A proprietary titanium caliper (Steiner Titanium Caliper, Stronger Medical Instruments) was designed to maintain accurate measurements and resist deforming of the tips even after numerous cycles of cleaning.
A proprietary titanium caliper (Steiner Titanium Caliper, Stronger Medical Instruments) was designed to maintain accurate measurements and resist deforming of the tips even after numerous cleaning cycles. Titanium also features a high weight-to-strength ratio and excellent corrosion resistance.
"All other calipers that ophthalmologists use have very soft and thin tips at their ends for measuring. When those ends become bent during use and cleaning, the precision of the instrument is compromised," said Michael Steiner, MD, an oculoplastic surgeon in Seattle. The calipers were developed in conjunction with him.
"I suggested making calipers from titanium so the instruments would maintain their accuracy and resist corrosion. I was frustrated that my calipers had a certain 'shelf life,' but with titanium we don't have that problem," he continued. "Plus, I think titanium is a more friendly type of metal for surgeons, because it cleans better than stainless steel."
Dr. Steiner said he uses the titanium calipers to make measurements on the eyelid tissues prior to incision. The matte finish on the titanium also picks up ink well, which also makes the calipers an effective marking tool, he explained. The calipers would be useful for many types of surgery, but calipers such as these usually are used for oculoplastic and strabismus surgeries, he added.
"It's very useful for pediatric ophthalmologists who operate on children who have strabismus," he said. "While extending or shortening the eye muscle tendons, these surgeons value both accuracy and consistency in their measurements."
A secondary purpose
Dr. Steiner said he particularly appreciates the ability to use his titanium caliper as a marking tool.
"That's really not possible with stainless steel, because the surface is too smooth and polished," he explained.
"Marking inks won't adhere to stainless steel, so other calipers don't make very effective markers," he said. "On the other hand, matte titanium works very well with marking inks."
The accuracy and longevity of the titanium calipers also eliminates a major concern ophthalmic surgeons may have had with similar steel instruments, Dr. Steiner said.
"The tips on these titanium calipers are quite strong. Steel calipers will deform, but unless you have something against which your assistant continually calibrates your instrument, you're likely to be unaware of this problem," he concluded.