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AIM: To analyze the application value of spectral domain-optical coherence tomography(SD-OCT)parameters on evaluating visual acuity improvement after internal limiting membrane peeling of macular hole.METHODS: The retrospective analysis was performed on the clinical data of 82 patients(82 eyes)with idiopathic macular hole(IMH)who underwent vitrectomy + internal limiting membrane peeling + long-acting gas tamponade in the hospital between May 2019 and February 2021. The correlation between IMH closure and SD-OCT parameters at 3mo after surgery was analyzed, and the risk factors for poor postoperative visual acuity improvement were evaluated.RESULTS: Spearman rank correlation coefficient analysis showed that IMH closure at 3mo after operation was positively correlated with preoperative external limiting membrane(ELM)defect diameter(rs=0.308, P<0.05), and it was negatively correlated with preoperative macular hole index(MHI; rs=-0.266, P<0.05). Logistic regression analysis revealed that preoperative MHI≥0.5 was a protective factor affecting poor postoperative visual acuity improvement(OR=0.691, P<0.05).CONCLUSION: SD-OCT can predict the surgical efficacy by detecting the preoperative MHI and ELM defect diameter, and it is beneficial to judging the improvement of visual function.
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Purpose: To evaluate the absence of external limiting membrane (ELM) and ellipsoid zone (indistinct retinal outer layers, I?ROL) in the walls of idiopathic full?thickness macular holes (FTMHs) circumferentially on optical coherence tomography (OCT) and its correlation with surgical outcome. Methods: In this retrospective observational study, OCT images of patients undergoing vitrectomy for FTMHs with at least 3?months of postoperative follow?up were analyzed for preoperative circumferential extent of I?ROL. Derived macular hole indices such as hole form factor (HFF), macular hole index (MHI), tractional hole index (THI), and hole diameter ratio (HDR) were also calculated. The circumferential extent of I?ROL was correlated with derived hole indices as well as anatomical closure, foveal architecture, and restoration of ELM following surgery. Results: All nine eyes (eight patients) with FTMH (mean size: 610.11 ± 122.95 microns) in the study showed I?ROL in ?1 quadrant. The mean HFF, MHI, THI, and HDR values were 0.72 ± 0.09, 0.35 ± 0.05, 0.71 ± 0.24, and 0.53 ± 0.14, respectively. All eyes achieved type?1 hole closure with improvement in best?corrected visual acuity to 0.58 ± 0.32 LogMAR from 0.81 ± 0.26 LogMAR. Regular foveal architecture was achieved in six eyes. Out of these, five eyes had I?ROL in ?2 quadrants, and one eye had I?ROL in <2 quadrants (P = 0.0476). Restoration of ELM was seen in aforementioned six eyes (complete = 5, partial = 1). Out of the five eyes with complete ELM restoration, four had a circumferential extent of I?ROL in ?2 quadrants (P = 0.0476). Complete restoration of ELM was associated with the complete restoration of the ellipsoid zone in three eyes. Conclusion: Preoperative circumferential extent of I?ROL in FTMH walls can be a potential predictive OCT marker for the type of closure, postoperative foveal architecture, and ELM restoration.
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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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@#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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Purpose: To correlate the structural and functional changes following intravitreal injection of dexamethasone 0.7 mg (Ozurdex®) implant in patients with recalcitrant uveitic cystoid macular edema (CME). Materials and Methods: In a prospective, interventional, nonrandomized study, 30 eyes (27 patients) with uveitic CME received Ozurdex® implant and were followed‑up for 24 weeks at periodic intervals to monitor structural alterations seen on spectral domain optical coherence tomography (SD-OCT). The outcome measures included change in central macular thickness (CMT) and best‑corrected visual acuity (BCVA) as well as structural alterations seen on OCT such as change in the height of cystoid spaces (CSs) and sub‑foveal serous retinal detachment (SSRD). The integrity of external limiting membrane and inner‑outer segment junction was assessed at baseline and follow‑up visits. Results: Mean age of the patients was 46.09 ± 15.66 years. The mean CMT decreased by 96 μm at 1‑day, 231.64 μm at 1‑week, 254.21 μm at 4 weeks and 249.14 μm at 12 weeks (P < 0.001) compared with baseline. BCVA improved from a baseline mean of 0.62 LogMAR units to 0.49 on day 1 to 0.31 at 24 weeks (P < 0.001). A decrease in the mean height of CS, that is, 133.28 μm from a baseline of 317.71 μm was noted on the 1st day (P < 0.001). 4 eyes demonstrated the presence of CS at 4 weeks, 1 eye at 6 weeks and 3 eyes at 12 weeks. At baseline, 16 eyes (53.33%) demonstrated the presence of SSRD. Among these, 11 eyes showed resolution of SSRD on day 1. SSRD resolved in all patients at 4 weeks and was maintained up to 24 weeks. Conclusions: Ozurdex® implant improves the visual outcome of patients with recalcitrant uveitic CME. Reversibility of retinal changes may be possible following treatment with dexamethasone implant. Thus final visual outcome may be independent of pretreatment CMT, the height of CS or SSRD.
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Purpose: The aim was to evaluate outcomes and predictors for anatomical success in macular hole (MH) surgery. Materials and Methods: This was a prospective cohort study of patients operated for idiopathic MH with stages II, III or IV. Patients underwent pars plana vitrectomy with internal limiting membrane (ILM) peeling, internal gas tamponade, and postoperative face down positioning. The primary outcome measure was anatomical closure of MH, while secondary outcome measure was postoperative external limiting membrane (ELM) continuity. Effect of MH size, duration of MH, size of ILM peel, type of gas tamponade (SF6 vs. C3F8) and macular hole index (MHI) on anatomical MH closure was also evaluated. Results: Of the 62 eyes operated, anatomical closure of MH was achieved in 55 eyes (88.7%). The median duration of follow‑up was 8 months (range: 6–15 months). Mean BVCA improved from 0.94 ± 0.26 at baseline to 0.40 ± 0.23 logMAR at last follow‑up (P = 0.01). There was a statistically significant association between size of ILM peel and anatomical closure of MH (P = 0.04). Duration of symptoms, size of MH, type of gas tamponade, MHI had no effect on anatomical closure (P = 0.22, 0.28, 0.40 respectively, Chi‑square test). Postoperative continuity of the ELM was significantly associated with a shorter symptom duration (<6 months) before surgery. Conclusion: Acceptable anatomical closure could be attained with the defined technique. Size of ILM peel is a new predictor of anatomical success while symptom duration affects postoperative ELM continuity.