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Apraclonidine and Argon Laser Trabeculoplasty
Apraclonidine and Argon Laser Trabeculoplasty Paul C. H o l m w o o d , M.D., R. D o n a l d C h a s e , D . O . , Theodore Krupin, M . D . , Lisa F. Rosenberg, M.D., Jon M. Ruderman, M . D . , Barbara A. Tallman, B.S., D a v i d E. Brodstein, M . D . , Hersh Chopra, M . D . , and Mordechai G o l d e n f e l d , M . D .
Sixty patients with medically uncontrolled open-angle glaucoma (intraocular pressure greater than 21 mm Hg) were randomly assigned to one of two treatment regimens with apraclonidine before undergoing 360-degreé argon laser trabeculoplasty. One drop of apraclonidine 1% was instilled one hour before and immediately after laser treatment in 30 eyes or apraclonidine was delivered only after trabeculoplasty in 30 eyes. Intraocular pressure before laser treatment, number of antiglaucoma medications, and the laser treatment settings were comparable between the two groups. The mean and percent change in intraocular pressures were similar in both treatment groups one and two hours after trabeculoplasty. One drop of apraclonidine 1% instilled immediately after argon laser trabeculoplasty prevented intraocular pressure increase one hour and two hours postoperatively as effectively as its instillation both one hour before and immediately after laser treatment.
O N E OF THE MOST important complications of
argon laser trabeculoplasty is postoperative in crease in intraocular pressure. Even a brief episode of intraocular pressure increase may further compromise a damaged optic nerve. Increased intraocular pressure after argon laser trabeculoplasty can result in visual field deteri oration or loss of central vision.1*2 In 1987, Robin and associates 8 found that topical pretreatment with the alpha-adrenergic
Accepted for publication April 29, 1992. From the Glaucoma Service, Department of Ophthal mology, Northwestern University Medical School, Chi cago, Illinois. This study was supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York. Reprint requests to Theodore Krupin, M.D., Depart ment of Ophthalmology, Ward Building 2-186, 303 E. Chicago Ave., Chicago, IL 60611.
agonist, apraclonidine hydrochloride, prevent ed the acute intraocular pressure increase after 360-degree argon laser trabeculoplasty. Apra clonidine 1% was instilled both one hour be fore and immediately after the laser procedure in this and other clinical studies using the drug. 4 7 The decision to use this dosing regimen has been arbitrary. In our study in which pa tients were randomly assigned to treatment, we found that instillation of one drop of apracloni dine immediately after argon laser trabeculo plasty is as effective as the previously described pre- and posttreatment regimen in preventing an early postoperative increase in intraocular pressure.
Patients and Methods Patients who had primary open-angle glauco ma, defined by optic disk cupping and visual field loss, and a pretreatment intraocular pres sure greater than 21 mm Hg on maximally tolerated medical therapy, were included for study. Patients who h a d undergone previous intraocular surgical procedures or laser treat ment, patients who had secondary open-angle glaucoma (pigmentary, exfoliative, or uveitic, for example), and patients who were younger than 40 years were excluded. Treatment with antiglaucoma medications was maintained be fore the laser treatment. Informed consent was obtained for participation in the study and for the argon laser trabeculoplasty. Preoperative applanation intraocular pres sure was measured. One of the following two apraclonidine open-label treatment regimens was determined from a random table chart: instillation of one drop of the drug one hour preoperatively and immediately postoperatively or instillation of one drop of the drug only immediately after the laser procedure. Intraoc ular pressure was measured one and two hours after treatment by an observer who was masked
©AMERICAN JOURNAL OF OPHTHALMOLOGY 114:19-22, JULY, 1992
19
July, 1992
AMERICAN JOURNAL OF OPHTHALMOLOGY
20
to the random assignment to treatment with apraclonidine. Argon laser trabeculoplasty was performed using an argon laser (model 900, Coherent, Palo Alto, California), anesthesia achieved with topical proparacaine hydrochloride 0.5%, and an antireflective coated three-mirror Goldmann goniolens. Laser settings included a 50-μπι spot, a 0.1-second duration, and a power set ting between 400 and 1,200 mW that was suffi cient to induce a visible blanching with occa sional bubble formation. Laser treatment (80 to 85 applications) was delivered to the anterior trabecular meshwork for 360 degrees in both treatment groups. Only one eye of a patient was included in our study. 8 Results were determined as the mean ± standard error of the mean. Statistical analysis used nonparametric techniques for two popula tion distributions (Mann-Whitney test) and for matched samples (Wilcoxon test), and the Fish er's exact test (one-tailed) to compute probabil ities.
Results Sixty patients were randomly assigned to treatment (30 patients to each treatment group). There were no statistical differences between preoperative intraocular pressure (z = 0.1, P = .8) and the number of antiglaucoma medications (z = 0.3, P = .7) between the two groups of patients (22.9 ± 0 . 9 mm Hg and 2.4 ± 0.2 medications for patients treated with apra clonidine before and after laser treatment; 22.6 ± 0.6 mm Hg and 2.4 ± 0.2 medications for patients treated with apraclonidine only after laser treatment). Total amount of applied ener gy and number of laser applications were also similar between the two groups of patients (6.6 ± 0.2 and 6.3 ± 0.2 mj of energy, respectively [z = 1.3, P = .2]; 82.9 ± 1.6 and 81.6 ± 1.9 laser applications, respectively [z = 1.5, P = .1]). Intraocular pressure was significantly re duced in both treatment groups one hour and two hours after argon laser trabeculoplasty (Ta ble 1). Intraocular pressure was similar be tween the two groups at these postoperative time intervals (P = .7) as well. One hour after laser treatment, intraocular pressure was equal to or less than preoperative values in 23 of 30 eyes (76%) treated with apraclonidine both before and after the procedure and in 25 of 30 eyes (83%) treated only after laser treatment (P
TABLE 1 INTRAOCULAR PRESSURE AFTER APRACLONIDINE INSTILLATION INTRAOCULAR PRESSURE (MEAN±SEM)·
Preoperative One hour postoperative Two hours postoperative
BEFORE AND
ONLY AFTER
AFTER LASER TRABECULOPLASTY
LASER TRABECULOPLASTY
22.6±0.9 19.5±1.0t 17.5±0.8t
22.6±0.6 18.9±1.0t 17.1 ±0.9*
»SEM indicates standard error of the mean. tSignificant decrease compared to preoperative intraocular pressure, P < .01.
= .4). A similar (P = .5) magnitude of intraocu lar pressure change was present two hours after laser treatment. Both treatment groups had the same (P = .6) number of eyes demonstrating an intraocular pressure increase 1 to 5 mm Hg higher than preoperative levels (Table 2). Intra ocular pressure increase 6 to 10 mm Hg higher than the preoperative level developed in two eyes one hour and in one eye two hours postoperatively in the treatment group that was treat ed with apraclonidine both before and after laser treatment. This magnitude of pressure increase was not observed in the group of patients treated with apraclonidine only after laser treatment. However, this difference was not significant (P = .2).
Discussion Technical aspects of argon laser treatment to the trabecular meshwork may account for tran sient postoperative increases in intraocular pressure. A greater frequency of intraocular pressure increase has been associated with treatment to the posterior trabecular meshwork and 360-degree treatment, 9 the amount of ener gy delivered per laser pulse, 10 and the total energy delivered during the treatment ses sion. 1 However, marked intraocular pressure increases may still develop with anterior tra becular laser burn placement and after 180degree trabecular meshwork treatment. Laser treatment settings in our study were similar in the two apraclonidine treatment groups. Ad ditionally, the treating ophthalmologist was masked to each patient's treatment regimen. The development of postoperative increases in
Vol. 114, No. 1
Apraclonidine and Argon Laser Trabeculoplasty
TABLE 2 POSTOPERATIVE CHANGE IN INTRAOCULAR PRESSURE AFTER APRACLONIDINE INSTILLATION BEFORE AND
ONLY AFTER
AFTER LASER
LASER
TRABECULOPLASTY TRABECULOPLASTY POSTOPERATIVE
(N=30)
(N=30)
NO. (%)
NO. (%)
23 (76)
25 (83)
5(17)
5(17)
INTERVAL OF INTRAOCULAR PRESSURE CHANGE
One hour postoperatively Intraocular pressure spreoperative level Intraocular pressure increase of 1 to 5mmHg Intraocular pressure increase of 6 to 10 mm Hg Two hours postoperatively Intraocular pressure £ preoperative level Intraocular pressure increase of 1 to 5 mm Hg Intraocular pressure increase of 6 to 10 mm Hg
2 (7)
—
27 (90)
28 (93)
2 (7)
2 (7)
1 (3)
—
intraocular pressure after laser trabeculoplasty were highly correlated between the two eyes of patients with primary open-angle glaucoma. 8 For this reason, only one eye of a patient was included in our study. Medical treatment of the postoperative in crease in intraocular pressure can be ineffec tive, with some patients requiring filtration surgical procedures. Preoperative treatment with the long-term administration of the cur rently available topical antiglaucoma medica tions, systemic hyperosmotic agents, systemic carbonic anhydrase inhibitors, or topical corticosteroids, has not effectively inhibited the intraocular pressure after laser treatment. 1113 Although treatment with topical pilocarpine reduces trabeculoplasty-induced intraocular pressure increase, 6,14 many patients undergoing glaucoma laser procedures are already being treated with this and other antiglaucoma medi cations. This may account for the inability of these drugs to have a major effect on reducing laser-induced intraocular pressure increases. Our results confirmed previous observations on the efficacy of topical apraclonidine 1% in preventing acute increases in intraocular pres sure after 360-degree argon laser trabeculo plasty (Table 1). Apraclonidine instillation im mediately after laser trabeculoplasty in eyes with open-angle glaucoma is equally effective
21
as apraclonidine instillation both one hour be fore and immediately after the procedure in preventing early (one- and two-hour) postoper ative laser-induced increases in intraocular pressure. Both treatment regimens reduced the frequency of an acute increase in intraocular pressure, which is frequently observed without apraclonidine pretreatment after argon laser trabeculoplasty; 20% to 40% of eyes with openangle glaucoma have a postoperative increase greater than 10 mm Hg. 11115 Apraclonidine treatment markedly reduces the frequency and magnitude of postoperative increase in intraoc ular pressure after 360-degree argon laser tra beculoplasty (Table 1). Additionally, intraocu lar pressure is significantly reduced one hour and two hours postoperatively (Table 2) when apraclonidine is instilled after laser trabeculo plasty. Although postoperative intraocular pressure increase greater than 10 mm Hg was not measured in our study, this complication develops in up to 8% of eyes treated with apraclonidine both before and after laser tra beculoplasty.3 " 7 Therefore, postoperative intra ocular pressure measurements are required to detect and treat this complication. Our study did not evaluate the effectiveness of a one-drop instillation of apraclonidine be fore laser trabeculoplasty. However, in a recent study one drop of the alpha-adrenergic agonist, brimonidine tartrate, given either before or after argon laser trabeculoplasty was as effec tive in preventing postlaser intraocular pres sure increase as one-drop instillation both before and after laser treatment. 16 Possible benefits from instillation of just one drop of apraclonidine include reduction in the poten tial for medication-induced side effects, reduc tion in cost, and convenience of drug delivery. Treatment with apraclonidine before and af ter laser iridotomy 17 and posterior capsulotomy18 prevented postoperative increases in intra ocular pressure. Our results did not confirm the effectiveness of a single instillation of apraclo nidine for these anterior segment laser proce dures.
References 1. Weinreb, R. N., Ruderman, J., Juster, R., and Zweig, K.: Immediate intraocular pressure response to argon laser trabeculoplasty. Am. J. Ophthalmol. 95:279, 1983. 2. Thomas, J. V., Simmons, R. J., and Belcher,
22
AMERICAN JOURNAL OF OPHTHALMOLOGY
C. D.: Argon laser trabeculoplasty in the presurgical glaucoma patient. Ophthalmology 89:187, 1982. 3. Robin, A. L., Pollack, I. P., House, B., and Enger, C : Effects of ALO 2145 on intraocular pres sure following argon laser trabeculoplasty. Arch. Ophthalmol. 105:646, 1987. 4. Brown, R. H., Stewart, R. H., Lynch, M. G., Crandall, A. S., Mandell, A. I., Wilensky, J. T., Schwartz, A. I., Gaasterland, D. E., DeFaller, J. M., and Higginbotham, E. J.: ALO 2145 reduces the in traocular pressure elevation after anterior segment laser surgery. Ophthalmology 95:378, 1988. 5. Rao, B. S., and Badrinath, S. S.: Efficacy and safety of apraclonidine in patients undergoing ante rior segment laser surgery. Br. J. Ophthalmol. 73:884, 1989. 6. Robin, A. L.: Argon laser trabeculoplasty medi cal therapy to prevent the intraocular pressure rise associated with argon laser trabeculoplasty. Oph thalmic Surg. 22:31, 1991. 7. Allf, B. E., and Shields, M. B.: Early intraocular pressure response to laser trabeculoplasty 180 de grees without apraclonidine versus 360 degrees with apraclonidine. Ophthalmic Surg. 22:539, 1991. 8. Bishop, K. I., Krupin, T., Feitl, M. E., Adelson, A., and Werner, E. B.: Bilateral argon laser trabeculo plasty in primary open-angle glaucoma. Am. J. Oph thalmol. 107:591, 1989. 9. Schwartz, L. W., Spaeth, G. L., Traverse C , and Greenidge, K. C : Variation of techniques on the results of argon laser trabeculoplasty. Ophthalmolo gy 90:781, 1983. 10. Rouhiainen, H. J., Teräsvirta, M. E., and Tuovinen, E. J.: Laser power and postoperative intraocu lar pressure increase in argon laser trabeculoplasty. Arch. Ophthalmol. 105:1352, 1987. 11. Hoskins, H. D., Jr., Hetherington, J., Jr.,
July, 1992
Minckler, D. S., Lieberman, M. F., and Shaffer, R. N.: Complications of laser trabeculoplasty. Oph thalmology 90:796, 1983. 12. Cyrlin, M. N., and Beckman, H.: Low-dose oral glycerin for prevention of post-laser IOP elevation. ARVO abstracts. Supplement to Invest. Ophthalmol. Vis. Sci. Philadelphia, J. B. Lippincott, 1987, p. 272. 13. Ruderman, J. M., Zweig, K. O., Wilensky, J. T., and Weinreb, R. N.: Effects of corticosteroid pretreat ment on argon laser trabeculoplasty. Am. J. Ophthal mol. 96:84, 1983. 14. Ofner, S., Samples, J. R., and Van Buskirk, E. M.: Pilocarpine and the increase in intraocular pressure after trabeculoplasty. Am. J. Ophthalmol. 97:647, 1984. 15. Krupin, T., Kolker, A. E., Kass, M. A., and Becker, B.: Intraocular pressure the day of argon laser trabeculoplasty in primary open-angle glaucoma. Ophthalmology 91:361, 1984. 16. Spaeth, G. L„ David, R., Clevenger, C. E., Perell, H. F., and Siegel, L. I.: The effects of brimonidine tartrate on the incidence of intraocular pressure (IOP) spikes following argon laser trabeculoplasty (ALT). ARVO abstracts. Supplement to Invest. Oph thalmol. Vis. Sci. Philadelphia, J. B. Lippincott, 1992,. p. 1159. 17. Robin, A. L., Pollack, I. P., and deFaller, J. M.: Effects of topical ALO 2145 (p-aminoclonidine hydrochloride) on the acute intraocular pressure rise after argon laser iridotomy. Arch. Ophthalmol. 105:1208, 1987. 18. Pollack, I. P., Brown, R. H., Crandall, A. S., Robin, A. L., Stewart, R. H., and White, G. L.: Pre vention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topi cal 1% apraclonidine. Arch. Ophthalmol. 106:754, 1988.
Sixty patients with medically uncontrolled open-angle glaucoma (intraocular pressure greater than 21 mm Hg) were randomly assigned to one of two treatment regimens with apraclonidine before undergoing 360-degreé argon laser trabeculoplasty. One drop of apraclonidine 1% was instilled one hour before and immediately after laser treatment in 30 eyes or apraclonidine was delivered only after trabeculoplasty in 30 eyes. Intraocular pressure before laser treatment, number of antiglaucoma medications, and the laser treatment settings were comparable between the two groups. The mean and percent change in intraocular pressures were similar in both treatment groups one and two hours after trabeculoplasty. One drop of apraclonidine 1% instilled immediately after argon laser trabeculoplasty prevented intraocular pressure increase one hour and two hours postoperatively as effectively as its instillation both one hour before and immediately after laser treatment.
O N E OF THE MOST important complications of
argon laser trabeculoplasty is postoperative in crease in intraocular pressure. Even a brief episode of intraocular pressure increase may further compromise a damaged optic nerve. Increased intraocular pressure after argon laser trabeculoplasty can result in visual field deteri oration or loss of central vision.1*2 In 1987, Robin and associates 8 found that topical pretreatment with the alpha-adrenergic
Accepted for publication April 29, 1992. From the Glaucoma Service, Department of Ophthal mology, Northwestern University Medical School, Chi cago, Illinois. This study was supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York. Reprint requests to Theodore Krupin, M.D., Depart ment of Ophthalmology, Ward Building 2-186, 303 E. Chicago Ave., Chicago, IL 60611.
agonist, apraclonidine hydrochloride, prevent ed the acute intraocular pressure increase after 360-degree argon laser trabeculoplasty. Apra clonidine 1% was instilled both one hour be fore and immediately after the laser procedure in this and other clinical studies using the drug. 4 7 The decision to use this dosing regimen has been arbitrary. In our study in which pa tients were randomly assigned to treatment, we found that instillation of one drop of apracloni dine immediately after argon laser trabeculo plasty is as effective as the previously described pre- and posttreatment regimen in preventing an early postoperative increase in intraocular pressure.
Patients and Methods Patients who had primary open-angle glauco ma, defined by optic disk cupping and visual field loss, and a pretreatment intraocular pres sure greater than 21 mm Hg on maximally tolerated medical therapy, were included for study. Patients who h a d undergone previous intraocular surgical procedures or laser treat ment, patients who had secondary open-angle glaucoma (pigmentary, exfoliative, or uveitic, for example), and patients who were younger than 40 years were excluded. Treatment with antiglaucoma medications was maintained be fore the laser treatment. Informed consent was obtained for participation in the study and for the argon laser trabeculoplasty. Preoperative applanation intraocular pres sure was measured. One of the following two apraclonidine open-label treatment regimens was determined from a random table chart: instillation of one drop of the drug one hour preoperatively and immediately postoperatively or instillation of one drop of the drug only immediately after the laser procedure. Intraoc ular pressure was measured one and two hours after treatment by an observer who was masked
©AMERICAN JOURNAL OF OPHTHALMOLOGY 114:19-22, JULY, 1992
19
July, 1992
AMERICAN JOURNAL OF OPHTHALMOLOGY
20
to the random assignment to treatment with apraclonidine. Argon laser trabeculoplasty was performed using an argon laser (model 900, Coherent, Palo Alto, California), anesthesia achieved with topical proparacaine hydrochloride 0.5%, and an antireflective coated three-mirror Goldmann goniolens. Laser settings included a 50-μπι spot, a 0.1-second duration, and a power set ting between 400 and 1,200 mW that was suffi cient to induce a visible blanching with occa sional bubble formation. Laser treatment (80 to 85 applications) was delivered to the anterior trabecular meshwork for 360 degrees in both treatment groups. Only one eye of a patient was included in our study. 8 Results were determined as the mean ± standard error of the mean. Statistical analysis used nonparametric techniques for two popula tion distributions (Mann-Whitney test) and for matched samples (Wilcoxon test), and the Fish er's exact test (one-tailed) to compute probabil ities.
Results Sixty patients were randomly assigned to treatment (30 patients to each treatment group). There were no statistical differences between preoperative intraocular pressure (z = 0.1, P = .8) and the number of antiglaucoma medications (z = 0.3, P = .7) between the two groups of patients (22.9 ± 0 . 9 mm Hg and 2.4 ± 0.2 medications for patients treated with apra clonidine before and after laser treatment; 22.6 ± 0.6 mm Hg and 2.4 ± 0.2 medications for patients treated with apraclonidine only after laser treatment). Total amount of applied ener gy and number of laser applications were also similar between the two groups of patients (6.6 ± 0.2 and 6.3 ± 0.2 mj of energy, respectively [z = 1.3, P = .2]; 82.9 ± 1.6 and 81.6 ± 1.9 laser applications, respectively [z = 1.5, P = .1]). Intraocular pressure was significantly re duced in both treatment groups one hour and two hours after argon laser trabeculoplasty (Ta ble 1). Intraocular pressure was similar be tween the two groups at these postoperative time intervals (P = .7) as well. One hour after laser treatment, intraocular pressure was equal to or less than preoperative values in 23 of 30 eyes (76%) treated with apraclonidine both before and after the procedure and in 25 of 30 eyes (83%) treated only after laser treatment (P
TABLE 1 INTRAOCULAR PRESSURE AFTER APRACLONIDINE INSTILLATION INTRAOCULAR PRESSURE (MEAN±SEM)·
Preoperative One hour postoperative Two hours postoperative
BEFORE AND
ONLY AFTER
AFTER LASER TRABECULOPLASTY
LASER TRABECULOPLASTY
22.6±0.9 19.5±1.0t 17.5±0.8t
22.6±0.6 18.9±1.0t 17.1 ±0.9*
»SEM indicates standard error of the mean. tSignificant decrease compared to preoperative intraocular pressure, P < .01.
= .4). A similar (P = .5) magnitude of intraocu lar pressure change was present two hours after laser treatment. Both treatment groups had the same (P = .6) number of eyes demonstrating an intraocular pressure increase 1 to 5 mm Hg higher than preoperative levels (Table 2). Intra ocular pressure increase 6 to 10 mm Hg higher than the preoperative level developed in two eyes one hour and in one eye two hours postoperatively in the treatment group that was treat ed with apraclonidine both before and after laser treatment. This magnitude of pressure increase was not observed in the group of patients treated with apraclonidine only after laser treatment. However, this difference was not significant (P = .2).
Discussion Technical aspects of argon laser treatment to the trabecular meshwork may account for tran sient postoperative increases in intraocular pressure. A greater frequency of intraocular pressure increase has been associated with treatment to the posterior trabecular meshwork and 360-degree treatment, 9 the amount of ener gy delivered per laser pulse, 10 and the total energy delivered during the treatment ses sion. 1 However, marked intraocular pressure increases may still develop with anterior tra becular laser burn placement and after 180degree trabecular meshwork treatment. Laser treatment settings in our study were similar in the two apraclonidine treatment groups. Ad ditionally, the treating ophthalmologist was masked to each patient's treatment regimen. The development of postoperative increases in
Vol. 114, No. 1
Apraclonidine and Argon Laser Trabeculoplasty
TABLE 2 POSTOPERATIVE CHANGE IN INTRAOCULAR PRESSURE AFTER APRACLONIDINE INSTILLATION BEFORE AND
ONLY AFTER
AFTER LASER
LASER
TRABECULOPLASTY TRABECULOPLASTY POSTOPERATIVE
(N=30)
(N=30)
NO. (%)
NO. (%)
23 (76)
25 (83)
5(17)
5(17)
INTERVAL OF INTRAOCULAR PRESSURE CHANGE
One hour postoperatively Intraocular pressure spreoperative level Intraocular pressure increase of 1 to 5mmHg Intraocular pressure increase of 6 to 10 mm Hg Two hours postoperatively Intraocular pressure £ preoperative level Intraocular pressure increase of 1 to 5 mm Hg Intraocular pressure increase of 6 to 10 mm Hg
2 (7)
—
27 (90)
28 (93)
2 (7)
2 (7)
1 (3)
—
intraocular pressure after laser trabeculoplasty were highly correlated between the two eyes of patients with primary open-angle glaucoma. 8 For this reason, only one eye of a patient was included in our study. Medical treatment of the postoperative in crease in intraocular pressure can be ineffec tive, with some patients requiring filtration surgical procedures. Preoperative treatment with the long-term administration of the cur rently available topical antiglaucoma medica tions, systemic hyperosmotic agents, systemic carbonic anhydrase inhibitors, or topical corticosteroids, has not effectively inhibited the intraocular pressure after laser treatment. 1113 Although treatment with topical pilocarpine reduces trabeculoplasty-induced intraocular pressure increase, 6,14 many patients undergoing glaucoma laser procedures are already being treated with this and other antiglaucoma medi cations. This may account for the inability of these drugs to have a major effect on reducing laser-induced intraocular pressure increases. Our results confirmed previous observations on the efficacy of topical apraclonidine 1% in preventing acute increases in intraocular pres sure after 360-degree argon laser trabeculo plasty (Table 1). Apraclonidine instillation im mediately after laser trabeculoplasty in eyes with open-angle glaucoma is equally effective
21
as apraclonidine instillation both one hour be fore and immediately after the procedure in preventing early (one- and two-hour) postoper ative laser-induced increases in intraocular pressure. Both treatment regimens reduced the frequency of an acute increase in intraocular pressure, which is frequently observed without apraclonidine pretreatment after argon laser trabeculoplasty; 20% to 40% of eyes with openangle glaucoma have a postoperative increase greater than 10 mm Hg. 11115 Apraclonidine treatment markedly reduces the frequency and magnitude of postoperative increase in intraoc ular pressure after 360-degree argon laser tra beculoplasty (Table 1). Additionally, intraocu lar pressure is significantly reduced one hour and two hours postoperatively (Table 2) when apraclonidine is instilled after laser trabeculo plasty. Although postoperative intraocular pressure increase greater than 10 mm Hg was not measured in our study, this complication develops in up to 8% of eyes treated with apraclonidine both before and after laser tra beculoplasty.3 " 7 Therefore, postoperative intra ocular pressure measurements are required to detect and treat this complication. Our study did not evaluate the effectiveness of a one-drop instillation of apraclonidine be fore laser trabeculoplasty. However, in a recent study one drop of the alpha-adrenergic agonist, brimonidine tartrate, given either before or after argon laser trabeculoplasty was as effec tive in preventing postlaser intraocular pres sure increase as one-drop instillation both before and after laser treatment. 16 Possible benefits from instillation of just one drop of apraclonidine include reduction in the poten tial for medication-induced side effects, reduc tion in cost, and convenience of drug delivery. Treatment with apraclonidine before and af ter laser iridotomy 17 and posterior capsulotomy18 prevented postoperative increases in intra ocular pressure. Our results did not confirm the effectiveness of a single instillation of apraclo nidine for these anterior segment laser proce dures.
References 1. Weinreb, R. N., Ruderman, J., Juster, R., and Zweig, K.: Immediate intraocular pressure response to argon laser trabeculoplasty. Am. J. Ophthalmol. 95:279, 1983. 2. Thomas, J. V., Simmons, R. J., and Belcher,
22
AMERICAN JOURNAL OF OPHTHALMOLOGY
C. D.: Argon laser trabeculoplasty in the presurgical glaucoma patient. Ophthalmology 89:187, 1982. 3. Robin, A. L., Pollack, I. P., House, B., and Enger, C : Effects of ALO 2145 on intraocular pres sure following argon laser trabeculoplasty. Arch. Ophthalmol. 105:646, 1987. 4. Brown, R. H., Stewart, R. H., Lynch, M. G., Crandall, A. S., Mandell, A. I., Wilensky, J. T., Schwartz, A. I., Gaasterland, D. E., DeFaller, J. M., and Higginbotham, E. J.: ALO 2145 reduces the in traocular pressure elevation after anterior segment laser surgery. Ophthalmology 95:378, 1988. 5. Rao, B. S., and Badrinath, S. S.: Efficacy and safety of apraclonidine in patients undergoing ante rior segment laser surgery. Br. J. Ophthalmol. 73:884, 1989. 6. Robin, A. L.: Argon laser trabeculoplasty medi cal therapy to prevent the intraocular pressure rise associated with argon laser trabeculoplasty. Oph thalmic Surg. 22:31, 1991. 7. Allf, B. E., and Shields, M. B.: Early intraocular pressure response to laser trabeculoplasty 180 de grees without apraclonidine versus 360 degrees with apraclonidine. Ophthalmic Surg. 22:539, 1991. 8. Bishop, K. I., Krupin, T., Feitl, M. E., Adelson, A., and Werner, E. B.: Bilateral argon laser trabeculo plasty in primary open-angle glaucoma. Am. J. Oph thalmol. 107:591, 1989. 9. Schwartz, L. W., Spaeth, G. L., Traverse C , and Greenidge, K. C : Variation of techniques on the results of argon laser trabeculoplasty. Ophthalmolo gy 90:781, 1983. 10. Rouhiainen, H. J., Teräsvirta, M. E., and Tuovinen, E. J.: Laser power and postoperative intraocu lar pressure increase in argon laser trabeculoplasty. Arch. Ophthalmol. 105:1352, 1987. 11. Hoskins, H. D., Jr., Hetherington, J., Jr.,
July, 1992
Minckler, D. S., Lieberman, M. F., and Shaffer, R. N.: Complications of laser trabeculoplasty. Oph thalmology 90:796, 1983. 12. Cyrlin, M. N., and Beckman, H.: Low-dose oral glycerin for prevention of post-laser IOP elevation. ARVO abstracts. Supplement to Invest. Ophthalmol. Vis. Sci. Philadelphia, J. B. Lippincott, 1987, p. 272. 13. Ruderman, J. M., Zweig, K. O., Wilensky, J. T., and Weinreb, R. N.: Effects of corticosteroid pretreat ment on argon laser trabeculoplasty. Am. J. Ophthal mol. 96:84, 1983. 14. Ofner, S., Samples, J. R., and Van Buskirk, E. M.: Pilocarpine and the increase in intraocular pressure after trabeculoplasty. Am. J. Ophthalmol. 97:647, 1984. 15. Krupin, T., Kolker, A. E., Kass, M. A., and Becker, B.: Intraocular pressure the day of argon laser trabeculoplasty in primary open-angle glaucoma. Ophthalmology 91:361, 1984. 16. Spaeth, G. L„ David, R., Clevenger, C. E., Perell, H. F., and Siegel, L. I.: The effects of brimonidine tartrate on the incidence of intraocular pressure (IOP) spikes following argon laser trabeculoplasty (ALT). ARVO abstracts. Supplement to Invest. Oph thalmol. Vis. Sci. Philadelphia, J. B. Lippincott, 1992,. p. 1159. 17. Robin, A. L., Pollack, I. P., and deFaller, J. M.: Effects of topical ALO 2145 (p-aminoclonidine hydrochloride) on the acute intraocular pressure rise after argon laser iridotomy. Arch. Ophthalmol. 105:1208, 1987. 18. Pollack, I. P., Brown, R. H., Crandall, A. S., Robin, A. L., Stewart, R. H., and White, G. L.: Pre vention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topi cal 1% apraclonidine. Arch. Ophthalmol. 106:754, 1988.