Elsevier

Ophthalmology

Volume 115, Issue 9, September 2008, Pages 1545-1549
Ophthalmology

Original article
The Heritability of Corneal Hysteresis and Ocular Pulse Amplitude: A Twin Study

https://doi.org/10.1016/j.ophtha.2008.02.011Get rights and content

Purpose

To examine the roles of genetic and environmental factors in corneal hysteresis and ocular pulse amplitude by performing a classic twin study.

Design

Cross-sectional twin study.

Participants and/or Controls

Two hundred sixty-four twin pairs: 135 monozygotic (MZ) and 129 dizygotic (DZ).

Methods

Corneal hysteresis was measured using the Reichert Ocular Response Analyzer (ORA; Reichert, Buffalo, NY), and ocular pulse amplitude was measured using the Pascal Dynamic Contour Tonometer (DCT; Swiss Microtechnology AG, Port, Switzerland).

Main Outcome Measures

Contribution of genetic and environmental effects on corneal hysteresis and OPA among MZ and DZ twins.

Results

The mean corneal hysteresis was10.24±1.54 mmHg and the mean ocular pulse amplitude was 2.88±0.97 mmHg. The MZ correlations were higher than DZ for both corneal hysteresis and ocular pulse amplitude (correlation coefficients, 0.75:0.42 and 0.59:0.32 for MZ:DZ twins, respectively). Modeling suggested heritability of corneal hysteresis of 0.77 (95% confidence interval [CI], 0.70–0.82), with the remaining proportion of variance because of individual environmental effects of 0.23 (95% CI, 0.18–0.30). For ocular pulse amplitude, the heritability was 0.62 (95% CI, 0.51–0.70), with the remaining proportion of variance the result of individual environmental effects of 0.38 (95% CI, 0.30–0.49).

Conclusions

This study demonstrated that additive genetic influences explained most of the individual differences in corneal hysteresis and ocular pulse amplitude among these twins.

Financial Disclosure(s)

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

Section snippets

Patients and Methods

Two hundred seventy-two pairs of healthy twins, mean age of 54.1 years (range, 16–78 years), were recruited from the TwinsUK Adult Twin Registry, held at St. Thomas' Hospital, London. They were unaware of any hypotheses or proposals for specific studies; only later were they invited to have an eye examination. The institutional ethics committee approved the study, and all the patients gave informed consent. Zygosity was determined by a standardized questionnaire16 and was confirmed by DNA

Results

Of the original 272 pairs of twins recruited, 8 pairs were excluded: 5 pairs because one or both twins had undergone excimer laser refractive surgery and the other 3 pairs because one of each pair could not undergo the tests. Thus, 264 twin pairs (135 MZ, 129 DZ) were included in the analysis; all were white and 92.5% were female. The overall mean of all 4 corneal hysteresis readings for each individual was10.24±1.54 mmHg. Corneal hysteresis measurements for right and left eyes correlated

Discussion

The authors demonstrated that both ocular pulse amplitude and corneal hysteresis, which play a role in glaucoma and IOP,6, 17 are strongly influenced by genes. Despite a similar distribution of CCT in an Asian population, tonometric measurement of cannulated Asian eyes revealed lower applanation IOP readings compared with that of Europeans.6 One possible explanation is that eyes with the same CCT may differ in elastic responsiveness (corneal hysteresis) because of ethnic variation, and this may

References (35)

  • L.W. Herndon

    Measuring intraocular pressure-adjustments for corneal thickness and new technologies

    Curr Opin Ophthalmol

    (2006)
  • N. Ehlers et al.

    Applanation tonometry and central corneal thickness

    Acta Ophthalmol (Copenh)

    (1975)
  • M.O. Gordon et al.

    The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma

    Arch Ophthalmol

    (2002)
  • O.S. Punjabi et al.

    Dynamic contour tonometry: principle and use

    Clin Experiment Ophthalmol

    (2006)
  • G.T. Georgopoulos et al.

    The short-term effect of latanoprost on intraocular pressure and pulsatile ocular blood flow

    Acta Ophthalmol Scand

    (2002)
  • K.G. Schmidt et al.

    Ocular pulse amplitude is reduced in patients with advanced retinitis pigmentosa

    Br J Ophthalmol

    (2001)
  • O. Schwenn et al.

    Ocular pulse amplitude in patients with open angle glaucoma, normal tension glaucoma, and ocular hypertension

    Br J Ophthalmol

    (2002)
  • Cited by (55)

    • Heritability of glaucoma and glaucoma-related endophenotypes: Systematic review and meta-analysis

      2019, Survey of Ophthalmology
      Citation Excerpt :

      The most commonly reported endophenotypes were IOP (n = 41), ACS (n = 26), CCT (n = 15), and CDR (n = 11) (Supplementary Table S5). Conversely, there was only one h2 estimate reported for the following endophenotypes: iris thickness,48 ocular pulse amplitude,19 pulsatility of blood flow,39 and ganglion cell complex thickness.14 Using the CCT cluster as an example, the pooled h2 is depicted in a forest plot (Fig. 3).

    • Corneal hysteresis: Ready for prime time?

      2022, Current Opinion in Ophthalmology
    View all citing articles on Scopus

    Manuscript no. 2007-1383.

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

    Supported by a grant from The Guide Dogs for The Blind Association, Berkshire, United Kingdom.

    View full text