Agnes S. Y. Poon

Argon laser peripheral iridoplasty versus conventional systemic medical therapy in treatment of acute primary angle-closure glaucoma: A prospective, randomized, controlled trial

OBJECTIVE To study whether argon laser peripheral iridoplasty (ALPI) is as effective and safe as conventional systemic medications in treatment of acute primary angle-closure glaucoma (PACG) when immediate laser peripheral iridotomy is neither possible nor safe. DESIGN Prospective, randomized, controlled trial. PARTICIPANTS Seventy-three eyes of 64 consecutive patients with their first presentation of acute PACG, with intraocular pressure (IOP) levels of 40 mmHg or more, were recruited into the study. INTERVENTION The acute PACG eye of each consenting patient received topical pilocarpine (4%) and topical timolol (0.5%). The patients were then randomized into one of two treatment groups. The ALPI group received immediate ALPI under topical anesthesia. The medical treatment group was given 500 mg of intravenous acetazolamide, followed by oral acetazolamide 250 mg four times daily, and an oral potassium supplement until IOP levels normalized. Intravenous mannitol also was administered to the latter group if the presenting IOP was higher than 60 mmHg. The acute PACG eye of both groups continued to receive topical pilocarpine (1%) until peripheral iridotomy could be performed. MAIN OUTCOME MEASURES Intraocular pressure profile, corneal clarity, symptoms, visual acuity, angle status by indentation gonioscopy, and complications of treatment. RESULTS Thirty-three acute PACG eyes of 32 patients were randomized to receive immediate ALPI, whereas 40 acute PACG eyes of 32 patients had conventional systemic medical therapy. Both treatment groups were matched for age, duration of attack, and IOP at presentation. The ALPI-treated group had lower IOP levels than the medically treated group at 15 minutes, 30 minutes, and 1 hour after the start of treatment. The differences were statistically significant. The difference in IOP levels became statistically insignificant from 2 hours onward. The duration of attack did not affect the efficacy of ALPI in reducing IOP in acute PACG. No serious laser complications occurred, at least in the early postlaser period. CONCLUSIONS Argon laser peripheral iridoplasty significantly is more effective than conventional systemic medications in reducing IOP levels in acute PACG in eyes not suitable for immediate laser peripheral iridotomy within the first 2 hours from the initiation of treatment. Argon laser peripheral iridoplasty is a safe and more effective alternative to conventional systemic medications in the management of acute PACG not amenable to immediate laser peripheral iridotomy.

Efficacy and safety of the Ahmed glaucoma valve implant in Chinese eyes with complicated glaucoma

AIMS To evaluate the efficacy and safety of the Ahmed glaucoma valve implant in Chinese eyes with complicated glaucomas. METHODS This retrospective study reviewed the final intraocular pressure, visual outcome, and incidence of complications in all patients with the Ahmed glaucoma valve implant performed at the Prince of Wales Hospital, Hong Kong, between June 1996 and November 1998. RESULTS A total of 65 eyes from 60 patients were treated with the Ahmed glaucoma implant. At a mean follow up (SD, median) of 21.8 (9.2, 28.0) months (range 6–37 months), the mean intraocular pressure was reduced from 37.0 (SD 12.1) mm Hg before the implant surgery to 16.1 (12.4) mm Hg at the last follow up after surgery. The success rate of intraocular pressure control of <22 mm Hg was achieved in 73.8% of operated eyes. Transient postoperative hypotony with shallow anterior chamber occurred in 10.8% of cases. The most common postoperative complication was the formation of encapsulated bleb (24.6%). CONCLUSIONS The Ahmed glaucoma valve implant appears to be effective and relatively safe for treating complicated glaucomas in Chinese eyes. The success rate is comparable with those reported in non-Asian eyes. Formation of postoperative encapsulated bleb is, however, more commonly encountered.

Re: laser peripheral iridoplasty as initial treatment of acute attack of primary angle-closure: a long-term follow-up study.

PurposeTo study the long-term clinical course and complications of patients with acute primary angle-closure treated with immediate laser peripheral iridoplasty followed by laser peripheral iridotomy. Patients and MethodsConsecutive patients with acute primary angle closure treated with immediate laser peripheral iridoplasty, followed by laser peripheral iridotomy, at the Prince of Wales Hospital from July 1997 through January 2000 were followed up to document the clinical course of their disease and any complications from the laser treatment. Visual acuity, intraocular pressure, gonioscopic findings, corneal and lens clarity, iris appearance, pupillary reaction, and progression of glaucomatous optic neuropathy were evaluated. ResultsThirty eyes of 29 Chinese patients with acute primary angle closure treated initially with either argon or diode laser peripheral iridoplasty were recruited. The mean follow-up period was 33.0 ± 9.3 months. Twenty-one eyes (70%) had no further attack and maintained normal intraocular pressure without medications, and 9 eyes (30%) developed chronic angle-closure glaucoma with peripheral anterior synechiae. All eyes had pigmented laser marks on the peripheral iris, but none had peripheral corneal burn. ConclusionsLong-term follow-up data indicated that 30% of Chinese eyes with acute primary angle closure successfully treated with immediate laser peripheral iridoplasty followed by laser peripheral iridotomy developed peripheral anterior synechiae and an increase in intraocular pressure. There were minimal long-term complications on the cornea and the lens from the laser treatment.

Immediate argon laser peripheral iridoplasty (ALPI) as initial treatment for acute phacomorphic angle-closure (phacomorphic glaucoma) before cataract extraction: A preliminary study

PurposeTo study the safety and efficacy of immediate argon laser peripheral iridoplasty (ALPI) as initial treatment of acute phacomorphic angle-closure (phacomorphic glaucoma) before cataract extraction.MethodsIn all, 10 consecutive patients with acute phacomorphic angle-closure and intraocular pressure (IOP) ⩾40 mmHg were recruited into the study. Each patient received topical atropine (1%) and timolol (0.5%), and immediate ALPI as initial treatment. The IOP at 15, 30, 60, and 120 min, and then 1 day, after ALPI were documented by applanation tonometry. Systemic IOP-lowering drugs were only started if IOP remained above 40 mmHg at 2 h after ALPI. Cataract extraction was subsequently performed as definitive treatment.ResultsIn total, 10 patients (five male, five female), with a mean age±SD of 73.1±10.3 years were recruited. Mean duration of symptomatic attack was 128±232 h. After ALPI, the mean IOP was reduced from 56.1±12.5 to 45.3±14.5 mmHg at 15 min, 37.6±7.5 mmHg at 30 min, 34.2±9.7 mmHg at 60 min, 25.5±8.7 mmHg at 120 min, and 13.6±4.2 mmHg at 1 day. In one patient, systemic acetazolamide was administered, because the IOP remained above 40 mmHg at 2 h after ALPI. All 10 patients had uncomplicated cataract extraction performed within 4 days after ALPI. No complications from the laser procedure were encountered.ConclusionImmediate ALPI, replacing systemic antiglaucomatous medications, appeared to be safe and effective as first-line treatment of acute phacomorphic angle-closure.

To compare argon laser peripheral iridoplasty (ALPI) against systemic medications in treatment of acute primary angle-closure: mid-term results

PurposeTo compare the clinical outcome of argon laser peripheral iridoplasty (ALPI) against systemic medications in treatment of acute primary angle-closure (APAC).MethodsConsecutive patients with APAC were recruited and randomized to receive one of two treatment options: immediate ALPI or systemic acetazolamide±mannitol. All eyes were followed up for at least 6 months after laser iridotomy. Main outcome measures were intraocular pressure (IOP) and requirement for glaucoma medications.ResultsA total of 41 eyes (39 patients) were randomized into the ALPI group, and 38 eyes (32 patients) into the medical treatment group. There were no significant differences between the two groups in sex, age, presenting IOP, and duration of attack. Mean follow-up duration±SD was 15.7±5.8 months. There were no significant differences between the two groups in mean final IOP and requirement for glaucoma medications.ConclusionsThere were no statistically significant differences in mean IOP and requirement for glaucoma drugs between APAC eyes treated with ALPI and systemic medications.

Trabeculectomy with β radiation: Long-term follow-up

Abstract Purpose To evaluate the long-term outcome and complications of trabeculectomy with β radiation. Design Retrospective noncomparative case series. Participants Forty-three patients with confirmed primary open-angle glaucoma (POAG), who received trabeculectomy with adjunctive β radiation at the Prince of Wales Hospital between June 1991 and November 1994. Methods Patients fulfilling the preceding criteria were followed up longitudinally. The visual acuity, intraocular pressure (IOP), bleb morphology, and complications were evaluated. Main outcome measures Visual acuity, IOP, bleb morphology, complications. Results Forty-three eyes of 43 consecutive Chinese patients were recruited and successfully followed up for a minimum of 7 years. The mean age ± 1 standard deviation (SD) was 60.9 ± 13.0 years. There were 29 males and 14 females. The mean baseline IOP ± 1 SD was 28.3 ± 5.8 mmHg. The mean postoperative IOP ± 1 SD after the initial trabeculectomy was 11.9 ± 4.3 mmHg, and the mean number of preoperative IOP-lowering eyedrops ± 1 SD was reduced from 2.8 ± 0.5 to 0.7 ± 1.0 at 7 years follow-up. The qualified success rate at 7 years follow-up, defined as IOP ≤21 mmHg with and without medication(s), was 88.4%. The complete success rate at 7 years defined as IOP ≤21 mmHg without medication was 60.7%. Two eyes developed blebitis, and one of them progressed to corneal decompensation after the infection. One eye had hypotony, and one eye had a traumatic ruptured bleb. Twelve eyes (27.9%) developed significant cataract. No corneal ulceration or scleral necrosis was encountered. Conclusions From this noncomparative study, trabeculectomy with a single dose of 1000 rad β radiation used as an adjunctive measure for POAG in Chinese eyes had achieved a qualified success rate of 88.4% at 7 years.

Physical effects of reuse and repeated ethylene oxide sterilization on transscleral cyclophotocoagulation laser G-probes

PurposeThe authors documented the physical effects of reuse and repeated ethylene oxide sterilization on transscleral cyclophotocoagulation laser G-probes. MethodsTransscleral cyclophotocoagulation was performed using G-probes on fresh porcine eyes. Each of two G-probes was used for four transscleral cyclophotocoagulation procedures, with three cycles of ethylene oxide sterilization in between. The power output from the G-probes was measured by a laser output meter before and after each transscleral cyclophotocoagulation procedure. The G-probes were also examined under a slit lamp for signs of physical damage. ResultsRepeated use of the G-probe in transscleral cyclophotocoagulation, with ethylene oxide sterilization in between, resulted in an average decrease of 3% in laser energy delivered per repeated cycle of use up to the fourth cycle. No signs of physical damage were found. ConclusionsLaser G-probes remain functional after repeated use and ethylene oxide resterilization for up to four cycles. No visible physical damage to the probes was identified. It is safe and cost-effective to reuse G-probe for transscleral cyclophotocoagulation with ethylene oxide sterilization, provided the surgeon stays alert for signs of probe damage. This alertness should be retained regardless of whether new or old G-probes are used.

Polyhexamethylene biguanide (0.02%) alone is not adequate for treating chronic Acanthameoba keratitis.

Polyhexamethylene biguanide (0.02%) alone is not adequate for treating chronic Acanthameoba keratitis

In Search of Excellence: From Radial Keratotomy to Laser-Assisted In Situ Keratomileusis

Since refractive surgery was started in Japan during the 1930s, there have been many developments and advances. We are still working, however, toward a more “perfect” procedure. The major difference between refractive surgery and other eye operations is that we are operating on eyes with normal vision. The demand for outcome predictability, stability of postoperative refraction, and operative safety is naturally high. Although radial keratotomy (RK) does not involve the central visual area of the cornea, the tissue damage incurred is substantial. Unpredictability about surface wound healing is the major problem associated with photorefractive keratoplasty (PRK). Neither PRK nor RK is a good choice for the high myopes. Although clear lens extraction with intraocular lens implantation can treat the severe high myopes, the risk of postoperative retinal detachment is not low. The intrastromal corneal ring is still in the investigational stage. The new procedure, laser-assisted in situ keratomileusis (LASIK) produces excellent results for the moderate and high myopia groups. Although there are problems at the interface, LASIK is undergoing active, rapid development. It is likely that LASIK will become state of the art and the gold standard for refractive surgery in future.