February 2010

 

CATARACT / IOL

 

A closer look at SLIMCE


by Matt Young EyeWorld Contributing Editor

   
Dr. Lam performing SLIMCE Source: Dennis Lam, M.D.

A new manual cataract extraction technique may be able to help the developing world in ways that more conventional methods cannot. The technique, called SLIMCE (sutureless large-incision manual cataract extraction), has advantages over phacoemulsification, extracapsular cataract extraction (ECCE), and manual small-incision cataract surgery (SICS), according to Dennis S.C. Lam, M.D., F.R.C.Ophth., Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, the technique’s developer and advocate.

“Phacoemulsification involves high initial capital investment and consumable costs,” Dr. Lam noted in a study published in the October 2009 issue of Archives of Ophthalmology. “Manual ECCE involves a large 10– to 11– mm long surgical wound that increases the chance of potentially serious intraoperative complications, requires suturing, lengthens surgical time, and slows postoperative visual recovery. [And while SICS] may be sufficient for cataracts of mild to moderate density, hard large nuclei, which are common in populations with poor access to surgical services, may induce undue trauma to intraocular tissues.”

SLIMCE, meanwhile, can be utilized by less-experienced surgeons with basic equipment, requires no sutures, and excels in the realm of large and dense cataracts. “SLIMCE has the potential to serve as a safe and effective technique for cataract extraction to help reduce cataract blindness in developing countries,” Dr. Lam concluded.

The technique in action

A video of the SLIMCE technique is available for viewing at www.archophthalmol.com, and the full description can be found within the Archives study, “Endothelial Cell Loss and Surgically Induced Astigmatism After Sutureless Large-Incision Manual Cataract Extraction (SLIMCE).” Suffice it to say the technique involves a conjunctival limbal peritomy, sclerocorneal tunnel construction, side port incisions, capsular stain and capsulorrhexis, nucleus loosening, dislocation into the anterior chamber, and extraction, cortical material removal, and, of course, IOL insertion and closure. The scleral incision is 8 mm long, while the internal corneal wound opening is 9 to 10 mm in length. Dr. Lam analyzed 50 eyes of 50 consecutive patients who underwent SLIMCE, finding favorable results. While pre-op vision was finger counting or worse in 24% of patients and 20/80 to 20/200 in the majority (68%), all patients improved visual acuity after surgery, with 56% having a “good outcome” at 20/60 uncorrected visual acuity (UCVA) three months post-op. Some patients (44%) did have a “borderline outcome,” between 20/80 and 20/200 UCVA. None had vision worse than this post-op in the operated eye. Notably, after subjective refraction, all patients had a best-corrected visual acuity (BCVA) of at least 20/60. Further, 82% of patients had improvement of at least four Snellen lines. “No significant intraoperative complications such as posterior capsule rupture, vitreous loss, zonulolysis, or aphakia were encountered in these 50 patients,” Dr. Lam noted. “Self sealing wounds were achieved in all except 1 patient, who required 2 sutures to close the temporal main wound.”

Surgically induced astigmatism and endothelial cell loss also compared favorably to other techniques. “Safety of the surgery was reflected by the absence of significant intraoperative complications, a low SIA (0.69 D), and a low rate (3.9%) of endothelial cell loss, which compared favorably with endothelial cell loss reported for phacoemulsification, manual ECCE, and manual SICS, especially for large and dense cataracts,” Dr. Lam reported. There are remaining concerns about SLIMCE, such as post-op endophthalmitis, but the technique has taken this into account. “While a large main wound may theoretically increase the risk of postoperative endophthalmitis, the use of a long (4-mm) sclerocorneal tunnel may reduce such complications,” Dr. Lam noted. “In particular, 2 mm of the tunnel is located in the sclera, which greatly enhances the self-sealing property of the main wound. Moreover, the scleral incision was meticulously covered with conjunctiva at the end of the operation.”

In a separate study involving two local surgeons in rural China trained in the SLIMCE technique, Dr. Lam also reported that results were good. “Among 242 patients operated on by the 2 trained surgeons, 20/60 or better UCVA in the eye operated on was obtained in 83.4% and 20/60 or better BCVA in 95.7%,” Dr. Lam reported. “The mean post-op astigmatism did not differ between the eyes operated on and unoperated on. The study results confirm the effectiveness of skill transfer in this setting, with outcomes superior to those of most investigations in rural Asia.”

John D. Sheppard, M.D., professor of ophthalmology, microbiology, and immunology, Eastern Virginia Medical School, Norfolk, Va., upon hearing about SLIMCE, said that just like every surgical procedure, there’s going to be a risk-to-reward ratio. “If a person has a cataract yielding 20/400 vision and lives in an agrarian, unsophisticated society, the risk is justified with a less sophisticated technique,” he said. He acknowledged that it is difficult to bring phacoemulsification technology to many regions of the world, especially ones without a stable electricity supply. “Even using every cataract surgeon in the world does not allow us to catch up to the cataract burden,” Dr. Sheppard said. “Millions of people will die blind because they have poor access to the technology that is available. So clearly it doesn’t mean they have to have the world’s best modern phaco machine.”

Editors’ note: Dr. Lam has no financial interests related to this study. Dr. Sheppard has no financial interests related to his comments.

Contact information

Lam: dennislam_pub@cuhk.edu.hk
Sheppard: 757-622-2200, docshep@hotmail.com

A closer look at SLIMCE A closer look at SLIMCE
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