AUGENHEILKUNDE 214/1999 – ISSUE 1

Abstracts:

S. 02-11 (Art. 450)

Excitotoxicity and glaucoma
Christian K Vorwerk, Rita Naskar, Evan B Dreyer

Glaucoma can be defined as a disease in which one of the pathophysiological consequences of raised intra-ocular pressure is damage of the optic nerve, and subsequently the loss of retinal ganglion cells (RGCs). One of the main aims of modern glaucoma therapy is to alter the intraocular pressure, either surgically or pharmacologically. Recently it was shown that the vitreous of glaucoma patients contains increased levels of glutamate (27 µM as compared to 11 µM in controls). This concentration of glutamate is sufficient to induce retinal ganglion cell death. The rise in intraocular pressure is probably the initial insult, which enhances the increase or release of glutamate. Although the increase in intravitreal glutamate levels is an accompanying feature of glaucoma, it could contribute to the loss of retinal ganglion cells in humans itself. Therefore, despite efficient control of intra-ocular pressure, RGC's loss will continue resulting in further visual impairment, if the toxic effect of glutamate is not blocked. If it would be possible to understand the mechanism leading to excessive vitreous levels of glutamate in glaucoma or to block its toxic effects, then the resulting visual loss could be retarded. This review discusses various proposed mechanisms leading to intraocular glutamate toxicity and the role of neuroprotection in this disease. (Literature search by Medline).

Key words Glaucoma - retinal ganglion cells - glutamate - excitotoxicity - neuroprotection - retina - NMDA

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S. 12-21 (Art. 453)

Confocal microscopy in corneal dystrophies
Zacharias AR Sherif, Uwe Pleyer, P Rieck, Christian Hartmann

Background Confocal microscopy represents a methodology that allows in vivo examination of corneal morphology, particularly of the epithelium and stroma.

Material and Methods Using the confocal microscope "ConfoScan Modell P2" epithelial, stromal and endothelial changes were evaluated in 11 patients with corneal dystrophies. All findings were compared with data from healthy individuals.

Results Confocal images could be correlated to conventional (slitlamp) biomicroscopic findings in all patients with corneal dystrophies. In addition, confocal microscopy provided more detailed images particularly of epithelial and stromal changes.

Conclusion Our data indicate that confocal microscopy provides information on living tissue that correlates with that obtained with conventional techniques on fixed and sectioned tissue.

Key words confocal microscopy - corneal dystrophies - in vivo observation

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S. 22-26 (Art. 447)

Prevalence of systemic and ocular diseases in age-related cataract patients
Christoph W Spraul, Martha J Jakobczyk-Zmija, Mark F Tobis, Gerhard K Lang

Background Cataract patients often display concomitant ocular and systemic diseases which may influence the decision between general and regional anesthesia. The aim of this study was to quantify co-morbidity of these patients and assess the influence of the two types of anesthesia an the anesthesiological risk on the frequency of intra- and postoperative complications and visual outcome.

Methods In this prospective study, in patients scheduled for cataract extraction at the University Eye Hospital and Clinic of Ulm (tertiary eye care center) all systemic and ocular diseases as well as intra- and postoperative complications were analyzed. The prevalence of the co-morbidity in our patients was compared to other studies including age-matched controls. The anesthesiological risk was quantified using the classification scheme of the American Society of Anesthesiologists (ASA).

Results Eighty-eight patients with a mean age of 70.4B11.7 years were analyzed. Sixty-one% of patients displayed systemic as well as ocular co-morbidity. Only systemic or ocular comorbidity was present in 32% and 5% of patients, respectively. Two% of patients exhibited neither ocular nor systemic comorbidity. In 61% of patients the surgery was performed in regional anesthesia and in 39% in general anesthesia. The prevalence of systemic and ocular co-morbidity as found in our study was significantly higher as compared to that in the general population of the same age. Visual improvement and the frequency of intra- and postoperative complications were independent on type of anesthesia and anesthesiological risk.

Conclusions Patients who were scheduled at our institution for cataract surgery exhibited a high frequency of ocular as well as systemic co-morbidity. This can be interpreted in such a way that patients with a high level of co-morbidity are referred to tertiary eye care centers for cataract surgery.

Key words Cataract - general anesthesia - phacoemulsification - prevalence - regional anesthesia - risk factors

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S. 27-30 (Art. 451)

Severe ocular injuries due to fishing equipment
Alexander A Bialasiewicz, Bettina Fuisting, Rüdiger Schwartz, Gisbert Richard

Background Severe ocular injuries due to fishing equipment are rare, almost exclusively involve the anterior segments of men, and bear a bad prognosis. We report on two men and one woman with different etiologies of accidents.

Patients In two men (53 and 39 yrs. OD and OS) and one woman (27 yrs., OD) a choroidal rupture due to a lead weight and subsequent choroidal neovascularisation (1!), temporal and nasal scleral and retinal lacerations (2!) due to a fish pick and a fish hook were noted. A laceration of the m. rectus int. (1!), uveal and retinal prolapse (1!), traumatic aniridia and aphakia (1!), a 12 and a 15 mm corneoscleral perforation temporal and nasal resp. including a retinal incarceration, a giant retinal tear 270°, and vitreous and subretinal hemorrhage were seen.

Surgery Interventions included 2! tight wound closure, 3! ppv, retinotomies (1!) endolasercoagulation (3!), silicone oil instillation (3!), muscel refixation (1!), and posterior lens implantation (1!). Subsequent surgery were silicone oil removal (2!) and membrane peeling (1!).

Results An anatomical reconstruction was achieved in all of the patients, and the best postoperative visual acuity was gained after 4-6 months (c6.0 sph (2!)p0.5, and c4.0 sph (1!)p0.3). Silicone oil was removed after 4 and 13 months resp. followed by hypotony and redetachments, in one patient with silicone oil in place vision remained stable for > 2 years up to now at 0.5.

Conclusions Accidents due to fishing equipment may result in lacerations and contusions and involve women as well as. Surgery for extensive lacerations and complications of choroidal ruptures may not be hopeless, however, the prognosis for subsequent interventions is not good. Indications to remove silicone oil in eyes bearing a relative ciliary body insufficiency due to a long-standing insufficient wound closure should be done very cautiously.

Key words fish hook - fish pick - injury - vitrectomy - silicone oil

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S. 31-36 (Art. 449)

Anisomyopia and myelinated nerve fibers - a syndrome
Helmut Höh, Barbara Käsmann-Kellner, Klaus-Wilhelm Ruprecht

Background The combination of anisomyopia and myelinated nerve fibres of the higher myopic eye is often correlated with a deep and therapy-refractive amblyopia. As the cause for the entity anisomyopia/myelinated nerve fibres a disorder of development on the level of the lamina cribrosa during embryo genesis has been suggested in the literature. There are only very few reports on a successful therapy of the amblyopia that goes along with anisomyopia/myelinated nerve fibres.

Patients We report on six patients, aged 6 to 28 years, who presented with anisomyopia, myelinated nerve fibres and deep amblyopia in the higher myopic eye. The four younger patients were enrolled into a therapeutic trial with contact lens correction and occlusion.

Results The six patients presented with varying degrees of anisomyopia between P3.5 D and P18.5 D. In addition, in two patients we found a microstrabism and in three patients an exotropia. In spite of consistent occlusion and full optical correction in the four patients who underwent therapy visual acuity did not improve to more than 0.4 (1! microstrabism, 2! exotropia, 1! no squint - best visual recovery in the patient with microstrabism).

Conclusions The combination of unilateral high myopia and myelinated nerve fibres represents a special entity which usually is correlated with a deep amblyopia. The amblyopia is nearly refractive to therapy even under consequent therapy with contact lenses and prolonged occlusion. Nevertheless one should try to treat the amblyopia to achieve at least a small improvement. The goal is to diagnose this constellation already in the first two years of life. As our cases show, occlusion therapy at this age can lead at least to a limited improvement of visual acuity.

Key words anisomyopie - myelinated nerve fibers - amblyopia - strabismus - syndrome

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S. 37-39 (Art. 448)

Modified moisture chamber
Martin Winter, Christian Kandzia

Background Moisture chambers can protect the eye in corneal lubrication or eyelid closure disorders. However, in cases with protrusio bulbi or pronounced chemosis conjunctivae direct damaging contact of the cornea or conjunctiva on the one hand and the inside of the moisture-chamber-bandage on the other hand are possible. Since commercial moisture-chamber-bandages are not available with different internal radii, new methods are necessary to increase the distance between the bandage and the eye.

Material and methods A special pressure relieving foam dressing used in the therapy and prophylaxis of decubitus was prepared in such a way that a periocular attachment was enabled and an opening for the eye was left blank. This central opening was covered with a commercial moisture-chamber-bandage. Five test persons and two ventilated patients with protrusio bulbi and manifest lagophthalmus were treated with the modified moisture chamber. The relative humidity within the bandage was measured.

Results The modified moisture chamber allows an individual adaptation to the periocular shape of the face and rises the level of the monoculus for about 7 mm. The internal relative humidity was for eight hours at 98% in both test persons and patients. All test persons felt more comfortable with the modified moisture chamber on their skin.

Conclusions The presented modified moisture chamber is a derivative of the commercial monoculus bandage for patients with sensitive protrusio bulbi.

Key words Lubrication disorders - eyelid closure disorders - protrusio bulbi - periocular skin lesion - moisture chamber

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S. 40-43 (Art. 459)

A new measuring method of non-contact-tonometry
Kai-Uwe Plagwitz, Klaus Lemke

Background The measuring value of intraocular pressure (IOP) in non-contact-tonometry (NCT) depends on IOP and is additionally highly influenced by the biomechanical parameters of the cornea. These parameters (especially corneal thickness) differ among several patiens. It is desirable to characterize this influence and to correct the measuring value during the IOP measurement. The new tonometer consists of an air pulse applicator generating an air pulse with a ramp-shaped rising and a sharp decay after switching off and a Michelson-type laserinterferometer for detecting the corneal movement during the air pulse application and the oscillation after switching off the air pulse.

Method The method was tested with a mechanical phantom eye. The pressure inside the chamber of the phantom is adjustable. Measuring surfaces, which have to simulate the shape and the elastic properties of the cornea, are made of soft silicon rubber and fabricated with different thicknesses.

Results Measurement results show that both the rise of the corneal deformation and the damped oscillation (frequency and damping) depend from material thickness and internal pressure of the phantom eye.

Conclusion Thus a characterization of the influence of the mechanical properties and a determination of a corrected IOP-value are possible. The task at present is the investigation and formulation of the mathematical dependences.

Key words intraocular pressure - non-contact-tonometry - biomechanical parameters - laserinterferometer - corneal deformation - oscillation measurement - phantom eye

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S. 44-49 (Art. 452)

Ocular bacteriosis in a patient with aplastic anemia
Christoph W Spraul, Heinrich JG Roth, Peter Möller, Gabriele E Lang, Gerhard K Lang

Background For more than a century it has been recognized that bacteria may infect the eye by way of the blood stream. Until fifty years ago, eyes so afflicted nearly always were blinded and a majority of the victims died from overwhelming sepsis. Although effective antibiotics are available today the prognosis is still guarded.

Case report A 39-year-old physician died 6 years after he was diagnosed for idiopathic aplastic anemia. He had developed pseudomonas aeruginosa bacteremia and later a therapy refractive pneumonia caused by aspergillus which had led to respiratory failure. The patient had experienced a marked loss of visual acuity in his left eye ten days before he died. Ophthalmic examination at that point displayed signs of endophthalmitis, hyphaema, and heterochromic irises. The eyes were obtained postmortem and histologic examination of the left eye displayed numerous bacilli forming cuffs around blood vessels and a sheet between the necrotic retinal pigment epithelium and Bruch's membrane. No inflammatory response to the bacilli was present. The bacilli could be demonstrated with a Giemsa stain and could also be identified with electron microscopic examination.

Discussion The histologic results in our patient displayed numerous bacilli without inflammatory reaction which was a result of the aplastic state. Therefore, this disease was classified as "ocular bacteriosis". The blood-ocular barrier undergoes direct assault with intraocular inflammation and the impermeability to blood-borne antibiotics is lost. However, with the lack of an inflammatory reaction the permeability to antibiotics may be too low and the achieved concentration insufficient.

Key words Aplastic anemia - bacteriosis - endophthalmitis - pseudomonas - sepsis

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S. 50-52 (Art. 458)

Eye movement abnormalities as a sign for the diagnosis in Niemann-Pick disease type C
Dora Lengyel, Markus Weissert, Luzius Schmid, Irene Gottlob

Background Eye movement abnormalities in familial mental retardation syndrome should lead to the suspicion of a storage disorder, including Niemann Pick disease type C, Gaucher's disease, abetalipoproteinemia and Wilson's disease. The eye movement abnormalities in our two patients were suggestive of Niemann Pick disease type C, characterized by initial loss of voluntary vertical eye movements and subsequent loss of horizontal eye movements, with preservation of the vestibulo-ocular response. The characteristics of eye movements in storage disorders are different. In Gaucher's disease a progressive horizontal gaze palsy, in abetalipoproteinemia a particular type of internuclear ophthalmoplegia with nystagmus of the adducting eye and in Wilson's disease slowing of saccades may be observed.

Patients We evaluated two mentally retarded sisters with unclear diagnosis at the age of 34 and 27 years. At the age of 24 and 21 a vertical gaze palsy led to the diagnosis of Parinaud syndrome.

Results At the time of our examination both sisters were unable to perform voluntary horizontal or vertical saccades or pursuit eye movements. The vestibulo-ocular reflex was present in all directions. Optokinetic nystagmus and convergence were absent. This clinical picture led us to a suspicion of Niemann-Pick disease type C, confirmed by the presence of sea-blue histiocytes in the bone marrow biopsy.

Conclusion These cases demonstrate that the pattern of eye movement disorders in some syndromes associated with mental retardation can give important clues in the determination of the diagnosis.

Key words Niemann-Pick disease type C - vertical gaze palsy - vestibulo-ocular response - convergence deficit - sea-blue histiocyts

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S. 53-54 (Art. 456 DF)

Eccrine spiradenoma of the eyelid
Josef Amann, Christoph W Spraul, Thorsten Mattfeld, Gerhard K Lang

Patient A 60-year-old woman was evaluated for a nodular tumor in her right upper eyelid, which has developed over the last four years. The tumor measured 10x8 mm and was ulcerated. The patient's ophthalmologic und medical history was normal. Clinically, a basal cell carcinoma was suspected, and an excision was carried out under local anaesthesia. The histopathology was suggestive for an eccrine spiradenoma.

Conclusion Eccrine spiradenomas rarely involve the eyelids. This tumor represents a benign, usually painfull, sweat gland tumor. The possibility of sweat gland tumor should be kept in mind in the diagnosis of eyelid tumors. The complete excision is the only therapeutic option.

Key words Eyelid - eccrine - spiradenoma

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