Measurement of Optic Nerve Sheath Diameter: Differences between Methods? A Pilot Study.

BACKGROUND: Quantification of the optic nerve sheath diameter is a promising approach for the detection of elevated intracranial pressure. The comparability of current methods is unclear. The objective of this study was to assess the relationship between optic nerve sheath diameter as measured with computed tomography, magnetic resonance tomography and ultrasound in patients without known optic nerve disease or increased intracranial pressure. PATIENTS AND METHODS: 15 patients (60.8 [years]±16.73 SD; 7 female) with paranasal sinus pathology in whom computed tomography and magnetic resonance imaging were performed underwent optic nerve sheath diameter measurements by ultrasound, as well as an ophthalmological examination. Ultrasound-, computed tomography- and magnetic resonance imaging-derived maximal optic nerve sheath diameter values 3 mm behind the globe were compared. RESULTS: Optic nerve sheath diameter measured (n=30) by ultrasound (mean 6.2 [mm]±0.84 SD) was significantly (p<0.01) higher than optic nerve sheath diameter in computed tomography (5.2±1.11) or magnetic resonance imaging (5.3±1.14). There was no significant (p=0.24) difference between optic nerve sheath diameter measured in computed tomography and magnetic resonance tomography. CONCLUSIONS: The comparability of optic nerve sheath diameter measurements in patients without known optic nerve disease and assumed normal intracranial pressure appears to be given between computed tomography and magnetic resonance tomography, while comparability between ultrasound and computed tomography or magnetic resonance tomography seems to be less reliable.

Cerebrospinal fluid dynamics between the intracranial and the subarachnoid space of the optic nerve. Is it always bidirectional?

CSF is thought to flow continuously from the site of production in the ventricles into interconnected spaces; i.e. cisterns and subarachnoid spaces (SASs). Since the SAS of the optic nerve is defined by a cul-de-sac anatomy, it is not evident how local CSF might recycle from that region to the general SAS. The concept of free communication of CSF has recently been challenged by the description of a concentration gradient of beta-trace protein, a lipocalin-like prostaglandin d-synthase (L-PGDS), between the spinal CSF and that in the SAS of the optic nerve, indicating diminished local clearance or local overproduction of L-PGDS here. In fact, computed cisternography with a contrast agent in three patients with idiopathic intracranial hypertension and asymmetric papilloedema demonstrate a lack of contrast-loaded CSF in the SAS of the optic nerve despite it being present in the intracranial SAS, thus suggesting compartmentation of the SAS of the optic nerve. The concept of an optic nerve compartment syndrome is further supported by a concentration gradient of brain-derived L-PGDS between the spinal CSF and the CSF from the optic nerve SAS in the same patients.

Normal tension glaucoma: review of current understanding and mechanisms of the pathogenesis.

Normal tension glaucoma (NTG) is an exception in the "glaucoma family" where the major risk factor, increased intraocular pressure, is missing. If not increased intraocular pressure, then what other causes can then lead to glaucomatous optic disc change and visual field loss in NTG? Several possibilities will be discussed. Among them a higher sensitivity to normal pressure, vascular dysregulation, an abnormally high translaminar pressure gradient and a neurodegenerative process due to impaired cerebrospinal fluid dynamics in the optic nerve sheath compartment. There are many excellent review papers published on normal tension glaucoma (NTG). The aim of this paper is therefore not to add another extensive review on NTG but rather to focus on and to discuss some possible mechanisms that are thought to be involved in the pathophysiology of NTG and to discuss the stronger and weaker aspects of each concept. The fact that several concepts exist suggests that NTG is still not very well understood and that no single mechanism on its own might adequately explain NTG.

The optic nerve: a new window into cerebrospinal fluid composition?

Cerebrospinal fluid (CSF) pressure and composition are generally thought to be homogeneous within small limits throughout all CSF compartments. CSF sampled during lumbar puncture therefore should be representative for all CSF compartments. On the basis of clinical findings, histology and biochemical markers, we present for the first time strong evidence that the subarachnoid spaces (SAS) of the optic nerve (ON) can become separated from other CSF compartments in certain ON disorders, thus leading to an ON sheath compartment syndrome. This may result in an abnormal concentration gradient of CSF molecular markers determined in locally sampled CSF compared with CSF taken during lumbar puncture.

Optic nerve compartment syndrome in a patient with optic nerve sheath meningioma.

PURPOSE: To report a patient with optic nerve (ON) sheath meningioma, unilateral optic disc swelling, and inhomogeneous cerebrospinal fluid (CSF) composition between lumbar CSF and CSF from the subarachnoid space (SAS) of the affected ON. METHODS: A 39-year-old woman presented with unilateral optic disc swelling and slight deterioration of visual function in the left eye. Extensive laboratory workup and magnetic resonance imaging (MRI) of the brain and orbits were performed. As radiotherapy was refused by the patient, ON sheath fenestration (ONSF) was offered and performed in order to stop deterioration. CSF from the SAS of the ON was sampled. RESULTS: Laboratory workup was within normal limits. MRI of the left orbit demonstrated enhancement of the dura in the precanalicular portion of the ON and distension of the SAS, most prominent in the bulbar portion of the ON. On lumbar puncture the opening pressure measured 19 (cm H2O). Compared to the lumbar CSF the CSF of the affected ON SAS showed markedly elevated measurements for albumin, IgG, and beta-trace protein. Visual function remained stable over a follow-up time of 18 months. CONCLUSIONS: Composition of CSF is considered to be homogenous throughout all CSF spaces. In this patient the authors found a marked concentration-gradient of albumin, IgG, and beta-trace protein between the CSF in the spinal canal and the CSF in the SAS of the affected ON. Based on the radiologic features of the left ON and the dissociated beta-trace protein concentrations in the CSF of the SAS of the ON and the lumbar CSF, the diagnosis of an ON sheath compartment syndrome due to an ON sheath meningioma was made.

Relationship between the optic nerve sheath diameter and lumbar cerebrospinal fluid pressure in patients with normal tension glaucoma.

PurposeTo investigate on the relationship between the optic nerve sheath diameter (ONSD) and the lumbar cerebrospinal fluid pressure (CSF-p) in Caucasian patients with normal tension glaucoma (NTG).Patients and methodsRetrospective analysis of medical records of patients with open-angle glaucoma in the period from 2005 to 2015 from the Ophthalmology Department, Cantonal Hospital Aarau, Switzerland was performed. A total of 38 patients (mean age 68.6±11.3 years, 21 females and 17 males) fulfilled the diagnostic criteria of NTG and underwent computed tomography (CT) of the orbit and lumbar puncture (LP). In total, 38 age- and gender-matched Caucasian subjects (mean age: 68.9±10.9 years) without known ON diseases served as controls for ONSD measurements. ONSDs were measured at a distance of 3 mm from the posterior globe and lumbar CSF-p was related to the measurements. Statistical analysis was performed by using the independent two-tailed t-test and the non-parametric Spearman's correlation test.ResultsThe mean ONSD in NTGs measured 6.4±0.9 mm and in controls 5.4±0.6 mm. The difference between NTGs and controls showed statistical significance (t-test: P<0.000). The mean CSF-p in NTG was 11.6±3.7 mm Hg. There was no statistical significant correlation between ONSD and CSF-p (Spearman's correlation coefficient ρ=0.06, P=0.72).ConclusionsThis study demonstrates enlarged ONSDs and normal lumbar CSF-p in 38 Caucasian NTG patients. As enlarged ONSDs generally are associated with increased intracranial CSF-p, these results can be explained by a disturbed communication of CSF-p between the intracranial and intraorbital subarachnoid spaces.

When is isolated inferior oblique muscle surgery an appropriate treatment for superior oblique palsy?

PURPOSE: To evaluate the efficacy of isolated inferior oblique muscle weakening in the treatment of superior oblique palsy. METHODS: Forty-seven patients with superior oblique palsy underwent either single-muscle surgery (anteriorization or recession of the inferior oblique muscle) or two-muscle surgery (anteriorization of the inferior oblique muscle combined with recession of the contralateral inferior rectus muscle according to the amount of vertical deviation). In a retrospective noncomparative study the objective surgical effect was calculated as the difference between the deviation at the day before surgery and the deviations 6 weeks and at least 1 year after surgery. Pre- and postoperative sensorimotor status and subjective outcome were evaluated. RESULTS: In patients who underwent isolated inferior oblique muscle surgery the mean preoperative vertical deviation decreased from 15+/-9 (distance)/16+/-10 (near) prism diopters (PD) (anteriorization) and 7+/-5 (distance)/9+/-8 (near) PD (recession) to 4+/-4 (distance)/4+/-6 (near) PD (anteriorization) and 2+/-2 (distance)/2+/-3 (near) PD (recession) at the 1-year follow-up. In patients who underwent two-muscle surgery the mean vertical deviation decreased from 20+/-11 (distance)/21+/-10 (near) PD preoperatively and 6+/-7 (distance)/6+/-6 (near) PD at 1-year follow-up. Subjective assessment showed excellent scores among the patients treated with single-muscle surgery and slightly lower but also favorable scores among the patients treated with combined techniques. A direct comparison of the different outcome scores was not possible because of the more difficult initial situation in patients who underwent combined surgery. CONCLUSIONS: Isolated inferior oblique muscle weakening is an effective treatment option for superior oblique palsy up to 15 PD of vertical deviation in primary position. Two-muscle surgery should be reserved for patients with larger vertical deviations.

Natural history of radiation-induced brachial plexopathy compared with surgically treated patients.

Twelve patients who developed radiation-induced brachial plexopathy (RIBP) after receiving radiation therapy for breast carcinoma (7 patients) or Hodgkin's lymphoma (5 patients) were followed for 12 or more years, with a mean follow-up time of 20 years. Tingling and numbness of the fingers as well as weakness of the hand or arm were the most prominent presenting symptoms of RIBP. Whereas pain in most patients evolved only later in the course, it became a predominant feature in only 2. In 8 of the 12 patients, the plexopathy was surgically treated, either by neurolysis only or by neurolysis plus omental grafting in order to stop progression or paresis and/or pain. In 8 patients, including 6 of the operated group, there was slow and steady progression of RIBP over time, with the final outcome being almost complete paralysis of the arm (2 patients) or severe sensorimotor paresis rendering the hand useless (6 patients). In only 4 patients, including 2 of the non-operated group, was there absence of progression and stabilization of the paresis with only slight functional loss of the affected arm in 3 patients and severe palsy in 1. None of the 12 patients had any clear long-lasting improvement of their sensorimotor impairment. It is concluded from this study that RIBP, irrespective of surgery (neurolysis and/or omentum transplant), left two-thirds of the patients with severe or total paresis of the arm. However, the almost complete relief of severe pain (6 of 8 patients), both immediately and in follow-up patients treated with neurolysis and/or omental transplant, indicates that surgical treatment has a beneficial effect on pain relief.

Unilateral papilledema caused by a fronto-temporo-parietal arachnoid cyst.

PURPOSE: To report a case of unilateral papilledema caused by an arachnoid cyst. METHODS: Interventional case report. RESULTS: A 36-year-old woman presented with unilateral papilledema in the left eye. Magnetic resonance imaging (MRI) of the brain demonstrated a large fronto-temporo-parietal arachnoid cyst in the left hemisphere. The papilledema resolved after placement of a cysto-peritoneal shunt that drained the cerebrospinal fluid directly from the arachnoid cyst into the peritoneum. CONCLUSION: Papilledema caused by increased intracranial pressure is usually bilateral; unilateral papilledema is possible under special anatomical circumstances.

Acute asymmetric upper nasal quandrantanopsia caused by a chiasmal colloid cyst in a patient with multiple sclerosis and bilateral retrobulbar neuritis.

PURPOSE: To report a patient with multiple sclerosis and a history of sequential bilateral retrobulbar neuritis, who developed new onset of highly asymmetric upper quadrantanopsia. DESIGN: Interventional case report. METHOD: A 36-year-old woman with multiple sclerosis and bilateral retrobulbar neuritis developed an acute asymmetric upper nasal quadrantanopsia. RESULTS: Magnetic resonance imaging of the brain revealed a cyst that caused chiasmal compression and bilateral visual field defects. CONCLUSION: New onset of bilateral visual field defects in a patient with diagnosed multiple sclerosis is likely to be caused by a new attack of the demyelinating disease. In this case, a newly diagnosed chiasmal colloid cyst was the cause of visual field defects.

Architecture of arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve: anatomy and clinical considerations.

AIMS: To describe the anatomy and the arrangement of the arachnoid trabeculae, pillars, and septa in the subarachnoid space of the human optic nerve and to consider their possible clinical relevance for cerebrospinal fluid dynamics and fluid pressure in the subarachnoid space of the human optic nerve. METHODS: Postmortem study with a total of 12 optic nerves harvested from nine subjects without ocular disease. All optic nerves used in this study were obtained no later than 7 hours after death, following qualified consent for necropsy. The study was performed with transmission (TEM) and scanning electron microscopy (SEM). RESULTS: The subarachnoid space of the human optic nerve contains a variety of trabeculae, septa, and stout pillars that are arranged between the arachnoid and the pia layers of the meninges of the nerve. They display a considerable numeric and structural variability depending on their location within the different portions of the optic nerve. In the bulbar segment (ampulla), adjacent to the globe, a dense and highly ramified meshwork of delicate trabeculae is arranged in a reticular fashion. Between the arachnoid trabeculae, interconnecting velum-like processes are observed. In the mid-orbital segment of the orbital portion, the subarachnoid space is subdivided, and can appear even loosely chambered by broad trabeculae and velum-like septa at some locations. In the intracanalicular segment additionally, few stout pillars and single round trabeculae are observed. CONCLUSION: The subarachnoid space of the human optic nerve is not a homogeneous and anatomically empty chamber filled with cerebrospinal fluid, but it contains a complex system of arachnoid trabeculae and septa that divide the subarachnoid space. The trabeculae, septa, and pillars, as well as their arrangement described in this study, may have a role in the cerebrospinal fluid dynamics between the subarachnoid space of the optic nerve and the chiasmal cistern and may contribute to the understanding of the pathophysiology of asymmetric and unilateral papilloedema. All the structures described are of such delicate character that they can not even be visualised with high resolution magnetic resonance imaging (MRI).

Corneal penetration of diclofenac from a fixed combination of diclofenac-gentamicin eyedrops.

PURPOSE: To establish the corneal penetration of diclofenac in the presence of gentamicin in patients having cataract surgery. SETTING: Kantonsspital Augenklinik, Aarau, and Hôpital Jules Gonin, Lausanne, Switzerland. METHODS: Eligible patients having cataract surgery (39 women, 30 men) were treated with 4 drops of diclofenac 0.1%-gentamicin 0.3% (Voltamicin) instilled at 20 minute intervals. Paracentesis was performed 15, 30, or 60 minutes after the last instillation, and a sample of aqueous humor was collected for analysis of diclofenac by high-performance liquid chromatography. Blood samples of some patients were obtained before surgery for analysis. RESULTS: Mean diclofenac levels (+/- SD) in the aqueous humor 15, 30, and 60 minutes after the last instillation were 72 +/- 84, 108 +/- 87, and 201 +/- 116 ng/mL (= 682 nMol/L), respectively. Diclofenac remained below the limit of detection (5 ng/mL) in all samples of blood serum. In general, local tolerance was good; no side effects were reported. Comparison of the data with published results of topically instilled diclofenac 0.1% suggests that the concentration of diclofenac in the aqueous humor achieved with 4 instillations of the combination product is similar to that achieved with 8 instillations of diclofenac 0.1% (Voltaren Ophtha) alone. CONCLUSIONS: Drug levels of diclofenac in the aqueous humor well above IC-50 for cyclo-oxygenase were achieved with the regimen applied. No inhibitory effect by the gentamicin or vehicle was observed. Comparison of these data with published results of Voltaren Ophtha implies a 2-fold better penetration of diclofenac with the diclofenac-gentamicin combination.

Comparison of the anti-inflammatory potency and local tolerance of diclofenac and indomethacin eye drops in the postoperative management of patients undergoing ECCE with PCL.

Prostaglandins have been shown to mediate various manifestations of ocular inflammation. Diclofenac and indomethacin are thought to inhibit cyclooxygenase, an enzyme necessary for prostaglandin biosynthesis. The anti-inflammatory effect and subjective tolerance of topical diclofenac 0.1% and indomethacin 0.1% were examined in the postoperative treatment of 64 patients undergoing extracapsular cataract surgery with IOL implantation in a prospective, comparative, single masked study. Patients with preexisting ocular disease or whose intraoperative course was complicated were excluded from the study. Ophthalmologic examinations were performed preoperatively and at days: 1, 4-6, and 28-30 post surgery. Tolerance was assessed by subjective patient evaluation. There was no significant difference (p < 0.05) in postoperative inflammation among the two treatment groups. There was a trend for more severe corneal edema on day 4-6 in the indomethacin group. Diclofenac was slightly better tolerated.

Bilateral non-arteritic anterior ischemic optic neuropathy in a patient with autoimmune thrombocytopenia.

PURPOSE: To describe a patient with bilateral non-arteritic anterior ischemic optic neuropathy (NAION) and idiopathic autoimmune thrombocytopenia (ITP) with an extremely low platelet count. METHOD: Case report. RESULTS: Remarkably good recovery of visual acuity. CONCLUSIONS: Bilateral non-arteritic anterior ischemic optic neuropathy can develop in the presence of a very low platelet count.

[Vision disorders in normal eye status]. / Sehstörungen bei normalem Augenstatus.

The origin of unusual visual phenomena is usually located in the brain or in the brainstem. They appear with normal ophthalmologic findings. Neurologic and ophthalmologic knowledge is needed for a localizing diagnosis and neuro-imaging is most often required. Selected cases of peripherally to centrally located lesions are presented.