AUGENHEILKUNDE 214/1999 – ISSUE 2

Abstracts:

S. 061–070 (Art. 457)

Vitreoretinal surgery in the treatment of neovascular glaucoma
Aristidis Psichias, Karl Ulrich Bartz-Schmidt, Gabriele Thumann, Gunther K Krieglstein, Klaus Heimann

Purpose Neovascular glaucoma develops on a background of ischemic ocular pathologies, such as diabetic eye diseases or central retinal vein occlusion. Development of neovascular membranes in the chamber angle leads to elevated intraocular pressure. Since treatment by cyclodestructive therapy or drainage surgery often fails, we have examined intense antiproliferative surgery as a treatment for advanced neovascular glaucoma.
Patients and Methods Thirty-two patients with neovascular glaucoma subsequent to central vein occlusion or advanced diabetic retinopathy underwent antiproliferative surgery, which comprised vitrectomy, panretinal laser treatment and direct laser coagulation of the ciliary processes, followed by silicone oil tamponade. Patients were followed for a minimum of 1 year and as long as 3 years.
Results After one week following surgery the intraocular pressure (IOP) was normal, ranging from 8 to 21 mm Hg, in 52% (15/29 eyes), after 3 months the IOP was normal in 50% (16/32 eyes), after 6 months the IOP was normal in 59% (16/27 eyes) and after 1 year the IOP was normal in 72% (18/25 eyes). Of the 10 eyes that lost all sight after the surgery, 7 eyes had a history of central vein occlusion. Hypotony was observed in 6% (2/32) of the eyes 3 months following surgery; after 6 months hypotony was present in 15% (4/27) of the eyes and after 1 year hypotony was present in 12% (3/25) of the eyes.
Conclusions The theoretical premise of our surgical intervention (antiproliferative surgery) is based on the assumption that laser treatment interrupts the self enhancing pathway of retinal ischemia, release of proliferative factors and increase in intraocular pressure. The silicone oil endotamponade prevents postoperative complications and supports the rapid regression of rubeosis iridis by separating the anterior from the posterior segment.
Key words Neovascular glaucoma – vitrectomy – panretinal photocoagulation – cyclophotocoagulation – silicone oil tamponade

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S. 071–076 (Art. 467)

O44 – a solvent for silicone oil adhesions on intraocular lenses
Hans Hoerauf, Dirk-Henning Menz, Joachim Dresp, Horst Laqua

Aim To examine the efficiency of O44, a partial fluorinated octane, as a solvent for silicone oil adhesions on intraocular lenses.
Materials and Methods After placing silicone- and PMMA-lenses in silicone oil, the adhesions were treated with O44. The extent of silicone oil adhesions and the effectiveness of O44 were studied by gross microscopy by scanning electrone microscopy (SEM) and combined energy dispersive spectrometry (EDX). Furthermore an explanted silicone lens with oil adhesions was treated with O44 and examined. To simulate the effect of adhesion proteins PMMA- and silicone lenses were placed in silicone oil and human plasma. Results With EDX it was possible to prove that O44 is able to remove silicone oil adhesions from PMMA-lenses. The removal from an explanted silicone lens by O44 could be demonstrated by light microscopy. Silicone oil adhesions on intraocular lenses (IOL’s) in vitro showed a different oil coverage than the IOL in vivo. Silicone lenses in vitro were often covered by a homogenous oil film and therefore the demonstration of the silicone adhesions and of the efficacy of O44 was difficult. The adhesions of IOL’s placed additional in human plasma did not show any differences.
Conclusions O44 may be a successful intraoperative tool to remove silicone oil adhesions avoiding explantation of silicone oil contaminated IOL’s. Silicone oil adhesions in vivo seem to be influenced by adhesive proteins.
Key words Partial fluorinated alcane – intraocular lenses – silicone oil – silicone oil adhesions

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S. 077–083 (Art. 468)

Immunohistochemical characterisation of surgically excised choroidal neovascularisations in age-related macular degeneration
Ralph Wiezorrek, Alexander Arthur Bialasiewicz, Hansjörg Schäfer, Gisbert Richard

Aim The objective of the study was to gather further information about the pathogenesis of choroidal neovascularisations (CNV), which is still not clearly understood, and to establish criteria for making decisions on a appropriate therapy. Immunohistochemical characterisation should allow a more comprehensive evaluation of cellular components of the membranes and their functional role.
Patients and methods In 29 patients (16 women, 13 men) with age-related macular degeneration ranging in age from 46 to 91years (mean age, 76.4 years), CNV were excised by pars-plana vitrectomy. Sections were stained with hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) and examined by light microscopy. For the immunohistochemical characterisation of the surgical specimens the following antigenetic determinants were used: glial fibrillary acid protein (GFAP) for glial cells, synaptophysin for neuronal cells, neuron-specific enolase (NSE) for neuronal and neuroectodermal cells, CD 31 for endothelial cells and pancytokeratin (KL1) for cells of the retinal pigment epithelium (RPE). Cells undergoing apoptosis were labeled with the TUNEL technique
Results 22 (76%) surgical specimens showed TUNEL positive cells in the connective tissue, vascular endothelium and retinal pigment epithelium. Positive immunostaining of neuronal antigenetic determinants was found for glial fibrillary acid protein in 22 patients (76%), for synaptophysin in 28 patients (97%) and for neuron-specific enolase in 21 patients (72%) CNV. The epithelial marker KL1 was positive in 28 patients (97%) and the endothelial marker CD 31 in 20 patients (69%).
Conclusion The immunohistochemical analyses of CNV showed that in the majority of cases during the excision of choroidal neovascularizations in addition to scar tissue and connective tissue also parts of the native retinal pigment epithelium and of the neurosensory retina are removed which is only partly visible with standard staining techniques. These findings suggest that the mostly not satisfying postoperative results are partly due to the damage of neuronal cells and a partial loss of the retinal pigment epithelium. Apoptosis as a regulating mechanism in choroidal neovascularization. The variable appearence of apoptosis suggests that it is possibly related to the degree of activity of CNV.
Key words macula degeneration – choroidal neovascularisation – pathology – immunohistochemistry – apoptosis

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S. 084–089 (Art. 481)

Enzymatically induced posterior vitreous detachment in proliferative diabetic vitreoretinopathy
Lutz Hesse, Peter Kroll

Background Complete detachment of the posterior vitreous cortex is an important aim in the treatment of proliferative diabetic vitreoretinopathy (PDVR). Today a posterior vitreous detachment (PVD) can only be achieved during vitrectomy. A randomized pilot study was started to evaluate wether intravitreally injected TPA is sufficient to induce a PVD in diabetic eyes.
Patients and methods Eight weeks prior to vitrectomy because of proliferative diabetic vitreoretinopathy (non-clearing haemorrhage, fibrovascular proliferations) 20 eyes which had an attached vitreous received a cryopexy of the peripheral retina. In 11 eyes that had been selected at random 10 µg of recombinant tissue plasminogen activator were injected midvitreally 24 hrs later. A newly formed PVD was assessed by means of biomicroscopy or ultrasound.
Results A newly formed partial (np3) or complete (np7) PVD was found in 10 of 11 TPA-treated eyes versus one partial detached vitreous in the control group. In 3 younger patients PVD developed exclusively after TPA-injection. We did not observe severe changes of the ERG, decrease of visual acuity, severe new vitreous haemorrhages or opacities of the lens. In 3 eyes (2 eyes of the controll group) a circumscribed retinal detachment developed during the follow-up period.
Conclusions The described technique can be used in diabetics without severe side effects. It facilitates the removal of the vitreous cortex and may be a valuable adjunct to the surgical management of PDVR. Unlike other proteases TPA is available for clinical use through recombinant DNA technology which allows standardized enzymatic activities, steril and non-infectious conditions.
Key words tissue plasminogen activator – posterior vitreous detachment – proliferative diabetic vitreoretinopathy – intravitreal injection

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S. 090–095 (Art. 475)

Transpupillary thermotherapy of choroidal melanoma
Hanka Schneider, Konstanze Fischer, Rainer Fietkau, Rudolf F Guthoff

Purpose The purpose of this report is to evaluate the efficacy of transpupillary thermotherapy (TTT) to treat choroidal melanoma.
Patients and method 17 patients with choroidal melanoma were treated. 6 patients with small tumors close to posterior pole received TTT only. 11 patients were treated simultaneously with TTT and Ru 106 brachytherapy. To perform TTT a diode laser with a beam diameter of 1.5 to 3 millimeters was used. Exposure time ranged from 60 to 90 seconds until a light grey appearence of the retinal surface was reached. Follow-up examinations were performed at 1-month intervals. If the tumor was partially regressed additional TTT was performed to reach the endpoint of a chorioretinal scar.
Results All tumors exhibited a reduction of tumor height in a mean follow-up period of 14.25 months. Side effects were minimal.
Conclusions Treatment with TTT may be useful as a complementary modality to brachytherapy. A longer follow-up time is necessary for final evaluation.
Key words transpupillary thermotherapy – brachytherapy – choroidal melanoma

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S. 096–099 (Art. 476)

Radiation therapy of occult choroidal neovascularisation (CNV) in age-related macular degeneration (AMD)
Andreas WA Weinberger, Sebastian Wolf, Thomas Kube, Uta Solbach, Hildegard Dobberstein, Ursula M Schleicher, Bernd Kirchhof

Background Occult choroidal neovascularisation secondary to age-related macular degeneration cause severe visual loss due to exsudation, hemorrhage and fibrovascular scarring. So far, no efficient treatment of this condition could be established. Recently, some publications described an improved prognosis after low-dose radiation therapy of the neovascular membranes.
Patients and methods Patients with occult choroidal neovascularisation as defined by the Macular Photocoagulation Study were inclosed in our study. Irradiation with Photons (10 to 12 MeV) in fractions of 5!2 Gy were administered. At three-month follow-up intervals visual acuity a complete ophthalmological examination including visual acuity, fluorescein- and ICG-angiography as well as fundus photography was performed.
Results In our study 64 patients (74B7 years) with occult CNV secondary to AMD were included. Follow-up was between 3 and 39 months (14.5B10). Compared to studies who investigated the natural history of this disease, the visual acuity measured in our study did not differ significantly from the natural course.
Conclusions Our results do not support the general use of radiation therapy in patients with occult choroidal neovascularisation secondary to AMD. However, the controlled multicenter studies might provide a better basis for a general recommendations.
Key words Age-related macular degeneration – occult choroidal neovascularisation – radiation therapy – pilot study

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S. 100–102 (Art. 484)

Intravitreal Gas Injection Diminishes Hyaluronic Acid
Harvey Lincoff, Ingrid Kreissig, Jason Horowitz, Ronald Silverman

Summary

Objectives To determine if compression of the vitreous by an intraocular gas bubble diminishes the concentration of hyaluronic acid (NaHA).
Materials and Methods Eighteen albino rabbits had air, xenon or perfluoroethane (C2F6) injected into the vitreous to displace 12.5% to 90% of the vitreous volume. After the gas was absorbed, the vitreous was analyzed for NaHA by the Carbazole method (1, 13).
Results A 90% displacement diminished the NaHA concentration by 18.6%. Lesser displacements caused a lesser loss, but the differences are not significant.
Conclusion Intraocular gas injections, both large and small, reduce the concentration of NaHA and destabilize the vitreous structure.
Key words Intraocular gas – perfluoroethane (C2F6) – vitreous – hyaluronic acid

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S. 103–106 (Art. 477)

Subretinal transplantation of confluent pigment epithelium: A novel device for non-traumatic tissue handling
Ulrich H Steinhorst, Udo Wichmann, Timo Kastern, Uwe Schaardt

Background Subretinal transplantation of pigment epithelium may be a therapeutic option in the treatment of age-related macular degeneration. Suspensions of pigment epithelial cells as well as confluent cell layers are being considered.
Methods We developed a surgical device which permits to load living tissue, without exerting mechanical stress to the cells themselves, and to deliver it precisely onto the subretinal target site.
Results After having been grown to confluency on extracellular matrix, the tissue can be fixed on a cannulated spoon by creating a vacuum on its undersurface. The spoon is connected to a silicone tube attached to a syringe. The syringe is used to produce a vacuum which is delivered to the tissue through the perforated surface of the spoon. After directing the spoon into the subretinal space, the tissue can be discharged by releasing the vacuum.
Conclusions In previous studies large cannulas have been used for injecting coherent cell layers underneath the retina. This technique frequently resulted in major distortion of the tissue. Furthermore, correct apico-basal orientation of the tissue often could not be achieved. We present a novel concept of a device which exerts vacuum to the entire underside of the graft allowing to hold it in position without distorting it. By releasing the vacuum, the graft can be positioned in the site of RPE atrophy. (Patent Reg.No. 29819018.4, München, Germany, 1998)
Key words Macular degeneration – pigment epithelium – RPE – transplantation – surgical devices – vitreoretinal surgery

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S. 107–111 (Art. 486)

Intravitreal endoscopic visualization of intraocular ganciclovir devices: Improved long-term treatment of CMV retinitis
Frank Heinz Johannes Koch, Hermann Oskar Cornelius Gümbel, Lars-Olof Hattenbach, Christian Ohrloff

Background The recent development of 20- and 19-gauge diameter endoscopes allows an excellent direct intravitreal visualization of intraocular morphology. A gradient index (GRIN) endoscope (Insight Instruments, Lake Mary, FL, USA), which combines a small diameter (0.89 mm, 20 gauge) and an exceptional optical resolution, can be used as a diagnostic tool for the assessment of the safety and vitreous interaction of sustained release intraocular devices which have been designed to deliver ganciclovir (Vitrasert®) over a period of 8–12 months and were successively implanted in several eyes.
Patients and Methods 78 eyes of 49 patients received 100 ganciclovir implants between November 1995 and July 1998. In six patients who received additional implants, the GRIN endoscope was used as an optical control of wound healing processes and Vitrasert® positioning after implantation of prior devices (two-point suturing technique).
Results In all of these six eyes, a clinical stabilization of the cytomegalovirus retinitis was noted. Endoscopic observation of the scleral 5-mm incision revealed no gaps after two-point suturing of the device. Only one of six eyes showed significant vitreous tractions around the Vitrasert®. However, the struts of all pellets were completely covered by a fibrous membrane. Occasional fibrous plaques were noted on the surface of devices which presumably had been damaged by surgical manipulations. In one case, the endoscopic examination disclosed the suprachoroidal implantation of a device. In this eye, no signs of retinal toxicity or recurrence of CMV retinitis were observed.
Conclusions High resolution endoscopy of the vitreous cavity appears to be an effective method for the control of intraocular drug delivery devices. Basically, the repeated implantation of intraocular ganciclovir implants can be considered a safe method in the management of relapsing CMV retinitis. However, the endoscopic observation of fibrous membranes covering the struts suggest that the explantation of an intraocular device has the potential for various intraoperative complications (e.g. hemorrhages, traction, tears, retinal detachment). Therefore, we would recommend the additional implantation of further implants rather than a replacement.
Key words intraocular device – pars plana vitrectomy – high resolution endoscopy – gradient index endoscope – wound healing

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S. 112–115 (Art. 483)

Maculopathy caused by Nd:YAG-laser-accident
Christian Blümel, Jan Brosig

Background Since the construction of the first laser in the sixties and the extended use in medicine, technology and hobby the number of accidents has increased. Appreciated to therapy concepts are missing at the time.
Patient A 19 year-old-man was hit by the impulse of an military hand-held rangefinder (Nd:YAG with a wavelength of 1064 nm) on the right eye. The visual acuity dropped to 1/35 and a central scotoma with metamorphopsia occurred immediatly after the accident. The ophthalmological findings showed a distinct submacular hemorrhage. The therapy with Prednisolon intravenous and daily parabulbar, vitamin C, indomethacin systemical and lokal application resulted in an increase of visual acuity up to 0,4 and a reduction of central scotoma from 8° to 2°.
Conclusion Systemical and local use of antiphlogistic and antiinflamatoric substances may partially reduce the vision limitating scar formation. Application of antioxidants to neutralize the toxic radicals that arise by tissue decay should be given additionally to the cyclopegic medication. Special attention should be payed to the prevention of such laser accidents.
Key words maculopathy – Nd:YAG laser – laser accident

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S. 116–119 (Art. 446)

An attempt to extract an intraretinal nematode located in the papillomacular bundle
Wolfgang Meyer-Riemann, Jörgen Petersen, Martin Vogel

Background The nematode infection of the retina is a rare disease with sight threatening prognosis. Untreated eyes usually become blind. There are different types of clinical progression: granuloma causing tractional detachment, chronic inflammation called diffuse unilateral subacute neuroretinitis (DUSN) and rapid loss of vision named "ocular wipe-out syndrome". Efficient drugs are not available. The progression of the disease can be stopped by killing the nematode by means of photocoagulation. For parasites in the periphery of the fundus this is the therapy of choice. Photocoagulation of the nematode close to the posterior pole can cause severe damage to the visual functions. There is a need for a less detrimental treatment.
Patient and methods We report on a 48-year-old woman with an intraretinal nematode inside the papillomacular bundle. At an early stage of the disease with normal visual acuity the eye was vitrectomized and a posterior vitreous detachment performed. It was intended to extract the worm out of the retina in toto. The retina over the parasite was incised parallel to the nerve fibers, a tiny hook inserted and the worm pulled out. Results Only one half of the parasite could be removed since the adhesion of the parasite to the retina was stronger than its own cohesion. Nevertheless the inflammation rapidly regressed. Finally a small area of pigment mottling persisted around the former location of the parasite corresponding to a relative scotoma in the visual field. Visual acuity remained unchanged at full vision.
Conclusion We demonstrated that nematode larvae can be removed successfully from the central retina using vitrectomy techniques. By that means the damage to the visual functions can be limited. Near the posterior pole surgical extraction of the worm may be favorable compared to photocoagulation.
Key words Nematode infection – toxocara – parasite – vitrectomy – extraction

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S. 120–122 (Art. 460)

Retrolaminar infiltration of optic nerve after silicone oil instillation after vitrectomy
Hartmut Wenkel, Gottfried OH Naumann

Background Eyes after intravitreal silicone oil injection may suffer various complications. We report on a patient with deep retrolaminar changes in the optic nerve after silicone oil instillation with secondary angle-closure glaucoma.
Patient A 69-year-old female patient with aphakic retinal detachment of the right eye was treated by pars plana vitrectomy with silicone oil injection. After 41 months the patient presented with absolute secondary angle-closure glaucoma with rubeosis iridis. The intraocular pressure was elevated up to 55 mm Hg. There was a peripheral retinal detachment and a pale deeply cupped optic disc. Due to increasing pain the blind eye was enucleated. Histology showed a mainly detached retina and silicone oil occupying the vitreous cavity. The optic nerve was deeply cupped and the parenchyma presented multiple cavernous spaces of various sizes. These presumptive silicone oil bubbles reached beyond the line of surgical transection, nine millimeters behind the globe.
Conclusion In comparison to Schnabel’s cavernous optic atrophy the vacuoles in the optic nerve in this patient were filled with silicone oil instead of acid mucopolysaccharides. A posterior migration of silicone oil into the orbital optic nerve can not be excluded, after long-term silicone oil tamponade and elevated intraocular pressure.
Key words Cavernous optic atrophy – opticoneuropathy – silicone oil – vitreous surgery

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