REDUCING PAIN FOR PATIENTS UNDERGOING MICS

Using an ophthalmic viscosurgical device (OVD) that also contains an anaesthetic leads to reduced discomfort and pain for patients undergoing microincision cataract surgery (MICS), according to a study presented at the XXX Congress of the ESCRS. “Our study found that wound-assisted IOL insertion through a microincision wound was associated with only mild discomfort for the majority of patients. However, the addition of one per cent lidocaine in the viscoelastic reduced the amount of discomfort or pain that patients experience during MICS and this was statistically significant,†David Shahnazaryan MD told delegates.

Dr Shahnazaryan, an ophthalmologist at the Royal Victoria Eye and Ear Hospital, Dublin, Ireland, said that the goal of the study was to compare the intensity of pain during IOL insertion in patients undergoing MICS, and more specifically IOL insertion through a wound-assisted insertion technique, under topical anaesthesia using two different ocular viscoelastic agents. “Since most of the injectors that we currently use in our practices do not fit through a microincision we wanted to assess whether a wound-assisted technique might be associated with more pain,†he said.

Dr Shahnazaryan’s study included 100 eyes of 94 consecutive patients who underwent coaxial microincision cataract surgery through a 2.2mm incision. Patients were randomly assigned to one of two groups based on the type of viscoelastic used during the surgery: in group one, patients received intraoperative Visthesia (Carl Zeiss Meditec), comprising sodium hyaluronate and 1.0 per cent lidocaine, and group two patients received Amvisc (Bausch + Lomb) containing sodium hyaluronate and no anaesthetic.

After signing the informed consent form, all patients were familiarised with the visual analogue pain scale and asked to report their subjective pain scores at three different times during surgery. The first score was obtained five minutes before the surgery after administration of proxymetacaine topical anaesthetic, with all patients also receiving 1.0 per cent lidocaine gel immediately prior to the surgery. The second score was immediately obtained after wound-assisted IOL insertion and the final score was totalled at the end of the procedure. Dr Shahnazaryan noted that the mean pain score, which corresponded to less than mild discomfort in either group on administration of proxymetacaine, was not statistically different between the two groups and served as a control. In group one, however, the mean pain score was less for both the IOL insertion and for the total procedure compared with group two.

None of the patients in group one reported a pain score higher than 3.0 (mild pain), whereas 12 patients (24 per cent) in group two reported moderate pain greater than 4.0. The mean total pain score was less than 3.0, corresponding to mild discomfort in each group, but it was statistically significantly less in group one, said Dr Shahnazaryan. The mean duration of surgery was similar for both groups and statistical analysis showed no correlation between the duration of surgery and the pain score in either group. Dr Shahnazaryan said that the pain difference experienced between the two groups was probably related to the woundassisted technique. “This can be associated with stretching of the wound in microincision surgery and therefore more pain and discomfort for the patient. However, the use of viscoelastic with anaesthetic achieves adequate pain control and comfortable surgery,†he concluded.