The rarity of clinically significant rise in intraocular pressure after laser peripheral iridotomy with apraclonidine

Objective

To determine the incidence of intraocular pressure (IOP) rise of varying degrees after laser peripheral iridotomy (LPI) in patients with and without glaucoma treated perioperatively with pilocarpine and apraclonidine.

Design

A retrospective chart review.

Participants

A total of 289 eyes in 179 patients with narrow occludable angles (NOA) (N = 148), open-angle glaucoma or ocular hypertension (OAG) (N = 115), or chronic-angle closure glaucoma (CACG) (N = 26) were reviewed.

Main outcome measures

The difference between preoperative and postoperative IOP, absolute postop- erative IOP, and the need for acute IOP-lowering treatment was noted.

Results

Only 1.1% (95% confidence interval [CI], 0.03%–5.8%; 1 of 94) of patients and 0.7% (95% CI, 0.02%–3.7%; 1 of 148) of eyes with NOA experienced a rise of more than 10 mmHg 1 to 2 hours after LPI. The incidence of postoperative IOP greater than 25 mmHg and acute postoperative IOP-lowering management was 0% (95% CI, 0%–3.8%). Intraocular pressure in 1 of 115 eyes (0.9%, 95% CI, 0.02%–4.7%) with OAG rose more than 10 mmHg, requiring acute treatment. None of the 26 CACG eyes experienced a rise of more than 10 mmHg (95% CI, 0%–13.2%).

Conclusion

The IOP rise that requires further intervention after LPI with the perioperative use of pilocarpine and apraclonidine is very uncommon. In patients with NOA, routine postiridotomy IOP monitoring may not be required.     

Intraocular pressure rise after argon laser trabeculoplasty.

Eighty-four eyes received 107 argon laser trabeculoplasty treatments at Beth Israel Medical Center between 1982 and 1984 for advanced primary and secondary glaucoma. The prelaser mean pressure was 20.25 mmHg. Pressures taken 1 1/2 hours postoperatively varied widely: the pressure rose after 47 treatments and fell or remained the same after 60. Significant increases in pressure occurred in 10 eyes, after 12 treatments; 42% of these had received burns of 0.8 watts or greater. Pressure changes were correlated with laser burn energy level. Both patients who had significant increases in pressure initially were retreated again--in the same eye--at another time had similar increases in postoperative pressure again, even with lower energy levels. Comparison with the results of previous reports highlights the advantages of limited treatment to the anterior trabeculum with low energy levels.     

Corneal endothelial decompensation after argon laser iridotomy.

Focal corneal edema overlying the site of argon laser iridotomy followed by generalized corneal decompensation developed in six eyes of five patients. The average interval between the iridotomy and the development of focal edema was 3 years, with generalized edema appearing an average of 3.5 months later. Light, scanning and transmission electron microscopy of tissue removed at the time of corneal transplantation showed abnormalities characteristic of Fuchs' dystrophy in two patients. Possible contributing factors include episodes of intraocular pressure elevation, cornea guttata and the use of high total amounts of energy during laser iridotomy.     

Retinal damage after argon laser iridotomy

We conducted a prospective clinical study to evaluate potential retinal damage after argon laser iridotomy in 25 eyes of 22 patients with primary chronic angle-closure glaucoma. Kinetic perimetry and ophthalmoscopy showed no detectable damage. Iridotomy required a mean of 11.4 +/- 10 joules to achieve a patent coloboma of 200 micron after one to three sessions. Dark-prone and mydriasis tests were performed one month after surgery. Pilocarpine was discontinued in all cases. Both static perimetry and fluorescein angiography of the midperiphery corresponding to the meridian of laser coloboma done six months after surgery showed focal damage. There was no damage in control tests of the same eyes in an opposite area of the retina.     

Acute intraocular pressure response to argon laser iridotomy

Argon laser iridotomy (ALI) was performed in 50 eyes for prophylactic treatment of anatomically narrow iridocorneal angles and in 50 eyes for therapy of chronic angle-closure glaucoma. Intraocular pressure was increased 6 mmHg or more 1 to 2 hours after ALI in 19 of 50 eyes with anatomical narrow iridocorneal angles and in 23 of 50 eyes with chronic angle-closure glaucoma. Increases greater than 20 mmHg over baseline value occurred in 5 of 50 eyes with narrow iridocorneal angles and in 7 of 50 eyes with chronic angle-closure glaucoma. A clinically significant increase in intraocular pressure (defined as a pressure 30 mmHg or greater and 40% or more increased over the pre-laser value) occurred 1 to 2 hours after ALI in 11 of 50 eyes with narrow iridocorneal angles and in 17 of 50 eyes with chronic angle-closure glaucoma. There was no statistical difference (chi square P greater than 0.3) in the incidence of this complication in the two groups. Additional medical therapy was effective in lowering the acute laser-induced elevation in intraocular pressure. Patient diagnosis, patient demographics, preoperative glaucoma medication and laser treatment parameters did not predict which eyes would develop this complication. Eyes which did not have a clinically significant elevation in intraocular pressure 1 to 2 hours after ALI did not show a later increase at 24 hours.     

Corneal endothelial changes after argon laser iridotomy

We used a continuous-wave argon laser to produce iridotomies in 28 eyes of 17 patients (12 women and five men ranging in age from 44 to 84 years) with angle-closure glaucoma. We photographed the central corneal endothelium with a contact specular microscope before and after the laser iridotomy was produced. The mean number of cells before treatment was 2,516 cells/mm2 and the mean number after treatment was 2,391 cells/mm2. The mean decrease, therefore, was 125 cells/mm2. This decrease was not statistically significant (P = .09). Retrogression analysis failed to show a correlation between the amount of energy necessary to produce the iridotomy and a decrease in endothelial cell density. Retrogression analysis also failed to show a correlation between the change in endothelial cell density and the time between the laser iridotomy and the performance of postoperative specular microscopy (one to 41 weeks).     

Evaluation of phototoxic retinal damage after argon laser iridotomy

We performed several visual function tests in 17 eyes (ten patients) before and after argon laser iridotomy in an effort to detect diffuse photochemical damage to photoreceptors caused by exposure to the intense, blue-green light that is transmitted into the posterior segment as the iridotomy is created and enlarged. No change was detected in static threshold sensitivity in the central 30 degrees of the field (Octopus perimeter), color sensitivity (Farnsworth-Munsell 100-Hue test), or visual acuity. Contrast sensitivity showed a small increase at low spatial frequencies and a small decrease at high spatial frequencies. The latter change was small and not necessarily laser related, but precautions to limit laser exposure of the posterior pole are prudent.     

Use of latanoprost to reduce acute intraocular pressure rise following neodymium: Yag laser iridotomy

PURPOSE: To evaluate the efficacy of latanoprost in reducing acute intraocular pressure (IOP) elevation after neodymium:Yag laser iridotomy (LI). METHODS: Primary angle-closure glaucoma (PACG) eyes were randomized to receive premedication with latanoprost and pilocarpine or with pilocarpine only before LI. Postoperative IOP changes were compared with Wilcoxon signed-ranks test using the fellow eyes of 47 patients who had one eye in each group. RESULTS: Postoperative pressure spikes were significantly lower (p = 0.010) in the latanoprost group (4.1 +/- 5.0 mmHg) than in the control group (6.7 +/- 7.0 mmHg). Mean elevation of IOP was less in the latanoprost group than in the control group at 1 hour (2.5 +/- 4.8 versus 4.1 +/- 4.7 mmHg, p = 0.013) and 2 hours (0.8 +/- 5.6 versus 4.4 +/- 8.1 mmHg, p = 0.003) postoperatively. Eleven eyes in the latanoprost group (23.4%) and 20 eyes in the control group (42.6%) developed a rise in IOP > or = 6 mmHg (p = 0.048). CONCLUSION: Latanoprost may reduce the pressure rise following LI in PACG eyes, but its application is limited by a late onset of effect.     

Control of intraocular pressure with apraclonidine hydrochloride after cataract extraction

We conducted a randomly assigned, double-masked, controlled clinical trial to assess the efficacy of 1% apraclonidine hydrochloride in controlling postoperative intraocular pressure increases in patients undergoing extracapsular cataract extraction. Apraclonidine hydrochloride was given either one hour preoperatively or immediately after uncomplicated, extracapsular cataract extraction with posterior chamber intraocular lens implantation and compared with artificial tears given immediately postoperatively. Those who received apraclonidine hydrochloride preoperatively had significantly lower mean intraocular pressure at the first postoperative reading (P = .0005). After preoperative and postoperative apraclonidine hydrochloride, the mean early postoperative intraocular pressure was 19.8 mm Hg and 32.0 mm Hg, respectively, and 27.6 mm Hg after artificial tears. No patient who received preoperative apraclonidine hydrochloride had an intraocular pressure increase to 30 mm Hg or higher postoperatively. Nine of 20 patients (45%) who received postoperative apraclonidine hydrochloride and eight of 18 patients (44%) who received postoperative artificial tears had an increase of intraocular pressure to 30 mm Hg or higher in the early postoperative period. These differences were also highly significant (P = .0005).     

Influence of apraclonidine and pilocarpine alone and in combination on post laser trabeculoplasty pressure rise.

Apraclonidine and pilocarpine have been shown to be effective in reducing the incidence of intraocular pressure (IOP) spikes following argon laser trabeculoplasty. An additional reduction in the incidence of acute pressure rise might theoretically be expected by combining these two effective agents. In a prospective randomised study we compared the ability of apraclonidine and pilocarpine alone and in combination to prevent post laser pressure spikes. Patients receiving regular pilocarpine to either eye were excluded. Seventy five eyes received either apraclonidine (26 eyes), pilocarpine (23 eyes), or both drugs (26 eyes). Apraclonidine 1% was instilled 1 hour before and immediately after, and pilocarpine 4% immediately after trabeculoplasty. IOP was measured before and at 1, 2, and 3 hours following trabeculoplasty. In only two (8%) eyes receiving combined treatment was a pressure rise observed. This frequency was significantly lower than that seen in eyes treated with apraclonidine alone (38%), or pilocarpine alone (39%). The mean fall in IOP at 1, 2, and 3 hours was significantly greater in those eyes receiving combined treatment than in the other two groups.     

Effect of apraclonidine versus dorzolamide on intraocular pressure after phacoemulsification.

BACKGROUND AND OBJECTIVE: To investigate the efficacy of 1% apraclonidine hydrochloride and 2% dorzolamide hydrochloride in controlling postoperative intraocular pressure elevation in patients undergoing phacoemulsification. PATIENTS AND METHODS: A prospective, randomized, double-blind, placebo-controlled study was conducted. Seventy-five patients were randomized to receive either 1% apraclonidine hydrochloride, 2% dorzolamide hydrochloride, or artificial tears immediately after uncomplicated phacoemulsification. Intraocular pressure was measured by Goldmann applanation tonometer 1 to 3 hours preoperatively and 24 hours and 5 days postoperatively. RESULTS: Mean intraocular pressure measured at 24 hours and 5 days after surgery was not significantly different between groups. None of the patients had an elevated intraocular pressure of 30 mm Hg or higher. No marked difference was observed in patient age, preoperative intraocular pressure, mean ultrasound time, degree of nuclear hardness, and amount of postoperative intraocular inflammation between groups. CONCLUSION: Uneventful phacoemulsification involving meticulous cortical and viscoelastic removal does not cause a significant increase in intraocular pressure 24 hours following surgery.     

Control of intraocular pressure elevations after argon laser trabeculoplasty: comparison of brimonidine 0.2% to apraclonidine 1.0%.

OBJECTIVE: To determine whether brimonidine 0.2% can control intraocular pressure (IOP) spikes as well as apraclonidine 1.0% can in those patients undergoing argon laser trabeculoplasty (ALT). DESIGN: Prospective, randomized, double-masked, clinical trial. PARTICIPANTS: A total of 56 eyes of 41 patients with open-angle glaucoma or ocular hypertension were entered in the study; 46 eyes of 41 patients were eventually used for the final analysis. INTERVENTION: Patients were randomized to receive either brimonidine 0.2% or apraclonidine 1.0% before and after 360 degrees ALT. Both patient and physician were masked as to which agent each patient received. MAIN OUTCOME MEASURES: Intraocular pressure measurements were recorded before surgery and at 1, 2, and 4 hours after surgery. The difference between the preoperative IOP (baseline) and the highest recorded postoperative IOP was recorded as the maximum IOP change. The mean of the maximum IOP change for each group was analyzed using a two-sample, one-tailed t test. RESULTS: The mean of the maximum IOP change in the brimonidine 0.2% group was -2.6+/-3.6 mmHg, and the mean for the apraclonidine 1.0% group was -2.3+/-3.7 mmHg (P = 0.8). No patient had a pressure spike greater than 10 mmHg. CONCLUSIONS: Brimonidine 0.2% appears to be as effective as apraclonidine 1.0% in preventing IOP spikes after argon laser trabeculoplasty.     

Efficacy of apraclonidine 1% versus pilocarpine 4% for prophylaxis of intraocular pressure spike after argon laser trabeculoplasty.

OBJECTIVE: The authors compared the efficacy of apraclonidine 1% versus pilocarpine 4% prophylaxis of post-argon laser trabeculoplasty (ALT) intraocular pressure (IOP) spike. DESIGN: Prospective randomized clinical trial. PARTICIPANTS: Two hundred twenty-eight eyes of 228 patients with primary open-angle glaucoma undergoing ALT were studied. INTERVENTION: Patients were given 1 drop of either apraclonidine 1% (n = 114) or pilocarpine 4% (n = 114) 15 minutes before ALT. MAIN OUTCOME MEASURES: Peri-ALT IOPs and incidences of post-ALT IOP spikes at 5 minutes, 1 hour, and 24 hours were compared between the two groups. RESULTS: The two groups were similar in age, race, and medical dependency. Post-ALT mean IOPs at 5 minutes, 1 hour, and 24 hours were significantly lower than pre-ALT mean IOPs in both apraclonidine (P < 0.001) and pilocarpine (P < 0.001) groups. Incidences of IOP spikes greater than 1, 3, and 5 mmHg at 1 hour post-ALT were 21.1%, 14.9%, and 8.8% for the apraclonidine group and 12.3%, 5.3%, and 4.4% for the pilocarpine group (P = 0.076, 0.015, and 0.18 chi-square test). In the apraclonidine prophylaxis group, patients on long-term apraclonidine showed significantly higher incidence of post-ALT IOP spike than the patients without such long-term apraclonidine use (35.7%, 15 of 42 eyes, vs. 12.5%, 9 of 72 eyes; P = 0.003). In addition, peri-ALT pilocarpine prophylaxis tended to be less effective in patients undergoing long-term pilocarpine therapy but without statistical significance (17.4%, 8 of 46 eyes, vs. 9.4%, 6 of 64 eyes; P = 0.17). CONCLUSION: Peri-ALT pilocarpine 4% was at least as effective as, if not more effective than, apraclonidine 1% in post-ALT IOP spike prophylaxis. Peri-ALT apraclonidine prophylaxis was not effective in patients on long-term apraclonidine, and peri-ALT pilocarpine prophylaxis tended to be less effective in patients undergoing long-term pilocarpine therapy. Pilocarpine 4% can be considered as a first-choice drug for post-ALT IOP spike prophylaxis, especially in patients under treatment with apraclonidine.     

Prevention of the immediate intraocular pressure rise following argon laser trabeculoplasty.

A prospective, randomised double-masked study was undertaken to compare the effect of pretreatment with acetazolamide or placebo on the immediate intraocular pressure (IOP) rise following argon laser trabeculoplasty. One hundred eyes (100 patients) underwent 180 degree of laser treatment with a mean of 59 spots of 50 microns size and 800 to 1000 mW power. The IOP was measured during the first three hours after laser treatment, at 24 hours, and at two months. Forty-six patients (92%) in the placebo group had an immediate rise of IOP. The mean rise (SD) for these patients was 8.6 (7.1) mmHg. Fifteen patients (30%) in this group had an IOP rise of greater than 10 mmHg. Nine patients (18%) receiving acetazolamide had an immediate rise of IOP. The mean rise for these patients was 4.3 (3.1) mmHg, and no patient had an increase in IOP of greater than 8 mmHg. Acetazolamide appears to be effective in preventing a critical IOP rise after argon laser trabeculoplasty (p less than 0.0001).     

Effects of argon laser iridotomy on the corneal endothelium

We studied 14 eyes of 14 patients undergoing argon laser peripheral iridotomy for occludable (narrow) anterior chamber angles. Preoperative and postoperative pachymetry and corneal endothelial cell counts by specular microscopy were obtained centrally and in both the treated and nontreated superior quadrants. No significant differences were found between preoperative and postoperative measurements of corneal thickness and endothelial cell counts in any area.     

Low-energy linear-incision neodymium: YAG laser iridotomy versus linear-incision argon laser iridotomy. A prospective clinical investigation

When the Q-switched neodymium: YAG (Nd: YAG) laser is focused through the Wise 103-diopter (D) iridotomy-sphincterotomy lens (103-D lens) at low energy levels, the peripheral iris fibers can be cut individually across the iris tension lines to produce large iridotomies of controllable size. Thirty patients had linear-incision Nd:YAG laser iridotomy in one eye and linear-incision argon laser iridotomy in the other. Two-hour post-laser IOP rises averaged 7.33 mmHg for the Nd:YAG laser and 8.64 mmHg for the argon laser. The argon laser produced lens burns in 9 of 30 eyes, including 7 of 9 blue eyes. No lens damage occurred with the Nd:YAG laser. No corneal or retinal damage was seen with either laser. Local oozing of blood inhibited optical breakdown and required a pause before completion in 5 of 30 eyes with Nd:YAG iridotomy, including 4 of 6 dark brown thick irides. Because the iris fibers must be cut by direct contact with the laser plasma, serial cutting of iris fibers by multiple low-energy plasmas is safer than a single-shot, high-power plasma occupying the full thickness of the iris. Because it is effective and because it avoids the hazards of argon laser iridotomy and of high-power Nd:YAG laser iridotomy, linear incision Nd:YAG laser iridotomy is recommended as the safest method of iridotomy.     

Nicardipine inhibits acute rise of aqueous flare and intraocular pressure induced by argon laser photocoagulation

The purpose of this study was to examine the anti-inflammatory effect of the calcium channel blocker nicardipine. Intraocular inflammation was induced by argon laser photocoagulation of the iris of pigmented rabbits and was assessed by measuring aqueous flare and intraocular pressure. This resulted in a marked increase in the aqueous flare that peaked at approximately one hour following coagulation and returning to the original values after six hours. Intraocular pressure increased within 15 minutes following laser treatment and returned to baseline levels at 60 minutes. Pre-treatment of the rabbits with an intravenous injection of 2 mg/kg of nicardipine completely abolished both the increase in aqueous flare and intraocular pressure induced by laser photocoagulation as compared to the control experiment. Earlier work from the author's group has shown that nicardipine can also block aqueous flare and intraocular pressure increases induced by topical administration of prostaglandin E2. From these combined experiments they would like to draw the conclusion that the inflammatory reaction induced by photocoagulation of the iris is partly mediated by prostaglandins and that blockade of calcium channels by nicardipine can inhibit the effects induced by prostaglandin E2.     

The prevention of an acute rise in intraocular pressure following Q-switched Nd:YAG laser iridotomy with clonidine

We evaluated the ability of topical clonidine to suppress an acute rise in postoperative intraocular pressure (IOP) following Nd:YAG laser iridotomy. A total of 36 eyes (29 patients) with chronic primary angle-closure glaucoma underwent Q-switched Nd:YAG laser iridotomy: 18 eyes were treated topically with 0.5% clonidine ophthalmic solution prior to and immediately following the procedure, and a control group of 18 eyes underwent Nd:YAG laser iridotomy without topical clonidine. The control group was selected to match the clonidine-treated group in terms of preoperative IOP, the extent of peripheral anterior synechia, and the total amount of laser energy delivered. None of the clonidine-treated eyes experienced an IOP rise greater than 4 mm Hg over baseline, wereas 4 of the nontreated eyes (22.2%) developed an IOP rise greater than 10 mm Hg. The mean IOPs were significantly lower during the first 4 h postsurgery in the clonidine-treated eyes.