Eyelid implant

FIGURE 17.1 (a) Gold eyelid implant for the treatment of nerve paralysis, (b) Gold middle ear implants. 

Increasingly, biopotentials have to be measured within implanted devices and need to be transmitted to an external monitor or controller. Such applications include cardiac pacemakers transmitting the intracardiac ECG and functional electrical stimulation where, for example, action potentials measured at one eyelid serve to stimulate the other lid to restore the physiological function of a damaged lid at least to some degree. In these applications, the power consumption of the implanted biopotential amplifier hmits the life span of the implanted device. The usual solution to this problem is an inductive transmission of power into the implanted device that serves to recharge an implanted battery. In applications where the size of the implant is of concern, it is desirable to eliminate the need for the battery and the related circuitry by using a quasi-passive biopotential amplifier, that is, an amplifier that does not need a power supply. 

Figure 21.8 Model of human skull with a possible implementation of an implantable EPAM actuator for eyelid reanimation. The arrow indicates the EPAM module with slings for the upper and lower eyelids (Reprinted with permission from Laryngoscope, Restoration of Eyelid Closure in Eacial Paralysis Using Artificial Muscle Preliminary Cadaveric Analysis by Tollefson, T.T. and Senders, C.W, 117, 11, 1907-11. Copyright (2007) Lippincott, Williams and Wilkins).

An allergic hypersensitivity reaction -generalized itching, erythema and oedema of the eyelids — occurred with Dextran 70 during hysteroscopy for removal of an implanted Daikon shield. No previous exposure to dextran was known to the patient. Dextran was given to prevent anticipated bleeding (34 ). 

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