[Basic principles and clinical application of retinal laser therapy]. / Grundlagen und klinische Anwendung der Lasertherapie an der Netzhaut.

The scientific background of laser photocoagulation of the ocular fundus was studied extensively by several investigators in the 1970 s and 1980 s. The basic principles were successfully resolved during that time and clinical consequences for proper application of the laser photocoagulation for various diseases were deduced. The present paper gives an overview about the physical basics of laser-tissue interactions during and after retinal laser treatment and the particular laser strategies in the treatment of different retinal diseases. Thus, it addresses the issue of the impact on tissue of laser parameters as wavelength, spot size, pulse duration and laser power. Additionally, the different biological tissue reactions after laser treatment are presented, such as, e. g., for retinopexia or macular treatments as well as for diabetic retinopathies. Specific laser strategies such as the selective laser treatment of the RPE (SRT) or the transpupillary thermotherapy (TTT) are presented and discussed.

[Diagnostics of metamorphopsia in retinal diseases of different origins]. / Diagnostik von Metamorphopsien bei Netzhauterkrankungen unterschiedlicher Genese.

We investigated the ability of preferential hyperacuity perimeter (PHP) and Amsler grid testing to detect metamorphosia in patients with macular hole (MH), central serous retinopathy (CSR), epiretinal membranes (EM), intermediate AMD (iAMD), classic and occult choroidal neovascularization (CNV) due to AMD, and compared the results. A total of 147 patients (n =153 eyes) with classic (35 eyes) and occult (38 eyes) CNV, iAMD (13 eyes), MF (23 eyes), RCS (11 eyes), EM (13 eyes) and control group (20 eyes) were involved. All of these patients underwent corrected visual acuity and eye examinations inclusive of the Amsler grid. The PHP test was performed after pupil dilation. In all patients, fundus photography and optical coherence tomography (OCT) (Humphrey/Zeiss OCT III) were performed. In patients with CNV and CSR a fluorescein angiography was also performed. Metamorphopsia detection rates by Amsler grid and PHP were compared statistically. The sensitivity of PHP vs Amsler grid in detecting metamorphosia was 69% vs 85% in patients with MH, for CSR 64% vs 73%, EM 77% vs 100%, iAMD 85% vs 100%, classic CNV 83% vs 94% and occult CNV 81% vs 71%. The results for patients with occult CNV were significant (P =0.046), using the chi(2)-test. The PHP-test showed high sensitivity for diagnosing CNV. In occult CNV, PHP was superior to the Amsler grid in detecting metamorphopsia. In the other diseases involving the macular (MH, EM, CSR, iAMD), the detection rate and sensitivity of the Amsler grid was superior to PHP.

[The Position of the Retinological Society, the German Ophthalmological Society and the Professional Association of Ophthalmologists--comments on the current therapy for neovascular AMD]. / Konsenspapier der Retinologischen Gesellschaft, der Deutschen Ophthalmologischen Gesellschaft und des Berufsverbandes der Augenärzte - Stellungnahme zur aktuellen Therapie der neovaskulären AMD.

BACKGROUND: Until recently, only two options were available for the treatment of choroidal neovascularization (CNV) due to age-related macular degeneration (AMD): laser photocoagulation and photodynamic therapy (PDT) with verteporfin. However, potential new treatments for CNV are under development, and data from phase III clinical trials are now available. Referring to these data, expert guidance is required to supply ophthalmologists with expertise in the management of AMD to select and use the most appropriate therapies in the treatment of neovascular AMD. METHODS: The therapeutic modalities discussed include thermal laser photocoagulation, PDT with verteporfin, triamcinolone acetonide and the possible combination with PDT, anecortave acetate, pegaptanib sodium and ranibizumab. After a short description of the treatment principles, a summary of the discussion of all relevant study results of the different treatment options with respect to the different subtypes of neovascular AMD is presented. These discussions resulted in an "up-to-date" recommendation of therapeutical strategies in neovascular AMD. RESULTS: For subfoveal lesions with predominantly classic CNV, or with occult with non-classic CNV and a lesion size < or = 4 macular photocoagulation study (MPS) disc areas (DA), PDT with verteporfin is recommended; for subfoveal lesions with minimally classic CNV, treatment with PDT or pegaptanib sodium is possible, even if there are some problems with the statistics in the studies with both treatment modalities. PDT with verteporfin should be considered for juxtafoveal lesions that are so close to the fovea that laser photocoagulation would almost certainly extend under the center of the foveal avascular zone, and for all other juxtafoveal lesions and for extrafoveal lesions laser photocoagulation is suggested. Therapy should be performed not later than one week after the initial fluorescein angiogram upon which the clinical decision for treatment is based. At each follow-up best-corrected visual acuity and a fundus examination should be performed as well as a fluorescein angiography every three months. CONCLUSIONS: These recommendations provide good clinical guidance for the choice and use of laser and pharmacotherapies for the management of CNV due to AMD. Revisions of the recommendations will be required as new data become available.

Macular function and morphology after peeling of idiopathic epiretinal membrane with and without the assistance of indocyanine green.

AIM: To investigate macular function and morphology after surgical removal of idiopathic epiretinal membrane (IEM) with and without assistance of indocyanine green (ICG). METHODS: A retrospective study as a consecutive case series, of 39 patients with IEM. 39 patients, 23 female, 16 male, mean age 67 years, underwent standard three port pars plana vitrectomy with removal of epiretinal membrane. Two groups of patients were consecutively operated: in 20 patients ICG 0.1% in glucose 5% was used to stain the epiretinal membrane. 19 patients underwent the identical procedure but without use of ICG. Postoperative follow up was 1-92 months (mean 15.5 months). Functional outcome was assessed with subjective improvement, best corrected visual acuity (BCVA), Amsler grid test, 10 degrees and 30 degrees automated perimetry (Heidelberg visual field analyser) (HFA), and Goldmann kinetic perimetry. Macular morphology was assessed with stereoscopic biomicroscopy and optical coherence tomography (OCT). The main outcome measures were macular function as determined by BCVA, presence of visual field defects, and metamorphopsia as determined by Amsler grid test, macular morphology as determined by slit lamp biomicroscopy, and OCT. RESULTS: BCVA improved in 28 patients, remained unchanged in eight patients, and decreased in three patients. Improvement of BCVA was statistically significant in both groups (p = 0.003). Mean BCVA in patients operated with ICG improved from 0.33 preoperatively to 0.53 postoperatively. Mean BCVA in patients operated without ICG improved from 0.32 preoperatively to 0.54 postoperatively. Reduction of macular oedema as measured by OCT was statistically significant in both groups (p<0.01). There was no statistically significant difference in postoperative BCVA, macular oedema as measured by OCT, postoperative Amsler grid test, and subjective improvement between the two groups. The incidence of residual or recurrent epiretinal membrane was greater in the group operated without ICG (p = 0.014). Visual field defects were detected in one patient operated with ICG and in three patients operated without ICG. CONCLUSIONS: Removal of epiretinal tissue with or without assistance of ICG improved visual function and reduced macular oedema in most patients. Adverse effects clearly attributable to the use of ICG were not observed but further investigation is warranted.

New substances for intraocular tamponades: perfluorocarbon liquids, hydrofluorocarbon liquids and hydrofluorocarbon-oligomers in vitreoretinal surgery.

UNLABELLED: Perfluorocarbon liquids (PFCLs) and heavy fluorocarbon liquids (HFCLs) are being increasingly used as soft tools during vitreoretinal surgery. However, since long-term intraocular tolerance is still unsatisfactory, at present complete removal at the end of surgery is recommended. With the aim to improve long-term intraocular compatibility and to enlarge the spectrum of clinical applications, modified HFCLs have been developed. HFCL-oligomers with a higher viscosity represent the latest perspective. All three groups of fluorocarbon liquids will be compared with respect to their physical and chemical properties, experimental and clinical results, and prospects for clinical applications. Common features of PFCLs, HFCLs and HFCL-oligomers are biological inertness, specific gravity higher than water, immiscibility with water or blood, and a high gas binding capacity. In PFCLs such as decalin, octane, or phenanthrene. All carbon atoms of the carbon backbone are completely fluorinated. In experimental and clinical use, emulsification, vascular changes and structural alterations of the retina have been described. By only partial replacement of hydrogen atoms by fluorine, the specific gravity of HFCLs is reduced, whereas lipophilic properties increase. Thus HFCLs are potential solvents for intraocular silicone oil remnants. However. after long-term application, side-effects are similar to those observed with PFCLs. Substances of this group, such as F6H6, F6H8, 044, and 062 are used intraoperatively and are currently being investigated for clinical long-term application. With the aim to avoid emulsification and to improve intraocular tolerance, we have developed HFCL-oligomers consisting of 2-4 HFCL molecules with increased viscosity. The oligomers were tolerated well in rabbit eyes for up to 4 months. In contrast to PFCLs or monomers, they did not emulsify nor show vascular alterations. ERGs returned to normal after removal of the oligomer from the eye. Histology of the retina showed mild alterations. CONCLUSION: according to physical properties, experimental intraocular compatibility and stability against emulsification, HFCL-oligomers are promising candidates for improved long-term tamponade of the lower retina. At present, indications for an application in human eyes have to be determined in clinical trials.

[Central retinal artery occlusion. Importance of selective intra-arterial fibrinolysis]. / Zentralarterienverschluss. Stellenwert der selektiven intraarteriellen Fibrinolyse.

BACKGROUND: Conventional treatment of a central retinal artery occlusion usually has a poor prognosis but intra-arterial fibrinolysis (IF) of the ophthalmic artery is an invasive treatment option. The importance of IF was evaluated in 62 patients with central retinal artery occlusion and in addition the risk spectrum for this disease was considered. MATERIAL AND METHODS: Data from charts of 62 patients were retrospectively analysed. Visual recovery after IF (n = 17) was compared to conventional treatment (e.g. decrease of IOP, improvement of rheological conditions, n = 45). Patients were excluded from IF if the occlusion was present for more than 8 h, if there was a history of bleeding and previous operations, or if they were older than 85 years. IF was performed using either urokinase (n = 7) or tPA (n = 10). RESULTS: Out of 62 patients, 22 (35%) with central retinal artery occlusion underwent catheterisation. Stenosis of the carotid artery excluded IF in 5 out of these 22 cases, therefore only 17 patients were treated by IF. Of the patients, 40 (65%) were excluded from IF for various reasons: 47% (19/40) arrived later than 8 h after occlusion, 17% (7/40) did not consent to IF, 15% (6/40) had medical contraindications and 13% (5/40) were over 85 years of age. Two patients required no IF because of a cilioretinal anastomosis with moderate visual acuity and another patient showed spontaneous visual recovery during ophthalmic examination. Of the 17 patients treated with IF, 4 achieved an improvement of visual acuity by more than 2 lines, no change of visual acuity was observed in 12/17 patients and 1/17 lost more than 2 lines after treatment. Of the 45 conservatively treated patients, 16 achieved improvement by more than 2 lines and no change occurred in 29/45 patients. Three patients treated with IF suffered from a stroke during treatment. The main risk factor for central retinal artery occlusion was high blood pressure in 32% of all cases and nicotine abuse in 16%. CONCLUSIONS: Many patients presented too late for IF. However, there was no statistical difference between patients with IF and conventional treatment with regards to the improvement of visual acuity. Additionally there is an increased risk of a stroke from IF, therefore a prospective study is necessary to evaluate the importance of IF. Stabilisation of high blood pressure may be the best prophylaxis for preventing a central retinal artery occlusion.

Exudative retinal detachment in macular hole surgery using platelet concentrates--a case report.

INTRODUCTION: Retinal detachment after macular hole surgery is a rare complication, usually occurring because of small, peripheral holes. We present a patient with a high bullous exudative retinal detachment following pars plana vitrectomy. CASE REPORT: A healthy 69-year-old patient presented with a macular hole stage III of the left eye. Corrected visual acuity was 20/200. Pars plana vitrectomy was performed without peeling of the internal limiting membrane or an epiretinal membrane, a few drops of platelet concentrate were instilled onto the hole, and the bulbus was filled subtotally with a non-expanding SF6/air mixture. On the 3rd postoperative day a small retinal detachment of the inferior half of the retina was noticed that increased over the next 3 days until it reached the inferior vascular arcade. During the following 3 days a spontaneous remission occurred with complete reattachment of the retina. Six weeks after operation the retina was completely reattached, the macular hole was closed, and the visual acuity was 20/200 with a slight cataract. CONCLUSION: Retinal detachments after macular hole surgery are not always of rhegmatogenous nature but may also be exudative and related to an inflammatory reaction caused by adjuvants. When a retinal detachment occurs immediately after macular hole surgery without detectable holes it may be advisable to wait for some days before reoperation.

[Subretinal microphotodiode array as replacement for degenerated photoreceptors?]. / Subretinales Mikrophotodioden-Array als Ersatz für degenerierte Photorezeptoren?

A survey is given on the status of developments, concerning a subretinal electronic microphotodiode array that aims at replacing degenerated photoreceptors. Various prototypes have been developed, tested, and implanted in various experimental animals up to 18 months. The fact that electrical responses were recorded from the visual cortex of pigs after electrical stimulation by subretinal electrodes and the fact that responses are also recorded in-vitro in degenerated rat retinae, shows the feasibility of this approach. However, there are a number of open questions concerning the biocompatibility, the long-time stability, and the type of transmitted image to be solved before application in patients can be considered.

Studies on the feasibility of a subretinal visual prosthesis: data from Yucatan micropig and rabbit.

BACKGROUND: To estimate the feasibility of the subretinal concept of a visual prosthesis, animal models and prototypes, each representing a certain aspect of the final prosthesis, were utilised to test for requirements for such a medical device: (1) the ability to elicit--by electrical stimulation--event-related central activity in the central visual system, and (2) the long-term biocompatibility and biostability of the implant within the subretinal space. METHODS: (1) In rabbit and Yucatan minipig, cortical evoked potentials were recorded with chronically implanted epidural electrodes during stimulation with light flashes as well as during electrical stimulation in the subretinal space. Voltage pulses ranging from -3 V to +3 V were applied via an acutely implanted electrode array on a wired prototype. (2) For biocompatibility studies a silicon-based micro-photodiode array (MPDA) was used that closely resembled the design and composition of the final prosthesis. Fourteen months after implantation, angiography was performed and the histological findings of the retina in the immediate vicinity of the implant were evaluated. RESULTS: (1) In both rabbit and minipig, subretinal electrical stimulation resulted in evoked cortical potentials that were comparable to visual evoked potentials. The lowest threshold levels for the subretinal stimulation were 0.6 V for rabbits and 2 V for minipigs. (2) Long-term stability of an implanted MPDA and its biocompatibility were proven for a postoperative period of 14 months. CONCLUSIONS: Data from animal experiments with certain prototypes of the final prosthesis suggest the feasibility of the concept of a subretinal visual prosthesis: Both requirements were met: (1) the functioning of the subretinal stimulation and (2) the biocompatibility of the MPDA implant.

Epinephrine, but not dexamethasone, induces apoptosis in retinal pigment epithelium cells in vitro: possible implications on the pathogenesis of central serous chorioretinopathy.

BACKGROUND: The pathogenesis of central serous chorioretinopathy is poorly understood. It is believed to be due to dysfunction of the retinal pigment epithelium and/or choroid and has been associated with elevated levels of epinephrine and administration of corticosteroids. Epinephrine and corticosteroids have previously been shown to induce apoptosis (programmed cell death) in various types of cells. The objective of this study was to investigate whether these agents can induce apoptosis in cultured retinal pigment epithelium cells. This may help elucidate the pathogenesis of central serous chorioretinopathy. METHODS: Third-passage porcine retinal pigment epithelium cells were grown to confluence and incubated for 1-7 days in culture medium containing epinephrine (10(2)-10(9) pg/ml) or a corticosteroid, dexamethasone (4-4x10(4) ng/ml). The cultures were evaluated for apoptosis by phase-contrast microscopy and in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. RESULTS: Epinephrine (7x10(7)-10(9) pg/ml) induced apoptosis in a dose- and time-dependent manner. Exposure to lower concentrations of epinephrine (10(2)-6x10(7) pg/ml) and all tested levels of dexamethasone did not result in apoptosis. CONCLUSION: Retinal pigment epithelium cells may undergo apoptosis following exposure to elevated levels of epinephrine. These findings suggest a possible pathophysiologic mechanism for the development of central serous chorioretinopathy.

[Clinical results of intravitreal administration of tissue-type plasminogen activator (tPA) and gas for removal of subretinal hemorrhage in senile macular degeneration]. / Klinische Ergebnisse über die intravitreale Gabe von Gewebe-Plasminogen-Aktivator (tPA) und Gas zur Verdrängung von subretinalen Blutungen bei altersabhängiger Makuladegeneration.

BACKGROUND: Subretinal hemorrhage in age related macular degeneration (AMD) usually causes acute visual loss and is associated with poor visual prognosis. In order to prevent retinal damage and to perform laser treatment of the underlying choroidal neovascularization (CNV) the subretinal hemorrhage has to be removed from the macular region. This could be achieved by intravitreal injection of tissue plasminogen activator (tPA) and gas. PATIENTS AND METHODS: In 8 consecutive patients, suffering from a massive macular hemorrhage (duration of visual problems: mean 9 days), tissue plasminogen activator (tPA) (40 micrograms in 400 microliters BSS) and SF6-gas (0.75 ml) was transsclerally injected into the vitreous cavity to achieve liquification and displacement of the hemorrhage. RESULTS: In all patients liquification and displacement of the hemorrhage out of the macular region was achieved during follow up. During the first week after operation a significant increase of visual acuity was noticed in all patients, however ophthalmoscopically there was just little reduction of the hemorrhage in the foveolar area. After successful removal of the blood the choroidal neovascularization was treated successfully by laser coagulation in one patient. No laser treatment was performed in the other patients because of the subfoveal location of the neovascularisation or because of disciform scar. Visual acuity increased 4 lines after surgery. In one case the procedure was complicated by a persistent vitreous hemorrhage and vitrectomy had to be performed in another patient due to an endophthalmitis. CONCLUSION: Intravitreal injection of tPA assisted gas displacement of subretinal hemorrhage due to AMD leads to a significant increase of visual acuity during the first week after operation. Although a nearly complete removal of the hemorrhage out of the macular area could be achieved, it was difficult to differentiate this from the spontaneous course. Laser photocoagulation could be performed in only few cases.

Listeria monocytogenes-induced endogenous endophthalmitis in an otherwise healthy individual: rapid PCR-diagnosis as the basis for effective treatment.

PURPOSE: Listeria monocytogenes is a rare cause of endogenous endophthalmitis. To date 15 cases have been published in the literature. All eyes showed similar clinical features and profound visual loss mainly due to delayed diagnosis. METHODS: An additional case of an otherwise healthy 73 year-old male, who was referred to our hospital because of acute iridocyclitis with secondary glaucoma, is reported. Within a few days the severity of the intraocular infection increased dramatically, resulting in the clinical picture of acute endophthalmitis. RESULTS: In contrast to most published cases, early identification of the causative pathogen in the aqueous humor after anterior chamber puncture using polymerase chain reaction (PCR) and the initiation of a specific, systemic antibiotic medication, resulted in-complete recovery of visual acuity. CONCLUSIONS: PCR is very useful for the identification of the pathogen in intraocular infections.

Listeria monocytogenes-induced endogenous endophthalmitis in an otherwise healthy.

PURPOSE Listeria monocytogenes is a rare cause of endogenous endophthalmitis. To date 15 cases have been published in the literature. All eyes showed similar clinical features and profound visual loss mainly due to delayed diagnosis. METHODS: An additional case of an otherwise healthy 73 year-old male, who was referred to our hospital because of acute iridocyclitis with secondary glaucoma, is reported. Within a few days the severity of the intraocular infection increased dramatically, resulting in the clinical picture of acute endophthalmitis. RESULTS In contrast to most published cases, early identification of the causative pathogen in the aqueous humor after anterior chamber puncture using polymerase chain reaction (PCR) and the initiation of a specific, systemic antibiotic medication, resulted in complete recovery of visual acuity. CONCLUSIONS: PCR is very useful for the identification of the pathogen in intraocular infections. (Eur J Ophthalmol 1999; 9: 53-7).

Treatment of pigment epithelial detachments due to age-related macular degeneration with intra-ocular C3F8 injection.

PURPOSE: To flatten pigment epithelial detachments (PED) due to age-related macular degeneration in an attempt to visualize the underlying choroidal neovascularization by fluorescein angiography (FA) and reveal a treatment target. METHODS: Nine patients with PED received intravitreal gas injections via the pars plana and postured face down. Fluorescein angiograms were obtained before and after gas injection. In two patients, retinal scotopic sensitivity was also measured. RESULTS: Eight patients demonstrated change in the shape and size of the PED following gas injection. Four patients showed a better delineation of underlying structures on FA. Three patients had focal laser treatment to the newly visible choroidal neovascular complex, but this was successful in only one patient with flattening of the PED. CONCLUSION: Pigment epithelial detachments can be modified by intravitreal gas injection in some patients, but this treatment did not have a major impact on overall outcome or management.

Diagnosis of infectious endophthalmitis after cataract surgery by polymerase chain reaction.

PURPOSE: To ascertain whether the use of the polymerase chain reaction (PCR) technique leads to more rapid diagnosis of infectious endophthalmitis after cataract surgery. SETTING: University Eye Clinic Regensburg, Germany. METHODS: The aqueous humor and vitreous of 16 eyes with infectious endophthalmitis (10 acute, 6 delayed) were evaluated by microscopy, diagnostic culture, and PCR to detect the infectious agent. RESULTS: Microscopy of the vitreous was positive in 3 eyes and the culture media results were positive in 7 eyes, all with acute endophthalmitis. Significantly fewer positive results were obtained in the aqueous humor. Using PCR, an infectious agent was detected in the aqueous humor of all 16 eyes and in the vitreous of 14. The vitreous sample was negative in 2 eyes with delayed endophthalmitis. CONCLUSIONS: Detection of the infectious agent was more successful using PCR than using conventional microbiological tests, especially in the diagnosis of delayed endophthalmitis where the pathogen was detected in the aqueous humor in all eyes.

[Surgical worm extraction in loa loa ophthalmia]. / Chirurgische Wurmentfernung bei Loa-Loa-Ophthalmie.

BACKGROUND: Loa Loa is a chronic parasitemic disease which is endemic in the tropical rain forests of Western Africa. Vector of this disease is a mangrove fly with the name Chrysops. Besides the eye worm and skin affections a systemic infection with microfilariae is common. PATIENT: A West African tourist from Bangibe showed up at the university eye clinic. His complaints were a red eye and a mobile subconjunctival tumor (Fig. 1) that showed vermiform movements. The worm was transparent and 4-5 cm in length. After topical anaesthesia and the attempt to paralyze the worm (1) with Pilocarpine 2% it vanished. Two days later the patient showed up in the morning for the planned blood test. No worm was visible at that time but at noontime the blood test was carried out and at that time the worm was visible in the nasal conjunctiva. This time the worm was removed without delay under topical anaesthesia. The worm was fixed with a forceps through the conjunctiva which was opened for 0.5 cm. The worm was grasped with a second forceps and drawn out under massive vermiform movement. Systemic therapy was recommended with Hetrazan (Diethylcarbamazine) using Corticosteroides and Antihistamine to minimize allergic side effects by the therapy due to the systemic microfilariae blood load. Eosinophilia was 8%. CONCLUSIONS: A subconjuctival Loa Loa worm can be removed under topical anaesthesia by fixing it with a forceps through the conjunctiva and opening it and grasping the worm with a second forceps. According to our experience the paralyzation with Pilocarpine cannot be realized. Careful systemic therapy avoiding reported allergic side effects with Hetrazan which is not available in Germany is necessary.

Severe ocular trauma managed with primary pars plana vitrectomy and silicone oil.

PURPOSE: This study evaluated the outcome of severely injured eyes treated with early primary vitrectomy with silicone oil filling. METHODS: A total of 435 eye injuries, which required surgical intervention, were reviewed retrospectively. In 13 eyes (3%) pars plana vitrectomy and silicone oil filling were performed as primary surgical repair. Silicone oil filling was restricted to cases with laceration of the retina larger than 4 disc diameters (nine eyes), primary retinal detachment larger than two quadrants (two eyes) and/or persistent intrasurgical hemorrhage (12 eyes). All patients underwent surgery within 24 hours. RESULTS: After a mean follow-up period of 28.7 months (range, 9-70 months), 11 eyes achieved a visual acuity ranging from 20/25 to 20/200. Silicone oil was removed in 11 of 13 eyes after 5.8 +/- 4.6 months. Recurrent proliferative vitreoretinopathy developed in two eyes. CONCLUSIONS: Silicone oil tamponade after early primary pars plana vitrectomy may be an alternative for primary repair after trauma, especially in severely injured eyes with retinal lacerations larger than 4 disc diameters, persistent intrasurgical bleeding, and/or primary retinal detachments.

The development of subretinal microphotodiodes for replacement of degenerated photoreceptors.

There are presently several concepts to restore vision in blind or highly visually handicapped persons by implanting electronic devices into the eye in order to partially restore vision. Here, the approach to replace retinal photoreceptors by a subretinally implanted microphotodiode array (MPDA) is summarized. A survey is given on the present state of the development of MPDAs, the possibility of in vitro and in vivo tests as well as first results on biocompatibility and histology. Additionally, electrophysiological recordings in rabbits and rats are presented which have received such subretinal implants.

[Treatment of recurrent corneal erosion using phototherapeutic keratectomy with the excimer laser]. / Die Behandlung der rezidivierenden Erosio corneae mittels phototherapeutischer Keratektomie mit dem Excimer-Laser.

BACKGROUND: Recurrent corneal erosion is a common corneal disease and may be a difficult disorder to treat with a number of patients suffering persistent symptoms despite conventional therapy. PATIENTS AND METHODS: We present a series of 32 eyes who underwent Excimer-Laser phototherapeutic keratectomy (PTK) for recurrent corneal erosion. There were 11 eyes who were treated during an acute episode of recurrent erosion. All remaining patients were treated in a symptom-free interval. The affected area of epithelium was removed and a 25 pulse ablation was performed to Bowman's membrane. RESULTS: In 30 eyes there was a marked improvement in symptoms postoperatively with no recurrences. However, 2 eyes experienced a recurrent episode 6 days and 2 weeks after PTK, respectively. Postoperative refraction and corneal topography was unaltered in all cases. CONCLUSIONS: Excimer-Laser PTK appears to be a safe and promising procedure for recurrent corneal erosion in cases refractory to medical treatment.