BIO Home Optics of BIO BIO Preparation BIO Observation
Patient Preparation
Explain the procedure to your patient. Give them an idea of what to expect during the examination.
The patient should know that the light is relatively bright.
Reassure the patient that the light will not harm them.
Explain to the patient that an eye exam with the BIO currently provides the most extensive and complete evaluation of the health of the inner eye.
Emphasize that dilating the pupils is a necessity even though it's inconvenient.
Recline the chair. This is the most efficient position for stereoscopic examination of the entire fundus and for scleral indentation. Patients with obvious back or neck injuries or disorders should be queried before reclining. Some may require examination in the seated position.
The face plane of the patient should be parallel to the floor. With the patient's face horizontally positioned, only small adjustments for obstructing physiognomy are necessary.
The room lights should be off, and extraneous sources of light should be excluded.
Begin the examination peripherally and then conclude with the posterior pole to enhance patient comfort. First begin with the superior portion of the patient's right eye (at 12 o'clock). The examiner's head is always positioned 180 degrees opposite the patient's direction of gaze to maximize peripheral viewing.
After the BIO light is directed into the pupil and a red reflex is observed, the +20 
D condensing lens is inserted into the light path about 2 inches from the eye, centered, and trombone until it fills with the image of the fundus.
Hold the condensing lens in your right hand while standing on the right side of the patient and change to your left hand when standing on the left side of the patient. Rest your other hand on the patient's forehead and use the thumb to retract the patient's upper lid (have the patient look down, grab the lid at its lash margin or by the lashes, and then have the patient look up). This gives you firm control of the upper lid. Remember that you retract the lower lid with the middle finger of the hand that holds the lens.
Stay at your working distance of 18 to 20 inches. There is a natural tendency for a beginner to want to continuously get closer to the patient. Don't do it.
Proceeding clockwise, the entire equatorial and mid peripheral areas of the right eye are examined. As the patient is directed to look into various positions of gaze, the examiner moves slightly so that the examiner's head is kept directly opposite the direction into which the patient is looking.
A systematic method is to start by standing on the patient's right side and by looking at the 12 o'clock position of the patient's superior retina. Tell the patient to look up at the top of his or her head. With your head at the 6 o'clock position (i.e., 180 degrees away), scan from the ora to the posterior pole. Then proceed clockwise by having the patient "look up and to the left," then "directly left toward the left ear," then "down and to the left shoulder," and then "straight down to the toes."
Next, walk around to the patient's left side and change the condensing lens to your left hand. Use the thumb of your right hand to gain control of the patient's upper lid. Ask the patient to "look down and to the right shoulder," then "directly right toward the right ear," then "up and to the right."
Finally, have the patient look at your chin so you can observe the optic nerve head and then ask the patient to "look at the light" to examine the fovea and macula. This finishes the right eye.
Still standing on the patient's left side, begin examining the patient's left eye by having the patient "look straight down," then "down and to the right shoulder," then "directly right toward the right ear," then "up and to the right," and then "straight up toward the top of the head."
Then walk back around to the patient's right side, exchanging hands again. Continuing to examine the retina clockwise, have the patient "look up and to the left," then "directly left toward the left ear," then "down toward the left shoulder." Finally, have the patient look at your chin and then at your light.
This procedure always involves moving clockwise, finishing the right eye completely before you start the left eye. This makes it easier to remember in which eye and where you saw lesions or noteworthy findings. As the patient's gaze is directed to the eight different positions, overlapping fields and, hence, the entire fundus will be viewed. This technique also allows the patient to light-adapt before you shine the light on the fovea and thus enhances cooperation.
Permit the patient to blink occasionally. The patient's eye becomes dry due to the lack of blinking and the prolonged exposure to a bright light. Rather than releasing your thumb's grip on the patient's upper lid and telling him or her to blink, you may simply use your thumb to close and then open the patient's eye periodically.
Fine lateral movements can be valuable in revealing parallactic views of the fundus or differentiating a shadow in the fundus image as being caused by an ocular media opacity or a lens fingerprint, for example. Parallax movements can be elicited by moving the condensing lens from side-to-side or in a circular motion. This will reveal elevation of intraocular structures above the level of the retina. For example, a posterior vitreous detachment can be revealed by noting the relative movement of small faint opacities of vitreous condensation.
It is difficult to maintain a stereoscopic, binocular view of the fundus in patients with very small pupils. Some brands of BIO include a convergence control which allows a binocular view in patients with pupil sizes as small as 2mm in diameter. Please see the owners manual that came with your scope for details on making this adjustment.
When examining the fundus, reflections from the two surfaces of the condensing 
lens can be minimized by slightly tilting the condensing lens.
Red-free filter. Reflections from the hyaloid face/internal limiting membrane interface will be somewhat dissipated with this filter (or the cobalt blue filter) in place. The red-free filter serves two other important functions. Observation of the nerve-fiber layer will be enhanced in green light. Because of the absorption spectrum of the melanin granules of the RPE, monochromatic green (red-free) light will be reflected. The clinical significance is that structures deep to the RPE will either disappear or become greatly attenuated in red-free light.
Blue filter. A cobalt blue filter can be used to enhance the detection of buried drusen of the optic nerve head due to their induced fluorescence. It could also be used for fluorescein angiography
Patient Considerations
Spreading the lids with the first and second fingers with a scissoring motion has the potential to cause a corneal abrasion in the very likely event of slippage. Using the second (middle) finger of the lens-holding hand and the opposite thumb affords much more positive control.
Allow the patient to blink occasionally.
Often patients are unable to direct their gaze into the intended field. There are three strategies that may make this easier.
Encourage the patient to keep both eyes open. Bell's movement causes the examined eye to roll up. Having the patient hold the eye is counterproductive since it intensifies the Bell's response.
Direct the patient's gaze toward some anatomical landmark. For example, say: "Look toward your right eye," "Look at your right shoulder," or "Look down toward your toes." Lightly tapping the patient's face in the desired direction also may be helpful.
If the other two strategies don't work, position the patient's thumb or hand in the direction you want them to look and have them stare at the thumb/hand.
Asking the patient to lift the chin often removes an obstructing brow from the condensing lens image. Similarly, asking the patient to tilt or turn his/her head provides a good binocular view past a large nose, for example.
Following the fundus survey, patients may report being unable to see or describe the perception of brightly colored (green, orange, purple) spots in the visual field. Tell the patient that this is a normal phenomenon and that it's analogous to the spots seen after looking at an electronic flash or flash bulb. In other words, there has been bleaching of retinal photo pigments and they will regenerate.
Issue the patient temporary disposable sunglasses at the end of the exam.
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