Main Principles of Vitrectomy Using Intraocular Tamponades - A Basic Course in Surgery. / Grundlagen der Vitrektomie unter Verwendung intraokularer Tamponaden ­ ein chirurgischer Basiskurs.

This article is intended to clearly present the basic principles for the use of intraocular tamponades in vitreous/retinal surgery in the event of retinal detachment and other pathologies using additional video footage. It examines the various gases, silicone oils and perfluorocarbon liquids with their indications, administration and in particular intraoperative handling including pitfalls and complications. Characteristic animations show the principles of use in surgery in a comprehensible way. The two lead authors dedicate this article to their teacher Prof. Dr. V.-P. Gabel, who in the early 1990s successfully established the first vitrectomy courses for ophthalmologists at Regensburg University Eye Clinic each year. Many colleagues who still work in retinal surgery today first started learning about this segment on these courses. The other coauthors participated under his supervision in annual vitrectomy wet labs run by the German Academy of Ophthalmology.

Spatial resolution and perception of patterns mediated by a subretinal 16-electrode array in patients blinded by hereditary retinal dystrophies.

PURPOSE: The perception of 11 persons blinded by hereditary retinal degeneration elicited by a subretinally implanted 16-electrode array used for light-independent direct stimulation of the retina is described. This device is part of the Tübingen retina implant, which also employs a light-sensitive, multiphotodiode array (MPDA). The ability to reliably recognize complex spatial percepts was investigated. METHODS: Eleven blind volunteers received implants and participated in standardized psychophysical tests investigating the size and shape of perceptions elicited by single-electrode activation, multiple-electrode activation, and activation of compound patterns such as simplified letters. RESULTS: Visual percepts were elicited reliably in 8 of 11 patients. On single-electrode activation, percepts were generally described as round spots of light of distinguishable localization in the visual field. On activation of a pattern of electrodes, percepts matched that pattern when electrodes were activated sequentially. Patterns such as horizontal or vertical bars were identified reliably; the most recent participant was able to recognize simplified letters presented on the 16-electrode array. The smallest distance between sites of concurrent retinal stimulation still yielding discernible spots of light was assessed to be 280 µm, corresponding to a logMAR of 1.78. CONCLUSIONS: Subretinal electric stimulation can yield reliable, predictable percepts. Patterned perception is feasible, enabling blind persons to recognize shapes and discriminate different letters. Stimulation paradigms must be optimized, to further increase spatial resolution, demanding a better understanding of physical and biological effects of single versus repetitive stimulation (ClinicalTrials.gov number, NCT00515814).

Different collagen types define two types of idiopathic epiretinal membranes.

AIMS: To identify differences in extracellular matrix contents between idiopathic epiretinal membranes (IEM) of cellophane macular reflex (CMRM) or preretinal macular fibrosis (PMFM) type. METHODS AND RESULTS: Idiopathic epiretinal membranes were analysed by light and quantitative transmission electron microscopy, immunohistochemistry and Western blotting. Substantial differences between CMRM and PMFM were observed regarding the nature of extracellular fibrils. In CMRM the fibrils were thin, with diameters between 6 and 15 nm. Between the fibrils, aggregates of long-spacing collagen were observed. In PMFM the diameters of fibrils measured either 18-26 or 36-56 nm. Using immunogold electron microscopy, 6-15 nm fibrils in CMRM were labelled for collagen type VI, while the fibrils in PMFM remained unstained. Using Western blotting and immunohistochemistry, a strong signal for collagen type VI was observed in all CMRM, while immunoreactivity was weak or absent in PMFM. In contrast, PMFM showed immunoreactivity for collagen types I and II, which was weak or absent in CMRM. Both types of membranes showed immunoreactivity for collagen types III and IV, laminin and fibronectin with similar intensity. CONCLUSION: The presence of high amounts of collagen type VI in CMRM and the relative absence of collagen types I and II is the major structural difference to PMFM.

Subretinal electronic chips allow blind patients to read letters and combine them to words.

A light-sensitive, externally powered microchip was surgically implanted subretinally near the macular region of volunteers blind from hereditary retinal dystrophy. The implant contains an array of 1500 active microphotodiodes ('chip'), each with its own amplifier and local stimulation electrode. At the implant's tip, another array of 16 wire-connected electrodes allows light-independent direct stimulation and testing of the neuron-electrode interface. Visual scenes are projected naturally through the eye's lens onto the chip under the transparent retina. The chip generates a corresponding pattern of 38 × 40 pixels, each releasing light-intensity-dependent electric stimulation pulses. Subsequently, three previously blind persons could locate bright objects on a dark table, two of whom could discern grating patterns. One of these patients was able to correctly describe and name objects like a fork or knife on a table, geometric patterns, different kinds of fruit and discern shades of grey with only 15 per cent contrast. Without a training period, the regained visual functions enabled him to localize and approach persons in a room freely and to read large letters as complete words after several years of blindness. These results demonstrate for the first time that subretinal micro-electrode arrays with 1500 photodiodes can create detailed meaningful visual perception in previously blind individuals.

The outcome of early surgical repair with vitrectomy and silicone oil in open-globe injuries with retinal detachment.

PURPOSE: To determine the functional and anatomic outcome of early surgical repair with vitrectomy and silicone oil in open-globe injuries with retinal detachment (RD). DESIGN: Retrospective consecutive interventional case series. METHODS: All patients with open-globe injuries with RD treated between 1997 and 2007 underwent primary repair including vitrectomy with silicone oil within 8 hours after presentation. For data analysis, patients were divided into 3 groups according to the BETT classification: Group 1, intraocular foreign body; Group 2, penetrating injury; Group 3, globe rupture. Outcome measures were final reading visual acuity (0.4 logMAR or better), final ambulatory visual acuity (1.6 logMAR or better), endophthalmitis, and postoperative proliferative vitreoretinopathy (PVR). RESULTS: Eighty-eight patients were included (Group 1, n = 13; Group 2, n = 36; Group 3, n = 39). Mean follow-up was 22 months (standard deviation [SD] = 23, range 6-107 months). Eight percent of patients retained reading vision without significant difference between the 3 groups. Fewer patients in Group 3 than in Group 1 or 2 retained ambulatory visual acuity (Group 1, 62%; Group 2, 64%; Group 3, 33%, P = .024). Endophthalmitis occurred in 3.4% of eyes (1 eye in each group). PVR grade B-C, type 1-3 developed in 44% of patients without significant difference between the 3 groups. Re-RD occurred in 38% of eyes. CONCLUSIONS: Few patients achieved reading vision while 50% of patients retained ambulatory visual acuity. Final visual outcome is related to the severity of the injury. The frequency of postoperative endophthalmitis is low. Postoperative development of advanced PVR is avoided in most patients.

Management of submacular hemorrhage with intravitreal versus subretinal injection of recombinant tissue plasminogen activator.

AIM: To compare the efficacy of pars plana vitrectomy (ppV) with intravitreal injection of recombinant tissue plasminogen activator (rtPA) and gas versus ppV with subretinal injection of rtPA and intravitreal injection of gas. METHODS: Nonrandomized, retrospective, interventional, comparative consecutive series including 47 patients with submacular hemorrhage. Eighteen patients were treated with ppV, intravitreal injection of rtPA and 20% SF6 gas [group A: mean age 78 years, mean duration of symptoms 6.6 days, 15 age-related macular degeneration (AMD), three retinal arterial macroaneurysm (RAMA)]. Twenty-nine patients were treated with ppV, subretinal injection of rtPA and intravitreal injection of SF6 gas (group B: mean age 75 years, mean duration of symptoms 5.9 days, 26 AMD, two RAMA, one blunt ocular trauma). The main outcome measure was complete displacement of submacular hemorrhage from the fovea. RESULTS: Complete displacement of submacular hemorrhage was achieved in less patients in group A (22%) than in group B (55%) (p = 0.025). In group A, mean best-corrected visual acuity (BCVA) change was logMAR -0.14, standard deviation (SD) = 0.64, and in group B logMAR -0.32, SD = 0.68 without statistically significant difference between the two groups (p = 0.2, Mann-Whitney test). Complications (retinal detachment, vitreous hemorrhage, and recurrence of submacular hemorrhage) were more frequent in group B than in group A. CONCLUSION: ppV with subretinal injection of rtPA and intravitreal injection of gas was more effective than ppV with intravitreal injection of rtPA and gas in terms of complete displacement of submacular hemorrhage; however, it may be associated with a higher rate of postoperative complications. Functional improvement in the majority of patients suggests the absence of direct retinal toxicity of subretinally applied rtPA.

Maintenance of adult porcine retina and retinal pigment epithelium in perfusion culture: characterisation of an organotypic in vitro model.

The purpose of this study was to characterise an ex-vivo adult porcine retina-retinal pigment epithelium (RPE) perfusion organ culture model. Fresh porcine full-thickness retina-RPE-choroid tissue samples were clamped into tissue carriers and mounted in two-compartment containers. The retinal and choroidal sides were continuously perfused with culture medium. pO(2), [Na(+)], [K(+)], [Cl(-)], [glucose], [lactate], and pH were measured in the medium. Tissue samples were examined after 24h, 4, 7, and 10 days in culture. The morphology of the retina and the RPE was examined by light and electron microscopy (LM, EM). The retinal cellular integrity was further examined by immunohistochemistry (Ki 67, GFAP, rhodopsin, synaptophysin, syntaxin, NF 200, TUNEL-test). Fresh porcine full-thickness retina-RPE-choroid tissue samples and tissue samples in static organ culture served as controls. LM, EM, and immunohistochemistry showed intact retinal and RPE cytoarchitecture kept in perfusion culture. Photoreceptor outer segments showed first signs of degeneration after 24h, significant signs of apoptosis and necrosis appeared in the retina after 4 days in perfusion culture. Control tissue samples kept in static culture showed disintegration of the retinal cytoarchitecture after 4 days in culture. The data show that adult porcine retina-RPE tissue can be maintained morphologically intact in perfusion organ culture for at least 10 days. Although first signs of degeneration set in after 24h the structural preservation of the tissue in perfusion organ culture is superior to that in static culture. The perfusion culture model of the retina refines organotypic in vitro test systems and may help to reduce the number of necessary animal experiments in retina and RPE research. It offers new perspectives for the safety testing of substances designed for intraocular application.

Long-term safety and functional outcome of combined pars plana vitrectomy and scleral-fixated sutured posterior chamber lens implantation.

PURPOSE: To investigate the complication profile and the long-term functional outcome of combined pars plana vitrectomy and scleral-fixated sutured posterior chamber lens (PC IOL) implantation. DESIGN: Retrospective, consecutive, interventional case series. METHODS: The records of 63 patients (mean age, 67.5 years) were reviewed retrospectively (follow-up, 12 to 132 months; mean, 43.5 months). The underlying ocular pathologic features; the intraoperative, early (within two weeks after surgery), and late complications (more than two weeks after surgery); final best-corrected visual acuity (BCVA); and the refractive outcome were recorded. RESULTS: Fifty-nine of 63 procedures (93.7%) were performed without complications. Intraoperative complications included vitreous hemorrhage (n = 2), a retinal tear (n = 1), and a rupture of the iris base (n = 1). Early complications included transient raise of intraocular pressure (IOP; n = 19), transient vitreous hemorrhage (n = 2), scleral tunnel insufficiency (n = 5), pupillary capture of intraocular lens [IOL] (n = 6), persistent vitreous (n = 3), and choroidal hemorrhage (n = 1). Late complications occurred in 12 patients: rhegmatogenous retinal detachment (n = 4), proliferative vitreoretinopathy retinal detachment secondary to the underlying ocular pathologic features (n = 2), choroidal hemorrhage (n = 1), macular pucker (n = 1), and IOL dislocation (n = 4), including two cases of suture break. Mean BCVA in logarithm of the minimum angle of resolution units improved significantly from 1.025 (standard deviation [SD], 0.654) to 0.766 (SD, 0.750; P = .03). Mean cylindric equivalent significantly changed from 0.92 diopters (D; SD, 1.075) to 1.76 D (SD, 1.344; P = .005). CONCLUSIONS: The surgical procedures were performed safely in approximately 94% of patients. Most postoperative complications were minor: significant ones occurred in approximately 20%, whereas suture breaks were observed rarely. The only moderate long-term functional improvement in this case series was mainly determined by the underlying ocular pathologic features.

Retreatment of full-thickness macular hole: predictive value of optical coherence tomography.

AIM: To determine whether the efficacy of re-operation for idiopathic full-thickness macular hole (FTMH) remaining open after initial surgery with internal limiting membrane (ILM) peeling is correlated with macular hole configuration as determined by optical coherence tomography (OCT), macular hole size, macular hole duration before the first operation, or type of tamponade (gas or silicone oil). METHODS: A retrospective consecutive interventional case series of 28 patients (28 eyes) with a persisting macular hole after vitrectomy, ILM peel, and gas tamponade. 28 patients underwent repeat surgery involving vitrectomy and gas (n = 15) or silicone oil tamponade (n = 12) or no tamponade (n = 1). Autologous platelet concentrate (n = 22), autologous whole blood (n = 1), or no adjuvant (n = 5) was used. Preoperative OCT was undertaken in all eyes. The main outcome measures were anatomical closure and improvement of best-corrected visual acuity (BCVA). RESULTS: Anatomical closure was achieved in 19 of 28 eyes (68%). BCVA improved in 12 eyes, remained unchanged in nine, and worsened in seven. BCVA improved in 11 of 19 eyes with anatomical closure, and in one of eight eyes without closure. Anatomical closure and improvement of BCVA correlated with preoperative macular hole configuration on OCT, with higher rates of closure (18 of 20 eyes versus one of eight eyes, p = 0.001) and greater improvement of BCVA (p = 0.048) in eyes with a cuff of subretinal fluid at the break margin. Macular hole size, type of tamponade, macular hole duration before the first operation, or preoperative BCVA did not significantly correlate with visual or anatomical outcome. CONCLUSION: Macular hole configuration seems to be a strong prognostic indicator of anatomical closure and may help identify those patients most likely to benefit from re-operation.

Ascorbic acid modulates proliferation and extracellular matrix accumulation of hyalocytes.

Ascorbic acid is known to influence proliferation and functional properties of several cell types and is therefore widely used in tissue engineering. In this study, the effect of ascorbic acid on the proliferation and functional properties of hyalocytes was evaluated. Hyalocytes were cultured with different amounts of ascorbic acid in classical two-dimensional (2-D) cultures and a three-dimensional (3-D) pellet culture system. Ascorbic acid enhanced hyalocyte proliferation dose-dependently at concentrations between 0.1 and 3 microg/mL; proliferation was constant over a wide concentration range up to 150 microg/mL, concentrations of 500 microg/mL showed toxic effects. In 2-D hyalocyte culture, the accumulation of glycosaminoglycans (GAG) and collagens increased in response to ascorbic acid supplementation of 10 or 200 microg/mL. Normalized to the cell number, GAG production was not influenced, whereas collagen production increased. These results could be verified in a pellet-like 3-D culture system. Ascorbic acid also influenced hyalocytes on the mRNA level; the expression of COL11A1 was clearly enhanced by ascorbic acid. To conclude, ascorbic acid modulates proliferation and collagen accumulation of hyalocytes; it also influences mRNA expression of the cells. Taken together with the fact that ascorbic acid is present in high concentrations in the vitreous body, this vitamin seems to be an important factor for in vitro hyalocyte culture.

Surgical removal of idiopathic epiretinal membrane with or without the assistance of indocyanine green: a randomised controlled clinical trial.

PURPOSE: To carry out a prospective investigation of the functional and morphological outcome of idiopathic epiretinal membrane (IEM) surgery with or without the assistance of indocyanine green (ICG) in a randomised controlled clinical trial. METHODS: Sixty patients who underwent vitrectomy with removal of IEM combined with cataract surgery were randomly allocated to two groups: 27 patients were operated on with ICG 0.1% in glucose 5%, 33 patients without ICG. Functional outcome was assessed 3-4 months postoperatively with improvement of best-corrected visual acuity (BCVA), Amsler grid test, and automated and kinetic perimetry. Postoperative residual or recurrent IEM was assessed with bio-microscopy, and macular oedema with optical coherence tomography (OCT). Improvement in BCVA was the main outcome measure. RESULTS: BCVA improved in 49 patients, remained unchanged in five and decreased in five. Improvement in BCVA and reduction of macular oedema were statistically significant within both groups (P < 0.01). Improvement in BCVA was not statistically significantly different whether ICG was used or not [0.17 (logarithm of minimum angle of resolution; logMAR) with ICG and 0.24 (logMAR) without ICG] (P = 0.59). There was no statistically significant difference in preoperative or postoperative BCVA, reduction of macular oedema, postoperative Amsler grid test, or incidence of residual or recurrent IEM between the two groups. Visual field defects were detected in two patients operated on with ICG. CONCLUSIONS: Removal of IEM with or without the assistance of ICG equally improved visual function and macular morphology.

Optical coherence tomography findings in idiopathic juxtafoveal retinal telangiectasis.

PURPOSE: To describe optical coherence tomography (OCT) findings in patients with juxtafoveal retinal telangiectasis (JRT). METHODS: Fourteen consecutive patients (28 eyes) with JRT (12 patients with JRT type II, one with JRT type I and one with JRT type III) were examined using fluorescein angiography (FA) and OCT. RESULTS: Despite prominent leakage in FA, macular oedema was absent in all 26 eyes with type II JRT. In contrast to that, in patients with type I and type III JRT, cystoid macular oedema was evident. In 14 of 28 eyes (all with type II JRT), a single foveal cyst was found in OCT. It varied significantly in size and was associated with visual acuity decrease. An intraretinal hyperreflective lesion was seen in eight of 28 eyes and flattening of the fovea in three eyes. CONCLUSIONS: Foveal cyst, absent macular oedema, intraretinal hyperreflective lesions and foveal flattening were the most common OCT findings in patients with JRT type II. These may represent progressive loss of retinal tissue, possibly due to Müller cells degeneration, and provide additional diagnostic criteria for JRT.

Keratocyte density in the retroablation area after LASEK for the correction of myopia.

PURPOSE: During excimer laser photoablation keratocyte cell death is induced in the retroablation area. Afterwards this area is repopulated by keratocyte mitosis and migration from the adjacent stroma. The aim of this study was to investigate keratocyte density in the retroablation area and in the posterior stroma during the first year after LASEK for the correction of myopia. METHODS: In a prospective study LASEK surgery was performed in 17 eyes of 10 consecutive patients for the correction of myopia (-2.25 D to -9.0 D, mean -5.0 D). Confocal microscopy (Nidek Confoscan 2) was performed before surgery and 1 month, 3 months, 6 months and 12 months after LASEK. Keratocyte density was assessed in the anterior retroablation area at depths of 5 mum and 25 mum and in the posterior stroma at distances of 5 mum and 100 mum from the corneal endothelium and compared with the corresponding area before surgery. RESULTS: Keratocyte density was statistically significant reduced in the retroablation area at all timepoints after LASEK. At a depth of 5 mum, cell densities were decreased by 64%, 47%, 43%, and 28% at 1 month, 3 months, 6 months and 12 months after LASEK compared with preoperative values. At a depth of 25 mum, cell densities were decreased by 51%, 32%, 28%, and 18% at 1 month, 3 months, 6 months and 12 months after LASEK compared with preoperative values. In the posterior stroma no significant change in keratocyte density was observed at any time after LASEK. CONCLUSIONS: Keratocyte density in the anterior retroablation area recovers during the first year after LASEK for the correction of myopia, but does not go back to preoperative values.

Safety testing of indocyanine green in an ex vivo porcine retina model.

PURPOSE: To assess retinal toxicity of indocyanine green (ICG) in a porcine ex vivo perfusion organ culture model, and to measure intraretinal penetration of ICG applied to the retinal surface. METHODS: The retinal surface of fresh porcine retinal tissue was exposed to ICG 0.1% and 1% dissolved in glucose 5% for 1 and 30 minutes with and without concomitant illumination. Specimens were then kept in perfusion organ culture for 24 hours before examination by light microscopy and the TUNEL technique. Tissue samples treated with DNAse served as positive controls, and samples exposed to saline served as negative controls. Fluorescence microscopy was used to localize ICG at 1 minute, 60 minutes, 2 hours, and 3 hours after a 1-minute exposure of the retinal surface to ICG 1%. RESULTS: No increase in TUNEL-positive cells was observed after exposure to ICG 0.1% for 1 minute. Moderate apoptosis was found after 1-minute exposure to ICG 1% and 30-minute exposure to ICG 0.1%, and severe apoptosis was found after 30-minute exposure to ICG 1%. Concomitant application of light did not influence the degree of apoptosis. No signs of cell necrosis were found. After 1-minute exposure of the retinal surface, ICG 1% gradually penetrated the entire retina. CONCLUSIONS: ICG induced apoptosis but not necrosis in all nuclear retinal layers in a dose-dependent manner. Brief exposure to ICG 0.1% for 1 minute and illumination for 3 minutes simulated the intraoperative use of ICG. No retinal apoptosis or necrosis was observed. ICG briefly applied to the retinal surface gradually penetrated the entire retina.

Fundus autofluorescence before and after photodynamic therapy for choroidal neovascularization secondary to age-related macular degeneration.

BACKGROUND AND OBJECTIVE: To describe fundus autofluorescence patterns in choroidal neovascularization secondary to age-related macular degeneration before and after photodynamic therapy (PDT). PATIENTS AND METHODS: Sixty-eight consecutive eyes were indicated for PDT after standard fluorescein angiography, which showed completely classic choroidal neovascularization (CNV) (n=52), occult with no classic CNV (n=7), and predominantly classic CNV (n=9). Standardized PDT was performed and patients were examined 2 to 3 months later. Angiography and autofluorescence measurements were performed again and compared with preoperative values. RESULTS: At baseline, autofluorescence was mainly decreased in areas of completely classic CNV (79%), but showed a regular or mottled pattern in occult CNV. A slightly increased (50%) or normal (50%) autofluorescence was seen at the rim of the classic lesions within the junctional zone. Membrane demarcation was improved (90%) in classic membranes 2 to 3 months after PDT. After PDT for occult membranes, a transformation into classic membranes with residual leakage and need for further PDT was observed (6 of 7 eyes), showing the described autofluorescence patterns. For the mixed type of CNV, both described patterns of autofluorescence distribution were found. CONCLUSION: Especially classic CNVs reveal distinct characteristics of significantly decreased autofluorescence, presumably due to their localization above the retinal pigment epithelium level, leading to blockage of autofluorescence. Autofluorescence patterns after PDT included enhanced demarcation of the membrane, suggesting reactive retinal pigment epithelial changes. Autofluorescence might be an interesting tool to distinguish noninvasively between classic and occult CNV in age-related macular degeneration and to monitor changes after PDT.

Correlation between optical coherence tomography and autofluorescence in acute posterior multifocal placoid pigment epitheliopathy.

PURPOSE: To report a case of bilateral acute posterior multifocal placoid pigment epitheliopathy (APMPPE) evaluated by optical coherence tomography (OCT), fundus autofluorescence (AF) and microperimetry, both in the acute phase and after resolution of symptoms. METHODS: Complete ophthalmological evaluation, including fluorescein angiography, OCT, AF, and microperimetry upon presentation and 1 month later, after lesions have subsided. An attempt to correlate the findings on presentation and changes after resolution is performed using the results of these new investigational techniques. RESULTS: APMPPE showed hyperreflectance in OCT at the level of the outer retinal layers, without increase in retinal thickness. AF revealed early decreased fluorescence due to a masking effect, and later reveals increased fluorescence after resolution of OCT findings. Function is disturbed at the lesion sites, as shown by microperimetry, and later returns to near normal values on microperimetry. CONCLUSION: APMPPE shows outer retinal layers changes on OCT, which resolve totally after subsidence of the acute phase. AF shows areas of increased fluorescence after resolution, with near normal return of function on microperimetry.

Preferential Hyperacuity Perimeter (PreView PHP) for detecting choroidal neovascularization study.

PURPOSE: To assess the ability of the Preferential Hyperacuity Perimeter (PreView PHP; Carl Zeiss Meditec, Dublin, CA) to detect recent-onset choroidal neovascularization (CNV) resulting from age-related macular degeneration (AMD) and to differentiate it from an intermediate stage of AMD. DESIGN: Prospective, comparative, concurrent, nonrandomized, multicenter study. PARTICIPANTS: Eligible participants' study eyes had a corrected visual acuity of 20/160 or better and either untreated CNV from AMD diagnosed within the last 60 days or an intermediate stage of AMD. METHODS: After obtaining consent, visual acuity with habitual correction, masked PHP testing, stereoscopic color fundus photography, and fluorescein angiography were performed. Photographs and angiograms were evaluated by graders masked to diagnosis and PHP results. The reading center's diagnosis determined if the patient was categorized as having intermediate AMD or neovascular AMD. MAIN OUTCOME MEASURES: A successful study outcome was defined a priori as a sensitivity of at least 80% and a specificity of at least 80%. RESULTS: Of 185 patients who gave consent to be enrolled, 11 (6%) had PHP results judged to be unreliable. An additional 52 were not included because they did not meet all eligibility criteria. Of the remaining 122 patients, 57 had an intermediate stage of AMD and 65 had neovascular AMD. The sensitivity to detect newly diagnosed CNV using PHP testing was 82% (95% confidence interval [CI], 70%-90%). The specificity to differentiate newly diagnosed CNV from the intermediate stage of AMD using PHP testing was 88% (95% CI, 76%-95%). CONCLUSIONS: Preferential Hyperacuity Perimeter testing can detect recent-onset CNV resulting from AMD and can differentiate it from an intermediate stage of AMD with high sensitivity and specificity. These data suggest that monitoring with PHP should detect most cases of CNV of recent onset with few false-positive results at a stage when treatment usually would be beneficial. Thus, this monitoring should be considered in the management of the intermediate stage of AMD.

[The influence of ionizing radiation on the development of posterior capsule opacification in vitro]. / Der Einfluss ionisierender Strahlen auf die Entwicklung der Sekundärkatarakt in vitro.

BACKGROUND AND PURPOSE: Histologically, the posterior capsule opacification (PCO) corresponds to regenerative tissue of transformed lens epithelial cells (LECs) with extracellular matrix production. In this study, the influence of ionizing radiation on proliferating LECs and the development of PCO was investigated in vitro. MATERIAL AND METHODS: Each four and 14 pork lenses, respectively, were irradiated with 6 MeV electrons with single doses of 8, 10, 12, and 20 Gy. 1-2 h after irradiation the lens was removed by capsulorrhexis and hydrodissection. After fixation of the capsular bag in a special device the proliferation of residual LECs was examined daily. The experiment was considered to be finished when the capsular bag was completely opacified by confluent cell proliferates. RESULTS: Single dose irradiation with electrons in a dose range from 8 to 12 Gy significantly protracted the development of PCO with complete inhibition of PCO after application of 20 Gy. CONCLUSION: To inhibit PCO in vitro, a single dose of 20 Gy is necessary. The actual in vitro model allows an optimal investigation of PCO formation under different external influences and is therefore very suitable for radiobiological questions.

Von Willebrand's disease type I as a cause for subvitreal, retinal and subretinal haemorrhages.

BACKGROUND: Young patients with vitreous, retinal and subvitreal haemorrhages without neovascularisation or prior trauma are a diagnostic challenge for the physician. In this case report, a patient is presented who developed unilateral, spontaneous, subvitreal, retinal and subretinal haemorrhages and was diagnosed with von Willebrand's disease. CASE REPORT: A 33-year-old Caucasian woman presented at our clinic with unilateral subvitreal, retinal and subretinal haemorrhages. The haemorrhages occurred spontaneously without prior trauma, and the patient had no history of prior bleeding complications. Analysis of the coagulation-fibrinolysis system and von Willebrand multimer analysis led to the diagnosis von Willebrand's disease type I. CONCLUSIONS: Spontaneous subvitreal, retinal and subretinal haemorrhages may be associated with coagulation disorders. Especially in young patients, von Willebrand's disease should be considered as a possible cause.