, 2, 3, and 4 h after blood donation.Results: The mean OPP was significantly reduced following blood donation (baseline, 43.4 ± 4.9 vs. 40.8 ± 4.6 mmHg; p = 0.003). The mean subfoveal choroidal thickness (SFCT) was measured as 322.96 ± 76.23, 291.63 ± 77.85, 309.77 ± 75.72, 312.31 ± 75.98, 315.73 ± 75.43, and 317.75 ± 75.73 µm before blood donation, at baseline, 10 min, and 1, 2, 3, and 4 h following donation, respectively [F(2.462, 115.731) = 22.618, p < 0.001]. In the control group, the SFCT was measured as 302.04 ± 32.04, 301.43 ± 35.16, 298.07 ± 37.33, 298.96 ± 39.17, 302.54 ± 39.24, and 301.61 ± 40.41 µm at baseline, 10 min, and 1, 2, 3, and 4 h following donation, respectively [F(2.124, 57.340) = 0.592, p = 0.566]. There was no difference in AL, CCT, RNFL, retinal thicknesses, and IOP measurements performed before and after blood donation (p > 0.05).Conclusions: Acute hypovolemia caused a significant reduction in SFCT which persisted for 3 h. This study may pave way for better understanding of choroidal thickness changes in disease states.

Retinal nerve fibre layer and ganglion cell complex thickness in patients with keratoconus

Background: Keratoconus, a corneal ectasia, is associated with corneal thinning and altered optical media. Consequently, assessment of the visual field, optic nerve head and intraocular pressure measurements may be challenging in patients with keratoconus. Few studies have investigated posterior segment variables including the retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thickness in patients with keratoconus.Aim: To investigate RNFL and GCC thickness in patients with keratoconus.Methods: A comparative quantitative research design was used. The sample consisted of 56 participants (28 with mild, moderate or severe keratoconus, and 28 controls) who accessed the optometry clinic at the University of KwaZulu-Natal. There was an equal distribution of male (n = 14) and female (n = 14) participants in the keratoconus and control groups. Most participants were black (n = 34) or Indian (n = 18). Corneal power and refractive error were assessed with the Oculus Keratograph and subjective refraction respectively. The iVue-100 optical coherence topography device was used to measure RNFL and GCC thickness. Data were analysed by descriptive and inferential statistics.Results: The mean global RNFL thickness was slightly higher in the control group than the keratoconus group for the right (106 µm vs. 99 µm) and left (103 µm vs. 98 µm) eyes but these differences were not significant (p ≥ 0.057). For all RNFL quadrants, slightly lower mean RNFL measurements were found in the keratoconus group. The mean GCC thicknesses were marginally higher (3 µm – 6 µm) in the control group.Conclusion: The RNFL and GCC thickness differences between patients with keratoconus and controls are not clinically significant. Therefore, abnormally reduced RNFL and GCC thickness measurements in patients with keratoconus warrant further investigation for other pathologies specifically glaucoma.

Diagnostic Ability and Structure-function Relationship of Peripapillary Optical Microangiography Measurements in Glaucoma.

The aim of this study was to evaluate the diagnostic abilities of peripapillary optical microangiography (OMAG) measurements in eyes with primary open-angle glaucoma (POAG) and to evaluate the relationship of these measurements with retinal nerve fiber layer (RNFL) thickness and visual sensitivities in different peripapillary sectors. In a cross-sectional study, 97 eyes of 57 control subjects and 101 eyes of 66 POAG patients underwent OMAG and RNFL imaging with optical coherence tomography. POAG was diagnosed on the basis of the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves and sensitivities at 90% specificity of the OMAG and RNFL thickness measurements in different peripapillary sectors were evaluated. Association between OMAG, RNFL thickness, and visual sensitivity measurements were evaluated using fractional polynomial regression models. All OMAG and RNFL measurements were significantly less in the POAG compared with the control eyes. Diagnostic abilities of the best OMAG measurement (inferior sector vessel length density, area under receiver operating characteristic curves: 0.84, sensitivity at 90%, specificity: 65%) were significantly less (P<0.05) than that of the best RNFL measurement (inferior sector RNFL thickness, 0.94 and 81%). Inferior sector vessel length density showed the strongest association with inferior sector RNFL thickness (R=0.66, P<0.001) and the superior sector visual sensitivity loss (R=0.21, P=0.006). The inferior sector OMAG measurements had the best diagnostic ability in glaucoma and the strongest association with RNFL and the visual sensitivity measurements. Diagnostic ability of OMAG measurements, however, were significantly less than the RNFL thickness measurements.

Retinal Nerve Fiber Layer Thickness in Various Retinal Diseases.

Peripapillary retinal nerve fiber layer (RNFL) thickness measurements may be influenced by the range and severity of lesions that are observed distinctively in each retinal disease. We investigated the effects of various macular (central serous chorioretinopathy, macular hole, epiretinal membrane, wet age-related macular degeneration) and retinal vascular (branch retinal vein occlusion, central retinal vein occlusion, diabetic macular edema) diseases on peripapillary RNFL thickness measurements using spectral-domain optical coherence tomography. Six hundred thirty-one eyes from 464 patients with various retinal diseases and 167 controls of similar age were included in this retrospective study. Using spectral-domain optical coherence tomography, we measured the thickness of the macula and the RNFL in both various retinal disease eyes and normal control eyes. Four sectorial and average RNFL thicknesses were compared between each disease and age-matched control eyes. The macular thicknesses were also compared. In the macular disease group, superior (P = .033) and temporal (P = .024) quadrant RNFL thicknesses of central serous chorioretinopathy and temporal (P < .001) quadrant RNFL thicknesses of epiretinal membrane were greater than the age-matched control eyes. No RNFL measurements in macular hole or wet age-related macular degeneration differed significantly from the controls. In the retinal vascular disease group, all sectorial and average RNFL thicknesses of diabetic macular edema and central retinal vein occlusion were greater than those of the controls (all P < .05). In branch retinal vein occlusion, superior (P = .012) and temporal (P < .001) quadrant RNFL thicknesses were greater than those of the controls. Peripapillary RNFL thickness measurements may be influenced by the range and severity of lesions that are observed distinctively in each retinal disease. It also appeared that macular disease had a local effect on RNFL thickness, whereas retinal vascular disease had a diffuse effect on RNFL thickness.

An Assessment of Retinal Nerve Fiber Layer Thickness in Non-Diabetic Obese Children and Adolescents.

Objective:Obesity affects almost all systems in the body. This includes the retinal nerve fibers which may be damaged due to a chronic inflammatory process. To determine changes in retinal nerve fiber layer (RNFL) thickness in non-diabetic children and adolescents using optical coherence tomography (OCT) and to evaluate the relationship between this change, metabolic risk factors and pubertal stage.Methods:Thirty-eight obese and 40 healthy children and adolescents aged 10-18 years were included in the study. RNFL measurements from the optic disk and all surrounding quadrants were obtained using OCT from both eyes of the individuals in the study groups. Correlations between RNFL thickness and age, auxological measurements, pubertal stage, systolic and diastolic blood pressure, homeostasis model assessment-insulin resistance (HOMA-IR) index and lipid values were investigated.Results:A general decrease was observed in RNFL thickness in obese subjects compared to the controls, the decrease being highest in the inferior quadrant, although these differences were not statistically significant (p>0.05). RNFL thickness was negatively correlated with body mass index (BMI) standard deviation score (SDS) in both groups (control group r=-0.345, p=0.029; obese group r=-0.355, p=0.022). Significant negative correlations were determined between diastolic blood pressure, HOMA-IR, low density lipoprotein cholesterol level and RNFL thickness (r=-0.366, p=0.024; r=-0.394, p=0.016; and r=-0.374, p=0.022, respectively) in the obese group, while there was no association between these parameters and RNFL thickness in the control group.Conclusion:In this cross-sectional study, no statistically significant difference in RNFL thicknesses between the obese and control groups was determined. However, RNFL thickness was found to decrease in both healthy and obese children as BMI-SDS values increased. Further prospective studies may be of benefit to determine whether the decrease in RNFL values might become more pronounced on long-term follow-up.

Integrating Macular Ganglion Cell Inner Plexiform Layer and Parapapillary Retinal Nerve Fiber Layer Measurements to Detect Glaucoma Progression

To investigate the temporal relationship among progressive macular ganglion cell inner plexiform layer (GCIPL) thinning, progressive parapapillary retinal nerve fiber layer (RNFL) thinning, and visual field (VF) progression in patients with primary open-angle glaucoma (POAG). Prospective study. One hundred thirty-six POAG patients (231 eyes) followed up for ≥5 years. OCT imaging of the macular GCIPL and parapapillary RNFL and perimetry were performed at ∼ 4-month intervals. Progressive GCIPL and RNFL thinning were determined by Guided Progression Analysis (GPA) of serial GCIPL and RNFL thickness maps. The specificities of GPA were calculated from the proportions of eyes with progressive GCIPL or RNFL thinning in 67 eyes of 36 healthy individuals followed up for ≥5 years. Visual field progression (likely or possible) was determined by the Early Manifest Glaucoma Trial criteria. Hazard ratios for VF progression, progressive RNFL thinning, and progressive GCIPL thinning, as determined by time-varying Cox models. GPA detected 57 eyes (24.7%) with progressive GCIPL thinning and 66 eyes (28.6%) with progressive RNFL thinning at a specificity of 95.5% and 91.0%, respectively. Thirty-five eyes (15.2%) demonstrated progressive RNFL and GCIPL thinning, whereas 53 eyes (22.9%) demonstrated progressive RNFL or GCIPL thinning. Eyes with progressive GCIPL thinning had a higher risk for progressive RNFL thinning (HR, 5.27; 95% confidence interval [CI], 2.89-9.62), whereas eyes with progressive RNFL thinning were also at a higher risk for progressive GCIPL thinning (HR, 2.99; 95% CI, 1.48-6.02), after adjusting for baseline covariates. The HRs for likely and possible VF progression were 3.48 (95% CI, 1.51-8.01) and 2.74 (95% CI, 1.26-5.98), respectively, on detection of progressive GCIPL thinning and 3.66 (95% CI, 1.68-7.97) and 2.54 (95% CI, 1.23-5.21), respectively, on detection of progressive RNFL thinning after adjusting for baseline covariates. Eyes with VF progression were not at risk of progressive RNFL or GCIPL thinning (P ≥ 0.493). Progressive macular GCIPL thinning and progressive parapapillary RNFL thinning are mutually predictive. Because progressive RNFL thinning and progressive GCIPL thinning are both indicative of VF progression, integrating macular GCIPL and parapapillary RNFL measurements is relevant to facilitate early detection of disease deterioration in glaucoma patients.

Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherencetomography in normal and ocular hypertensive subjects.

To evaluate quantitatively the intraobserver reproducibility of measurements of the retinal nerve fiber layer (RNFL) in healthy subjects and an ocular hypertensive population using two nerve fiber analyzers. Sixty eyes of normal (n=30) and ocular hypertensive subjects (n=30) were consecutively recruited for this study and underwent a complete ophthalmologic examination and achromatic automated perimetry. RNFL were measured using scanning laser polarimeter (GDx-VCC) and optical coherence tomography (OCT Model 3000). Reproducibility of the RNFL measurements obtained with both nerve fiber analyzers were compared using the coefficient of variation. In both groups the authors found fair correlations between the two methods in all ratio and thickness parameters. The mean coefficient of variation for measurement of the variables ranged from 2.24% to 13.12% for GDx-VCC, and from 5.01% to 9.24% for OCT Model 3000. The authors could not detect any significant differences between healthy and ocular hypertensive eyes, although in normal eyes the correlations improved slightly. Nev-ertheless, the testretest correlation was slightly better for GDx-VCC than for OCT Model 3000 (5.55% and 7.11%, respectively). Retinal mapping software of both nerve fiber analyzers allows reproducible measurement of RNFL in both healthy subjects and ocular hypertensive eyes, and shows fair correlations and good intraobserver reproducibility. However, in our study, GDx showed a better testretest correlation. (Eur J Ophthalmol 2004; 14: 523-30).

Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness Measurements by Topcon SD-OCT in Myopic Patients.

To evaluate the effect of low-to-moderate myopia on peripapillary retinal nerve fiber layer (RNFL) thickness measured by Topcon SD optical coherence tomography (OCT). Cross-sectional study. Ophthalmology Department, Shifa Foundation Falahee Clinic, over a period of one year starting from June 2015. A total of 43 eyes of 43 patients, having mild to moderate myopic refractive error, were enrolled in the study. Refractive error/spherical equivalent was calculated. RNFL thickness was obtained from all four peripapillary quadrants: temporal, superior, nasal, and inferior; and 12 sub-quadrants using Topcon SD OCT. Pearson correlation coefficients (r) were calculated to evaluate relationships between the RNFL thickness and spherical equivalent (SE) before and after adjustment for ocular magnification. The study included 51.2% females and 48.8% males. Mean age was 30.9 ±6.45 years. Mean axial length was 24.25 ±0.91 mm. Mean SE was -3.25 ±1.93 DS. Mean of average RNFL thickness (with Littmann's correction) was 97.28 ±8.15 µm. Correlation analysis among all subjects showed that the average, mean nasal quadrant, upper nasal, and inferonasal sub-quadrant RNFL thickness had positive correlation with spherical equivalent (r = 0.31, p = 0.045).However, correction of the magnification effect by applying Littmann formula eliminated this effect. In low-to-moderate myopia, RNFL measurements vary with refractive error of the eye. Since ocular magnification significantly affects the RNFL measurement, it should be considered in diagnosing glaucoma.