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Kamiar Mireskandari - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children
    American journal of ophthalmology, 2015
    Co-Authors: Paulita Pamela Astudillo, Melissa Cotesta, Jennifer Schofield, Stephen P. Kraft, Kamiar Mireskandari
    Abstract:

    Purpose To determine if achieving the ideal postoperative Target range increases the long-term success of pediatric strabismus surgery. Design Interventional case series. Methods Children below 12 years old with horizontal strabismus who underwent surgical correction by recession, resection, advancement, or a combination of both between 1996 and 2011 were included. Alignment was measured within 1 week and at a minimum of 6 months after surgery. The ideal postoperative Target range was defined as 0–8 prism diopters (PD) of esotropia in exotropic patients and within 4 PD of orthotropia in esotropic patients measured within 1 week after the surgery. Success was defined as a measurement within 10 PD of orthotropia at the latest postoperative visit. The main outcome measures were surgical success rate and the factors affecting it. Results We included 352 patients with mean follow-up of 18 months. Overall, patients within the Target range had a higher success rate than those outside it (75.6% vs 57% P  = .0004). This was highly significant for exotropia ( P  = .0002) but not for esotropia ( P  = .4). Multiple regression analysis revealed that being within Target range was the strongest predictor of long-term success (odds ratio [OR] = 2.3, range 1.4–3.7). Overall, surgeries on patients with esotropia were more likely to be successful than on those with exotropia (OR = 1.9, range 1.2–3), and premature patients had poorer outcomes (OR = 0.2, range 0.1–0.8). Conclusion Achieving the ideal Target range within 1 week after surgery is associated with a high rate of long-term success in exotropia surgery in children.

  • Achieving postoperative Target range increases success of strabismus surgery in adults: a case for adjustable sutures?
    The British journal of ophthalmology, 2015
    Co-Authors: Kamiar Mireskandari, Jennifer Schofield, Melissa Cotesta, Derek Stephens, Stephen P. Kraft
    Abstract:

    Background/aims To evaluate the role of achieving immediate Target Angles on the success of strabismus surgery. Methods We performed a retrospective cohort study of all patients over 12 years old undergoing strabismus surgery with either adjustable or non-adjustable sutures. Target Angle for patients with esotropia and vertical deviation was within 4 prism dioptres (PD) of orthotropia and for patients with exotropia between orthotropia and 8 PD of esotropia. Success was defined as alignment within 10 PD for horizontal rectus surgery and within 5 PD of orthotropia for vertical rectus surgery, without diplopia or reoperations. The main outcome measure was surgical success rate. Results Three hundred and fifty-three patients were included in the study with mean follow-up of 13.9 (4–132) months. Patients achieving the Target Angle immediately postoperatively had higher success rate than patients who did not (83.6% vs 63.7%, p Conclusions Our results suggest that achieving the immediate Target Angle is the most significant factor in the success of strabismus surgery for exotropia. Adjustable suture surgery results in higher proportion of patients achieving this Target Angle.

Stephen P. Kraft - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children
    American journal of ophthalmology, 2015
    Co-Authors: Paulita Pamela Astudillo, Melissa Cotesta, Jennifer Schofield, Stephen P. Kraft, Kamiar Mireskandari
    Abstract:

    Purpose To determine if achieving the ideal postoperative Target range increases the long-term success of pediatric strabismus surgery. Design Interventional case series. Methods Children below 12 years old with horizontal strabismus who underwent surgical correction by recession, resection, advancement, or a combination of both between 1996 and 2011 were included. Alignment was measured within 1 week and at a minimum of 6 months after surgery. The ideal postoperative Target range was defined as 0–8 prism diopters (PD) of esotropia in exotropic patients and within 4 PD of orthotropia in esotropic patients measured within 1 week after the surgery. Success was defined as a measurement within 10 PD of orthotropia at the latest postoperative visit. The main outcome measures were surgical success rate and the factors affecting it. Results We included 352 patients with mean follow-up of 18 months. Overall, patients within the Target range had a higher success rate than those outside it (75.6% vs 57% P  = .0004). This was highly significant for exotropia ( P  = .0002) but not for esotropia ( P  = .4). Multiple regression analysis revealed that being within Target range was the strongest predictor of long-term success (odds ratio [OR] = 2.3, range 1.4–3.7). Overall, surgeries on patients with esotropia were more likely to be successful than on those with exotropia (OR = 1.9, range 1.2–3), and premature patients had poorer outcomes (OR = 0.2, range 0.1–0.8). Conclusion Achieving the ideal Target range within 1 week after surgery is associated with a high rate of long-term success in exotropia surgery in children.

  • Achieving postoperative Target range increases success of strabismus surgery in adults: a case for adjustable sutures?
    The British journal of ophthalmology, 2015
    Co-Authors: Kamiar Mireskandari, Jennifer Schofield, Melissa Cotesta, Derek Stephens, Stephen P. Kraft
    Abstract:

    Background/aims To evaluate the role of achieving immediate Target Angles on the success of strabismus surgery. Methods We performed a retrospective cohort study of all patients over 12 years old undergoing strabismus surgery with either adjustable or non-adjustable sutures. Target Angle for patients with esotropia and vertical deviation was within 4 prism dioptres (PD) of orthotropia and for patients with exotropia between orthotropia and 8 PD of esotropia. Success was defined as alignment within 10 PD for horizontal rectus surgery and within 5 PD of orthotropia for vertical rectus surgery, without diplopia or reoperations. The main outcome measure was surgical success rate. Results Three hundred and fifty-three patients were included in the study with mean follow-up of 13.9 (4–132) months. Patients achieving the Target Angle immediately postoperatively had higher success rate than patients who did not (83.6% vs 63.7%, p Conclusions Our results suggest that achieving the immediate Target Angle is the most significant factor in the success of strabismus surgery for exotropia. Adjustable suture surgery results in higher proportion of patients achieving this Target Angle.

  • preoperative prism adaptation in acquired esotropia with convergence excess
    Journal of Aapos, 2003
    Co-Authors: Tamara Wygnanskijaffe, Stephen P. Kraft, Jennifer Trotter, Patrick Watts, Mohamad Abdolell
    Abstract:

    Abstract Purpose The prism adaptation test (PAT) is used preoperatively to determine the surgical Target Angle for acquired esotropia. We assessed the surgical outcomes for children with convergence-excess esotropia (near esotropia greater than distance esotropia by 10 prism diopters [PD] or more) whose Target Angle was based on the results of the PAT geared to the near deviation. Methods We reviewed the charts for all of one surgeon’s patients who underwent the PAT for near convergence-excess esotropia and who were followed-up for at least 6 months after surgery. Patients who wore prisms were classified as PAT responders (esotropia Results Fifty-four (83%) of the 65 children were PAT responders. Thirty-nine (72%) of the 54 responders and 6 (55%) of 11 nonresponders had excellent results (heterotropia Conclusions PAT for the near deviation in children who have convergence-excess esotropia is a useful test in estimating the Target Angle for surgery. Responders whose Angles built with prism had a particularly high success rate. Surgery geared to the near-adapted Angle has a low risk of creating an overcorrection in the distance regardless of the response to PAT.

Jennifer Schofield - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children
    American journal of ophthalmology, 2015
    Co-Authors: Paulita Pamela Astudillo, Melissa Cotesta, Jennifer Schofield, Stephen P. Kraft, Kamiar Mireskandari
    Abstract:

    Purpose To determine if achieving the ideal postoperative Target range increases the long-term success of pediatric strabismus surgery. Design Interventional case series. Methods Children below 12 years old with horizontal strabismus who underwent surgical correction by recession, resection, advancement, or a combination of both between 1996 and 2011 were included. Alignment was measured within 1 week and at a minimum of 6 months after surgery. The ideal postoperative Target range was defined as 0–8 prism diopters (PD) of esotropia in exotropic patients and within 4 PD of orthotropia in esotropic patients measured within 1 week after the surgery. Success was defined as a measurement within 10 PD of orthotropia at the latest postoperative visit. The main outcome measures were surgical success rate and the factors affecting it. Results We included 352 patients with mean follow-up of 18 months. Overall, patients within the Target range had a higher success rate than those outside it (75.6% vs 57% P  = .0004). This was highly significant for exotropia ( P  = .0002) but not for esotropia ( P  = .4). Multiple regression analysis revealed that being within Target range was the strongest predictor of long-term success (odds ratio [OR] = 2.3, range 1.4–3.7). Overall, surgeries on patients with esotropia were more likely to be successful than on those with exotropia (OR = 1.9, range 1.2–3), and premature patients had poorer outcomes (OR = 0.2, range 0.1–0.8). Conclusion Achieving the ideal Target range within 1 week after surgery is associated with a high rate of long-term success in exotropia surgery in children.

  • Achieving postoperative Target range increases success of strabismus surgery in adults: a case for adjustable sutures?
    The British journal of ophthalmology, 2015
    Co-Authors: Kamiar Mireskandari, Jennifer Schofield, Melissa Cotesta, Derek Stephens, Stephen P. Kraft
    Abstract:

    Background/aims To evaluate the role of achieving immediate Target Angles on the success of strabismus surgery. Methods We performed a retrospective cohort study of all patients over 12 years old undergoing strabismus surgery with either adjustable or non-adjustable sutures. Target Angle for patients with esotropia and vertical deviation was within 4 prism dioptres (PD) of orthotropia and for patients with exotropia between orthotropia and 8 PD of esotropia. Success was defined as alignment within 10 PD for horizontal rectus surgery and within 5 PD of orthotropia for vertical rectus surgery, without diplopia or reoperations. The main outcome measure was surgical success rate. Results Three hundred and fifty-three patients were included in the study with mean follow-up of 13.9 (4–132) months. Patients achieving the Target Angle immediately postoperatively had higher success rate than patients who did not (83.6% vs 63.7%, p Conclusions Our results suggest that achieving the immediate Target Angle is the most significant factor in the success of strabismus surgery for exotropia. Adjustable suture surgery results in higher proportion of patients achieving this Target Angle.

Melissa Cotesta - One of the best experts on this subject based on the ideXlab platform.

  • The Effect of Achieving Immediate Target Angle on Success of Strabismus Surgery in Children
    American journal of ophthalmology, 2015
    Co-Authors: Paulita Pamela Astudillo, Melissa Cotesta, Jennifer Schofield, Stephen P. Kraft, Kamiar Mireskandari
    Abstract:

    Purpose To determine if achieving the ideal postoperative Target range increases the long-term success of pediatric strabismus surgery. Design Interventional case series. Methods Children below 12 years old with horizontal strabismus who underwent surgical correction by recession, resection, advancement, or a combination of both between 1996 and 2011 were included. Alignment was measured within 1 week and at a minimum of 6 months after surgery. The ideal postoperative Target range was defined as 0–8 prism diopters (PD) of esotropia in exotropic patients and within 4 PD of orthotropia in esotropic patients measured within 1 week after the surgery. Success was defined as a measurement within 10 PD of orthotropia at the latest postoperative visit. The main outcome measures were surgical success rate and the factors affecting it. Results We included 352 patients with mean follow-up of 18 months. Overall, patients within the Target range had a higher success rate than those outside it (75.6% vs 57% P  = .0004). This was highly significant for exotropia ( P  = .0002) but not for esotropia ( P  = .4). Multiple regression analysis revealed that being within Target range was the strongest predictor of long-term success (odds ratio [OR] = 2.3, range 1.4–3.7). Overall, surgeries on patients with esotropia were more likely to be successful than on those with exotropia (OR = 1.9, range 1.2–3), and premature patients had poorer outcomes (OR = 0.2, range 0.1–0.8). Conclusion Achieving the ideal Target range within 1 week after surgery is associated with a high rate of long-term success in exotropia surgery in children.

  • Achieving postoperative Target range increases success of strabismus surgery in adults: a case for adjustable sutures?
    The British journal of ophthalmology, 2015
    Co-Authors: Kamiar Mireskandari, Jennifer Schofield, Melissa Cotesta, Derek Stephens, Stephen P. Kraft
    Abstract:

    Background/aims To evaluate the role of achieving immediate Target Angles on the success of strabismus surgery. Methods We performed a retrospective cohort study of all patients over 12 years old undergoing strabismus surgery with either adjustable or non-adjustable sutures. Target Angle for patients with esotropia and vertical deviation was within 4 prism dioptres (PD) of orthotropia and for patients with exotropia between orthotropia and 8 PD of esotropia. Success was defined as alignment within 10 PD for horizontal rectus surgery and within 5 PD of orthotropia for vertical rectus surgery, without diplopia or reoperations. The main outcome measure was surgical success rate. Results Three hundred and fifty-three patients were included in the study with mean follow-up of 13.9 (4–132) months. Patients achieving the Target Angle immediately postoperatively had higher success rate than patients who did not (83.6% vs 63.7%, p Conclusions Our results suggest that achieving the immediate Target Angle is the most significant factor in the success of strabismus surgery for exotropia. Adjustable suture surgery results in higher proportion of patients achieving this Target Angle.

Yawu Wang - One of the best experts on this subject based on the ideXlab platform.

  • Virtual Model Reduction-based Control Strategy of Planar Three-link Underactuated Manipulator with Middle Passive Joint
    International Journal of Control Automation and Systems, 2020
    Co-Authors: Zixin Huang, Xuzhi Lai, Pan Zhang, Yawu Wang
    Abstract:

    This paper presents a position control strategy for a planar active-passive-active (APA) underactuated manipulator with second-order nonholonomic characteristics. According to the structural characteristics of the planar APA system, we divide the system into two parts: a planar virtual Pendubot (PVP) and a planar virtual Acrobot (PVA). For the PVP, we mainly fulfill the Target Angle of the first link, which is calculated through the geometry method, and make the system stable. In this stage, via keeping the states of the third link being zero, the system is reduced to the PVP. Meanwhile, we design an open-loop control law based on the nilpotent approximation (NA) model of the PVP to make the second link stable and the first link stabilize at its Target Angle. Then, the planar APA system is reduced to a PVA with all links’ angular velocities being zero. For the PVA, we mainly realize the other two links’ Target Angles obtained via the particle swarm optimization (PSO) algorithm. Thus, the control objective of the planar APA system is achieved. Finally, above control strategy is verified by simulation results.

  • Position and posture control for a planar underactuated manipulator based on model reduction and chained structure
    SCIENTIA SINICA Informationis, 2020
    Co-Authors: Dong Liu, Xiongbo Wan, Yawu Wang, Xuzhi Lai
    Abstract:

    A control strategy is proposed based on the model reduction and the chained structure for a planar four-link (Active-Active-Passive-Active, AAPA) underactuated manipulator to achieve its position-posture control objective. The whole control process is divided into three stages. In the first stage, the planar AAPA manipulator is reduced to the planar virtual three-link (Active-Active-Passive, AAP) manipulator by controlling the Angle of the fourth link and rotating it to zero. In the second stage, the model of a planar virtual AAP manipulator is transformed into the standard chain structure form. Then, the corresponding controllers are designed to control the passive joint of the planar virtual AAP manipulator to its Target position, and the posture Angle of the passive link is controlled to its middle posture Angle at the same time. At the end of this stage, the planar AAPA manipulator is reduced to the planar Acrobot. In the third stage, the Angle of the active link of the planar Acrobot is controlled to its Target Angle. Also, the Angle control of the passive link of the system is realized. Consequently, the position-posture control objective of the planar AAPA manipulator is recognized. Considering the Angle constraint of the planar Acrobot, the genetic algorithm is used to coordinate and optimize the Target Angle of the passive joint, the middle posture Angle of the passive link, the Target Angle of the fourth link, and the Target posture Angle of the passive link. These ensure the Target Angles of the planar Acrobot corresponding to the Target position-posture of the system can be found. Finally, simulation results demonstrate the effectiveness of the proposed control strategy.

  • Position and Posture Control of Planar Four-Link Underactuated Manipulator Based on Neural Network Model
    IEEE Transactions on Industrial Electronics, 2020
    Co-Authors: Jinhua She, Yawu Wang
    Abstract:

    This paper presents a control strategy for the position and posture control of a planar four-link underactuated manipulator with a passive second link based on a back-propagation neural network (BPNN) model. First, using the differential evolution (DE) optimization algorithm, the Target Angles of all links are calculated. The third and fourth links are then controlled from their initial Angles to zero. Next, the control process is divided into the following two steps: the control objective of the passive link is implemented in the first step, and the control objectives of the active links are implemented in the second step. In the first step, the system is reduced to a planar virtual Pendubot, a BPNN model based on the DE algorithm is trained to obtain the coupling relationship between the links of this Pendubot. This model gives the speed of the first link to move the passive link to approach the Target Angle. Then, a fuzzy controller is designed to indirectly control the passive link to its Target Angle. In the second step, the position mode of the servo controller is adopted to control all active links to their Target Angles. Experimental results verified the effectiveness of the proposed control strategy.

  • Control strategy based on differential evolution algorithm for planar second-order nonholonomic manipulator
    2018 37th Chinese Control Conference (CCC), 2018
    Co-Authors: Yawu Wang, Xuzhi Lai, Pan Zhang
    Abstract:

    This paper presents a two-stage position control strategy based on the differential evolution (DE) algorithm for a planar second-order nonholonomic manipulator, which has one passive joint and this passive joint is not the first joint (planar $\mathrm{A}^{\mathrm{m}}\mathrm{PA}^{\mathrm{n}}$ manipulator for short, where $m\geq 1, n\geq 0$ ). An offline DE algorithm is used to calculate all link Target Angles corresponding to the Target position. According to these Target Angles, a Lyapunov function is constructed to design the controllers A for the control stage 1, which are used to control all active links to their Target Angles. According to the constraint equation of the planar $\mathrm{A}^{\mathrm{m}}\mathrm{PA}^{\mathrm{n}}$ manipulator, an oscillatory trajectory is planned for the first active link based on the online DE algorithm. When the first active link tracks the oscillatory trajectory, it will back to its Target Angle eventually. Meantime, the passive link will be jointly controlled to its Target Angle eventually. Then, the other Lyapunov function is constructed to design the controllers B for the control stage 2, which are used to control the first active link tracks the Target trajectory and control the remaining $m+n-1$ active links maintain in their Target Angles. Simulation results of a planar AAPA manipulator demonstrate the effectiveness of the proposed control strategy.