Elsevier

Ophthalmology

Volume 111, Issue 8, August 2004, Pages 1470-1474
Ophthalmology

Original article
Acute primary angle closure: Configuration of the drainage angle in the first year after laser peripheral iridotomy

https://doi.org/10.1016/j.ophtha.2004.01.036Get rights and content

Abstract

Purpose

To evaluate the changes in the configuration of the drainage angle in the first year after acute primary angle closure (APAC).

Design

Prospective observational case series.

Participants

Forty-four Asian subjects with APAC.

Methods

Acute primary angle closure cases were treated with medical therapy followed by laser peripheral iridotomy (LPI). Static and dynamic gonioscopies were performed in APAC-affected and fellow eyes before LPI (baseline) and then at 2 weeks, 4 months, and 12 months after presentation. The angles were graded in each quadrant according to the Shaffer scheme, and the number of clock hours of peripheral anterior synechiae (PAS) was recorded. Patients who underwent intraocular surgery at any point during follow-up were excluded from the study. Intraocular pressure (IOP) and medical treatment were documented at each visit, and gonioscopic changes were correlated with the development of elevation in IOP requiring medical treatment.

Main outcome measures

Average Shaffer grade and the number of clock hours of PAS.

Results

The majority of subjects were Chinese (84%) and female (64%), and the mean age was 60.2±10.7 years. At presentation, 73% of both affected and fellow eyes had very narrow angles (average Shaffer grade ≤ 1), with affected eyes having more extensive PAS (P<0.001), a third of whom had ≥8 clock hours of PAS. In APAC eyes, there was a significant increase in angle width from baseline to 2 weeks after LPI (P = 0.045), but no change in angle width subsequently. Fellow eyes showed a widening of the angle between baseline and week 2 (P = 0.01) and from week 2 to month 4 (P = 0.001). There was no significant change in PAS in either affected or fellow eyes over the 12 months of follow-up. Of the 44 subjects, 19 (41.3%) subsequently developed IOP elevation during follow-up that required treatment. However, there was no difference in angle width or amount of PAS between eyes with and without a subsequent rise in IOP, and the angle configuration did not change significantly in either group over 1 year.

Conclusion

In Asian eyes with APAC, the angle widened in the first 2 weeks after LPI, but did not change thereafter over 1 year, and the amount of PAS remained stable throughout. The results indicate the effectiveness of LPI in preventing progressive closure of the angle in the first year after APAC.

Section snippets

Materials and methods

Subjects with APAC who were 21 years or older were eligible for the study. Written informed consent was obtained from all subjects, and the study had the approval of the Ethics Committee of the Singapore National Eye Centre and was performed according to the tenets of the Declaration of Helsinki. Demographic characteristics and ophthalmic data related to the APAC episode (such as laterality of the affected eye, duration of acute symptoms, and presenting IOP) were recorded. Characteristics of

Results

A total of 44 APAC subjects completed the study. All subjects were of Asian origin, with the majority of Chinese (84%) ethnicity (Table 1). There were 29 females (64%), and the mean age was 60.2±10.7 years (range, 35–99). Disease presentation was unilateral in all cases, and the characteristics of the acute episode, such as presenting IOP, duration of symptoms, and the interval between presentation and LPI, are summarized in Table 2. Interobserver correlation between the 2 investigators

Discussion

Changes in angle configuration over time have previously been reported in a Mongolian population.13 A median increase of 2 Shaffer grades was documented after 1 to 3 years in eyes treated with LPI, and the number of quadrants affected by PAS was stable in 64%, decreased in 18.8%, and increased in 25%. However, the study population involved a mix of cases of asymptomatic narrow angles, primary angle closure, and primary angle glaucoma (defined according to the terminology proposed by Foster et al

References (22)

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    • Laser Peripheral Iridotomy in Primary Angle Closure: A Report by the American Academy of Ophthalmology

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      Six studies used both gonioscopy and imaging (UBM or ASOCT) to evaluate the angle. Of the 13 studies that used gonioscopy, 10 studies7,8,10,12,15–19,21 reported the change in angle width after LPI, 2 studies22,23 reported only the proportion of subjects with persistent ITC after LPI, and 1 study14 only commented on the change in PAS after LPI. All but 3 studies had subjects of Asian origin, including Chinese, Mongolian, Korean, Indian, and Vietnamese.

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