DESIGN OF A SCLERAL DEPRESSOR

摘要

The use of lasers for eye surgery has become quite common. The concept behind laser treatment is to introduce and control a coherent light source which transforms diseased areas of the retina into minute scars from very small burned areas. This process is called photocoagulation and lends itself to the treatment of several diseases including glaucoma, retinal tumors, and symptoms associated with diabetes [1]. Ophthalmologists use a variety of lens types during surgeries. These are broadly referred to as contact lenses since they are placed in direct contact with the cornea. In many cases it is necessary to examine or treat regions of the eye which are located in the anterior portion of the eye's interior. To improve visibility in these cases contact lenses incorporating angled mirrors are used (see Fig. 1). Even with the use of these mirrored lenses, certain longitudes of the eye can only be examined by depressing the sclera, or white portion of the eye. The effect of this scleral depression is to move the area of interest into the path of the laser beam (Fig. 2). Typically, the depressor instrument is simply hand held steel rod with a curved end. The preferred method of performing laser surgery is with a apparatus called a slitlamp. The patient sits on one side of the slitlamp and places his forehead and chin on rests which reduce inadvertent motions. The doctor sits on the opposite side of the device and manipulates a joystick which controls both focus and aiming functions. With his remaining freehand the doctor can reach around the slitlamp and hold a contact lens against the patient's cornea. When desired, the laser can be fired by a foot control. A serious shortcoming with this arrangement arises when scleral depression is required. It is awkward for the doctor to have to reach around the slitlamp with both hands. Moreover, spatial constraints can prevent access to certain clock hours of the eye.