Significant Retinal Nerve Fiber Layer Research Articles

Clinical Relevance of Foveal Location on Retinal Nerve Fiber Layer Thickness Using the New FoDi Software in Spectralis Optical Coherence Tomography

To evaluate the effect of improper foveal location on retinal nerve fiber layer (RNFL) thickness measurements by using the new FoDi software in spectral-domain optical coherence tomography (Spectralis SDOCT). Cross-sectional study with 126 subjects: 66 healthy, 30 early, and 30 moderate glaucomatous eyes. Fast RNFL scans were performed by using the new FoDi technology. The position of the fovea was manually displaced inferiorly after acquisition (producing clockwise torsion of scan circle) and then superiorly (counterclockwise) to generate study sets of images. Differences in RNFL thickness between foveal-guided and alternative scans were analyzed and color changes in sector charts were evaluated. In healthy eyes, placing the fovea inferiorly led to significant RNFL thickness changes in all sectors. Locating the fovea superiorly seemed to have less impact. Early glaucomatous eyes were more susceptible to quantitative changes, but moderate glaucomatous eyes were more susceptible to qualitative changes. Improper fovea disc alignment when using the FoDi software in Spectralis OCT significantly affected sectoral RNFL thickness measurements and color chart representation. As final report of FoDi analysis does not show the foveal position used, careful acquisition is encouraged, so that results are reliable. Otherwise, this technique can easily be misinterpreted and patients could be misdiagnosed.

Optical Coherence Tomography in Patients with Relapsing-Remitting Multiple Sclerosis without Optic Neuritis: A 20-Month Longitudinal Study

Optical coherence tomography is supported and used as a technique for visualisation of neuro-axonal loss in multiple sclerosis, but there are also a few studies expressing the opposite view. The aim of our study was to investigate retinal nerve fibre layer and optic nerve head parameters in patients with multiple sclerosis without a history of prior optic neuritis and symptoms of a new clinical attack during the follow-up for a total of 20-month period. Full ophthalmic evaluation was performed for all of the participants. The baseline retinal nerve fibre layer and macular thicknesses and focal and global loss of macular volume values were significantly lower in the eyes of the patients with multiple sclerosis compared with the healthy controls. No significant change between baseline and follow-up scans were found in all optical coherence tomography parameters in the multiple sclerosis group. Statistical analyses revealed significant retinal nerve fibre layer and macular thickness differences between baseline and second measurements in the controls. No significant difference in percent change between baseline and second measurements was observed between the patient and control groups. We conclude that whereas healthy subjects have an age-related tendency toward a decrease in retinal nerve fibre layer thickness, patients with multiple sclerosis patients are likely to pass through different stages of retinal thinning and thickening due to subclinical optic neuritis and, as a result, we could not detect any statistically significant change between baseline and second measurements in our multiple sclerosis patients.

Predictive value of 1 month retinal nerve fiber layer thinning for deficits at 6 months after acute optic neuritis

Background: Retinal nerve fiber layer (RNFL) loss occurs with multiple sclerosis and after optic neuritis. Vision or RNFL changes at presentation of optic neuritis are not predictive of outcome, but vision loss at 1 month correlates with vision deficits at 6 months. We hypothesized that RFNL thinning at 1 month would predict RNFL loss at 6 months. Methods: We prospectively studied the RNFL by optical coherence tomography (OCT) and scanning laser polarimetry (SLP), and determined the threshold field mean deviation, in 25 subjects with acute optic neuritis over a 6-month period. RNFL values, including the amount of thinning at 1-month, were correlated with 6-month outcome. Results: Baseline visual performance and RNFL values were similar for eyes grouped by 1 month RNFL thinning. Eyes with 1 month RNFL thinning had greater and significant RNFL thinning at 6 months, for all quadrants by OCT and for the nasal and inferior quadrants by SLP. RNFL thinning by OCT and SLP at 1 month correlated with 6-month OCT (r = 0.58; p = 0.006) and SLP (r = 0.59; p = 0.002) RNFL thinning, respectively. Conclusion: Early RNFL loss at 1 month was predictive of the RNFL thinning at 6 months, which corroborated the importance of the 1-month time point for predicting the outcome of an optic neuritis attack.

Can color vision and retinal nerve fiber layer thickness serve as suitable biomarkers in childhood demyelinating disease?

With OCT a better understanding of neurodegeneration in demyelinating disease can be achieved by capturing thinning of the retinal nerve fibre layer (RNFL). On the other hand it is well known that color vision is often affected in these patients. The purpose of this study is to investigate whether there is any association between RNFL thinning and color vision deficiency in children and young adults with demyelinating disease with or without a history of optic neuritis (ON). Thirty young patients (13-28 years) participated in this study. They all had clinically and neuroradiologically confirmed demyelinating disease (which was diagnosed before the age of 16 years) with or without a history of ON. After a thorough clinical examination, they underwent OCT imaging using high-resolution spectral-domain OCT (SD-OCT; Spectralis, Heidelberg Engineering, Germany), measuring RNFL thickness. In addition all patients had a monocular psychophysical color vision evaluation using Ishihara test and Farnsworth-Munnsell hue 100 (FM 100) test. The FM 100 test error score (E.S.) was compared to SD-OCT parameters in eyes with and without ON. All eyes of patients with demyelinating disease showed RNFL thinning compared to normative data. Although thinning in eyes without a history of ON was much smaller, compared to RNFL thinning in eyes after one or more episodes of ON, where significant RNFL thinning was found (P < 0.01). Average E.S. of the whole group of patients was more than 90, ranging from 28 to 584 and was much higher in ON eyes (range, 68-584) compared to eyes without ON (28-56). A strong correlation was found between color vision FM 100 error score and RNFL thickness (P < 0.001). Also other potentially useful biomarkers (such as ERG) need to be analyzed in patients with demielinating disease. Color vision loss and RNFL thinning measured with SD-OCT are in strong correlation in patients with demyelinating disease and can therefore serve as suitable biomarkers of the disease.

Prospective Study on Retinal Nerve Fibre Layer Thickness Changes in Isolated Unilateral Retrobulbar Optic Neuritis

Purpose. To investigate the retinal nerve fibre layer (RNFL) thickness after unilateral acute optic neuritis using optical coherence tomography (OCT). Patients and Methods. This prospective cohort study recruited consecutive patients with a first episode of isolated, unilateral acute optic neuritis. RNFL thickness and visual acuity (VA) of the attack and normal fellow eye were measured at presentation and 3 months in both the treatment and nontreatment groups. Results. 11 subjects received systemic steroids and 9 were treated conservatively. The baseline RNFL thickness was similar in the attack and fellow eye (P ≥ 0.4). At 3 months, the attack eye had a thinner temporal (P = 0.02) and average (P = 0.05) RNFL compared to the fellow eye. At 3 months, the attack eye had significant RNFL thinning in the 4 quadrants and average thickness (P ≤ 0.0002) compared to baseline. The RNFL thickness between the treatment and nontreatment groups was similar at baseline and 3 months (P ≥ 0.1). Treatment offered better VA at 3 months (0.1 ± 0.2 versus 0.3 ± 0.2 LogMAR, P = 0.04). Conclusion. Generalized RNFL thinning occurred at 3 months after a first episode of acute optic neuritis most significantly in the temporal quadrant and average thickness. Visual improvement with treatment was independent of RNFL thickness.

The impact of brimonidine on the loss of retinal nerve fiber layer (RNFL) thickness in glaucoma diabetic patients

AbstractPurpose Brimonidine has proved protective effects on Retinal Ganglion Cells (in animal researches with intravitreal injection), but when used in topical application, its neuroprotective activity has not been unequivocally confirmed. A trail to evaluate potential neuroprotective effect of brimonidine on RNFL in Glaucoma patients.Methods After a retrospective analysis of 1800 patients data, we selected 98, who revealed a significant RNFL thickness loss (21 had Diabetes). We compared the rate of RFNL loss between the group of 53 patients (100 eyes) treated with brimonidine and 45 (90 eyes) treated with other drugs.Results In patients with well‐controlled intraocular pressure (IOP) there is statistically significant relationship between the use of brimonidine and loss of RNFL thickness (p &lt;0.01) and an annual rate of RNFL loss (p=0.01).Conclusion The potentially neuroprotective effect of brimonidine depends on IOP. The higher than normal IOP will limit this potential effect.

Optical coherence tomography assessed retinal nerve fiber layer thickness in patients with Alzheimer's disease: a meta-analysis.

To investigate the difference of retinal nerve fiber layer (RNFL) thickness between Alzheimer's disease patients and normal people, so as to provide clue for the early diagnosis of Alzheimer's disease. The articles on the association of RNFL thickness and Alzheimer's disease were retrieved by searching international and national databases. The qualified articles were assessed by meta analysis with Stata11.0 software. The results were pooled using weighted mean difference (WMD) with a corresponding 95% confidence interval (CI). Totally 7 studies enrolled 324 eyes were included in the meta-analysis. The results of meta analysis showed that in AD patients, there was a significant average RNFL thickness reduction compared with the control group [WMD=-17.561, 95%CI: (-23.971, -11.151)]. There were significant differences in superior, inferior, nasal and temporal RNFL thickness between the two groups. WMD with a 95%CI were [-18.829, 95%CI:(-25.915, -11.743); P<0.05], [-25.775, 95%CI:(-34.304, -17.247); P<0.05], [-16.877, 95%CI: (-29.141, -4.613); P<0.001] and [-14.565, 95%CI:(-28.002, -1.128); P<0.001] respectively. Begg's test and Egger's test did not show significant difference, funnel plot was basically symmetrical, indicating that there was no publication bias existed. There are significant differences in the RNFL thickness in all quadrants between the two groups. RNFL thickness is reduced in AD patients compared with the control group.

Optical coherence tomography shows progressive local nerve fiber loss after disc hemorrhages in glaucoma patients

The aim of this work is to investigate whether optic disc hemorrhages (ODH) lead to significant loss of nerve fibers at the lesion site over time and whether such a loss is reflected by visual field defects corresponding to the affected nerve fiber bundle. In this retrospective study of ten sequential glaucoma patients (ten eyes) with ODH, we used high-resolution OCT circular scans (Spectralis HRA + OCT, Heidelberg Engineering, Heidelberg, Germany) to determine peripapillary retinal nerve fiber layer (RNFL) thickness at the time of ODH presentation and at follow-up visit between 3 and 6 months. Corresponding perimetric data were analyzed for global (mean defect, MD) and localized progression of visual field defects. ODH were mostly located in the inferior quadrant as determined clinically and from fundus photographs. Iterative OCT imaging revealed a significant RNFL reduction in the affected quadrant relative to the respective quadrant in the fellow eye (RNFL change = -2.25 ± 2.69μm vs. 0.75 ± 2.78μm, p = 0.01) within 120 ± 43days. However, only three cases presented with new/progressive nerve fiber bundle defects corresponding to the lesion site within the given follow-up period. ODH lead to a significantly higher RNFL loss at the lesion site relative to the overall structural progression in glaucoma patients. However, this focal change is not generally reflected by respective nerve fiber bundle defects in the time frame investigated.

Retinal Nerve Fiber Layer Thickness in Dominant Optic Atrophy: Measurements by Optical Coherence Tomography and Correlation with Age

To measure the retinal nerve fiber layer (RNFL) thickness by means of optical coherence tomography (OCT) in patients with dominant optic atrophy (DOA). Cross-sectional study. Thirty-three patients from 15 pedigrees with DOA harboring heterozygous mutations in the OPA1 gene and 43 healthy subjects were enrolled. The RNFLs of DOA patients were studied by OCT and compared with those of 43 healthy subjects matched for age and optic nerve head (ONH) size. Retinal nerve fiber layer thickness. Dominant optic atrophy patients revealed a significant RNFL thickness reduction in all quadrants, with a preferential involvement of the temporal and inferior sectors. The progressive decline of RNFL thickness with age was similar to that observed in healthy subjects and was more evident in the 2 quadrants with higher residual amounts of fibers, that is, the superior and the inferior. The temporal quadrant was profoundly depleted of fiber so that the further rate of loss of microns per year is close to zero, whereas the nasal quadrant was spared the most by neurodegeneration. The present findings, taken in conjunction with the authors' previous description of small ONH size in DOA, strongly suggest that patients with this disease are born with fewer optic nerve axons and support the hypothesis that subsequent visual loss depends on further age-related loss of fibers, which also occurs in controls. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Scanning Laser Polarimetry Quantification of Retinal Nerve Fiber Layer Thinning Following Optic Neuritis

Several studies with optical coherence tomography (OCT) have demonstrated thinning of the retinal nerve fiber layer (RNFL) in patients with optic neuritis and multiple sclerosis. Similar studies have not been performed with scanning laser polarimetry (SLP), which relies on different physical phenomena. This study was designed to use SLP to measure axonal loss following a single episode of optic neuritis and to determine if there is a relationship between the degree of axonal loss and the degree of residual visual dysfunction. Twenty-five patients with a single episode of optic neuritis and 15 control subjects were studied with SLP using the GDxVCC device to determine RNFL thickness in relation to visual acuity, visual fields, color vision, visual evoked potentials (VEPs), and previously published OCT data. SLP detected significant RNFL thinning in affected eyes compared to clinically unaffected fellow eyes in patients and in control eyes (P < 0.001). Reduced RNFL thickness was associated with significantly worse logMAR visual acuity, visual field mean deviation, and color vision. RNFL thinning correlated with reduced whole visual field and central visual field measures and VEP amplitudes. Superior and inferior quadrant RNFL thinning was related to corresponding regional visual field loss. There was a scaling factor between SLP and OCT RNFL measurements but only modest agreement. SLP detected functionally relevant axonal loss in eyes affected by optic neuritis. There was a scaling factor between RNFL measurements obtained with SLP and OCT but only modest agreement. Care should therefore be taken when comparing RNFL data from studies using these different devices.

Structural and Functional Assessment in HIV-Infected Patients Using Optical Coherence Tomography and Frequency-Doubling Technology Perimetry

To assess retinal nerve fiber layer (RNFL) and macular thickness using optical coherence tomography (OCT) on HIV-infected patients without ocular manifestations and to correlate these findings with frequency-doubling technology perimetry (FDT). Cross-sectional study. setting: Single center. study population: Seventy-three patients (146 eyes) with clinically normal examination classified in 3 groups: group A, HIV-infected patients with CD4 count <100 cells/mm(3) for at least 6 months; group B, HIV-infected patients with CD4 count >100 cells/mm(3) since diagnosis; and group C, HIV-negative control subjects. observation procedures: Fast RNFL and fast macula scan strategies on Stratus OCT and Humphrey Matrix 24-2 full-threshold program. main outcome measures: OCT RNFL and macular thicknesses and FDT indices (mean deviation [MD], pattern standard deviation [PSD], and glaucoma hemifield test [GHT]). Group A had a significantly thinner average RNFL, temporal outer macula, and inferior outer macula thicknesses when compared to groups B and C (P < .05). Statistically significant differences were observed in the FDT MD between groups A and C (P = .034) and in PSD in group A compared to groups B and C (P = .011). Eyes of HIV patients with GHT and PSD results outside normal confidence limits had thinner average RNFL thickness measures than eyes with results within normal limits in the same group of patients (P < .05). HIV-infected patients with low CD4 count have a significant RNFL and macular thinning. Functional loss detected by FDT is related to RNFL thinning in HIV-infected patients.

Retinal Nerve Fiber Layer Decrease during Glycemic Control in Type 2 Diabetes

Purpose. To assess an effect of glycemic control on retinal nerve fiber layer (RNFL) in type 2 diabetes mellitus. Methods. Thirty-eight eyes of 38 patients with type 2 diabetes undergoing blood glucose regulation were enrolled. All patients were examined at (1) initial visit, (2) 1 month, (3) 2 months, and (4) 4-month after the initial examination. On each occasion, glycosylated hemoglobin (HbA1c) levels and optical coherence tomography (OCT) scanning for RNFL thickness were evaluated. 360 degree circular OCT scans with a diameter of 3.4 mm centered on the optic disc were performed. Results. Significant RNFL decrease was seen in the superior area between initial and 4 months examination (P = .043). The relationship between the changes in HbA1c and the changes in RNFL thickness was observed in superior, temporal, and inferior area (P < .05) at 4 months. Conclusions. This study suggests that the glycemic control affects RNFL within 4 months.

Tracking retinal nerve fiber layer loss after optic neuritis: a prospective study using optical coherence tomography

Introduction Optic neuritis causes retinal nerve fiber layer damage, which can be quantified with optical coherence tomography. Optical coherence tomography may be used to track nerve fiber layer changes and to establish a time-dependent relationship between retinal nerve fiber layer thickness and visual function after optic neuritis. Methods This prospective case series included 78 patients with optic neuritis, who underwent optical coherence tomography and visual testing over a mean period of 28 months. The main outcome measures included comparing inter-eye differences in retinal nerve fiber layer thickness between clinically affected and non-affected eyes over time; establishing when RNFL thinning stabilized after optic neuritis; and correlating retinal nerve fiber layer thickness and visual function. Results The earliest significant inter-eye differences manifested 2-months after optic neuritis, in the temporal retinal nerve fiber layer. Inter-eye comparisons revealed significant retinal nerve fiber layer thinning in clinically affected eyes, which persisted for greater than 24 months. Retinal nerve fiber thinning manifested within 6 months and then stabilized from 7 to 12 months after optic neuritis. Regression analyses demonstrated a threshold of nerve fiber layer thickness (75μm), which predicted visual recovery after optic neuritis. Conclusions Retinal nerve fiber layer changes may be tracked and correlated with visual function within 12 months of an optic neuritis event.

A framework for comparing structural and functional measures of glaucomatous damage

While it is often said that structural damage due to glaucoma precedes functional damage, it is not always clear what this statement means. This review has two purposes: first, to show that a simple linear relationship describes the data relating a particular functional test (standard automated perimetry (SAP)) to a particular structural test (optical coherence tomography (OCT)); and, second, to propose a general framework for relating structural and functional damage, and for evaluating if one precedes the other. The specific functional and structural tests employed are described in Section 2. To compare SAP sensitivity loss to loss of the retinal nerve fiber layer (RNFL) requires a map that relates local field regions to local regions of the optic disc as described in Section 3. When RNFL thickness in the superior and inferior arcuate sectors of the disc are plotted against SAP sensitivity loss (dB units) in the corresponding arcuate regions of the visual field, RNFL thickness becomes asymptotic for sensitivity losses greater than about 10dB. These data are well described by a simple linear model presented in Section 4. The model assumes that the RNFL thickness measured with OCT has two components. One component is the axons of the retinal ganglion cells and the other, the residual, is everything else (e.g. glial cells, blood vessels). The axon portion is assumed to decrease in a linear fashion with losses in SAP sensitivity (in linear units); the residual portion is assumed to remain constant. Based upon severe SAP losses in anterior ischemic optic neuropathy (AION), the residual RNFL thickness in the arcuate regions is, on average, about one-third of the premorbid (normal) thickness of that region. The model also predicts that, to a first approximation, SAP sensitivity in control subjects does not depend upon RNFL thickness. The data (Section 6) are, in general, consistent with this prediction showing a very weak correlation between RNFL thickness and SAP sensitivity. In Section 7, the model is used to estimate the proportion of patients showing statistical abnormalities (worse than the 5th percentile) on the OCT RNFL test before they show abnormalities on the 24-2 SAP field test. Ignoring measurement error, the patients with a relatively thick RNFL, when healthy, will be more likely to show significant SAP sensitivity loss before statistically significant OCT RNFL loss, while the reverse will be true for those who start with an average or a relatively thin RNFL when healthy. Thus, it is important to understand the implications of the wide variation in RNFL thickness among control subjects. Section 8 describes two of the factors contributing to this variation, variations in the position of blood vessels and variations in the mapping of field regions to disc sectors. Finally, in Sections 7 and 9, the findings are related to the general debate in the literature about the relationship between structural and functional glaucomatous damage and a framework is proposed for understanding what is meant by the question, 'Does structural damage precede functional damage in glaucoma?' An emphasis is placed upon the need to distinguish between "statistical" and "relational" meanings of this question.

Objective Analysis of Retinal Function in HIV-positive Children Without Retinitis Using Optical Coherence Tomography

Purpose: To assess the retinal nerve fiber layer thickness in children with human immunodeficiency virus disease without cytomegalovirus retinitis or visual symptoms. Methods: Thirty-eight eyes of 19 human immunodeficiency virus-positive children (group A) with visual acuity of 20/20 or better, normal color vision testing and no ophthalmoscopically detectable disorders were prospectively examined. All subjects of group A had no history of cytomegalovirus retinitis and CD4 counts consistently above 100. Patients in group B (40 eyes of 21 patients) were human immunodeficiency virus-negative age-matched control subjects. Thickness of retinal nerve fiber layer along a 3.4-mm-diameter circle centered on the optic nerve head was evaluated using third-generation optical coherence tomography. CD8 T-lymphocyte count, presence of systemic infection, hemoglobin, hematocrit and serum β-microglobulin levels were also recorded. Results: The mean overall retinal nerve fiber layer thickness in groups A and B were 89.2 ± 24.01 μm and 102.82 ± 29.168 μm (SD) respectively. The difference was considered extremely significant (P < 0.0001). Group A had significantly thinner average nerve fiber layer in temporal, nasal, superior and inferior retinal areas. Conclusions: Significant retinal nerve fiber layer thinning occurs in human immunodeficiency virus-positive children with no visual impairment or ophthalmologic evidence or retinitis.

The effect of ageing on retinal nerve fibre layer thickness: an evaluation by scanning laser polarimetry with variable corneal compensation

To evaluate whether a significant age-related thinning of the retinal nerve fibre layer (RNFL) is measurable by means of scanning laser polarimetry with variable corneal compensation (GDx-VCC) in a sample of healthy eyes. A sample of 324 eyes of 324 healthy subjects (mean age 56 +/- 14 years, range 21-85 years) underwent a complete ophthalmic evaluation, standard automated perimetry and RNFL scan with the GDx-VCC. Temporal-superior-nasal-inferior-temporal (TSNIT), superior and inferior average (SA and IA) values provided on the printout were collected and their mean value averaged from all eyes and also after separating the eyes by gender and by age decades. The values of the three parameters were plotted against age and linear regression was calculated. Ageing is associated with a significant RNFL thinning (0.08 micro, 0.16 micro and 0.12 micro per year for TSNIT, SA and IA, respectively; p < 0.001). Analysis showed a similar association with age decade (p < 0.001 on anova). For the TSNIT average, a 9.5% thinning from baseline values was estimated for a 65-year lifespan. Corresponding values for SA and IA were 16.2% and 11.7%, respectively. Analysis by GDx-VCC confirmed previous reports about significant age-related RNFL thinning. However, a lower rate per year was found, probably because GDx-VCC measurements are much more reliable than those obtained with the previous generation of polarimeters.

Optic nerve atrophy and retinal nerve fibre layer thinning following optic neuritis: Evidence that axonal loss is a substrate of MRI-detected atrophy

Magnetic resonance imaging (MRI) measures of brain atrophy are often considered to be a marker of axonal loss in multiple sclerosis (MS) but evidence is limited. Optic neuritis is a common manifestation of MS and results in optic nerve atrophy. Retinal nerve fibre layer (RNFL) imaging is a non-invasive way of detecting axonal loss following optic neuritis. We hypothesise that if the optic nerve atrophy that develops following optic neuritis is contributed to by axonal loss, it will correlate with thinning of the RNFL. Twenty-five patients were studied at least 1 year after a single unilateral attack of optic neuritis without recurrence, with a selection bias towards incomplete recovery. They had MR quantification of optic nerve cross-sectional area and optic nerve lesion length, as well as optical coherence tomography (OCT) measurement of mean RNFL thickness and macular volume, quantitative visual testing, and visual evoked potentials (VEPs). Fifteen controls were also studied. Significant optic nerve atrophy (mean decrease 30% versus controls), RNFL thinning (mean decrease 33% versus controls), and macular volume loss occurred in patients' affected eyes when compared with patients' unaffected eyes and healthy controls. The optic nerve atrophy was correlated with the RNFL thinning, macular volume loss, visual acuity, visual field mean deviation, and whole field VEP amplitude but not latency. These findings suggest that axonal loss contributes to optic nerve atrophy following a single attack of optic neuritis. By inference, axonal loss due to other post-inflammatory brain lesions is likely to contribute to the global MRI measure of brain atrophy in multiple sclerosis.

Diagnostic Ability of Optical Coherence Tomography with a Normative Database to Detect Localized Retinal Nerve Fiber Layer Defects

To evaluate the diagnostic ability of third-generation optical coherence tomography (Stratus OCT) with a normative database to detect localized retinal nerve fiber layer (RNFL) defects. Cross-sectional study. One eye of each of 55 subjects (43 normal-tension glaucoma and 12 primary open-angle glaucoma subjects) with localized, wedge-shaped RNFL defects by red-free RNFL photographs and corresponding visual field defects (mean deviation, -6.77+/-3.54; range, -1.25 to -9.20 dB). The segments of the borderline and outside normal limits in the RNFL thickness profile of OCT were considered to be significant RNFL defects by OCT and by comparison with their corresponding red-free RNFL photographs. The angular locations and widths of RNFL defects by OCT were compared with those of RNFL defects by red-free RNFL photographs. Sensitivity and specificity of OCT with a normative database to detect the localized RNFL defects. The mean age of the patients was 57.9+/-10.6 years (range, 25-78 years). The overall sensitivity and specificity of the OCT with a normative database for detecting localized RNFL defects were 85.9% and 97.4%, respectively. The OCT with a normative database showed good diagnostic agreement with red-free RNFL photographs (overall kappa value = 0.79). The angular locations and widths of RNFL defects by OCT were highly correlated with those of RNFL defects by red-free RNFL photographs (Pearson correlation coefficient [r] = 0.996 and 0.725, respectively). The OCT with a normative database can detect localized RNFL defects with moderate sensitivity and high specificity, and shows good diagnostic agreement with red-free RNFL photographs.

Scanning laser polarimetry of nerve fiber layer thickness in normal eyes after cataract phacoemulsification and foldable intraocular lens implantation

To assess the effect of cataract phacoemulsification and intraocular lens (IOL) implantation on retinal nerve fiber layer (RNFL) thickness using scanning laser polarimetry (SLP). Eye Clinic, Trieste University, Italy. Forty-eight eyes were evaluated prospectively the day before and 30 days after cataract phacoemulsification and foldable IOL implantation. In each eye, lens opacity grading according to the Lens Opacities Classification System III (LOCS III), and axial length (AL) measurements were performed. Retinal nerve fiber layer thickness was quantified at baseline by means of SLP and anterior segment birefringence compensation was evaluated acquiring macular retardation map (MRM). Acrylic and silicone IOLs were implanted randomly. After surgery, RNFL thickness was reevaluated, and MRM was reacquired. Macular retardation map pattern variations regarding baseline profile were classified into 3 groups: no variation, bow-tie profile enhancement, or attenuation. Distribution of IOL power, AL, and cataract type in the 3 groups was assessed, as were presurgery and postsurgery SLP parameters with mean values (+/-SD) compared by paired t test. Twenty-two eyes (Group 1, 45.8%) showed no MRM variation, 14 (Group 2, 29.2%) an enhancement, and 12 (Group 3, 25%) an attenuation. In Group 1, no significant RNFL thickness variation occurred. In Group 2, variation 10% to 15% was measured, whereas thickening a 8% to 15% thinning appeared in Group 3. Variations occurred irrespective of IOL material, AL, or cataract type. Cataract surgery with IOL implantation was associated with an MRM profile change and RNFL thickness variations in 54.2% of eyes. Variations are probably related to opacified lens removal. A new baseline SLP reading is mandatory after cataract surgery.