AUGENHEILKUNDE 214/1999 – ISSUE 5

Abstracts:

S. 260-262 (Art. 500)

Effects of naftidrofuryl (Praxilène®) on optic nerve head blood flow in glaucomatous patient
Farid Achache, Patrick Titzé, Armand Movaffaghy, André Mermoud

Purpose To evaluate the effects of an S2 specifique antiserotonine agent (Naftidrofuryl) on the optic nerve head blood flow in glaucomatous patient.

Patients and Method 11 glaucomatous subjects were enrolled in the study. After administration of 200 mg naftidrofuryl twice daily for 7 days: values of optic nerve head blood flow (Fonh), velocity and volume were recorded in the temporal rim and cup of the optic nerve head. Blood flow measurements were performed by laser doppler flowmetry at day 0 and day 7 before and one and two hours after drug administration.

Results Our study showed a significant improvement of perfusion pressure (pp0.02) at day 7 and an increase of mean ophthalmique artery pressure (pp0.03).

Discussion Our preliminary results on a small number of patients and a short follow-up indicate that the use of naftidrofuryl may enhance optic nerve head blood flow in glaucomatous patients. Further studies may confirm these results.

Key words Naftidrofuryl - optic nerve head blood flow - laser doppler flowmetry

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S. 263-265 (Art. 501)

Membrane-bound carbonic anhydrase (CA IV) in human corneal epi- and endothelium
Thomas J Wolfensberger, Isabelle Mahieu, Nicholas D Carter, Etienne Hollande, Matthias Böhnke

Purpose Active HCO3P transport through the corneal endothelial cell layer causes a dehydration of the corneal stroma and is thought to be driven by Na/K- and HCO3P-dependent ATPase as well as an electro-genic Na/HCO3P cotransport. Transmembrane bicarbonate transport has also been associated with the recently characterised membrane-anchored isoform of carbonic anhydrase (CA IV) in various tissues. We investigated the localisation of CA IV in human fresh and cultured epi- and endothelium at the light- (LM) and electronmicroscopic (EM) level.

Methods Postmortem corneas were obtained within 12 hours of death, stored in formaldehyde and sectioned in paraffin. LM immunohisto-chemistry was performed using the purified g-globulin fraction of a polyclonal chicken antibody against CA IV isolated from human kidneys. Epi- and endothelial cell cultures were grown in uncoated flasks under standard conditions and processed both for LM and EM immunohistochemistry using the same antibody.

Results Lightmicroscopy of fresh tissue showed membrane staining for CA IV in the whole circumference of the endothelium. Little staining was also observed in some cells of the basal cell layer of the epithelium. Immunohistochemical staining at the EM level was confined to the cell surface of confluent cultures of both epi- and endothelial cells.

Conclusion The localisation of CA IV to the cell surface of fresh and cultured corneal endothelium suggests the presence of a membrane-bound ion exchange mechanism which may be important for HCO3P transport and corneal hydration. Compromising this mechanism by treatment with local carbonicanhydrase inhibitors may be of clinical importance in selected endothelial disease.

Key words membrane-bound carbonic anhydrase - cornea - epithelium - endothelium

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S. 266-269 (Art. 502)

Color and morphological changes in the iris
Josef Wollensak

Background The high variability of iris structures can be used for diagnostic purposes.

Methods An overview of the numerous changes visible at the slit lamp and possible diagnosis.

Results Short description of possible irispathology with hints on pathology and treatment.

Key words Iris - forme - colour - tumors

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S. 270-271 (Art. 525)

Titrable intraoperative anesthesia and postoperative analgesia
Wido M. Budde, Jost B. Jonas, Thomas M. Hemmerling, Michael Dinkel

Purpose To evaluate a temporary retrobulbar catheter for local anesthesia in intraocular surgery and for postoperative analgesia after intraocular surgery.

Patients and Methods The study included 40 patients undergoing pars-plana vitrectomy (np24) or cyclocryocoagulation (np16). After a retrobulbar injection through a 23G neede, a commercially available 28G flexible catheter was inserted through the needle. As soon as the patients complained about pain during or up to 24 hours after surgery, local anesthetics were injected through the catheter.

Results Repetitive injections of anesthetics were necessary in 13 patients during pars plana vitrectomy. Starting about 2 hours after surgery, 13 patients after pars-plana vitrectomy and all patients who had undergone cyclocryocoagulation received up to 6 re-injections (every 1.5-5 hours). After all re-injections, the patients became pain-free within two minutes. The catheter was removed after 24 hours.

Conclusions The results suggest that a temporary insertion of a catheter into the retrobulbar space allows repetitive application of local anesthetics thus leading to a titrable local anesthesia and postoperative analgesia in intraocular surgery.

Key words Local anesthesia - Intraocular surgery - Catheter

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S. 272-274 (Art. 503)

Mechanical ocular pulsatile-flow model to challenge the 'Ocular Blood Flow' (O.B.F.)-Device with known pulsatile-flow values
Phillip Hendrickson

Background Ocular perfusion consists of steady-state and pulsatile components of flow. The latter can be measured clinically by means of the 'Ocular Blood Flow'(OBF)-device (O.B.F. Ltd, Crowshearst, GB).

Methods 1) Mechanical 'eye': To mechanically simulate the effect of pulsatile flow in the eye, a mechanical 'eye' model was built: A brass chamber (9 cm3) was machined and fitted with in- and outflow connections. The front opening was covered with a taughtly fixed rubber membrane (COSANO, no. 5203.106, Migros AG, Zurich) which, as mechanical 'cornea', pulsated with changes in pressure within the mechanical chamber.
2) Mechanical 'heart': To mechanically simulate pulsatile flow (i.e. pulsations in pressure like those within the human eye), two reservoirs were constructed of acrylic plastic and mounted on an upright optical bench with a millimeter scale. The reservoirs were constantly filled to overflowing with perfusate (tap water) and were connected by rubber tubing to the 'eye'-chamber. A computer-guided valve alternated between the 'systolic' and 'diastolic' columns of different, independently adjustable elevation. Frequency and duration of each pressure phase could also be independently adjusted via dialog with the computer. Input pressure levels were measured just outside the input using a transducer. The OBF-device measured the chamber pressure at the center of the rubber 'cornea'.

Results Even the slightest alterations in the parameters (frequency, amplitude, and pressure) were precisely detected by the OBF-device, both graphically and numerically.

Conclusions Challenged by the mechanical model, the OBF-device demonstrated high sensitivity and fidelity of reproduction of any and all pulsations in intra-"ocular"-pressure.

Key words Model-'Eye' - OBF-device - pulsatile flow - intraocular pressure - mechanical 'heart'-model

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S. 275-276 (Art. 523)

Mechanical fundus-perfusion model: blood-flow velocity determined with Heidelberg Retina Flowmetry (HRF) and digital ICG-angiography (HRA)
Phillip Hendrickson, Therese DeMel, John C. Peterson

Background Heidelberg Retina Flowmetry (HRF) is now popularly, perhaps even indiscriminately applied in eye research, without apparent concern for the fact that the results are given numerically, but without physical units.

Methods 1) HRF: To challenge the HRF-device with known values of blood-flow velocity, a perfusion chamber with input and output connections was constructed of acrylic plastic. Three serial segments were milled to provide cross-sectional areas (1.93 mm2, 3.33 mm2, and 5.08 mm2) and accordingly decreasing, true, clinically representative flow-velocity values. Under a constant perfusion setting of a calibrated clinical infusion pump (Perfusor Secura FT, B. Braun Medical AG, Sempach, CH), heparinized human blood (P. H.) was pumped through the chamber, and the HRF-parameter, "VELOCITY" was measured within one image encompassing the three chamber segments, using a 20º!5º-field and a 20!20-pixel measuring "window".
2) HRA: Immediately thereafter, our perfusion model was placed in front of the Heidelberg Retina Angiography device, the infusion pump started at the same constant level, and a 1cc bolus of ICG dye was added to the blood. Digital ICG-angiography was then conducted, and the images analyzed on-screen.

Results In the three segments of the perfusion chamber, flow velocities determined ICG-angiographically were 11.5 mm/s, 6.7 mm/s, and 4.4 mm/s, respectively. The corresponding values for HRF-"VELOCITY" were 5.3, 4.2, and 3.4, respectively (no units).

Conclusions Under identical perfusion conditions, the phenomenologically (ICG-angiographically) determined values of flow velocity in the 3 perfusion chamber segments ran similar to (but not numerically coincidental with) those determined for HRF-parameter "VELOCITY". Extrapolation of HRF-values to true physical units is, thus, feasible.

Key words retinal-perfusion model - HRA - HRF - perfusion pump - angiography

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S. 277-279 (Art. 504)

Complications of surgery of epiretinal membranes
Guy Donati, Anastasios D. Kapetanios, Constantin J. Pournaras

Material and methods Preoperative findings, intraoperative and postoperative complications as final results of 70 consecutive cases of idiopathic or secondary ERM operated by the same retina surgeon were analyzed.

Results In all cases the ERMs were succesfully removed from the fovea. The mean v. a. increased from 0.34±0.2. to 0.54B0.31, (p < 0.05) postoperatively. Idiopathic and secondary ERMs both showed significant improvement after surgery. Complications included intraoperative hemorrhage and retinal tears. Postoperative progressive nuclear sclerosis, retinal tears causing detachments, macular edema and retinal pigmentary epitheliopathy.

Conclusions Performing surgery for ERMs is worthwhile on eyes with major decreased v. a. and on eyes with metamorphopsia but only moderately reduced vision. Postoperative complications are frequent but can usually be managed successfully. Of them only retinal detachment is of some worse prognosis on the final functional outcome.

Key words epiretinal membranes - surgery

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S. 280-281 (Art. 505)

NO donors and retinal branch vein occlusion
Guy Donati, Anastasius D. Kapetanios, Constantin J. Pournaras

Purpose The developement of extended territoires of nonperfused capillaries after branch vein occlusion (b.v.o.) is correlated to the secondary constriction of the arteriole crossing the occluded territory. Local NO release is impaired soon after b.v.o. and accounts for the secondary arteriolar constriction. In this report we present evidences showing that administration of an NO donor can reverse the secondary arteriolar vasoconstriction observed after b.v.o.

Material and methods Simultaneous preretinal NO profiles and arteriolar diameter measurements were performed in miniature pigs after experimental b.v.o. The effect of preretinal microinjections of the NO-donor Sodium Nitroprusside on the arteriolar diameter was studied.

Results A significant arteriolar vasoconstriction occurring in parallel with a preretinal [NO] decrease was observed 4 hours after b.v.o. Microinjection of the NO-donor SNP caused a segmental, reversible arteriolar dilatation.

Conclusion The present results, suggest that local NO supply in the first hours following b.v.o. may contribute to protect the retina against ischemic injury. (FNSRS n° 32-49543.96)

Key words NO-donors - branch vein occlusion

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S. 282-284 (Art. 506)

Results and complications of idiopathic macular holes surgery
Anastasios D. Kapetanios, Guy Donati, Constantin J. Pournaras

Aim of the study We conducted a retrospective study in order to evaluate the anatomical and functional outcomes of eyes with constituted idiopathic macular holes as well as the rate of peri and postoperative complications when patients are operated on by conventional surgery.

Material and methods Twenty-nine consecutive eyes (26 patients) presenting idiopathic macular holes (stage II or III) were included in the study. Conventional vitreous surgery with a three-port system and a careful peeling of the internal limiting membrane and/or an epiretinal membrane was performed. History, preoperative eye examination, operative findings, postoperative course and final examination were reviewed.

Results Anatomical closure was obtained in 76% of the cases after one operation and in 93% following additional operation. Cataract was the most frequent complication (71%). Peripheral iatrogenic, retinal tears were found in 14% of the cases perioperatively, and retinal pigment epithelial anomalies in 24% of the cases postoperatively.

Discussion Conventional surgery of the idiopathic macular holes with careful peeling of the internal limiting membrane and/or an epiretinal membrane is successful for the anatomic closure of the hole in most of the cases. Complications are without major incidence in the visual function.

Key words idiopathic macular holes - surgery - complications

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S. 285-287 (Art. 507)

Choroidal blood flow measured with a new confocal compact laser Doppler flowmeter
Martial H. Geiser, Charles E. Riva, Ulrich Diermann

A new instrument for the measurement of choroidal blood flow in the fovea is presented. It is based on the laser Doppler method and a confocal optical system with an indirect detection of the Doppler shifted light.

Method The intensity of the laser beam (785 nm) at the cornea is 90 µW. Measurements were obtained from a normal population of 21 subjects under resting conditions without dilating the pupil.

Results The reproducibility of the choroidal blood flow, based on 5 measurements of 10 s each in 5 randomly selected subjects, is 9%. The minimum detectable change for a statistical significance of p = 0.05, based on a population of 21 subjects and 10 s measurements, is 9%.

Conclusion This new compact instrument appears to be suitable for the investigation of the physiology and pharmacology of choroidal blood flow and the effect of age-related macular degeneration.

Key words choroidal circulation - laser Doppler flowmetry - confocal optics - fovea

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S. 288-290 (Art. 508)

Normative values for the mouse electroretinogram
Nicole Kueng-Hitz, Pascal Rol, Günter Niemeyer

Purpose The electroretinogram (ERG) is an appropriate method to evaluate the retinal function in a variety of animal models. In this study we present suitable conditions of stimulation and recording in the dark-adapted mouse.

Methods Mice (np15) were dark-adapted during 14 hours and anesthetized with a single intraperitoneal injection of xylazine/ketamine. Pupils were dilated and a d.c.-silk-silver electrode or a AgCl-contact-lense electrode was placed on the cornea. The electroretinogram (ERG) was obtained by Ganzfeld stimulation over a range of 6 log units of intensity (8!10P2 - 8!104 cd/m2). Intensity, duration and the intervall of the light stimuli were varied separately.

Results Reproducible values of the intensity-response functions are obtained for the a-, b- and c-waves of the ERG under well controlled adaptation- and stimulus-conditions. C-wave amplitudes are best evaluated using d.c.-recording and a stimulus duration of 4 seconds. The position of the d.c.-silk-silver electrode on the cornea can affect the ERG-amplitudes. Using a contact-lense electrode, the recorded b-wave amplitudes are on average 20% below those recorded with a centrally positioned d.c.-silk-silver electrode. Stimulus-intervalls of at least 60seconds are recommended at high intensities.

Conclusions An unequivocal assessment of retinal function requires reproducible ERG-values over a wide range of intensities. To obtain these, well controlled and standardized experimental conditions are required.

Key words electroretinogram - mouse - retina

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S. 291-294 (Art. 510)

Central corneal pathologies
Beatrice E. Frueh

Background Central corneal pathologies can lead to an irreversible decrease of best corrected visual acuity if not diagnosed and treated appropriately. This article reviews the differential diagnosis of central corneal opacities in the newborn, of central infectious corneal ulcers, and the therapy of sterile, central keratolysis.

Material and methods Authors' personal experience and review of the literature.

Results Flow charts for diagnosis and treatment strategy have been elaborated.

Conclusions Corneal opacities in newborns create an emergency situation. In order to treat successfully and avoid or diminish amblyopia, it is imperative to rule out congenital glaucoma. The aetiology of central corneal ulcers should always be confirmed by positive cultures to be able to treat specifically. When the standard topic therapy fails, one has to consider rare bacteria, parasites, virus, or patients' compliance. The treatment of central sterile keratolysis in rheumatoid arthritis must be intensive and immunosuppression has to be performed early enough in the course to prevent the formation of a descemetocoele or spontaneous corneal perforation.

Key words cornea - congenital - ulcer - acanthamoeba - keratitis - rheumatoid arthritis

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S. 295-299 (Art. 511)

Examination of the optic disc and nerve fiber layer in glaucoma
Daniel S. Mojon, André Mermoud

Background For diagnosis and follow-up of glaucoma an exact evaluation of the optic nerve disc and the nerve fiber layer is necessary.

Methods The slit-lamp evaluation of the optic nerve disc and nerve fiber layer is presented as well as the evaluation with the Nerve Fiber Analyzer and the Heidelberg Retina Tomograph.

Results Signs of a glaucomatous optic disc include a difference of more than 0.2 in the vertical cup to disc (CD) ratio between the eyes, a vertical CD ratio exceeding more than 0.1 the horizontal, larger CD ratios in small optic discs, notching of the neuroretinal rim, an enlarged zone beta of parapapillary chorioretinal atrophy, and peripapillary hemorrhages. Atrophy of the nerve fiber layer may be localized or diffuse. Both types of atrophy may be present at the same time.

Conclusions Knowledge of all signs of the glaucomatous optic disc and forms of nerve fiber layer atrophy allows an earlier diagnosis of glaucoma and an earlier recognition of progression.

Key words optic disc - nerve fiber layer - glaucoma - examination techniques - Nerve Fiber Analyzer - Heidelberg Retina Tomograph

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S. 300-301 (Art. 512)

Position of the central vessel trunk and parapapillary atrophy
Wido M. Budde, Jost B. Jonas, János Németh, Anselm E. Gründler

Purpose To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the location of parapapillary atrophy in glaucoma.

Methods Color stereo optic disc photographs of 79 patients with primary or secondary open-angle glaucoma and 53 normal subjects were morphometrically evaluated. We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of parapapillary atrophy in four 90° quadrants.

Results After correction for normal values, the beta zone area of parapapillary atrophy in the glaucoma eyes was significantly larger, when measured in the disc quadrant most distant to the central retinal vessel trunk exit than as if measured in the quadrant containing the vessel trunk exit.

Conclusions Position of the central retinal vessel trunk exit on the lamina cribrosa influences the location of parapapillary atrophy in glaucoma. The longer the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy.

Key words Open-angle glaucoma - parapapillary atrophy

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S. 302-304 (Art. 513)

Effect of a decreased ocular perfusion pressure on iris blood flow measured with laser Doppler flowmetry
Stéphane R. Chamot, Armand Movaffaghy, Benno L. Petrig, Charles E. Riva

Purpose To determine whether iris blood flow (IBF) is regulated in response to an acute decrease in mean ocular perfusion pressure (PPm=MOAP-IOP, MOAP=mean ophthalmic arterial pressure) induced by increasing the intraocular pressure (IOP).

Methods Iris blood flow was measured using a slit lamp incorporating a laser Doppler flowmetry (LDF) module. The study was conducted on 12 normal volunteers (14 to 59 years old). IOP was raised using a scleral suction cup. In Exp. #1, the suction pressure was successively raised in steps of 50 to 100 mm Hg, each lasting about 10 sec, until IOP reached the MOAP level. In Exp. #2, the suction was raised to 200 mm Hg in 4 successive steps of 2 min duration.

Results In Exp. #1, no significant change of IBF was observed for small decreases of PPm (< 23%); greater decreases of PPm resulted in a linear IBF decrease (p < 0.01). In Exp. #2, such a IBF versus PPm decrease was also observed (p < 0.001). Immediately after release of suction, a significant, transient IBF increase of 79% above baseline level was observed.

Conclusion These results suggest that some IBF regulation occurs for small PPm decreases (< 23%); no IBF compensatory mechanism appears to operate for further decreases of PPm (> 23%).

Key words Laser doppler flowmetry - blood flow - iris - intraocular pressure - regulation - hyperaemia

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S. 305-310 (Art. 514)

Diseases of the vitreoretinal interface
Fritz Koerner, Justus Garweg

Background A pathological vitreomacular adhesion is a common pathogenetic mechanism of various clinical entities such as idiopathic epimacular membrane, vitreomacular traction syndrome, and macular hole. Vitrectomy is recommended for these disorders. Anatomical and functional results in 207 operated eyes are discussed.

Patients and methods The results of a vitrectomy in 3 groups of patients were compared: idiopathic epimacular membrane (group 1, np52), vitreomacular traction syndrome (group 2, np48); macular hole (group 3, np107; 33 eyes without and 74 eyes with retinal detachment). After excision of the vitreous gel, a thin layer of epimacular vitreous cortex was identified and excised by gentle aspiration under continuous air infusion. In 50 of the 107 eyes of group 3, the vitrectomy was combined with the application of a drop of autologous blood to the macular hole.

Results A vitreomacular adhesion existed in 56% of group 1, 74% of group 2, and 84% of group 3. The visual acuity improved in 54%, 62% and 50% of eyes of the 3 groups, respectively. More eyes with an initial visual acuity of at least 40/200 achieved final vision of 80/200 or better (57%, 65% and 48% of group 1 to 3, respectively) than eyes with acuities of less than 80/200. A postoperative cataract was the main reason for reduced visual results in all cases. In group 3-eyes with retinal detachment and/or myopia, a significant postoperative visual improvement was achieved only after application of autologous blood to the macular hole.

Conclusion A pathological vitreomacular adhesion was identified in the majority of patients with idiopathic epimacular membranes, vitreomacular traction syndrome, and macular hole, respectively. Vitreoretinal surgery for syndromes with vitreomacular traction is indicated as it warrants a significant improvement of visual function and relief of metamorphopsia.

Key words Epimacular membrane - macular hole - posterior vitreous detachment - vitrectomy - vitreomacular traction syndrome

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S. 311-316 (Art. 515)

Macular edema: symptoms and diagnosis
Peter Bischoff

Background In this study, the "Macular edema" syndrome is examined in detail from the symptoms right through to the diagnosis. The 9 most important differential diagnoses are also listed, as well as a summary of the currently applicable therapy recommendations.

Material and methods This overview is based on existing literature as well as own case studies.

Results

  • The symptoms of macular edema consist of visual acuity deterioration, micropsy, metamorphopsy, reduced colour perception, as well as central or paracentral scotoma.
  • Ophthalmologist checks should include a case history (age, diabetes, hypertonia, allergies, cataract surgery?), a detailed examination of the fundus, if possible with a slit-lamp and a contact or non-contact lens, whereby one must pay attention here to the swelling of the retina as well as the presence of hard exsudates in the macular region. It is important to use fluorescence angiography in this case, to achieve a correct differential diagnosis, and eventually for treatment. This angiography may equally reveal a capillary leakage, a cystoid macular edema, a leaking point or a choroidal neovascularization.
  • The differential diagnosis can be divided into the following commonly-occurring groups: age-related macular degeneration/macular edema after a branch or central retinal vein thrombosis/central serous chorioretinopathy/Irvine-Gass syndrome after cataract operation/uveitis/epiretinal fibroplasia/juxtafoveal retinal teleangiectasis and tumors (choroidal melanoma, metastasis and hemangioma).
  • Treatment: Apart from the seldomly applicable causal therapy, the following treatments can be used: laser photocoagulation, anti-inflammatory and rinse medication, and in some cases vitrectomy as well as a low dosage of radiation therapy.

    Conclusions In the case of macular edema the ophthalmologist's responsability is to perform a differential diagnosis and recommend appropriate and sensible methods or treatment.

    Key words Fluorescence angiography - differential diagnosis - age-related macular degeneration - choroidal neovascularization - diabetic maculopathy - laser photocoagulation

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S. 317-320 (Art. 516)

Effect of highly active antiretroviral therapy (HAART) on cytomegalovirus retinitis
Yan Guex-Crosier

Aim A patient was till now considered at high risk of developping a cytomegalovirus retinitis when the CD4+ cells were under 100/mm3. The risk was major when the CD4+ were under 50/mm3. With the onset of a Highly Active Antiretroviral Therapy (HAART) the follow-up of AIDS patients has changed. The introduction of a HAART is associated with an increase in CD4+ cells. The aim of the study was to highlight clinical modifications of classical AIDS associated ocular diseases.

Materials and methods clinical observations will be correlated to recent data published in literature.

Results An immune response can be present against opportunitic infections. Cytomegalovirus retinitis can present an atypical pattern: The host immune response can be responsible for an increase of ocular inflammation, a hypopyon can even be seen. An intense vitritis can be present and frosted angiitis syndrome can be observed. A severe macular edema can be present and has to be treated with posterior sub-Tenon's steroid injections.

Conclusion with the restoration of an immune response under HAART therapy, clincial manifestation of AIDS associated ocular diseases has changed and the differential diagnosis of ocular lesions must include endogenous uveitis.

Key words AIDS - HAART - highly active antiretroviral therapy - cytomegalovirus retinitis - frosted angiitis syndrome - hypopyon - inflammation - uveitis

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S. 321-323 (Art. 522)

Entoptic imagery and potential visual acuity
Stavros A. Dimitrakos

Review of preoperative evaluation of visual function In the presence of media opacities, the prevision of the potential postoperative visual acuity constitutes often a complicate diagnostic problem. Its solution requires the experience of the ophthalmologist, who should take into account various elements from the patient's visual aggravation progress, the dissociation between far and near vision under mesopic and scotopic conditions, the actual grating acuity and the eventual hand movement- and light-perception, as well as, elements from the patient's objective examination, i.e., from the biomicroscopy with direct and indirect illumination through the still transparent media and from the binocular ophthalmoscopy of the fundus.

Methods reviewed Purkinje figure and luminous darting points visualization.

Possible predictions Light induced entoptic imagery, as Purkinje figure and luminous darting points, visualization, helps as a supplementary diagnostic procedure, for the prevision of a low, but socially useful postoperative visual acuity.

Key words entoptic imagery - opaque media - potential visual acuity

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S. 324-327 (Art. 509)

Visual hallucinations or illusions
François-Xavier Borruat

Introduction Visual hallucinations or illusions are not a rare symptom. However, they are often unrecognized. Unawareness of the meaning of these symptoms often mislead both the patient and his physician.

Purpose To define and decribe the types of visual illusions and hallucinations which can be commonly encountered in neuro-ophthalmological practice.

Methods Overview article.

Results Hallucinations are a perception not based on sensory input, whereas illusions are a misinterpretation of a correct sensory input. Both phenomenon can be due to medication or drug, or to an altered mental status. Visual hallucinations can be formed (objects, people) or unformed (light, geometric figures). They can be generated either by a lesion on the antechiasmatic pathway, by a seizure phenomenon, by a migrainous phenomenon, or by a release phenomenon secondary to visual deafferentiation. Investigations will be directed towards a retinopathy, an optic neuropathy, a chiasmal or retrochiasmal lesion, or a bilateral antechiasmal lesion (Charles Bonnet syndrome). Visual illusions include metamorphopsias, micro- macropsias, polyopia, palinopsia (visual perseveration), achromatopsia, Pulfrich phenomenon, or subjective vertical deviation. Illusions can be due to lesions of the retina, the optic nerve, the visual cortex (primary or associative), or the graviceptive pathways.

Conclusions As most patients do not spontaneously mention their symptoms, history taking is essential. The first step is to rule out medication or an altered mental status as the possible cause of these symptoms. Then, careful visual function examination should provide a good insight in the location of the lesion.

Key words Visual halluzination - visual illusion - Charles Bonnet syndrome

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S. 328-331 (Art. 521)

From symptoms to ERG-diagnosis
Günter Niemeyer

Retinal function can be documented noninvasively and objectively by electroretinography, complementing clinical examinations. Symptoms of nightblindness and of dayblindness with photoaversion, nystagmus, poor vision in infants or unclear visual field defects are meaningful indications for ERG testing. We use standardized (ISCEV) full-field single flash ERGs to evaluate the function of the rod- and of the cone-system. In infants, general anesthesia is useful to combine an abbreviated ERG protocol with ophthalmoscopy and fundus photography.

ERG testing facilitates to distinguish between functional deficits in the rod- and cone-system, between congenital-stationary retinal dysfunction and progressive retinal heredo-degenerations. Frequently a functional deficit of the retina without ophthalmoscopic changes can be assessed. These entities include achromatopsia, congenital stationary night blindness, early stages of retinitis pigmentosa (RP) or progressive cone dystrophy, as well as toxic retinal changes. Congenital amaurosis Leber (LCA), infantile RP, Usher's syndrome and retinal involvement in other neuropediatric or metabolic syndromes can be diagnosed or excluded by ERG recording early-on. Synoptic evaluation of the full-field ERG, pattern-ERG and VEP completes neuro-ophthalmological screening.

Key words ERG - electroretinography - retinal degeneration - night blindness

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S. 332-335 (Art. 517)

Leukocoria in the child: urgency and challenge
Aubin Balmer, Francis Munier

Purpose To heighten the awareness of the medical world to the importance of correct and rapid diagnosis in the presence of leukocoria in the child.

Methods Starting with the presenting symptom, the authors present the guide lines to follow in a practical manner in order to reach a diagnosis in the principal retinal diseases causing leukocoria.

Results A white pupil is due to retinoblastoma in almost half of all cases. Other possible causes, in order of frequency, are: persistent hyperplastic primary vitreous, Coats' disease, ocular toxocariasis, retinopathy of prematurity, retinal hamartomas. Diagnosis can usually readily be made by ophthalmoscopy, but may be problematic when the clinical presentation is atypical or in the presence of late complications. Age, sex, laterality, heredity, and in particular the presence or absence of calcifications and the size of the globe, are the main criteria for diagnosis. Ultrasonography plays a major role in this essential quest for correct diagnosis, quest which may ultimately lead to enucleation.

Conclusion Leukocoria in the child is a danger signal demanding certain diagnosis within the shortest possible time.

Key words Leukocoria - retinoblastoma - pseudoretinoblastomas

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S. 336-339 (Art. 518)

Ophthalmological examination of the infant
Corina Klaeger-Manzanell

Background The examination of the infant needs patience, special knowledge and skills to get to a reliable judgment of the visual functions of the child. For the practitioner it is important to rely on clinical methods without the apparatus reserved to ophthalmologic institutions.

Methods Based on the literature and personal experience the clinical examination techniques for infants are presented and the results are discussed with respect to the possible diagnosis.

Conclusion Simple clinical tests reveal most symptoms in the infant. Electrophysiological tests and imaging procedures are sometimes necessary.

Key words amblyopia - strabismus - nystagmus - examination - infant - visual impairment - pupillary response

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S. 340-345 (Art. 519)

Concomitant strabismus: from squint to squint syndromes
André Roth

Purpose To show how to progress from the deviation of the visual axis (provided the diagnosis of concomitant strabismus is certain) to the classification of the squint in one out of the different squint syndromes and consequently to adopt the appropriate therapeutic strategy.

Method Every sign correlated with the deviation contributes to progress step by step to the diagnosis of a given squint syndrome.

I The age on onset of strabismus, either convergent or divergent, and its characteristic, intermittent or constant, allow in a first step to evaluate the potential binocularity, as well in early as late (acquired) strabismus.

I The first group of early strabismus includes manifest infantile strabismus and microstrabismus. Both have abnormal binocularity. The possibility of functional amblyopia, angle variablilty and additional incomitances have to be investigated. Early intermittent strabismus keeping a potential normal binocularity are seldom.

I In the second group of late onset strabismus, retinal correspondance has to be investigated by correspondance tests and prism or bifocus compensation to distinguish between the two possible types (including the accommodative forms of strabismus), i.e. decompensated microstrabismus with abnormal binocularity or normosensorial strabismus with potential normal binoculaitity. In some cases potential binocularity may be initially uncertain and/or remain later on subnormal.

Result As the result of this systematic approach, every cases of squint can be classified in one out of the different squint syndromes. Based on the precise diagnosis, the appropriate treatment can be carried out. The goals of treatment which can be reached in every syndrome are indicated.

Discussion For an overall view of the squint symdromes a classification with two entrances are necessary, on the one hand early or late onset, on the other hand normal or abnormal binocular conditions.

Conclusion This approach of concomitant strabismus should serve as guide lines for clinical practice.

Key words concomitant strabismus - diagnostic stages - classification

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S. 346-350 (Art. 520)

Diplopia, from the symptom to the diagnosis
Hedwig J. Kaiser

Background This overview gives a rough frame how to proceede to a quick diagnosis and possible differential diagnosis in patients with diplopia.

Method A thourough interview concerning the onset of symptoms, invariability, and subjective perception is mandatory. The first step before examining ocular motility is to verify monocular or binocular double vision. When the reported diplopia is binocular, the examiner can carry out the red-glas test to determine the site of the double image. In a next step monocular range of movement in the 9 directions of gaze is evaluated to search for incomitance.

Results The main causes of diplopia are palsies of the oculomotor nerves, mechanical restriction - posttraumatic or inflammatory -, supranuclear lesions and disturbed neuromuscular junction.

Conclusion With a simple and clear diagnostic diagram ist is easy to work out the underlying cause of diplopia.

Key words Diplopia - cover-test - forced duction test - oculomotor nerve palsies - supranuclear motility disorders - mechanical restriction

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S. 351-356 (Art. 524)

60 years Alfred Vogt-Foundation, the prizewinners and their awarded works
Frank M. Sens, Balder P. Gloor

Background The Alfred Vogt-Prize is the highest award in Switzerland for scientific research in ophthalmology and related fields of research. The Alfred Vogt institution was founded 60 years ago in Zürich, where Alfred Vogt was working as the head of the department of Ophthalmology of the University Hospital. For this reason the activity of the foundation was recongizied on the occasion of the annual meeting of the Swiss Ophthalmology Society in Zürich 1998.

Method and results The biographical notes of Alfred Vogt were compiled. The winners of the prize and their distinguished papers are listed below. During the 60 years since the establishment of the foundation the prize was rewarded to 53 researchers or research teams. The awards were divided among svereal researchers in those years when many outstanding papers were submitted. On the other hand in many years no award was given due to lack of award worthing research papers. 7 researchers received the prize more than once.

Conclusion The list of the winners of the Alfred Vogt-Prize reflects the history of the Swiss Ophthalmology. To a number of researchers the awards allowed them further research, which let to excellent contributions to international Ophthalmology.

Key words Alfred Vogt - Vogt award - research foundation - History of Ophthalmology - Swiss Ophthalmology

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