Prophylactic Use Ofacetazolamide to Prevent Intraocular Pressure Elevation Following Nd-YAG Laser Posterior Capsulotomy

136 BriitishJounalofphthalmology 1993; 77:136-138

ORIGINAL ARTICLES - Clinical science Br J Ophthalmol: first published as 10.1136/bjo.77.3.136 on 1 March 1993. Downloaded from

Prophylactic use ofacetazolamide to prevent intraocular pressure elevation following Nd-YAG laser posterior capsulotomy

Ioannis D Ladas, George P Pavlopoulos, Stefanos N Kokolakis, George P Theodossiadis

Abstract capsule was sufficiently opacified to cause an Fifty four eyes of 54 patients undergoing objective decrease in best corrected visual acuity. Nd-YAG laser posterior capsulotomy were None ofthe patients had a history ofglaucoma or randomly assigned to pretreatment with either an IOP greater than 21 mm Hg before treatment. 125 mg of oral acetazolamide (group A) or Patients in whom pre-existing or current uveitis placebo (group B). During the first 3 hours was present were excluded from the series. foliowing capsulotomy, an intraocular pres- Informed consent was obtained from all the sure (IOP) rise of at least 10 mm Hg was patients. recorded in eight of the 26 eyes of group B Just before inclusion in the study, each patient (30.8%) and in none of the 28 eyes of group A underwent ophthalmic assessment of both eyes; (p<0Ol). A rise of at least 5 mm Hg was it included best corrected Snellen visual acuity, recorded in 16/26 (61.5%) and 4/28 (14.3%) biomicroscopy, and applanation tonometry eyes respectively (p<0.001). Three eyes of (baseline IOP). One hour before laser capsul- group B developed an IOP greater than 35 mm otomy patients received orally either 125 mg of Hg. We found that pretreatment with a low acetazolamide sodium (28 patients) or placebo dose of acetazolamide is highly effective in (26 patients) in a randomised, double-masked preventing IOP elevation following Nd-YAG fashion. IOPs were measured before cap- laser posterior capsulotomy. sulotomy, and at 1, 3, and 24 hours after (Br3r Ophthalmol 1993; 77: 136-138) capsulotomy. All posterior capsulotomies were performed by one of the authors (IDL), after topical Intraocular pressure (IOP) elevation is a very anaesthesia with one drop of 0 5% proparacaine http://bjo.bmj.com/ frequent complication ofneodymium-YAG (Nd- hydrochloride. A Peyman wide field YAG laser YAG) laser posterior capsulotomy.'-'0 Although contact lens (OPY-1[25) was used in each case. this IOP elevation, which characteristically Before capsulotomy the eyes of all patients were reaches a peak within the first 3 postoperative dilated with one drop of a mixture of 5% hours, usually resolves without sequelae, it may phenylephrine and 1% tropicamide. We used a lead to visual field loss and/or loss of central Q-switched Nd-YAG laser (Pegasus 3002, vision, particularly in eyes with pre-existing Rodenstock) with the Nd-YAG laser beam retro- on October 3, 2021 by guest. Protected copyright. glaucomatous damage.4 10-12 focused approximately 0 3 mm behind the Various topical ocular hypotensive agents helium-neon beam focused on the capsule. A have been used prophylactically in an attempt to single application technique was used and the prevent the postlaser IOP rise. Pretreatment burst mode was not employed. Our intention with topical 1% apraclonidine'0-5 or 0 5% was to create a 3-4 mm diameter opening in the levobunolol'6 proved very effective, while topical centre of the opacified capsule using the least 0 5% timolol maleate'7-'9 or 4% pilocarpine'920 amount of total laser energy. provided only partial protection. After the capsulotomy, all eyes received one We designed this prospective, randomised, drop of 0 1% dexamethasone sodium phosphate double-masked study to evaluate whether oral three times daily for 3 days. No additional acetazolamide given in a very low dose is effec- medical therapy was given to any patient for a Department of Ophthalmology, Athens tive prophylaxis for the IOP rise following period of 24 hours, unless the measured IOP University School of routine Nd-YAG laser posterior capsulo- was greater than 35 mm Hg. Ifthe IOP exceeded Medicine, Athens, tomy. 35 mm Hg, the patient was treated with one Greece I D Ladas drop 0-5% timolol maleate twice daily and G P Pavlopoulos 250 mg of oral acetazolamide four times daily. S N Kokolakis Subjects and methods The patient was then observed until the IOP P G Theodossiadis Fifty four eyes of 54 patients undergoing Nd- decreased to below 25 mm Hg. Correspondence to: Dr loannis D Ladas, YAG laser posterior capsulotomy because of Numerical data were recorded as mean (SD). 8 Megalou Alexandrou Street, posterior capsule opacification after extra- Statistical significance for data comparison 152 36 P Penteli, Athens, Greece. capsular cataract extraction and implantation of between patient groups was analysed using Accepted for publication posterior chamber intraocular lens were pro- analysis ofvariance or XI analysis; p values ofless 27 November 1992 spectively selected. In every case, the posterior than 0-01 were considered significant. 137

Results Table 3 Mean (SD) change in IOPfrom baseline Fifty four patients entered the study. Three patients treated with placebo were removed from Acetazolamide Placebo Time* (hours) n Mean (SD) n Mean (SD) p Value the study because of very high IOP (>35 mm Br J Ophthalmol: first published as 10.1136/bjo.77.3.136 on 1 March 1993. Downloaded from Hg). Two other patients of the same group and 1 28 0-7 (2 8) 26 5 8 (5 5) <0 001 one treated with acetazolamide were lost to the 3 28 1L1(29). 25 6-1(63) <0001 24 hour follow-up examination and were not 24 27 0-2 (1-6) 21 1-2 (2-1) NS included in the 24 hour IOP measurements. NS=not significant. *After laser capsulotomy. There was no statistically significant difference between the two groups of patients with Table 4 Patients with IOP elevation >5 and 10 mm Hg regard to sex, age, IOP before prophylactic after laser capsulotomy treatment, and time interval from cataract IOP elevation Acetazolamide (no Placebo (no of surgery to posterior capsulotomy (Table 1). (mm Hg) ofpatients (%)) patients (%)) p Value Additionally, there was no statistically signifi- >5 4/28(14-3) 16/26(61-5) <0 001 cant difference between these groups of patients >10 0/28 (0) 8/26 (30 8) <0 01 with regard to mean laser energy per pulse, number of pulses, or total laser energy used for capsulotomy per patient (Table 2). Just before developed an IOP greater than 25 mm Hg capsulotomy the mean IOP ofthe acetazolamide while nine (34-6%) of the eyes of the placebo group presented a slight decrease because of the group developed an IOP of this level. Further- earlier use ofacetazolamide. more, three eyes (10-7%) of the placebo group During the first 3 hours following capsul- developed an IOP greater than 35 mm Hg (one in otomy, we noticed a mean IOP elevation in the the first and two in the third hour after laser placebo group which ranged from 5 8 to 6a 1 mm treatment) and were treated with additional Hg above baseline IOP. However, the mean IOP antiglaucoma medication. The IOPs dropped to elevation in the acetazolamide group ranged less than 25 mm Hg by the fourth hour after laser from 0-7 to 1-1 mm Hg (p<0001) (Table 3). treatment. Twenty four hours following capsulotomy there There were no acetazolamide side effects was no statistically significant difference in the reported in the treated patients. mean IOP elevation between the two groups of patients (Table 3). Within the first 3 hours following laser treat- Discussion ment, 16 of26 eyes (61-5%) ofthe placebo group IOP elevation is the major complication of Nd- had an IOP elevation greater than 5 mm Hg YAG laser posterior capsulotomy.'1'0 Because compared with only four of 28 eyes (14-3%) of the IOP rise generally reaches its peak during the the acetazolamide group (p<0001) (Table 4). At first 3 hours after laser treatment,59 10 under ideal the same time, eight ofthe 26 eyes (30 8%) ofthe circumstances any drug used to prevent this placebo group developed an IOP rise greater complication must reach its maximum effective- than 10 mm Hg. However, none of the eyes of ness at the same time. Oral acetazolamide the acetazolamide group developed such a high reaches near maximum plasma levels 1 hour after http://bjo.bmj.com/ IOP rise (p<0-001) (Table 4). administration. The maximum IOP reduction is None of the eyes of the acetazolamide group attained within 2 hours and is maintained for 5 to 6 hours after administration."1"2 Thus, a single dose of oral acetazolamide given 1 hour before Table I Patient characteristics Nd-YAG laser posterior capsulotomy should maximum effect, to coin- Acetazolamide Placebo produce hypotensive on October 3, 2021 by guest. Protected copyright. (n=28) (n=26) p Value cide with the time of potential maximum IOP Sex elevation. Female 16(57-1%) 15(57 7%) NS Prophylactic treatment to prevent a complica- Male 12 (42 9%) 11(42-3%) Age (years) tion is worthwhile when this complication is Mean (SD) 69 (8 6) 67-1 (72) NS commonly anticipated, when it has serious Range 48-85 50-83 Time (months)* sequelae and when such a prophylactic treatment Mean(SD) 13(6-1) 11P8(6 7) NS is safe and effective. The results of our study Range 3-26 4-27 IOP (mm Hg)t showed that the prophylactic administration of Mean (SD) 15-4(3) 16-2 (2 7) NS 125 mg of oral acetazolamide to prevent IOP Range 10-21 11-20 elevation following routine Nd-YAG laser NS=not significant. posterior capsulotomy meets the above men- *Interval from cataract surgery. tBefore prophylactic treatment. tioned criteria. Eyes with pre-existing glaucoma were Table 2 Parameters ofapplied Nd-YAG laser energy excluded from our study. Therefore, we cannot Acetaolamide Placebo report if pretreatment with acetazolamide would (n=28) (n=26) p Value be effective in preventing IOP elevation follow- Energy/pulse (mJ/pulse) ing Nd-YAG laser posterior capsulotomy in Mean (SD) 1 9(0 5) 1-8 (0-6) NS these high risk eyes. However, we must assume Range 1-2-3-2 1-03-2 No ofpulses that, especially in glaucomatous eyes which are Mean (SD) 34(18) 37 (20) NS already under a maximal reduction of aqueous Range 4-98 5-76 Total energy/patient (mJ/patient) production because oftreatment with ,6-blockers Mean (SD) 63 (37-2) 62-4 (36-6) NS and acetazolamide, the additional prophylactic Range 6-4-176-4 13-182-4 use of acetazolamide would probably be ineffec- NS=not significant. tive. 138 Ladas, Pavlopoulos, Kokolakis, Theodossiadis

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