Anterior Segment Dimensions Following Laser Iridotomy in Acute Primary Angle Closure and Fellow Eyes

doi:10.1016/j.ajo.2017.11.013

American Journal of Ophthalmology

Volume 186, February 2018, Pages 59-68

https://doi.org/10.1016/j.ajo.2017.11.013 Get rights and content

Purpose

To compare the change in anterior segment morphology after laser peripheral iridotomy (LPI) in acute primary angle closure (APAC) and their fellow eyes.

Design

Prospective, fellow eye–matched case series.

Methods

In this study 42 individuals with unilateral episode of APAC were enrolled and the anterior segment optical coherence tomography (ASOCT) images were obtained in both eyes at baseline and at 6 weeks after LPI. A linear mixed-effects model was used to compare changes in anterior chamber and angle variables with consideration of laterality as the random effect and pupil diameter as the fixed effect.

Results

APAC eyes had smaller angle parameters (P = .013 for all), less central anterior chamber depth (cACD) (P < .001), and lower anterior chamber area (ACA) (P < .001), as well as greater lens vault (LV) (P = .007), compared with fellow eyes. LPI resulted in angle widening with a significant increase in opening distance (P < .01 for all) in both APAC and fellow eyes. cACD (P = .003) and ACA (P < .001) increased and LV (P = .002) decreased in APAC eyes. However, there was no significant change in cACD (P = .190) and LV (P = .430) in fellow eyes. In both APAC eyes and fellow eyes, iris curvature decreased after LPI (P < .001). The changes in angle parameters, ACA, and iris curvature were not significantly different between the 2 groups.

Conclusion

In APAC eyes and their fellow eyes, LPI resulted in significant anterior chamber angle widening and increased anterior chamber area. In APAC eyes, the iris flattened, cACD deepened, and the lens shifted posteriorly after resolution of the attack. However, in fellow eyes, the increase in ACA was mainly owing to decreased iris curvature.

Section snippets

Methods

In this prospective, fellow eye–matched case series, subjects with acute primary angle closure were recruited consecutively from the glaucoma clinic of Farabi Eye Hospital, Tehran, Iran, from January 2011 to January 2014. The study protocol was approved by the institutional review board of the hospital and followed the tenets of the Declaration of Helsinki. Written informed consent was obtained from all patients.

All patients had an APAC attack, defined by the presence of the following: (1) at

Results

A total of 54 subjects with successfully treated APAC were recruited for the study. After exclusion of patients with prior cataract surgery in the fellow eye (1 patient), poor-quality AS-OCT images with indeterminate scleral spurs or inability to assess parameters adequately with the ZAAP software (6 patients), loss to follow-up (3 patients), and uncontrolled IOP requiring phacoemulsification (2 patients), data from 42 APAC eyes were used for comparison with their fellow eyes.

Of these 42

Discussion

The anatomic and nonanatomic factors related to APAC and the effect of LPI on APAC eyes are not well understood. We compared the effect of LPI on anterior segment parameters of APAC and fellow eyes using AS-OCT and found that all angle parameters deepened and iris flattened in both APAC and fellow eyes after LPI. Although anterior chamber area increased after LPI in both groups, cACD increased and LV decreased only in APAC eyes.

In the fellow eyes, it was observed that LPI leads to a significant

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The crystalline lens plays an important role in the pathophysiology of primary angle closure and primary angle-closure glaucoma. The aging process is associated with a progressive enlargement of the lens, resulting in greater iridolenticular and iridotrabecular contact, which exacerbates both pupillary block and appositional angle closure, irrespective of the cataract status of the lens. Cataract surgery has been shown to widen the angle and reduce intraocular pressure in eyes with primary angle closure or primary angle-closure glaucoma. Recently, clear lens phacoemulsification has been suggested as a treatment modality in such eyes. We review the literature on clear lens extraction in eyes with angle closure and discuss its efficacy, safety, and indications. Although it is evident that clear lens extraction is beneficial in eyes with primary angle closure and primary angle-closure glaucoma, it is technically challenging and should be performed by experienced surgeons who not only master the procedure but are also able to deal with potential complications. Since the follow-up of the reviewed studies is relatively short, long-term follow-up (>10 years) of patients who undergo this procedure is needed to evaluate the safety and confirm the early benefits reported.
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Retrospective review.
A total of 1271 eyes in 692 subjects with narrow angles (NAs) that were treated with LPI.
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The primary angle-closure disease spectrum varies from a narrow angle to advanced glaucoma. A variety of imaging technologies may assist the clinician in determining the pathophysiology and diagnosis of primary angle closure, but gonioscopy remains a mainstay of clinical evaluation. Laser iridotomy effectively eliminates the pupillary block component of angle closure; however, studies show that, in many patients, the iridocorneal angle remains narrow from underlying anatomic issues, and increasing lens size often leads to further narrowing over time. Recent studies have further characterized the role of the lens in angle-closure disease, and cataract or clear lens extraction is increasingly used earlier in its management. As a first surgical step in angle-closure glaucoma, lens extraction alone often effectively controls the pressure with less risk of complications than concurrent or stand-alone glaucoma surgery, but may not be sufficient in more advanced or severe disease. We provide a comprehensive review on the primary angle-closure disease nomenclature, imaging, and current laser and surgical management.
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Original articleAnterior Segment Dimensions Following Laser Iridotomy in Acute Primary Angle Closure and Fellow Eyes

Purpose

Design

Methods

Results

Conclusion

Section snippets

Methods

Results

Discussion

Ophthalmology

Ophthalmology

Am J Ophthalmol

J Curr Ophthalmol

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Am J Ophthalmol

The number of people with glaucoma worldwide in 2010 and 2020

Br J Ophthalmol

Acute angle-closure glaucoma: the second eye: an analysis of 200 cases

Br J Ophthalmol

Anterior segment optical coherence tomography parameters in subtypes of primary angle closure

Invest Ophthalmol Vis Sci

Ocular biometry in the subtypes of angle closure: an anterior segment optical coherence tomography study

Am J Ophthalmol

Appositional angle closure in eyes with narrow angles: comparison between the fellow eyes of acute angle-closure glaucoma and normotensive cases

J Glaucoma

Anterior segment optical coherence tomography parameters in phacomorphic angle closure and mature cataracts

Invest Ophthalmol Vis Sci

Original article
Anterior Segment Dimensions Following Laser Iridotomy in Acute Primary Angle Closure and Fellow Eyes