Search

Introduction: This study tested whether multiple traumatic brain injuries (TBIs) alter the structure of the Henle fiber layer (HFL) and degrade cell-specific function in the retinas of human participants. Methods: A cohort of case participants with multiple TBIs and a cohort of pairmatched control participants were prospectively recruited. Directional optical coherence tomography and scanning laser polarimetry measured HFL thickness and phase retardation, respectively. Full-field flash electroretinography (fERG) assessed retinal function under light-adapted (LA) 3.0, LA 30 Hz, dark-adapted (DA) 0.01, DA 3.0, and DA 10 conditions. Retinal imaging and fERG outcomes were averaged between both eyes, and paired t-tests or Wilcoxon signed-rank tests analyzed inter-cohort differences. Results: Global HFL thickness was significantly (p = 0.02) greater in cases (8.4 ± 0.9 pixels) than in controls (7.7 ± 1.1 pixels). There was no statistically significant difference (p = 0.91) between the cohorts for global HFL phase retardation. For fERG, LA 3.0 a-wave amplitude was significantly reduced (p = 0.02) in cases (23.5 ± 4.2 µV) compared to controls (29.0 ± 8.0 µV). There were no other statistically significant fERG outcomes between the cohorts. Discussion: In summary, the HFL thickens after multiple TBIs, but phase retardation remains unaltered in the macula. Multiple TBIs may also impair retinal function, indicated by a reduction in a-wave amplitude. These results support the potential of the retina as a site to detect TBI-associated pathology. [ABSTRACT FROM AUTHOR]

IntroductionThis study tested whether multiple traumatic brain injuries (TBIs) alter the structure of the Henle fiber layer (HFL) and degrade cell-specific function in the retinas of human participants.MethodsA cohort of case participants with multiple TBIs and a cohort of pair-matched control participants were prospectively recruited. Directional optical coherence tomography and scanning laser polarimetry measured HFL thickness and phase retardation, respectively. Full-field flash electroretinography (fERG) assessed retinal function under light-adapted (LA) 3.0, LA 30 Hz, dark-adapted (DA) 0.01, DA 3.0, and DA 10 conditions. Retinal imaging and fERG outcomes were averaged between both eyes, and paired t-tests or Wilcoxon signed-rank tests analyzed inter-cohort differences.ResultsGlobal HFL thickness was significantly (p = 0.02) greater in cases (8.4 ± 0.9 pixels) than in controls (7.7 ± 1.1 pixels). There was no statistically significant difference (p = 0.91) between the cohorts for global HFL phase retardation. For fERG, LA 3.0 a-wave amplitude was significantly reduced (p = 0.02) in cases (23.5 ± 4.2 μV) compared to controls (29.0 ± 8.0 μV). There were no other statistically significant fERG outcomes between the cohorts.DiscussionIn summary, the HFL thickens after multiple TBIs, but phase retardation remains unaltered in the macula. Multiple TBIs may also impair retinal function, indicated by a reduction in a-wave amplitude. These results support the potential of the retina as a site to detect TBI-associated pathology.

Background: Retinal nerve fiber layer (RNFL) thickness may reflect cerebral status. Objective: This study assessed the relationship between RNFL thickness and incident all-cause dementia in the European Prospective Investigation into Cancer in Norfolk (EPIC-Norfolk) Eye Study. Methods: Glaucoma detection with variable corneal compensation (GDx-VCC) and Heidelberg Retinal Tomograph II (HRT II) derived global mean RNFL thickness from dementia-free participants at baseline within the EPIC-Norfolk Eye Study were analyzed. Incident dementia was identified through linkage to electronic medical records. Cox proportional hazard mixed-effects regression models adjusted for key confounders were used to examine the associations between RNFL thickness and incident dementia in four separate models. Results: 6,239 participants were included with 322 cases of incident dementia and mean age of 67.5-years old, with 49.7% women (median follow-up 13.2-years, interquartile range (11.7 to 14.6 years). Greater RNFL thickness (GDx-VCC) was not significantly associated with a lower risk of incident dementia in the full adjusted model [HR per quartile increase 0.95; 95% CI 0.82–1.10]. Similarly, RNFL thickness assessed with HRT II was also not associated with incident dementia in any model (full adjusted model; HR per quartile increase: 1.06; [95% CI 0.93–1.19]. Gender did not modify any associations under study. Conclusion: GDx-VCC and HRT II derived RNFL thickness are unlikely to be useful predictors of incident dementia. Higher resolution optical imaging technologies may clarify whether there are useful relationships between neuro-retinal morphology and brain measures. [ABSTRACT FROM AUTHOR]

This study tested whether repeated traumatic brain injuries (TBIs) alter the objective structure or the objective function of retinal ganglion cells (RGCs) in human subjects recruited from an optometry clinic. Case subjects (n = 25) with a history of repeated TBIs (4.12 ± 2.76 TBIs over 0-41 years) and healthy pair-matched control subjects (n = 30) were prospectively recruited. Retinal nerve fiber layer (RNFL) thickness was quantified with spectral-domain optical coherence tomography, and scanning laser polarimetry measured RNFL phase retardation. Measurements of the photopic negative response were made using full-field flash electroretinography. There was no statistically significant difference (p = 0.42) in global RNFL thickness between the case cohort (96.6 ± 9.4microns) and the control cohort (94.9 ± 7.0microns). There was no statistically significant difference (p = 0.80) in global RNFL phase retardation between the case cohort (57.9 ± 5.7 nm) and the control cohort (58.2 ± 4.6 nm). There were no statistically significant differences in the peak time (p = 0.95) of the PhNR or in the amplitude (p = 0.11) of the PhNR between the case cohort (69.9 ± 6.9ms and 24.1 ± 5.1 µV, respectively) and the control cohort (70.1 ± 8.9ms and 27.8 ± 9.1 µV, respectively). However, PhNR amplitude was more variable (p < 0.025) in the control cohort than in the case cohort. Within the case cohort, there was a strong positive (r = 0.53), but not statistically significant (p = 0.02), association between time since last TBI and PhNR amplitude. There was also a modest positive (r = 0.45), but not statistically significant (p = 0.04), association between time since first TBI and PhNR amplitude. Our results suggest that there were no statistically significant differences in the objective structure or in the objective function of RGCs between the case cohort and the control cohort. Future large, longitudinal studies will be necessary to confirm our negative results and to more fully investigate the potential interaction between PhNR amplitude and time since first or last TBI. [ABSTRACT FROM AUTHOR]

Hypertension is a major cardiovascular risk factor that is responsible for a heavy burden of morbidity and mortality worldwide. A critical aspect of cardiovascular risk estimation in hypertensive patients depends on the assessment of hypertension-mediated organ damage (HMOD), namely the generalized structural and functional changes in major organs induced by persistently elevated blood pressure values. The vasculature of the eye shares several common structural, functional, and embryological features with that of the heart, brain, and kidney. Since retinal microcirculation offers the unique advantage of being directly accessible to non-invasive and relatively simple investigation tools, there has been considerable interest in the development and modernization of techniques that allow the assessment of the retinal vessels' structural and functional features in health and disease. With the advent of artificial intelligence and the application of sophisticated physics technologies to human sciences, consistent steps forward have been made in the study of the ocular fundus as a privileged site for diagnostic and prognostic assessment of diverse disease conditions. In this narrative review, we will recapitulate the main ocular imaging techniques that are currently relevant from a clinical and/or research standpoint, with reference to their pathophysiological basis and their possible diagnostic and prognostic relevance. A possible non pharmacological approach to prevent the onset and progression of retinopathy in the presence of hypertension and related cardiovascular risk factors and diseases will also be discussed. [ABSTRACT FROM AUTHOR]

This study quantified and compared phase retardation distribution in the central macula with the thickness of the Henle fiber layer (HFL). A scanning laser polarimeter (SLP) was used to acquire 20° × 40° macular-centered images, either with fixed corneal compensation or with variable corneal compensation, in two cohorts of clinically normal subjects (N = 36). Phase retardation maps from SLP imaging were used to generate a macular cross pattern (fixed compensation) or an annulus pattern (variable compensation) centered on the macula. Intensity profiles in the phase retardation maps were produced using annular regions of interest at eccentricities from 0.25° to 3°. Pixel intensity was averaged at each eccentricity, acting as a surrogate for macular phase retardation. Directional OCT images were acquired in the horizontal and vertical meridians in all subjects, allowing visualization of the HFL thickness. HFL thickness was manually segmented in each meridian and averaged. In both cohorts, phase retardation and HFL thickness were highly correlated in the central 3° assessed, providing further evidence that the source of the phase retardation signal in the central macula is dominated by the HFL and that the center of the macula on cross sectional imaging corresponds closely with the center of the macular cross on SLP imaging.

Purpose: A central diagnostic tool in adult glaucoma is the peripapillary retinal nerve fibre layer (pRNFL) thickness. It can be assessed by scanning laser polarimetry (SLP) or optical coherence tomography (OCT). However, studies investigating the relevance of pRNFL measurements in children are rare. This study aims to compare the glaucoma diagnosing ability of SLP and OCT pRNFL thickness measurements in a paediatric population. Methods: This retrospective study included 105 children (glaucoma: 22 (21.0%); healthy glaucoma suspects: 83 (79.0%)) aged 4–18 years, examined with SLP (GDxPro/ECC, Carl Zeiss Meditec) and spectral-domain OCT (SPECTRALIS®, Heidelberg Engineering). The thickness of pRNFL sectors was compared between diseased and healthy participants. Areas under the receiver-operating characteristic curves (AUC) and logistic regression results were used to compare the glaucoma discriminative capacity between SLP and OCT measurements. Results: Using OCT, pRNFL thickness was decreased in the superior, nasal, and inferior quadrants of glaucoma patients compared to healthy controls (P < 0.001, each). With SLP, such a difference was only observed in the inferior quadrant (P = 0.011). A correlation between glaucoma diagnosis and OCT-measured pRNFL thickness was found in all quadrants (P < 0.001) other than the temporal. With SLP, a correlation was found for the total average thickness (P = 0.037) and inferior quadrant (P = 0.0019). Finally, the AUCs of OCT measurements were markedly higher than those of SLP (e.g., inferior quadrant: OCT 0.83, SLP 0.68). Conclusion: pRNFL thickness measurements using both OCT and SLP, correlate notably with the presence of glaucoma. In general, the diagnostic performance of pRNFL thickness measurements seems higher for OCT than for SLP. Thus, pRNFL thickness measurements could provide important information, complementing conventional clinical and functional parameters in the diagnostic process of paediatric glaucoma. [ABSTRACT FROM AUTHOR]

Copyright of Arquivos Brasileiros de Oftalmologia is the property of Arquivos Brasileiros de Oftalmologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: Goldmann applanation tonometer (GAT) is the current Gold standard tonometer. However, its calibration error is common and can go unnoticed in clinics. Its company repair has limitations. The purpose of this report is to describe a self-taught technique of rectifying calibration error of GAT. Materials and Methods: Twenty-nine slit-lamp-mounted Haag-Streit Goldmann tonometers (Model AT 900 C/M; Haag-Streit, Switzerland) were included in this cross-sectional interventional pilot study. The technique of rectification of calibration error of the tonometer involved cleaning and lubrication of the instrument followed by alignment of weights when lubrication alone didn′t suffice. We followed the South East Asia Glaucoma Interest Group′s definition of calibration error tolerance (acceptable GAT calibration error within ±2, ±3 and ±4 mm Hg at the 0, 20 and 60-mm Hg testing levels, respectively). Results: Twelve out of 29 (41.3%) GATs were out of calibration. The range of positive and negative calibration error at the clinically most important 20-mm Hg testing level was 0.5 to 20 mm Hg and -0.5 to -18 mm Hg, respectively. Cleaning and lubrication alone sufficed to rectify calibration error of 11 (91.6%) faulty instruments. Only one (8.3%) faulty GAT required alignment of the counter-weight. Conclusions: Rectification of calibration error of GAT is possible in-house. Cleaning and lubrication of GAT can be carried out even by eye care professionals and may suffice to rectify calibration error in the majority of faulty instruments. Such an exercise may drastically reduce the downtime of the Gold standard tonometer.

Purpose: The aim was to study choroidal thickness (CT) and its profile based on location in healthy Indian subjects using Cirrus high definition (HD) optical coherence tomography. Materials and Methods: A total of 211 eyes of 115 healthy subjects with no retinal or choroidal disease were consecutively scanned using Cirrus HD 1 line raster scan mode without pupillary dilation. Eyes with any ocular disease or axial length (AXL) >24 mm or

Aim: The aim was to ascertain if any differences exist in diurnal central corneal thickness (CCT) and intra-ocular pressure (IOP) between eyes with pseudoexfoliation (PXF) syndrome without glaucoma and eyes with no ocular pathology. A secondary aim was to determine whether there was a significant relationship between CCT and IOP. Settings and Design: This study was a prospective design conducted within a hospital setting. Materials and Methods: The experimental group consisted of seven participants with bilateral PXF (14 eyes) and the control group comprised of 15 participants (30 eyes). Testing included CCT and IOP measured at four different times on one given day (8.00 a.m.; 11 a.m.; 2 p.m. and 5 p.m.). Statistical Analysis: The data were analyzed with the generalized linear latent mixed model. Results: PXF eyes displayed a significantly thinner overall mean CCT (520 μm) compared to controls (530 μm). Furthermore, a significant reduction in CCT and IOP occurred in the PXF group from 8 a.m. to 5 p.m. The mean overall IOP in PXF eyes was significantly lower than the control group. A significant association between IOP and CCT was also found in PXF eyes. Conclusions: Displaying a significantly thinner mean CCT highlights the importance of measuring CCT in an ophthalmic clinical setting as to avoid falsely underestimated IOP measurements in such a high-risk glaucoma population. Furthermore, a statistically significant correlation between IOP and CCT in PXF eyes suggests that the reduction in CCT that occurred in PXF eyes between 8 a.m. and 5 p.m. may be partly responsible for the reduction in IOP measurements.

Purpose: The purpose was to evaluate the results of bilateral lateral rectus (BLR) recession which is based on augmented surgical amounts of classical surgical table of Parks′ for basic and pseudo-divergence excess type intermittent exotropia [X(T)]. Materials and Methods: Patients with X(T) operated by the same surgeon and followed-up for at least 6 months were included. Patients with prior surgery, neurobehavioral and musculoskeletal conditions, strabismus different from that mentioned above X(T) were excluded. All the patients received BLR only. The amount of the recession was increased by the amount needed to correct 5 prism diopters (PD) more X(T) than what was measured. After the operation, 1 st week, 2 nd and 6 months measurements were recorded. The patients were grouped according to their 1 st week (3-7 days) postoperative examination as: >10 PD esotropia (Group 1), ≤10 PD esotropia (Group 2), exotropia (Group 3), and orthotropic (Group 4), respectively. Final surgical outcomes were classified as "good" (≤10 PD exotropia and ≤5 PD esotropia), "recurrence" (>10 PD exotropia) and "overcorrected" (>5 esotropia). Results: Thirty-seven patients were included. The mean age was 6.78 ± 2.87 years (range: 2-12 years). Mean preoperative deviation was 29.72 ± 8.07 PD (range: 15-45 PD) at distance and 20.94 ± 11.65 PD (range: 10-45 PD) at near (P < 0.0001). There were 21 (56.8%) patients in Group 1, 9 (24.3%) patients in Group 2, 1 (2.7%) patient in Group 3 and 6 (16.2%) patients in Group 4. Initial esotropia was achieved in 30 (30/37) of the patients. Twenty-eight of them had good results at the end of the 6 months. Overall "motor surgical" success rate was found to be 89.2% (33/37 patients), with 1 (2.7%) overcorrection and 3 (8.1%) recurrences at the end of the 6 months. Conclusion: This study demonstrated that early overcorrection of 10-20 PD after X(T) surgery can achieve acceptable motor outcomes in the first 6 months postoperative period.

Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmologνa Mιdica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a Student′s t-test. Results: Orange lens filtered more of the blue spectrum (cut-off wavelength of 370 nm) than the yellow lens (390 nm). The MTF of the yellow lens was better than the orange lens (average modulation of 0.676 for natural and 0.672 for orange). The patients′ BCVA was 0.02 + 0.10 logMAR for both lenses. The CSF obtained with the yellow lens was slightly better, although without statistically significant differences (P > 0.05). Conclusions: Both lenses are of good optical quality. The patients′ visual quality was similar with both lenses, and optical quality was also similar. The color of the lens does not affect the visual quality of the patient.

Objective: The objective was to provide evidence-based care for patients with traumatic cataracts, we assessed whether a posterior capsulotomy and anterior vitrectomy, as part of the primary surgical procedure, could be a positive predictor of final visual outcome. Materials and Methods: This is a prospective randomized control trial. Patients presenting at our hospital between January 2010 and December 2012 having ocular trauma and traumatic cataracts were enrolled, according to the inclusion criteria. We enrolled two groups: Those with and without primary posterior capsulotomy and vitrectomy. Information regarding demographic and ocular trauma were collected using the World Eye Trauma Registry form at the first visit and follow-up, and specific information was collected for both the group who underwent posterior capsulectomies and vitrectomies as a part of the primary procedure, and the control group. Data were analyzed to evaluate the predictive value of primary posterior capsulectomy and anterior vitrectomy. Results: We enrolled 120 cases, 60 in each group, comprising 31 females and 89 males. When all other variables were controlled for, the visual outcome (best corrected visual acuity) differed significantly (P < 0.001) between the groups. Conclusion: Performance of posterior capsulectomy and anterior vitrectomy as part of the primary procedure improves the final visual outcome.

Publishing manuscripts is the only way by which scientists communicate with each other. In recent times, there is an increasing desire to publish manuscripts from the developing world for a variety of reasons. Though, performing a research study is challenging in itself, writing it for publication is the final frontier that can be daunting, especially for the novice. Work that remains unpublished in one form or the other is essentially incomplete or undone. Hence, it is critically important for one to publish one′s findings in a reputed journal. The purpose of this paper is to alleviate the mystique involved in manuscript writing and provide a blueprint where the subheadings given under each of the sections of introduction, methods, results and discussion can be expanded as per the particular study and the manuscript can be constructed in a stepwise manner. We hope that by following this approach, potential researchers and practicing ophthalmologists will develop the skill and aptitude for medical writing, and that the developing world shall do justice to its tremendous intellectual capital by making meaningful contributions to global scientific literature.

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far.

The purpose of the review is to provide an update on the role of imaging devices in the diagnosis and follow-up of glaucoma with an emphasis on techniques for detecting glaucomatous progression and the newer spectral domain optical coherence tomography instruments. Imaging instruments provide objective quantitative measures of the optic disc and the retinal nerve fiber layer and are increasingly utilized in clinical practice. This review will summarize the recent enhancements in confocal scanning laser ophthalmoscopy, scanning laser polarimetry, and optical coherence tomography with an emphasis on how to utilize these techniques to manage glaucoma patients and highlight the strengths and limitations of each technology. In addition, this review will briefly describe the sophisticated data analysis strategies that are now available to detect glaucomatous change overtime.

Introduction: Histopathological features in retinoblastoma are considered high-risk factors (HRF) for tumor progression and metastasis, thus their presence becomes an indication for adjuvant chemotherapy. Present study was undertaken to evaluate the incidence of HRF in retinoblastoma and to correlate them with p53 expression. Materials and Methods: This was a retrospective study where 17 diagnosed cases of retinoblastoma were included. Cases were re-evaluated for various histomorphological parameters. Immuno-histochemical analysis was done with p53 antibody by Streptavidin biotin method. Results: The patients were in the age range of 1.5-50 years. Common histological features included necrosis (70.5%), calcification (64.7%), and retinal detachment (58.8%). Incidence of various morphological parameters was anterior chamber seeding (47.2%), ciliary body involvement (29.4%), iris involvement (29.4%), choroid involvement (58.8%), scleral invasion (29.4%), extrascleral invasion (11.8%), and optic nerve infiltration (23.5%). p53 expression was present in four cases out of 13 cases (30.7%) and showed a significant association with choroid invasion (P = 0.02). Discussion: The presence of HRF should alert the physician for a possible metastasis, and such patients should be kept on regular follow-up to detect an early recurrence. p53 expression, a known poor prognostic indicator, showed significant association with choroid invasion, however, no association was seen with other HRF. Conclusion: Histopathological HRF have significant therapeutic and prognostic implications. The incidence of HRF is higher in developing countries as patients present with a more advanced stage of disease. p53 expression is significantly associated with choroid invasion out of all HRF.

We report a case of a 2-month-old baby with bilateral nonsyndromic partial cryptophthalmos presenting with upper eyelid incomplete development and fusion to the cornea with resultant inability to close the eyes. He was managed successfully with bilateral upper lid reconstruction with composite graft using maternal skin and oral mucous membrane, amniotic membrane, and donor scleral graft. After this one stage surgery, lids were well-formed, and the patient was able to close both eyes, thus achieving good anatomical, functional, and cosmetic outcome.

Intravitreal application of Ozurdex ® (Allergan, Inc., Irvine, CA, USA) which is a biodegradable, sustained-release dexamethasone implant has been reported to be effective in the treatment of macular edema. Migration of such implant into the anterior chamber has been recently described in cases without perfect zonular or the posterior capsular integrity. Herein, we report the first case with anterior migration of Ozurdex ® implant that mislocated just behind the intraocular lens (IOL) in an intact capsular bag. It is thought that such implant migrated anteriorly towards into the posterior chamber through weak zonules as the present case had a medical history of uneventful phacoemulsification surgery with the implantation of posterior chamber IOL. However, the migrated implant was well tolerated since there was no sign of the corneal complication, rise in intraocular pressure, and anterior chamber reaction. Close follow-up was scheduled to find out any signs of anterior segment pathology. Meanwhile dexamethasone implant completely degraded at the 4 th month of postoperative follow-up.

Purpose: To evaluate the correlation between automated achromatic perimetry (AAP) and the output of two retinal nerve fiber layer (RNFL) analysers: scanning laser polarimetry (GDx-VCC) and optical coherence tomography (OCT). Methods: Quantitative RNFL measurements with GDx-VCC and Stratus-OCT were obtained in one eye from 52 healthy subjects, 38 ocular hypertensive (OHT) patients and 94 glaucomatous patients. All patients underwent a complete examination, including AAP using the Swedish interactive threshold algorithm (SITA). The relationship between RNFL measurements and SITA visual field global indices were assessed by means of the following methods: analysis of variance, bivariate Pearson's correlation coefficient, multivariate linear regression techniques and nonlinear regression models, and the coefficient of determination (r2) was calculated. Results: RNFL thickness values were significantly lower in glaucomatous eyes than in healthy and ocular hypertensive eyes for both nerve fiber analysers (P≤0.001), except for the inferior 120° average thickness in GDx-VCC. Linear regression models constructed for GDx-VCC measurements and OCT-derived RNFL thickness with SITA visual field global indices demonstrated that, for the mean deviation, the only predictor in the model was the nerve fiber indicator for GDx-VCC (r2=0.255), and for the pattern standard deviation, the predictors in the model were the nerve fiber indicator for GDx-VCC (r2=0.246) and the maximum thickness in the superior quadrant for Stratus-OCT (r2=0.196). The best curvilinear fit was obtained with the cubic model. Conclusions: Quantitative measurements of RNFL thickness using either GDx-VCC or OCT correlate moderately with visual field global indices in moderate glaucoma patients. We did not find a correlation between visual field global indices and RNFL thickness in early glaucoma patients. Further study is needed to develop new analytical methods that will increase RNFL analyser's sensitivity in early glaucoma patients.

Background: The effect of obstructive sleep apnea (OSA) syndrome in the peripapillary retinal nerve fiber layer (RNFL) thicknesses remains unclear. The purpose of this study was to assess RNFL measurements acquired using scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in patients with OSA.Methods: The sample of this cross-sectional study included 40 OSA patients and 45 age-matched controls, consecutively and prospectively selected. All participants underwent at least one reliable standard automated perimetry (SAP) test, while RNFL measurements were obtained using the SLP and OCT. The OSA group was divided into 3 sub-groups based on the apnea/hypopnea index (AHI): mild, moderate, or severe OSA. SAP, SLP, and OCT outcomes were compared between the control and OSA groups. The relationship between AHI and RNFL parameters was also evaluated.Results: Age was not different between both groups. Mean deviation of SAP was -0.47 ± 0.9 dB and -1.43 ± 2.3 dB in the control and OSA groups, respectively (p = 0.01). RNFL thickness measured with OCT was similar between groups. OSA patients showed increased nerve fiber indicator (NFI; 20.9 ± 7.9 versus 16.42 ± 7.82; p = 0.01) and decreased superior average (59.74 ± 10.35 versus 63.73 ± 6.58; p = 0.03) obtained with SLP compared with healthy individuals. In the total sample, NFI and AHI were moderately correlated (r = 0.358; p = 0.001). In severe OSA subjects (n = 22), NFI and AHI had a Spearman correlation coefficient of 0.44 (p = 0.04).Conclusion: RNFL thickness measured with OCT did not differ significantly between groups. Severe OSA was related to a reduction of the RNFL thickness assessed by SLP. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate photopic negative response (PhNR) discrimination ability between healthy and glaucomatous patients. Methods: Ninety eyes of 50 patients with primary open angle glaucoma (POAG) and 45 eyes of 23 healthy age- and sex-matched controls were investigated. Based on European Glaucoma Society criteria, POAG patients were divided into three groups: early, moderate and advanced glaucoma. Following measurements were analysed: mean defect (MD) from Humphrey Visual Field Analyzer, SITA standard 24-2 white on white perimetry; nerve fibre index (NFI) obtained from scanning laser polarimetry; and GDx and PhNR amplitude and PhNR/b-wave ratio. PhNR was elicited by red stimuli with flash strength of 1.6 cd s/m on blue background of 25 cd/m. Correlations between retinal ganglion cells function (PhNR), retinal sensitivity (MD) and structure (NFI) were calculated. Sensitivity and specificity of PhNR parameters were calculated with standard formulas. Receiver operating characteristic (ROC) curves were used to determine optimal cut-off values. The area under the curve (AUC) was used to compare the ROC curves results between PhNR amplitude and ratio. Results: PhNR amplitude and ratio were significantly reduced in early, moderate and advanced glaucoma groups compared to controls. The sensitivity and specificity to detect glaucoma in early POAG were equal to 53.3 and 90.0 % for PhNR amplitude and 60.0 and 70.0 % for PhNR ratio; in moderate POAG 63.3 and 80.0 % for PhNR amplitude and 60.0 and 86.7 % for PhNR ratio; and in advanced POAG 76.6 and 80.0 % for PhNR amplitude, 90.0 and 73.3 % for PhNR ratio. There were no significant differences between AUC for PhNR amplitude (0.76-0.86) and PhNR ratio (0.78-0.86), p > 0.05. PhNR amplitudes and ratios correlated significantly with MD measured by SAP and NFI obtained from GDx ( p < 0.05). PhNR amplitude significantly decreases with advancement of visual field defects in glaucoma patients. Conclusions: PhNR reveals dysfunction of RGCs in early, moderate and advanced stage of POAG. PhNR has good discrimination ability in detecting glaucomatous patients. PhNR might be a useful test in glaucoma diagnosis. [ABSTRACT FROM AUTHOR]

Purpose: Whether retinal degeneration is part of the degenerative processes in patients with Parkinson's disease (PD) is still unclear. This cross-sectional study was undertaken to compare the retinal morphology of patients with PD and healthy controls using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP). Methods: Both eyes of patients with PD (n = 108) and healthy controls (n = 165) were examined using SD-OCT and SLP on the same day. Data on the thickness of the retinal nerve fibre layer (RNFL) of all quadrants and the macular area were acquired by OCT (Cirrus, Zeiss). The SLP device (Glaucoma diagnostics (GDx), Zeiss) measured the RNFL and calculated the nerve fibre index (NFI). All patients and probands were checked for concomitant ocular disorders by an ophthalmologist. Visual acuity, intraocular pressure (IOP), objective refraction and the anterior and posterior segment were assessed. Results: Patients with PD showed a reduced macular volume and a reduced central subfield thickness in OCT examinations. The RNFL in the different quadrants did not differ significantly from that of controls. SLP data showed a reduced average RNFL thickness, a decreased thickness of the inferior quadrant and an increase of the NFI in patients with PD. Conclusion: PD may be associated with reduced thickness and volume of the macula and a reduced thickness of the RNFL in the inferior quadrant of the retina. Investigations using SD-OCT and SLP revealed distinct but significant differences between patients with PD and healthy controls. [ABSTRACT FROM AUTHOR]

The goal of this review is to summarize the most common imaging methods currently applied for in vivo assessment of ocular structure in animal models of experimental glaucoma with an emphasis on translational relevance to clinical studies of the human disease. The most common techniques in current use include optical coherence tomography and scanning laser ophthalmoscopy. In reviewing the application of these and other imaging modalities to study glaucomatous optic neuropathy, this article is organized into three major sections: 1) imaging the optic nerve head, 2) imaging the retinal nerve fiber layer and 3) imaging retinal ganglion cell soma and dendrites. The article concludes with a brief section on possible future directions. [ABSTRACT FROM AUTHOR]

Purpose To evaluate the effect of typical scan score ( TSS), when within the acceptable limits, on the diagnostic performance of retinal nerve fibre layer ( RNFL) parameters with the enhanced corneal compensation ( ECC) protocol of scanning laser polarimetry ( SLP) in glaucoma. Methods In a cross-sectional study, 203 eyes of 160 glaucoma patients and 140 eyes of 104 control subjects underwent RNFL imaging with the ECC protocol of SLP. TSS was used to quantify atypical birefringence pattern ( ABP) images. Influence of TSS on the diagnostic ability of SLP parameters was evaluated by receiver operating characteristic ( ROC) regression models after adjusting for the effect of disease severity [based on mean deviation ( MD)] on standard automated perimetry). Results Diagnostic abilities of all RNFL parameters of SLP increased when the TSS values were higher. This effect was statistically significant for TSNIT (coefficient: 0.08, p < 0.001) and inferior average parameters (coefficient: 0.06, p = 0.002) but not for nerve fibre indicator ( NFI, coefficient: 0.03, p = 0.21). In early glaucoma ( MD of −5 dB), predicted area under ROC curve ( AUC) for TSNIT average parameter improved from 0.642 at a TSS of 90 to 0.845 at a TSS of 100. In advanced glaucoma ( MD of −15 dB), AUC for TSNIT average improved from 0.832 at a TSS of 90 to 0.947 at 100. Conclusion Diagnostic performances of TSNIT and inferior average RNFL parameters with ECC protocol of SLP were significantly influenced by TSS even when the TSS values were within the acceptable limits. Diagnostic ability of NFI was unaffected by TSS values. [ABSTRACT FROM AUTHOR]

Glaucoma is an acquired progressive optic neuropathy which is characterized by changes in the optic nerve head and retinal nerve fiber layer (RNFL). White-on-white perimetry is the gold standard for the diagnosis of glaucoma. However, it can detect defects in the visual field only after the loss of as many as 40% of the ganglion cells. Hence, the measurement of RNFL thickness has come up. Optical coherence tomography and scanning laser polarimetry (SLP) are the techniques that utilize the evaluation of RNFL for the evaluation of glaucoma. SLP provides RNFL thickness measurements based upon the birefringence of the retinal ganglion cell axons. We have reviewed the published literature on the use of SLP in glaucoma. This review elucidates the technological principles, recent developments and the role of SLP in the diagnosis and monitoring of glaucomatous optic neuropathy, in the light of scientific evidence so far. [ABSTRACT FROM AUTHOR]

This review article is meant to help biomedical engineers and nonphysical scientists better understand the principles of, and the main trends in modern scanning and imaging modalities used in ophthalmology. It is intended to ease the communication between physicists, medical doctors and engineers, and hopefully encourage "classical" biomedical engineers to generate new ideas and to initiate projects in an area which has traditionally been dominated by optical physics. Most of the methods involved are applicable to other areas of biomedical optics and optoelectronics, such as microscopic imaging, spectroscopy, spectral imaging, opto-acoustic tomography, fluorescence imaging etc., all of which are with potential biomedical application. Although all described methods are novel and important, the emphasis of this review has been placed on three technologies introduced in the 1990's and still undergoing vigorous development: Confocal Scanning Laser Ophthalmoscopy, Optical Coherence Tomography, and polarization-sensitive retinal scanning. [ABSTRACT FROM AUTHOR]

The prevalence and nature of corneal astigmatism among patients with cataract has not been well-documented in the resident African population. This retrospective study was undertaken to investigate preexisting corneal astigmatism in adult patients with cataract. We analyzed keratometric readings acquired by manual Javal-Schiotz keratometry before surgery between January 1, 2011 and December 31, 2011. There were 3,169 patients (3286 eyes) aged between 16 and 110 years involved with a Male to female ratio of 1.4:1. Mean keratometry in diopters was K1 = 43.99 and K2 = 43.80. Mean corneal astigmatism was 1.16 diopter and a majority (45.92%) of eyes had astigmatism between 1.00 and 1.99 diopters. Two-thirds of the eyes (66.9%) in this study had preoperative corneal astigmatism equal to or above 1.00 diopter. Findings will help local cataract surgeons to estimate the potential demand for toric intraocular lenses.

The aim of this work was to investigate the correlation between scanning laser polarimetry with variable corneal compensation (GDx VCC) parameters and blue-on-yellow perimetry (B/YP) indices in ocular hypertension (OHT). One eye each of 52 patients with OHT (with a normal visual field, a normal optic nerve, and an untreated IOP > 21 mmHg) was chosen. All patients were examined with the Octopus 101 automated perimetry dG2 program using the dynamic/normal strategy (white-on-white perimetry, W/WP), with the dG2 program using the dynamic strategy/BY method (blue-on-yellow perimetry, B/YP), and with GDx VCC. Seven of the 52 OHT patients had both B/YP visual field loss and retinal nerve fiber layer (RNFL) defects with the GDx VCC measurements, and four patients demonstrated regions of B/YP visual field defects with corresponding RNFL defects on GDx VCC examination. A mild significant correlation was found between B/YP mean sensitivity (MS) and the superior average ( R =0.138, p = 0.049). No significant correlation was found between the W/WP indices and GDx VCC parameters. B/YP MS correlated with the superior average of GDx VCC in OHT patients. The findings brought up the possibility of using both techniques for clinical examination to yield converging data. [ABSTRACT FROM AUTHOR]

. Purpose: To compare the thickness of the retinal nerve fibre layer (RNFL) in hydrophthalmic glaucomatous eyes in children with age-matched healthy controls using scanning laser polarimetry with variable corneal compensation (GDxVCC). Methods: Twenty hydrophthalmic eyes of 20 patients with the mean age of 10.64 ± 3.02 years being treated for congenital or infantile glaucoma were included in the analysis. Evaluation of RNFL thickness measured by GDxVCC in standard Temporal-Superior-Nasal-Inferior-Temporal (TSNIT) parameters was performed. The results were compared to TSNIT values of an age-matched control group of 120 healthy children published recently as referential values. The correlation between horizontal corneal diameter and RNFL thickness in hydrophthalmic eyes was also investigated. Results: The mean ± SD values in TSNIT Average, Superior Average, Inferior Average and TSNIT SD in hydrophthalmic eyes were 52.3 ± 11.4, 59.7 ± 17.1, 62.0 ± 15.6 and 20.0 ± 7.8 μm, respectively. All these values were significantly lower compared to referential TSNIT parameters of age-matched healthy eyes (p = 0.021, p = 0.001, p = 0.003 and p = 0.018, respectively). A substantial number of hydrophthalmic eyes laid below the level of 5% probability of normality in respective TSNIT parameters: 30% of the eyes in TSNIT average, 50% of the eyes in superior average, 30% of the eyes in inferior average and 45% of the eyes in TSNIT SD. No significant correlation between enlarged corneal diameter and RNFL thickness was found. Conclusions: The mean values of all standard TSNIT parameters assessed using GDxVCC in hydrophthalmic glaucomatous eyes in children were significantly lower in comparison with referential values of healthy age-matched children. [ABSTRACT FROM AUTHOR]

Background: Scanning laser polarimetry (SLP) is a method that enables quantitative assessment of retinal nerve fibre layer (RNFL) thickness surrounding the optic nerve. The commercially available device GDx (GDx, Laser Diagnostics Technologies, San Diego, CA) yields an outprint consisting of a reflectance image, colour-coded retardation map, and the 14 parameters, of which the »Number« was shown to be the single best parameter to discriminate between glaucomatous and normal eyes. The »Number« is a probability score, ranging from 1 (low probability of glaucoma) to 100 (high probability of glaucoma). In our study we determined the sensitivity and the specificity of the »Number« at cutoff values of 23 and 30. Methods: Thirty patients with different stage of glaucoma and 14 patients with typical glaucomatous changes of the ONH without visual field loss (preperimetric glaucoma) were included in the analysis. The control group was represented by 27 adults without ocular pathology with intraocular pressure of < 21 mmHg and normal visual fields. The sensitivity and specificity of the »Number« was determined at a cut-off level of 23 and 30. Results: The sensitivity of the »Number« at a cut-off level of 30 for the glaucoma group was 74% at a specificity of 86%, at a cut-off of 23 the sensitivity increased to 83% at a specificity of 76%. The discriminating ability of the »Number« in the group with preperimetric glaucoma was low, with the sensitivities of 36% and 50% at a cut-off value of 30 and 23, respectively.Conclusions: The parameter »Number« yielded good separation between normal eyes and eyes with moderate and advanced glaucoma. However, the sensitivity of the »Number« in eyes with mild glaucoma and especially with preperimetric glaucoma was low. Because of the great interindividual variability of the RNFL, the assessment of RNFL thickness change over time would be more appropriate to detect early glaucomatous changes.

Abstract: Objective: Retinal nerve fiber layer (RNFL) loss occurs with MS or after optic neuritis. Acute RNFL alterations at presentation and changes over time have not been well documented. We analyzed regional RNFL changes using 2 methods, ocular coherence tomography (OCT) and scanning laser polarimetry (SLP), to study initial edema and early RNFL loss. Methods: 40 subjects with unilateral acute optic neuritis, had prospective OCT and SLP RNFL thickness values organized into 4 quadrants. We compared affected with normal fellow and control eyes to determine RNFL thickening (≥10% of 95th percentile of controls) and thinning (≥10μ less than fellow eye) at presentation, 1 and 3months. Results: RNFL thickening occurred in 27/33 eyes (82%) by OCT and in 21/34 eyes (62%) by SLP at baseline. At 1month, RNFL thickening was common even as thinning developed in 15/23 (65%) of eyes by OCT and in 15/28 eyes (54%) by SLP. At 3months, RNL was thinned by OCT in 14/24 (58%) and by SLP in 15/25 (60%) affected eyes (58%). Neither MRI optic nerve lesion nor vision at baseline correlated with optical image findings or vision outcome. Conclusions: RNFL swelling, most likely due to axoplasmic stasis from blockade at the lesion site in optic neuritis, is seen with OCT better than SLP. RNFL swelling in some quadrants and loss in others occur at 1month and is well seen with interocular comparison by both methods. Optical imaging provides pathophysiologic as well as quantitative information regarding axonal changes. [Copyright &y& Elsevier]

The aim of the study was to evaluate the effect of human immunodeficiency virus infection on the retinal nerve fibre layer. The thickness was assessed in 48 human immunodeficiency virus--positive patients using scanning laser polarimetry. Results were compared to normal values and tested against factors suspected to affect the retinal nerve fibre layer. The mean value of the thickness was 57.65 ±± 6.18 µµm in our cohort. No significant correlation between the retinal nerve fibre layer thickness and the immune profile or antiretroviral therapy was detected. However, a significant negative correlation between the retinal nerve fibre layer thickness with increasing length of human immunodeficiency virus infection was found. [ABSTRACT FROM AUTHOR]

PurposeTo review the ability of current imaging technologies to provide estimates of rates of structural change in glaucoma patients.Patients and methodsReview of literature.ResultsImaging technologies, such as confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT), provide quantifiable and reproducible measurements of the optic disc and parapapillary retinal nerve fibre layer (RNFL). Rates of change as quantified by the rim area (RA) (for CSLO) and RNFL thickness (for SLP and OCT) are related to glaucoma progression as detected by conventional methods (eg, visual fields and optic disc photography). Evidence shows that rates of RNFL and RA loss are significantly faster in progressing compared with non-progressing glaucoma patients.ConclusionMeasurements of rates of optic disc and RNFL change are becoming increasingly precise and individualized. Currently available imaging technologies have the ability to detect and quantify progression in glaucoma, and their measurements may be suitable end points in glaucoma clinical trials. [ABSTRACT FROM AUTHOR]

Background: Since papilledema in idiopathic intracranial hypertension is a passive event not primarily affecting the visual tract, resolution with restitution ad integrum is expected if intracranial pressure is rebalanced. Retinal nerve fiber swelling due to papilledema in the acute phase and possible axon loss after long-lasting elevated intracranial pressure was investigated in a controlled cross-sectional study by scanning laser polarimetry. Methods: A cohort of 23 patients with idiopathic intracranial hypertension according to the modified Dandy diagnostic criteria, and 23 controls matched for age and gender were investigated. All patients received neurological and ophthalmologic examination including scanning laser polarimetry (GDx VCC). Patients were divided into groups depending on the presence of a papilledema (group 1) or the regression of the papilledema after initiation of therapy (group 2). Therapy was based on recommendations of the German Society of Neurology. Results: Scanning laser polarimetry showed an increase of nerve fiber thickness in group 1, and a decrease of the nerve fiber thickness in group 2 compared to controls. Ten of 13 patients showed signs of a regional axon loss in the deviation map of the GDx report, and six had a Nerve Fiber Index above 30. All patients with regressive papilledema and coincidence of visual field damage and pale optic disc appearance had a pathologic result in the GDx examination, but only four of ten patients with a pathologic GDx examination showed coincidence of pale optic disc appearance and visual field damage as sign of underlying optic disc atrophy. Conclusion: In patients with apparently effective treatment of clinical symptoms and a regression of papilledema in idiopathic intracranial hypertension, a retinal axon loss was detected by scanning laser polarimetry. Axon loss was even present in patients without clinical evidence of optic nerve atrophy. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate glaucoma diagnostic capability of the retinal nerve fiber layer (RNFL) imaging by spectral-domain optical coherence tomography (Cirrus OCT) and scanning laser polarimetry (GDx VCC). Methods: We imaged 88 glaucomatous and 77 healthy eyes using both devices. Areas under the receiver-operating characteristic curves (area under the curves, AUCs) and sensitivities at fixed specificities of average, superior, and inferior RNFL thickness were compared. Likelihood ratios (LRs) and diagnostic agreement based on normative classifications yielded by both devices were determined. Results: The best performing parameter was the nerve fiber indicator (NFI) in GDx VCC and inferior RNFL thickness in Cirrus OCT (AUC = 0.912, 0.961, P = 0.045). The AUCs of the Cirrus OCT were significantly higher than those of GDx VCC in all parameters. Most of the parameters in Cirrus OCT were more sensitive than GDx VCC in the detection of glaucoma at fixed specificity values. Cirrus OCT had an infinite LR with abnormal classification results in both average and superior RNFL thickness. There was good agreement between the two instruments with respect to abnormal classifications (kappa, 0.611-0.766) Conclusion: Both Cirrus OCT and GDx VCC RNFL measurements showed good glaucoma diagnostic capabilities. Cirrus OCT showed higher sensitivities than GDx VCC. [ABSTRACT FROM AUTHOR]

Optical coherence tomography (OCT) and scanning laser polarimetry (GDx ECC) are non-invasive methods used to assess retinal nerve fiber layer (RNFL) thickness, which may be a reliable tool used to monitor axonal loss in multiple sclerosis (MS). The objectives of this study are (1) to compare OCT with the GDx ECC; (2) to assess and compare the RNFL thickness in subgroups of MS. Ophthalmologic examination and RNFL assessment by OCT and GDx were performed in 65 MS patients (26 relapsing-remitting (RRMS), ten secondary-progressive (SPMS), 29 primary-progressive (PPMS)). Twenty-eight patients (43%) had a history of optic neuritis (ON). Adjustments were made for age and disease duration. RNFL thickness was reduced in eyes with previous ON ( p < 0.01). No differences were found between PPMS and relapse-onset MS. OCT and GDx ECC measurements were moderately correlated (rho = 0.73, p < 0.01). Visual field-mean deviation (MD) values correlated with OCT means ( r = 0.44, p < 0.01) and GDx ECC TSNIT average ( r = 0.41, p < 0.01). In patients without previous ON, EDSS correlated with MD ( r = −0.36, p < 0.01), visual field-pattern standard deviation (PSD) ( r = 0.30, p < 0.05), OCT means ( r = −0.31-0.30, p < 0.05) and macular volume ( r = −0.37, p < 0.01). For MSIS-29 physical impact score, significant correlations were found with MD ( r = −0.48, p < 0.01) and PSD ( r = 0.48, p < 0.01). Conclusions: No differences between PPMS and relapse-onset MS subgroups were found. RNFL thickness was reduced in eyes with previous ON. Although OCT and GDx ECC findings were moderately correlated and showed significant correlations with measures of visual function in patients without previous ON, EDSS correlated significantly with visual and OCT measures, but not with GDx ECC. [ABSTRACT FROM AUTHOR]

Glaucoma is characterized by a typical appearance of the optic disc and peripheral visual field loss. However, diagnosis may be challenging even for an experienced clinician due to wide variability among normal and glaucomatous eyes. Standard automated perimetry is routinely used to establish the diagnosis of glaucoma. However, there is evidence that substantial retinal ganglion cell damage may occur in glaucoma before visual field defects are seen. The introduction of newer imaging devices such as confocal scanning laser ophthalmoscopy, scanning laser polarimetry and optical coherence tomography for measuring structural changes in the optic nerve head and retinal nerve fiber layer seems promising for early detection of glaucoma. New functional tests may also help in the diagnosis. However, there is no evidence that a single measurement is superior to the others and a combination of tests may be needed for detecting early damage in glaucoma. [ABSTRACT FROM AUTHOR]

To evaluate the impact of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), on retinal nerve fiber layer (RNFL) measurements, by means of scanning laser polarimetry (SLP) GDx VCC (with variable corneal compensation). Two groups of 119 myopic patients each were treated by PRK and LASIK respectively; one eye of each patient was randomly selected for the study. RNFL measurements (around the entire calculation circle) was performed in all eyes 1 day before and 1, 3, 6 and 12 months after treatment by using SLP GDx VCC. Corneal compensation was performed in all eyes preoperatively, and in every examination step postoperatively, in order to neutralize the new corneal birefringence. No statistical differences were found between the PRK and LASIK groups, in all preoperative and postoperative RNFL measurements. Only the p values for CCT and mean K-readings preoperatively were statistically significant. PRK and LASIK do not seem to influence the RNFL measurements at 1st, 3rd, 6th and 12th postoperative months when measured with SLP GDx VCC. The corneal compensation reset is necessary in every step of the examination in order to have reproducible results. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare scanning laser polarimetry measurements of retinal nerve fibre layer (RNFL) thickness in eyes of migraine patients with those in eyes of age-matched, healthy subjects. Methods: The study was designed as an observational, prospective, cross-sectional study. It included 57 eyes of 57 patients with migraine with or without aura according to the criteria of the International Headache Society and 44 eyes of 44 age-matched healthy controls. Scanning laser polarimetry images were obtained using a commercial GDx VCC system (Version 5.3.1; Laser Diagnostic Technologies, Inc.). At each sitting, three sets of GDx VCC measurements were acquired for each patient and used in the analysis. Image acquisition was performed in undilated eyes in all subjects. Results: The mean ± standard deviation RNFL average thickness parameter in the migraine subjects was significantly lower than in the control group, at 50.4 ± 4.8 μm versus 54.7 ± 3.4 μm, respectively (p < 0.0001). However, there were no differences between migraine subjects and controls in mean RNFL thickness in superior and inferior areas. In the migraine group the mean migraine disability assessment (MIDAS) score was 34.3 ± 15.3 and the mean number of attacks per year was 17.1 ± 6.9 (range 6−28). The mean RNFL average thickness parameter was significantly correlated with MIDAS score ( r = − 0.86, p < 0.0001) and frequency of attacks ( r = − 0.86, p < 0.0001). Conclusions: The mean RNFL average thickness parameter was found to be thinner in migraine patients. In addition, we found a strong correlation between migraine severity and RNFL average thickness parameters. [ABSTRACT FROM AUTHOR]

PurposeTo assess the prevalence of atypical retardation pattern (ARP) in scanning laser polarimetry (SLP) with variable corneal compensation (VCC) and enhanced corneal compensation (ECC), and to evaluate the factors relating to typical scan score (TSS).MethodsMeasurements of SLP–VCC, SLP–ECC, and the Humphrey field analyzer (HFA) were performed in 105 normal subjects and 82 open-angle glaucoma (OAG) patients. ARP was defined as an SLP image with TSS<80.ResultsPrevalence of ARP with SLP–VCC was 13.3 and 14.6% in normal and OAG eyes, respectively, and that with SLP–ECC (2.9% and 1.2%) was lower than SLP–VCC (P<0.009). TSS with SLP–VCC was significantly correlated with age (partial correlation coefficient (PCC)=−0.22, P=0.003) and refractive error (PCC=0.26, P<0.001) after adjusting for each other. TSS with SLP–ECC was significantly correlated with neither age nor refractive error (PCC=−0.02, P=0.788; PCC=0.10, P=0.177, respectively). In OAG eyes, mean deviation (MD) of HFA was significantly correlated with TSS with SLP–VCC and SLP–ECC (PCC=0.35, P=0.001; PCC=0.23, P=0.039, respectively). In SLP-VCC, MD was significantly correlated with retinal nerve fibrr layer (RNFL) thickness only after excluding eyes with ARP (P<0.001).ConclusionsARP in SLP–VCC measurements was found in more than 10% of normal or glaucomatous eyes, and TSS was significantly lower in older subjects, more myopic eyes, or eyes with more advanced glaucomatous damage. The presence of ARP disturbs the accuracy of RNFL thickness measurement by SLP–VCC. In SLP–ECC measurements, prevalence of ARP was considerably lower and TSS was not affected by age or refractive error, suggesting the advantages of ECC in clinical practices. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: The aim of this study was to analyze glaucomatous eyes that show discordance between structure and function and hypothesize plausible anatomical explanations for discordance. Methods: Fifty eyes from 50 consecutive subjects with glaucoma (which was diagnosed according to multicenter criteria) were studied. One eye from each subject was selected randomly for inclusion, counterbalancing right eye (O.D.) and left eye (O.S.). By comparing the available structural information (from clinical disc assessment as well as GDx retinal nerve fiber layer [RNFL] measurements) to the Swedish Interactive Threshold Algorithm (SITA) Standard 24-2 (SS24-2) visual field results, study eyes were assigned to the following categories: (1) positive structure-function correlation, (2) structural abnormalities with no functional deficits, and (3) functional abnormalities with no structural deficits. Structure and function also were compared on a statistical basis, utilizing the nerve fiber indicator (NFI) of the GDx and the mean deviation (MD) and pattern standard deviation (PSD) of SS24-2 visual fields. Results: Forty-four eyes were classified in category 1, 5 eyes in category 2, and 1 eye in category 3. Scatter plots showing the relationship between the NFI and MD and between the NFI and PSD depict a positive correlation in the 44 category 1 eyes with R2 values of 0.465 and 0.322, respectively. The remaining 6 eyes with discordant structural and functional findings were analyzed in detail. Conclusion: The majority (88%) of glaucoma cases show concordance between structural loss and functional deficits. The primary proposed explanations for discordance include (1) visual field sampling and test selection limitations (i.e., the SS24-2 samples only axons that are anatomically connected to photoreceptors in the central retina, whereas the GDx samples virtually all axons) and (2) GDx measurement limitations in the papillo-macula bundle (i.e., the GDx has difficulty differentiating the normally thin RNFL from the pathologically even thinner RNFL). Tests of both structure and function are recommended in glaucoma suspects and patients, as neither mode is capable of identifying all glaucomatous deficits. Due to the apparent diagnostic benefit that the peripheral functional data may provide, we strongly recommend that future studies evaluating the structure–function relationship in glaucoma record peripheral (60-4) visual fields for all subjects at the outset of the study. [Copyright &y& Elsevier]

Purpose: We aimed to determine prospectively the incidence of abnormal test results on frequency doubling perimetry (FDT), the nerve fibre analyser (GDx) and standard automated perimetry (SAP) in a cohort of glaucoma suspect patients with normal findings for all these tests at baseline. Methods: Seventy glaucoma suspect patients were followed prospectively for 4 years with SAP (Humphrey field analyser 30-2 SITA Fast), FDT (C-20 full-threshold) and GDx (Version 2.010) in a clinical setting. All patients had normal baseline test results on SAP, FDT and GDx. After the follow-up period, the number of patients who converted (whose test results changed from normal at baseline to reproducibly abnormal during follow-up) were counted for each technique and then compared. The cut-off point for FDT was > 1 depressed test-point p < 0.01 in the total deviation probability plot; the cut-off point for GDx was the Number > 29. Results: Of the 70 glaucoma suspect patients, three converted on FDT, 14 on GDx and six on SAP. These proportions are significantly different for GDx versus SAP (p = 0.033) and GDx versus FDT (p = 0.002), but not for FDT versus SAP (p = 0.256). Conclusions: The most frequent finding after a 4-year follow-up was conversion on GDx. [ABSTRACT FROM AUTHOR]

Purpose To calculate and validate a linear discriminant function (LDF) for scanning laser polarimetry (SLP) with variable corneal compensation (GDx-VCC) to increase the diagnostic accuracy when using isolated retinal nerve fibre layer (RNFL) parameters to discriminate between healthy and glaucomatous eyes with visual field loss.Methods We prospectively selected two independent samples (teaching and validating sets). The teaching set, comprising 71 consecutive healthy subjects and 73 patients with open-angle glaucoma, was used to calculate the LDF. The validating set, comprising 72 consecutive normal eyes and 76 glaucoma patients, was used to test the performance of the LDF in an independent population. Receiver operating characteristic (ROC) curves were plotted for the validating set to evaluate the diagnostic accuracy of the LDF and the SLP parameters.Results The obtained function was LDF=−12.20+(0.15 × nasal average)−(23.85 × normalized inferior area)+(1.18 × maximum modulation). The areas under the ROC curve were 0.901 and 0.893 for our LDF and 0.893 and 0.877 for the nerve fibre indicator (NFI) in the teaching and validating populations, respectively. There were no significant differences between these values (P=0.743 in the teaching set, and P=0.458 in the validating set). NFI was the SLP-provided parameter with the best sensitivity–specificity balance. Sensitivities were 57.89% for the LDF and 48.68% for NFI at 95% fixed specificity.Conclusions The LDF and NFI were the most accurate SLP parameters for diagnosing glaucoma. The LDF yielded the highest sensitivity at 95% fixed specificity to discriminate between normal and glaucoma subjects.Eye (2009) 23, 593–600; doi:10.1038/eye.2008.50; published online 29 February 2008 [ABSTRACT FROM AUTHOR]

PurposeTo verify whether scanning laser polarimeter with the new variable corneal compensation algorithm (GDx VCC) and scanning laser ophthalmoscopy (Heidelberg Retina Tomograph (HRT)) allow measuring retinal ganglion cell loss in patients with multiple sclerosis (MS).Patients and methodsWe enrolled 23 MS patients with a history of previous demyelinating monocular optic neuritis. Examination included visual evoked potentials (VEPs), scanning laser ophthalmoscopy, and scanning laser polarimeter. HRT was performed to assess optic nerve head (ONH) shape, while GDx VCC was used to evaluate the retinal nerve fibre layer thickness (RNFLt) around the ONH. Statistical analysis was performed comparing results obtained for each eye with the available normative database and with the unaffected fellow eye.ResultsWhen the affected eye group was compared to the fellow-eye group, a significant (P<0.05) difference was found for few GDx VCC parameters. In contrast, no significant correlation was observed between clinical assessment and imaging techniques when the normal database of HRT and GDx VCC was used. A significant association was observed between VEP latency and some GDx VCC parameters.ConclusionsOur results suggested that scanning laser polarimetry could detect loss of ganglion cells following demyelinating optic neuritis, but further studies are needed.Eye (2009) 23, 407–412; doi:10.1038/sj.eye.6703013; published online 9 November 2007 [ABSTRACT FROM AUTHOR]

PurposeA feasibility study comparing retinal nerve fibre layer (RNFL) thickness values obtained with imaging devices against RNFL thickness measurements obtained histologically in a human eye.DesignA single patient scheduled for orbital exenteration, who still possessed a healthy functioning eye.MethodsBefore surgery, the eye was imaged using optical coherence tomography (OCT) and scanning laser polarimetry (SLP). After orbital exenteration, the globe was sectioned, and 100 equidistant RNFL thickness measurements were obtained for each of four concentric rings centred on the optic disc, with diameters of 3.0, 3.5, 4.0, and 4.5 mm.ResultsRNFL thickness was found to be inversely related to the distance from the centre of the optic disc along each radial meridian. Peripapillary RNFL thickness was found comparable for histology, OCT, and SLP. RNFL thickness measured histologically confirmed a ‘double hump’ pattern, peaking at the superior and inferior poles. Histologically derived RNFL thickness (μm), at 3.0 and 3.5 mm diameter ring ranged between 30–135 and 25–115 respectively. In comparison, the 3.0 mm diameter GDx data ranged between 25 and 100, and the 3.4 mm diameter OCT data between 40 and 175.ConclusionsImaging data appear qualitatively similar when compared to the histologically derived data. Quantitative differences may be partly due to scaling differences and histological artefacts. The histological analysis approach demonstrated in this study can potentially serve to validate imaging-derived data, as well as help improve our understanding of RNFL loss in glaucoma.Eye (2009) 23, 171–175; doi:10.1038/sj.eye.6702942; published online 24 August 2007 [ABSTRACT FROM AUTHOR]

Copyright of Journal of Optometry is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)