>> opt = optimset('TolX',1e-8,'Display','iter')

opt = 

  struct with fields:

                   Display: 'iter'
               MaxFunEvals: []
                   MaxIter: []
                    TolFun: []
                      TolX: 1.0000e-08
               FunValCheck: []
                 OutputFcn: []
                  PlotFcns: []
           ActiveConstrTol: []
                 Algorithm: []
    AlwaysHonorConstraints: []
           DerivativeCheck: []
               Diagnostics: []
             DiffMaxChange: []
             DiffMinChange: []
            FinDiffRelStep: []
               FinDiffType: []
         GoalsExactAchieve: []
                GradConstr: []
                   GradObj: []
                   HessFcn: []
                   Hessian: []
                  HessMult: []
               HessPattern: []
                HessUpdate: []
          InitBarrierParam: []
     InitTrustRegionRadius: []
                  Jacobian: []
                 JacobMult: []
              JacobPattern: []
                LargeScale: []
                  MaxNodes: []
                MaxPCGIter: []
             MaxProjCGIter: []
                MaxSQPIter: []
                   MaxTime: []
             MeritFunction: []
                 MinAbsMax: []
        NoStopIfFlatInfeas: []
            ObjectiveLimit: []
      PhaseOneTotalScaling: []
            Preconditioner: []
          PrecondBandWidth: []
            RelLineSrchBnd: []
    RelLineSrchBndDuration: []
              ScaleProblem: []
       SubproblemAlgorithm: []
                    TolCon: []
                 TolConSQP: []
                TolGradCon: []
                    TolPCG: []
                 TolProjCG: []
              TolProjCGAbs: []
                  TypicalX: []
               UseParallel: []