Dear Editor

We read with interest the article by Joussen et al. on the long term results of retinectomy for the treatment of intractable glaucoma.[1] We congratulate the authors for studying this innovative method for the management of refractory glaucoma with a long follow-up of five years.

The high incidence of complications in the study however has aroused our concerns as only 15.9% of patients completed the study uneventfully. Further vitreoretinal surgeries were required in 47.7% due to retinal complications. Moreover, the incidence of hypotony, phthisis and enucleation was 25%, 20% and 16% respectively and these figures are higher compared with other treatment modalities like glaucoma implants and cyclodiode. We have previously studied the use of Ahmed valve implant for complicated glaucoma, and hypotony, phthisis and enucleation occurred in 10.8%, 3.1% and 1.5% respectively.[2] A recent study on the management of refractory glaucoma by cyclodiode similarly found a lower rate of hypotony and phthisis of 9.5% and 5.3% respectively.[3] The high complication rates in the study by Joussen et al. may be due to the negative case selection with high incidence of aphakic (30%) and infantile and juvenile glaucoma (7%). Further controlled study comparing retinectomy with other treatment modalities may therefore be warranted.

In this evidence-based era, emphasis should be placed on outcomes which are "patient-oriented evidence that matters" (POEMs).[4] It was stated by the authors that the main intentions of the surgery were to relieve pain and to preserve the eye without discomfort. Unfortunately, these POEMs were not included in the final outcome measures. Instead, success was determined by "disease-oriented evidences" (DOEs) like intraocular pressure and retinal attachment which are surrogate outcomes.[5] These DOEs may not correlate well with the patients' symptoms and it would be valuable if the authors can include the level of pain and discomfort as other outcome measures for the study.

References

1. Joussen AM, Walter P, Jonescu-Cuypers CP, et al. Retinectomy for treatment of intractable glaucoma: long term results. Br J Ophthalmol 2003;87:1094-1103.

2. Lai JS, Poon AS, Chua JK, et al. Efficacy and safety of the Ahmed glaucoma valve implant in Chinese eyes with complicated glaucoma. Br J Ophthalmol 2000;84:718-21.

3. Murphy CC, Burnett CA, Spry PG, et al. A two centre study of the dose- response relation for transscleral diode laser cyclophotocoagulation in refractory glaucoma. Br J Ophthalmol 2003;87:1252-7.

4. Shaughnessy AF, Slawson DC, Bennett JH. Becoming an information master: a guidebook to the medical information jungle. J Fam Pract 1994;39:489-99.

5. Temple R. Are surrogate markers adequate to assess cardiovascular disease drugs? JAMA 1999;282:790-5.