Elsevier

Ophthalmology

Volume 105, Issue 11, 1 November 1998, Pages 2091-2098
Ophthalmology

Ultrasound biomicroscopic and conventional ultrasonographic study of ocular dimensions in primary angle-closure glaucoma1

https://doi.org/10.1016/S0161-6420(98)91132-0Get rights and content

Abstract

Objective

To determine the biometric findings of ocular structures in primary angle-closure glaucoma (PACG).

Design

An observational case series with comparisons among three groups (patients with acute/intermittent PACG [A/I-PACG], patients with chronic PACG [C-PACG], and normal subjects [N]).

Participants

A total of 54 white patients with PACG (13 male, 41 female) were studied: 10 with acute, 22 with intermittent, and 22 with chronic types of PACG. Forty-two normal white subjects (11 male, 31 female) were studied as control subjects. Only one eye was considered in each patient or subject.

Testing

Ultrasound biomicroscopy (UBM) and standardized A-scan ultrasonography (immersion technique) were performed in each patient during the same session or within 1 to 3 days.

Main outcome measures

The following A-scan parameters were measured: anterior chamber depth (ACD), lens thickness (LT), axial length (AL), lens/axial length factor (LAF), and relative lens position (RLP). Ten UBM parameters were measured, the most important of which were anterior chamber angle, trabecular-ciliary process distance (TCPD), angle opening distance at 500 μm from the scleral spur (AOD 500), and scleral-ciliary process angle (SCPA).

Results

Compared to normal subjects, the patients with PACG presented a shorter AL (A/I-PACG = 22.31 ± 0.83 mm, C-PACG = 22.27 ± 0.94 mm, N = 23.38 ± 1.23 mm), a shallower ACD (A/I-PACG = 2.41 ± 0.25 mm, C-PACG = 2.77 ± 0.31 mm, N = 3.33 ± 0.31 mm), a thicker lens (A/I-PACG = 5.10 ± 0.33 mm, C-PACG = 4.92 ± 0.27 mm, N = 4.60 ± 0.53 mm), and a more anteriorly located lens (RLP values, A/I-PACG = 2.22 ± 0.12, C-PACG = 2.34 ± 0.16, N = 2.41 ± 0.15). The LAF values in A/I-PACG, C-PACG, and N were 2.28 ± 012, 2.20 ± 0.11, and 1.97 ± 0.12, respectively. Anterior chamber angle (A/I-PACG = 11.72 ± 8.84, C-PACG = 19.87 ± 9.83, N = 31.29 ± 9.18°) and SCPA (A/I-PACG = 28.71 ± 4.02, C-PACG = 30.87 ± 6.04, N = 53.13 ± 9.58°) were narrower, TCPD (A/I-PACG = 0.61 ± 0.12 mm, C-PACG = 0.71 ± 0.14 mm, N = 1.08 ± 0.22 mm) and AOD 500 shorter (A/I-PACG = 0.13 ± 0.09 mm, C-PACG = 0.21 ± 0.10 mm, N = 0.36 ± 0.11 mm) in patients with PACG. All the biometric differences proved statistically significant using the one-way analysis-of-variance test.

Conclusions

In patients with PACG, the anterior segment is more crowded because of the presence of a thicker, more anteriorly located lens. The UBM confirms this crowding of the anterior segment, showing the forward rotation of the ciliary processes. A gradual progressive shift in anatomic characteristics is discernible on passing from normal to chronic PACG and then to acute/intermittent PACG eyes.

Section snippets

Patients

A total of 54 eyes of 54 white patients with angle closure glaucoma (ACG) were considered in this study. Special types of ACG, such as “plateau iris” and spherophakia, and secondary ACG (lens intumescence or subluxation, trauma, iris neovascularization) were specifically excluded. The clinical case material comprised 10 acute, 22 intermittent, and 22 patients with chronic PACG 64 years of age ± 8 years (range, 43–78 years). The male-to-female ratio was 13:41 (76% women). The diagnosis was based

Conventional A-scan ultrasonography

The results of the A-scan biometric study are given in Table 2. In patients with PACG, the axial length was significantly shorter, the anterior chamber shallower, and the lens thicker and more anteriorly located than in normal individuals. The LAF of patients with PACG was significantly greater than in normal subjects.

In patients with PACG, there was no difference in axial length between the acute/intermittent and the chronic cases. The eyes with acute/intermittent PACG, however, were

Conventional A-scan ultrasonography

The biometric features encountered in our series of patients with PACG are no different from those widely reported in white subjects.1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 Compared to normal eyes, the PACG eyes examined in our study were characterized on the whole by a shorter axial length, a distinctly shallower anterior chamber, a thicker lens, and, as indicated by the RLP, a more anteriorly situated lens. This results in a higher LAF with a difference compared to normal that

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