APPENDIX B: USE OF THE DIRECT OPTHALMOSCOPE

The direct ophthalmoscope is designed to use the patient’s own optical system to magnify the optic disc and retina for diagnostic purposes, but it has multiple additional uses, such as obtaining a magnified view of the anterior segment, evaluating for visually significant cataract, and evaluating pupil responses in uncooperative or pediatric patients.

Equipment: Direct Ophthalmoscope

Techniques:

- To obtain a magnified view of the anterior segment of the eye. Viewing from 2-3 inches from the eye using the plus lenses (black or green numbers, ~5) will provide an enlarged view when evaluating for foreign bodies or corneal abrasions. Using the cobalt blue filter with fluorescein dye will enhance the view of corneal epithelial defects.
- To evaluate for cataracts, stand approximately 1 meter from the patient and evaluate the red reflex from the retina with no lens dialed in (no red or green numbers). Blockage of the red reflex will highlight any visually significant cataracts.
- To check for pupil reactivity in uncooperative patients or children, view the red reflex from 2-3 feet (again with no lenses dialed in); movie the light from one eye to the other and observe the change in the size of the red reflex.
- Assessment of retinal spontaneous venous pulsations may be possible in the setting of traumatic brain injury.25