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.

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.

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.

Early detection of Best's disease in childhood due to ineffective orthoptic treatment.

BACKGROUND: A meticulous fundoscopy is an essential examination before administering an orthoptic occlusion therapy (patching), even in cases with a "clear indication" for patching. In this case of an 8-year-old hyperopic boy the subsequent fundoscopy revealed a bilateral maculopathy that explained the stagnation of the increase of the monocular visual acuity (VA) in spite of a correctly applied patching. HISTORY AND SIGNS: The patient was a boy (8 years old) with a history of ineffective orthoptic treatment for 15 months due to hyperopia. Complete ophthalmological examination, optical coherence tomography (Cirrus HD-OCT, Zeiss, Germany) and electro-oculography (EOG) were performed. No "everyday" symptoms were found. Best corrected VA (hyperopic) on the right was 10 / 20, on the left 8 / 20. Binocular VA was 20 / 20. 15 out of 15 Ishihara plates were identified on both sides. Orthophoria has been seen. Perimetry revealed bilateral nasal-parafoveal microscotoma. Fundoscopy showed a confined and slightly prominent yellow spot on the temporal side of the fovea. OCT revealed a subfoveal accumulation of solid material in the RPE in both eyes. EOG showed normal findings in our case. THERAPY AND OUTCOME: There was no further deterioration of VA in a follow-up time of 12 months. CONCLUSIONS: Ineffective orthoptic treatment (patching) in amblyopic children should prompt the ophthalmologist to a meticulous fundoscopy, even if done so before patching, which is highly recommended. This young patient had no "everyday" visual symptoms. Because mainly the temporal fovea on both sides was affected, he showed normal binocular VA inspite of bilateral VA reduction. The authors think that this effect is due to biretinal summation (retinal filling in).

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.

Retrobulbar blood flow in idiopathic dilated episcleral veins and glaucoma.

BACKGROUND: Dilated episcleral veins may occur in the presence of orbital tumors, carotid cavernous sinus fistula and other orbital obstructive lesions. HISTORY AND SIGNS: A 39-year-old man had a history of a red left eye for two years. The visual acuity was 20/20, episcleral and conjunctival veins were dilated, and both the intraocular (24 mmHg) and episcleral venous (18 mmHg) pressures were increased. The canal of Schlemm was filled with blood, and glaucomatous damage was pronounced in the optic nerve head and the visual field of the left eye. The retrobulbar blood flow in the left eye was normal in the ophthalmic and central retinal arteries, but markedly decreased in the central retinal vein. There were no signs of fistula or shunts. The right eye was without any pathology. MR and catheter angiography of the head and orbit were both normal. THERAPY AND OUTCOME: Following trabeculectomy, the intraocular and episcleral venous pressures dropped to 9 mmHg and 8 mmHg, respectively, at 6 months follow-up. The episcleral and conjunctival venous congestion regressed, and the blood flow in the central retinal vein increased. CONCLUSION: The reason for the observed clinical picture (Radius-Maumenee syndrome) and haemodynamic improvement after reduction of the intraocular pressure is not clear. We outline a hypothesis involving an increase of the vascular resistance in the vortex veins and the superior ophthalmic vein with a shift in local blood volume and vascular pressure due to high intraocular pressure.

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.

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.

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.

Perioperative posterior ischemic optic neuropathy as a rare complication of blepharoplasty.

PURPOSE: To report a case of visual loss to light perception in the right eye after upper and lower eyelid blepharoplasty. DESIGN: Case report. METHOD: A 46-year-old man was referred 3 days after combined bilateral upper and lower lid blepharoplasty with visual acuity of light perception in the right eye. The fundus examination, fluorescein angiography and magnetic resonance imaging of the orbit were normal. Ocular motility was full in all directions of gaze. RESULT: The diagnosis of optic nerve damage was initially based on the relative afferent pupillary defect. The diagnosis of a perioperative posterior ischemic optic neuropathy was based on the Goldmann visual field examination and the subsequent optic atrophy. Central visual acuity, color vision as well as the visual field improved markedly within 3 months. CONCLUSION: Blindness is a rare but feared complication of blepharoplasty and is reported to occur in about 0.04% of cases. Although intraorbital hemorrhage is thought to be the leading cause for optic nerve damage in most of the patients with this devastating condition, we present a case with perioperative posterior ischemic optic neuropathy leading to visual loss after blepharoplasty. The mechanism leading to optic nerve damage in this patient may include compromised small arteries perfusing the optic disk due to direct mechanical compression and a probable vasoconstrictive activity of the anesthetic agent.

Multiple visual hallucinations and pseudohallucinations in one individual patient: when the world is turning upside down and the television keeps falling to the ground while dwarfs are parading on the ceiling.

We report on a patient who experienced visual hallucinations and pseudohallucinations comprising palinopsia, peduncular hallucinosis, and oblique vision. The most probable etiologies of these phenomena are discussed with respect to clinical presentation and findings on computed tomography and magnetic resonance imaging.

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).

[Secondary syphilis with ocular manifestations and oral ulceration]. / Sekundäre Lues mit okulärem Befall und Schleimhautulzera.

In this case-report we describe a patient who was first seen with a painless lesion of the chin. Despite treatment with antibiotics and steroids it didn't heal. Later on, painful ulcerations of the mouth, perianal itching lesions and a central skotoma appeared. In the hospital--course a syphilitic infection with multiple oral ulcerations and occular infestation was diagnosed. The lesion on the chin was interpreted as the primary chancre as a time--correlation of its appearance and the time of exposition could be documented. The epidemiology, the diagnostic measures are described. We outline the manifestations of syphilis and their change in our time and discuss therapeutic regimes.

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.