Glaucoma Care in Ghana
Glaucoma Care in Ghana
Christian Eye Ministry/International Aid
Donald L. Budenz, MD
Bascom Palmer Eye Institute
305-326-6384
dbudenz@med.miami.edu
Glaucoma is the most common cause of permanent visual loss in Africa. In West Africa, where the population is virtually 100% Black, open angle glaucoma is the most common type, although chronic narrow angle glaucoma from “creeping angle closure” also occurs, and is probably under-diagnosed. The prevalence of glaucoma in West Africa is not known, but we think it’s the highest in the world. Glaucoma has been shown to occur at an earlier age in Blacks and as many as 20% of the population over age 30 is probably at risk. We’ve seen congenital cases and juvenile open angle cases as well, so there are no age boundaries in this population. Glaucoma is also known to take a more rapid, aggressive form in this population.
Diagnosing glaucoma in Ghana can be difficult, primarily due to the lack of perimetry. Blacks are known to have larger cup:disc ratios physiologically, and up to 0.6 is considered normal. Many patients present with elevated IOP and large cups; there’s no reliable way to determine whether these patients have glaucoma or physiologic cupping with high IOP. It would be nice to have automated perimetry, but if it breaks or runs out of ink or paper, it would generally sit around for months or more before someone comes along with the supplies and know-how to fix it (like lasers, phaco machines, etc). It’s probably best to assume the worst and err on the side of treating in these situations.
Treatment of glaucoma is limited as well. Since medicines are costly, in short supply, need refrigeration in some cases, and patients live far away from sources, surgery remains the primary approach in this region. Since you’re unlikely to normalize IOP with laser trabeculoplasty, trabeculectomy remains the procedure of choice. If you are comfortable doing trabeculectomy surgery with antifibrotic agents, there is a great need for this in Ghana. However, if you’re not comfortable or do a fair number of these at home, there is the potential to do more harm than good. For those who are interested in doing some trabeculectomies, I’ve put together a description of the procedure that Drs. Egbert, Singh, and I have found to be most successful over the past 10 years.
Since the chance of failure in Blacks is so high without antifibrotic agents (mitomycin C or 5-fluorouracil), we always use these in our surgeries. We try to bring as much of each with us when we can and, when the mitomycin runs out, use 5-FU. The trouble with bringing mito is that it needs to be mixed in the pharmacy to a concentration of 0.4 or 0.5 mg/ml, then kept cold for 2 weeks, after which time it’s efficacy diminishes. If you can freeze it and manage to keep it frozen on the long journey to Africa, then it’s efficacious indefinitely. 5-FU comes in 50 mg/ml bottles and does not need to be refrigerated, so this is more practical. Whenever I use 5-FU intraoperatively at home, I save the remainder of the bottle, which technically is single use but can treat many patients in Africa if sterile technique is used to draw it up. I’ve never had any infections from re-using 5-FU straight from the bottle, even in Africa, so I think it’s OK to re-use. If you call me before your trip, I can usually mail you a bottle or 2 to take with you and use. It’s also helpful to ask your OR to save unopened 7-0 and 8-0 vicryl suture for you to take, particularly if you have a preference for conjunctival closure. I favor 8-0 vicryl on a vascular needle (Ethicon BV 130) but have used 7-0 and 8-0 vicryl on a cutting needle without problems. Try to bring what you’re used to, it’ll make it easier for you. Also, if you have access to your favorite conjunctival forceps or sclerostomy punch, bring it with you. The last time I went, the Kelly Descemet punch was out for repairs. Not the end of the world but it slowed me down (had to remember how they did it in the “old days,” easier for Dr. Egbert than myself).
Here’s the surgical procedure in some detail. After retrobulbar block and sterile prep and drape, I place a 7-0 or 8-0 vicryl traction suture through the peripheral cornea at 12:00 and rotate the eye inferiorly as much as possible by clamping the suture to the drape. Get this needle pass deep and long since it will be under quite a bit of traction for awhile and you don’t want it pulling through in the middle of an important step. I measure back 10 mm from the limbus with calipers and make a 6 – 8 mm conjunctival incision parallel to the limbus. If you try to cut down to sclera this far back, you’ll run into the superior rectus and oblique, which turns the case into a bloody mess (literally). I then dissect forward 4 mm or so between conjunctiva and Tenon’s layers until I’m sure I’m anterior to the muscle, then incise Tenon’s in a similar fashion, even extending past the Tenon’s incision 3 or 4 mm in each direction. I then cut the Tenon’s layer forward, toward the limbus at the outer extent of my incision, a maneuver called “Tenon’s release,” which helps with exposure later. Once I incise Tenon’s, I use it as a handle with the non-toothed tissue forceps rather than the conjunctiva to avoid tearing it. I always handle conjunctiva with non-toothed, serrated tissue forceps to keep from poking holes in the conjunctiva, which will leak in the early postoperative period causing a flat, failed bleb or flat, shallow chambers. Holding onto Tenon’s I dissect it off of the sclera using blunt Wescott scissors, spreading rather than cutting as much as possible to avoid creating a hole in the conjunctiva. I might emply a semi-sharp, flat instrument at this point to get the episcleral tissue away from the sclera, like a Green’s spoon or the cautery tip, or a cut-of Weckcell sponge (also in short supply there). Once I get to the limbus, I make sure I’m anterior to the Tenon’s insertion since cutting your trabeculectomy flap posterior to it will result in an anterior chamber entry that is over the ciliarly body. Once I’m sure I’ve dissected anteriorly to the conjunctival insertion, I inspect the dissection to make sure I haven’t created any buttonholes or tears along the way. This effects my choice of antifibrotic agent as I would generally either withhold them altogether or go with 5-FU if I thought I had a good chance of closing the defect.
Up until now, you’ve been able to do the case on your own but you’ll need some help from the scrub nurse at this point. I use a Weckcell sponge and gently sweep back the conjunctiva and Tenon’s layer to get optimal exposure, then ask the nurse to hold it there. They don’t have a microscope and don’t know how hard to push, so be patient with them, they really are good and eager to assist. I then cut a triangular trabeculectomy flap, over 50% deep, approximately 3 X 3 X 3 mm and dissect it anteriorly until I reach clear cornea, if possible. I do a larger flap in patients with previous cataract surgery because the sclera tends to be quite thin due to the extracap incision and what you lack in thickness you can make up for in size. If I’m sure I haven’t penetrated the anterior chamber, the nurses will give me the mitomycin C on a whole Weckcell sponge and I’ll place it on top of the trabeculectomy dissection and drape the conjunctiva over top of it for 3 to 5 minutes (longer exposure for patients with more risk factors for failure, like previous failed filter or previous cataract surgery). If I’m using 5 FU, I use it straight from the bottle that comes from the company (50 mg/ml) on a whole Weckcell sponge in the same spot as mito for 5 full minutes. I’ve heard recently that the folks at Moorfields are using larger pieces of sponge in hopes of getting larger, lower, more diffuse blebs. This is worth a try, too.
While I’m waiting, since there is nothing else to do, I’ll start my conjunctival closure by asking for the 8-0 vicryl on the BV needle or taking some vicryl from the traction suture and tie the beginning of my running suture, just the first throw to save a little time later. Once the time is up, I remove the sponge and rinse the area where the sponge was with 20 or 30 ml of whatever the irrigant of the day is (BSS is not necessary). I then place a paracentesis directly temporally with the Superblade and use this blade to enter the anterior chamber at the base of the trabeculectomy flap. You’ll need to sweep back the conj/Tenon’s again, positioning it so the nurse can hold it for you so both your hands are free. I use the Kelly Descemet punch (thanks to Dr. Kelly for supplying these and coming personally to use them!) to punch 1.5 – 2 holes posteriorly in the incision. The idea is to have the hole under the flap, not too anterior (or else they won’t filter) and not too much to the side (so they’ll filter out of the incision, sort of like a full-thickness procedure). Once the hole is made, the iris generally presents from it and you’ll need to do your iridectomy. It’s nice to have the nurse hold your trab flap up while you do this, but again, without the aid of the microscope, this is difficult. I try to straddle the sclerostomy with my DeWecker or Van Ness scissors, holding the flap open and grabbing the iris anteriorly, pulling out a bit, then closing the scissors. In this way, you’re using the scissors as a retractor as you’re getting set to cut the iris. I massage or irrigate the iris back into place and confirm that my iridectomy is patent and that all the iris tissue is out of the wound. Of course the chamber is shallow at this point and you’d like to move along and get the flap closed quickly. I use a single releasable suture to close the triangular flap, as taught to me by Kuldev Singh and he by Peter Egbert. It makes sense to use releasables since there is generally no way of performing laser suture lysis and you’d like to have a deep chamber at the end of the case and for the first week. You can use any of the techniques for releasables but I use this one because it’s easy and quick in my hands. Patientce Dadzie, the head nurse, is excellent at cutting or pulling these at the slit lamp at the appropriate time. I instruct her to pull the tail of the suture if the IOP is above 15 or cut the tail flush with the cornea if the IOP is controlled (15 mmHg or less) at 1 month postoperatively. We don’t want to leave the suture end exposed for longer since this could serve as an avenue for bleb infection (never seen it but afraid to try). I have attached a diagram of our technique for releasables. You start by placing a 10-0 nylon through the peripheral cornea, just behind your traction suture (which should be loose at this time for proper flap tension adjustment). This one can be superficial and should come out in line with the apex of the trabeculectomy flap. You then re-enter the peripheral cornea just at the limbus and pass the needle under the conjunctival insertion and up through the flap (by far the most difficult and scariest step of the entire procedure). You then re-enter the flap at its apex and take the needle down through the apex of the bed, just as you do when you’re using a non-releasable suture. Throw 3 throws in the suture and grab the nylon just anterior to the apex of the flap abd pull it tight, creating a loop. Adjust the tension on this triple throw until you are able to keep the chamber formed (checked by filling it with BSS through the paracentesis site) with a slow flow of fluid at the edges of the flap and a low/normal IOP. Then trim the needle end and the free end, leaving a tail on the free end to be pulled later if needed.
I then GENTLY pull the traction suture to get exposure for closure ONLY IF I NEED TO since this action could loosen your trabeculectomy flap closure. I close the conjunctiva and Tenon’s layers in a continuous running fashion, making sure to include conjunctiva AND Tenon’s in each bite. I specifically am looking for conj/anterior Tenon’s/posterior Tenon’s/posterior conj in each bite. This is faster than a double layer closure but you have to try to get Tenon’s in there to help fill any defects in the incision or needle tracks. After the closure, I fill the AC with BSS and watch for a bleb to form, make sure the chamber stays formed. Don’t use viscoelastic to fill the chamber, it will just go out the bleb and your chamber will go flat. If you can’t keep the chamber formed with BSS then your releasable is too loose. Remove the traction suture and give subconj injections of decadron and the antibiotic of the day.
Postoperatively, the nurses will want to give pred forte and antibiotic QID but insist on pred forte hourly for 2 weeks, the Q2 for a week, then a slow taper. The Wills group showed that frequent prolonged topical steroids improve the success of filtration surgery, they act at a different location in the scarring cascade than antifibrotic agents, so the more the better. I suggest a cycloplegic BID in phakic patients, they usually have one or another. With my 5-FU trabs, I routinely give daily subconj injections for as long as I’m there. I really think this improves the results in 5-FU cases. You want to give 5 mg, or 0.1 ml of the 50 mg.ml mixture that you’ve used intraoperatively. I’m not sure the staff is comfortable giving these, it’s really nice to give about 5 total injections starting on POD #4 (when the intraop stuff has started to wear off). It’s nice to let the center know you want to do some trabs in advance so they can schedule them EARLY in your stay so you can take care of the trabs yourself. The antibiotic can be stopped after a week, the cycloplegic probably after 3 weeks. There is some potential for shallowing after the suture is pulled but this is generally temporary. I resist the urge to do this in the first 5 to 7 days, preferring to massage the patient through this period of healing, similar to laser suture lysis. But if you have to pull it to get a bleb, then you have to. The chamber will generally reform even if shallow initially. Of course, a FLAT chamber (lens against cornea) requires urgent surgical repair with replacement of the flap suture.
I have included below the reference to a recent review of glaucoma care in West Africa, as well as some surgical results form Drs. Egbert and Singh, for additional reading (perhaps on the plane ride!). I hope this information has been helpful, please feel free to phone or e-mail me at the above number/address.
- Mermoud A, Salmon JF, Murray AND. Trabeculectomy with mitomycin C for refractory glaucoma in Blacks. Am J Ophthalmol 1993;116:72-78.
- Egbert PR, Williams AS, Singh KS, Dadzie P, Egbert TB. A prospective trial of intraoperative fluorouracil during trabeculectomy in a black population. Am J Ophthalmol 1993;116:612-616.
- Singh KS, Egbert PR, Byrd S, et al. Trabeculectomy with intraoperative 5-fluorouracil vs. mitomycin C. Am J Ophthalmol 1997;123:48-53.
- Singh KS, Byrd S, Egbert PR, Budenz D. Risk of hypotony after primary trabeculectomy with antifibrotic agents in a black West African population. J Glaucoma 1998;7:82-85.
- Egbert PR, Fiadoyor S, Budenz DL, Dadzie P. Trans-scleral diode laser cyclophotocoagulation as a primary surgical treatment for primary open angle glaucoma. Arch Ophthalmol, 2001;119:345-350.
- Budenz DL and Singh K. Glaucoma Care in West Africa. J Glaucoma, in press.
