Even though vitrectomies have been performed routinely for over 40 years, the effect that temperature has on the vitreous
and retinal surfaces during the procedure have not been measured before, noted Dr Reece Landers (University of North Carolina,
Chapel Hill, North Carolina, USA) when discussing his reasons for performing a recent study on this topic.1
"Therapeutic hypothermia is being used more and more throughout medicine these days, with many benefits, but also with some
possible bad side effects," he continued. "We determined that that we are in fact inducing hypothermia to the retina and vitreous
during vitrectomy with unknown (but probably minimal) side effects."
Effect of temperature
It is commonly known that therapeutic hypothermia will help to prevent ischaemic damage caused to tissues through a reduction
in the blood flow as a result of surgery and trauma. However, in vitrectomy the extent to which the retina is cooled is not
"Fortunately," Dr Landers added, "using room temperature infusion fluid during a victrectomy, which induces hypothermia in
the retina and vitreous (and probably other structures inside the eye, such as the lens) seems to have minimal side effects."
One of the main concerns and side effects of vitrectomy is cataract. "Many patients undergoing a vitrectomy develop a cataract
in their lens sooner than in their nonvitrectomized eye. We don't know the reason for this. It is just possible that it is
somehow related to the induced hypothermia... but this is still speculative," he explained.
To examine the temperature changes within the vitreous fluid and retinal surface, Dr Landers and colleagues measured the intraocular
temperature with a 23gauge (23G) thermoprobe before, during and after vitrectomy. "Prior to doing this research, we did not
know how much the temperature of the retina would drop during the study," Dr Landers said. "We did not know to what degree
the underlying choroidal circulation would keep the inner retina near its normal temperature during vitrectomy desipte the
eye being filled with relatively cool room temperature infusion fluid. It turned out that the temperature of the retina dropped
quite a bit during surgery." The changes in temperature that were recorded during the study were found to be statistically
significant in difference.
This prospective study, however, included only six patients and Dr Landers emphasized a need for further research to fully
examine what possible effects this change in temperature could have. "Ideally, a larger and longerterm study shoud be performed,
possibly even a controlled study that compares the effects of room temperature infusion fluid and warmer, possibly body temperature,
infusion fluid to see if the warmed fluid produces fewer cataracts," Dr Landers said. "We are continuing our measurements
to obtain larger data sets and we are also testing differing conditions, such as retinal detachments and other situations."
Dr Reece Landers, MD, is a vitreoretinal surgeon at the University of North Carolina, Chapel Hill, North Carolina, USA. He may be reached by Email:
Dr Landers has no financial interests in the subject matter.
1. M.B. Landers 3rd et al., Retina, 2012; 32(1):172–176.