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Objective?Diabetic retinopathy (DR), a microvascular complication of diabetes, is a leading cause of preventable blindness. Spectral domain optical coherence tomography (SD-OCT) provides cross-sectional and topographical imaging of the retina. SD-OCT resolves outer retinal layers into three hyperreflective bands—external limiting membrane (ELM), ellipsoid zone (EZ), and retinal pigment epithelium (RPE). In this article, we have studied the role of these outer retinal layers in structural and molecular changes taking place in DR. Materials and Methods?Articles with clinical features, pathogenesis, diagnosis, and treatment of DR were thoroughly studied. Articles were searched on PubMed, MEDLINE, and Cochrane Library from 2000 to 2020. Studies focusing on the role of ELM, EZ, and RPE in pathogenesis of DR based on SD-OCT were included. Results?The long-standing hyperglycemia leads to protein glycosylation resulting in formation of advanced glycation end products (AGEs). AGEs have an impact through their effect on retinal microvasculature, vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1, nitrosative and oxidative stress, and vitamin D and calcium metabolism. All these factors have been linked with disruption of outer retinal layers. AGEs lead to vascular endothelial dysfunction and release of proangiogenic factors by increasing the expression of VEGF in retinal pericytes and RPE cells. This leads to leakage and fluid accumulation resulting in diabetic macular edema (DME). In DME, there is sequential disruption of ELM and EZ and decrease in visual acuity (VA). The RPE alterations have been reported to be associated with the severity of DR and decrease in VA. Anti-VEGF therapy, most common treatment of DME, leads to restoration of barrier effect of ELM, it was found to be restored first followed by EZ restoration. Newer anti-AGEs agents and their receptor blockers are being developed which have a positive effect on maintaining the health of RPE. Conclusion?A complex molecular association exists between the structural changes in ELM, EZ, and RPE in DR. SD-OCT is an indispensable tool to study these changes as integrity of these outer layers of retina is essential for maintaining visual function of retina in DR.
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Objective:To analyze the effect of vitrectomy combined with internal limiting membrane (ILM) peeling on the prevention of post-vitrectomy epiretinal membrane (ERM) in macular-off rhegmatogenous retinal detachment (RRD) and its influence on visual outcomes.Methods:A cohort study was conducted.Seventy-four patients (74 eyes) with macular-off RRD, who realized retinal reattachment after vitrectomy and silicone oil tamponade from January 2015 to January 2018 in Baoding NO.1 Central Hospital, were enrolled.The patients were divided into the non-ILM peeling group (36 cases, 36 eyes) and ILM peeling group (38 cases, 38 eyes) according to whether they received ILM peeling or not.The patients underwent silicone oil removal within 3 to 5 months after the surgery.Best corrected visual acuity (BCVA), slit-lamp microscopy, indirect ophthalmoscopy, fundus photography and optical coherence tomography (OCT) were examined before and at 1, 6 and 12 months after the surgery.This study protocol adhered to the Declaration of Helsinki and was approved by an Ethics Committee of Baoding NO.1 Central Hospital (No.[2019]042). Written informed consent was obtained from each patient.Results:There was no ERM found in the two groups at 1 month after the operation.There were 3 eyes (8.33%) with ERM in the non-ILM peeling group and 2 eyes (5.26%) in the ILM peeling group at 6 months after the operation, with no statistically significant difference between them ( P=0.067). There were 9 eyes (25.00%) with ERM in the non-ILM peeling group and 4 eyes (10.53%) in the ILM peeling group at 12 months postoperatively, with no statistically significant difference between them ( χ2=2.674, P=0.102). There was a significant difference in BCVA between before and after the operation in the two groups ( Ftime=31.692, P<0.001). Postoperative 1-, 6-and 12-month BCVA were all significantly better than the preoperative BCVA in the two groups (all at P<0.05). There was no significant difference in BCVA between the two groups ( Fgroup=0.117, P=0.773). OCT images showed that there were 25 eyes (77.78%) and 30 eyes (78.95%) with the intact ellipsoid zone in the non-ILM peeling group and ILM peeling group at 12 months after the operation, respectively, with no statistically significant difference between them ( χ2=0.875, P=0.350). Conclusions:Compared with vitrectomy alone, the vitrectomy combined with ILM peeling does not show better efficacy in the prevention of ERM occurrence in macula-off RRD patients and has no obvious influence on postoperative visual acuity.
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@#AIM: To identify factors associated with metamorphopsia in patients with rhegmatogenous retinal detachment(RRD)who underwent primary vitrectomy(PPV). <p>METHODS:This retrospective study included 94 patients(94 eyes)who underwent 23G PPV for repair of RRD between January, 2017 and January, 2019. Each patient were examined both eyes preoperatively and postoperatively(at 1, 6, 12mo and last visits). At each time-point, patients received a complete ophthalmological examination, including best corrected visual acuity(BCVA), intraocular pressure, slit-lamp biomicroscopy, optical coherence tomography(OCT), and M-chart examination.<p>RESULTS: One month after surgery, metamorphopsia occurred in 53%(<i>n</i>=50), the mean M value was 0.68±0.28. The metamorphopsia rate differed significantly between macula-off and macula-on RRD(<i>P</i><0.01). There was significant difference in M-chart among the different time(<i>F</i>=26.442, <i>P</i><0.01). Univariate analysis demonstrated that the macula status, location of retinal breaks, and disrupted EZ was a risk factor that was significantly associated with metamorphopsia. In multivariate analysis, macula-involving retinal detachment(<i>OR</i>=9.020, 95% <i>CI</i>:1.808-45.011, <i>P</i>=0.007)and disrupted EZ(<i>OR</i>=10.570, 95% <i>CI</i>:2.909-38.400, <i>P</i><0.01)was a significant predictors of metamorphopsia.<p>CONCLUSION: The metamorphopsia was improved after anatomically successful RRD surgery. Macular involvement retinal detachment and disrupted EZ were more likely to develop metamorphopsia.
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@#AIM: To observe the effect of pars plana vitrectomy(PPV)internal limiting membrane(ILM)insertion and nerve growth factor(NGF)injection in the treatment of large idiopathic macular hole(IMH). <p>METHODS: This was a retrospective clinical study which included 16 patients(16 eyes)with large IMH diagnosed in the Affiliated Eye Hospital of Nanjing Medical University from May 2018 to May 2020. All patients were treated with PPV combined with ILM insertion and NGF injection and the follow-up period was at least 6mo. Macular hole closure rates, best-corrected visual acuity(BCVA)(LogMAR), and optical coherence tomography(OCT)findings including ellipsoid zone(EZ)and external limiting membrane(ELM)were analyzed, the complications were also observed postoperatively.<p>RESULTS: The BCVA was 1.15±0.21 before operation, and the follow-up of BCVA was 1.02±0.19 and 0.87±0.24 respectively at 3 and 6mo after operation(<i>F</i>=34.966, <i>P</i><0.01); The BCVA was improved 3 and 6mo after operation(<i>P</i><0.01), and the BCVA at 6mo after operation was better than that at 3mo(<i>P</i><0.01). The closure rate of the MH was 100% and 11 eyes showed U-shaped closure in OCT(69%), 3 eyes were V-shaped closure(19%)and 2 eyes were irregular closure(13%). The BCVA of U-shaped closure group, V-shaped closure group and irregular closure group were 0.75±0.18, 1.1±0.19, and 1.20±0.00 respectively(<i>F</i>=6.937, <i>P</i><0.01). The recovery of BCVA in U-shaped closure group was significantly better than that in V-shaped closure group and irregular closure group(<i>P</i>=0.027, 0.007). Six months after operation, 10 eyes(91%)of ELM and 7 eyes(64%)of ellipsoid zone resumed continuity in U-shaped closure group, 2 eyes(67%)of ELM and 1 eye(33%)of resumed continuity in V-shaped closure group. ELM and ellipsoidal zone were not recovered continuously in irregular closure group(<i>P</i><0.05). During the follow-up period, we found no ocular or systemic complications.<p>CONCLUSION: PPV combined with ILM insertion and NGF injection is safe and effective in treating large IMH. The synergetic effect of NGF and ILM can obviously promote the closure of IMH, which is beneficial to the recovery of photoreceptor layer integrity and the improvement of visual function after operation.
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@#AIM: To investigate the changes in spectral domain optical coherence tomography(SD-OCT)quantitative and qualitative parameters in a group of patients with age-related macular degeneration(AMD)that underwent bevacizumab intravitreal injections(IV). We assessed if one or more of these parameters can be used as prognostic factors of the post treatment visual acuity(VA).<p>METHODS:Totally 66 eyes of 61 patients, with treatment naive AMD, that were treated with at least 3 monthly bevacizumab IV, were retrospectively studied. SD-OCT quantitative \〖central foveal thickness(CFT), external limiting membrane(ELM)and ellipsoid zone(EZ)lengths\〗 and qualitative parameters were studied and compared before and after IV. We also tried to establish correlation between these parameters and before/after treatment VA.<p>RESULTS:Mean VA(logMAR), CFT(μm), ELM length(μm)and EZ length(μm)changed from pre-IV values of 0.62±0.41, 419.3±110.0, 378.2±377.2 and 156.4±253.7 to post-IV values of 0.53±0.44, 325.8±117.9, 547.1±421.5 and 173.1±207.1. There was correlation between pre-IV VA and pre-IV CFT(<i>rs</i>=0.27), ELM length(<i>rs</i>=-0.30)and ELM disruption(<i>rs</i>=0.43). There was also correlation between post-IV VA and post-IV ELM length(<i>rs</i>=-0.40). Post-IV VA showed correlation with pre-IV VA(<i>rs</i>=0.66), ELM length(<i>rs</i>=-0.35)and ELM disruption(<i>rs</i>=0.46). <p>CONCLUSION: In our study group pre-IV VA, ELM length and ELM disruption can be used as post-IV VA prognostic factors.
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Background The patients who have undergone successful surgery for retinal detachment (RD) cannot recover their vision quickly,and the reason is not very clearly now.Objective This study was to compare the ellipsoid zone integrity in macula and frequency and duration of subretinal fluid after scleral buckling and pars plana vitrectomy (PPV) in primary macula-off rhegmatogenous RD,and to discuss the sequent influence of subretinal fluid on postoperative visual acuity.Methods A retrospective analysis was carried out on 66 cases of rhegmatogenous RD in Peking University People's Hospital from January 2010 to January 2013.All the cases were divided into 2 groups:scleral buckling group and PPV group.The courses of disease,refractive status,best corrected visual acuity (BCVA) and complications were recorded.The duration of subretinal fluid and ellipsoid zone integrity in macula were observed and the occurrence rates of subretinal fluid were calculated 1 month after surgery.Results There were no statistic differences on age,gender,courses of disease,refractive status and LogMAR visual acuity (all at P＞0.05).The average duration of subretinal fluid was (96 ±60) days in scleral buckling group,and (21 ±6) days in PPV group,with a statistically significant difference between the two groups (t =7.966,P =0.000).The occurrence rate of subretinal fluid at 1 month after surgery was 78.6％ in the scleral buckling group and 12.5％ in the PPV group,with a statistically significant difference between the two groups (x2=26.891,P =0.000).The LogMAR visual acuity was significantly different between the patients with and without subretinal fluid at 1 month after scleral buckling surgery (t=3.185,P=0.003).The LogMAR visual acuity was not significantly different between the scleral buckling group and PPV group 6 months after scleral surgery (t =1.876,P =0.065).The LogMAR visual acuity was not significantly different between the patients with and without subretinal fluid at 6 month after scleral buckling surgery (t =1.755,P=0.087).After the subretinal fluid was reabsorbed,the LogMARs visual acuity were significantly different between the patients with intact ellipsoid zone and with disrupt ellipsoid zone in both groups (scleral buckling group:t=2.555,P=0.015;PPV group:t=4.005,P=0.001).Conclusions The disruption extent of the ellipsoid zone is related to the duration of RD,and the integrity affects the postoperative visual acuity distinctly.The subretinal fluid is removed more rapidly after PPV when compared with scleral buckling in macula-off rhegmatogenous RD.The subretinal fluid delays visual recovery postoperatively but the operation method does not influence final visual acuity seriously.