DIY: Optokinetic Drums

Optokinetic drums are used to diagnose tracking problems with patients' eyes. The drum is used to elicit and evaluate nystagmus (involuntary rapid movement of the eyeball) in the patient. When the drum is rotated, the patient focuses on it, and the evaluator watches for nystagmus. In a normal individual, the eyes will track smoothly in the direction the drum is turning and back, but in patients with certain disorders, the eyes will skip or dart. An individual can be born with nystagmus or develop it later on from various causes, including certain medications, alcohol intoxication or substance abuse.

Things You'll Need

• Safety goggles
• Two wooden discs, 8 1/4 to 8 1/2 inches in diameter
• Black and white paint
• Paintbrush
• Pencil
• Level with straight edge
• Painter's tape
• Tape measure
• Hollow wooden cylinder, 12 inches high, 8 inches in diameter
• Wood putty
• Sandpaper
• Rolling pin handle with assembly (should include handle, dowel, and ball bearing kit)
• Wood screws
• Power screw driver/drill
• Wing nut

Show More

Instructions

Paint the Drum

• 1

  Paint the two wooden discs black. Apply two or more coats if necessary.

• 2

  This measurement should equal the width of your painter's tape.

  Measure every 1 inch along the top circumference of the cylinder with a tape measure, and mark with a pencil.

• 3

  The surface is level when the bubble is centered between the two lines.

  Using a level to make sure the line is straight, make marks parallel to the original marks along the bottom of the cylinder. Using the straight edge of the level, draw lines in pencil from mark to mark, making parallel lines all around the cylinder.

• 4

  Using painter's tape will give you crisp, clean lines.

  Lay painter's tape along every other line, stretching from end to end of the cylinder. You should now have a cylinder with alternating vertical stripes of bare wood and painter's tape.

• 5

  Paint all the exposed wood areas with white paint. Allow paint to dry completely. Apply two or more coats if necessary.

• 6

  Remove painter's tape, and reapply new tape over the white stripes. You should again have alternating stripes of bare wood and painter's tape.

• 7

  Paint all the exposed wood with black paint. Allow paint to dry completely before removing tape.

Assembling the Drum

• 8

  Screw the top disc onto one end of the wooden cylinder, using the power drill and wood screws. Fill any gap left by the screw with wood putty, allow to dry completely and paint over with black paint.

• 9

  Slide the dowel part of the handle assembly through the handle. Add a bit of wood glue to the end to hold the dowel in place, if necessary.

• 10

  Drill a hole in the remaining disc just big enough to pass the handle dowel through it. Sand the hole so the dowel will rotate within it smoothly.

• 11

  Slide the dowel through the hole in the disc, then install the remaining handle assembly, most likely including a ball bearing and separators. Hold assembly in place with a wing nut, if necessary. Test to make sure the disc rotates smoothly around the handle assembly.

• 12

  With the handle protruding out the bottom, screw the bottom disc onto the wooden cylinder. Again, fill any gaps with wood putty and paint black.

• 13

  Spin the drum smoothly for the most accurate testing.

  Hold the handle with one hand and spin the drum with the other. Check for smooth, continuous movement of the drum. Make adjustments as necessary. Your optokinetic drum is now ready for testing.