Downloaded from http://bjo.bmj.com/ on August 21, 2017 - Published by group.bmj.com Clinical science Prevalence and predictors of metamorphopsia after successful rhegmatogenous retinal detachment surgery: a cross-sectional, comparative study Chuandi Zhou,1 Qiurong Lin,2 Fenge Chen2 1Department of Ophthalmology, ABSTRACT metamorphopsia. In another study, which consisted Ninth People’s Hospital of Aims To evaluate the prevalence of metamorphopsia of 129 RRD patients, 50 (38.76%) cases had meta- Shanghai, Shanghai Jiaotong after successful rhegmatogenous retinal detachment morphopsia after a 6–12-month follow-up.3 For University, Shanghai, China 2Department of Ophthalmology, (RRD) surgery and determine the independent predictors studies that only included macula-off cases, the inci- First People’s Hospital of of metamorphopsia. dence of metamorphopsia was much higher, varying – Shanghai, Shanghai Jiaotong Methods A cross-sectional, comparative study. The from 66.7% to 88.6%.4 7 However, these studies University, Shanghai, China study included 380 eyes of 357 patients who underwent had relatively small sample sizes and short follow-up a successful RRD surgery between 2009 and 2015. The periods. Therefore, they might not capture the true Correspondence to presence of metamorphopsia was tested with an Amsler characteristics of the entire RRD population. Dr Fenge Chen, Department of Ophthalmology, First People’s grid and the foveal microstructure was scanned with The pathophysiology of metamorphopsia is not Hospital of Shanghai, Shanghai high-resolution spectral-domain optical coherence completely understood.38It was generally believed Jiaotong University, 100 tomography (OCT) at a follow-up visit. Medical records to be a symptom of retinal distortion from intrinsic Haining Road, Hongkou District, were reviewed for preoperative and intraoperative factors retinal disease because of poor orientation of photo- Shanghai 200080, China; 9 [email protected] associated with postoperative visual recovery. receptors. Optical coherence tomography (OCT) Results The mean follow-up period was 35.1 has been widely used to detect the abnormal micro- Received 25 May 2016 ±19.6 months. The prevalence of metamorphopsia in structures in relation to metamorphopsia after Revised 22 August 2016 our study was 46.58% (177/380), whereas in macula- RRD surgeries. Dell’Omo et al8 demonstrated that Accepted 28 August 2016 the presence of outer retinal folds was an inde- Published Online First off cases this number increased to 56.69% (144/254). 15 September 2016 Stepwise logistic regression analysis indicated that pendent predictor for metamorphopsia. However, younger age at the diagnosis (OR=0.97, p<0.01), the pathophysiology of metamorphopsia is multifac- preoperative macula-off status (OR=3.34, p<0.01), torial, and their study only included the independ- postoperative presence of subretinal fluid (SRF) ent variables of OCT findings, which had limited (OR=3.58, p=0.01) and disrupted external limiting explanatory effects. Other factors not included in membrane (ELM) junction (OR=1.79, p=0.02) were the that study should also be considered, such as demo- independent predictors for metamorphopsia after graphic and baseline clinical characteristics. surgery. The abnormal foveal microstructures after The purpose of this cross-sectional, comparative successful surgeries mainly included six types: disrupted study was to determine the prevalence of metamor- inner segment/outer segment (133 eyes, 35.00%), phopsia after RRD surgery, and its possible disrupted ELM (131 eyes, 34.47%), epiretinal membrane predictors. (44 eyes, 11.58%), SRF (26 eyes, 6.84%), macular hole (9 eyes, 2.37%) and cystoid macular oedema (6 eyes, METHODS 1.58%). Patients Conclusions Considering metamorphopsia, special The medical records of patients operated for RRDs attention should be paid to young patients and/or the by one surgeon (FC) were reviewed (1006 pat- cases with involvement of macula. High-resolution OCT ients). These patients were admitted to the First is informative in detecting anatomic abnormalities after People’s Hospital of Shanghai from January 2009 RRD surgery. The postoperative presence of SRF and to April 2015. Chart review yielded 678 consecu- disrupted ELM line are independent predictors of tive eyes that had RRDs, which either underwent metamorphopsia. vitrectomy or scleral buckling or a combination of both. The exclusion criteria were (1) prolifera- tive vitreoretinopathy (PVR) worse than grade INTRODUCTION C. Because, first, very few patients had funnel- The success rate of the surgical repair of rhegmato- shaped RRD, and second, the extremely poor post- genous retinal detachment (RRD) is now up to operative visual acuity limited the use of an Amsler 90%.1 However, anatomic reattachment of the grid to test of the presence of metamorphopsia; retina does not always mean recovery of visual (2) other severe vision-impaired eye diseases (eg, function. Metamorphopsia is one of the most uveitis, glaucoma or trauma), especially involving common postoperative complaints. the macula (eg, macula hole, epiretinal membrane Reports are emerging in the literature about meta- (ERM), cystoid macula oedema (CMO), age-related morphopsia after successful RRD surgery. The con- macular degeneration or any signs of discontinuity clusions, however, are varied. Amemiya et al2 in photoreceptor inner and outer segment junction To cite: Zhou C, Lin Q, conducted a study among 299 patients with RRD, (IS/OS) or external limiting membrane (ELM) in Chen F. Br J Ophthalmol and all of them underwent scleral buckling and 93 the initial OCT test); and (3) the follow-up period 2017;101:725–729. (31.10%) patients experienced persistent <6 months. We contacted all patients who met the Zhou C, et al. Br J Ophthalmol 2017;101:725–729. doi:10.1136/bjophthalmol-2016-309097 725 Downloaded from http://bjo.bmj.com/ on August 21, 2017 - Published by group.bmj.com Clinical science inclusion criteria and explained the purpose of the study, and each eye using analysis software V.5.1.3. In selected cases, verti- they participated in this study voluntarily without any additional cal or oblique scans were obtained to better evaluate the compensation. Of the 588 patients who met the inclusion cri- observed abnormalities. Two doctors (CZ, QL) assessed the teria, 88 patients were not reached, and 71 declined to partici- integrity of IS/OS and ELM. Diagnosis of a disrupted line was pate in this study for other reasons, such as geographic or time made based on loss and irregularity of the hyper-reflective line limitations. Of the 429 subjects who agreed to return for the of the IS/OS or ELM junction. The consistency between the follow-up visit, 26 patients were excluded for the re-detachment results from the two graders was 98.42%. A third grader, who of the retina, and 46 patients were excluded from the analysis was not involved in the above assessment, was asked to deliber- because of incomplete data collection (eg, the unsatisfied quality ate discrepancies. All of the graders were masked to the clinical of OCT caused by media opacity), leaving a final sample of 380 outcomes of the patients. Abnormal macula structures, for eyes of 357 patients. example, ERM, subretinal fluid (SRF), macula hole and CMO, were also documented. Data collection Informed consent was obtained from all patients at the Statistical analysis follow-up visit. This study adhered to the tenets of the BCVA was converted to the logarithm of the minimum angle of Declaration of Helsinki and was approved by the Shanghai resolution (logMAR). Counting fingers, hand motion and light Jiaotong University research ethics committee. perception were assigned the logMAR units of 2.1, 2.4 and 2.7, Age, gender, refractive status, number of quadrants involved respectively. The data were analysed using SAS software (V.9.2, in retinal detachment (RD), grade of PVR, preoperative and SAS Institute, Cary, North Carolina, USA) and were reported as postoperative best-corrected visual acuity (BCVA), surgical the mean±SD or n (%). Univariate analyses, either Student’s 2 approaches, baseline macula status tested by OCT, refractive t-test (continuous factors) or a χ test (categorical factors), were error and tamponade types were collected by chart review. At used to identify the possible correlates of metamorphopsia. the follow-up, the retinas of all patients were examined by the When evaluating the impact of different surgical approaches on same surgeon (FC) with slit-lamp biomicroscopy through metamorphopsia, 32 eyes were excluded because they received dilated pupil. BCVA was tested using the Snellen visual acuity multiple types of surgery. Then, the significant factors were chart. In addition, each patient was questioned about the pres- entered into a stepwise logistic regression model as independent ence of metamorphopsia with an Amsler grid. If present, the variables to explore the independent predictors for metamor- patients were asked to show the examiner the location of phopsia. All tests were two sided, and a p value <0.05 was con- the distorted lines on the grid. No quantitative assessment of sidered statistically significant. the metamorphopsia was performed. Images were acquired with Spectralis OCT (Heidelberg RESULTS Engineering, Heidelberg, Germany) at the same follow-up visit. A total of 380 eyes of 357 patients were included in this study, We performed five horizontal and five vertical raster scans for among whom 222 patients (62.18%) were male and 135 Table 1 Demographic and baseline clinical characteristics Total Metamorphopsia (+) Metamorphopsia (−) p Value Gender 0.71 Male 241 114 127 Female 139 63 76 Age 46.4 43.9 48.5 <0. 01* Duration of symptoms (days) 52.1 73.8 33.3 0.02* Number of quadrants involved 2.1 2.3 1.9 <0. 01* Proliferative vitreoretinopathy 0.03* A 35 13 22 B 309 140 169 C 36 24 12 Macular status <0. 01* On 126 33 93 Off 254 144 110 Preoperative spheroequivalent refraction (dioptre) −4.8 −4.9 −4.6 0.53 Baseline logarithm of the minimum angle of resolution best-corrected visual acuity 1.4 1.6 1.3 <0.