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Sutureless large-incision manual cataract procedure effective in rural China
The extracapsular technique, which uses a long, self-sealing tunnel incision, is proving to be a low-cost, reliable alternative to phaco.
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BEIJING — A sutureless, large-incision manual extraction procedure may be the best technique for cataract surgery in rural China, according to a surgeon speaking here.
Citing barriers such as cost and lack of infrastructure in rural villages in China, Dennis S.C. Lam, MD, FRCOphth, said there is a need to develop a low-cost, easily managed, reliable cataract surgical procedure that can be taught easily to local surgeons.
“We need to be able to provide quality cataract surgery in an affordable manner close to where people live,” Prof. Lam said here at the Asia-Pacific Association of Cataract and Refractive Surgeons meeting.
Phacoemulsification is not practical because of the expense, he said, and highly skilled surgeons are needed for small-incision procedures, which are difficult to teach.
“An ideal surgery would be sutureless, safe and effective with little astigmatism, low cost and would be easy to teach and learn.”
He said he believes that sutureless large-incision manual cataract extraction (SLIMCE), a technique that he developed, may be the solution to this problem.
Prof. Lam said conventional wisdom suggests that a large incision will induce astigmatism. To date, he said, he has not found that to be true in his results with the SLIMCE technique.
Technique
For the procedure Prof. Lam uses either peribulbar or retrobulbar anesthesia. No facial block is needed. He uses a temporal approach.
Prof. Lam said he fixates the globe with 0.12-mm forceps, then makes an 8-mm incision at a depth of 250 µm using either a diamond blade or a crescent knife to create a scleral tunnel.
“It’s about 2 mm on either side of the limbus, so the tunnel is about 4 mm in length,” he said. “For those with experience creating a small tunnel, it shouldn’t be difficult to create a large tunnel.”
He then instills two drops of trypan blue dye under air to facilitate capsulorrhexis in hard nuclei.
“You can use a cystotome or use forceps to complete your capsulorrhexis,” he said.
| Case 1 (top): Preop astigmatism (left) is 0.3 D at 140°; postop is 0.3 D at 120°. Case 2 (bottom): Preop astigmatism (left) is 2 D at 174°; postop is 1.6 D at 171°. | |
Prof. Lam said it is important to create a 6-mm capsulorrhexis, “otherwise you may have problems getting the nucleus into the anterior chamber.”
To move the lens from the capsular bag into the anterior chamber, Dr. Lam first uses a blunt iris repositor to mechanically separate the lens from the anterior capsular remnant, quadrant by quadrant. He then uses two Sinskey hooks, one placed at the center of the nucleus and the other at the equator of the nucleus at the end farthest from the incision. While pulling the nucleus toward the incision with the first hook, Prof. Lam elevates the nucleus at the equatorial region and moves it outside the capsular bag with the second hook. He then applies downward pressure on the nucleus near the incision with the near hook to “tumble” or invert the whole lens into the anterior chamber.
“We have tried many methods for removing the lens from the bag, and we find this method results in the least zonular stress,” Prof. Lam noted.
To remove the lens through the scleral tunnel, Prof. Lam inserts an anterior chamber maintainer to create hydrostatic pressure to push the lens toward the tunnel. The tunnel is partially opened by applying pressure near the scleral wound with Utrata forceps to push the lens through the tunnel. The nucleus is delivered with the help of a vectis, he said.
“The important part here is that if you do the tunnel right and position the vectis correctly, the nucleus will be delivered through the tunnel and without actually hitting the endothelium,” Prof. Lam said. “Once the nucleus is out safely, the remaining steps will be relatively simple, safe and easy.”
He removes residual nuclear fragments and cortical matter and polishes the anterior capsular remnant all over before inserting an IOL into the capsular bag.
“At the end of the day we can use cautery to close the conjunctiva without any sutures,” he said.
In Hong Kong, Prof. Lam said he performed this procedure on 100 consecutive eyes and found the endothelial cell loss to be less than 5%.
“The astigmatic change is less than 0.5 D,” he added.
For Your Information:
- Prof. Dennis S.C. Lam, MD, FRCOphth, can be reached at Hong Kong Eye Hospital, The Chinese University of Hong Kong, 3/F, 147K Argyle St., Kowloon, Hong Kong SAR, China; 852-2762-3157; fax: 852-2715-9490; e-mail: dennislam8@cuhk.edu.hk.
- David Mullin is the Managing Editor of Ocular Surgery News Europe/Asia-Pacific Edition.