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PubMed2006

Visual field preservation after multisession cyberknife radiosurgery for perioptic lesions.

OBJECTIVE: The restricted radiation tolerance of the anterior visual pathways represents a unique challenge for ablating adjacent lesions with single-session radiosurgery. Although preliminary studies have recently demonstrated that multisession radiosurgery for selected perioptic tumors is both safe and effective, the number of patients in these clinical series was modest and the length of follow-up limited. The current retrospective study is intended to help address these shortcomings. METHODS: Forty-nine consecutive patients with meningioma (n = 27), pituitary adenoma (n = 19), craniopharyngioma (n = 2), or mixed germ cell tumor (n = 1) situated within 2 mm of a "short segment" of the optic apparatus underwent multisession image-guided radiosurgery at Stanford University Medical Center. Thirty-nine of these patients had previous subtotal surgical resection, and six had previously been treated with conventional fractionated radiotherapy (6). CyberKnife radiosurgery was delivered in two to five sessions to an average tumor volume of 7.7 cm3 and a cumulative average marginal dose of 20.3 Gy. Formal visual testing and clinical examinations were performed before treatment and at follow-up intervals beginning at 6 months. RESULTS: After a mean visual field follow-up of 49 months (range, 6-96 mo), vision was unchanged postradiosurgery in 38 patients, improved in eight (16%), and worse in three (6%). In each instance, visual deterioration was accompanied by tumor progression that ultimately resulted in patient death. However, one of these patients, who had a multiply recurrent adrenocorticotropic hormone-secreting pituitary adenoma, initially experienced early visual loss without significant tumor progression after both a previous course of radiotherapy and three separate sessions of radiosurgery. After a mean magnetic resonance imaging follow-up period of 46 months, tumor volume was stable or smaller in all other cases. Two patients died of unrelated nonbrain causes. CONCLUSION: Multisession radiosurgery resulted in high rates of tumor control and preservation of visual function in this group of perioptic tumors. Ninety-four percent of patients retained or improved preradiosurgical vision. This intermediate-term experience reinforces the findings from earlier studies that suggested that multisession radiosurgery can be a safe and effective alternative to either surgery or fractionated radiotherapy for selected lesions immediately adjacent to short segments of the optic apparatus.

Adolescent↗

PubMedDate not supplied

[Ophthalmologic evaluation of VDT/PC operators: approach to the diagnosis with neural networks].

The present study was performed to build a neural network as a diagnostic tool to aid ophthalmologic examination of VDT/PC operators. The network was built on anamnesic and ophthalmologic data (visual acuity and mesopic vision, contrast sensitivity) from 278 VDT/pC operators and is able to predict 88% of total cases who need specialist attention, when ocular pathologies are also present, and 91% when only refraction defects are present. The tests chosen for this study are not useful to build a very sensitive discriminant model. This study confirm the absence for useful ophthalmologic tests in screening of VDT/PC operators, particularly when ocular pathologies are present without refractive errors. For their capacity to translate on a clinical-pratic plane knowledge obtained through studies conducted on large populations, the neural networks seem to be a good diagnostic tool.

Computer Terminals↗

PubMed1999

Long-term sequelae after surgery for orbital floor fractures.

A surgical technique involving exact repositioning and rigid fixation is required for the reduction of fractures of the orbital floor. Even then, sequelae may be present long after the trauma. The aim of this study was to establish the frequency and type of sequelae after surgery for orbital floor fractures and to investigate the extent to which the method of surgery had any impact on the severity of the sequelae. A questionnaire was sent to all 107 patients (response rate 77%) 1 to 5 years after the injury. Further clinical data were obtained from the patients' charts. Eighty-three percent of the patients were affected by some kind of permanent sequelae in terms of sensibility, vision, and/or physical appearance. A high frequency of diplopia (36%) was related to the reconstruction of the orbital floor with a temporary "supporting" antral packing in the maxillary sinus, a technique which has now been abandoned at our department in favor of orbital restoration with sheets of porous polyethylene. Our conclusion is that, because long-term sequelae are common, the surgical technique must be subjected to continuous quality control to minimize future problems for this group of patients.

Adolescent↗

PubMed2000

Internet resources and web pages for pediatric surgeons.

The Internet, the largest network of connected computers, provides immediate, dynamic, and downloadable information. By re-architecturing the work place and becoming familiar with Internet resources, pediatric surgeons have anticipated the informatics capabilities of this computer-based technology creating a new vision of work and organization in such areas as patient care, teaching, and research. This review aims to highlight how Internet navigational technology can be a useful educational resource in pediatric surgery, examines web pages of interest, and defines ideas of network communication. Basic Internet resources are electronic mail, discussion groups, file transfer, and the Worldwide Web (WWW). Electronic mailing is the most useful resource extending the avenue of learning to an international audience through news or list-servers groups. Pediatric Surgery List Server, the most popular discussion group, is a constant forum for exchange of ideas, difficult cases, consensus on management, and development of our specialty. The WWW provides an all-in-one medium of text, image, sound, and video. Associations, departments, educational sites, organizations, peer-reviewed scientific journals and Medline database web pages of prime interest to pediatric surgeons have been developing at an amazing pace. Future developments of technological advance nurturing our specialty will consist of online journals, telemedicine, international chatting, computer-based training for surgical education, and centralization of cyberspace information into database search sites.

Child↗

PubMed2005

Vogt-Koyanagi-Harada syndrome with intracranial meningioma: an as yet unreported association.

CASE REPORT: We document a previously unreported association of Vogt-Koyanagi-Harada (VKH) syndrome with intracranial meningioma. A female patient with diminished vision, exudative retinal detachment, and headache was diagnosed with VKH syndrome, more precisely a Harada form of disease with intracranial meningioma, on the basis of exudative retinal detachment, typical fundus fluorescein findings, and magnetic resonance imaging. With intravenous steroid therapy, visual acuity improved and the detachment settled within a week. At 3 months, the detachment recurred but improved after retreatment. At 1 year, the tumour was unchanged in size. COMMENTS: VKH syndrome may be associated with intracranial meningioma that may affect the patient's overall morbidity or mortality.

Adult↗

PubMed1998

Stereoscopic depth perception in the owl.

It is unclear whether the neural algorithm that underlies stereoscopic vision in birds incorporates both low level (camouflage breaking) and high level (depth ordering) comparisons of information available to each of the eyes. Both visual functions were successfully tested by examining transitive inference performance in two barn owls trained to discriminate static Julesz random dot stereograms, thus demonstrating a capacity to detect relative depth using fine retinal disparity as the sole cue for discrimination. Our behavioral tests provide strong evidence that the barn owl possesses global stereopsis comparable to that found in the macaque monkey--the owl's best stereoacuity was 2 min of arc.

Algorithms↗

PubMed1979

Benign intracranial hypertension: clinical features and diagnosis using computed tomography and treatment.

A series of 28 patients presenting with benign intracranial hypertension is reported. The diagnosis was based on normal CT scanning appearances, including ventricular size, and it is stressed that no further neuroradiological investigations were required. Conservative treatment is shown to be effective in the majority of patients. It is, however, suggested that surgical intervention in the form of a shunting procedure (lumboperitoneal in our cases) might prove necessary, if vision remains in jeopardy.

Acetazolamide↗

PubMed1989

[CT localization of foreign intra-ocular bodies].

In the course of three years from the total number of 124 CT examinations indicated by the Ophthalmological Department of the Regional Hospital in Ustí nad Labem ten examinations of the orbit with an intraocular foreign body were made. Based on a group of 10 eyes the authors present a report of their hitherto assembled experience with the use of computed tomography in the diagnosis of intraocular foreign bodies. They draw attention to the advantages but also certain limitations of the location of foreign bodies by CT. In two of 10 cases the foreign body was located incorrectly by CT in the bulbar wall--although it was retrobulbar. In the remaining eight cases the CT examination was a great asset and contributed greatly to successful operation. 50% of the patients have after operation a vision of 6/6.

Adolescent↗

PubMed1995

Preoperative shunts in suprasellar tumours.

A series of 22 cases of large suprasellar tumours was studied retrospectively. These patients had undergone a preoperative shunt to facilitate surgical exposure of the tumour and to reduce intracranial pressure in critically ill patients. Our observations on the clinical progress of these patients following the shunt is analysed. Nine patients worsened to a varying degree following insertion of the shunt. Seven patients became drowsy, one developed worsening of vision and a hemiparesis, and one became an akinetic mute. The worsening was probably related to alteration of intracranial pressure dynamics and resultant compression in the hypothalamic region by subtle superior migration of the tumour. Operative difficulties were encountered during the dissection of the tumour from the neural structures in these cases. We conclude that with the availability of modern decongestive measures and basal surgical exposures, preoperative shunting is rarely indicated and can be occasionally dangerous. In the absence of actual proof, it is postulated that the secondary ventricular enlargement appears to be a protective mechanism of the brain helping to reduce tumour pressure on the basal forebrain structures.

Adult↗

PubMed1984

User friendly system for electrodiagnosis.

A laboratory built computer system for clinical electrophysiology of vision is described to illustrate how modern technology may ease the task of handling otherwise rather complicated electronic equipment and of elaborating the data obtained. An example is given of a procedure for clinical electroretinography in which the task of the operator is virtually confined to using a single command letter, which is specified in continuously updated instructions displayed on a monitor. After the patient has left, the operator checks and if necessary corrects the automatically defined maxima of a and b waves of the electroretinogram. The print-out consists of graphs of amplitude and latency versus stimulus intensity in which the normal range is indicated. The task of the operator during an EOG measurement is confined to checking the collaboration of the patient, since the complete procedure including the elaboration of the data is automated.

Computers↗

PubMed1986

Human factors design of a video monitor emulator and display (VMED) for visually impaired computer users.

This paper describes research conducted by the Atlanta VA Medical Center in the area of visual impairment and computer usage--in particular, work on the design of a device that reformats computer video output for use by persons with limited usable vision. The objective of the current project is to design, build, and test a video/video control interface that can be connected to and will reformat the video data of any general-purpose computer/word processor. The objectives of this work are to complete a human factors analysis of types of tasks performed on computers/word processors, and to design and build a universal interface that implements the results of the aforementioned study.

Algorithms↗

PubMed1998

Effect of surgery and radiotherapy on visual and endocrine function in nonfunctioning pituitary adenomas.

The effect of surgery alone or followed by radiotherapy in recovering visual abnormalities, debulking tumor mass and restoring hormone impairments was evaluated in 84 patients with clinical nonfunctioning pituitary adenomas (NFPA) subjected to 1-10 yr follow-up. All patients underwent surgery via transsphenoidal (in 69) or transcranic-pterional approach (in 15). Radiotherapy was performed after surgery in 59 of 72 patients with incomplete tumor removal. The assessment of pituitary function was performed in all patients before and every 1-2 yr after surgery and/or radiotherapy. Radiological and ophthalmologic assessment was performed before and 3, 6 and 12 months after surgery, then yearly. At diagnosis, headache and visual disturbances occurred in 63 and 58 patients, respectively, while deficiency of GH, TSH, ACTH, FSH, LH and ADH was documented in 55, 7, 19 47 and 6 patients, respectively. After surgery, gonadal function recovered in 12 women, visual disturbances improved in 43 patients (15 regained normal vision), pituitary function improved in 8 of 62 patients, worsened in 34 patients. At MRI, complete tumor removal was documented in 12 of 84 patients. After surgery alone, tumor regrowth was observed in 7 patients between 3-7 yr. After radiotherapy, vision improved in 9, remained unchanged in 49 and worsened in 1 of 59 patients. After radiotherapy, tumor regrowth was documented in 9 patients between 2-12 yr and the prevalence of hypopituitarism raised from 28.8% to 92% after 1 and 10 yr. In conclusion, surgery alone is effective only in a minority of patients (14.3%) and radiotherapy causes hypopituitarism in rather the totality of patients after 10 yr. The prevalence of tumor regrowth was similar in irradiated ones (15%) and non irradiated patients (28%; chi(2), p = 0.4). Therefore, a careful radiological followup is suggested after surgery so that radiotherapy can be performed promptly on the basis of clinical data, tumor regrowth and/or invasiveness documented at histology.

Adenoma↗

PubMed2006

Tuberculum sellae meningiomas: functional outcome in a consecutive series treated microsurgically.

OBJECTIVE: The objective of this study was to analyze a series of patients harboring a tuberculum sellae meningioma with regard to clinical presentation and long-term functional outcome. METHODS: Data in a consecutive series of 62 patients harboring a tuberculum sellae meningioma treated microsurgically between 1990 and 2003 were retrospectively reviewed. RESULTS: The mean age of the 46 women and 16 men enrolled in the study was 53 years (range = 29-81 years). The presenting symptom was visual compromise in 87.1% of the patients, and examination revealed decreased visual acuity in 79% and impaired visual fields in 64.5% of the patients. In addition, 14.5% of the patients had preoperative hormonal abnormalities. Simpson grades I and II resections, usually via a pterional approach, were achieved in 90.3% of the patients. Postoperatively, vision improved in 53.2%, remained unchanged in 29.8%, and deteriorated in 17.0% of the patients. The intraoperative finding predicting an unfavorable visual outcome was a thin atrophic optic nerve, encasement of the nerve, or tumor adhesion to its undersurface. Of the patients, 12.9% required permanent postoperative hormonal replacement. After a mean follow-up period of 6.0 years (range = 18 months-14 years), 88.7% of the patients resumed normal life activity and 2 recurrent tumors were observed (3.2%) and reoperated. CONCLUSIONS: Preoperative magnetic resonance imaging provides reliable information with regard to dislocation of critical vascular structures. However, the relationship between optic nerves and tumors (eg, adhesion and encasement) affected postoperative results and can only be fully appreciated during microsurgery. Visual outcome may be improved by preserving the microvasculature supplying the optic apparatus.

Adult↗

PubMed1998

A neural model of binocular integration and rivalry based on the coordination of action-potential timing in primary visual cortex.

In normal vision, the inputs from the two eyes are integrated into a single percept. When dissimilar images are presented to the two eyes, however, they compete for perceptual dominance, so that one eye's view suppresses that of the other. Recent evidence suggests that this phenomenon, known as binocular rivalry, arises through competition between alternative stimulus interpretations in extrastriate cortex. Because eye-specific information appears to be lost at this stage, it remains unclear how the stimulus conditions that yield binocular rivalry are distinguished from those that produce stable single vision. Using a neural network that models the mammalian early visual system, I investigate here the hypothesis that congruent and conflicting stimuli are distinguished by their different effects on the relative timing of action potentials in primary visual cortex (V1), where monocular inputs are first combined. In the model, congruent stimulation of both eyes results in synchronization of discharges among binocular neurons in V1. By contrast, conflicting stimulation of the two eyes results in neuronal asynchrony in this area. This asynchrony then produces rivalrous response suppression at later stages in the visual pathway. Synchronization of firing in V1, however, prevents such competition, thereby ensuring non-rivalrous responses. These novel effects of spike timing on competition emerge naturally from the network dynamics. The results suggest that input-related differences in relative spike timing at an early stage of visual processing may play an important part in the phenomena both of binocular integration and rivalry; furthermore, they indicate that the temporal patterning of cortical activity may be a fundamental mechanism of selection among competing stimulus representations.

Action Potentials↗

PubMed1998

Suprasellar meningiomas--neurological and visual outcome at long-term follow-up in a homogeneous series of patients treated microsurgically.

Most of the previously published surgical series of suprasellar meningiomas have two disadvantages: (1) patients involved were treated within a relatively long time period, making analysis more difficult, (2) radiographic long term follow-up examinations with either CT- or MRI-scans were not performed. Both disadvantages were overcome in our retrospective clinical study, consisting of 50 consecutive patients with suprasellar meningiomas treated between 1982 and 1991. Radiological, ophthalmological, and neurological investigations were performed preoperatively, postoperatively and at long term follow-up (mean: 5.7 years). A radiologically confirmed radical tumour removal could be achieved in 84% of patients. Both, the peri-operative mortality (2%) and serious operative morbidity (6%) were low. However, 12% of patients developed late onset epilepsy. At long term follow-up, visual function was improved in 67%, unchanged in 9% and worsened in 24%. In more than 50% of patients the vision showed recovery over a longer time period than the first 10 days after operation. Radiographic control examinations revealed tumour recurrences in 2 patients (both asymptomatic) and progress of residual tumour in 5 patients (2 symptomatic, 3 asymptomatic). Since introduction of modern neurosurgery, a clear improvement in the surgical treatment of suprasellar meningiomas can be observed. However, the still long delay in diagnosing these tumours correctly prevents a further improvement of the ophthalmological results at long-term follow-up. Due to a relatively high rate of late onset epilepsy, anticonvulsive prophylaxis for 6 months seems to be justified. Regarding present preoperative diagnostic measures, ia-DSA seems only be indicated in patients with CT/MRI-scans, suspicious for tumourous narrowing or invasion of major cerebral arteries. In addition, we recommend radiographic control examinations at regular time intervals to confirm radical tumour removal and to detect the "ideal" point of time for renewed treatment.

Adult↗

PubMed2003

Craniopharyngioma: a review of long-term visual outcome.

PURPOSE: To assess the clinical presentation and long-term visual outcome in a series of patients with craniopharyn-gioma. METHODS: Retrospective case review. RESULTS: Thirty-six patients were reviewed, comprising 19 female patients and 17 male patients. The age range was 2-77 years with a bimodal distribution of 17 children (mean age 10 years) and 19 adults (mean age 47 years). Blurred vision was the most common visual complaint (23 cases, 64%) and headache the most frequent systemic complaint (19 cases, 53%). The average duration of systemic symptoms was 45 weeks compared to 10 weeks for visual symptoms. Deficits in visual acuity occurred in 13 patients (36%) and showed no significant change from initial presentation to final review. Sixteen patients (44%) had bitemporal hemianopia on presentation and pleomorphism (change from one type of visual field defect to another) occurred in 11 patients. Recurrence of tumour occurred in 15 patients (42%) and was more likely in children (59%) than adults (26%). The mean time period to recurrence was 7 years. The average follow-up period for all cases was 10 years. CONCLUSION: Patients with craniopharyngioma generally present late, and the visual symptoms are often preceded by a long history of systemic symptoms. Children are more likely to present with systemic symptoms than adults. Visual field pleomorphism is a feature of craniopharyngioma and occurred in one-third of the patients. Local recurrence is common. Although magnetic resonance imaging is the recommended means of follow up, regular neuro-ophthalmic review is useful in the early detection of anterior visual pathway compression by recurrent tumour.

Adolescent↗

PubMed2006

Endoscopic transnasal orbital decompression for visual failure due to sphenoid wing meningioma.

AIM: To review a group of patients with sphenoid wing meningioma and visual impairment. The technique and results for endoscopic transnasal decompression of the orbital apex is presented. PATIENTS AND METHODS: Patients presenting between 1993 and 2004 with visual impairment due to sphenoid wing meningioma were identified. All patients had full ophthalmic assessment, automated visual field testing, and appropriate orbital imaging. Patients with clinical evidence of significant progression in visual impairment (loss of acuity, reduced colour discrimination, or field deterioration) underwent endoscopic transnasal orbital decompression. OUTCOME MEASURES: Assessment of visual function (Snellen acuity, Ishihara colour perception, and visual field testing), together with other measures of orbital structure and function (ocular balance, ductions, and exophthalmometry). RESULTS: Twelve patients (all women) presented to the Orbital Clinic between the ages of 38 and 71 years (mean 42.6; median 48.5 years) and with symptoms for an average of 32 months (3-102 months; median 22). The most common symptom was swelling and proptosis, in 11 (91%) patients, and subjective deterioration of vision had been noted in six cases (50%). Eight right orbits (67%) were affected and the preoperative acuity varied between Snellen 6/5 and counting fingers, with visual field impairment in all cases. There was an average of 5.0 mm of axial proptosis (range 5-9 mm; median 5). Endoscopic decompression was without complication in all cases. With a follow-up interval of 33.9 months (range 5-80; median 26 months), there was a subjective and objective improvement in visual functions-with Snellen acuity improving between 1 and 4 lines in seven patients, reduction in relative afferent pupillary defect in 10/12 patients, and improved visual field testing. There was a 2.3 mm reduction in proptosis (1-4 mm; median 3 mm) with less lid swelling, improved ocular balance and motility in four patients, and slightly worse diplopia in one patient. Three patients required further procedures: one had ipsilateral middle meatal antrostomy for retained secretions at 18 months and two had strabismus surgery. Three patients underwent fractionated radiotherapy for large tumours, or for late tumour growth and recurrent visual impairment. CONCLUSION: Orbital decompression by transnasal endoscopic ethmoidectomy appears to alleviate optic nerve compression due to sphenoid wing meningioma, with a reasonable relief of the condition for some years. Some patients will require later radiotherapy for progressive tumour growth or visual failure.

Adult↗

PubMed1997

A prospective multicenter trial of octreotide in 24 patients with visual defects caused by nonfunctioning and gonadotropin-secreting pituitary adenomas. French Multicenter Octreotide Study Group.

OBJECTIVE: The somatostatin analog octreotide has been demonstrated to improve optic tract compression caused by pituitary macroadenomas within hours of its administration and/or reduce tumor size in some patients. We report the results of a prospective multicenter study of the effects of octreotide on visual function and tumor size in patients with nonfunctioning pituitary adenomas or gonadotropin-secreting adenomas. METHODS: Twenty-four patients with visual defects caused by histologically confirmed macroadenomas were administered octreotide via continuous subcutaneous infusion, as follows: 100 micrograms the 1st day and, if necessary, 200 micrograms the 2nd and then 100 or 200 micrograms three times daily if visual function improved. Vision was assessed after 4 days, 1 month, and 2 months, including tumor size evaluation. Visual improvement was defined by a net gain of at least 2/10 in acuity and/or of more than 20% of the surface of one isopter (a reduction in tumor volume of > or = 20% of the initial measurement); opposite changes were defined as deterioration. RESULTS: Visual improvement was noted in 13 of 24 patients, 10 of 23 patients and 9 of 22 patients, and was not noted in 11 of 24 patients, 14 of 23 patients, and 13 of 22 patients after 4 days, 1 month, and 2 months, respectively. After 2 months, three adenomas had shrunk, three had not changed in size, and one had increased; visual function improved in the seven patients with these adenomas. Octreotide was discontinued in 13 patients for lack of efficacy. CONCLUSION: The incidence of visual improvement and tumor shrinkage noted in this study was higher than previously reported. Our data suggest that early onset of visual improvement might help in deciding which patients profit from octreotide. However, concomitant gain in visual acuity with deterioration in visual fields or visual improvement with an increase (moderate) in tumor size can occur.

Adenoma↗