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Laser Trabeculoplasty Re-Treatment
Laser Trabeculoplasty Re-Treatment Steven V. 1. Brown, M.D., John V. Thomas, M.D., and Richard J. Simmons, M.D.
Because of inadequate control of intraocular pressure, 26 eyes of 24 patients with primary and secondary open-angle glaucoma who had previously undergone argon laser trabeculoplasty were re-treated. Re-treatment was successful in ten eyes (38%); their average decrease in intraocular pressure was 10.2 mm Hg. After laser re-treatment, three eyes (12%) had marked increases in intraocular pressure, ranging from 10 to 37 mm Hg above baseline, necessitating urgent surgical intervention. ARGON LASER TRABECULOPLASTY is effective in reducing intraocular pressure in patients with primary and secondary open-angle glaucoma.l" Although long-term control of intraocular pressure after trabeculoplasty is achieved in most cases, in some patients intraocular pressure slowly increases to levels high enough to require conventional glaucoma surgery. Re-treatment with laser trabeculoplasty has been reported to be a safe and effective alternative in these patients." This report presents the results of our experience with laser trabeculoplasty retreatment.
SUbjects and
Methods
Twenty-six eyes of 24 patients with primary or secondary open-angle glaucoma underwent retreatment with argon laser trabeculoplasty. All patients had histories of prior laser trabeculoplasty, either in a single 360-degree session or in two 180degree treatments separated by several weeks. All patients considered for re-treatment had had reduc-
Accepted for publication Oct. 25, 1984. From the Glaucoma Consultation Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, and the New England Glaucoma Research Foundation, Boston, Massachusetts. Dr. Brown was a Heed Foundation Fellow (1983-1984). Reprint requests to John V. Thomas, M.D., 100 Charles River Plaza, Boston, MA 02114.
8
tions in intraocular pressure after completion of initial laser trabeculoplasty. Prior to laser re-treatment, patients underwent complete ocular examinations including history, slitlamp examination, Goldmann applanation tonometry, optic disk evaluation, gonioscopy, and visual field examination. Informed consent was obtained from all participants. Patients were treated with an argon laser using a three-mirror Goldmann contact lens. One drop of topical proparacaine hydrochloride 0.5% was administered as anesthesia to the eye to be treated. The laser settings used were a spot size of 50 ILm and a duration of exposure of 0.1 second. The power level was initially set at 1,000 mW and was varied from 800 to 1,200 mW depending on the amount of pigmentation noted on the trabecular meshwork. The desired tissue reaction with each laser application was blanching with formation of a small gas bubble. Since gonioscopic evidence of the exact laser application sites of initial trabeculoplasty treatment was not apparent in most eyes, previous treatment sites on the meshwork were not used to determine the location of re-treatment applications. The junction of the nonpigmented anterior trabecular meshwork and the pigmented filtering meshwork was used as the site of treatment to reduce the chances of intraocular pressure increase" and peripheral anterior synechiae formation." Re-treatment was administered in two sessions. The temporal half of the meshwork was re-treated in one session, and the nasal half was treated about four to six weeks later after assessment of intraocular pressure response. If the pressure increased after the initial 180-degree re-treatment, then the remaining meshwork was not re-treated to avoid the possibility of a further increase in intraocular pressure. Following re-treatment, patients were given topical corticosteroids (1% prednisolone acetate) to be instilled four times daily for five days. Antiglaucoma medications were continued after re-treatment. Follow-up visits were scheduled for the day after re-treatment and at one-, three-, and six-week intervals. Re-treatment was considered successful if the re-
©AMERICAN JOURNAL
OF
OPHTHALMOLOGY 99:8-10, JANUARY, 1985
Vol. 99, No.1
Laser Trabeculoplasty Re-Treatment
treated eye had a decrease in intraocular pressure sufficient to avoid conventional glaucoma surgery. Eyes in which an increase or no change in intraocular pressure occurred were considered re-treatment failures. Eyes in which further optic nerve damage or visual field loss occurred despite a reduction in intraocular pressure were also considered retreatment failures.
Results Among the 26 eyes undergoing re-treatment, 20 eyes had primary open-angle glaucoma, four eyes had pseudoexfoliative glaucoma, and two eyes had pigmentary glaucoma. The mean patient age was 61.8 years (range, 34 to 79 years). There were 12 men and 14 women. All patients were white. Twentythree eyes were phakic; one of the three aphakic eyes was pseudophaldc. The average intraocular pressure before the first laser trabeculoplasty was 30 mm Hg (range, 18 to 54 mm Hg). The average lowest intraocular pressure, two months after completion of initial trabeculoplasty, was 18.2 mm Hg, which represented an average reduction of 39.3% (P <.01). All 26 eyes in this study had reductions in intraocular pressure after initial laser trabeculoplasty. When evaluated just before laser re-treatment, 16 (62%) eyes had subsequent increase of the intraocular pressure to levels above the lowest pressure achieved after treatment. In these 16 eyes, the average increase in intraocular pressure was 13.9 mm Hg, which represented an average increase of 60.4% above the lowest pressure recorded after initial trabeculoplasty. As a group, however, the 26 eyes had an average increase of 37.9% above the lowest intraocular pressure recorded after initial trabeculoplasty when evaluated just before retreatment. The average length of time from completion of initial trabeculoplasty to just before re-treatment was 16.0 months (range, 2.5 to 42
9
months). The average length of follow-up after retreatment was five months (range, 0.4 to 24 months). The average intraocular pressure before laser retreatment for all eyes was 25.1 mm Hg. The average lowest intraocular pressure for all eyes after retreating some or all of the angle was 23.3 mm Hg. This represented an average reduction of 7.2%, which was not significant (P >.4). Following re-treatrnent, ten eyes had increases in intraocular pressure averaging 9.9 mm Hg and were considered re-treatment failures. Seven of these ten eyes had increases ranging from 1 to 9 mm Hg above baseline. The remaining three eyes had increases ranging from 10 to 37 mm Hg above baseline. Eight of ten eyes with increased intraocular pressures after re-treatment demonstrated fairly rapid progression of optic nerve damage and visual field loss and underwent surgery within one month after retreatment. Following re-treatment, 14 eyes had decreases in intraocular pressure averaging 10.4 mm Hg. Ten of these 14 eyes, with an average reduction of 10.2 mm Hg and no further optic nerve damage or visual field loss, did not require surgery and were considered successes after an average follow-up of 5.2 months. Eyes with higher intraocular pressure before laser re-treatment (after initial trabeculoplasty) had greater reductions in pressure after retreatment than eyes with lower pressure before retreatment (Table 1). The remaining four eyes .had progression of optic nerve damage and visual field loss despite an average reduction in intraocular pressure of 5.5 mm Hg and were considered re-treatment failures. Following re-treatment, two eyes had no change in intraocular pressure and were considered failures. The effect of laser re-treatment on a small group of eyes with secondary glaucoma and glaucoma associated with aphakia and pseudophakia is shown in Table 2. All patients were found to require the same maximum tolerated antiglaucoma medications after laser re-treatment as they did prior to therapy.
TABLE 1 AVERAGE CHANGE IN INTRAOCULAR PRESSURE IN SUCCESSFULLY RE·TREATED EYES INTRAOCULAR PRESSURE
AVERAGE CHANGE IN INTRAOCULAR
BEFORE LASER
NO. OF
PRESSURE AFTER LASER
RE·TREATMENT (MM HG)
EYES
RE·TREATMENT (MM HG)
% REDUCTION
2:35 2:30-34 2:25·29 2:20-24
2 1 2 5
-29.0 -16.0 -11.5 -5.4
62.5 50.0 42.5 24.5
10
January, 1985
AMERICAN JOURNAL OF OPHTHALMOLOGY
TABLE 2 EFFECT OF RE-TREATMENT IN SECONDARY GLAUCOMAS
TYPE OF GLAUCOMA
Pseudoexfoliative Pigmentary Aphakic Pseudophakic
NO. OF EYES
4 2
2 1
References
AVERAGE CHANGE IN INTRAOCULAR PRESSURE (MMHG)
-9.7 +6.5 -5.0
o
Discussion Laser trabeculoplasty re-treatment appears to be a satisfactory means of reducing intraocular pressure in some patients, but success is likely only in a minority of patients and the risk of serious pressure increase is great. Although a direct comparison between our study and that of Starita and associates" is not possible, they concluded that repeating laser trabeculoplasty is a safe and effective alternative to surgical intervention. In our series, re-treatment made conventional glaucoma surgery unnecessary in ten eyes (38%); eyes; however, this is significantly less than the 82% to 87% success rates reported with initial laser trabeculoplasty.P:" In addition, increase in intraocular pressure following re-treatment was a potentially major complication. Patients should be cautioned that the probability of success of retreatment is much less than with the initial treatment, and that urgent surgical intervention soon after re-treatment may be necessary.
1. Wise, J. B., and Witter, S.: Argon laser therapy for open angle glaucoma. A pilot study. Arch. OphthalmoI. 97:319, 1979. 2. Wise, J. B.: Long term control of adult open angle glaucoma by argon laser treatment. Ophthalmology 88:197, 1981. 3. Schwartz, A. 1., Whitten, M. E., Bleiman, B., and Martin, D.: Argon laser trabecular surgery in uncontrolled phakic open angle glaucoma. Ophthalmology 88:203, 1981. 4. Forbes, M., and Bansal, R. K.: Argon laser goniophotocoagulation of the trabecular meshwork in open angle glaucoma. Glaucoma 4:100, 1982. 5. Pohjanpelto, P.: Argon laser treatment of the anterior chamber angle for increased intraocular pressure. Acta Ophthalmol. 59:211, 1981. 6. Wilensky, J. T., and [ampol, 1. M.: Laser therapy for open angle glaucoma. Ophthalmology 88:213, 1981. 7. Robin, A. 1., and Pollack, I. P.: Argon laser trabeculoplasty in secondary forms of open angle glaucoma. Arch. Ophthalmol. 101:382, 1983. 8. Thomas, J. V., Simmons, R. J., and Belcher, C. D.: Argon laser trabeculoplasty in the presurgical glaucoma patient. Ophthalmology 89:187, 1982. 9. Starita, R. J., Fellman, R. 1., Spaeth, G. 1., and Poryzees, E.: The effect of repeating full-circumference argon laser trabeculoplasty. Ophthalmic Surg. 15:41, 1984. 10. Thomas, J. V.: Laser trabeculoplasty. In Belcher, C. D., Thomas, J. V., and Simmons, R. J. (eds.): Photocoagulation in Glaucoma and Anterior Segment Disease. Baltimore, Williams and Wilkins, 1983, chap. 5. 11. Traverso, C. E., Greenridge, K. c., and Spaeth, G. 1.: Formation of peripheral anterior synechiae following argon laser trabeculoplasty. Arch. Ophthalmol. 102:861, 1984.
Because of inadequate control of intraocular pressure, 26 eyes of 24 patients with primary and secondary open-angle glaucoma who had previously undergone argon laser trabeculoplasty were re-treated. Re-treatment was successful in ten eyes (38%); their average decrease in intraocular pressure was 10.2 mm Hg. After laser re-treatment, three eyes (12%) had marked increases in intraocular pressure, ranging from 10 to 37 mm Hg above baseline, necessitating urgent surgical intervention. ARGON LASER TRABECULOPLASTY is effective in reducing intraocular pressure in patients with primary and secondary open-angle glaucoma.l" Although long-term control of intraocular pressure after trabeculoplasty is achieved in most cases, in some patients intraocular pressure slowly increases to levels high enough to require conventional glaucoma surgery. Re-treatment with laser trabeculoplasty has been reported to be a safe and effective alternative in these patients." This report presents the results of our experience with laser trabeculoplasty retreatment.
SUbjects and
Methods
Twenty-six eyes of 24 patients with primary or secondary open-angle glaucoma underwent retreatment with argon laser trabeculoplasty. All patients had histories of prior laser trabeculoplasty, either in a single 360-degree session or in two 180degree treatments separated by several weeks. All patients considered for re-treatment had had reduc-
Accepted for publication Oct. 25, 1984. From the Glaucoma Consultation Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, and the New England Glaucoma Research Foundation, Boston, Massachusetts. Dr. Brown was a Heed Foundation Fellow (1983-1984). Reprint requests to John V. Thomas, M.D., 100 Charles River Plaza, Boston, MA 02114.
8
tions in intraocular pressure after completion of initial laser trabeculoplasty. Prior to laser re-treatment, patients underwent complete ocular examinations including history, slitlamp examination, Goldmann applanation tonometry, optic disk evaluation, gonioscopy, and visual field examination. Informed consent was obtained from all participants. Patients were treated with an argon laser using a three-mirror Goldmann contact lens. One drop of topical proparacaine hydrochloride 0.5% was administered as anesthesia to the eye to be treated. The laser settings used were a spot size of 50 ILm and a duration of exposure of 0.1 second. The power level was initially set at 1,000 mW and was varied from 800 to 1,200 mW depending on the amount of pigmentation noted on the trabecular meshwork. The desired tissue reaction with each laser application was blanching with formation of a small gas bubble. Since gonioscopic evidence of the exact laser application sites of initial trabeculoplasty treatment was not apparent in most eyes, previous treatment sites on the meshwork were not used to determine the location of re-treatment applications. The junction of the nonpigmented anterior trabecular meshwork and the pigmented filtering meshwork was used as the site of treatment to reduce the chances of intraocular pressure increase" and peripheral anterior synechiae formation." Re-treatment was administered in two sessions. The temporal half of the meshwork was re-treated in one session, and the nasal half was treated about four to six weeks later after assessment of intraocular pressure response. If the pressure increased after the initial 180-degree re-treatment, then the remaining meshwork was not re-treated to avoid the possibility of a further increase in intraocular pressure. Following re-treatment, patients were given topical corticosteroids (1% prednisolone acetate) to be instilled four times daily for five days. Antiglaucoma medications were continued after re-treatment. Follow-up visits were scheduled for the day after re-treatment and at one-, three-, and six-week intervals. Re-treatment was considered successful if the re-
©AMERICAN JOURNAL
OF
OPHTHALMOLOGY 99:8-10, JANUARY, 1985
Vol. 99, No.1
Laser Trabeculoplasty Re-Treatment
treated eye had a decrease in intraocular pressure sufficient to avoid conventional glaucoma surgery. Eyes in which an increase or no change in intraocular pressure occurred were considered re-treatment failures. Eyes in which further optic nerve damage or visual field loss occurred despite a reduction in intraocular pressure were also considered retreatment failures.
Results Among the 26 eyes undergoing re-treatment, 20 eyes had primary open-angle glaucoma, four eyes had pseudoexfoliative glaucoma, and two eyes had pigmentary glaucoma. The mean patient age was 61.8 years (range, 34 to 79 years). There were 12 men and 14 women. All patients were white. Twentythree eyes were phakic; one of the three aphakic eyes was pseudophaldc. The average intraocular pressure before the first laser trabeculoplasty was 30 mm Hg (range, 18 to 54 mm Hg). The average lowest intraocular pressure, two months after completion of initial trabeculoplasty, was 18.2 mm Hg, which represented an average reduction of 39.3% (P <.01). All 26 eyes in this study had reductions in intraocular pressure after initial laser trabeculoplasty. When evaluated just before laser re-treatment, 16 (62%) eyes had subsequent increase of the intraocular pressure to levels above the lowest pressure achieved after treatment. In these 16 eyes, the average increase in intraocular pressure was 13.9 mm Hg, which represented an average increase of 60.4% above the lowest pressure recorded after initial trabeculoplasty. As a group, however, the 26 eyes had an average increase of 37.9% above the lowest intraocular pressure recorded after initial trabeculoplasty when evaluated just before retreatment. The average length of time from completion of initial trabeculoplasty to just before re-treatment was 16.0 months (range, 2.5 to 42
9
months). The average length of follow-up after retreatment was five months (range, 0.4 to 24 months). The average intraocular pressure before laser retreatment for all eyes was 25.1 mm Hg. The average lowest intraocular pressure for all eyes after retreating some or all of the angle was 23.3 mm Hg. This represented an average reduction of 7.2%, which was not significant (P >.4). Following re-treatrnent, ten eyes had increases in intraocular pressure averaging 9.9 mm Hg and were considered re-treatment failures. Seven of these ten eyes had increases ranging from 1 to 9 mm Hg above baseline. The remaining three eyes had increases ranging from 10 to 37 mm Hg above baseline. Eight of ten eyes with increased intraocular pressures after re-treatment demonstrated fairly rapid progression of optic nerve damage and visual field loss and underwent surgery within one month after retreatment. Following re-treatment, 14 eyes had decreases in intraocular pressure averaging 10.4 mm Hg. Ten of these 14 eyes, with an average reduction of 10.2 mm Hg and no further optic nerve damage or visual field loss, did not require surgery and were considered successes after an average follow-up of 5.2 months. Eyes with higher intraocular pressure before laser re-treatment (after initial trabeculoplasty) had greater reductions in pressure after retreatment than eyes with lower pressure before retreatment (Table 1). The remaining four eyes .had progression of optic nerve damage and visual field loss despite an average reduction in intraocular pressure of 5.5 mm Hg and were considered re-treatment failures. Following re-treatment, two eyes had no change in intraocular pressure and were considered failures. The effect of laser re-treatment on a small group of eyes with secondary glaucoma and glaucoma associated with aphakia and pseudophakia is shown in Table 2. All patients were found to require the same maximum tolerated antiglaucoma medications after laser re-treatment as they did prior to therapy.
TABLE 1 AVERAGE CHANGE IN INTRAOCULAR PRESSURE IN SUCCESSFULLY RE·TREATED EYES INTRAOCULAR PRESSURE
AVERAGE CHANGE IN INTRAOCULAR
BEFORE LASER
NO. OF
PRESSURE AFTER LASER
RE·TREATMENT (MM HG)
EYES
RE·TREATMENT (MM HG)
% REDUCTION
2:35 2:30-34 2:25·29 2:20-24
2 1 2 5
-29.0 -16.0 -11.5 -5.4
62.5 50.0 42.5 24.5
10
January, 1985
AMERICAN JOURNAL OF OPHTHALMOLOGY
TABLE 2 EFFECT OF RE-TREATMENT IN SECONDARY GLAUCOMAS
TYPE OF GLAUCOMA
Pseudoexfoliative Pigmentary Aphakic Pseudophakic
NO. OF EYES
4 2
2 1
References
AVERAGE CHANGE IN INTRAOCULAR PRESSURE (MMHG)
-9.7 +6.5 -5.0
o
Discussion Laser trabeculoplasty re-treatment appears to be a satisfactory means of reducing intraocular pressure in some patients, but success is likely only in a minority of patients and the risk of serious pressure increase is great. Although a direct comparison between our study and that of Starita and associates" is not possible, they concluded that repeating laser trabeculoplasty is a safe and effective alternative to surgical intervention. In our series, re-treatment made conventional glaucoma surgery unnecessary in ten eyes (38%); eyes; however, this is significantly less than the 82% to 87% success rates reported with initial laser trabeculoplasty.P:" In addition, increase in intraocular pressure following re-treatment was a potentially major complication. Patients should be cautioned that the probability of success of retreatment is much less than with the initial treatment, and that urgent surgical intervention soon after re-treatment may be necessary.
1. Wise, J. B., and Witter, S.: Argon laser therapy for open angle glaucoma. A pilot study. Arch. OphthalmoI. 97:319, 1979. 2. Wise, J. B.: Long term control of adult open angle glaucoma by argon laser treatment. Ophthalmology 88:197, 1981. 3. Schwartz, A. 1., Whitten, M. E., Bleiman, B., and Martin, D.: Argon laser trabecular surgery in uncontrolled phakic open angle glaucoma. Ophthalmology 88:203, 1981. 4. Forbes, M., and Bansal, R. K.: Argon laser goniophotocoagulation of the trabecular meshwork in open angle glaucoma. Glaucoma 4:100, 1982. 5. Pohjanpelto, P.: Argon laser treatment of the anterior chamber angle for increased intraocular pressure. Acta Ophthalmol. 59:211, 1981. 6. Wilensky, J. T., and [ampol, 1. M.: Laser therapy for open angle glaucoma. Ophthalmology 88:213, 1981. 7. Robin, A. 1., and Pollack, I. P.: Argon laser trabeculoplasty in secondary forms of open angle glaucoma. Arch. Ophthalmol. 101:382, 1983. 8. Thomas, J. V., Simmons, R. J., and Belcher, C. D.: Argon laser trabeculoplasty in the presurgical glaucoma patient. Ophthalmology 89:187, 1982. 9. Starita, R. J., Fellman, R. 1., Spaeth, G. 1., and Poryzees, E.: The effect of repeating full-circumference argon laser trabeculoplasty. Ophthalmic Surg. 15:41, 1984. 10. Thomas, J. V.: Laser trabeculoplasty. In Belcher, C. D., Thomas, J. V., and Simmons, R. J. (eds.): Photocoagulation in Glaucoma and Anterior Segment Disease. Baltimore, Williams and Wilkins, 1983, chap. 5. 11. Traverso, C. E., Greenridge, K. c., and Spaeth, G. 1.: Formation of peripheral anterior synechiae following argon laser trabeculoplasty. Arch. Ophthalmol. 102:861, 1984.