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Up Front | Oct 2002

Anterior Ciliary Sclerotomy

Studies continue on this potential presbyopic treatment.

My colleagues and I performed a series of anterior ciliary sclerotomy operations in South Africa during August 2002 that restored accommodation in 100% of the patients. In this procedure, radially placed scleral incisions, beginning just outside the limbus, allow the passive expansion of the ciliary body. This expansion restores tension on the zonules, which allows the ciliary muscle to be more effective. Patients who are somewhat farsighted preoperatively seem to perform better with this procedure than those who are slightly nearsighted, which indicates that it may be beneficial to keep that muscle supple and strong.

If the incisions are allowed to heal, this accommodative increase disappears—a problem experienced with earlier procedures performed in 1996 and 1997. Changes to the operation include placing a barrier in the incisions to hold them open.

My colleagues and I designed a self-retaining, titanium tissue barrier that does not require permanent sutures for fixation. The barriers must remain in place indefinitely, and the sutures eventually biodegrade. These self-retaining barriers, named Hays Tissue Barriers, are manufactured by Duckworth and Kent Ltd. (Herts, England).

EARLY ATTEMPTS
The results of our initial studies in 1996 showed an increase in near vision for six of the eight patients, whom we treated with simple transconjunctival incisions and without tissue barriers. Conjunctival bleeding made this surgery difficult. Postoperatively, we were encouraged by the pa-tients' initial improvement in accommodation, but the effect generally vanished between 6 and 8 weeks. The incision sites healed so completely that they were either difficult or impossible to recognize by the 2-month follow-up visit.

TRIAL AND ERROR
To date, we have performed the procedure in 68 eyes in which we placed tissue barriers underneath the conjunctival flaps. Initially, we chose to use cellulose for the material and implanted these cellulose barriers in eight eyes in 1998. The eyes showed an average accommodative increase of 2.0 D at the first postoperative year, but the cellulose material was quite flimsy and difficult to manipulate.

We used titanium barriers in 60 of the 68 eyes on which we have performed this procedure. The initial titanium design produced less effect than the cellulose barriers—less than 1.0 D of improvement on average. Patients who performed significant amounts of near-point work experienced a better effect, a fact that reinforces the concept that the ciliary muscle must be exercised to work effectively.

We also noted that all the patients reported im-proved near vision and less dependence on reading glasses than surgeons generally expect from simple amplitude of accommodation measurements. There was not a strong parallel between the patients' subjective assessments and our accommodative amplitude measurements.

EXPERIMENTS IN BARRIER DESIGN
The most recent changes in barrier design address the difficulty of extrusion. Although intended to be self-retaining, a number of the early-model barriers surfaced out of the incisions. The barriers did not extrude through the conjunctiva but rather lay un-derneath it. As the barriers extruded, the effect of the operation vanished. We significantly widened the barriers and rounded the retaining pegs that previously were squared off. We feel the wider and rounder pegs will be much less likely to migrate through the sclera.

The initial results with these modified barriers are very encouraging. Many of the presbyopic patients on whom we operated recently were able to read in the 20/25 to 20/30 range at 30 cm within 1 day after undergoing the operation. So far, 100% of the pa-tients receiving the most recent barrier design report significantly improved near vision.

ONGOING RESEARCH
Where this procedure eventually fits into our re-fractive surgery armamentarium will depend on its long-term results. We will continue to follow these patients closely. Study sites are currently active in England, Venezuela, and South Africa, and plans are underway to begin a study in the US.

James C. Hays, MD, is in private practice at Omni Eye Services in Atlanta, Georgia. He holds no financial interest in any product discussed herein. Dr. Hays may be reached at (404) 351-1990; jhayseye@aol.com.
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