Displaying publications 1 - 20 of 30 in total

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  1. Ch'ng TW, Gillmann K, Hoskens K, Rao HL, Mermoud A, Mansouri K
    Eye (Lond), 2020 03;34(3):562-571.
    PMID: 31409906 DOI: 10.1038/s41433-019-0560-6
    OBJECTIVES: To determine the effect of surgical intraocular pressure (IOP) lowering on peripapillary retinal nerve fibre layer thickness (RNFL), fovea avascular zone (FAZ), peripapillary and macular vessel density (VD) in glaucoma using with optical coherence tomography angiography (OCT-A).

    METHODS: This was a prospective observational study performed at the Glaucoma Research Centre, Montchoisi Clinic, Lausanne. In total 40 eyes with open-angle glaucoma were included. OCT-A scans were performed before glaucoma surgery, and at 1-month, 3-month, 6-month, and 12-month post-operatively. AngioVue AngioAnalytic (Optovue Inc, Fremont, CA) software was used to analyse the RNFL, FAZ, peripapillary and macular VD. Changes were analysed using analysis of variance (ANOVA) models.

    RESULTS: Mean IOP dropped from 19.4 (±7.0) mmHg pre-surgery and stabilized at 13.0 (±3.1) mmHg at 12 months (p 

    Matched MeSH terms: Nerve Fibers
  2. New SH, Leow SN, Vasudevan SK, Idris IB, Tang SF, Din NM
    PLoS One, 2021;16(2):e0246830.
    PMID: 33630879 DOI: 10.1371/journal.pone.0246830
    OBJECTIVE: To evaluate the retinal nerve fiber layer (RNFL) and macular thicknesses and identify systemic risk factors for thinning of these layers in patients with metabolic syndrome (MetS).

    METHODOLOGY: A cross-sectional observational study was performed on patients diagnosed with MetS and compared to normal controls. All patients underwent ophthalmic and anthropometric examination, serological and biochemical blood investigations; and ocular imaging using spectral-domain optical coherence tomography. Patients with ocular pathology were excluded. Unpaired t-test was used to compare mean thickness between the two groups. One-way ANOVA with Bonferroni correction for multiple comparisons was used to compare mean thickness between different tertiles of MetS parameters, and a generalized estimating equation was used to correct for inter-eye correlation and to assess association between mean thickness and covariates.

    RESULTS: Two hundred and forty-eight eyes from 124 participants (1:1 ratio of MetS patients to controls) were included. Age ranged between 30 to 50 years old, and mean age was 40 ± 6.6 years. RNFL thickness was lower globally (93.6 ± 9.9 μm vs 99.0 ± 9.3, p<0.001) and in the inferior (124.5 ± 17.5 μm vs 131.0 ± 16.4 μm, p = 0.002), superior (117.2 ± 16.0 μm vs 126.3 ± 14.4 μm, p<0.001) and temporal (65.5 ± 10.2 μm vs 69.5 ± 9.8, p = 0.002) sectors in MetS patients compared to controls. Only the central (237.0 ± 14.0 μm vs 243.6 ± 18.0 μm, p = 0.002) and inferior parafoveal (307.8 ± 20.9 vs 314.6 ± 14.6, p = 0.004) area of the macula was significantly thinner. The inferior RNFL sector had the most difference (mean difference = 9.1 μm). The Generalized Estimating Equation found that, after adjusting for age, diastolic blood pressure, BMI, HDL and obesity; the number of MetS components and elevated triglyceride levels were independent risk factors for reduced thickness in global RNFL (β = -4.4, 95% CI = -7.29 to -1.5, p = 0.003) and inferior parafovea (β = -6.85, 95% CI = -11.58 to -2.13, p = 0.004) thickness respectively.

    CONCLUSION: RNFL thinning was seen more than macula thinning in MetS patients, suggesting RNFL susceptibility to neurodegeneration than the macula. A higher number of metabolic components and elevated triglyceride levels were independent risk factors for retinal thinning in this group of patients.

    Matched MeSH terms: Nerve Fibers/pathology*
  3. Wang L, Tan H, Yu J, ZhangBao J, Huang W, Chang X, et al.
    Eur J Neurol, 2023 Feb;30(2):443-452.
    PMID: 36286605 DOI: 10.1111/ene.15612
    BACKGROUND AND PURPOSE: The aim was to evaluate the potential of retinal nerve fiber layer thickness (RNFLT) measured with optical coherence tomography in predicting disease progression in relapsing-remitting multiple sclerosis (RRMS).

    METHODS: Analyses were conducted post hoc of this 24-month, phase III, double-blind study, in which RRMS patients were randomized (1:1:1) to once daily oral fingolimod 0.5 mg, 1.25 mg or placebo. The key outcomes were the association between baseline RNFLT and baseline clinical characteristics and clinical/imaging outcomes up to 24 months. Change of RNFLT with fingolimod versus placebo within 24 months and time to retinal nerve fiber layer (RNFL) thinning were evaluated.

    RESULTS: Altogether 885 patients were included. At baseline, lower RNFLT was correlated with higher Expanded Disability Status Scale score (r = -1.085, p = 0.018), lower brain volume (r = 0.025, p = 0.006) and deep gray matter volume (r = 0.731, p 

    Matched MeSH terms: Nerve Fibers/pathology
  4. Maheshwari S, Kanhangad V, Pachori RB, Bhandary SV, Acharya UR
    Comput Biol Med, 2019 Feb;105:72-80.
    PMID: 30590290 DOI: 10.1016/j.compbiomed.2018.11.028
    BACKGROUND AND OBJECTIVE: Glaucoma is a ocular disorder which causes irreversible damage to the retinal nerve fibers. The diagnosis of glaucoma is important as it may help to slow down the progression. The available clinical methods and imaging techniques are manual and require skilled supervision. For the purpose of mass screening, an automated system is needed for glaucoma diagnosis which is fast, accurate, and helps in reducing the burden on experts.

    METHODS: In this work, we present a bit-plane slicing (BPS) and local binary pattern (LBP) based novel approach for glaucoma diagnosis. Firstly, our approach separates the red (R), green (G), and blue (B) channels from the input color fundus image and splits the channels into bit planes. Secondly, we extract LBP based statistical features from each of the bit planes of the individual channels. Thirdly, these features from the individual channels are fed separately to three different support vector machines (SVMs) for classification. Finally, the decisions from the individual SVMs are fused at the decision level to classify the input fundus image into normal or glaucoma class.

    RESULTS: Our experimental results suggest that the proposed approach is effective in discriminating normal and glaucoma cases with an accuracy of 99.30% using 10-fold cross validation.

    CONCLUSIONS: The developed system is ready to be tested on large and diverse databases and can assist the ophthalmologists in their daily screening to confirm their diagnosis, thereby increasing accuracy of diagnosis.

    Matched MeSH terms: Nerve Fibers
  5. Bakri MM, Yahya F, Munawar KMM, Kitagawa J, Hossain MZ
    Arch Oral Biol, 2018 May;89:94-98.
    PMID: 29499561 DOI: 10.1016/j.archoralbio.2018.02.011
    OBJECTIVE: Transient receptor potential vanilloid 4 (TRPV4) has been considered as a mechano-, thermo- and osmo-receptor. Under inflammatory conditions in dental pulp, teeth can become sensitive upon exposure to a variety of innocuous stimuli. The objective of the present study was to investigate the expression of the TRPV4 channel on nerve fibers in human dental pulp of non-symptomatic and symptomatic teeth associated with inflammatory conditions.

    DESIGN: Dental pulp from extracted human permanent teeth was processed for fluorescence immunohistochemistry. Ten asymptomatic (normal) and 10 symptomatic (symptoms associated with pulpitis) teeth were used in this study. Nerve fibers were identified by immunostaining for a marker, protein gene product 9.5, and the cells were counterstained with 4',6-diamidino-2-phenylindole. An anti-TRPV4 antibody was used to trace TRPV4 expression.

    RESULTS: TRPV4 expression was co-localized with the nerve fiber marker. Immunoreactivity for TRPV4 was more intense (p 

    Matched MeSH terms: Nerve Fibers/metabolism*; Nerve Fibers/pathology
  6. Ngoo QZ, A NF, A B, Wh WH
    Korean J Ophthalmol, 2021 06;35(3):223-230.
    PMID: 34120421 DOI: 10.3341/kjo.2020.0019
    PURPOSE: To study the retinal nerve fiber layer (RNFL) thickness and optic nerve head (ONH) parameters in obstructive sleep apnoea (OSA) patients and their relationship with severity of the disease.

    METHODS: A cross-sectional, hospital-based study. Fifty-four OSA subjects and 54 controls were recruited. Candidate that fulfil the criteria with normal ocular examinations then proceed with spectrum domain Cirrus optical coherence tomography examinations. ONH parameters and RNFL thickness were evaluated. Apnoea-hypopnoea index (AHI) of the OSA group were obtained from the medical record.

    RESULTS: In OSA, mean of average RNFL thickness was 93.87 µm, standard deviation (SD) = 9.17, p = 0.008 (p < 0.05) while superior RNFL thickness was 113.59 µm, SD = 16.29, p ≤ 0.001 (p < 0.05). RNFL thickness fairly correlate with severity of the disease (AHI), superior RNFL with R = 0.293, R2 = 0.087, p = 0.030 (p < 0.05), and nasal RNFL R = 0.292, R2 = 0.085, p = 0.032. No significant difference and correlation observed on ONH parameters. In control group, mean of average RNFL thickness was 98.96 µm, SD = 10.50, p = 0.008 (p < 0.05) while superior RNFL thickness was 125.76 µm, SD = 14.93, p ≤ 0.001 (p < 0.05).

    CONCLUSIONS: The mean of the average and superior RNFL thickness were significantly lower in the OSA group compare to control. Regression analysis showed RNFL thickness having significantly linear relationship with the AHI, specifically involving the superior and nasal quadrant.

    Matched MeSH terms: Nerve Fibers
  7. Loh KB, Rahmat K, Lim SY, Ramli N
    Neurol India, 2011 Mar-Apr;59(2):266-9.
    PMID: 21483130 DOI: 10.4103/0028-3886.79143
    A "Hot Cross Bun" sign on T2-weighted MRI was described as a result of selective loss of myelinated transverse pontocerebellar fibers and neurons in the pontine raphe with preservation of the pontine tegmentum and corticospinal tracts (CST). However, neuropathologic studies showed contradicting results with no sparing of the CST. This is a pictorial and quantitative demonstration of the sign on diffusion tensor imaging and tractography, which provides the imaging evidence that is consistent with neuropathologic findings.
    Matched MeSH terms: Nerve Fibers, Myelinated/pathology*
  8. Neoh YL, Neoh PF, Salleh A, Yusof ZB, Gurusamy B, Ahmad Tajudin LS
    Ann Acad Med Singap, 2018 06;47(6):226-229.
    PMID: 30019068
    Matched MeSH terms: Nerve Fibers/pathology*
  9. Ling KP, Mangalesh S, Tran-Viet D, Gunther R, Toth CA, Vajzovic L
    Retina, 2020 Oct;40(10):1996-2003.
    PMID: 31764609 DOI: 10.1097/IAE.0000000000002688
    BACKGROUND/PURPOSE: Using handheld spectral domain optical coherence tomography (SDOCT) imaging to investigate in vivo microanatomic retinal changes and their progression over time in young children with juvenile X-linked retinoschisis (XLRS).

    METHODS: This retrospective analysis was of handheld SD OCT images obtained under a prospective research protocol in children who had established XLRS diagnosis based on genetic testing or clinical history. Three OCT graders performed standardized qualitative and quantitative assessment of retinal volume scans, which were divided into foveal, parafoveal, and extrafoveal regions. Visual acuity data were obtained when possible.

    RESULTS: Spectral domain OCT images were available of both eyes in 8 pediatric patients with ages 7 months to 10 years. The schisis cavities involved inner nuclear layer in over 90% (15/16) of eyes in all 3 regions. Retinal nerve fiber and ganglion cell layer involvement was present only in the extrafoveal region in 63% (10/16) eyes and outer nuclear and plexiform layer in few others. In 7 children followed over 2 months to 15 months, the location of schisis remained consistent. Central foveal thickness decreased from the baseline to final available visit in 4/6 eyes. Ellipsoid zone disruption seemed to accompany lower visual acuity in 1/4 eyes.

    CONCLUSION: Early in life, the SD OCT findings in XLRS demonstrate differences in schisis location in fovea-parafoveal versus extrafoveal region, possible association between poor visual acuity and degree of ellipsoid zone disruption and decrease in central foveal thickness over time in this group. Furthermore, they illustrates that the pattern of XLRS in adults is already present in very young children, and unlike in older children and adults, those presenting with earlier disease may have a more aggressive course. Further studies in this early age group may provide more insights into treatment and prevention of progressive visual impairment in children with XLRS.

    Matched MeSH terms: Nerve Fibers/pathology
  10. Loh KB, Ramli N, Tan LK, Roziah M, Rahmat K, Ariffin H
    Eur Radiol, 2012 Jul;22(7):1413-26.
    PMID: 22434420 DOI: 10.1007/s00330-012-2396-3
    OBJECTIVES: The degree and status of white matter myelination can be sensitively monitored using diffusion tensor imaging (DTI). This study looks at the measurement of fractional anistropy (FA) and mean diffusivity (MD) using an automated ROI with an existing DTI atlas.

    METHODS: Anatomical MRI and structural DTI were performed cross-sectionally on 26 normal children (newborn to 48 months old), using 1.5-T MRI. The automated processing pipeline was implemented to convert diffusion-weighted images into the NIfTI format. DTI-TK software was used to register the processed images to the ICBM DTI-81 atlas, while AFNI software was used for automated atlas-based volumes of interest (VOIs) and statistical value extraction.

    RESULTS: DTI exhibited consistent grey-white matter contrast. Triphasic temporal variation of the FA and MD values was noted, with FA increasing and MD decreasing rapidly early in the first 12 months. The second phase lasted 12-24 months during which the rate of FA and MD changes was reduced. After 24 months, the FA and MD values plateaued.

    CONCLUSION: DTI is a superior technique to conventional MR imaging in depicting WM maturation. The use of the automated processing pipeline provides a reliable environment for quantitative analysis of high-throughput DTI data.

    KEY POINTS: Diffusion tensor imaging outperforms conventional MRI in depicting white matter maturation. • DTI will become an important clinical tool for diagnosing paediatric neurological diseases. • DTI appears especially helpful for developmental abnormalities, tumours and white matter disease. • An automated processing pipeline assists quantitative analysis of high throughput DTI data.

    Matched MeSH terms: Nerve Fibers, Myelinated/physiology*; Nerve Fibers, Myelinated/ultrastructure*
  11. Sidek S, Ramli N, Rahmat K, Ramli NM, Abdulrahman F, Kuo TL
    Eur Radiol, 2016 Dec;26(12):4404-4412.
    PMID: 26943134
    OBJECTIVE: To compare the metabolite concentration of optic radiation in glaucoma patients with that of healthy subjects using Proton Magnetic Resonance Spectroscopy (1H-MRS).

    METHODS: 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 × 20 × 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA.

    RESULTS: The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05).

    CONCLUSION: Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients.

    KEY POINTS: • Glaucoma disease has a neurodegenerative component. • Metabolite changes have been observed in the neurodegenerative process in the brain. • Using SVS, no metabolite changes in optic radiation were attributed to glaucoma.

    Matched MeSH terms: Nerve Fibers/metabolism; Nerve Fibers/pathology
  12. Ramli K, Gasim AI, Ahmad AA, Htwe O, Mohamed Haflah NH, Law ZK, et al.
    Tissue Eng Part A, 2019 10;25(19-20):1438-1455.
    PMID: 30848172 DOI: 10.1089/ten.TEA.2018.0279
    We investigated the efficacy of a muscle-stuffed vein (MSV) seeded with neural-transdifferentiated human mesenchymal stem cells as an alternative nerve conduit to repair a 15-mm sciatic nerve defect in athymic rats. Other rats received MSV conduit alone, commercial polyglycolic acid conduit (Neurotube®), reverse autograft, or were left untreated. Motor and sensory functions as well as nerve conductivity were evaluated for 12 weeks, after which the grafts were harvested for histological analyses. All rats in the treatment groups demonstrated a progressive increase in the mean Sciatic Functional Index (motor function) and nerve conduction amplitude (electrophysiological function) and showed positive withdrawal reflex (sensory function) by the 10th week of postimplantation. Autotomy, which is associated with neuropathic pain, was severe in rats treated with conduit without cells; there was mild or no autotomy in the rats of other groups. Histologically, harvested grafts from all except the untreated groups exhibited axonal regeneration with the presence of mature myelinated axons. In conclusion, treatment with MSV conduit is comparable to that of other treatment groups in supporting functional recovery following sciatic nerve injury; and the addition of cells in the conduit alleviates neuropathic pain. Impact Statement It is shown that pretreated muscle-stuffed vein conduit is comparable to that of commercial nerve conduit and autograft in supporting functional recovery following peripheral nerve injury. The addition of neural-differentiated mesenchymal stem cells in the conduit is shown to alleviate neuropathic pain.
    Matched MeSH terms: Nerve Fibers/metabolism; Nerve Fibers/ultrastructure
  13. Goh. SY, Ropilah, AR, Othmaliza, O, Mushawiahti, M
    MyJurnal
    Diabetic retinopathy is a disease involving microangiopathic changes in response to chronic hyperglycaemia and pan retinal photocoagulation (PRP) is currently the mainstay of treatment for proliferative retinopathy. In the present study, we evaluated the effect of pan retinal photocoagulation (PRP) on retinal nerve fibre layer (RNFL) thickness in patients with diabetic retinopathy using optical coherence tomography (OCT). This was a prospective longitudinal study. Patients with Type 2 diabetes mellitus with proliferative diabetic retinopathy (PDR) or very severe non-(N)PDR requiring laser treatment were included in the study. PRP was performed by a single trained personnel. Peripapillary RNFL located 3.4 mm around the optic disc was evaluated using time-domain OCT. Examination was performed before treatment, and 2 and 4 months after laser treatment. In total, 39 subjects (39 eyes) were recruited into this study. Twenty-nine patients had PDR and 10 had very severe NPDR. Mean age was 54.97 ± 8.38 years. Male and female genders were almost equally distributed with 18 males and 21 females. Median thickness of average RNFL at baseline was 108.8 um (interquartile range [IQR] 35.3). At two months post-procedure, average RNFL thickness significantly increased to 117.4 (IQR 28.6; P = 0.006). Although, other quadrants revealed a similar trend of increasing thickness at two months but it was not significant. At 4 months post-laser treatment, RNFL thickness in all quadrants reduced to baseline levels with insignificant changes of thickness compared to prior to laser treatment. There was also no significant association between changes in RNFL thickness and HbA1c levels (P = 0.77). In conclusion, PRP causes transient thickening of the RNFL which recovers within 4 months post-laser treatment. At the same time, poor sugar control has no direct influence on the RNFL changes after PRP.
    Matched MeSH terms: Nerve Fibers
  14. Mohd-Ilham I, Tai ELM, Suhaimi H, Shatriah I
    Korean J Ophthalmol, 2021 08;35(4):287-294.
    PMID: 34162187 DOI: 10.3341/kjo.2020.0106
    PURPOSE: There are limited data from Asian countries regarding retinal thickness in children with type 1 diabetes mellitus (T1DM). This study aimed to compare the macular and retinal nerve fiber layer (RNFL) parameters between diabetic children without retinopathy and non-diabetic healthy children. We also evaluated the factors associated with RNFL thickness in children with T1DM.

    METHODS: A comparative cross-sectional study was conducted among children with T1DM and healthy children aged 7 to 17 years old in Hospital Universiti Sains Malaysia from 2017 to 2019. Children with retinal disease or glaucoma were excluded. Macular and RNFL thicknesses were measured using spectral-domain optical coherence tomography. Demographic information, duration of diabetes, blood pressure, body mass index, visual acuity, and retinal examination findings were documented. Glycosylated hemoglobin levels, renal function, and blood lipid levels were also collected.

    RESULTS: Forty-one children with T1DM and 80 age- and sex-matched children were enrolled. Both sexes were affected. Mean duration of diabetes mellitus was 3.66 years. The mean glycated hemoglobin levels in the T1DM group was 9.99%. The mean macular and RNFL thicknesses in children with T1DM were 277.56 (15.82) µm and 98.85 (12.05) µm, respectively. Children with T1DM had a significantly thinner average macula, superior outer macula, nasal outer macula, mean RNFL, and inferior RNFL thickness compared to controls (p < 0.05). There was a significant association between nephropathy and the mean RNFL thickness.

    CONCLUSIONS: Children with T1DM had significantly decreased mean macular and RNFL thicknesses. Nephropathy is associated with an increased RNFL thickness.

    Matched MeSH terms: Nerve Fibers
  15. Lee WW, Tajunisah I, Sharmilla K, Peyman M, Subrayan V
    Invest Ophthalmol Vis Sci, 2013 Nov;54(12):7785-92.
    PMID: 24135757 DOI: 10.1167/iovs.13-12534
    We determined structural retinal nerve fiber layer (RNFL) changes in schizophrenia patients and established if the structural changes were related to the duration of the illness using spectral-domain optical coherence tomography (SD-OCT).
    Matched MeSH terms: Nerve Fibers/pathology*
  16. Hye Khan MA, Abdul Sattar M, Abdullah NA, Johns EJ
    Exp. Toxicol. Pathol., 2007 Nov;59(3-4):253-60.
    PMID: 17764917
    The pathogenesis of cisplatin-induced renal failure is related to reduced renal blood flow due to severe tubular damage and enhanced renovascular resistance. It is also known that alpha(1)-adrenoceptors, the major subtype of alpha-adrenoceptors in renal vasculature play the pivotal role in regulating renal hemodynamics. With this background, we have hypothesized that the altered renal hemodynamics and enhanced renovascular resistance in cisplatin-induced renal failure might be caused by the altered alpha-adrenergic responsiveness with a possible involvement of alpha(1)-adrenoceptors in the renal vasculature. In a unique experimental approach with anesthetized rats, this study has therefore examined if there is any shift in the renovascular responsiveness to renal nerve stimulation and a series of alpha-adrenergic agonists in Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats with cisplatin-induced renal failure in comparison with their body weight-matched normal controls. Thirty-two male rats of both WKY (n=16) and SHR (n=16) origin with body weight 236+/-7.9 g received cisplatin (5mg/kg i.p.). The renal failure was confirmed in terms of significantly reduced renal blood flow, reduced creatinine clearance, increased fractional excretion of sodium, increased kidney index (all P<0.05) and tubular damage. After 7 days of cisplatin, the overnight fasted rats were anesthetized (sodium pentobarbitone, 60 mg/kg i.p.) and renal vasoconstrictor experiments were done. The changes in the vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by electrical renal nerve stimulation or intrarenal administration of noradrenaline, phenylephrine and methoxamine. It was observed that in the cisplatin-treated renal failure WKY and SHR rats there were significant (all P<0.05) reductions in the renal blood flow along with significantly (P<0.05) higher renal adrenergic responsiveness as compared with their non-renal failure controls. The data showed that in the renal failure WKY and SHR rats, the altered renal hemodynamics might be caused by an augmented renal adrenergic responsiveness. The results obtained further led us to suggest that the augmented renal adrenergic responsiveness in the cisplatin-induced renal failure rats were possibly mediated by the alpha(1)-adrenoceptors.
    Matched MeSH terms: Nerve Fibers/drug effects; Nerve Fibers/physiology
  17. Din NM, Taylor SR, Isa H, Tomkins-Netzer O, Bar A, Talat L, et al.
    JAMA Ophthalmol, 2014 Jul;132(7):859-65.
    PMID: 24789528 DOI: 10.1001/jamaophthalmol.2014.404
    IMPORTANCE: Uveitic glaucoma is among the most common causes of irreversible visual loss in uveitis. However, glaucoma detection can be obscured by inflammatory changes.

    OBJECTIVE: To determine whether retinal nerve fiber layer (RNFL) measurement can be used to detect glaucoma in uveitic eyes with elevated intraocular pressure (IOP).

    DESIGN, SETTING, AND PARTICIPANTS: Comparative case series of RNFL measurement using optical coherence tomography performed from May 1, 2010, through October 31, 2012, at a tertiary referral center. We assigned 536 eyes with uveitis (309 patients) in the following groups: normal contralateral eyes with unilateral uveitis (n = 72), normotensive uveitis (Uv-N) (n = 143), raised IOP and normal optic disc and/or visual field (Uv-H) (n = 233), and raised IOP and glaucomatous disc and/or visual field (Uv-G) (n = 88).

    EXPOSURES: Eyes with uveitis and elevated IOP (>21 mm Hg) on at least 2 occasions.

    MAIN OUTCOMES AND MEASURES: Comparison of RNFL values between groups of eyes and correlation with clinical data; risk factors for raised IOP, glaucoma, and RNFL thinning.

    RESULTS: Mean (SD) global RNFL was thicker in Uv-N (106.4 [21.4] µm) compared with control (96.0 [9.0] µm; P 

    Matched MeSH terms: Nerve Fibers/pathology*
  18. Salih QA, Ramli AR, Mahmud R, Wirza R
    MedGenMed, 2005;7(2):1.
    PMID: 16369380
    Different approaches to gray and white matter measurements in magnetic resonance imaging (MRI) have been studied. For clinical use, the estimated values must be reliable and accurate when, unfortunately, many techniques fail on these criteria in an unrestricted clinical environment. A recent method for tissue clusterization in MRI analysis has the advantage of great simplicity, and it takes the account of partial volume effects. In this study, we will evaluate the intensity of MR sequences known as T1-weighted images in an axial sliced section. Intensity group clustering algorithms are proposed to achieve further diagnosis for brain MRI, which has been hardly studied. Subjective study has been suggested to evaluate the clustering group intensity in order to obtain the best diagnosis as well as better detection for the suspected cases. This technique makes use of image tissue biases of intensity value pixels to provide 2 regions of interest as techniques. Moreover, the original mathematic solution could still be used with a specific set of modern sequences. There are many advantages to generalize the solution, which give far more scope for application and greater accuracy.
    Matched MeSH terms: Nerve Fibers, Myelinated/pathology*
  19. Md Din N, Tomkins-Netzer O, Talat L, Taylor SR, Isa H, Bar A, et al.
    J Glaucoma, 2016 07;25(7):598-604.
    PMID: 26900824 DOI: 10.1097/IJG.0000000000000379
    PURPOSE: To determine risk factors for intraocular pressure (IOP) elevation and glaucoma in children with nonjuvenile idiopathic arthritis-related uveitis and any IOP-related changes in the retinal nerve fiber layer (RNFL) thickness.

    PATIENTS AND METHODS: Clinical data were collected from children attending a tertiary referral uveitis clinic between May 2010 and October 2012. We assigned 206 eyes of 103 children into 32 normal eyes, 108 normotensive uveitics (NU), 41 hypertensive uveitics (HU: raised IOP without glaucomatous disc), and 25 glaucomatous uveitics (GU: raised IOP with glaucomatous disc). Risk factors for raised IOP, glaucoma and steroid response (SR) were evaluated and RNFL thickness across groups was compared with determine changes related to raised IOP.

    RESULTS: IOP elevation occurred in 40 patients (38.8%) or 66/174 eyes with uveitis (37.9%); and SR occurred in 35.1% of all corticosteroid-treated eyes. Chronic uveitis was a significant risk factor for raised IOP [odds ratio (OR)=9.28, P=0.001], glaucoma, and SR (OR=8.4, P<0.001). Higher peak IOP was also a risk factor for glaucoma (OR=1.4, P=0.003). About 70% of SR eyes were high responders (IOP increase >15 mm Hg from baseline), associated with younger age and corticosteroid injections. Although no significant RNFL thinning was detected between HU and NU eyes, significant thinning was detected in the inferior quadrant of GU (121.3±28.9 μm) compared with NU eyes (142.1±32.0 μm, P=0.043).

    CONCLUSIONS: Children with chronic uveitis are at higher risk of raised IOP and glaucoma. Thinning of the inferior RNFL quadrant may suggest glaucomatous changes in uveitic children with raised IOP.

    Study site: Moorfields Eye Hospital, London
    Matched MeSH terms: Nerve Fibers/pathology*
  20. Chai X, Low KY, Tham YC, Chee ML, Thakur S, Zhang L, et al.
    Invest Ophthalmol Vis Sci, 2020 08 03;61(10):37.
    PMID: 32821913 DOI: 10.1167/iovs.61.10.37
    Purpose: Genome-wide association studies have identified several genes associated with glaucoma. However, their roles in the pathogenesis of glaucoma remain unclear, particularly their effects on retinal nerve fiber layer (RNFL) thickness. The aim of this study was to investigate the associations between the identified glaucoma risk genes and RNFL thickness.

    Methods: A total of 3843 participants (7,020 healthy eyes) were enrolled from the Singapore Epidemiology of Eye Diseases (SEED) study, a population-based study composing of three major ethnic groups-Malay, Indian, and Chinese-in Singapore. Ocular examinations were performed, and spectral-domain optical coherence tomography (SD-OCT) was used to measure circumpapillary RNFL thickness. We selected 35 independent glaucoma-associated genetic loci for analysis. An linear regression model was conducted to determine the association of these variants with circumpapillary RNFL, assuming an additive genetic model. We conducted association analysis in each of the three ethnic groups, followed by a meta-analysis of them.

    Results: The mean age of the included participants was 59.4 ± 8.9 years, and the mean RFNL thickesss is 92.3 ± 11.2 µm. In the meta-analyses, of the 35 glacuoma loci, we found that only SIX6 was significantly associated with reduction in global RNFL thickness (rs33912345; β = -1.116 um per risk allele, P = 1.64E-05), and the effect size was larger in the inferior RNFL quadrant (β = -2.015 µm, P = 2.9E-6), and superior RNFL quadrant (β = -1.646 µm, P = 6.54E-5). The SIX6 association were consistently observed across all three ethnic groups. Other than RNFL, we also found several genetic varaints associated with vertical cuo-to-disc ratio (ATOH7, CDKN2B-AS1, and TGFBR3-CDC7), rim area (SIX6 and CDKN2B-AS1), and disc area (SIX6, ATOH7, and TGFBR3-CDC7). The association of SIX6 rs33912345 with NRFL thickness remained similar after further adjusting for disc area and 3 other disc parameter associated SNPs (ATOH7, CDKN2B-AS1, and TGFBR3-CDC7).

    Conclusions: Of the 35 glaucoma identified risk loci, only SIX6 is significantly and independently associated with thinner RNFL. Our study further supports the involvement of SIX6 with RNFL thickness and pathogensis of glaucoma.

    Matched MeSH terms: Nerve Fibers/pathology
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