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Immediate Intraocular Pressure Response to Argon Laser Trabeculoplasty
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AMERICAN JOURNAL OF OPHTHALMOLOGY
envision their being achieved on a rou tine clinical basis. Perhaps we were overly pessimistic. With regard to the succinyldicholine response after strabismus surgery, we believed we were observing varying amounts of muscle paresis caused by surgical trauma. Our series was small and our interpretation may not have been correct. We hope Drs. Lingua and Azen will demonstrate that we have been too pes simistic. We look forward to learning the results of their studies. We will be especially interested in their observa tions of the succinyldicholine responses of patients with alternating circumduction before and after strabismus surgery. J O E L S. M I N D E L , JAMES B. EISENKRAFT,
M.D. M.D.
New York, New York
Immediate Intraocular Pressure Response to Argon Laser Trabeculoplasty EDITOR:
I read with interest the article, "Im mediate intraocular pressure response to argon laser trabeculoplasty" (Am. J. Ophthalmol. 95:279, March 1983), by R. N. Weinreb, J. Ruderman, R. Juster, and K. Zweig. We routinely administer 100 argon laser burns over 360 degrees of the trabecular meshwork. We have, however, always given patients 250 mg of acetazolamide immediately after the com pletion of the laser trabeculoplasty and hourly prednisolone drops for 24 hours. In those patients in whom posttreatment intraocular pressures have been measured, no increases have been re corded. S H O N A C . SULLIVAN, F.R.C.S. Cardiff, Wales
JULY, 1983
Reply EDITOR:
We are grateful to Dr. Sullivan for bringing this experience to our atten tion. The possibility that the administra tion of oral acetazolamide and topical prednisolone after laser trabeculoplasty may prevent the immediate postopera tive increase in intraocular pressure is reasonable, but requires further study. It is consistent with our hypothesis that this increase may be associated with dis ruption of the blood-aqueous barrier and the postoperative inflammatory re sponse. In our investigation, all patients were using maximal tolerated medical thera py. In most cases this included oral acetazolamide or another carbonic anhydrase inhibitor. Because we performed our laser treatments early in the morn ing, most patients had already adminis tered a dose of this medication. Wheth er an additional effect might have been obtained by administering yet another dose postoperatively remains to be de termined. Further, we recently treated a consec utive group of 18 patients with openangle glaucoma with topical 1% pred nisolone acetate every six hours for more than one week beginning 36 hours before laser trabeculoplasty in an at tempt to prevent the postoperative in crease in intraocular pressure. We found no statistically significant differ ence in the postoperative intraocular pressures of these patients and those of a similar group of patients who did not receive glucocorticoid. Nevertheless, it is possible that glucocorticoid, admin istered topically on a dosage schedule different than ours, may have a benefi cial effect. Because the frequency and magnitude of the postoperative increase in the in traocular pressure is reduced compared
AMERICAN JOURNAL OF OPHTHALMOLOGY
envision their being achieved on a rou tine clinical basis. Perhaps we were overly pessimistic. With regard to the succinyldicholine response after strabismus surgery, we believed we were observing varying amounts of muscle paresis caused by surgical trauma. Our series was small and our interpretation may not have been correct. We hope Drs. Lingua and Azen will demonstrate that we have been too pes simistic. We look forward to learning the results of their studies. We will be especially interested in their observa tions of the succinyldicholine responses of patients with alternating circumduction before and after strabismus surgery. J O E L S. M I N D E L , JAMES B. EISENKRAFT,
M.D. M.D.
New York, New York
Immediate Intraocular Pressure Response to Argon Laser Trabeculoplasty EDITOR:
I read with interest the article, "Im mediate intraocular pressure response to argon laser trabeculoplasty" (Am. J. Ophthalmol. 95:279, March 1983), by R. N. Weinreb, J. Ruderman, R. Juster, and K. Zweig. We routinely administer 100 argon laser burns over 360 degrees of the trabecular meshwork. We have, however, always given patients 250 mg of acetazolamide immediately after the com pletion of the laser trabeculoplasty and hourly prednisolone drops for 24 hours. In those patients in whom posttreatment intraocular pressures have been measured, no increases have been re corded. S H O N A C . SULLIVAN, F.R.C.S. Cardiff, Wales
JULY, 1983
Reply EDITOR:
We are grateful to Dr. Sullivan for bringing this experience to our atten tion. The possibility that the administra tion of oral acetazolamide and topical prednisolone after laser trabeculoplasty may prevent the immediate postopera tive increase in intraocular pressure is reasonable, but requires further study. It is consistent with our hypothesis that this increase may be associated with dis ruption of the blood-aqueous barrier and the postoperative inflammatory re sponse. In our investigation, all patients were using maximal tolerated medical thera py. In most cases this included oral acetazolamide or another carbonic anhydrase inhibitor. Because we performed our laser treatments early in the morn ing, most patients had already adminis tered a dose of this medication. Wheth er an additional effect might have been obtained by administering yet another dose postoperatively remains to be de termined. Further, we recently treated a consec utive group of 18 patients with openangle glaucoma with topical 1% pred nisolone acetate every six hours for more than one week beginning 36 hours before laser trabeculoplasty in an at tempt to prevent the postoperative in crease in intraocular pressure. We found no statistically significant differ ence in the postoperative intraocular pressures of these patients and those of a similar group of patients who did not receive glucocorticoid. Nevertheless, it is possible that glucocorticoid, admin istered topically on a dosage schedule different than ours, may have a benefi cial effect. Because the frequency and magnitude of the postoperative increase in the in traocular pressure is reduced compared