Fig. 34-20  Multiple (4–6) bisected LASIK sponges are saturated with mitomycin-C and placed posteriorly, adjacent and lateral to the superior rectus muscle. The conjunctival edge does not contact the sponges.

(A)

(B)

Fig. 34-22  (A) Lewicke anterior chamber maintainer (Visitec™) is connected to a 3-way stopcock and irrigating solution; its threaded metal end fits through an MVR-blade paracentesis. (B) Lewicke cannula obliquely situated in anterior chamber, allows for controlled intraoperative IOP.

Fig. 34-21  A single hemi-sponge with mitomycin-C is placed under the scleral flap, again avoiding the conjunctival edge.

postoperative weeks. Cycloplegics are sometimes used to reduce photophobia and prevent synechiae. Some surgeons though, to minimize any non-essential potential conjunctival irritant which might adversely affect the bleb, use neither mydriatic nor antibiotic, applying only steroid drops after surgery.

With remodeling over the first few months, low posterior diffuse blebs are less prone to complications, such as leakage, than are thin-walled, multicystic blebs. Several schemes for clinically classifying blebs have been proposed, which if widely adopted could significantly help standardize the surgical literature in distinguishing outcomes and problems with specific bleb morphology.66–68 One

system from Moorfields (Fig. 34-26A) has been developed for nonophthalmic graders assessing clinical postoperative photographs. A slightly simpler system, called the Indiana Bleb Appearance Grading System, is easily applied at the slit lamp for clinical notations (Fig. 34-26B).The value of consistent descriptions of blebs is relevant not only to research protocols, but to direct clinical care as well; for example, the not uncommon issue as to whether or not a contact lens is ‘safe to wear’ following trabeculectomy. Clinically the decision is based on the bleb morphology: common wisdom is that it can be worn more safely with low, diffuse blebs than with elevated thin blebs;69 but greater descriptive precision to correlate with the infection rates for specific types of blebs would be invaluable. And on the technological horizon, new advances with in-vivo

confocal imaging of filtration blebs may yield even greater information as to structural and functional correlations.70,70b,70c

Results

With the rapid evolution of surgical techniques and preferences over the past three decades, there are few rigorous long-term randomized

Fig. 34-23  A small sclerostomy is made, followed by iridectomy.

(A)

(B)

Fig. 34-24  (A) A 4-loop slip knot serves as an ‘adjustable’ suture for flap closure, tightened according to surgeon’s assessment of flow. (B) The flap is closed with multiple ‘adjustable’ sutures, which can be wiggled loose at the slit lamp postoperatively.

controlled trials comparing surgical versus medical treatment for primary open-angle glaucoma.71 Lower IOPs are usually achieved surgically, with better preservation of visual fields; acuity, however, is sometimes adversely affected by surgery due to cataract formation.2,72

Fig. 34-25  Slit-lamp transconjunctival adjustment of suture with blunt forceps.

(Courtesy of P Khaw.)

In the literature published before the wide use of antimetabolites with trabeculectomy, pressure levels of 21 mmHg or lower with or

without medications were achieved in the first 2 years in about 80% of eyes with primary open-angle glaucoma;20,22,73–78 sec-

ondary glaucomas generally responded less well. Success in aphakic eyes was usually less than 50%;79–82 young patients also had a lower success rate.45,83–85 After 4–5 years, however, success rates for

achieving IOPs between 16 and 21 mmHg diminish towards 50%, regardless of race.86,87

There is substantial cumulative evidence that use of an anti­ metabolite at the time of trabeculectomy surgery (either 5-FU or

mitomycin-C) provides lower long-term IOP control than not using such agents.88–90,90b However, the reported trials include

different types of glaucoma at variable risk for surgical failure; a variety of drug concentrations, application times, and delivery methods; and different lengths of clinical follow-up.Trends suggest

that in the first year following surgery, 5-FU and mitomycin results are comparable, with over 85% of eyes with ‘controlled’ IOPs;91,92

longer follow-up suggests a decay rate towards 65% at 5 years and towards 40% over 10 yrs.93,94 Despite long-term fall-off of surgical

control, both the lower IOPs achieved and the dampening of IOP fluctuation are felt to significantly reduce the rate of visual field deterioration.12,13 Serious complications such as bleb leaks, hypotonous maculopathy, and endophthalmitis are seen with both drugs,

and neither has rigorously demonstrated superiority in clinical efficacy or safety.88,88b

Some eyes undergoing trabeculectomy may develop a modest IOP elevation during the first several weeks after surgery. This pressure rise is transient and may not alter the success of the procedure. In one series73 evaluated before the advent of antimetabolites, releasable sutures or of laser suture lysis, up to 45% of eyes had pressures higher than 20 mmHg during the first month after surgery. At 1 year, however, less than 15% had pressures over 20 mmHg. It is important to realize that such a rise in IOP does not necessarily affect the ultimate outcome of the operation, and aqueous inhibitors should be avoided during the early post-operative period to maximize bleb dynamics. Although transient high post-operative IOP may be tolerated in some patients, it is not desirable. The ideal postoperative course begins with very low pressure (around 4–6 mmHg) and sees the pressure rise to