Original Article
Limbus-insertion distance of superior rectus in primary angle closure glaucoma: an anterior segment OCT study

https://doi.org/10.1016/j.jcjo.2016.06.003Get rights and content

Abstract

Objective

To compare the distance from the corneoscleral limbus to the insertion site of the superior rectus of primary angle-closure glaucoma (PACG) patients with normal controls and to identify potential characteristics associated with limbus-insertion distance.

Design

Cross-sectional study.

Participants

A total of 92 subjects (eyes) were enrolled in the study: 35 were nonglaucoma controls and 57 were PACG patients.

Methods

The limbus-insertion distance of the superior rectus was measured by anterior segment optical coherence tomography (AS-OCT) and intraoperative surgical caliper. The anterior chamber parameters were also measured using AS-OCT to identify potential characteristics associated with limbus-insertion distance.

Results

The limbus-insertion distance of the superior rectus was 0.40 ± 0.08 mm shorter in the PACG group than in the normal control group (p < 0.001). Anterior segment parameter values, including anterior chamber depth (ACD), anterior chamber width (ACW), anterior chamber area (ACA), and anterior chamber volume (ACV), were smaller in the PACG group than in the normal control group, but the lens vault was larger (all p < 0.001). A shorter limbus-insertion distance of the superior rectus was significantly associated with shorter axial length and “crowded” angle (smaller ACD, ACW, ACA, and ACV) (all p < 0.05).

Conclusions

This is the first study to demonstrate that the limbus-insertion distance of the superior rectus was shorter in PACG eyes than in normal eyes. The shorter limbus-insertion distance may be another anatomic characteristic of PACG eyes.

RÉSUMÉ

Objectif

Comparer la distance entre le limbe sclérocornéen et le site d'insertion du muscle droit supérieur chez des patients atteints de glaucome primitif par fermeture de l'angle (GPFA) et chez un groupe contrôle normal; définir les caractéristiques potentielles associées à la distance limbe-insertion.

Nature

Étude transversale.

Participants

L'étude a porté sur 92 sujets (yeux) : 35 faisaient partie du groupe témoin normal et 57 étaient des patients atteints de GPFA.

Méthodes

La distance limbe-insertion du muscle droit supérieur a été mesurée par tomographie par cohérence optique du segment antérieur (TCO-SA) et avec un compas peropératoire. Les paramètres de la chambre antérieure ont également été mesurés par TCO-SA pour identifier les caractéristiques potentielles associées à la distance limbe-insertion.

Résultats

La distance entre le limbe et le point d'insertion du muscle droit supérieur était plus courte de 0,40 ± 0,08 mm chez les patients du groupe GPFA que chez ceux du groupe témoin normal (p < 0,001). Les paramètres du segment antérieur, notamment la profondeur de la chambre antérieure (PCA), la largeur de la chambre antérieure (LCA), la surface de la chambre antérieure (SCA) et le volume de la chambre antérieure (VCA), étaient également inférieurs chez les patients du groupe GPFA à ceux du groupe témoin, mais la flèche cristallinienne était plus grande (toutes p < 0,001). Une distance limbe-insertion du muscle droit supérieur plus courte était significativement associée à une longueur axiale plus courte et à un angle congestionné (PCA, LCA, SCA et VCA plus petits) (toutes p < 0,05).

Conclusions

Cette étude est la première à démontrer que la distance limbe-insertion du muscle droit supérieur est plus courte dans les yeux de patients atteints de GPFA que dans des yeux normaux. Une distance limbe-insertion plus courte pourrait être une autre caractéristique anatomique des yeux atteints de GPFA.

Section snippets

Subject Recruitment

All participants received a detailed explanation about the study and signed an informed consent form in accordance with the principles embodied in the Declaration of Helsinki. This study was approved by the Ethics Review Committee of Zhongshan Ophthalmic Center. Participants were recruited prospectively and consecutively for this study, between April 2013 and July 2013. All subjects were from a Chinese Han population.

Participants were selected as a representative sample of patients and age- and

Results

A total of 92 subjects (eyes) were enrolled in the study: 35 were nonglaucoma controls and 57 were PACG patients. The demographic and clinical data of the 2 groups are summarized in Table 1. The mean age of the PACG patients and the normal control individuals was 60.8 ± 8.7 and 58.7 ± 15.7 years, respectively (p = 0.473). No significant difference was noted in sex distribution between the 2 groups. As would be expected, AL was significantly longer in normal eyes than in the PACG group (p <

Discussion

The intraoperative surgical caliper measurement was considered the gold standard because it provides a direct view and measurement. The correlation determined in this study between AS-OCT and surgical caliper measurements was considered good. This result matches the strong correlations found in a previous study.14 AS-OCT provides a good image of the structure of the superior rectus muscles with satisfactory reliability and accuracy. In the present study, the mean limbus-insertion distance of

Conclusions

We found that AS-OCT can provide a good image of the structure of the superior rectus muscles with satisfactory accuracy for the measurement of the limbus-insertion distance. The limbus-insertion distance of the superior rectus was shorter in PACG eyes than in normal eyes. Shorter limbus-insertion distance of the superior rectus was significantly associated with shorter AL and “crowded” angle (smaller ACD, ACW, ACA, and ACV). Thus, a shorter limbus-insertion distance may be another anatomic

Disclosure

The authors have no proprietary or commercial interest in any materials discussed in this article.

Acknowledgements

This work was supported in whole or in part by the National Natural Science Foundation of China (81371008, 81200670), and the Science and Technology Planning Project of Guangdong Province, China (No. 2012B031800353).

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