GoldLens Corneal Electrode
The GoldLens electrode is a low-noise, all-gold, bipolar specula corneal electrode. Designed specifically for focal ERG, the very low photoelectric artifact due to its all-gold construction also makes it ideal for full-field ERG.
Patterned after the Burian-Allen lens, but with significant improvements. These include modular design for better manufacturability and ease of repair; a round speculum for enhanced patient comfort and a wider range of fit; and gold electrodes to reduce noise from inter-electrode standing potential and photoelectric artifact. Made from the finest medical grade materials, the GoldLens will reward reasonable care with many years of service.
Extra large adult GoldLens
- Very low noise
- Large signal response
- All gold medical grade materials
- Very low photoelectric artifact
- More comfortable than competitive electrodes
- Available in adult, child and infant sizes
Using the GoldLens
Examine the entire GoldLens for damage. Look for cracks or scratches in the speculum and lens, and scratches, bends or breaks in the metal parts and lead wires which could compromise function or injure the eye. Disinfect before first use.
Clean and disinfect the GoldLens after each use.
- Ensure no conditions exist (e.g. scleral buckle, corneal disease) which would impede electrode insertion or otherwise contraindicate use of a contact lens electrode.
- Topically anesthetize the eye to be tested.
- Hold the GoldLens by its handle, with the concave side of the inner contact lens up.
- Add 2.5% methyl cellulose solution to the concave side of the inner contact lens until the lens appears about equally biconvex. A generous amount of methylcellulose solution will facilitate electrode contact over many minutes of testing, but do not use so much that it overflows into the convex side of the contact lens.
- Quickly invert the GoldLens so the drop of solution hangs upside down from the inner contact lens. Hold the lens with thumb and forefinger on either side (not top and bottom) of the handle.
- Instruct the patient to look down.
- Hold the lens above the eye with the handle pointing towards the outer can thus. Using the thumb of the other hand, retract the patientís upper lid and slide the speculum under the lid.
- Instruct the patient to look up.
- Holding the upper lid retracted with the speculum, retract the lower lid with the thumb and lower the speculum straight down onto the eye. It may be helpful to have the patient retract his own lower lid with the contra-lateral hand.
- Instruct the patient to look straight ahead.
- Examine the eye. Make sure the speculum lies securely under both lids. There should be no trapped eyelashes, no bubbles beneath the contact lens, and an even meniscus of solution should contact the inner electrode ring all around.
- Adjust the GoldLens handle to lie along the cheek pointing slightly temporally. Arrange the lead wires and tape them to the cheek to prevent pulling on the lens.
- In a seated patient with large eyes or flaccid lids, the lens may drift downwards over time. If necessary, this may be corrected by taping the speculum in place across itís upper (eyebrow) edge.
If all has gone well, your electrode should be in place similarly to that shown below:
GoldLens inserted into eye
- Remove all tape
- Instill a few drops of isotonic saline irrigating solution around the edge of the inner lens.
- Instruct the patient to look upward.
- Grasp the GoldLens handle and simultaneously retract the lower lid with the thumb.
- In one movement, push the GoldLens gently upward, to clear the lower lid, and lift it outward away from the eye.
- Use an isotonic saline irrigating solution to rinse the eye free of methylcellulose.
- Rinse the GoldLens thoroughly under warm running tap water or let it soak with handle out of water until it can be rinsed. Once dried on, methylcellulose is very difficult to remove.
- Rinse the GoldLens for 60 to 90 seconds under warm, gently flowing tap water to remove all methylcellulose solution from the contact lens.
- Fill an ultrasonic cleaner (such as the Branson B-3) about half full of tap water.
- Fill a 50ml beaker to a depth of about 1/2 inch with OíBrite or similar contact lens cleaning solution.
- Fill another 50ml beaker to about the same depth with distilled water.
- Sonicate the GoldLens for 10 to 20 seconds in cleaning solution.
- Sonicate the GoldLens for 20 to 30 seconds in distilled water.
- Rinse in fresh distilled water and air dry.
- Clean the GoldLens according to the above instructions. Like other instruments, it cannot be disinfected properly unless it is clean.
- Obtain a disinfecting solution consisting of a 70% or greater concentration (by volume) of ethanol in water. Place the GoldLens in an empty 50ml beaker and add enough disinfecting solution to cover the entire lens except the handle and lead wires.
- Place the beaker in an ultrasonic cleaner filled about half full of water (the cleaner should not contain enough water to float the beaker). Sonicate the GoldLens in the disinfecting solution for 5 to 10 seconds.
- Let the GoldLens soak in the disinfecting solution for 3 to 5 minutes.
- Rinse thoroughly in warm tape water.
- Sonicate 20 seconds in fresh distilled water.
- Rinse in distilled water and air dry.
Testing Lead Integrity
After long service, lead wires may fray or break internally, even though the lens may appear sound. Providing the electrode is completely dry, its lead integrity may be tested with an ohmmeter. Resistance should measure less than 5 ohms. Before testing the leads, clean ohmmeter prods carefully to avoid contaminating the lens and check ohmmeter calibration by touching prods together. Take care not to scratch the soft gold or plastic when contacting the GoldLens.
Corneal electrode lead
Measure between the black connector and the inner electrode spring, at edge of spring where it emerges from the handle.
Reference electrode lead
Measure between gray connector and outer electrode wire at a point near the rim of the speculum. The prod may scratch the soft gold, so take care when touching the prod to the metal parts of the GoldLens which may contact the patient.