[Biomechanics of diabetic vitreopapillary traction syndrome]. / Biomekhanika diabeticheskogo vitreopapillyarnogo traktsionnogo sindroma.

Diabetic vitreopapillary traction syndrome (VPT) is a variant of diabetic retinopathy (DR) that can lead to vision loss in advanced stages. This review reports on the biomechanics of the vitreous in the pathogenesis of proliferative DR, in particular diabetic VPT. The article analyzes and summarizes literature data, presents the views of different authors on this problem, and provides the results of Russian and foreign scientific research on this pathology. It is concluded that further research in this area can lead to a significant improvement in the results of therapy, timely diagnosis, and preservation of vision in patients with DR.

Indications and outcomes for intravitreal injection of C3F8 gas for symptomatic vitreomacular traction.

To evaluate the indications and outcomes of perfluoropropane (C3F8) gas injection for symptomatic vitreomacular traction (VMT). A retrospective analysis of eyes with VMT treated with 0.3 mL of C3F8 gas was performed. Patients were not asked to posture after gas injection. In phakic patients, cataract surgery was performed simultaneously. Patients were examined after one week and one month postoperatively. Twenty-nine consecutive eyes of 26 patients with symptomatic VMT who underwent pneumatic vitreolysis were included. A complete posterior vitreous detachment was achieved in 18 eyes (62.1%) after a single gas injection at the final visit. The rate of posterior vitreous detachment was reduced significantly with the presence of epiretinal membrane (ERM) (p = 0.003). Three eyes formed a macular hole (MH) postoperatively and another eye developed a retinal detachment. Mean visual acuity increased significantly after one month (p < 0.008). Pneumatic vitreolysis is a viable option for treating VMT with few adverse events. Patient with concomitant ERM had a significantly lower success rate.

Primary vitreoretinal lymphoma: a diagnostic and management challenge.

Primary vitreoretinal lymphoma (PVRL) is a rare form of primary central nervous system (CNS) lymphoma (PCNSL) arising in the intraocular compartment without brain involvement. Despite its apparent indolent clinical course, PVRL can cause permanent vision loss and CNS relapse, the major cause of death in patients with PVRL. The pathophysiology of PVRL is unknown. As in PCNSL, the transformation of the tumor cells likely originates outside the CNS, before the cells migrate to the eye and proliferate within an immune-permissive microenvironment. PVRL exhibits a biased immunoglobulin repertoire, suggesting underlying antigen selection. The diagnosis remains challenging, requiring close coordination between ophthalmologists and cytologists. Because of their rarity and fragility in the vitreous, lymphoma cells cannot always be identified. Interleukin levels, molecular biology, and imaging are used in combination with clinical ophthalmological examination to support the diagnosis of PVRL. Multi-institutional prospective studies are urgently needed to validate the equivocal conclusions regarding treatments drawn from heterogeneous retrospective or small cohort studies. Intravitreal injection of methotrexate or rituximab or local radiotherapy is effective at clearing tumor cells within the eyes but does not prevent CNS relapse. Systemic treatment based on high-dose methotrexate chemotherapy, with or without local treatment, might reduce this risk. At relapse, intensive consolidation chemotherapy followed by stem cell transplantation can be considered. Single-agent ibrutinib, lenalidomide, and temozolomide treatments are effective in patients with relapsed PVRL and should be tested as first-line treatments. Therapeutic response assessment based on clinical examination is improved by measuring cytokine levels but still needs to be refined.

SURGICAL OUTCOMES OF VITREOMACULAR TRACTION TREATED WITH FOVEAL-SPARING PEELING OF THE INTERNAL LIMITING MEMBRANE.

PURPOSE: To compare sensitivity of the retina after complete internal limiting membrane (ILM) peeling versus foveal-sparing ILM peeling in vitrectomy for vitreomacular traction syndrome. METHODS: This was a randomized, prospective, comparative study. Thirty-four eyes were randomized to undergo peeling with foveal sparing of the ILM (FS group) or complete peeling group. Foveal and perifoveal retinal sensitivity, visual acuity, and central macular thickness were the main outcome measures. RESULTS: Parafoveal retinal sensitivity exhibited a significant improvement in both the FS and complete peeling groups (+2.43 ± 0.82 dB and +1.79 ± 0.86 dB, respectively; P = 0.037). Significant improvements were observed in both visual acuity and central macular thickness in both groups. No cases of epiretinal membrane recurrence were observed in the FS group. CONCLUSION: Both the FS and complete peeling surgical techniques are safe and yielded good anatomical and functional results; however, a significant difference in favor of FS was found in relation to the best-corrected visual acuity and perifoveal retinal sensitivity. Preservation of the foveal ILM disc allowed the anatomical restoration of the foveal architecture in most vitreomacular traction syndrome cases without signs of stiffening or ILM fibrosis over a follow-up period of 1 year.

Can Vitreous Reflux Affect The Short-Term Treatment Response After Intravitreal Ranibizumab Injection?

PURPOSE: The aim of this study was to evaluate the effect of vitreous reflux (VR) on the short-term effect of intravitreal ranibizumab injection. MATERIALS AND METHODS: The study included 181 eyes of 81 age-related macular degeneration (AMD) and 100 diabetic macular edema (DME) patients. Treatment response was evaluated by measuring central macular thickness (CMT) as well as 1 mm and 3 mm central macular thicknesses (MT1 and MT3). Patients were grouped as; Group 1: no VR, Group 2: <3 mm VR, and Group 3: >3 mm VR according to conjunctival bleb diameters. The data were analyzed using variance, correlation and regression analyses. RESULTS: In AMD patients, reduction of CMT values following the treatment were 88.3 ± 110.6 µm in Group 1, 85.6 ± 158.7 µm in Group 2, and 93.1 ± 92.2 µm in Group 3. Likewise, in DME patients, it was 82.4 ± 88.4 µm, 72.9 ± 109.9 µm, and 73.7 ± 113.7 µm, respectively. Reduction of MT1 values after the treatment were 47.4 ± 72.6 µm, 36.0 ± 131.9 µm, and 36.7 ± 114.4 µm in AMD patients, and 33.3 ± 72.5 µm, 36.6 ± 90.2 µm, and 46.9 ± 83.4 µm in DME patients. In all comparisons among groups of VR, macular thickness (MT) change did not exhibit significant difference following an intravitreal ranibizumab treatment (p > .05). CONCLUSION: We found that the increase in VR amount did not adversely affect the decrease in MT after intravitreal ranibizumab treatment in AMD and DME patients.

FLOW DYNAMICS OF BEVELED-TIP AND FLAT-TIP VITREOUS CUTTERS.

PURPOSE: To compare the flow dynamics of beveled-tip to that of flat-tip vitreous cutters. METHOD: The aspiration rates of balanced salt solution and swine vitreous were measured for 25-gauge and 27-gauge beveled-tip and flat-tip vitreous cutters. Fluorescent polymer microspheres were mixed with balanced salt solution to make the flow visible. The flow dynamics at maximal cutting rates and reflux of balanced salt solution were measured with video images of a high-speed camera. RESULTS: The aspiration rates of balanced salt solution of the 25-gauge and 27-gauge beveled-tip cutters were significantly higher than that of the flat-tip cutters at 7,500 cut/min (P = 0.0001, P = 0.038, respectively). The aspiration rate of swine vitreous by the 25-gauge beveled-tip cutter was significantly higher than that of the flat-tip cutters (P = 0.006). The mean aspiration flow in front of the cutter was significantly faster for both beveled-tip than flat-tip cutters (P = 0.003, P = 0.023). The angle of the mean aspiration flow of both beveled-tip cutters was turned to the proximal side (P = 0.004, P = 0.003). The mean reflux flow of both beveled-tip cutters was significantly faster than that of the flat-tip cutters (P = 0.006, P = 0.006). CONCLUSION: The beveled-tip cutters have a greater velocity of aspirating frontal and proximal flow resulting in higher aspiration rates and greater reflux flow velocity.

Continued smoking and posterior vitreous adhesion in the elderly evaluated on swept-source optical coherence tomography.

In this cross-sectional study including 1150 eyes of 681 volunteers ≧ 65 years old without retinal pathology, factors affecting the progression of posterior vitreous detachment (PVD) were investigated. PVD stages were diagnosed based on swept-source optical coherence tomography (SS-OCT). Linear mixed effect model was used to determine whether age, gender, diabetes mellitus (DM), hypertension (HT), dyslipidemia (DL), and smoking status were associated with various stages of PVD. As a result, the multivariable analysis disclosed that the associations between older age and higher PVD stages (estimate [95% CI], 0.031 [0.020 to 0.042]; P < 0.0001), and current smokers and lower PVD stages (estimate [95% CI], - 0.24 [- 0.43 to - 0.056]; P = 0.011) were statistically significant. In contrast, female gender was not an independent factor affecting PVD stages in the elderly. Our analysis indicated that higher PVD stages observed in female eyes may be due to confounding effect, in which current smokers were predominantly males (i.e., 12.6% among males vs. 3.9% among females, P < 0.0001). In conclusion, our findings suggest that continuous smoking is associated with an adherent vitreoretinal interface in the elderly.

Quantitative analysis with volume rendering of pathological myopic eyes by high-resolution three-dimensional magnetic resonance imaging.

Discovering a relationship between axial length and vitreous volume would be helpful since the axial length is easier to measure than magnetic resonance imaging (MRI) parameters. This study aimed to analyze the topography of human eyes with pathological myopia through volume rendering images by high-resolution 3D-MRI and to establish a model to estimate the vitreous volume.This was a retrospective, non-randomized, controlled study of patients evaluated at Tongren Hospital from July 7, 2007 to December 12, 2018. The controls were emmetropic volunteers. All participants underwent ophthalmic examinations. Axial length was measured with an IOL Master. High-resolution 3D MRI and volume rendering was utilized for all the eyes. Logistic regression was used to establish a model to predict the vitreous volume.A total of 280 emmetropic eyes and 290 eyes with pathological myopia were included. Males represented 60.7% and 65.5% of the individuals. The mean axial lengths of those two groups were 23.1 ±â€Š0.8 mm (95%CI: 22.7-23.4 mm) and 28.3 ±â€Š2.2 mm (95%CI: 27.5-29.2 mm), respectively (P < .001). The regression model in the pathological myopic group for calculating the vitreous volume according to the axial length was: Vitreous volume = 546.27 × axial length - 6977.12. The regression model in the emmetropic group for calculating the vitreous volume according to the axial length was: Vitreous volume = 458.35 × axial length - 6331.14 (R = 0.360, P = .001).Elongation of the axial length is involved in eyeball enlargement in pathological myopic eyes. Measurement of the axial length could be recommended for the estimation of the vitreous volume during vitrectomy if vitreous cavity filling is needed.

A mechanical model of posterior vitreous detachment and generation of vitreoretinal tractions.

We propose a mechanical model of generation of vitreoretinal tractions in the presence of posterior vitreous detachment (PVD). PVD is a common occurrence with aging, and it consists in the separation of the vitreous body from the retina at the back pole of the eye, due to progressive shrinking of the vitreous gel. During this separation process, vitreoretinal tractions are generated at regions of high adhesion between the vitreous and the retina. Such tractions are mainly responsible for the creation of retinal tears, which can lead to retinal detachment. We describe the PVD evolution developing a continuum model of a shrinking soft body, representing the vitreous humor gel phase. In the model, the vitreous is surrounded by a membrane, stiffer than the bulk, the vitreous cortex, and it is contained within a rigid spherical domain, the vitreous chamber. The membrane is attached to the spherical wall and the adhesion strength is spatially non-uniform, increasing from the back to the front of the chamber, according to clinical observations. During the shrinking process, the vitreous undergoes elastic distortions, owing to the spatially variable adhesion on the wall, and this produces boundary tractions. We also consider the clinically relevant case of anomalous PVD, in which regions of focal adhesion between the vitreous and the retina exist, leading to the generation of strong, localized tractions. The model reproduces a PVD evolution in good qualitative agreement with clinical observations and makes it possible to correlate the shape of the detached vitreous with the intensity of vitreoretinal tractions.

Back to the Future: Vitreous Pupillary Block and Glaucoma in a Child After Lensectomy.

The authors present a case of poorly controlled glaucoma following lensectomy. An examination under anesthesia revealed iris bombe of the anterior vitreous face. This case helps emphasize the importance of a generous anterior vitrectomy at the time of lensectomy in the pediatric population to avoid secondary glaucoma. [J Pediatr Ophthalmol Strabismus. 2020;57:e48-e50.].

Assessment of Vitreous Structure and Visual Function after Neodymium:Yttrium-Aluminum-Garnet Laser Vitreolysis.

PURPOSE: Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser treatment is performed on vitreous floaters, but studies of structural and functional effects with objective outcome measures are lacking. This study evaluated Nd:YAG laser effects by comparing participants with vitreous floaters who previously underwent laser treatment with untreated control participants and healthy persons without vitreous floaters using quantitative ultrasonography to evaluate vitreous structure and by measuring visual acuity and contrast sensitivity function to assess vision. DESIGN: Retrospective, comparative study. PARTICIPANTS: One eye was enrolled for each of 132 participants: 35 control participants without vitreous floaters, 59 participants with untreated vitreous floaters, and 38 participants with vitreous floaters previously Nd:YAG-treated. Of these, 25 were dissatisfied and sought vitrectomy; 13 were satisfied with observation. METHODS: The 39-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-39) to assess participant visual well-being, quantitative ultrasonography (QUS) to measure vitreous echodensity, and best-corrected visual acuity (BCVA) and contrast sensitivity function (CSF) to evaluate vision. MAIN OUTCOME MEASURES: Results of NEI-VFQ-39, QUS, BCVA, and CSF. RESULTS: Compared with control participants without vitreous floaters, participants with untreated vitreous floaters showed worse NEI-VFQ-39 results, 57% greater vitreous echodensity, and significant (130%) CSF degradation (P < 0.001 for each). Compared with untreated eyes with vitreous floaters, Nd:YAG-treated eyes had 23% less vitreous echodensity (P < 0.001), but no differences in NEI-VFQ-39 (P = 0.51), BCVA (P = 0.42), and CSF (P = 0.17) results. Of 38 participants with vitreous floaters who previously were treated with Nd:YAG, 25 were dissatisfied and seeking vitrectomy, whereas 13 were satisfied with observation. Participants seeking vitrectomy showed 24% greater vitreous echodensity (P = 0.018) and 52% worse CSF (P = 0.006). Multivariate linear regression models confirmed these findings. CONCLUSIONS: As a group, participants previously treated with Nd:YAG laser for bothersome vitreous floaters showed less dense vitreous, but similar visual function as untreated control participants with vitreous floaters. Because some treated eyes showed less dense vitreous and better visual function than those of untreated control participants, a prospective randomized study of Nd:YAG laser treatment of vitreous is warranted, using uniform laser treatment parameters and objective quantitative outcome measures.

Serum and vitreous resistin levels in patients with proliferative diabetic retinopathy.

AIM: The aim of the study was to investigate the serum and vitreous levels of resistin in patients with the proliferative diabetic retinopathy (PDR) and to compare those with age-matched control subjects. METHODS: The study included 45 eyes with PDR (group 1) and a control group of 22 (group 2). All eyes underwent vitrectomy surgery. The lipid profile, fasting blood glucose (FBG), HbA1c and resistin levels were investigated in blood samples of all subjects. Complete ophthalmological examinations were evaluated. Vitreous samples were collected from both groups during vitrectomy surgery and resistin levels were investigated in those samples. The results were evaluated using SPSS 9.0 software. RESULTS: The demographic characteristics of the diabetic group and the control group were similar (p > 0.05). There was no significant difference between the groups in respect of mean visual acuity (VA), body mass index (BMI) values, or lipid profiles (p ˃ 0.05). There was no measurable value of resistin in the vitreous samples of all the eyes. The mean blood resistin level was 367 ng/ml in the control group and 387 ng/ml in the study group and the difference was not statistically significant (p > 0.05). CONCLUSIONS: In the light of the findings of this study, it can be assumed that resistin did not pass through the vitreous at measurable levels. However, the serum resistin levels of the diabetic patients were higher than those of the control group although not statistically significant. Therefore, it can be considered that resistin does not play a major role in retinal neovascularization.

Retinal Pathologic Features on OCT among Eyes of Older Adults Judged Healthy by Color Fundus Photography.

PURPOSE: OCT has revealed many details of retinal disease that were not available with older imaging technologies. In eyes of adults older than 60 years with healthy maculas as determined by color fundus photography (CFP) and a validated grading system, we screened for pathologic features using OCT. We also tested visual function to assess potential impact of the observed pathologic features on patients. DESIGN: Cross-sectional study. PARTICIPANTS: Persons recruited from primary ophthalmology care clinics. METHODS: Color fundus photographs were assessed by the 9-step Age-Related Eye Disease Study scale. OCT macular volumes of participants at step 1 on the Age-Related Eye Disease Study scale, considered healthy, were reviewed by a retina specialist masked to other participant characteristics. Participants were tested for 6 different cone- and rod-mediated visual functions. MAIN OUTCOME MEASURES: Percentage of participants with disorders detected on OCT review and visual function measures. RESULTS: In 138 of 984 eyes (14%) considered healthy by CFP, pathologic features were detectable by OCT, with 8.4% having vitreomacular interface disorders. Among the low-prevalence disorders found, 5 eyes (0.5%) showed macular telangiectasia type 2. Relative to eyes lacking detectable chorioretinal pathologic features, eyes with any pathologic features were associated with poorer low-luminance visual acuity and rod-mediated dark adaptation. In eyes with epiretinal membranes, the largest single entity identified (n = 61 [6.2%]), significantly worse visual functions were best-corrected visual acuity (P = 0.0444), low-luminance visual acuity (P = 0.0151), and light sensitivity (central 3° and 9°; P = 0.0035 and P = 0.0097, respectively). CONCLUSIONS: Macular pathologic features with functional visual implications not identified by clinical examination or CFP are detectable with OCT. Vitreomacular interface disorders often are visually significant and treatable conditions that are visible on OCT, but are easily missed on CFP and clinical examination. Another such condition best seen on OCT is macular telangiectasia type 2, an untreatable disorder for which a clinical trial is in progress. OCT has a potential role in primary eye care clinics to screen for retinal pathologic features, especially in eyes with decreased visual acuity and otherwise normal examination results.

Persistent troublesome floaters necessitating the explantation of XtraFocus Pinhole IOL (Morcher).

A 41-year-old patient presented with blurred vision and photophobia in the left eye with an uncorrected visual acuity of 20/150, improving to 20/30 with pinhole and diagnostic rigid gas permeable lens trial. He had a history of trauma with subsequent cataract extraction with residual irregular astigmatism and traumatic mydriasis. XtraFocus Pinhole intraocular lens (Morcher) was implanted in the left eye and the vision improved to 20/40. Postoperatively, the patient experienced significant floaters which persisted to the extent of necessitating explantation of implant.

Comparative Analysis of Three-Dimensional Heads-Up Vitrectomy and Traditional Microscopic Vitrectomy for Vitreoretinal Diseases.

Purpose: To investigate the visual outcomes and occurrences of perioperative complications after three-dimensional (3D) heads-up vitrectomy compared with traditional microscopic (TM) surgery for vitreoretinal diseases. Methods: A retrospective case series comparison of 3D and TM vitrectomy performed on 124 and 202 eyes with a minimum follow-up of 6 months, respectively, by the same surgeon. Changes in visual acuity, primary anatomical success, operation time, and perioperative complications were evaluated. Results: There were no significant differences in age, gender, axial length, ocular and surgical history, surgical indication, and visual acuity between the two groups at baseline. Both groups showed a significant improvement in visual acuity at the final visit (both P < .05) and experienced comparable anatomical recoveries regarding epiretinal membranes, vitreous hemorrhage, macular holes, retinal detachment, and pathological myopic foveoschisis. The mean overall operation time was not significantly longer in the 3D group (31.0 ± 17.6 min) than the TM (31.0 ± 15.9 min) group (P = .994). The incidence rates of postoperative complications during the follow-up were similar between the 3D (30.6%) and TM groups (30.2%) (P = .932). Conclusions: The 3D and TM vitrectomy surgeries yielded comparable visual and anatomical outcomes for treatment of vitreoretinal diseases without a significant difference in the rate of complications. The 3D heads-up vitrectomy may be considered the treatment of choice for patients with various vitreoretinal diseases.

New use of a pupillary expansion ring to avoid intraoperative positive vitreous pressure during triple procedures.

Positive vitreous pressure can complicate cataract surgery during a triple procedure by inadvertently extending the capsulorhexis. This occurs because the procedure is open sky and positive vitreous pressure cannot be countered by injecting ophthalmic viscosurgical devices. We describe a new use of a pupillary expansion ring (Malyugin) to achieve a stable open anterior chamber under open sky during triple procedures. The scrolls are tucked under cut margins of the host cornea to create the capsulorhexis, the cataractous nucleus is removed, and an intraocular lens (IOL) is implanted in the bag. This technique is especially useful in cases of hypermature cataract and nondilating pupils with positive vitreous pressure in patients having triple procedures. The technique provides a stable open anterior chamber, increasing to the safety of the procedure and the chance of achieving a continuous curvilinear capsulorhexis and IOL implantation in the capsular bag.

An Ex Vivo Tissue Culture Model for Fibrovascular Complications in Proliferative Diabetic Retinopathy.

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and one of the leading causes of blindness in working-age adults. No current animal models of diabetes and oxygen-induced retinopathy develop the full-range progressive changes manifested in human proliferative diabetic retinopathy (PDR). Therefore, understanding of the disease pathogenesis and pathophysiology has relied largely on the use of histological sections and vitreous samples in approaches that only provide steady-state information on the involved pathogenic factors. Increasing evidence indicates that dynamic cell-cell and cell-extracellular matrix (ECM) interactions in the context of three-dimensional (3D) microenvironments are essential for the mechanistic and functional studies towards the development of new treatment strategies. Therefore, we hypothesized that the pathological fibrovascular tissue surgically excised from eyes with PDR could be utilized to reliably unravel the cellular and molecular mechanisms of this devastating disease and to test the potential for novel clinical interventions. Towards this end, we developed a novel method for 3D ex vivo culture of surgically-excised patient-derived fibrovascular tissue (FT), which will serve as a relevant model of human PDR pathophysiology. The FTs are dissected into explants and embedded in fibrin matrix for ex vivo culture and 3D characterization. Whole-mount immunofluorescence of the native FTs and end-point cultures allows thorough investigation of tissue composition and multicellular processes, highlighting the importance of 3D tissue-level characterization for uncovering relevant features of PDR pathophysiology. This model will allow the simultaneous assessment of molecular mechanisms, cellular/tissue processes and treatment responses in the complex context of dynamic biochemical and physical interactions within the PDR tissue architecture and microenvironment. Since this model recapitulates PDR pathophysiology, it will also be amenable for testing or developing new treatments.

ASSESSMENT OF ANATOMICAL AND FUNCTIONAL OUTCOMES WITH OCRIPLASMIN TREATMENT IN PATIENTS WITH VITREOMACULAR TRACTION WITH OR WITHOUT MACULAR HOLES: Results of OVIID-1 Trial.

PURPOSE: To evaluate the anatomical and functional outcomes with ocriplasmin in patients with vitreomacular traction (VMT) with or without macular hole (MH). METHODS: In a Phase 4, multicenter, single-arm, open-label study, eligible patients (VMT with focal adhesion, without epiretinal membrane, and with MH ≤400 µm [if present]) received a single intravitreal injection of ocriplasmin. Nonsurgical resolution of VMT (Day 28 [primary endpoint]), best-corrected visual acuity, MH closure, vitrectomy rate, and safety were assessed through Day 180. RESULTS: Overall, 466 patients were included in the full analysis set, of whom 47.4% had VMT resolution by Day 28; resolution rates in patients with VMT without MH, VMT with MH ≤250 µm, and VMT with MH >250 to ≤400 µm were 43.4%, 68.6%, and 62.7%, respectively. Macular hole closure was higher in eyes with VMT and MH ≤250 µm (57.1%) than in eyes with VMT and MH >250 to ≤400 µm (27.5%) at Day 28. Overall, 30.8% of patients with VMT resolution gained ≥10 letters in best-corrected visual acuity at Day 180. Adverse events were consistent with the known safety profile of ocriplasmin. CONCLUSION: Ocriplasmin is effective for resolution of VMT without or with MH (≤400 µm); treatment outcomes can be optimized with patient selection.

Efficacy of Multiple Dexamethasone Intravitreal Implants for Refractory Retinal Vein Occlusion-Related Macular Edema and Effect of Prior Vitrectomy.

Purpose: To evaluate the efficacy of dexamethasone intravitreal implants (DEX implant) in patients with treatment-resistant macular edema (ME) owing to branch and central retinal vein occlusion (BRVO/CRVO), and the influence of prior vitrectomy on this treatment. Methods: Multicenter retrospective chart review was performed on 40 CRVO and 32 BRVO eyes with persistent ME despite intravitreal anti-vascular endothelial growth factor agents and/or intravitreal triamcinolone, and/or laser therapy. Each patient received ≥1 dexamethasone 700 µg implant between March 2011 and December 2015. Thirteen patients underwent prior vitrectomy. Data were collected on best-corrected visual acuity (BCVA), central macular thickness (CMT), time to relapse, and adverse events. Results: At the end of follow-up, BRVO eyes had a lesser CMT reduction from baseline compared to CRVO eyes (-122.50 ± 152.47 µm and -202.26 ± 194.09 µm, respectively). Neither BRVO nor CRVO eyes had a sustained BCVA benefit (P = 0.7041 and P = 0.7027, respectively). Vitrectomized and nonvitrectomized eyes overall had a sustained significant CMT reduction throughout the study with -192.46 ± 172.62 µm and -164.02 ± 180.36 µm, respectively, at final follow-up. Similar time to relapse of 24.4 ± 6.5 and 23.3 ± 13.5 weeks, respectively, was observed. By the end of follow-up, BCVA had only improved in vitrectomized eyes. However, multivariable regression analyses showed no significant association between vitrectomy status and CMT or BCVA change after the first and last injection. Cataract formation and ocular hypertension occurred in 25% and 17%, respectively. Conclusions: Multiple DEX implant are effective in reducing CMT in patients resistant to previous treatments and appear to be similarly effective in vitrectomized and nonvitrectomized eyes.