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report no. 7. Nicolas Feltgen,1 Heinrich Heimann,2 Hans Hoerauf,1 ... Key words: anatomical result – primary vitrectomy – rhegmatogenous retinal detachment.
Acta Ophthalmologica 2013

Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment study (SPR study): Risk assessment of anatomical outcome. SPR study report no. 7 Nicolas Feltgen,1 Heinrich Heimann,2 Hans Hoerauf,1 Peter Walter,3 Ralf-Dieter Hilgers4 and Nicole Heussen4 On behalf of Writing group for the SPR study investigators* 1

Department of Ophthalmology, Georg-August University Hospital, Goettingen, Germany 2 St. Paul’s Eye Unit, Royal Liverpool University Hospital, Liverpool, UK 3 Department of Ophthalmology, University Hospital, Aachen, Germany 4 Department of Medical Statistics, RWTH Aachen University, Aachen, Germany

ABSTRACT. Purpose: The ‘Scleral buckling versus primary vitrectomy in rhegmatogenous retinal detachment study’ (SPR study) is a randomized multicentre trial comparing primary vitrectomy (PV) and scleral buckling surgery (SB) for rhegmatogenous retinal detachment (RRD). This subanalysis was conducted to identify risk factors associated with anatomical outcomes. Methods: Relating the anatomical success results at the 1-year follow-up visit to pre- and intraoperative findings using multivariate statistical methods. Results: In the phakic subtrial, anatomical success was negatively associated with the number of breaks (p < 0.0001), break extension > 1 clock hour (p = 0.0005) and intraoperative use of cryotherapy (p = 0.0484). It was positively associated with retinal breaks with irregular edges (p = 0.0353) and subretinal fluid drainage (p = 0.0155). In the pseudophakic ⁄ aphakic subtrial, anatomical success was negatively associated with the number of retinal breaks (p = 0.0004) and previous YAG capsulotomy (p = 0.0256), and the combined effect of the surgical procedure and intraoperative use of laser (p = 0.0229). Conclusion: Primary anatomical success is an important result for patients undergoing RRD surgery. Our data demonstrate that the final anatomical outcome is related to a higher preoperative number of breaks and cryotherapy in phakic eyes. Additional risk factors varied between phakic and pseudophakic subgroups. Our findings may be used to facilitate the prognosis of future patients with RRD. Key words: anatomical result – primary vitrectomy – rhegmatogenous retinal detachment surgery – scleral buckling

Acta Ophthalmol. 2013: 91: 282–287 ª 2012 The Authors Acta Ophthalmologica ª 2012 Acta Ophthalmologica Scandinavica Foundation

doi: 10.1111/j.1755-3768.2011.02344.x

Introduction The ‘Scleral buckling versus primary vitrectomy in rhegmatogenous retinal

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detachment designed to (SB) versus in primary

study’ (SPR study) was compare scleral buckling primary vitrectomy (PV) rhegmatogenous retinal

detachment (RRD) of medium complexity (Heimann et al. 2001; Feltgen et al. 2007; Heimann et al. 2007). It was a prospective, randomized multicentre clinical trial in which numerous pre-, intra- and postoperative characteristics were documented according to the study protocol. Many groups have tried to identify prognostic factors for anatomical results after retinal detachment surgery. The most commonly identified preoperative factors are preoperative proliferative vitreoretinopathy (PVR), extension of retinal detachment, number of preoperative retinal breaks, lower intraocular pressure (IOP) and postoperative PVR, all of which seem to influence anatomical outcome (Ahmadieh et al. 2000; Ranta & Kivela 2002; Afrashi et al. 2005; Halberstadt et al. 2005; Rodriguez de la Ru´a et al. 2005; Pastor et al. 2008; Heussen et al. 2011a,b). In this study, we analysed this comprehensive data set to generate a secondary analysis of predictive factors for successful anatomical outcome. The novel aspect of our analysis is the simultaneous assessment of pre- and

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intraoperative findings for predicting anatomical outcome after 1 year in a well-defined disease such as primary RRD of medium complexity. In addition, our analysis distinguishes between phakic and pseudophakic patients according to the study design in two separate study subgroups.

Table 1. Surgery-related findings collected from case report forms.

Material and methods

Previous treatment prior to surgery

Lens status

Phakic

Pseudophakic ⁄ Aphakic

General data Presence of symptoms prior to surgery

Age Deterioration in visual acuity Visual field defect Photopsia Mouches volantes Duration of symptoms > 1 week Cryotherapy Photocoagulation

Age Deterioration in visual acuity Visual field defect Photopsia Mouches volantes Duration of symptoms > 1 week Cryotherapy Photocoagulation Cataract surgery Capsulotomy during cataract surgery YAG capsulotomy Secondary cataract ⁄ capsular fibrosis Vitreous opacity ⁄ haemorrhage Macula attached ⁄ detached Number of breaks in the retina Break extension > 1 clock hour Break with elevated flap Break with irregular edges Retinal detachment central to vessel arcades Retinal detachment at buckle ⁄ cerclage posterior capsule damaged Visual acuity category (‡ 1.0 logMAR or < 1.0 logMAR)

SPR study design

The SPR study was designed to compare SB and PV in patients with a primary RRD of medium complexity (Heimann et al. 2001). Institutional Review Board (IRB) ⁄ Ethics Committee approval was obtained at all participating centres. Between August 1998 and June 2003, 45 surgeons in 25 centres in five European countries recruited a total of 416 phakic (209 SB ⁄ 207 PV) and 265 pseudophakic (133 SB ⁄ 132 PV) patients. Informed consent was obtained from each patient. According to the definition of the full analysis set [8], one patient was excluded from analysis because of missing postrandomization data. The study design and general data collection (e.g. inclusion criteria, follow-up time, etc.) have previously been published (Heimann et al. 2001, 2007). For this analysis, we used information regarding the pre- and intraoperative findings from the study’s case report forms as detailed in Table 1 and provided in study report Nr. 6 (Heussen et al. 2011a,b). Additional evaluation

Additional information was extracted from the fundus drawings within the CRF and surgical notes. Because of individual differences in recording fundus drawings and surgical notes, all drawings and notes were reviewed and classified by three vitreoretinal surgeons (H. H., N. F., P. W.) regarding pre- and intraoperative characteristics (Table 2). Whenever the reviewers’ results disagreed, a majority vote (2:1) was taken. In addition to standardized questionnaires, the case report forms for documentation during the trial also included free text surgical reports and fundus drawings of the anatomical situation at baseline and at the end of

Pathologic findings anterior segment Pathologic findings posterior segment

Secondary cataract ⁄ capsular fibrosis Vitreous opacity ⁄ haemorrhage Macula attached ⁄ detached Number of breaks in the retina Break extension > 1 clock hour Break with elevated flap Break with irregular edges Retinal detachment central to vessel arcades Retinal detachment at buckle ⁄ cerclage

Other preoperative findings

Visual acuity category (‡ 1.0 logMAR or < 1.0 logMAR) LOCS III values Additional breaks found Subretinal haemorrhage during surgery Incomplete drainage of subretinal fluid Iatrogenic breaks Subretinal gas Subretinal heavy fluid

Intraoperative findings

Additional breaks found Subretinal haemorrhage during surgery Incomplete drainage of subretinal fluid Iatrogenic breaks Subretinal gas Subretinal heavy fluid Retinal incarceration during surgery

Lens touch during surgery

surgery. These were analysed and recorded in a database by three surgeons to obtain additional information about the anatomical situation and intraoperative findings and manipulations. Outcome variables

All pre- and intraoperative characteristics were investigated in relation to the end-point ‘anatomical success’, defined as ‘retinal reattachment without any retina-affecting reoperation’ at the 1-year visit [2]. Statistical methods

Continuous variables were summarized by means and corresponding standard deviations (SD). Categorical

data were presented by frequencies and percentages. Clinical practise required us to assess missing values as the nonoccurrence of a clinical finding. Logistic regression models were used to analyse the joint relation between our explorative factors (coded by 0 and 1 for binary variables) already mentioned and described in the report Nr. 6 [10] on functional success criteria. First, we checked whether event frequencies (non-event frequencies) in the explanatory subgroup were > 10 (Katz 2003). All exploratory variables were studied in a univariate logistic regression model with surgical procedure and surgeon as immanent factors. To avoid the numerical problem of complete or quasi-complete separation, we

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Table 2. Recording of additional findings extracted from surgical notes and pre-, intra and postoperative fundus drawings. All characteristics classified as present or not present. Clarity of optical media Extension of RRD

Break characteristics

Additional parameters Surgery

Adequate visualisation of retinal periphery Vitreous haemorrhage Superior RRD with breaks between 10 and 2 o’clock position Inferior RRD with breaks between 4 and 8 o’clock position Bullous detachment RRD confined to 1 quadrant Total detachment Central breaks Unusual breaks Multiple breaks, involved area ‡ 3 clock hours Chain formation of breaks Unclear break situation Lattice degeneration Localisation of retinal detachment Use of laser therapy Use of cryotherapy Drainage of subretinal fluid Tamponade

used the estimation methods proposed by Firth (Heinze & Schemper 2002). Exploratory factors were assessed as relevant to be mutually included in our final model if the p-value was below 10% (first step). Relevant effects were studied further for treatment interaction. In doing so, we used the significance margin of 10%. During this final step, we assessed any effect on the model as significant if the corresponding p-value fell below the 5% margin. We report our results by frequencies, odds ratios, corresponding 95% limits of confidence and p-values. All analyses were performed using SAS statistical software, V9.2 (SAS Institute, Cary, NC, USA).

Results Our evaluation is based on fundus drawings and surgical reports of all 680 SPR patients. As defined in the study protocol (Heimann et al. 2001), the analysis is based on the intentionto-treat basis. The surgical procedure was one of the model-building factors as well as the stratification factor ‘surgeon’. Phakic trial – Anatomical success

The results of the phakic subtrial are summarized in Table 3. Primary anatomical success was observed in 265 (64%) of 415 analysed phakic patients. Using the multivariate logistic regression model, anatomical success is related to the number of breaks (p < 0.0001), break extension > 1

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clock hour (p = 0.0005), breaks with irregular edges (p = 0.0353), intraoperative use of cryotherapy (p = 0.0484) and subretinal fluid drainage (p = 0.0155). Mean number of breaks in patients with primary anatomical success was 4 (SD 2), and the mean number without anatomical success was 6 (SD 4). Figure 1 shows the association between the prognostic factors and anatomical success. Pseudophakic trial – Anatomical success

Results of the pseudophakic ⁄ aphakic subtrial are summarized in Table 4. Primary anatomical success was observed in 166 (63%) of 265 analysed pseudophakic patients. The multivariate logistic regression model shows that previous YAG capsuloto-

my (p = 0.0256), number of retinal breaks (p = 0.0004), intraoperative use of laser photocoagulation (p = 0.0113) and interaction between the surgical procedure and intraoperative use of laser (p = 0.0229) were significant predictors (Table 4). The influence of intraoperative laser depends mainly on the surgical procedure, which cannot be interpreted independently. In the PV group, intraoperative use of laser was significantly associated with anatomical success, whereas laser use in the SB group was associated with worse anatomical outcome. The mean number of breaks in patients with primary anatomical success was 2 (SD 2), while the number without anatomical success was 4 (SD 3). Figure 2 shows the association between the prognostic factors and anatomical success.

Discussion Rhegmatogenous retinal detachments can be treated with a variety of surgical techniques, but there is no consensus on which method and surgical tools are best for the individual patient. The main outcomes of the SPR study were that in patients with RRD of medium complexity, the choice of surgical technique has a significant impact on the results. In phakic patients, better functional success was achieved with SB, whereas in pseudophakic patients, better anatomical outcomes were achieved with PV (Heimann et al. 2007). In the SPR study, the PV and SB surgical proce-

Table 3. Results of the multivariate logistic regression model in the phakic subtrial. Significance is given if p £ 0.05.

Factor Surgeon SB versus Primary vitrectomy Visual field defect (n ⁄ yes vs n ⁄ no) Mouches volantes (n ⁄ yes vs n ⁄ no) Number of breaks Break extension > 1 clock hour (n ⁄ yes vs n ⁄ no) Break with irregular edges (n ⁄ yes vs n ⁄ no) Additional breaks (n ⁄ yes vs n ⁄ no) Retinal detachment central to vessel arcades (n ⁄ yes vs n ⁄ no) Retinal detachment at buckle ⁄ cerclage (n ⁄ yes vs n ⁄ no) Intraoperative use of cryotherapy (n ⁄ yes vs n ⁄ no) Subretinal fluid drainage (n ⁄ yes vs n ⁄ no)

Anatomical success rates 265 ⁄ 415 133 ⁄ 209 versus 132 ⁄ 206 235 ⁄ 358 versus 30 ⁄ 57 151 ⁄ 224 versus 114 ⁄ 191 46 ⁄ 87 versus 219 ⁄ 328

Wald test p-value 0.6091 0.3756 0.2603 0.1441 < 0.0001 0.0005

95 ⁄ 134 versus 170 ⁄ 281 66 ⁄ 118 versus 199 ⁄ 297 26 ⁄ 52 versus 239 ⁄ 363

0.0353 0.4594 0.3820

52 ⁄ 96 versus 213 ⁄ 319

0.1531

223 ⁄ 360 versus 42 ⁄ 55

0.0484

96 ⁄ 138 versus 169 ⁄ 277

0.0155

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Fig. 1. Association between selected factors and anatomical success (odds ratios in log scale of the multivariate logistic regression model) in the phakic subtrial.

Table 4. Results of the multivariate logistic regression model in the pseudophakic ⁄ aphakic subtrial. SB and PV are related to the defined risk factors. Results in line 2 have to be interpreted together with the laser interaction (line 12). As a result, patients treated by PV and laser have a significantly higher success rate. Significance is given if p £ 0.05. Anatomical success rates 166 ⁄ 265

Factor Surgeon SB versus PV YAG capsulotomy (n ⁄ yes vs n ⁄ no) Macula detached versus attached (n ⁄ yes vs n ⁄ no) Number of breaks Break extension > 1 clock hour (n ⁄ yes vs n ⁄ no) Category of visual acuity ‡ 1.0 logMAR versus < 1.0 Additional breaks (n ⁄ yes vs n ⁄ no) Intraoperative use of laser (n ⁄ yes vs n ⁄ no) Bullous detachment (n ⁄ yes vs n ⁄ no) Lattice degeneration (n ⁄ yes vs n ⁄ no) Interaction SB ⁄ PV with laser use SB * laser use (n ⁄ yes vs n ⁄ no) PV * laser use (n ⁄ yes vs n ⁄ no)

71 ⁄ 133 versus 95 ⁄ 132 43 ⁄ 81 versus 123 ⁄ 184 100 ⁄ 171 versus 66 ⁄ 94 11 ⁄ 22 versus 155 ⁄ 238 107 ⁄ 153 versus 59 ⁄ 112 83 ⁄ 116 versus 83 ⁄ 149 54 ⁄ 68 versus 112 ⁄ 197 28 ⁄ 52 versus 138 ⁄ 213 13 ⁄ 27 versus 153 ⁄ 238

Wald test p-value 0.9474 0.5349 0.0256 0.5667 0.0004 0.1083 0.2221 0.0527 0.0113 0.9174 0.3015 0.0229

0 ⁄ 5 versus 71 ⁄ 128 54 ⁄ 63 versus 41 ⁄ 69

SB, scleral buckling; PV, primary vitrectomy.

dures were standardized according to the surgical techniques, although individual differences still became apparent. These variations were included into this risk factor analysis. A previously published secondary analysis on the surgeon as a factor on outcome results detected a relation to the functional but not anatomical outcome (Heimann et al. 2009). Several studies have investigated the association between pre- and intraoperative findings and anatomical outcome after retinal detachment surgery. The most relevant preoperative factors that have been associated with

anatomical outcome in several studies are the extension of RRD (Ahmadieh et al. 2000), number of retinal breaks (Afrashi et al. 2005), preoperative PVR (Pastor et al. 2008), lens capsule loss and surgical method (Arya et al. 2006; Tuft et al. 2011). In the present investigation, we focused on the primary anatomical success 1 year after initial surgery. We were surprised that only 64% of all phakic patients (64% in the PB and 64% in the PV group) and 63% of all pseudophakic ⁄ aphakic patients (53% SB and 72% PV) matched those criteria (Heimann et al. 2007), as in con-

trast to our findings, there are reports of primary anatomical success rates ranging between 71 and 93% (Arya et al. 2006; D’Amico 2008; Day et al. 2010; Thelen et al. 2010). This difference is a result of our definition of primary anatomical success and ⁄ or the more complex retinal SPR situation. In the SPR study, retinal reattachment was defined as attachment central to the equator at the final follow-up visit without any retina-affecting procedures, that is, postoperative laser photocoagulation, cryopexy, intraocular gas injection, SB or revisional SB, and vitrectomy or revisional vitrectomy including macular pucker surgery; this is a highly restrictive definition. However, our final anatomical success rate resembles those in the literature, as 97% of the phakic patients (97% SB and 97% PV) and 94% of the pseudophakic ⁄ aphakic patients (93% SB and 96% PV) presented an attached retina at the one-final-year follow-up visit. As mentioned earlier, one must also consider how the retinal SPR situation is defined namely as a retinal detachment of medium complexity (Heimann et al. 2001). All uncomplicated retinal detachments, that is, single breaks and ⁄ or a limited retinal detachment, have been excluded from this study. To exclude all confounding factors involving additional surgery and to homogenize our data set, we focussed on patients with primary anatomical success. Few factors were statistically associated with the primary anatomical outcome in both subtrials. Although we can only speculate about an association between individual factors, most of our results are in line with clinical routine. Regardless of the lens status, worse outcome was associated with numerous retinal breaks. The association between multiple retinal breaks and worse anatomical outcome is unsurprising because of the more complex intraoperative situation, and this association was already reported by Afrashi et al. (2005) in SB-treated patients. Pastor et al. (2008) reported worse outcome associated with the extension of retinal detachment but did not report an influence by the number of breaks. Unlike Pastor et al. and Ahmadieh et al., we did not find a significant association between the extension of retinal detachment and anatomical outcome.

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my because of the density in the outer section of the lens. Another well-known discussion arises from the significant and positive association between subretinal fluid drainage and anatomical outcome. We know that scleral buckling surgery combined with subretinal drainage can succeed even without retinopexy (Mahdizadeh et al. 2008). The results in the literature are unfortunately heterogenous and need clarification (Editorial 1975; Leaver et al. 1975). Our data suggest a potential benefit from subretinal fluid drainage in phakic eyes.

Conclusion Fig. 2. Association between selected factors and anatomical success (odds ratios in log scale of the multivariate logistic regression model) in the pseudophakic ⁄ aphakic subtrial.

The negative outcome after cryotherapy has been described in the literature. Intraoperative use of cryotherapy was associated with more postoperative inflammation, proliferative vitreoretinopathy and reduced visual acuity as compared to laser photocoagulation (Veckeneer et al. 2001; van Meurs et al. 2002; Lira et al. 2010). But most studies compared the intraoperative use of cryotherapy to the postoperative use of external photocoagulation as an adjunct to initial buckling surgery. In the present phakic subtrial, 223 of 360 (62%) eyes treated by cryotherapy demonstrated primary anatomical success, whereas 42 of 55 (76%) eyes undergoing a procedure other than cryotherapy had an attached retina after 1 year. Thirty-four of 42 eyes with attached retina were intraoperatively treated by laser photocoagulation, and 8 eyes did not receive any coagulation. We did not analyse the extent of cryotherapy, which could also influence the results. In the pseudophakic PV subgroup, we observed better anatomical results after the use of laser. Fifty-four of 63 (86%) patients undergoing laser photocoagulation had a primary anatomical success, which was significantly superior to those treated without laser (41 of 69 ⁄ 59%). In patients treated without laser, cryotherapy was used in 66 eyes and no retinopexy in three eyes. It was those patients treated by PV in particular who showed more favourable

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anatomical results after the use of laser coagulation. In the SB group, five eyes have been treated by SB and simultaneous external laser photocoagulation. None of those patients showed primary anatomical success. In the present risk factor model, pseudophakic eyes did much better with intraoperative laser photocoagulation. This correlation could explain the better overall anatomical outcome in pseudophakic patients treated by PV as compared to eyes treated by SB. In phakic eyes, a break extension of more than 1 clock hour was associated with reduced anatomical success. This can also be explained by the more complex intraoperative situation. On the other hand, we did not note an association in the pseudophakic subtrial. One of the SPR inclusion criteria was ‘retinal break with irregular edges’ as all retinal breaks besides horseshoe or round hole were defined to be suspicious for worse outcome. Those breaks were, for example, cleft along retinal vessels or two connected horseshoe tears. We can obviously not explain the association between those breaks with irregular edges and a higher anatomical primary success rate in phakic eyes, as we had also anticipated a more complicated situation. Pronounced secondary cataract was associated with worse outcome. This is also in line with the clinical impression, as it is often difficult to visualize the retinal periphery in eyes that have undergone YAG capsuloto-

In our phakic subtrial, anatomical success was negatively associated with numerous retinal breaks, a break extension of more than 1 clock hour and the use of cryotherapy. Anatomical success associated positively with subretinal fluid drainage and breaks with irregular edges. In the pseudophakic subtrial, anatomical success was also negatively associated with numerous retinal breaks and eyes after YAG capsulotomy, while it associated positively with the use of laser coagulation, especially in vitrectomy. These study results may prove to be useful in counselling patients, in surgical strategy planning and by providing useful information for future modifications of surgical technique. Based on these outcomes, future trials addressing RRD surgery should take these risk factors into account when planning prospective studies.

Acknowledgements Ralf-Dieter Hilgers, Department of Medical Statistics, RWTH Aachen University, Pauwelsstr. 30, 52074 (RWTH) Aachen, Germany, has full access to the study data and takes responsibility for its integrity and the accuracy of the data analysis. Results presented at: Meeting of the German Retinological Society, June 2008, Wuerzburg, Germany and meeting of the German Society of Ophthalmology, September 2008, Berlin and September 2009, Leipzig, Germany. Active participants of the SPR study group; Principal investigators: M.H. Foerster, R.-D. Hilgers (W. Lehmacher); Study co-ordinator: C. Weiß; End-

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point committee (alphabetic order): K.U. Bartz-Schmidt, N. Bornfeld, M.H. Foerster, H. Heimann, R.-D. Hilgers, C. Weiß; Advisory board: M.H. Foerster, P. Bauer, K. Lemmen; Biostatisticians and data managers: R.-D. Hilgers, C. Weiß, M. Nodov; Active study surgeons (alphabetic order): K.U. Bartz-Schmidt, S. Binder, S. Bopp, N. Bornfeld, C. Dahlke, F. Faude, M.H. Foerster, W. Friedrichs, V.P. Gabel, J. Garweg, A. Gaudric, W. Go¨bel, S. Grisanti, C. Groenewald, L.L. Hansen, O. Hattenbach, K. Hille, H. Hoerauf, F. Holz, P. Janknecht, J. Jonas, U. Kellner, B. Kirchhof, F. Koch, F. Ko¨rner, H. Laqua, Y. LeMer, M. Lo¨w, A. Lommatzsch, K. Lucke, P. Meier, E. Messmer, U. Mester, M. Partzsch, D. Pauleikhoff, I. Pearce, J. Roider, H. Schilling, W. Schrader, N. Schrage, U. Stolba, P. Walter, B. Wiechens, S. Wolf, D. Wong; Study nurses: N. Alteheld, E. Biewald, L. Garnett, M.A. Macek, G. Ro¨ssler; Local study coordinators: N. Feltgen, M. Go¨k, B. Moustafa, D. Ottenberg, S. Pape, J. Slater. The study was funded by grants from the German Research Foundation, Bonn, Germany (Fo 165 ⁄ 2 -1, -2, -3, -4; Le 842 ⁄ 3 -1, -2; Hi 541 ⁄ 2 -1, -2), ‘Stifterverband of German Science (Friedrich-Spicker-Stiftung)’, Wuppertal, Germany (no. S 050-10.003 ⁄ 004), and the German Retinological Society.

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Received on July 8th, 2011. Accepted on November 3th, 2011. Correspondence: Nicolas Feltgen, MD Department of Ophthalmology Georg-August University Hospital Robert-Koch-Str. 40, 37075 Goettingen Germany Tel: + 49 551 39 6143 Fax: + 49 551 39 6787 Email: [email protected]

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