Determinants and Two-Year Change in Anterior Chamber Angle Width in a Chinese Population

doi:10.1016/j.ophtha.2012.06.051

Ophthalmology

Volume 119, Issue 12, December 2012, Pages 2500-2506

https://doi.org/10.1016/j.ophtha.2012.06.051 Get rights and content

Objective

To study the population distribution and longitudinal changes in anterior chamber angle width and its determinants among Chinese adults.

Design

Prospective cohort, population-based study.

Participants

Persons aged 35 years or more residing in Guangzhou, China, who had not previously undergone incisional or laser eye surgery.

Methods

In December 2008 and December 2010, all subjects underwent automated keratometry, and a random 50% sample had anterior segment optical coherence tomography with measurement of angle-opening distance at 500 μm (AOD500), angle recess area (ARA), iris thickness at 750 μm (IT750), iris curvature, pupil diameter, corneal thickness, anterior chamber width (ACW), lens vault (LV), and lens thickness (LT) and measurement of axial length (AL) and anterior chamber depth (ACD) by partial coherence laser interferometry.

Main Outcome Measures

Baseline and 2-year change in AOD500 and ARA in the right eye.

Results

A total of 745 subjects were present for full biometric testing in both 2008 and 2010 (mean age at baseline, 52.2 years; standard deviation [SD], 11.5 years; 53.7% were female). Test completion rates in 2010 varied from 77.3% (AOD500: 576/745) to 100% (AL). Mean AOD500 decreased from 0.25 mm (SD, 0.13 mm) in 2008 to 0.21 mm (SD, 13 mm) in 2010 (difference, −0.04; 95% confidence interval [CI], −0.05 to −0.03). The ARA decreased from 21.5±3.73 10⁻² mm² to 21.0±3.64 10⁻² mm² (difference, −0.46; 95% CI, −0.52 to −0.41). The decrease in both was most pronounced among younger subjects and those with baseline AOD500 in the widest quartile at baseline. The following baseline variables were significantly associated with a greater 2-year decrease in both AOD500 and ARA: deeper ACD, steeper iris curvature, smaller LV, greater ARA, and greater AOD500. By using simple regression models, we could explain 52% to 58% and 93% of variation in baseline AOD500 and ARA, respectively, but only 27% and 16% of variation in 2-year change in AOD500 and ARA, respectively.

Conclusions

Younger persons and those with the least crowded anterior chambers at baseline have the largest 2-year decreases in AOD500 and ARA. The ability to predict change in angle width based on demographic and biometric factors is relatively poor, which may have implications for screening.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Materials and Methods

Random cluster sampling was used to identify adults aged ≥35 years resident in the Yuexiu District of Guangzhou, China, for participation in a study of presbyopia in December 2008. Details of the recruitment and examination procedures have been reported⁹ and are summarized in this article for reference. During door-to-door household visits, data on all persons aged ≥35 years were collected, including name, sex, and age. Examinations including measurement of binocular near visual acuity,

Results

A total of 745 persons underwent biometric testing in both 2008 and 2010. Subjects not present for testing in 2010 did not differ from those available for testing with regard to baseline age in 2008, sex, weight, height, spectacle wear, or any of the measured ocular biometric parameters (right eye ACD, AL, IT750, corneal thickness, corneal curvature, iris curvature, lens thickness, AOD500, LV, pupil size, or ACW) (Table 1, available at http://aaojournal.org). The number of subjects successfully

Discussion

This is the first population-based, longitudinal study of quantitative measures of anterior chamber angle width in Chinese persons, who have a high prevalence of primary angle-closure diseases.14, 15 We found that persons with younger age at baseline and biometric characteristics of a less-crowded angle were generally at risk for greater 2-year decreases in angle width as measured by AOD500 and ARA. A recent cross-sectional study in Singapore analyzed similar quantitative angle measures in a

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Participants underwent AS-OCT, posterior segment OCT, and intraocular pressure (IOP) testing in the community. Those meeting referral criteria in either eye were invited to have a comprehensive eye examination including gonioscopy. Referral criteria included (i) the lowest 2.5% of AS-OCT measurements, (ii) retinal OCT results suggestive of glaucomatous optic neuropathy, diabetic retinopathy, or age-related macular degeneration, and (iii) elevated IOP.
Sensitivity and specificity of 5 semiautomated AS-OCT parameters relative to gonioscopically narrow angles, defined as the absence of visible trabecular meshwork for ≥ 180° on nonindentation gonioscopy.
Of 17 656 people aged ≥ 60 years enumerated from 102 communities, 12 633 (71.6%) presented for AS-OCT testing. Referral was recommended for 697 participants based on AS-OCT criteria and 2419 participants based on other criteria, of which 858 had gonioscopy performed by a glaucoma specialist. Each of the 5 AS-OCT parameters offered good diagnostic information for predicting eyes with gonioscopically narrow angles, with areas under the receiver operating characteristic curve ranging from 0.85 to 0.89. The angle opening distance at 750 μm from the scleral spur (AOD750) provided the most diagnostic information, providing an optimal sensitivity of 87% (95% confidence interval [CI], 75%–96%) and specificity of 77% (71%–83%) at a cutpoint of 367 μm, and a sensitivity of 65% (95% CI, 54%–74%) when specificity was constrained to 90% (cutpoint, 283 μm).
On AS-OCT, the AOD750 parameter detected approximately two-thirds of cases of gonioscopically narrow angles when test specificity was set to 90%. Although such a sensitivity may not be sufficient when screening solely for narrow angles, AS-OCT requires little additional effort if posterior segment OCT is already being performed and thus could provide incremental benefit when performing OCT-based screening.
The authors have no proprietary or commercial interest in any materials discussed in this article.
Anterior chamber depth and angle and associations in a pediatric and adult population in Russia
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To investigate the normative data of anterior chamber depth (ACD) and angle (ACA) and their associations in multiethnic cohorts spanning three generations in Russia.
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The study included 4869 (98.7 %) children out of 4933 children of the UCES, 5426 (92.0 %) out of 5899 UEMS participants, and 268 (16.3 %) out of 1526 UVOS participants. In the UEMS, shallower ACD (mean:3.14 ± 0.37 mm) correlated (multivariable analysis; r[2] = 0.57) with older age (beta: 0.08;P < 0.001), shorter body height (beta:0.03;P = 0.003), shorter axial length (beta:0.34;P < 0.001), lower corneal volume (beta:0.06;P < 0.001) and corneal refractive power (beta:0.12;P < 0.001), thicker lens (beta: 0.09;P < 0.001), higher IOP (beta: 0.03;P = 0.02), higher prevalence of angle-closure glaucoma (beta: 0.03;P = 0.003) and lower prevalence of open-angle glaucoma (beta:0.03;P = 0.007). Similar associations were found in the UCES (ACD mean:3.70 ± 0.27 mm) and UVOS (ACD mean:2.96 ± 0.56 mm).
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Citation Excerpt :
It has been recognized greater LV as an anatomic parameter that is independently associated with angle closure.6 There are many studies in the literature that have reported LV and CLR data for different patient cohorts and making use of various measuring instruments.4–31 Some of these studies also measured, in the same series, other parameters such as anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white distance (WTW), central corneal thickness (CCT), anterior chamber volume (ACV) or spur-to-spur distance (STS).
To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT).
We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ± 12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance.
Mean LV was 0.26 ± 0.23 mm (ranging from -0.24 to 0.78 mm). Data analysis revealed a statistically significant negative correlation between LV and ACD (R=-0.80, p < 0.001), AL (R = -0.36, p = 0.002), and ACV (R = -0.68, p < 0.001), and a positive correlation between LV and LT (R = 0.67, p < 0.001), and age (R = 0.53, p < 0.001). In contrast, no statistically significant correlation was found between LV and WTW (R=-0.17, p = 0.15), CCT (R = 0.11, p = 0.36) or STS (R=-0.10, p = 0.41).
Taking into account our findings about intra-parameter correlation levels, we believe that LV should be measured and analyzed together with other ocular parameters in clinical routine practice both for diagnosis and for some refractive surgeries.
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Participants were identified using random cluster sampling from adults aged ≥35 years in the urban upper-middle-income Yuexiu District of Guangzhou, China, during the latter part of 2008. Details of the recruitment and study methodology have been reported elsewhere.15,19,20 In brief, 2284 eligible persons were enumerated during door-to-door household visits, including name, gender, and age; the study population for this article consists of the 1817 (79.6%) participants who attended baseline examinations.
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Among the 1817 baseline participants, 1595 (87.8%) were reexamined in 2010 and 1427 (78.5%) in 2014. Mean vision loss between baseline and the 2014 follow-up was 1.54 (±1.74) lines of UCNVA. Vision loss was associated with age 80 years or older, less education, and better baseline UCNVA. The 6-year cumulative incidence of uncorrected binocular NVI (UCNVI) across the 3 vision impairment definitions was 55.2% (95% confidence interval [CI], 46.1%–64.3%), 51.3% (95% CI, 44.0%–58.7%), and 42.4% (95% CI, 35.5%–49.3%), respectively. With best-corrected binocular NVI (BCNVI), incidence was 6.89% (95% CI, 4.28%–9.50%), 5.17% (95% CI, 2.89%–7.44%), and 2.62% (95% CI, 1.11%–4.12%), respectively. A higher incidence of UCNVI was associated with worse baseline UCNVA for all 3 impairment definitions. Similarly, incidence of BCNVI was associated with worse baseline BCNVA, but also with older age and education at the primary level or less. Gender was not significant for either UCNVI or BCNVI.
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: Manuscript no. 2012-420.

: Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

: Supported by the World Health Organization, Geneva, Switzerland (under National Institutes of Health [Bethesda, MD] contract number N01-EY-2103) and the Fundamental Research Funds for the State Key Laboratory.

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Original articleDeterminants and Two-Year Change in Anterior Chamber Angle Width in a Chinese Population

Objective

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Financial Disclosure(s)

Section snippets

Materials and Methods

Results

Discussion

Ophthalmology

Ophthalmology

Am J Ophthalmol

Ophthalmology

Surv Ophthlamol

J Cataract Refract Surg

The number of people with glaucoma worldwide in 2010 and 2020

Br J Ophthalmol

Glaucoma in China: how big is the problem?

Br J Ophthalmol

Screening for narrow angles in the Singapore population: evaluation of new noncontact screening methods

Ophthalmology

Diagnostic performance of anterior chamber angle measurements for detecting eyes with narrow angles: an anterior segment OCT study

Arch Ophthalmol

Variations in ocular biometry in an adult Chinese population: the Tanjong Pagar Survey

Invest Ophthalmol Vis Sci

Original article
Determinants and Two-Year Change in Anterior Chamber Angle Width in a Chinese Population