Elsevier

Ophthalmology

Volume 117, Issue 4, April 2010, Pages 700-704
Ophthalmology

Original article
Central Corneal Thickness in Adult South Indians: The Chennai Glaucoma Study

https://doi.org/10.1016/j.ophtha.2009.09.025Get rights and content

Objective

To evaluate the characteristics of central corneal thickness (CCT) and its association with age, gender, and intraocular pressure in rural and urban South Indian populations.

Design

Population-based cross-sectional study.

Participants

Seven thousand seven hundred seventy-four subjects (rural-to-urban ratio, 3924:3850) aged 40 years and older were examined at a dedicated facility in the base hospital.

Intervention

All subjects underwent a complete ophthalmic examination that included CCT measurements with an ultrasonic pachymeter and applanation tonometry.

Main Outcome Measures

Central corneal thickness.

Results

Of the 7774 subjects examined, 974 had undergone cataract surgery and were excluded. The remaining 6800 were bilaterally phakic, of which 46 were excluded (17 glaucoma subjects receiving treatment, 12 with corneal pathologic features and 17 with incomplete data) and 6754 subjects data were analyzed. The mean CCT for the population was 511.4±33.5 μm, and CCT in males (515.6±33.8 μm) was significantly (P = 0.0001) greater than females (508.0±32.8 μm). The CCT was significantly greater (by 18 μm) in the urban population and decreased with age in both genders (P<0.0001). The decrease per decade was 4.34 μm (95% confidence interval [CI], 3.24–5.44) in the rural population and 2.41 μm (95% CI, 1.25–3.53) in the urban population. A 100-μm increase in CCT was associated with a 1.96-mmHg increase in intraocular pressure in the rural population, versus 2.45 mmHg for every 100 μm in the urban population.

Conclusions

In this population-based study, females and subjects living in a rural area had thinner corneas. A negative association with age and a positive association with intraocular pressure were seen. These findings will have implications in the diagnosis and management of glaucoma in this population.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found after the references.

Section snippets

Methods

This study was approved by the institutional ethics review board. The methods and design of the Chennai Glaucoma Study are described in detail elsewhere.19 Briefly, the Chennai Glaucoma Study was designed to estimate the prevalence of glaucoma. A sample size of 4758 was arrived at assuming an 85% response rate for an assumed 3% population prevalence of glaucoma with a relative precision of 25% and a design effect of 2. Therefore, 4800 subjects each from the rural and urban populations were

Study Cohort

Nine thousand six hundred subjects were enumerated. Of them 7774 subjects (rural-to-urban ratio, 3924:3850) participated in the study. There was no difference between the urban and the rural groups in terms of gender distribution and participation and nonparticipation rates. However, the urban population was significantly older than the rural population, both among the participants (54.8±10.6 years vs. 53.8±10.6 years; P<0.0001) and nonparticipants (53.8±10.9 years vs. 52.5±10.5 years; P<0.008).

Discussion

This study reports the distribution and factors associated with CCT among individuals from a rural and an urban south Indian population. To the best of the authors' knowledge, this is the first population-based report of its kind from India. These findings suggest that females tend to have thinner corneas. Central corneal thickness negatively correlated with increasing age and positively with intraocular pressure. Past studies have shown there are ethnicity-related differences in the average

References (24)

  • N. Ehlers et al.

    Applanation tonometry and central corneal thickness

    Acta Ophthalmol (Copenh)

    (1975)
  • L.W. Herndon et al.

    Central corneal thickness in normal, glaucomatous, and ocular hypertensive eyes

    Arch Ophthalmol

    (1997)
  • Cited by (0)

    Manuscript no. 2009-374.

    Financial Disclosure(s): The author(s) have made the following disclosure(s):

    Lingam Vijaya - Lecturer - Alcon, Pfizer, and Allergan.

    Ronnie George - lecturer - Carl Zeiss, Pfizer, and Allergan.

    Supported by the Chennai Willingdon Corporate Foundation, Chennai, India.

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