Nerve Fiber Layer Thickness Research Articles

Comparison of Retinal Changes Following Silicone Oil and Perfluoropropane Gas Tamponade for Proliferative Diabetic Retinopathy Patients.

Purpose: To investigate the different tamponade effects of intravitreal silicone oil (SO) and perfluoropropane gas on the retinal structure and vasculature in proliferative diabetic retinopathy (PDR) patients. Methods: Thirty-eight eligible patients (47 eyes) with PDR requiring pars plana vitrectomy (PPV) were enrolled in the prospective observational study. Subjects were divided into two groups after PPV: SO group subjects underwent SO tamponade, whereas Gas group subjects underwent perfluoropropane gas tamponade. The primary outcomes of this study were longitudinal changes in retinal structure and vasculature between 10 and 90 days after the operation. Secondary outcomes were longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thickness between 10 and 90 days after the operation in each sector. Results: Thirty-six eyes of 27 patients with a median age of 56.6 ± 9.8 years completed follow-up and were statistically analyzed. No significant difference in demographics or clinical characteristics was found between the two groups. Eyes in the SO group had a statistically significant decrease in pRNFL thickness at 90 days after PPV (p < 0.001), and there was a significant intergroup difference compared with the Gas group (p = 0.001), except for the temporal sector. Eyes in the Gas group had a statistically significant increase in parafoveal vessel density (VD) of the superficial vascular complex (SVC) at 90 days after PPV (p = 0.023), although there was no significant intergroup difference. The type of tamponade, changes in full retina thickness, and parafoveal SVC VD showed a significant correlation with changes in pRNFL thickness (all p < 0.05). Conclusion: SO tamponade resulted in a significantly greater decrease in pRNFL over 90 days than gas tamponade in patients with PDR. In addition, the change in the pRNFL was significantly correlated with changes in full retina thickness and SVC VD after the operation.

Changes in circumpapillary retinal nerve fiber layer thickness after vitrectomy for rhegmatogenous retinal detachment

The study aimed to evaluate the long-term changes in circumpapillary retinal nerve fiber layer (RNFL) thickness after vitrectomy for rhegmatogenous retinal detachment (RRD) repair. A total of 33 eyes of 33 patients were enrolled. By using optical coherence tomography, the circumpapillary RNFL thickness was measured before surgery and 1, 3, 6 months and 1, 2, 3 years after surgery and compared with the preoperative value. The effect of duration, location, and extent of RRD on RNFL thickness change was evaluated. There was a significant increase of circumpapillary RNFL thickness at the 1-month, 3-month [except in the nasal superior sector (P = 0.627)], and only in the nasal inferior sector at 6-month (P = 0.010) follow-up compared with the baseline value (all Ps < 0.05). No significant differences were observed 1, 2, and 3 years after the surgery (P > 0.05). The duration, location, and extent of detachment did not reveal significant correlations with RNFL parameters (P > 0.05). Circumpapillary RNFL thickness in eyes with RRD after vitrectomy demonstrated a transient increase during the early postoperative period. This increase was not associated with duration, location, and extent of RRD. At 3 years following surgery, no RNFL thinning or thickening was observed.

Quantifying biomarkers of axonal degeneration in early glaucoma to find the disc at risk

To evaluate regional axonal-related parameters as a function of disease stage in primary open angle glaucoma (POAG) and visual field (VF) sensitivity. Spectral domain optical coherence tomography was used to acquire 20° scans of POAG (n = 117) or healthy control (n = 52) human optic nerve heads (ONHs). Region specific and mean nerve fibre layer (NFL) thicknesses, border NFL and peripapillary NFL, minimum rim width (MRW)/ area (MRA) and prelamina thickness; and volume were compared across POAG disease stages and with visual field sensitivity. Differences identified between early glaucoma (EG), preperimetric glaucoma (PG) and control (C) ONHs included thinner PG prelamina regions than in controls (p < 0.05). Mean border NFL was thinner in EG (p < 0.001) and PG (p = 0.049) compared to control eyes; and EG mean, and inferior and ST, border NFL was thinner than in PG (p < 0.01). Mean, superior and inferior PG peripapillary NFL were thinner than in controls (p < 0.05), and EG ST peripapillary NFL was thinner than in PG (p = 0.023). MRW differences included: PG SN and inferior less than in controls (p < 0.05); thinner EG mean regional, inferior, nasal, and ST MRW versus PG MRW (p < 0.05). Regional border NFL, peripapillary NFL, MRW, MRA, prelamina thickness (except centre, p = 0.127) and prelamina volume (p < 0.05) were significantly associated with VF mean deviation (MD). Novel axon-derived indices hold potential as biomarkers to detect early glaucoma and identify ONHs at risk.

Structural retinal changes in cerebral small vessel disease

Cerebral small vessel disease (CSVD) is an important contributor to cognitive impairment and stroke. Previous research has suggested associations with alterations in single retinal layers. We have assessed changes of all individual retinal layers in CSVD using high-resolution optical coherence tomography (OCT) for the first time. Subjects with recent magnetic resonance imaging (MRI) underwent macular and peripapillary retinal imaging using OCT for this case–control study. Number and volume ratio index (WMRI) of white matter lesions (WML) were determined on MRI. Data were analyzed using multiple linear regression models. 27 CSVD patients and 9 control participants were included. Ganglion cell layer (GCL) volume was significantly reduced in patients with CSVD compared to age-matched controls (p = 0.008). In patients with CSVD, larger foveal outer plexiform layer (OPL) volume and decreased temporal peripapillary retinal nerve fiber layer (RNFL) thickness were significantly associated with a higher WMRI in linear regression when controlling for age (p ≤ 0.033). Decreased foveal GCL volume and temporal-inferior RNFL thickness at Bruch’s membrane opening (MRW), and increased temporal MRW were associated with a higher WML burden (p ≤ 0.037). Thus, we identified alterations in several OCT layers in individuals with CSVD (GCL, OPL, MRW and RNFL). Their potential diagnostic value merits further study.

Thickened Retinal Nerve Fiber Layers Associated With High-Altitude Headache.

Purpose: This study aimed to quantify the different quadrants of the optic nerve head (ONH) and macular parameters and their changes during exposure to high altitude, and to assess their correlation with high-altitude headache (HAH). Methods: Spectral-domain optical coherence tomography (OCT) was used to quantify changes in the retinal structure in 109 healthy subjects during acute exposure to high altitude (3,700 m). Self-reported symptoms of HAH and acute mountain sickness AMS were assessed using Lake Louise Score (LLS), alongside measurements of physiological parameters (oxygen saturation [SpO2], heart rate [HR], hemoglobin level [Hb], and red blood cell [RBC] count). Measurements were taken before and after exposure to the high-altitude environment. The correlations of these parameters and changes at ONH were examined. Results: With the exposure to high altitude, the incidence of AMS was 44.0% and the frequency of HAH was 67.0% (54.1% mild, 12.9% moderate-severe). As for systemic parameters measured at high altitude, the participants exhibited significantly lower SpO2, higher resting HR, higher Hb, and a higher RBC (all p < 0.05). Key stereometric parameters used to describe ONH [superior, inferior, nasal, temporal, and mean retinal nerve fiber layer (RNFL) thickness] and macula (macular thickness) increased at high altitude compared with baseline. Most parameters of ONH changed, especially superior, inferior, and mean RNFL thickness (p < 0.05). There was a significant correlation between the ratios of RNFL at ONH and HAH [mean thickness (r = 0.246, p = 0.01); inferior (r = 0.216, p = 0.02); nasal (r = 0.193, p = 0.04)]. No associations between parameters of ONH and AMS or LLS were observed. Conclusion: The high-altitude environment can increase RNFL thickness at ONH. Furthermore, we found that the ratios of mean thickness, inferior area, and nasal area correlated positively with HAH, which provides new insights for understanding of the underlying pathological mechanisms of high-altitude retinopathy (HAR).

Platelet Parameters and Their Relationships With the Thickness of the Retinal Nerve Fiber Layer and Ganglion Cell Complex in Primary Open-Angle Glaucoma.

ObjectiveGlaucoma is a neurodegenerative disease of the visual system. Platelet parameters are correlated with visual field mean deviation (MD) in glaucoma, but there is a lack of relative data on their relationship with structural changes in the retina. This study aimed to explore the relationship between platelet parameters and retinal nerve fiber layer (RNEL), ganglion cell complex (GCC) thickness, and cup/disk area ratio, evaluated by optical coherence tomography (OCT) in primary open-angle glaucoma (POAG).MethodsA total of 118 consecutive patients with POAG and 120 age- and sex-matched control subjects were included in this retrospective study. Demographic data, platelet parameters in blood tests, visual field, and OCT results were evaluated. The RNFL was divided into the temporal, superior, nasal, and inferior quadrants. Based on the visual field MD, the patients were stratified into mild (MD ≤ 6.0 dB), moderate (6 dB < MD ≤ 12 dB), and severe (MD > 12.0 dB) subgroups.ResultsPatients with POAG had significantly lower platelet (PLT) levels and significantly higher platelet distribution width (PDW) and mean platelet volume (MPV) levels than controls. As the visual field MD increased, structural evaluation by OCT identified loss of disk rim area, average GCC thickness, and average RNFL thickness (all P < 0.001), as well as increased PDW (P < 0.001) and MPV (P = 0.004) levels in patients with POAG. The Spearman's rank correlation analysis showed that PDW levels were significantly correlated with OCT parameters such as RNFL thickness (r = −0.370, P < 0.001), GCC thickness (r = −0.294, P = 0.001), and cup/disk area ratio (r = 0.322, P < 0.001), as well as visual field MD (r = 0.607, P < 0.001) and mean sensitivity (MS) (r = −0.570, P < 0.001). Significantly correlations were also found between MPV and RNFL thickness (r = −0.321, P < 0.001), GCC thickness (r = −0.194, P = 0.041), and cup/disk area ratio (r = 0.237, P = 0.010). All the quadrants showed similar negative correlations between PDW, MPV, and RNFL thickness. The multiple linear regression analyses showed significant association between PDW and RNFL thickness (β = −0.331, P < 0.001), PDW and GCC thickness (β = −0.288, P = 0.002), MPV and RNFL thickness (β = −0.313, P = 0.001), and MPV and GCC thickness (β = −0.188, P = 0.048).ConclusionThis study found significantly negative association between PDW, MPV levels and RNFL, GCC thickness, as well as positive association between PDW, MPV levels, and cup/disk area ratio in patients with POAG, suggesting that platelet activation may contribute to glaucomatous optic neuropathy.

Structural and functional differentiation between compressive and glaucomatous optic neuropathy

Clinical diagnoses of slow, progressive, painless visual losses with various degrees of visual field (VF) losses and disc atrophy are often confused between suprasellar compressive optic neuropathy (CON) and open-angle glaucomatous optic neuropathy (GON). We plotted the thickness of the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) against the mean deviation (MD) of the VF of 34 eyes of CON at diagnosis, 30 eyes of CON after therapy, 29 eyes of GON, and 60 eyes of healthy controls in a cross-sectional investigation. At diagnosis, a disproportionally early pattern of structural thinning compared with the corresponding VF losses was unique to CON. GON- and CON-specific thinning parameters were generally useful in differentiating GON and CON from moderate to severe MD losses, but early MD losses (0 to − 6 dB) overlapped with GON in a CON-stage specific manner. GON-specific thinning parameters, RNFL in the inferior sector, and inferior to temporal macular GCIPL ratio showed overlap with posttreatment CON in the early MD losses with AUCs of 0.916 (95% CI 0.860–0.971; P < 0.001) and 0.890 (95% CI 0.811–0.968; P < 0.001), respectively. In comparison, CON-specific thinning parameters, superonasal, and inferonasal GCIPL showed overlap with CON at diagnosis for early MD losses. Overall, the nasal-to-temporal macular GCIPL ratio showed good discrimination between CON and GON throughout the MD range, with an AUC of 0.923 (95% CI 0.870–0.976; P < 0.001). Comparing GON with all stages of CON, the cut-point of 0.95 showed the lower nasal-to-temporal GCIPL ratio had a sensitivity of 72% and specificity of 90% for CON. However, the cut-point of 1.10 showed the superior-to-inferior GCIPL ratio had a sensitivity of 60% and specificity of 98% for GON.

Parafoveal and peripapillary vessel density in pediatric and juvenile craniopharyngioma patients

We assessed the retinal microvascular alterations detected by optical coherence tomography angiography (OCT-A) in pediatric and juvenile craniopharyngioma (CP) patients with chiasmal compression. We included 15 eyes of 15 pediatric or juvenile CP patients and 18 eyes of 18 healthy subjects. The evaluation of vessel density from the superficial retinal capillary plexus (SRCP), the deep retinal capillary plexus, and the radial peripapillary capillary (RPC) segments was obtained by OCT-A. The association between vessel density measures and functional and structural measurements was also analyzed. There were significant reductions in the nasal sector of the SRCP (p < 0.0001) and all sectors of the RPC segment vessel density (nasal, temporal, and superior; p < 0.0001, inferior; p = 0.0015) in CP patients postoperatively compared to the healthy subjects. The peripapillary retinal nerve fiber layer (r = 0.6602, p = 0.0074) and ganglion cell-inner plexiform layer thicknesses (r = 0.7532, p = 0.0030) were associated with RPC segment vessel density. Visual acuity (r = − 0.5517, p = 0.0330) and temporal visual field sensitivity loss (r = 0.5394, p = 0.0465) showed an association with SRCP vessel density. In pediatric and juvenile patients with CP, parafoveal and peripapillary vascular changes following chiasmal compression were observed. The changes in vascular structures were closely related to structural and functional outcomes.

Peripapillary Nerve Fiber Layer Thickness and Optic Nerve Head Parameters in Patients Recovered from COVID-19: A Longitudinal Study.

Purpose To quantify the longitudinal changes of the optic nerve head (ONH) parameters and peripapillary retinal nerve fiber layer (pRNFL) thickness in patients recovered from coronavirus disease 2019 (COVID-19) using spectral-domain optical coherence tomography (OCT) analysis. Materials and Methods In an observational longitudinal study, in patients recovered from COVID-19, ONH OCT images were recorded at least two weeks after recovery from the systemic disease as the baseline and after one and three-month follow-up. Ganglion cell complex (GCC) analysis, ONH parameters, and pRNFL thickness changes were measured. Results A total of 36 eyes from 18 recovered COVID-19 patients including eleven (61.2%) females were studied. The average age was 35.5 ± 7.5 years. The pRNFL thickness in the nasal lower sector significantly decreased from 77 ± 18 μm in the first post-COVID-19 month to 74 ± 10 μm in the third month (P=0.8). The average, superior, and inferior pRNFL thickness remained unchanged. The average cup volume significantly decreased from 0.27 ± 0.15 mm3 at baseline to 0.19 ± 0.15 mm3 in the third post-COVID-19 visit (P=0.028). In terms of ONH morphologies including rim, disc and cup to disc area, and the vertical and horizontal ratio, the changes were not significant over the 3-month study period. Focal loss volume and global loss volume values were not changed significantly. Conclusion Localized defect in the nasal lower sector of pRNFL is observed in 3-month post-recovery from COVID-19. Larger studies with longer follow-ups are required to reveal the exact changes in ONH parameters.

Some anatomical parameters of the eyes of patients with different stages of glaucoma

Purpose: to study the morphological structures of the eyes of patients with primary open-angle glaucoma (POAG) and to identify the changes characteristic of this disease.Material and methods. We examined 90 patients with various stages of POAG and compensated ophthalmic tonus and 50 patients without glaucoma with ophthalmic pathology not associated with eye hydrodynamic disorders (control group), aged 40 to 81 years and older. In addition to the standard ophthalmological examination, all patients were examined for the curvature of the anterior surface of the cornea and its thickness, the depth of the anterior chamber and the thickness of the lens, the length of the eye axis, the thickness of the retinal nerve fiber layer (RNFL) and the condition of the optic nerve head (ONH), using ophthalmometry, keratotopography, anterior segment analyzer (Pentacam, OCULUS, USA), ultrasound biometry (UD-6000 Tomey, Japan), and optical coherence tomography (OCT).Results. No significant differences in the parameters of ultrasound biometry and pachymetry were revealed between the control group and POAG patients. The only types of data characterizing the glaucoma process were altered parameters of the optic disc and the peripapillary zone of the retina, namely, the thickness of the RNFL. In 81.1 % of glaucoma eyes, temporal excavation was detected, the average RNFL thickness in the temporal segment of the ONH was 44.2 ± 3.0 μm.Conclusion. Ophthalmoscopy and OCT of the ONH and RNFL are the main diagnostic methods that allow obtaining indisputable data on the morphological changes characteristic of POAG. These studies should become mandatory in the diagnosis of glaucoma and monitoring of patients with POAG..

Функциональные особенности зрительного анализатора у пациентов с хронической ишемической нейрооптикопатией, ассоциированной с гемодинамически значимым атеросклеротическим стенозом внутренней сонной артерии, после проведенной каротидной эндартерэктомии

Purpose. To evaluate effect of carotid endarterectomy (CE) in long-term follow-up period on course of chronic ischemic optic neuropathy (CION) associated with hemodynamically significant atherosclerotic internal carotid artery (ICA) stenosis. Material and methods. The object of study was 30 patients (30 eyes) with CION associated with hemodynamically significant atherosclerotic ICA stenosis. All patients underwent study of visual evoked potential (VEP), optical coherence tomography, Doppler ultrasonography of ophthalmic artery (OA) before and after ICA CE. Results. By the end of observation period (12 months), in patients with CION, despite the improvement blood flow in OA, there was deterioration in VEP and decrease in the thickness of the peripapillary retinal nerve fiber layer, the cause of which can be considered imbalance of energy metabolism that negatively affects the ganglion cells axons, leading to their death. Conclusion. Our studies show that further studies are needed to study the effect of ICA CE on the course of CION. Keywords: chronic ischemic optic neuropathy, ocular ischemic syndrome, hemodynamically significant internal carotid artery stenosis, visual evoked potential, optical coherence tomography.

Ocular manifestations of systemic isotretinoin in patients with acne: a systemic review and meta-analysis

Purpose To examine the effects of systemic isotretinoin treatment on the eye using several ocular examination parameters. Methods We conducted a systemic review for literature published up to June 2021 in both PubMed and Web of Science databases. We included prospective observational or interventional studies evaluating ocular manifestations of isotretinoin in acne patients. The primary outcome measures were anaesthetized and non-anaesthetized Schirmer test, tear break-up time (TBUT), central corneal thickness (CCT), average retinal nerve fibre layer (RNFL) thickness, ganglion cell-inner plexiform layer (GC-IP) thickness, subfoveal choroidal thickness, axial length, ocular surface disease index (OSDI), meibomian gland expression (MGE) and conjunctival stain. The National Institute of Health (NIH) quality assessment tools were used to assess the data quality. The effect size used to analyse the included studies was the weighted mean difference (WMD) and its related confidence intervals (95%CIs). Results Twenty-one publications involving 1105 eyes of 842 participants met the inclusion criteria. Isotretinoin use was significantly associated with reduction in the scores of anaesthetized Schirmer (WMD = –2.23, 95%CI: −3.28 to −1.18), non-anaesthetized Schirmer (WMD = –3.74, 95%CI: −4.23 to −3.25), TBUT (WMD = –3.47, 95%CI: −5.09 to −1.86), and CCT (WMD= −7.39, 95%CI: −13.91 to −0.88). Isotretinoin use was significantly associated with increase of OSDI (WMD = 18.29, 95%CI: 7.54–29.03), MGE (WMD = 1.02, 95%CI: 0.70–1.33) and conjunctival stain scores (WMD = 0.61, 95%CI: 0.47–0.76). No significant change was noted in RNFL thickness (WMD = −0.64, 95%CI: −1.80 to 0.51); GC-IP thickness (WMD = 0.42, 95%CI: −1.08 to 1.92); subfoveal choroidal thickness (WMD = –1.80, 95%CI: −6.69 to 3.09), and axial length (WMD = 0.08, 95%CI: −0.19 to 0.35). A significant heterogeneity was found between the study estimates in each of anaesthetized Schirmer, TBUT, MGE, OSDI, and conjunctival stain tests. Conclusion Isotretinoin use results in a statistically significant reduction of the central corneal thickness, TBUT, and Schirmer test scores. A statistically significant increase in MGE, OSDI and conjunctival stain scores was found. No statistically significant change of average RNFL, GC-IP thickness, subfoveal choroidal thickness, or axial length was observed. Further well-designed studies should evaluate the long-term effect of isotretinoin on the eye and reach a firmer conclusion.

Effect of acupuncture on retinal and choroidal thickness in patients with optic atrophy

To observe the effect of acupuncture on visual acuity, intraocular pressure, visual field, retinal and choroidal thickness on optic disc and macular area in patients with optic atrophy. A total of 33 patients with optic atrophy were treated with acupuncture. Acupuncture was given at Chengqi (ST 1), Shangjingming (Extra), Qiuhou (EX-HN 7) and Fengchi (GB 20) etc., 30 min each time, once a day, for 14 days. The visual acuity, intraocular pressure, visual field indexes (mean deviation [MD], pattern standard deviation [PSD] and visual field index [VFI]), optic disc retinal nerve fiber layer thickness, macular retinal thickness and choroidal thickness of optic disc and sub-foveal were compared before and after treatment. Compared before treatment, the visual acuity was increased (P<0.05), the MD value was decreased (P<0.05), the thickness of nerve fiber layer on the upper temporal side of optic disc was thinner (P<0.05), and the choroidal thickness of average, nasal side and lower temporal side of optic disc was increased (P<0.05). There was significant correlation between visual field MD and retinal nerve fiber layer thickness in different quadrants before and after treatment (P<0.01). Acupuncture could improve visual acuity, increase choroidal thickness in part of optic disc area in patients with optic atrophy.

A multi-regression framework to improve diagnostic ability of optical coherence tomography retinal biomarkers to discriminate mild cognitive impairment and Alzheimer\u2019s disease

BackgroundDiagnostic performance of optical coherence tomography (OCT) to detect Alzheimer’s disease (AD) and mild cognitive impairment (MCI) remains limited. We assessed whether compensating the circumpapillary retinal nerve fiber layer (cpRNFL) thickness for multiple demographic and anatomical factors as well as the combination of macular layers improves the detection of MCI and AD.MethodsThis cross-sectional study of 62 AD (n = 92 eyes), 108 MCI (n = 158 eyes), and 55 cognitively normal control (n = 86 eyes) participants. Macular ganglion cell complex (mGCC) thickness was extracted. Circumpapillary retinal nerve fiber layer (cpRNFL) measurement was compensated for several ocular factors. Thickness measurements and their corresponding areas under the receiver operating characteristic curves (AUCs) were compared between the groups. The main outcome measure was OCT thickness measurements.ResultsParticipants with MCI/AD showed significantly thinner measured and compensated cpRNFL, mGCC, and altered retinal vessel density (p < 0.05). Compensated RNFL outperformed measured RNFL for discrimination of MCI/AD (AUC = 0.74 vs 0.69; p = 0.026). Combining macular and compensated cpRNFL parameters provided the best detection of MCI/AD (AUC = 0.80 vs 0.69; p < 0.001).Conclusions and relevanceAccounting for interindividual variations of ocular anatomical features in cpRNFL measurements and incorporating macular information may improve the identification of high-risk individuals with early cognitive impairment.

Evaluation of iris epithelial and stromal thickness in patients with migraine by using optical coherence tomography

Objective: The amount of light reaching to the retina is an important factor for photophobia formation. Therefore, investigation of iris thickness in patients with migraine can be valuable for revealing their susceptibility to photophobia. In this study, it was aimed to evaluate the iris epithelial and stromal thickness, retinal ganglion cell layer (RGCL) thickness, and retinal nerve fibre layer (RNFL) thickness of patients with migraine. Methods: Forty-nine migraine patients (Group 1) and 50 control participants (Group 2) were included into this study. For obtaining standard measure in all participants, the epithelial and stromal thickness of dilatory and sphincter iris muscle was measured from the equal distance to the pupillary margin by using anterior segment mode of optical coherence tomography (AS-OCT). Additionally, RNFL and RGCL thicknesses were measured by using posterior segment mode of OCT (PS-OCT). Results: The epithelial thickness of iris sphincter muscle and the epithelial thickness of iris dilatory muscle was found to be significantly higher in patients with migraine compared to control subjects (p&lt;0.001, p=0.001 respectively). Additionally the stromal thickness of both iris sphincter and iris dilatory muscle (p&lt;0.001, p&lt;0.001 respectively) as well as the total thickness of iris sphincter and iris dilatory muscle was significantly higher in patients with migraine than control subjects (p&lt;0.001, p=0.02 respectively). However, no significant difference was found between patients with migraine and control subjects in terms of RNFL and RGCL thicknesses (p=0.1 and p=0.7 respectively). Conclusion: The finding of high epithelial and stromal iris thickness in patients with migraine may support the possible role of increased pupillary dynamic in photophobia formation.

Optical coherence tomography in patients with Parkinson\u2019s disease

BackgroundThe changes in the different retinal layers in Parkinson’s disease (PD) patients can be easily assessed using optical coherence tomography (OCT). Our aim was to evaluate retinal structural changes in patients with PD using OCT. Structural measurements of the retinal nerve fiber layer (RNFL), macular and ganglion cell complex (GCC) thicknesses were obtained using spectral domain optical coherence tomography. Disease severity was assessed using Unified Parkinson Disease Rating Scale (UPDRS).ResultsRetinal nerve fiber layer parameters, except for the superonasal and inferonasal quadrants, were significantly reduced in PD patients compared to controls. All macular parameters and GCC thickness were also reduced in PD patients compared to controls. Hoehn and Yahr (HY) staging was inversely correlated with all macular parameters, GCC and temporal RNFL thicknesses. UPDRS score showed a significant negative correlation with macular volume, inferior and nasal parafoveal thicknesses, nasal and temporal RNFL thicknesses and GCC thickness. The disease duration was inversely correlated with macular volume, inferior and temporal parafoveal thicknesses and GCC thickness. Using the multivariate linear regression analysis, the HY scale was a significant predictor for both the average GCC thickness and the macular volume. The sensitivity and specificity of average GCC thickness and macular volume to detect disease severity were 58.8%, 86.7%, 64.7% and 86.7%, respectively.ConclusionParkinson’s disease causes axonal damage in the RNFL along with retinal thinning that can be detected using SD-OCT. Patients with greater axonal damage tend to have longer duration of the disease and more severe PD symptoms.

Optical coherence tomography and visual evoked potentials in evaluation of optic chiasm decompression

Chiasmal compression is a known cause of visual impairment, often leading to surgical decompression of the optic chiasm (OC). A prospective study was held at University Hospital in Hradec Králové to explore sensitivity of optical coherence tomography (OCT) and visual evoked potentials (VEPs) to OC compression and eventual changes after a decompression. 16 patients with OC compression, caused by different sellar pathologies, were included. The main inclusion criterion was the indication for decompressive surgery. Visual acuity (VA), visual field (VF), retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) thickness, and peak time and amplitude of pattern-reversal (P-VEPs) and motion-onset VEPs (M-VEPs) were measured pre- and postoperatively. The degree of OC compression was determined on preoperative magnetic resonance imaging. For M-VEPs, there was a significant postoperative shortening of the peak time (N160) (p < 0.05). P100 peak time and its amplitude did not change significantly. The M-VEPs N160 amplitude showed a close relationship to the VF improvement. Thinner preoperative RNFL does not present a statistically important limiting factor for better functional outcomes. The morphological status of the sellar region should be taken into consideration when one evaluates the chiasmal syndrome. M-VEPs enable detection of functional changes in the visual pathway better than P-VEPs.

Optical coherence tomography in neurodegenerative disorders.

Structural imaging of the brain is the most widely used diagnostic tool for investigating neurodegenerative diseases. More advanced structural imaging techniques have been applied to early or prodromic phases, but they are expensive and not widely available. Therefore, it is highly desirable to search for noninvasive, easily accessible, low-cost clinical biomarkers suitable for large-scale population screening, in order to focus on making diagnoses at the earliest stages of the disease. In this scenario, imaging studies focusing on the structures of the retina have increasingly been used for evaluating neurodegenerative diseases. The retina shares embryological, histological, biochemical, microvascular and neurotransmitter similarities with the cerebral cortex, thus making it a uniquely promising biomarker for neurodegenerative diseases. Optical coherence tomography is a modern noninvasive imaging technique that provides high-resolution two-dimensional cross-sectional images and quantitative reproducible three-dimensional volumetric measurements of the optic nerve head and retina. This technology is widely used in ophthalmology practice for diagnosing and following up several eye diseases, such as glaucoma, diabetic retinopathy and age-related macular degeneration. Its clinical impact on neurodegenerative diseases has raised enormous interest over recent years, as several clinical studies have demonstrated that these diseases give rise to reduced thickness of the inner retinal nerve fiber layer, mainly composed of retinal ganglion cells and their axons. In this review, we aimed to address the clinical utility of optical coherence tomography for diagnosing and evaluating different neurodegenerative diseases, to show the potential of this noninvasive and easily accessible method.

Half-fluence photodynamic therapy in peripapillary circumscribed choroidal haemangiomas.

To evaluate the safety and efficacy of half-fluence photodynamic therapy (PDT) as treatment for symptomatic peripapillary circumscribed choroidal haemangiomas (CCHs). In this prospective, interventional case series; 11 patients with symptomatic peripapillary CCHs presenting to a single centre were treated with half-fluence PDT using verteporfin 6mg/m2 with fluence of 25mJ/cm2 (standard is 50mJ/cm2) and other standard settings. Patients were evaluated at baseline, four weeks, twelve weeks and twenty-four weeks post-PDT treatment with best corrected visual acuity (BCVA), ultrasonography, spectral domain optical coherence tomography (SD-OCT), visual evoked potential and angiographic studies. Eleven patients with peripapillary CCHs received half-fluence PDT. The BCVA significantly improved to 0.558 ± 0.118 at four weeks post-treatment (P = 0.014), to 0.494 ± 0.114 at twelve weeks (P = 0.006) and 0.441 ± 0.125 at twenty-four weeks (P = 0.007) from baseline levels of 1.017 ± 0.075 on log MAR scales. Similar improvement was observed in central macular thickness (CMT) of 78.50 ± 13.73 μm (P = 0.001) at four weeks; 114.70 ± 27.73 μm (P = 0.003) at twelve weeks and 174.60 ± 23.13 μm (P = 0.001) at twenty-four weeks post-treatment. A single session of re-treatment was required in 18% (n = 2) of patients which also showed complete resolution at last follow-up. No complications were observed without any significant change in retinal nerve fibre layer (RNFL) thickness at six months follow-up. Half-fluence PDT can be an effective and safe treatment option for peripapillary CCHs which results in both anatomical and functional improvements with no observable complications.

Neuro-ophthalmological evaluation including optical coherence tomography surrounding venous sinus stenting in idiopathic intracranial hypertension with papilledema: a case series

Venous sinus stenting (VSS) for idiopathic intracranial hypertension (IIH) has been demonstrated to achieve significant symptom improvement while harboring a low periinterventional morbidity profile. Comprehensive neuro-ophthalmological monitoring represents a cornerstone of disease monitoring. The value of optical coherence tomography (OCT) requires further exploration. Patients with IIH and papilledema who underwent VSS between 04/2018 and 02/2021 were retrospectively reviewed. Clinical and radiological were analyzed. Neuro-ophthalmological data included visual acuity, visual fields, fundoscopy categorized via Frisén scale, and OCT obtained retinal nerve fiber layer (RNFL) thickness were analyzed. Of 39 IIH patients who underwent cerebral angiography with transverse-sigmoid sinus pressure evaluation, 18 patients with IIH and papilledema underwent 21 transverse-sigmoid sinus stenting (TSST) procedures. After TSST, manometry showed a significant reduction of maximum transverse sinus pressures and trans-stenotic gradient pressures (p = 0.005 and p < 0.001, respectively). Chronic headaches, visual disturbance resolved and pulsatile tinnitus improved significantly. Visual fields remained similar, while papilledema Frisén scales and visual acuity significantly improved. The OCT calculated RNFL thickness significantly decreased in all patients. Stratification according to a minimal-low degree (Frisén 1-2) and moderate-marked degree (Frisén 3-4) papilledema demonstrated a significant reduction of RNFL thickness in both groups. Venous sinus stenting provides favorable clinical and neuro-ophthalmological outcomes. This study demonstrates that neuro-ophthalmologic testing augmented with OCT evaluation provides objective data that can be used as a biomarker for treatment success for managing patients with different extents of papilledema and may inform patient management.