Currently, handles used in conjunction with compact (e.g., hand-held) diagnostic instruments, such as ophthalmoscopes and otoscopes, are based on dated designs and technologies that are at least 10 years old or more. For example, a number of known instrument designs, such as those manufactured by Welch Allyn Inc., of Skaneateles Falls, N.Y., among others, include features such as a rheostat that is provided on the instrument handle and is used to adjust illumination levels of a contained light source, such as a miniature halogen or other incandescent lamp. The latter feature adds to the complexity of the overall unit and requires a relatively large number of components to produce same, wherein it has been determined in certain settings that relatively few customers may actually use or require the benefit of the rheostat feature.
In the design of typical hand-held diagnostic medical instruments, such as ophthalmoscopes and otoscopes, a metal base or top cap is utilized. To insure the tight tolerances required for these instruments, these parts are machined from materials such as brass. Machining adds significantly to the overall cost of the instrument. It has been a goal in the field to produce a lower cost, but equally reliable diagnostic instrument. Lower cost instruments, such as those manufactured by Heine Optotechnik, Riester, and others utilize a molded plastic approach that includes a simple on/off switch. A plastic housing or handle, however, can leave customers with a perception of inferior quality.