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.

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.

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.

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.

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.

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.

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.

[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.

Clinical findings on the use of long-term heavy tamponades (semifluorinated alkanes and their oligomers) in complicated retinal detachment surgery.

BACKGROUND: Heavy tamponades for pathologies in the lower part of the retina are a new development, and different tamponades have recently come into clinical use: semifluorinated alkanes (F(6)H(6), F(6)H(8)) and their oligomers (OL62HV). METHOD: Nine patients had been operated on using F(6)H(8) (n=5) and by OL62HV (n=4). In all cases the reasons for using the tamponades were complicated retinal detachments in the lower part. In three cases the use was primary and in six cases tamponades were used after reoperations. In all cases the endotamponade was removed within 6 weeks. Fluorescein angiography (FLA) was performed in the F(6)H(8) group. RESULTS: In the F(6)H(8)group dispersion developed in two of the three aphacic patients. In two out of five cases soft epiretinal membranes and cellular material could be found between the substance and the lower periphery. In two membranes examined by light microscopy, cystic cells and amorphous material could be found. In one case (PDRP, aphacic) cyclophotocoagulation had to be performed because of persistent elevated IOP. FLA was unremarkable. In the OL62HV group, severe recurrent PVR reaction occurred in the lower periphery (2/4) and unusual precipitates were observed (4/4). In one case, after a normal postoperative period (VA 0.05 after 5 days) an extensive cellular reaction on the complete surface of the tamponade occurred. After 5 weeks VA was no light perception. During removal of the oligomer unusual adherent cellular components were found on the surface of the retina. The retina appeared necrotic, showed constricted retinal vessels and there was optic atrophy. Histologically, fluffy epiretinal material and a lens capsule obtained from one eye filled with OL62HV resembled the appearance with F(6)H(8). CONCLUSION: Heavy endotamponades on the basis of semifluorinated alkanes can lead to an unusual biological reaction and need further investigation before clinical use.