Microincision cataract surgery speeds visual recovery with minimal edema

Surgically induced astigmatism was lower in a MICS study group despite enlargement of the IOL incision.

BOSTON — Coaxial microincision cataract surgery proved safer and more effective in a study group than conventional cataract surgery up to 1 month postop, a speaker said here.

Rosa Braga-Mele

Rosa Braga-Mele, MD, FRCSC, OSN Cataract Surgery Section Editor, presented study results comparing 1.8-mm microincision cataract surgery (MICS) with conventional 2.65-mm cataract surgery at the American Society of Cataract and Refractive Surgery meeting.

“Coaxial MICS optimized ... visual outcomes compared to conventional cataract surgery, even with the incision enlarged for IOL implantation,” Dr. Braga-Mele said. “We saw more rapid visual recovery, less initial postop inflammation, improved initial wound and corneal edema, and less surgically induced astigmatism.”

Investigators wanted to gauge the safety and efficacy of coaxial MICS with wound enlargement for IOL insertion, Dr. Braga-Mele said.

“I always wondered if smaller-incision surgery really was better,” she said. “There needs to be a bit of wound enlargement. My theory was that stretch and torque of the larger wound site during conventional cataract surgery led to greater impairment in wound integrity, healing and postoperative astigmatism.”

Study design and procedure

The prospective, randomized study included 20 patients who underwent coaxial MICS with a 1.8-mm incision and 20 patients who underwent standard coaxial cataract surgery with a 2.65-mm incision.

Inclusion criteria were less than 1 D of corneal astigmatism, no other corneal pathology and presence of nuclear cataracts. Exclusion criteria were previous ocular surgery and any significant astigmatism or systemic ocular disease, Dr. Braga-Mele said.

“Preoperatively, there really was no difference within the groups with respect to age, visual acuity, although the cataract grade was slightly higher and significant in the coaxial MICS group,” she said.

Investigators measured preoperative visual acuity, cataract grade, keratometry and corneal topography.

Dr. Braga-Mele performed all surgeries with the Stellaris phacoemulsification system (Bausch + Lomb). All patients received the Akreos AO IOL (Bausch + Lomb).

Patients in the MICS group had their incisions enlarged to 2.65 mm to allow IOL implantation.

Intraoperatively, a group of independent observers recorded procedure time, ultrasound time and energy, volume of balanced salt solution used, and incision size.

At 1 day, 1 week and 1 month after surgery, investigators assessed visual acuity, anterior chamber reaction, corneal and wound edema, keratometry, and corneal topography.

Outcomes and conclusions

At 1 day postop, the MICS group had statistically significantly less central corneal edema and wound edema than the conventional cataract surgery group.

The MICS group had statistically significantly better mean uncorrected visual acuity than the conventional cataract surgery group at 1 week (P = .0002) and 1 month (P = .0041).

“What was really interesting was that at both week 1 and month 1, the smaller-incision surgery, even with the wound enlargement to 2.65 mm ... showed that the surgically induced astigmatism was significantly less in the coaxial MICS group than in the conventional cataract surgery group,” Dr. Braga-Mele said.

In addition, markedly less balanced salt solution was used in the MICS cases than in the conventional cataract surgery group. The difference was statistically significant (P = .0006). Using less balanced salt solution minimized turbulence and trauma in the anterior chamber, Dr. Braga-Mele said.

“We saw more rapid visual recovery, less initial postop inflammation, improved initial wound and corneal edema, and less surgically induced astigmatism,” she said. “And it was nice to see that there was no additional time or ultrasound energy used during surgery.” – by Matt Hasson

• Rosa Braga-Mele, MD, FRCSC, can be reached at 245 Danforth Ave., Suite 200, Toronto, Ontario M4K 1N2, Canada; +1-416-462-0393; e-mail: rbragamele@rogers.com. Dr. Braga-Mele is a consultant for Bausch + Lomb but has no financial interest in its products.