Introduction

Fundus biomicroscopy is a technique used to evaluate the peripheral retina and posterior pole, usually through a dilated pupil.

Indications

Any instance where examination of the posterior pole/peripheral retina is required

Contra-Indications

Known sensitivities/allergies to topical ophthalmic mydriatic agents

Materials

1. 78D or 90D lens
2. Mydriatic agent such as tropicamide 1% (can be performed un-dilated)

Setup

1. Adjust patient platform height such that patient is comfortably situated
2. Adjust patient chin height such that lateral canthus is in line with canthal line
3. Adjust doctor stool height such that eyes are directly in line with oculars
4. Set ocular PD
5. Focus on temporal limbus with a 3 mm X 3 mm beam.  Hold focus, and have observer focus teaching tube
6. Turn light beam on low intensity; set to 6 mm high X 3 mm wide beam
7. Pull slit lamp until the back of the slit lamp is lined up with the back of the gray pad on the platform.  Center the beam of light horizontally and vertically over the patient’s pupil.
8. Have patient fixate straight ahead, or top of your opposite ear
9. Brace your elbow on the platform or on an appropriate block, then place 78D/90D lens directly in front of eye; look around the slit lamp on the nasal side of the lens and pull the lens back slightly to see where light falls on the patient’s eye.  Center projected light horizontally and vertically over pupil by moving the lens only (the slit lamp has not moved, and should still be centered) and “lock” your lens hand into position.
10. Move behind oculars – do you see a red reflex?

• • Yes – push slit lamp toward patient to focus, maintaining horizontal and vertical centration of red reflex
  • No – don’t move slit lamp (the slit lamp has not moved, so your light beam should still be centered).  Pull the lens toward you until you can make out the iris and pupil, then re-center lens over pupil to maximize red reflex.  Maintaining red reflex, push lens toward eye until positioned at the proper working distance (the closer you are, the wider your angle of view, and the easier your examination will be.  Too close, though, and you’ll hit the patient’s eyelashes, and they’ll want to blink).

If this doesn’t work, repeat step #9.

1. Once in focus, start your examination.  Your examination sequence should be: disc, macula, superior arcade (at least 5 DD from the disc), inferior arcade (at least 5 DD from the disc), nasal retina, and the posterior vitreous.

To move from one spot in the retina to another, start by moving your lens (or the slit lamp) such that it moves you closer to your desired target.  Then move the slit lamp (or lens) until you have maximized your view again.  Repeat until you arrive at your target location.

Results

Usually, you’ll record “No holes breaks tears 360 degrees”.

If you determine that pathology is present, document where and what, or, if you can’t determine what it is, describe it.

“CHRPE @ 1 OD”

“2 DD X 3 DD black and white lesion @ 5 OS”

References