IOP in Chinese eyes.

Abstract

Except for epicanthus, there are no known peculiarities to Chinese eyes, hence the wonder of the article “Accuracy of Clinical Estimates of Intraocular Pressure in Chinese Eyes” (Ophthalmology 2000;107:1816–21). As for accuracy, in 1960 I had pointed to the metaphysical basis of Goldmann’s tonometer,1Markiewitz H.H The so-called Imbert-Fick law.Arch Ophthalmol. 1960; 64 ([letter]): 159Crossref PubMed Scopus (10) Google Scholar and then shown in 400 eyes that its readings are influenced by corneal curvature.2Mark H.H Corneal curvature in applanation tonometry.Am J Ophthalmol. 1973; 76: 223-224PubMed Scopus (161) Google Scholar In a recent study of 513 eyes, we found that a change in axial length of 1 mm changed the tonomerter’s reading by 0.29 units.3Mark HH, Robbins KP, Mark TL. Axial length in applanation tonometry. In Press. J Cataract Refract Surg.Google ScholarIt is well known that myopia is often associated with large elongated globes, which leads to underestimation of tonometric readings, as Sir Stewart Duke-Elder4Duke-Elder, S, editor-in-chief. System of Ophthalmology, The Physiology of the Eye and of Vision. Vol. 4. St. Louis: CV Mosby, 1968;272.Google Scholar put it: “we would expect larger eyes to have lower values of K [coefficient of ocular rigidity] than smaller eyes, just as a container with a capacity of 100 ml, would be easier to distend when 1 ml of fluid was injected into it than a similar container with a capacity of 10 ml.” The researchers at Singapore’s National Eye Center, whence the article originated, have also recently found that childhood myopia in Singapore is four times higher than in the United States, as is also adult myopia in East Asia in general.Racial attitudes in Singapore or the Malayan peninsula aside, the tonometric underestimation the six authors found in their 23 Chinese may well be due to physical rather than ethnic causes. It would therefore be enlightening to see some data of these eyes, such as average axial length, central corneal thickness, and refractive error. Except for epicanthus, there are no known peculiarities to Chinese eyes, hence the wonder of the article “Accuracy of Clinical Estimates of Intraocular Pressure in Chinese Eyes” (Ophthalmology 2000;107:1816–21). As for accuracy, in 1960 I had pointed to the metaphysical basis of Goldmann’s tonometer,1Markiewitz H.H The so-called Imbert-Fick law.Arch Ophthalmol. 1960; 64 ([letter]): 159Crossref PubMed Scopus (10) Google Scholar and then shown in 400 eyes that its readings are influenced by corneal curvature.2Mark H.H Corneal curvature in applanation tonometry.Am J Ophthalmol. 1973; 76: 223-224PubMed Scopus (161) Google Scholar In a recent study of 513 eyes, we found that a change in axial length of 1 mm changed the tonomerter’s reading by 0.29 units.3Mark HH, Robbins KP, Mark TL. Axial length in applanation tonometry. In Press. J Cataract Refract Surg.Google Scholar It is well known that myopia is often associated with large elongated globes, which leads to underestimation of tonometric readings, as Sir Stewart Duke-Elder4Duke-Elder, S, editor-in-chief. System of Ophthalmology, The Physiology of the Eye and of Vision. Vol. 4. St. Louis: CV Mosby, 1968;272.Google Scholar put it: “we would expect larger eyes to have lower values of K [coefficient of ocular rigidity] than smaller eyes, just as a container with a capacity of 100 ml, would be easier to distend when 1 ml of fluid was injected into it than a similar container with a capacity of 10 ml.” The researchers at Singapore’s National Eye Center, whence the article originated, have also recently found that childhood myopia in Singapore is four times higher than in the United States, as is also adult myopia in East Asia in general. Racial attitudes in Singapore or the Malayan peninsula aside, the tonometric underestimation the six authors found in their 23 Chinese may well be due to physical rather than ethnic causes. It would therefore be enlightening to see some data of these eyes, such as average axial length, central corneal thickness, and refractive error. Author replyOphthalmologyVol. 108Issue 8Preview Full-Text PDF