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The shape of the anterior and posterior surface of the aging human cornea.
Vision Res. 2006 Mar; 46(6-7):993-1001.VR

Abstract

PURPOSE

To determine the shape and astigmatism of the posterior corneal surface in a healthy population with age, using Scheimpflug photography corrected for distortion due to the geometry of the Scheimpflug imaging system and the refraction of the anterior corneal surface.

METHODS

Scheimpflug imaging was used to measure in six meridians the cornea of the right eye of 114 subjects, ranging in age from 18 to 65 years.

RESULTS

The average radius of the anterior corneal surface was 7.79+/-0.27 (SD) mm and the average radius of the posterior corneal surface was 6.53+/-0.25 (SD) mm. Both surfaces were found to be flatter horizontally than vertically. The cylindrical component of the posterior surface of 0.33 mm is twice that of the anterior surface (0.16 mm). The asphericity of both the anterior and the posterior surface was independent of the radius of curvature at the vertex, refractive error and gender. In contrast with that of the anterior corneal surface, the asphericity of the posterior corneal surface varied significantly between meridians. With age, the asphericity of both the anterior and the posterior corneal surface changes significantly, which results in a slight peripheral thinning of the cornea.

CONCLUSION

On average, the astigmatism of the posterior corneal surface (-0.305 D) compensates the astigmatism of the anterior corneal surface (0.99 D) with 31%. The results show that the effective refractive index is 1.329, which is lower than values commonly used. There is no correlation between the asphericity of the anterior and the posterior corneal surface. As a result, the shape of the anterior corneal surface provides no definitive basis for knowing the asphericity of the posterior surface.

Authors+Show Affiliations

Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands. m.dubbelman@vumc.nlNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16266736

Citation

Dubbelman, M, et al. "The Shape of the Anterior and Posterior Surface of the Aging Human Cornea." Vision Research, vol. 46, no. 6-7, 2006, pp. 993-1001.
Dubbelman M, Sicam VA, Van der Heijde GL. The shape of the anterior and posterior surface of the aging human cornea. Vision Res. 2006;46(6-7):993-1001.
Dubbelman, M., Sicam, V. A., & Van der Heijde, G. L. (2006). The shape of the anterior and posterior surface of the aging human cornea. Vision Research, 46(6-7), 993-1001.
Dubbelman M, Sicam VA, Van der Heijde GL. The Shape of the Anterior and Posterior Surface of the Aging Human Cornea. Vision Res. 2006;46(6-7):993-1001. PubMed PMID: 16266736.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The shape of the anterior and posterior surface of the aging human cornea. AU - Dubbelman,M, AU - Sicam,V A D P, AU - Van der Heijde,G L, Y1 - 2005/11/02/ PY - 2005/06/29/received PY - 2005/09/16/revised PY - 2005/09/21/accepted PY - 2005/11/4/pubmed PY - 2006/12/9/medline PY - 2005/11/4/entrez SP - 993 EP - 1001 JF - Vision research JO - Vision Res. VL - 46 IS - 6-7 N2 - PURPOSE: To determine the shape and astigmatism of the posterior corneal surface in a healthy population with age, using Scheimpflug photography corrected for distortion due to the geometry of the Scheimpflug imaging system and the refraction of the anterior corneal surface. METHODS: Scheimpflug imaging was used to measure in six meridians the cornea of the right eye of 114 subjects, ranging in age from 18 to 65 years. RESULTS: The average radius of the anterior corneal surface was 7.79+/-0.27 (SD) mm and the average radius of the posterior corneal surface was 6.53+/-0.25 (SD) mm. Both surfaces were found to be flatter horizontally than vertically. The cylindrical component of the posterior surface of 0.33 mm is twice that of the anterior surface (0.16 mm). The asphericity of both the anterior and the posterior surface was independent of the radius of curvature at the vertex, refractive error and gender. In contrast with that of the anterior corneal surface, the asphericity of the posterior corneal surface varied significantly between meridians. With age, the asphericity of both the anterior and the posterior corneal surface changes significantly, which results in a slight peripheral thinning of the cornea. CONCLUSION: On average, the astigmatism of the posterior corneal surface (-0.305 D) compensates the astigmatism of the anterior corneal surface (0.99 D) with 31%. The results show that the effective refractive index is 1.329, which is lower than values commonly used. There is no correlation between the asphericity of the anterior and the posterior corneal surface. As a result, the shape of the anterior corneal surface provides no definitive basis for knowing the asphericity of the posterior surface. SN - 0042-6989 UR - https://www.unboundmedicine.com/medline/citation/16266736/The_shape_of_the_anterior_and_posterior_surface_of_the_aging_human_cornea_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0042-6989(05)00490-6 DB - PRIME DP - Unbound Medicine ER -