The Design And Construction Of A Homemade Binocular Indirect Ophthalmoscope.

As the scope of optometric practice expands toward a more comprehensive type of eye care, the need for additional skills and instrumentation is also required. One such skill is the examination of the peripheral fundus. The peripheral fundus is the area of the retina anterior to the equator and encompasses 40% of the ocular fundus. The binocular indirect ohthalmoscope (BIO) is the instrument of choice when examining this area. This instrument has many favorable features that make its use essential in order to do a complete and thorough fundus evaluation. As the number of states allowing diagnostic pharmaceutical agents (DPA's) increase, the utilization of the BIO becomes more and more practical. Not only does the BIO allow the practitioner to view the peripheral fundus, but it also permits him to observe a much larger area with a single view. The BIO provides a viewable area of approximately eight disc diameters compared to that of only two disc diameters with a
direct ophthalmoscope. In addition, the indirect ophthalmoscope, with its lesser magnification and aerial imagery, greatly reduces the visual distortions present when trying to view the peripheral fundus. The BIO also provides the examiner with stereopsis, invaluable when localizing and understanding the pathophysiology and progression of various fundus
lesions and media abnormalties.