Ophthalmoscopic measurement of the optic disc

PURPOSE: The authors evaluated whether the optic disc dimensions can be measured directly by ophthalmoscopy without the use of a fundus camera or special ophthalmoscope. MATERIALS AND METHODS: The horizontal and vertical disc diameters were measured ophthalmoscopically in 158 eyes of 95 subjects using a standard Goldmann three-mirror contact lens and a commercial slit lamp with adjustable length of the beam. The refractive error ranged from -7.25 to 3.5 diopters. Based on these direct measurements, the authors calculated the disc area by applying a modified formula for an ellipse, where area = pi/4 x the horizontal diameter x the vertical diameter. Additionally, the authors determined by planimetry the diameters and area of the disc on color photographs after correcting the ocular and photographic magnification. RESULTS: The values of the disc diameters as determined by photography were x1.27 larger than those measured with the Goldmann contact lens. Taking into account this constant correction factor of 1.27 for all eyes examined, the disc diameters, as measured by the Goldmann lens, varied by 0.11 +/- 0.06 mm or 5.8% +/- 3.5% from the values measured on the photographs. This error decreased slightly (P = 0.04) with increasing disc size. It was independent of the refractive error. The calculated disc area based on the ophthalmoscopically determined disc diameters differed by 9.4% +/- 6.6% from the disc area as measured by planimetry on the photographs. CONCLUSIONS: For clinical purposes, the optic disc and other structures of the posterior fundus can be measured by ophthalmoscopy using a Goldmann contact lens and a slit lamp with adjustable beam length. The optic disc area can be calculated by the formula: horizontal disc diameter x vertical disc diameter x pi/4.     

Medulloepithelioma of the optic nerve head

Medulloepithelioma of the optic nerve is a rare developmental tumor. We describe a 2-year-old boy with profound loss of vision associated with a visible tumor of the optic nerve head in his left eye. A clinically diagnosed retinoblastoma necessitated left eye enucleation. The histopathological diagnosis was malignant medulloepithelioma that was incompletely resected. Further tumor resection was required, and the patient received adjunctive chemotherapy and radiotherapy. Four years after treatment, the patient has neither clinical nor radiological evidence of tumor.     

Decompression of the optic nerve sheath

Optic nerve sheath decompression (ONSD) has become a more frequently performed surgical procedure in recent years. We describe the surgical techniques and complications and we detail the indications of ONSD in pseudotumor cerebri, ischemic optic neuropathy due to arteriosclerosis and other etiologies under investigation. With a 2% risk of postoperative blindness, this procedure must be indicated only in case of severe visual loss and performed by surgeon experienced to orbital surgery.     

Large optic nerve glioma

Twelve cases of optic nerve glioma seen over a 28 year period are analysed herein in this autopsy study.     

Relation between size of optic disc and thickness of retinal nerve fibre layer in normal subjects

The genus Clinostomum is a cause of parasitic laryngo-pharyngitis. We report the 15th case of Clinostomum sp. infection in Japan. A 29-year-old female visited our hospital because of throat discomfort and expectoration of a worm by sneezing on November 17, 1997. The pharyngitis was caused by the worm. The worm was morphologically identified as the adult of the genus Clinostomum.     

Inflammation of the optic nerve in the fluoroangiographic picture

Recent research has related pedalling frequency to perceived exertion, indicating that subjects pedalling at higher frequencies tend to perceive lower levels of exertion. If tests administered at higher pedalling speeds are valid, then more accurate data on extremely low fit individuals might be possible. The purpose of this study was to determine the validity of the Wahlund-Sjostrand W170 test administered at 50 and 80 rpm. Maximal oxygen intake was determined for thirty male volunteer college students using standard open-circuit techniques. W170 tests were administered at 50 and 80 rpm using standard test protocol. The results indicated a differential effect of pedalling speed upon the validity of the W170 tests. Validity coefficients of rxy = 0.73 and rxy = 0.64 were found for the 50 and 80 rpm tests, respectively. Maximal oxygen intake predicted from the W170 test administered at 80 rpm was significantly different from both the criterion maximal oxygen intake and the W170 prediction at 50 rpm. This difference was attributed to a significantly higher heart rate response to 80 rpm tests at the lower workload of 600 kpm/min. It was concluded that more valid W170 tests are attained at the conventional pedalling speed of 50 rpm.     

Chiasmatic specificity in the regenerating mammalian optic nerve

Bone-resorbing multinucleated cells were efficiently formed in primary culture of cells isolated from synovial tissues of patients with rheumatoid arthritis in 2-3 weeks in the presence of 1,25(OH)2vitaminD3 without any additional stromal cells, and that formation was further facilitated by macrophage-colony stimulating factor. Furthermore, we show that osteoclast-like cells are formed in co-culture of peripheral blood mononuclear cells and rheumatoid synovial fibroblasts obtained by continued sub-cultures. The multinucleated cells showed all the phenotypical and functional characteristics of osteoclasts including the expression of tartrate resistant acid phosphatase, vitronectin receptors, receptors for human calcitonin and the ability to resorb bone. These results indicate that synovial macrophages are capable of differentiating into osteoclasts in the presence of rheumatoid synovial fibroblasts which can support differentiation of monocytes/ macrophages, implicating that osteoclasts generated within the synovial membrane are probably involved in bone destruction in rheumatoid arthritis.     

Increase in extracellular calcium in the optic tectum of fish after optic nerve transection

In this study the extracellular distribution of cytochemically generated calcium reaction product in the denervated optic tectum of a cichild fish (Oreochromis mossambicus) was investigated. The left optic nerve had been transected and the fish (5 per experimental condition) maintained for 2, 10 and 21 days. The amount of the calcium-containing precipitates was estimated using energy-filtering transmission electron microscopy (EFTEM) and image analysis. A special degeneration type of the optic terminals (neurofibrillar hypertrophy) was found which seems to be rare in other teleosts and was therefore chosen for quantification of the calcium deposits. These terminals are surrounded by astroglial processes and the calcium reaction product in the extracellular spaces between these glial processes and the terminals was measured and compared to normal optic terminals in nonoperated controls. A distinct and significant increase in the amount of calcium deposits was found 2 and 10 days after surgery which decreased to control levels after 21 days. This rise of deposits around the degenerating terminals was very local as arbitrarily selected extracellular spaces near these terminals showed values which were at the level of the nonoperated controls. Therefore, a transient and local increase in extracellular calcium precipitates was found after optic nerve transection which affected only the degenerating synapses.     

Contemporary methods for functional analysis of the optic nerve

Complex methods of statistic analysis for parameters of automated perimetry and visual evoked potentials were presented. The examinations were performed in 14 patients with compressive visual neuropathy, in 14 patients with optic neuritis, in 20 patients with demyelinative visual neuropathy and in 20 patients with optic nerve atrophy. Multidimensional analysis of variance (MANOVA) was performed. The methods proved useful for differential diagnosis of optic neuropathy.     

Adrenoleukodystrophy with disease of the eye and optic nerve

Adrenoleukodystrophy is an X-chromosome-linked recessive disease characterized by primary atrophy of the adrenal glands with or without Addison's disease and low plasma cortisol levels, and a degeneration of white matter of the central nervous system with blindness. In suspected cases of adrenoleukodystrophy an impaired rise in plasma cortisol levels after adrenocorticotrophin stimulation may be diagnostic. With the electron microscope, pathognomonic intracytoplasmic lamellar inclusions have been seen in adrenal cortical cells, peripheral nerve Schwann's cells, testicular interstitial cells, and in macrophages of the brain. Adrenoleukodystrophy appears to be a genetically determined lipid storage disease with an error in membrane sterol metabolism. A 10-year-old boy with adrenoleukodystrophy had visual loss, a prominent early symptom. The ocular abnormality consisted of a disproportionate loss of nerve fibers from the macular region. No intracytoplasmic lamellar inclusions were identified in cells representing macrophages within the optic nerve. They contained myelin debris suggestive of end-stage disease.     

Hypoplasia of the optic nerve in association with porencephaly

Two cases of hypoplasia of the optic nerve associated with porencephaly are described. The clinicopathological correlation of the double ring sign is presented and the possible mechanism of optic nerve hypoplasia being a secondary degeneration is discussed.     

Progressive growth in melanocytoma of the optic nerve head

The authors describe the method of closure of laparotomic wounds by means of an atraumatic continuous PDS loop suture. Based on evaluation of a group of 166 patients they appreciate the positive aspects of the technique of this suture, in particular the speed, easy implementation and safe closure of laparotomy. As regard the sewing material, they value highly the quality of atraumatic fibres which are firm and do not irritate the tissues.     

Platelet-derived growth factor B-chain expression in the rat retina and optic nerve: distribution and changes after transection of the optic nerve

To test the possible involvement of platelet-derived growth factor B-chain (PDGF-B) in anterograde and retrograde degenerations of the CNS neurons, we studied the changes of PDGF-B localization and its mRNA expression in the rat retina and optic nerve (ON) after unilateral ON transection, using immunohistochemistry and in situ hybridization. In the control retinas immunoreactivity for PDGF-B and its mRNA expression were localized in the retinal ganglion cells (RGCs) and the nerve fiber layer. After ON transection PDGF-B immunoreactivity in the nerve fiber layer started to decrease on post-injury day 3 or 4. Atrophic changes in the RGCs started on day 5 just after the decrease of PDGF expression, and thereafter the RGC number decreased. In the longitudinal section of the ON rostral to the transected site, swollen axons showed intense PDGF-B immunoreactivity and macrophages, and some glial cells revealed a significant increase in both immunoreactivity and hybridization signals. Based on these findings, we hypothesized that the decrease in PDGF-B in RGCs after axotomy causes the loss of RGCs, and that increased PDGF-B expression in the ON plays a role in the cascade of tissue reactions following ON transection.     

Transient neovascularisation of the frog retina during optic nerve regeneration

In conditions such as diabetic retinopathy, degenerative events in the retina are associated with neovascularisation. It is well established that a proportion of retinal ganglion cells die during optic nerve regeneration in the frog. The present study has determined whether neovascularisation takes place during this regenerative process. To do so, the pattern of blood vessels overlying the retinal ganglion cell layer was analysed in the frog Litoria (Hyla) moorei. We examined normal animals and those undergoing optic nerve regeneration following nerve crush. Blood vessels were visualised by perfusion with Indian ink and retinae were prepared as wholeamounts. In normal animals, the vascular tree was found to lie superficial to the nerve fibre layer and was more complex in regions overlying the area centralis and visual streak. After nerve crush, abnormal blood vessels transiently formed between the existing branches of the vascular tree. The new vessels were concentrated as an annulus centred on the optic nerve head and over the area centralis in midtemporal retina. The neovascularisation became most extensive between 6 and 10 weeks postcrush and disappeared by 12 weeks. The spatiotemporal sequence of neovascularisation suggests that it is triggered by accumulations of degenerating material formed as a proportion of the ganglion cells die during optic nerve regeneration.     

Bilateral optic nerve meningioma. Case report

A case of bilateral optic nerve meningioma is reported. The onset of the clinical symptoms, at age 27, resembled unilateral optic neuritis with papilledema, leading to bilateral amaurosis with optic atrophy 4 years later. Skull X-ray revealed a "blistering' type of bone reaction. In the carotid angiogram, the ophthalmic artery appeared quite enlarged and displaced. The CT scan showed a fusiform enlargement of both optic nerves. Pathological diagnosis was based upon an optic nerve biopsy. Including the present case, only 12 instances of bilateral optic nerve meningioma have been reported.