Background Scleral buckling is typically implemented to repair rhegmatogenous retinal detachments (RRD) in young patients. Therefore, there is limited data on post-pars plana vitrectomy (PPV) cataract formation in this cohort. We report the rates and risk factors of cataract progression after PPV for RRD repair in young eyes. Methods Retrospective single-center cohort study. Medical records of patients between the ages of 15 to 45 undergoing PPV for uncomplicated RRD between 2014 and 2020 were reviewed. Results Twenty-eight eyes from 26 patients met inclusion criteria. Cataracts developed in 20/28 (71%) eyes after PPV. After PPV, nuclear sclerotic cataract (NSC) rates were higher in patients above 35 (65%) compared to below 35 years (18%) ( p = 0.024). Cataracts developed more frequently after macula-off RRDs (88%) compared to macula-on RRDs (50%) ( p = 0.044) with NSC more common in macula-off detachments ( p = 0.020). At postoperative month 2, all eyes with C 3 F 8 gas developed cataracts compared to 59% of eyes with no gas ( p = 0.040). Conclusions Cataract formation was common and frequent after PPV. After PPV, young eyes and macula-on detachments developed cataracts less frequently than older eyes and macula-off detachments. If appropriate, a shorter acting gas tamponade should be considered in young eyes to minimize cataract formation.
Background Scleral buckling has been the standard for rhegmatogenous retinal detachment repair in young patients given the typical lack of posterior vitreous detachment, phakic status, and lower risk of proliferative vitreoretinopathy. In older patients, pars plana vitrectomy alone is typically used for rhegmatogenous retinal detachment repair. We report the outcomes and complications of pars plana vitrectomy for rhegmatogenous retinal detachment in young eyes. Methods Retrospective, single-center cohort study. Medical records of patients between 15 to 45 years of age undergoing primary pars plana vitrectomy for rhegmatogenous retinal detachment repair between 2010 and 2020 were carefully reviewed. All analyses were performed using the Kruskal–Wallis tests for numeric covariates between age groups. Results Eyes were stratified by age: 15–24 (group 1, n = 10), 25–34 (group 2, n = 14), and 35–45 (group 3, n = 38). The average number of surgeries were 1.9, 1.4, and 1.1 in groups 1, 2, and 3, respectively (p = 0.004). Single surgery success rates were 50%, 64%, and 92% in groups 1, 2 and 3, respectively (p = 0.005). Final reattachment rates were 80%, 93%, 100% in groups 1, 2, and 3, respectively (p = 0.568). Proliferative vitreoretinopathy developed in 50%, 7%, and 8% of eyes in groups 1, 2, and 3, respectively (p < 0.001). Conclusion While the final reattachment rates were excellent in all groups, the higher rates of proliferative vitreoretinopathy and lower single surgery success rate in younger patients may suggest that primary pars plana vitrectomy may not be the optimal repair method in these age groups.
Intravitreal anti-vascular endothelial growth factor (VEGF) injections are commonly used to treat eyes with macular edema secondary to hemiretinal vein occlusion (HRVO) or central retinal vein occlusion (CRVO). Information on whether differences exist in outcomes after anti-VEGF therapy can help guide treatment for each of the different disease types.To compare baseline characteristics, treatment burden, and outcomes of macular edema treatment in participants with HRVO with those of participants with CRVO.This post hoc outcome analysis from the Study of Comparative Treatments for Retinal Vein Occlusion 2 randomized clinical trial included 362 participants with macular edema caused by HRVO or CRVO treated at 66 US sites. Randomization began in September 2014, and the last month 24 follow-up visit occurred in February 2018. Data were analyzed from April 2020 to May 2021.Eyes were initially randomized to 6 monthly intravitreal injections of aflibercept or bevacizumab and were treated according to protocol between months 6 to 12 depending on 6-month outcome. After month 12, patients were treated per investigator discretion and observed through month 60.Mean visual acuity letter score (VALS).Of 362 included patients, 157 (43.4%) were female, and the mean (SD) age was 68.9 (12.0) years. Outcome data were analyzed up to month 24 owing to substantial missing data at later visits. A significantly greater proportion of participants with HRVO than those with CRVO were Black (37% vs 11%). Treatment rates between months 12 to 23 were 0.36 (95% CI, 0.32-0.40) injections per month for patients with CRVO and 0.28 (95% CI, 0.19-0.36) for patients with HRVO (P = .11). The mean VALS from months 1 to 24 of an HRVO study eye exceeded that of a CRVO study eye by 5.5 (95% CI, 1.5-9.5; P = .01), consistent with the magnitude of the VALS difference between eyes with CRVO and HRVO at baseline. Eyes with CRVO presented at baseline with more macular edema than eyes with HRVO (difference in central subfield thickness [CST], 86 μm; 95% CI, 48-124; P < .001), with no difference in CST between the groups throughout months 1 to 24.Black race was more prevalent among participants with HRVO than CRVO, and no differences were observed in the frequency of treatments for macular edema between eyes with CRVO and HRVO. Although eyes with CRVO presented with worse visual acuity and more macular edema on average than did eyes with HRVO, the magnitude of VALS improvement, central retinal thickness in response to anti-VEGF therapy, and treatment burden were similar between the groups.
ImportanceTwo-year outcomes are reported comparing eyes originally assigned to aflibercept or bevacizumab to assess the need for continued anti-vascular endothelial growth factor (VEGF) therapy for macular edema due to central retinal vein occlusion (CRVO) or hemiretinal vein occlusion (HRVO) from participants in the Study of Comparative Treatments for Retinal Vein Occlusion 2 (SCORE2) trial.ObjectiveTo investigate outcomes 1 year after cessation of the SCORE2 treatment schedule.Design, Setting, and ParticipantsIn this secondary analysis of the SCORE2 randomized clinical trial, follow-up included 117 participants originally randomized to aflibercept and 119 participants originally randomized to bevacizumab between September 17, 2014, and November 18, 2015. Data for the analyses were frozen on September 13, 2018.InterventionsSCORE2 participants completed the treatment protocol at month 12, were subsequently treated at investigator discretion, and underwent assessment at month 24.Main Outcomes and MeasuresVisual acuity letter score (VALS) and central subfield thickness (CST) on spectral-domain optical coherence tomography.ResultsAmong 362 participants randomized to aflibercept or bevacizumab, 65.2% (236 of 362) completed a protocol visit at month 24 (mean [SD] age, 68.5 (12.0) years; 53.8% male). The mean (SD) VALS improved from baseline to 12 months by 21.6 (14.5) in the aflibercept group compared with 21.9 (16.6) in the bevacizumab group (difference, -0.3; 99% CI, -5.6 to 4.9), then worsened from those values by a mean (SD) VALS of 7.6 (17.5) in the aflibercept group and 7.5 (14.5) in the bevacizumab group (difference, -0.1; 99% CI, -5.6 to 5.3) at month 24. The mean (SD) CST improved from baseline to 12 months by 394 (231) μm in the aflibercept group compared with 420 (274) μm in the bevacizumab group (difference, 26 μm; 99% CI, -62 to 114 μm), then worsened from those values by a mean (SD) of 58 (192) μm in the aflibercept group compared with 48 (186) μm in the bevacizumab group (difference, 10 μm; 99% CI, -58 to 78 μm) at month 24.Conclusions and RelevanceNo differences in VALS or CST outcomes at month 24 were identified when participants originally assigned to aflibercept were compared with those assigned to bevacizumab. Caution in interpretation is needed because of loss to follow-up. In both groups, VALS and CST improved through month 12 and then worsened somewhat during the second year, when treatment was at investigator discretion. This analysis suggests that CRVO and HRVO warrant close monitoring and treatment as needed over at least 2 years to optimize outcomes in eyes treated with anti-VEGF therapy.Trial RegistrationClinicalTrials.gov identifier: NCT01969708.
Purpose. Ischemic central retinal vein occlusion (CRVO) eyes are at high risk of developing neovascular glaucoma (NVG). Our purpose is to investigate the effect of anti-VEGF therapy for macular edema after CRVO on the development of neovascular glaucoma (NVG) in ischemic CRVO eyes. Methods. This is a retrospective case series of 44 eyes from 44 patients with CRVO treated with anti-VEGF therapy for macular edema. The primary outcome was the development of NVG. Results. Of the 44 eyes, 14 eyes had ischemic CRVO, and 30 eyes had nonischemic CRVO. Nonischemic eyes received a mean of 8.4 anti-VEGF doses, over mean follow-up of 24 months. One nonischemic eye (3.3%) developed NVD but not NVG. The 14 ischemic eyes received a mean of 5.6 anti-VEGF doses, with mean follow-up of 23 months. Of these 14 ischemic eyes, two eyes (14%) developed iris neovascularization and 3 eyes (21%) developed posterior neovascularization. Three of these 5 eyes with neovascularization progressed to NVG, at 19.7 months after symptom onset, on average. Conclusion. Anti-VEGF therapy for macular edema may delay, but does not prevent, the development of ocular NV in ischemic CRVO. Significant risk of NVG still exists for ischemic CRVO eyes.
This paper investigates the feasibility of a fuzzy logic control (FLC) algorithm for lateral control in a lane change maneuver in an automated highway system (AHS). The lane change maneuver takes the vehicle from lane following control in one lane to lane following control in an adjacent lane. It is assumed that there is no reference/sensing system in between the two lanes. The only sensor used for feedback during the lane change maneuver is a lateral accelerometer. The rules of the FLC are developed based on human driving experience. A simulation result is presented to show the feasibility of using the designed FLC for the lane change maneuver.
A Fuzzy logic controller (FLC) is designed and implemented in real time on a Toyota Celica test vehicle to achieve control of the lateral motion of the vehicle. The structure of the FLC is modularized as a feedback, preview, and gain scheduling rule base. The parameters of the FLC are tuned manually using information from characteristics of human driving operation and an existing controller. The fuzzy logic control strategies are implemented on the test vehicle, automatically following a multiple curved track using discrete magnetic markers as a lateral error reference system. The test results of the FLCs are shown with variations in driving conditions, and a comparison is made to similar tests conducted using the frequency shaped linear quadratic (FLSQ) controller with preview control.
Abstract A candidate for intelligent control for lateral guidance,of a vehicle is a fuzzy logic controller (FLC). The details of the most recent FLC with a rule base derived from heuristics and designer insight to the problem at hand, as well as a method for estimating a projected lateral displacement are presented along with simulation results. The structure of this FLC is suited to incorporate human,knowledge,about the steering operation , its
This report summarizes an experimental effort in integrating and testing an automated vehicle lateral control system. The project, a cooperative effort between the California Partners for Advanced Transit and Highway ( PATH) Program and IMRA America, Inc., included a discrete roadway reference system, on-vehicle magnetic sensing system, a computer control system and a hydraulic actuator.
An ongoing experimental research project focusing on vehicle lateral control is reported. This project is being jointly conducted by the University of California's PATH Program and IMRA America, Inc. The lateral control system to be tested uses the concept of cooperation between the vehicle-borne steering control system and a discrete magnetic reference system in the roadway. The components of this experimental setup are described. The analytical and experimental research conducted before this project on the various components are reviewed, some results of the completed tests are provided, and the planned tests are outlined.
The work presented in this paper addresses issues regarding the implementation of an integration of several specific technologies involved in achieving lateral guidance of an experimental automotive vehicle on an automated highway. Results are shown to demonstrate the feasibility of the proposed discrete magnetic marker reference/sensing system. In addition, the performance and limitations of a PID/feedforward controller is investigated with respect to tracking accuracy of straight and curved sections as well as robustness to changes in load, longitudinal velocity, and cornering stiffness.
A fuzzy rule-based controller is applied to lateral guidance of a vehicle for an automated highway system. The fuzzy rules, based on human drivers' experiences, are developed to track the center of a lane in the presence of external disturbances and over a range of vehicle operating conditions.