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Aims: To investigate the effects of artefacts on scanning laser polarimetry of the retinal nerve fibre layer., Methods: Six eyes of six normal volunteers and an artificial nerve fibre layer were examined using the nerve fibre analyser II. The retinal nerve fibre layer thickness (RNFLT) was measured in each of four 90 degree quadrants, superior (S), temporal (T), inferior (I), and nasal (N), at 1.5 disc diameters from the disc margin. Study 1: Measurement in normal eyes. The amount of maximum error in RNFLT measurements was investigated as follows: (1) the intensity setting of the laser beam was changed to be as weak as possible or to be as strong as possible; (2) the intentional offsets of the laser beam axis in relation to the pupil were made in four directions; (3) the eye was rotated by shifting the head 45 or 90 degrees; (4) the right eye was measured by moving it to the left eye position on the head rest. Study 2: Measurements on an artificial nerve fibre layer. The birefringence measurements were confirmed with a plastic disc, which has a radial arrangement of birefringence. The plastic disc with black paper was fixed at the right eye position or the left eye position on the head rest. The retardation of the laser beam by the plastic disc on the black paper was measured. The retardation of the plastic disc was checked by an automatic birefringence evaluation system (ABR-10A, Uniopt Co, Ltd, Shizuoka)., Results: Study 1: The effects of the rotated eye and the measurement of the opposite eye position were significant. The eyes rotated 90 degrees showed quite a different pattern in which the thicker and thinner locations of the RNFLT are switched. The nasal RNFLT of the baseline and the 90 degree rotated eye are 41.9 (SD 6.0) microm and 122.5 (11.2) microm, respectively (p<0.0001, Scheffe multiple comparison test). Study 2: The uniform retardation of the plastic disc was observed with the ABR-10A. The NFA detects the retardation of the plastic disc which the retardation map showed as a double humped pattern., Conclusions: Study 2 indicated that the amount of corneal compensation was not small. The cause of significant influences by the rotated eyes and right eyes measurement in left eye position were thought to be incorrect corneal compensation. To increase the diagnostic ability of SLP, an improved compensation of the cornea is thought to be important.

Orbital varices are a vascular hamartoma typified by a plexus of low pressure, low flow, thin walled and distensible vessels that intermingle with the normal orbital vessels. If freely communicating with the orbital circulation, engorgement of varices can occur by increasing venous pressure through the Valsalva manoeuvre, bending posture, coughing or straining and these, in turn, lead to the clinical characteristics of variable proptosis, intermittent pain, and orbital haemorrhage. Indications for surgical intervention include non-resolving episodes of thrombosis, severe disfiguring proptosis or displacement of the globe, and optic nerve compression.

Purpose This study examines the effect of the L-type calcium channel blocker verapamil on mechanical strain induced extracellular matrix genes in optic nerve head lamina cribrosa (LC) cells. Methods Changes in LC cell intracellular calcium[Ca2+]i following hypotonic cell membrane stretch were measured with the fluorescent probe fura-2/AM. Fluorescence intensity was measured, after labelling, by calcium (Ca2+) imaging confocal microscopy. Confluent human LC cell cultures were serum starved for 24 h prior to exposure to cyclical mechanical strain (1 Hz, 15%) for 24 h in the presence or absence of verapamil (10 mm).Transforming growth factor-β 1 (TGF-β1), collagen 6A3(COL6A3) and chondroitin sulfate proteoglycan 2(CSPG2) mRNA expression levels were assessed by quantitative RT-PCR. Results Hypotonic cell membrane stretch of LC cells from normal donors significantly increased [Ca2+]i ( p<0.05). Exposure to cyclical mechanical strain (15%strain) produced a statistically significant increase in the three matrix genes that were examined (TGF-β1,COL6A3 and CSPG2). This response in both cyclical and mechanical stretch was significantly reduced by pretreating LC cells with the L-type calcium channel blocker verapamil (p<0.05).Conclusions This study provides evidence of a novel mechanotransduction pathway linking mechanical strain, cation channel function and the induction of LC cell matrix gene transcription. This highlights the potential involvement of calcium influx in the activation of matrix remodelling responses in the optic nerve head and supports the rationale that calcium channel blockers may attenuate disease progression in glaucoma. [ABSTRACT FROM AUTHOR]

The lamina cribrosa (LC) is believed to be the site of injury to retinal ganglion cell axons in glaucoma. The ability to visualise this structure has the potential to help increase our understanding of the disease and be useful in the early detection of glaucoma. While for many years the research on the LC was essentially dependent on histology and modelling, a number of recent advances in optical coherence tomography (OCT) have dramatically improved the ability to visualise the LC, such that it is now possible to image the LC in vivo in humans and animals. In this review, we highlight recent advances in OCT imaging of the LC, in the technology, processing and analysis, and discuss the impact that these will have on the ability to diagnose and monitor glaucoma, as well as to expand our understanding of its pathophysiology. With this manuscript, we aspire to share our excitement on the achievements and potential of recent developments as well as advise caution regarding the challenges that remain before imaging of the LC and optic nerve can be used routinely in clinical practice. [ABSTRACT FROM AUTHOR]

Background Vascular risk factors have been associated with glaucomatous visual field progression. Aim We determined the relationship between vascular risk factors and structural glaucomatous progression using serial flicker chronoscopy images. Methods Two glaucoma fellowship-trained ophthalmologists, masked to temporal sequence, independently graded serial flicker chronoscopy images from one eye of a cohort of glaucoma patients for features of structural progression in this retrospective cohort study. After adjudication, simple and multiple logistic models were constructed to determine variables associated with increased odds of progression, including systolic blood pressure (BP), diastolic BP and mean ocular perfusion pressure. Results Seventy-two eyes of 72 patients were analysed. Patients with any form of structural progression (n=40) were older (67.0 vs 58.8 years; p=0.005) and had lower diastolic BP (71.8 vs 76.5 mm Hg; p=0.02) than patients without progression (n=32). In the univariable model, diastolic BP was associated with progressive retinal nerve fibre layer (RNFL) loss (OR=0.2 per 10 mm Hg, 95% CI 0.1 to 0.6, p<0.006) and neuroretinal rim loss (OR=0.4 per 10 mm Hg, 95% CI 0.2 to 0.8, p<0.01). Diastolic BP was also significant in the multivariable model for RNFL loss ( p=0.009) and neuroretinal rim loss (p=0.003). Conclusions This study is the first to use structural progression and flicker chronoscopy to identify vascular glaucoma risk factors. Older age and lower diastolic BP were associated with progression. By multivariable analysis diastolic BP was associated with RNFL and neuroretinal rim loss. These findings suggest that diastolic BP is associated with structural glaucomatous progression which may have implications for management. [ABSTRACT FROM AUTHOR]

A response from the author of the article "Cerebrospinal fluid exchange in the optic nerve in normal-tension glaucoma" is presented.

Glaucoma is a progressive optic neuropathy frequently associated with elevated intraocular pressure, ocular vascular changes and extracellular matrix remodelling at the optic nerve head and in the trabecular meshwork. The pathogenesis is multifactorial and complex, but many recent studies have suggested that transforming growth factor-β (TGF-β) plays a major role in the process. Significantly elevated levels of TGF-β have been identified in the anterior chamber of glaucomatous eyes. TGF-β has also been shown to directly cause increased intraocular pressure. It is believed that this occurs through complex interaction with the trabecular meshwork, leading to decreased aqueous humour outflow. These processes occur through specific interactions with various proteins and signalling molecules also present in ocular tissues. By understanding the role that TGF-β plays in the pathogenesis of glaucoma, alternative therapeutic agents can be developed, which target these pathways and improve and assist in the management of disease. This review will cover previous investigative studies and discuss the current understanding of TGF-β's role in glaucoma and how it may serve as a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Aim The aim of this cross-sectional study is to evaluate the macular and retinal nerve fibre layer (RNFL) thickness, as well as the electrical activity of the macula in female patients suffering from anorexia nervosa (AN) without visual failure. Material and methods 13 female patients (26 eyes) suffering from AN without visual failure and 20 age and sex-matched healthy female controls (40 eyes) were studied. For the measurement of the macula thickness and the electrical activity of the macula, the optical coherence tomography (OCT) and the multifocal electroretinogram were used respectively. Results The visual acuity, as well as the visual fields, the colour vision testing and the dark adaptation test of all patients were normal. However, the mean foveal thickness was 140.04 mm (vs 150.85 in the control group, p=0.005), and the RNFL thickness was limited to 116.42 mm in the superior area (vs 123.15 in the control group, p=0.372) and 121.08 mm in the inferior area (vs 137.6 in the control group, p<0.001) around the optic nerve. Also, the mean P1 response density amplitude of the foveal area was 159.04 nV/deg2 (vs 292.43 in the control group, p<0.0001), and the perifoveal area was 79.04 nV/deg2 (vs 82.63 in the control group, p=0.118). Conclusion The present study shows that in patients with AN, even without visual failure there is a decrease in macular and RNFL thickness, as well as a decrease in the electrical activity of the macula. [ABSTRACT FROM AUTHOR]

AIMS: To assess the additive effect of dorzolamide hydrochloride 2% on the diurnal intraocular pressure (IOP) curve and retrobulbar haemodynamics in patients with primary open-angle glaucoma (POAG) treated with morning-dosed bimatoprost 0.03%. METHODS: Twenty-five patients with POAG were evaluated in a prospective, single-masked study. After a 1 week run-in period with bimatoprost all patients were treated with bimatoprost dosed once in the morning for 1 month, after which dorzolamide was added twice daily for 2 months. Goldmann applanation IOP, arterial blood pressure (ABP) and heart rate were measured every 2 h for 24 h and diurnal ocular perfusion pressure (OPP) was calculated. Colour Doppler imaging (CDI) of the ophthalmic artery (OA) and the central retinal artery (CRA) was recorded five times daily. All measurements were taken after the two phases of treatment and were compared. RESULTS: The mean baseline IOP was 14.8±3.5 mm Hg. Mean IOP following bimatoprost monotherapy (12.8±2.9 mm Hg) and after 2 months of dorzolamide adjunctive therapy (12.2±2.6 mm Hg) were not statistically significantly different (p=0.544). Only at the 4:00 h time point was IOP significantly reduced using the bimatoprost/dorzolamide combined treatment (p=0.013). The 24 h IOP fluctuations were lower when dorzolamide was added (6.0±2.3 mm Hg vs 4.6±1.5 mm Hg, p=0.0016). Repeated analysis of variance detected a significant decrease of vascular resistance in the OA (p=0.0167) with adjunctive dorzolamide treatment. CONCLUSIONS: The addition of dorzolamide to morning-dosed bimatoprost had an additive hypotensive effect only on the night-time IOP curve at 4:00 h and resulted in a lower IOP fluctuation. Dorzolamide added to bimatoprost may reduce vascular resistance in the OA. [ABSTRACT FROM AUTHOR]

The article reports on the unique non-invasive technique for high resolution optical imaging of the eye is receiving global acclaim. By combining two high-resolution imaging technologies, the new technique provides doctors with 3-D images of the retina, macula and the optic nerve.

Aim: To compare the results of scanning laser polarimetry (GDx) with variable corneal compensation (VCC) and enhanced corneal compensation (FCC) when applied to myopic glaucomatous eyes. Methods: Forty glaucoma eyes with moderate myopia (between -3 and -6 D) and 35 glaucoma eyes with high myopia (-8 D or greater) were enrolled in this study. GDx VCC, GDx FCC and standard automated perimetry )SAP) were performed. The prevalence of an atypical retardation pattern (ARP), the typical scan score (TSS) and retinal nerve fibre layer (HNFL) thickness were compared between VCC and FCC in both groups of myopic subjects. A correlation analysis between RNFL thickness and visual sensitivity was also conducted. Results: In both myopic groups, the mean TSS is significantly lower (p<0.0001(, and the prevalence of ARP was significantly higher (p<0.000l( by VCC scans than by ECC scans. Temporal, superior, nasal, inferior, temporal (TSNIT) average and temporal average thickness showed significantly higher values (p<0.001) by VCC than by ECC. A statistically significant association was observed between TSNIT average and mean deviation of SAP by ECC scan. Conclusions: ECC scans showed a better retardation pattern and structure-function relationship than did VCC, and ECC appeared to be more suitable for RNFL assessment in glaucomatous eyes that are moderately to highly myopic. [ABSTRACT FROM AUTHOR]

Background/aims: To investigate the association of biometric and systemic variables with optic disc characteristics in Chinese Singaporean adults. Methods: Ocular, biometric and medical data including intraocular pressure, refractive error, keratometry, axial length IAL), anterior chamber depth, corneal and lens thickness as well as optic disc data (using planimetry of stereo-photographs) were obtained from 622 normal subjects aged ~4O years from the Tanjong Pagar glaucoma survey of Singapore. Results: Disc area (DA) was positively associated with AL and height but was unrelated to corneal thickness. Following adjustment for lOP and sex, DA remained positively associated with AL, height and age. Neuroretinal rim area )RA) was also significantly and positively associated with AL and also with height. RA was negatively associated with lOP and was unrelated to blood pressure, history of diabetes, myocardial infarction, stroke or migraine. Conclusions: These data on a Chinese Singaporean population identify height and axial length of the globe as significantly associated with rim area of the disc. These features should be taken into account in statistical assessments of optic nerve head morphometry. This may improve the discriminative ability of image analysis to detect glaucomatous changes. In addition, we identified a statistically significant but small inverse association between rim area and lOP within the normal statistical range. [ABSTRACT FROM AUTHOR]

Aims: We investigated the effect of several Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), on the preoptic nerve oxygen tension (ONPo2), as indomethacin previously has demonstrated a strong decreasing effect on ONPo2. We tested whether these NSAIDs, like indomethacin, also reduce the increasing effect of dorzolamide on ONPo2. Methods: ONPo2 was measured 0.5 mm above the optic disc in 23 domestic pigs (26-36 kg) with a polarographic oxygen-sensitive electrode. One of the following NSAIDs was administered intravenously as increasing doses or as one large dose: indomethacin, ibuprofen, diclofenac, ketoprofen, parecyclo-oxygenase-2 inhibitor and lornoxicam. Indomethacin was both tested alone and after preceding administration of the other NSAIDs. Dorzolamide was also tested after preceding administration of NSAIDs different from indomethacin. Results: Indomethacin decreased ONPo2 significantly in a dose-dependent manner. None of the other NSAIDs produced any effect on the ONPo2 (p>>0.05; n = 17). No difference was found between the effect of indomethacin injected alone, and after preceding administration of the other NSAIDs. Intravenous dorzolamide (500 mg) increased ONPo2 by 32 (7)% (n = 7; p<0.001) after preceding administration of several NSAIDs different from indomethacin. Conclusions: Indomethacin decreased ONPo2, while the other NSAIDs showed no effect on ONPo2, and they did not affect the effect of indomethacin. The hypoxic effect of indomethacin must be due to another mechanism than cyclo-oxygenase inhibition. The effect of dorzolamide on ONPo2 is not related to prostaglandin production. [ABSTRACT FROM AUTHOR]

Aim: To investigate the effect of dopamine on retinal and choroidal blood flow in humans. Methods: We investigated the effect of two doses of intravenous dopamine (5 and 10 μg/kg/min) via a randomised double-masked crossover study in 1 2 healthy subjects chosen from a total of 16. Blood flow parameters in retina, optic nerve head and choroid were assessed with bi-directional laser Doppler velocimetry, laser Doppler flowmetry and laser interferometric measurement of fundus pulsation amplitude, respectively. Results: Intravenous dopamine dose-dependently increased retinal blood cell velocity and hindus pulsation amplitude (p<0.001). At the highest administered dose red blood cell velocity in retinal vessels increased by 37% and hindus pulsation amplitude by 24%. By contrast, optic nerve head blood flow did not change with dopamine administration. Conclusions: Our data indicate that dopamine has a pronounced enhancing effect on the retinal perfusion in humans. Further studies are required to establish the exact role of dopamine in the regulation of choroidal and optic nerve head blood flow. [ABSTRACT FROM AUTHOR]

Aims: To demonstrate a constriction in the central retinal vein in the region of the lamina cribrosa. Methods: A prospective comparative interventional study of 13 controls and 19 patients with central retinal vein occlusion (CRVO) using colour Doppler imaging of the central retinal artery and vein in the region of the lamina cribrosa and optic nerve posterior to the globe. Results: In controls peak velocities in the vein were higher in the region of the lamina cribrosa than the optic nerve, mean 175 mm/second (mm/s) and 49 mm/s respectively, p<0.0001. The velocities in the artery were also higher in the region of the lamina cribrosa, mean 122 mm/s and 92 mm/s, p=0.007. The variability of the velocities in the region of the lamina cribrosa was 7.4% in the artery and 15.2% in the vein. The mean ratio of the velocities in the vein (4.2 (SD 2.1)) was significantly higher than the mean ratio in the artery (1 .4 (SD 0.4), p<0.0001). In CRYO, the mean ratio in the vein was lower in the affected eyes (2.2 (SD 1.9), p<0.01) and fellow unaffected eyes (2.2 (SD 1.0), p=0.003) than controls. The values were stable in eight after radial optic neurotomy. Conclusion: The presence of a constriction of the vein in the region of the lamina cribrosa can be inferred from the presence of higher blood velocities at this site than further back in the optic nerve. In CRVO there may be a more uniform narrowing of the vein along its course in the nerve. Neurotomy did not affect the measurements. [ABSTRACT FROM AUTHOR]

Aim: To create ‘slotted eye plaques’ for the treatment of juxtapapillary and circumpapillary intraocular tumours. Methods: Eye plaques were altered such that 8 mm-wide slots (variable length) were created to accommodate the orbital portion of the optic nerve. Thus, as the nerve entered the slot, the plaque's posterior margin extended beyond the optic disc. Radioactive seeds were affixed around the slot, surrounding the juxtapapillary and posterior tumour margins. Results: As proof of principle, three patients with choroidal melanomas that encircled or were in contact with the optic disc (considered untreatoble with a notched eye plaque) were considered to be initial candidates for slotted-plaque radiotherapy. Preoperative three-dimensional C-scan imaging of their optic nerve sheath diameters insured that they would fit in the slotted plaque. Intraoperative ultrasound imaging was used to confirm proper plaque placement. Radiation dosimetry modelling showed that all tumour tissue received a minimum of 85 Gy (despite the gap created by the slot). With relatively short-term follow-up, there has been no evidence of ocular ischaemia, tumour growth or complications attributable to the use of slotted-plaque radiation therapy. Conclusion: Slotted plaques accommodate the retrobulbar optic nerve into the device and thereby shift the treatment zone to improve coverage of both juxtapapillary and circumpapillary intraocular tumours. [ABSTRACT FROM AUTHOR]

Aim: To identify the presence, and origin, of any "dissociating factors" inherent to the techniques for evaluating progression that mask the relationship between structural and functional progression in open-angle glaucoma (OAG). Methods: 23 patients (14 with OAG and 9 with ocular hypertension (OHT)) who had received serial Heidelberg Retina Tomograph (HRT II) and Humphrey Field Analyser (HFA) examinations for ⩾5 years (mean 78.4 months (SD 9.5), range 60-101 months) were identified. Evidence of progressive disease was retrospectively evaluated in one eye of each patient using the Topographic Change Analysis (TCA) and Glaucoma Progression Analysis (GPA) for the HRT II and HFA, respectively. Results: Six patients were stable by both techniques; four exhibited both structural and functional progression; seven exhibited structural progression, only, and six showed functional progression, only. Three types of dissociating factors were identified. TCA failed to identify progressive structural damage in the presence of advanced optic nerve head damage. GPA failed to identify progressive functional damage at stimulus locations, with sensitivities exhibiting test-retest variability beyond the maximum stimulus luminance of the perimeter, and where a perimetric learning effect was apparent. Conclusion: The three dissociating factors accounted for nine of the 13 patients who exhibited a lack of concordance between structural and functional progressive damage. [ABSTRACT FROM AUTHOR]

Editorial. Focuses on the efforts made to analyze the complex vasculature of the eye. Reliance on fluorescein angiography; Studies on the circulation of the optic nerve; Determination of how blood flow can change through a variety of clinical settings.

The pathology of glaucoma has been extensively studied at the level of the retina and optic nerve head. Here the first clinicopathological case of human glaucoma is reported demonstrating degenerative changes in the brain involving the intracranial optic nerve, lateral geniculate nucleus, and visual cortex. Pathological evidence of neural degeneration in this patient is correlated with clinical, optic nerve head, visual field, and neuroradialogy findings. Neuropathology in the glaucoma brain is compared to age matched controls. In the presence of advanced human glaucoma with 50% visual field loss, neural damage is evident in multiple vision stations within the brain. [ABSTRACT FROM AUTHOR]

Aim: To describe unique linear deposits on the surface of posterior chamber intraocular lenses (IOLs) occurring alter implantation through a hexagonal cartridge. Methods: Five ACR6D SE IOLs (Corneal Laboratories, Pringy, France) were injected/implanted through hexagonal cartridges. Two of these were injected into a petri dish and the remaining three were inserted into the evacuated capsular bag of cadaver eyes. In addition, three other ACR6D SE IOLs were injected into a petri dish through round cartridges. The latter served as controls. Results: All lenses that were injected/implanted through the hexagonal cartridges demonstrated linear deposits on the posterior surface of the IOL optic component. The lOLs that were injected through the round cartridges had no deposits. All the hexagonal cartridges showed signs of internal cracking. None of the round cartridges were cracked. Conclusion: Implantation of at least one IOL model, the ACR6D SE IOL, through a hexagonal cartridge can result in linear deposits on the posterior optical surface of the IOL. The shape of the cartridge appears to be a significant factor in causing the depositions. [ABSTRACT FROM AUTHOR]

Aim: To establish the epidemiology of the grey crescent in a white population within the age range most susceptible to glaucoma. Methods: Bruce Shields was first to use this term to describe a localised, physiological pigmentation of the optic nerve neuroretinal rim tissue that is distinct from peripapillary pigmentation. An experienced glaucomatologist (KFD) evaluated stereofundus photographs of the participants of the Reykjavik Eye Study (RES)-a random sample from the national population census including people 50 years and older. 1012 right eyes could be evaluated for grey crescent. Results: The prevalence of grey crescent in the right eyes was 22.0% (95% Cl 10 to 25). It was more commonly found in women (27.0%: 95% Cl 23 to 30) than in men (17.0%: 95% CI 14 to 21), and was most often located temporally (36.9%), 360° (15.9%), or nasally (15.4%). The spherical equivalent was +1.30 dioptres (D) for those with and +0.80 D for those without grey crescent (p = 0.002), respectively. Vertical optic disc diameters were 0.203 v 0.195 units (p<0.001). There was no difference in the prevalence of grey crescent in glaucomatous or non-glaucomatous eyes (OR =1.05,95% Cl 0.49 to 2.26). The prevalence of a grey crescent was inversely related to the prevalence of peripapillary atrophy (p=0.001). Conclusions: The grey crescent needs to be recognised as a physiological variant in order to avoid falsely labelling eyes as having glaucomatous optic nerve damage. [ABSTRACT FROM AUTHOR]

Aim: To study the normal distributions of mitochondria and voltage gated Na(+) channels in the human optic nerve head in order to gain insight into the potential mechanisms of optic nerve dysfunction seen in the inherited optic neuropathies. METHODS: Five fresh frozen human optic nerves were studied. Longitudinally orientated, serial cryosections of optic nerve head were cut for mitochondrial enzyme histochemistry and immunolabelling for cytochrome c oxidase (COX) subunits and voltage gated Na(+) channel subtypes (Na(v) 1.1, 1.2, 1.3, and 1.6). RESULTS: A high density of voltage gated Na(+) channels (subtypes Na(v) 1.1, 1.3, and 1.6) in the unmyelinated, prelaminar, and laminar optic nerve was found. This distribution co-localised both with areas of high COX activity and strong immunolabelling for COX subunits I and IV. CONCLUSIONS: Increased numbers of mitochondria in the prelaminar optic nerve have previously been interpreted as indicating a mechanical hold up of axoplasmic flow at the lamina cribrosa. These results suggest that this increased mitochondrial density serves the higher energy requirements for electrical conduction in unmyelinated axons in the prelaminar and laminar optic nerve and is not a reflection of any mechanical restriction. This could explain why optic neuropathies typically occur in primary inherited mitochondrial diseases such as Leber's hereditary optic neuropathy, myoclonic epilepsy with ragged red fibres (MERRF), and Leigh's syndrome. Secondary mitochondrial dysfunction has also been reported in dominant optic atrophy, Friedreich's ataxia, tobacco alcohol amblyopia, Cuban epidemic optic neuropathy, and chloramphenicol optic neuropathy. These diseases are rare but these findings challenge the traditional theories of optic nerve structure and function and may suggest an alternative approach to the study of commoner optic neuropathies such as glaucoma. [ABSTRACT FROM AUTHOR]

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... [ABSTRACT FROM AUTHOR]

Aim: To evaluate the morphology of the optic nerve head in an unselected population group in south India. Methods: The study included 70 subjects forming a population based sample, selected in a random manner. Mean age was 47.5 (SD 8.7) years, mean refractive error measured -0.07 (1.11) dioptres (range -4.50 to +2.50 dioptres). Optic disc slides were morphometrically analysed. Results: Mean optic disc area measured 2.58 (0.65) mm². It was statistically independent of age and refractive error. Optic disc shape was slightly vertically oval. Mean neuroretinol rim area was 1.60 (0.37) mm². It was significantly and positively correlated with optic disc size and optic cup size. It was independent of age, sex, refractive error, and axial length. In all subjects included in the study, the rim was smallest in the temporal horizontal optic disc sector. Mean horizontal cup/disc diameter ratio (0.66 (0.07)) was significantly (p<0.001) higher than the mean vertical cup/disc diameter ratio (0.56 (0.08)). Both ratios were highly significantly (p <0.001) and positively correlated with optic disc size. The α zone of parapapillary atrophy (0.84 (0.29) mm²), and β zone (0.13 (0.38) mm²), respectively, occurred in 69 (98.6%) subjects and in eight (11.4%) subjects, respectively. They were significantly larger in the temporal horizontal sector. The α zone was significantly (p<0.001) larger and occurred significantly more often than β zone. Retinal arterioles and venules were wider, and in spatial correlation, the visibility of the retinal nerve fibre layer was significantly better, in the temporal inferior disc arcade and the temporal superior arcade than in the nasal superior arcade and the nasal inferior vessel arcade. Except for the absolute size measurements these optic nerve head parameters did not differ markedly (p >0.05) from the values found in white people. Conclusions: South Indians and white people do not show marked differences... [ABSTRACT FROM AUTHOR]

Background: Bilateral optic nerve hypoplasia (BONH) is often associated with other central nervous system midline abnormalities (septo-optic dysplasia). Hormonal dysfunction, caused by anterior (cortisol) and posterior (ADH) pituitary involvement, can be sudden, severe, and life threatening. Methods: Case series. Three cases of septo-optic dysplasia (SOD) presenting as infantile infection with associated diabetes insipidus are reported. The diagnosis of SOD was suspected only after ophthalmological evaluation; further evaluation led to the diagnosis of panhypopituitarism. Conclusions: A high index of suspicion is required to diagnose SOD in children when the disorder presents with infantile infection and hypernatraemia. Early warning signs of neonatal jaundice and hypoglycaemia should prompt ophthalmological evaluation. [ABSTRACT FROM AUTHOR]

The article discusses a research that compared the disc damage likelihood scale with the cup/disc ratio as a way to describe the glaucomatous optic nerve. It references a study by Danesh-Meyer and colleagues published in this same issue. It then discusses the superiority of the disc damage likelihood scale.optic disc

This article reports on developments related to the field of ophthalmology. A unique new non-invasive technique for high resolution optical imaging of the eye is receiving global acclaim. The new technique provides doctors with 3-D images of the retina, macula and the optic nerve. The latest issue of the journal "Community Eye Health" discusses new developments in the control of trachoma. The World Ophthalmology Congress (which is replacing the International Congress of Ophthalmology) is meeting in February 2006 in Brazil.