The prone position in COVID-19 impacts the thickness of peripapillary retinal nerve fiber layers and macular ganglion cell layers.

The prone position reduces mortality in severe cases of COVID-19 with acute respiratory distress syndrome. However, visual loss and changes to the peripapillary retinal nerve fiber layer (p-RNFL) and the macular ganglion cell layer and inner plexiform layer (m-GCIPL) have occurred in patients undergoing surgery in the prone position. Moreover, COVID-19-related eye problems have been reported. This study compared the p-RNFL and m-GCIPL thicknesses of COVID-19 patients who were placed in the prone position with patients who were not. This prospective longitudinal and case-control study investigated 15 COVID-19 patients placed in the prone position (the "Prone Group"), 23 COVID-19 patients not in the prone position (the "Non-Prone Group"), and 23 healthy, non-COVID individuals without ocular disease or systemic conditions (the "Control Group"). The p-RNFL and m-GCIPL thicknesses of the COVID-19 patients were measured at 1, 3, and 6 months and compared within and between groups. The result showed that the Prone and Non-Prone Groups had no significant differences in their p-RNFL thicknesses at the 3 follow-ups. However, the m-GCIPL analysis revealed significant differences in the inferior sector of the Non-Prone Group between months 1 and 3 (mean difference, 0.74 µm; P = 0.009). The p-RNFL analysis showed a significantly greater thickness at 6 months for the superior sector of the Non-Prone Group (131.61 ± 12.08 µm) than for the Prone Group (118.87 ± 18.21 µm; P = 0.039). The m-GCIPL analysis revealed that the inferior sector was significantly thinner in the Non-Prone Group than in the Control Group (at 1 month 80.57 ± 4.60 versus 83.87 ± 5.43 µm; P = 0.031 and at 6 months 80.48 ± 3.96 versus 83.87 ± 5.43 µm; P = 0.044). In conclusion, the prone position in COVID-19 patients can lead to early loss of p-RNFL thickness due to rising intraocular pressure, which is independent of the timing of prone positioning. Consequently, there is no increase in COVID-19 patients' morbidity burden.

Quantifying Putative Retinal Gliosis in Preclinical Alzheimer's Disease.

Purpose: Neuroinflammation plays a significant role in the pathology of Alzheimer's disease (AD). Mouse models of AD and postmortem biopsy of patients with AD reveal retinal glial activation comparable to central nervous system immunoreactivity. We hypothesized that the surface area of putative retinal gliosis observed in vivo using en face optical coherence tomography (OCT) imaging will be larger in patients with preclinical AD versus controls. Methods: The Spectralis II instrument was used to acquire macular centered 20 × 20 and 30 × 25-degrees spectral domain OCT images of 76 participants (132 eyes). A cohort of 22 patients with preclinical AD (40 eyes, mean age = 69 years, range = 60-80 years) and 20 control participants (32 eyes, mean age = 66 years, range = 58-82 years, P = 0.11) were included for the assessment of difference in surface area of putative retinal gliosis and retinal nerve fiber layer (RNFL) thickness. The surface area of putative retinal gliosis and RNFL thickness for the nine sectors of the Early Treatment Diabetic Retinopathy Study (ETDRS) map were compared between groups using generalized linear mixed models. Results: The surface area of putative retinal gliosis was significantly greater in the preclinical AD group (0.97 ± 0.55 mm2) compared to controls (0.68 ± 0.40 mm2); F(1,70) = 4.41, P = 0.039; Cohen's d = 0.61. There was no significant difference between groups for RNFL thickness in the 9 ETDRS sectors, P > 0.05. Conclusions: Our analysis shows greater putative retinal gliosis in preclinical AD compared to controls. This demonstrates putative retinal gliosis as a potential biomarker for AD-related neuroinflammation.

Effect of intravitreal injections due to neovascular age-related macular degeneration on retinal nerve fiber layer thickness and minimum rim width: a cross sectional study.

PURPOSE: The present study tested the hypothesis that repeated anti-VEGF injections are associated with reduced retinal nerve fiber layer (RNFL) and minimum rim width (MRW) of the optic nerve head. PATIENTS AND METHODS: Sixty-six patients with a history of intravitreal injections due to neovascular age-related macular degeneration were included. RNFL and MRW were measured using optical coherence tomography (Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany). RESULTS: Mean global RNFL was 90.62 µm and both RNFL as well as MRW significantly decreased with advanced age (p = 0.005 and p = 0.019, respectively). Correlating for the number of injections, no significant impact on RNFL was found globally (p = 0.642) or in any of the sectors. In contrast, however, global MRW was significantly reduced with increasing numbers of intravitreal injections (p = 0.012). The same holds true when adjusted for the confounding factor age (RNFL p = 0.566 and MRW p = 0.023). CONCLUSION: Our study shows that repeated intravitreal injections due to choroidal neovascularization seem to have a deleterious effect on MRW but not on RNFL. This suggests that MRW is a more sensitive marker than RNFL for evaluating the effect of frequent intravitreal injections on the optic nerve head since it seems to be the first structure affected.

Immunohistochemical staining with CD117 and PGP9.5 of excised vestibular tissue from patients with neuroproliferative vestibulodynia.

BACKGROUND: Neuroproliferative vestibulodynia (NPV), a provoked genital pain characterized by severe allodynia and hyperalgesia, is confirmed in excised vestibular tissue by immunohistochemical staining (>8 CD117-positive immunostained cells/100× microscopic field) rather than by hematoxylin and eosin staining. AIM: In this study we sought to assess immunostaining of tissue samples obtained during vestibulectomy surgery and to correlate results with patient outcomes. METHODS: Patients (n = 65) meeting criteria for NPV who underwent vestibulectomy during the period from June 2019 through December 2022 formed the study cohort. We performed assessment of pathology of vestibular tissues by use of immunohistochemical staining, including quantitation of mast cells by CD117 (mast cell marker) and nerve fibers by protein gene product (PGP) 9.5 (neuronal marker). We analyzed 725 photomicrographs of immunostained tissue sections (100× and 200×) by manual counting and computer-assisted histometry and correlated these data to clinical assessments. OUTCOMES: Outcomes included density of CD117 and PGP9.5 immunostaining in the 1:00-11:00 o'clock and 12:00 o'clock vestibular regions, and patient-reported outcomes assessing sexual function, pain, distress, and symptom improvement. RESULTS: All 65 NPV patients (median age 26 years), 45 with lifelong and 20 with acquired NPV, had severe pain documented by PROs and vulvoscopy and had >8 CD117-immunopositive cells/100× microscopic field. Median cell count values were similar in the 1:00-11:00 o'clock and 12:00 vestibular regions (28.5 and 29.5/100× field, respectively). Likewise, the marker) and nerve fibers by protein gene product (PGP) 9.5 (neuronal marker). We analyzed 725 photomicrographs of immunostained tissue sections (100× and 200×) by manual counting and computer-assisted histometry and correlated these data to clinical assessments. OUTCOMES: Outcomes included density of CD117 and PGP9.5 immunostaining in the 1:00-11:00 o'clock and 12:00 o'clock vestibular regions, and patient-reported outcomes assessing sexual function, pain, distress, and symptom improvement. RESULTS: All 65 NPV patients (median age 26 years), 45 with lifelong and 20 with acquired NPV, had severe pain documented by PROs and vulvoscopy and had >8 CD117-immunopositive cells/100× microscopic field. Median cell count values were similar in the 1:00-11:00 o'clock and 12:00 vestibular regions (28.5 and 29.5/100× field, respectively). Likewise, the median area of CD117 immunostaining was similar in both regions (0.69% and 0.73%). The median area of PGP9.5 immunostaining was 0.47% and 0.31% in these same regions. Pain scores determined with cotton-tipped swab testing were nominally higher in lifelong vs acquired NPV patients, reaching statistical significance in the 1:00-11:00 o'clock region (P < .001). The median score for the McGill Pain Questionnaire affective subscale dimension was also significantly higher in lifelong vs acquired NPV patients (P = .011). No correlations were observed between hematoxylin and eosin results and density of mast cells or neuronal markers. Of note, 63% of the patient cohort reported having additional conditions associated with aberrant mast cell activity. CLINICAL IMPLICATIONS: The pathology of NPV is primarily localized to the vestibular epithelial basement membrane and subepithelial stroma with no visible vulvoscopic findings, making clinical diagnosis challenging. STRENGTHS AND LIMITATIONS: Strengths of this study include the large number of tissues examined with what is to our knowledge the first-ever assessment of the 12:00 vestibule. Major limitations are specimens from a single timepoint within the disease state and lack of control tissues. CONCLUSIONS: Performing immunohistochemical staining of excised vestibular tissue with CD117 and PGP9.5 led to histometric confirmation of NPV, indications that NPV is a field disease involving all vestibular regions, validation for patients whose pain had been ignored and who had experienced negative psychosocial impact, and appreciation that such staining can advance knowledge.

Gastrointestinal manifestations seen in pediatric patients diagnosed with small fiber neuropathy.

OBJECTIVES: Small fiber neuropathy (SFN) affects the fibers involved in cutaneous and visceral pain and temperature sensation and are a crucial part of the autonomic nervous system. Autonomic dysfunction secondary to SFN and autoimmune receptor antibodies is being increasingly recognized, and gastrointestinal (GI) manifestations include constipation, early satiety, nausea, vomiting, and diarrhea. Enteric nervous system involvement may be a possible explanation of abnormal GI motility patterns seen in these patients. METHODS: Children suspected to have SFN based on symptoms underwent skin biopsy at the Child Neurology clinic at Arnold Palmer Hospital for Children, which was processed at Therapath™ Neuropathology. SFN was diagnosed using epidermal nerve fiber density values that were below 5th percentile from the left distal leg (calf) as reported per Therapath™ laboratory. RESULTS: Twenty-six patients were diagnosed with SFN. Retrospective chart review was performed, including demographic data, clinical characteristics, and evaluation. A majority of patients were white adolescent females. Autonomic dysfunction, including orthostasis and temperature dysregulation were seen in 61.5% of patients (p = 0.124). Somatosensory symptoms, including pain or numbness were seen in 85% of patients (p < 0.001). GI symptoms were present in 85% of patients (p < 0.001) with constipation being the most common symptom seen in 50% of patients. This correlated with the motility testing results. CONCLUSIONS: Pediatric patients with SFN commonly have GI symptoms, which may be the main presenting symptom. It is important to recognize and look for symptoms of small fiber neuropathy in children with refractory GI symptoms that may explain multisystemic complaints often seen in these patients.

Discontinuity third harmonic generation microscopy for label-free imaging and quantification of intraepidermal nerve fibers.

Label-free imaging methodologies for nerve fibers rely on spatial signal continuity to identify fibers and fail to image free intraepidermal nerve endings (FINEs). Here, we present an imaging methodology-called discontinuity third harmonic generation (THG) microscopy (dTHGM)-that detects three-dimensional discontinuities in THG signals as the contrast. We describe the mechanism and design of dTHGM and apply it to reveal the bead-string characteristics of unmyelinated FINEs. We confirmed the label-free capability of dTHGM through a comparison study with the PGP9.5 immunohistochemical staining slides and a longitudinal spared nerve injury study. An intraepidermal nerve fiber (IENF) index based on a discontinuous-dot-connecting algorithm was developed to facilitate clinical applications of dTHGM. A preliminary clinical study confirmed that the IENF index was highly correlated with skin-biopsy-based IENF density (Pearson's correlation coefficient R = 0.98) and could achieve differential identification of small-fiber neuropathy (p = 0.0102) in patients with diabetic peripheral neuropathy.

Educational stereoscopic representation of a step-by-step brain white fiber dissection according to Klingler's method.

BACKGROUND: Understanding and teaching the three-dimensional architecture of the brain remains difficult because of the intricate arrangement of grey nuclei within white matter tracts. Although cortical area functions have been well studied, educational and three-dimensional descriptions of the organization of deep nuclei and white matter tracts are still missing. OBJECTIVE: We propose herein a detailed step-by-step dissection of the lateral aspect of a left hemisphere using the Klingler method and provide high-quality stereoscopic views with the aim to help teach medical students or surgeons the three-dimensional anatomy of the brain. METHODS: Three left hemispheres were extracted and prepared. Then, according to the Klingler method, dissections were carried out from the lateral aspect. Photographs were taken at each step and were modified to provide stereoscopic three-dimensional views. RESULTS: Gray and white structures were described: cortex, claustrum, putamen, pallidum, caudate nucleus, amygdala; U-fibers, external and internal capsules, superior longitudinal fasciculus, frontal aslant fasciculus, uncinate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, corticospinal fasciculus, corona radiata, anterior commissure, and optic radiations. CONCLUSION: This educational stereoscopic presentation of an expert dissection of brain white fibers and basal ganglia would be of value for theoretical or hands-on teaching of brain anatomy; labeling and stereoscopy could, moreover, improve the teaching, understanding, and memorizing of brain anatomy. In addition, this could be also used for the creation of a mental map by neurosurgeons for the preoperative planning of brain tumor surgery.

Small fibre pathology, small fibre symptoms and pain in fibromyalgia syndrome.

A proportion of people with fibromyalgia demonstrate small fibre pathology (SFP). However, it is unclear how SFP directly relates to pain phenomenology. Thirty-three individuals with FMS and ten healthy volunteers underwent assessment of SFP and sensory phenotyping using corneal confocal microscopy, validated questionnaires and quantitative sensory testing (QST). Corneal nerve fibre length was used to stratify participants with fibromyalgia into with SFP [SFP+] and without SFP [SFP-]. SFP was detected in 50% of the fibromyalgia cohort. Current pain score and QST parameters did not differ between SFP+ and SFP-. Mechanical pain sensitivity (MPS) demonstrated a significant gain-of-function in the SFP- cohort compared to healthy-volunteers (p = 0.014, F = 4.806, η2 = 0.22). Further stratification revealed a cohort without structural SFP but with symptoms compatible with small fibre neuropathy symptoms and a significant gain in function in MPS (p = 0.020 Chi-square). Additionally, this cohort reported higher scores for both depression (p = 0.039, H = 8.483, η2 = 0.312) and anxiety (p = 0.022, F = 3.587, η2 = 0.293). This study confirms that SFP is present in a proportion of people with fibromyalgia. We also show that in a proportion of people with fibromyalgia, small fibre neuropathy symptoms are present in the absence of structural SFP. Greater mechanical pain sensitivity, depression and anxiety are seen in these individuals.

Acquired myelinated retinal nerve fiber layer in a child with neurofibromatosis 1-related optic pathway glioma.

Myelinated retinal nerve fiber layer (RNFL) is a rare structural anomaly that occurs from abnormal myelination extending anterior to the lamina cribrosa. Clinically, myelinated RNFL is characterized as a gray-white lesion with feathered, well-demarcated borders obscuring the retinal vasculature. Myelinated RNFL is typically congenital, benign, and asymptomatic. It is most commonly noted as an incidental finding on ophthalmic examination. However, cases of acquired myelinated RNFL have been reported. We report the case of a patient with neurofibromatosis type 1 and optic pathway glioma with unilateral acquired myelinated RNFL.

Absence of functional deficits in rats following systemic administration of an AAV9 vector despite moderate peripheral nerve and dorsal root ganglia findings: A clinically silent peripheral neuropathy.

Adeno-associated virus (AAV)-based vectors are commonly used for delivering transgenes in gene therapy studies, but they are also known to cause dorsal root ganglia (DRG) and peripheral nerve toxicities in animals. However, the functional implications of these pathologic findings and their time course remain unclear. At 2, 4, 6, and 8 weeks following a single dose of an AAV9 vector carrying human frataxin transgene in rats, non-standard functional assessments, including von Frey filament, electrophysiology, and Rotarod tests, were conducted longitudinally to measure allodynia, nerve conduction velocity, and coordination, respectively. Additionally, DRGs, peripheral nerves, brain and spinal cord were evaluated histologically and circulating neurofilament light chain (NfL) was quantified at 1, 2, 4, and 8 weeks, respectively. At 2 and 4 weeks after dosing, minimal-to-moderate nerve fiber degeneration and neuronal degeneration were observed in the DRGs in some of the AAV9 vector-dosed animals. At 8 weeks, nerve fiber degeneration was observed in DRGs, with or without neuronal degeneration, and in sciatic nerves of all AAV9 vector-dosed animals. NfL values were higher in AAV9 vector-treated animals at weeks 4 and 8 compared with controls. However, there were no significant differences in the three functional endpoints evaluated between the AAV9 vector- and vehicle-dosed animals, or in a longitudinal comparison between baseline (predose), 4, and 8 week values in the AAV9 vector-dose animals. These findings demonstrate that there is no detectable functional consequence to the minimal-to-moderate neurodegeneration observed with our AAV9 vector treatment in rats, suggesting a functional tolerance or reserve for loss of DRG neurons after systemic administration of AAV9 vector.

Cutaneous nerve biopsy in patients with symptoms of small fiber neuropathy: a retrospective study.

OBJECTIVES: We aimed to investigate to what extent small fiber tests were abnormal in an unselected retrospective patient material with symptoms suggesting that small fiber neuropathy (SFN) could be present, and to evaluate possible gender differences. METHODS: Nerve conduction studies (NCS), skin biopsy for determination of intraepidermal nerve fiber density (IENFD) and quantitative sensory testing (QST) were performed. Z-scores were calculated from reference materials to adjust for the effects of age and gender/height. RESULTS: Two hundred and three patients, 148 females and 55 males had normal NCS and were considered to have possible SFN. 45.3 % had reduced IENFD, 43.2 % of the females and 50.9 % of the males. Mean IENFD was 7.3 ± 2.6 fibers/mm in females and 6.1 ± 2.3 in males (p<0.001), but the difference was not significant when adopting Z-scores. Comparison of gender differences between those with normal and abnormal IENFD were not significant when Z-scores were applied. QST was abnormal in 50 % of the patients (48.9 % in females and 52.9 % in males). In the low IENFD group 45 cases out of 90 (50 %) were recorded with abnormal QST. In those with normal IENFD 51 of 102 (50 %) showed abnormal QST. CONCLUSIONS: Less than half of these patients had reduced IENFD, and 50 % had abnormal QST. There were no gender differences. A more strict selection of patients might have increased the sensitivity, but functional changes in unmyelinated nerve fibers are also known to occur with normal IENFD. Approval to collect data was given by the Norwegian data protection authority at University Hospital of North Norway (Project no. 02028).

Tuberculum meningioma with recovery of glaucoma-like visual field defects after chiasmal decompression: a case report.

BACKGROUND: To report a case of tuberculum meningioma with recovery of glaucoma-like visual field defects after chiasmal decompression. CASE PRESENTATION: A 39-year-old woman presenting with headache was found to have bilateral arcuate retinal nerve fiber layer (RNFL) thinning on optical coherence tomography (OCT) with a corresponding arcuate scotomas consistent with glaucomatous change. However a suprasellar tumor compressing the anterior chiasm from below was found on magnetic resonance imaging of the brain. After resection of the mass, which was diagnosed as meningothelial meningioma by the pathological examination, the glaucoma-like visual field defects resolved despite the RNFL thinning on the OCT showing no improvement. CONCLUSIONS: Chiasmal compression may mimic glaucoma and produce arcuate scotoma rather than temporal visual field loss. There is a possibility that the development of chiasmal compression somehow converted preperimetric glaucoma into a more advanced form accompanied by visual field defects and that the glaucoma reverted to the preperimetric state after chiasmal decompression.

THE EFFECT OF INTERNAL LIMITING MEMBRANE PEELING ON THE INNER RETINAL LAYERS IN PATIENTS WITHOUT MACULAR PATHOLOGIC CONDITION.

BACKGROUND: To examine the effect of internal limiting membrane peeling on the inner retinal layers in patients without macular pathological condition. METHODS: A prospective nonrandomized trial of patients undergoing pars plana vitrectomy with internal limiting membrane peeling for pathologic condition outside the macula was performed. Optical coherence tomography including macular ganglion cell layer, inner plexiform layer, and peripapillary retinal nerve fiber layer imaging was performed before surgery, 1, 3, and 6 months postoperatively, and at the end of follow-up (ranges between 4 and 17 months). Patients with any macular pathological condition on optical coherence tomography before surgery were excluded. The main outcome measure was change in thickness of the ganglion cell layer and inner plexiform layer. RESULTS: Ten patients who underwent pars plana vitrectomy with internal limiting membrane peeling for macula-on retinal detachment were included in the analysis. The mean age was 55 years, and the mean follow up was 10.8 months. All patients completed at least two postoperative follow-up visits that included an optical coherence tomography as per the protocol (range 2-6 months). There was an immediate reduction in the global (G), inferotemporal, superotemporal, and superior (S) ganglion cell layer thickness at the first follow up as compared with the preoperative state ( P = 0.028, P = 0.027, P = 0.026, and P = 0.027 respectively). From the first follow-up visit onward until the final follow-up, the thinning persisted, although there was no further statistically significant thinning. CONCLUSION: Peeling of the internal limiting membrane causes significant ganglion cell layer thinning in maculae without pathologic condition before surgery. At up to 17 months of follow-up, this effect seems to be immediate and nonprogressive.

Studying serum neurofilament light chain levels as a potential new biomarker for small fiber neuropathy.

BACKGROUND AND PURPOSE: Diagnosing small fiber neuropathies can be challenging. To address this issue, whether serum neurofilament light chain (sNfL) could serve as a potential biomarker of damage to epidermal Aδ- and C-fibers was tested. METHODS: Serum NfL levels were assessed in 30 patients diagnosed with small fiber neuropathy and were compared to a control group of 19 healthy individuals. Electrophysiological studies, quantitative sensory testing and quantification of intraepidermal nerve fiber density after skin biopsy were performed in both the proximal and distal leg. RESULTS: Serum NfL levels were not increased in patients with small fiber neuropathy compared to healthy controls (9.1 ± 3.9 and 9.4 ± 3.8, p = 0.83) and did not correlate with intraepidermal nerve fiber density at the lateral calf or lateral thigh or with other parameters of small fiber impairment. CONCLUSION: Serum NfL levels cannot serve as a biomarker for small fiber damage.

The Relationship Between Choroidal Abnormalities and Visual Outcomes in Pediatric Patients With NF1-Associated Optic Pathway Gliomas.

BACKGROUND: Choroidal abnormalities (CAs) visualized on near-infrared reflectance (NIR) imaging are a new diagnostic criterion for neurofibromatosis type 1 (NF1), but the association between the presence of CAs and visual function remains unknown. This study evaluated the relationship between visual acuity (VA) with the presence, number, or total area of CAs visualized by NIR in children with NF1-associated optic pathway gliomas (NF1-OPGs). METHODS: Patients (<18 years) enrolled in a prospective longitudinal study of children with NF1-associated OPGs from 3 institutions were eligible if they had optical coherence tomography (OCT) of the macula (Heidelberg Spectralis) with ≥1 year of follow-up. The central 30° NIR images were reviewed by 2 neuro-ophthalmologists who manually calculated the number and total area of CAs. VA (logMAR) was measured using a standardized protocol. Cross-sectional associations of presence, number, and total area of CAs with VA, retinal nerve fiber layer thickness (RNFL), and ganglion cell-inner plexiform layer thickness were evaluated at the first and most recent visits using regression models. Intereye correlation was accounted for using generalized estimating equations. RESULTS: Eighty-two eyes of 41 children (56% female) were included. The mean ± SD age at the first OCT was 10.1 ± 3.3 years, with a mean follow-up of 20.4 ± 7.2 months. At study entry, CAs were present in 46% of eyes with a mean number of 2.1 ± 1.7 and a mean total area of 2.0 ± 1.7 mm 2 per eye. At the most recent follow-up, CAs were present in 48% of eyes with a mean number of 2.2 ± 1.8 lesions and a mean total area of 2.3 ± 2.1 mm 2 per eye. Neither VA nor OCT parameters at first and follow-up visits were associated with the presence, number, or total area of CAs (all P > 0.05). CONCLUSIONS: CAs are prevalent but not ubiquitous, in children with NF1-OPGs. Although CAs are a diagnostic criterion for NF1, their presence and size do not appear to be associated with visual function.

Clinical Characteristics of Microcystic Macular Edema in Chronic Primary Angle-Closure Glaucoma and Primary Open-Angle Glaucoma Patients.

INTRODUCTION: This study investigated the clinical characteristics of and risk factors for microcystic macular edema (MME) in patients with chronic primary angle-closure glaucoma (CPACG) and primary open-angle glaucoma (POAG). METHODS: This retrospective observational study included 1,588 eyes from 926 glaucoma inpatients and analyzed the patients' basic demographic information, visual field parameters, macular scans, and peripapillary retinal nerve fiber layer thickness. RESULTS: Our findings were that the incidence rate of MME was 3.97% (34/857) in CPACG and 5.88% (43/731) in POAG. MME was predominantly diagnosed at an advanced stage in CPACG (almost 100%) compared to POAG (93.02%). MME was most frequently involved in the inferior (83.12%) quadrant of the peri-macular region in both CPACG and POAG. Risk factors for MME occurrence in CPACG and POAG included lower visual field mean deviation (OR = 1.14, 95%: CI 1.05-1.24, p = 0.003; OR = 1.14, 95% CI: 1.06-1.21, p < 0.001) and younger age (OR = 0.92, 95% CI: 0.88-0.96, p < 0.001; OR = 0.96, 95% CI: 0.93-0.99, p = 0.003), while female sex (OR = 0.30, 95% CI: 0.11-0.84, p = 0.022) reduced the MME occurrence in POAG. CONCLUSION: MME could develop in both CPACG and POAG patients, occurring earlier in POAG. The inferior peri-macular region is commonly affected. Younger age and poorer visual field are risk factors for MME in glaucoma patients.

The Relationship between Lumbar Puncture Opening Pressure and Retinal Nerve Fiber Layer Thickness in the Diagnosis of Idiopathic Intracranial Hypertension: Is a Lumbar Puncture Always Necessary?

OBJECTIVES: Idiopathic intracranial hypertension (IIH), is characterized by elevated intracranial pressure (ICP) without an identified cause. Today, lumbar puncture (LP) is the most common method used for diagnosis by measuring cerebrospinal fluid (CSF) pressure to reflect intracranial pressure. This invasive examination has significant disadvantages, such as complications and negative experiences for patients. Therefore, noninvasive methods for ICP measurement are desired. Optical coherence tomography (OCT) is widely used for the diagnosis and follow-up of IIH patients as it reflects papilledema. The aim of this study is to investigate the relationship between CSF pressure and OCT parameters and the ability of OCT in the diagnostic approach. METHODS: In our study, patients who were followed up with a diagnosis of IIH with complete neuro-ophthalmological examinations, including visual acuity (VA), visual field, and OCT imaging within 24 hours before lumbar puncture, were retrospectively evaluated. CSF pressure, visual acuity LogMAR, mean deviation of visual fields, retinal nerve fiber layer (RNFL) thickness measured by OCT, and treatment protocols were obtained from our hospital data system. RESULTS: A total of 42 eyes of 21 patients were enrolled in the study. A statistically significant positive and moderate correlation was found between CSF pressure values and average RNFL thickness ( r =0.507; P =0.001). The same relationship was demonstrated in all 4 quadrants: inferior, superior, nasal, and temporal. CONCLUSIONS: Increased peripapillary RNFL thickness in optic nerve head OCT may be correlated with increased ICP in IIH patients. A larger number of patients are needed to better understand the correlation between OCT parameters and CSF pressure in patients with IIH.

Peripapillary retinal nerve fiber layer thickness as a diagnostic tool for pseudophakic cystoid macular edema.

PURPOSE: To investigate the effects of pseudophakic cystoid macular edema (PCME) on retinal nerve fiber layer (RNFL) thickness before and after treatment using optical coherence tomography (OCT). METHODS: A retrospective, observational study of consecutive patients diagnosed with PCME after cataract surgery. Patients underwent macular and RNFL OCT imaging at time of diagnosis and during follow up. OCT was performed for both the study eye and the contralateral healthy eye which served as control. All patients were followed for a period of at least 6 months. RESULTS: Overall, 40 eyes of 40 patients with a mean age of 71.1 ± 8.1 years of which 45% (n = 18) were of male gender were included in this study. At presentation, the central thickness in the PCME eye was significantly higher than in the contralateral eye (515.7 ± 127.9µm versus 238.1 ± 41.8µm, p < 0.001). Similarly, all macular measurements were significantly higher in the PCME eye compared to the contralateral eye (p < 0.001 for all). In terms of RNFL measurements, the PCME eyes had greater global (p < 0.001), superonasal (p = 0.001) and superotemporal (p = 0.005) thickness values. PCME eyes demonstrated a significant decrease in thickness for all macular and RNFL parameters following resolution of CME (p < 0.05 for all). CONCLUSIONS: PCME patients presents with greater global, superotemporal and superonasal RNFL thickness in comparison to the other healthy eye. After resolution of PCME, there is significant thinning of RNFL. Peripapillary RNFL thickness may serve as an additional parameter for diagnosis and follow-up of PCME.

Impact of Age on the Characteristics of Corneal Nerves and Corneal Epithelial Cells in Healthy Adults.

PURPOSE: The aim of this study was to investigate age-related changes in corneal nerves and corneal epithelial cell parameters and to establish age-adjusted reference values. METHODS: A total of 7025 corneal nerve images and 4215 corneal epithelial images obtained using in vivo confocal microscopy from 281 eyes of 143 healthy participants were included. Seven corneal nerve parameters and 3 corneal epithelial cell parameters were quantified using 2 automatic analytic software and analyzed across 6 age groups ranging from 21 to 80 years. RESULTS: There was a declining trend in all 7 nerve parameters with advancing age. In particular, corneal nerve fiber length and corneal nerve fiber density demonstrated a significant decrease in subjects aged 65 years or older compared with subjects younger than 65 years (10.8 ± 2.6 mm/mm 2 vs. 9.9 ± 2.0 mm/mm 2 , P = 0.011 in corneal nerve fiber length; 15.8 ± 5.2 fibers/mm 2 vs. 14.4 ± 4.3 fibers/mm 2 , P = 0.046 in corneal nerve fiber density), whereas corneal nerve fractal dimension demonstrated a borderline significant decrease ( P = 0.057). Similarly, there was a general declining trend in all epithelial cell parameters with advancing age. Corneal epithelial cell circularity was significantly lower in subjects aged 65 years and older as compared to subjects younger than 65 years (0.722 ± 0.021 µm 2 vs. 0.714 ± 0.021 µm 2 ; P = 0.011). CONCLUSIONS: Advancing age results in reduced corneal nerve metrics and alteration of corneal cell morphology. Aging effects should be considered when evaluating patients with corneal neuropathy.

Correlation between a commercial electrophysiological test of sudomotor function and intraepidermal nerve fiber density in hereditary transthyretin amyloidosis.

INTRODUCTION/AIMS: In the early stage, hereditary transthyretin (ATTRv) amyloidosis predominantly affects small nerve fibers, resulting in autonomic dysfunction and impaired sensation of pain and temperature. Evaluation of small fiber neuropathy (SFN) is therefore important for early diagnosis and treatment of ATTRv amyloidosis. Herein, we aimed to investigate the accuracy of a quick and non-invasive commercial sudomotor function test (SFT) for the assessment of SFN in ATTRv amyloidosis. METHODS: We performed the SFT in 39 Japanese adults with ATTRv amyloidosis, and we analyzed the correlations between electrochemical skin conductance (ESC) values obtained via the SFT and the parameters of other neuropathy assessment methods. RESULTS: ESC in the feet demonstrated significant, moderate correlations with intraepidermal nerve fiber density (IENFD) results (Spearman's rank correlation coefficient [rs ], 0.58; p < .002) and other neuropathy assessment methods including the sensory nerve action potential amplitude in the nerve conduction studies (rs , 0.52; p < .001), the Neuropathy Impairment Score (rs , -0.45; p < .01), the heat-pain detection threshold (rs , -0.62; p < .0001), and the autonomic section of the Kumamoto ATTRv clinical score (rs , -0.53; p < .0001). DISCUSSION: In this study, we found that ESC values in the feet via the SFT demonstrated significant, moderate correlations with IENFD and other SFN assessment methods in patients with ATTRv amyloidosis, suggesting that the SFT appears to be an appropriate method for assessment of SFN in this disease.