Clinical aspects of aphakic retinal detachment

Aphakic retinal detachment occurred most frequently in the first year following cataract extraction and more common among old males than females. Vitreous complications during cataract extraction was a predisposing factor with higher incidence of PVR when the detachment occurred. The retina was totally detached with macular involvement in most of the cases. There was higher incidence of temporal retinal breaks than that of nasal breaks

Preprogrammed pid controller for the glucose homeostasis system

The regulation of the glucose in the metabolic system was achieved, based on a 4th order well identified digital model, and a predetermined digital control. Assuming the model is sufficiently accurate to avoid the need for measurement of the glucose concentration an open- loop digital controller is designed. A partial pole placement technique together with the dominant roots concept are used to synthesize the discrete time controller. The parameters of the controller are determined from the solution of a set of linear simultaneous equations. The closed-loop dynamics are dictated by the type of the dominant poles. A set of well behaved responses and internal states were obtained with variable overshoot. The dynamics have shown to be comparatively fast and the controller was shown to be robust using the bounding polynomials suggested by Kharitonov's stability criterion

open-loop digital controller for the glucoregulatory system by insulin therapy

Based on a fourth order digital model of the experimentally validated gluccregulatory system derived from the state differential equations which represent the system metabolism, a proportional-integral- derivative controller was achieved, that restores and maintains the normal glucose concentration in the human subject. The controller uses as a reference, a ramp function followed by step input, to overcome the large peak undershoot of the conditionally stable metabolic system. The control strategy was to optimize the controller parameters and the switching time [time at which the reference switches] simultaneously, such that, dynamics which are comparatively fast with small undamped terms are achieved. The controller parameters are determined from the solution of a set of linear simultaneous equations, based on a partial pole placement technique. Three sets of well behaved responses and internal states were obtained with variable peak undershoot. The robustness property of the controller was measured using the bounding polynomials suggested by Kharitonov's stability criterion

management of branch retinal vein occlusion

Twenty-six eyes having branch retinal vein occlusion have been managed and followed up for 6-12 months. Twelve eyes having neither macular oedema nor ocular neovascularization were medically treated with calcium dobesilate [doxium] and pentosan sulfuric polyester [hemoclar]. 75% Improved, 16.66% developed fundus neovascularization, and 8.34% developed macular oedema. The best results were achieved when treatment was started early. Fourteen eyes, of which 8 presented with macular oedema and 6 presented with fundus neovascularization were treated by photocoagulation of the affected quadrant. Regression of macular oedema occurred in 75% of the cases, visual improvement was achieved in 25% and stabilization in 50%. Progression of oedema and visual deterioration occurred in 25% of the cases. 83.33% of the eyes having neovascularization pronounced closure of neovessels with stabilization of vision, the remaining 16.67% deteriorated