The Role of Transscleral Laser Cyclotherapy in Glaucoma Therapy

Ciliodestructive procedures—procedures in which the ciliary processes are damaged in an attempt to reduce the production of aqueous humor and thereby lower intraocular pressure—have been viewed to some degree as the stepchildren of surgical glaucoma therapy, since this type of treatment was first introduced with penetrating diathermy and continued with cyclocryotherapy, ultrasound therapy of the ciliary body, and, more recently, transscleral laser cyclotherapy. This is because of the reported side-effects of this type of treatment, which include decreased visual acuity, phthisi, and sympathetic ophthalmia (Ophthalmology. 1992;99(7):1089–1094). A 2001 policy statement from the American Academy of Ophthalmology recommended that cyclophotocoagulation therapy be reserved for use in “advanced glaucoma in eyes with minimal visual potential” (Ophthalmology. 2001;108(11):2130–2138). Our own experience with transscleral cyclotherapy has led us to believe that this recommendation is much too narrow and results in the denial of effective therapy for many patients who could benefit from this treatment.

In 2004, we published a series of 21 eyes with visual acuity of 20/80 or better that had been treated with transscleral laser cyclotherapy and underwent an average follow up of 40 months. We reported that in the great majority of these eyes, their pretreatment visual acuity was preserved (Ophthalmology. 2004;111(7):1389–1392). A more recent publication by Ansari and Gandhewar has confirmed this finding (Eye. Published online ahead of print April 21, 2006). In 23 eyes of patients with primary open-angle glaucoma, the mean visual acuity improved from 6/22 to 6/19. Similarly, at the 2006 annual meeting of the American Glaucoma Society, we presented a series of 18 eyes that were post–penetrating keratoplasty with uncontrolled glaucoma. These eyes were treated with laser cyclotherapy and had a mean follow up of over 20 months. Sixteen of the 18 eyes had a visual acuity that was unchanged (12 eyes) or improved (4 eyes) (Poster presented at: 2006 annual meeting of the American Glaucoma Society; March 4, 2006; Charleston, SC).

Reconsidering the Role

It is reasonable to wonder why laser cyclotherapy is held in such low regard, while we are so enthusiastic about it. We believe that one primary reason is a sort of a self-fulfilling prophecy—that is, if this procedure is reserved for end-stage eyes that are unhealthy and have a very poor prognosis, then they will, in fact, do poorly. When used on eyes with less advanced disease, with better vision and a better prognosis, the results cited above suggest that they will do much better. We found that when we analyzed our own patients with neovascular glaucoma who had been treated with laser cyclotherapy, they did much worse as a group than did our other patients. Thus, if one treats only these types of patients, one will see poor results and believe that it is the result of an inferior treatment.

The use of laser cyclotherapy has been somewhat limited as well because of a fear of potential complications. Among these complications are decreased visual acuity, sympathetic ophthalmia in the fellow eye, and hypotony or phthisis.We have already addressed the visual acuity issue. As for sympathetic ophthalmia, there were several cases reported in the early days of laser cyclotherapy.^6,7 Most of these were treated with neodymium:YAG laser cyclotherapy rather than the diode laser therapy that is more commonly used today. In the more than 200 procedures that we have performed over the last decade, we have not had any cases of sympathetic ophthalmia. Similarly, in a retrospective series by Kramp and coworkers in Germany, no cases of sympathetic ophthalmia were seen in 250 procedures (Graefe’s Arch Clin Exp Ophthalmol. 2002;240(9):698–703). Hypotony is a concern and does occur, but in our experience, all of the eyes that developed hypotony or phthisis have been those with neovascular glaucoma. Other authors, however, have reported cases in other forms of glaucoma.

Because of this fear of hypotony, we have tended to be cautious in our treatment, and we accept that we will need to repeat the treatment in a significant number of our patients in order to obtain a satisfactory IOP. As we tell our patients, we can always add, but we can’t take away.

To its advantage, laser cyclotherapy is a very convenient procedure to perform. Contrary to the practices of some institutions, we perform this procedure either in the examining lane or, more commonly, in our minor procedure room. We do not take these patients to the operating room, with the exception of children and compromised adults who require general anesthesia. Most of the time, we perform the procedure under retrobulbar anesthesia. On rare occasions, however, where there are problems with anticoagulants and a risk of retrobulbar hemorrhage, we will infiltrate local anesthesia near the equator and treat half of the globe at a time.

Broader Indications

As noted earlier, we do not think that visual acuity is a useful criterion in deciding whether cyclotherapy is indicated. Cyclotherapy can be used for 20/20 eyes as well as for those with only light perception. There are certain conditions in which it seems to work particularly well. One of these is following penetrating keratoplasty, where we have achieved relatively good results without detrimentally affecting the transplant. In our experience, it has been superior to either shunt procedures or filtration surgery. It also has worked reasonably well in eyes that have drainage implants, where there is ultrasonic evidence of some drainage around the shunt plate, but the intraocular pressure is not adequately controlled. The reduced aqueous production from the laser cyclotherapy coupled with the continued outflow through the shunt is sufficient to get the IOP under satisfactory control in many patients. This is similar to the findings of a 2002 report by Semchyshym et al (Ophthalmology. 2002;109(6):1078–1084).

We also use this procedure on eyes with prior extensive disruption of the conjunctiva, such as eyes that have had scleral buckles with 360º conjunctival peritomies and eyes that have had several failed filters.

Finally, in spite of the poor results that we have obtained in this group, we still use it in neovascular patients, particularly for an eye with very limited vision potential where an invasive procedure is not warranted.

Summary

Transscleral laser cyclotherapy has a very definite role in the surgical management of glaucoma patients. It is noninvasive, so the risk of endophthalmitis is avoided. It is usually an office procedure and is convenient for both the doctor and the patient, and it has a beneficial effect on intraocular pressure control in a majority of patients, albeit with the need for multiple interventions in some patients. We believe that it should be more widely utilized.

References

Author Disclosure

The authors state that they have no financial relationship with the manufacturers of any of the laser cyclotherapy devices discussed in this article. Dr. Wilensky has received research support from Pfizer, Allergan, and Bausch & Lomb and is a member of the speakers bureaus for Pfizer, Allergan, and Alcon.