The importance of central corneal thickness measurements and decision making in general ophthalmology clinics: a masked observational study

BackgroundTo assess the impact of knowing central corneal thickness (CCT) on glaucoma management in a United Kingdom district general hospital.MethodsA masked observational non-interventional study included 304 eyes of 152 consecutive glaucoma cases attending general clinic. CCT was measured using a hand-held pachymeter. IOP, as measured by the Goldmann applanation tonometer (GAT), was adjusted for CCT using a normogram. Two identical study sheets were retrospectively constructed from each subject's case notes: one included the CCT and adjusted IOP information, the other excluded. Study sheets were randomly presented to a single masked observer to decide glaucoma management. The difference in management decision was noted.ResultsThe mean ± standard deviation CCT was 561.5 ± 35.7 μm, 538.9 ± 41.4 μm, 538.3 ± 40.3 μm for ocular hypertension (OHT), primary open angle glaucoma (POAG) and normal pressure glaucoma (NPG) subjects respectively. IOP adjustment was greater than ±2 mmHg in 33.9%(103/304) of eyes. CCT and adjusted IOP information led to different treatment option in 37%(55/152). Of the most important changes 20.4%(31/152) cases would have been commenced on additional IOP-lowering medication, 2.0%(3/152) would have been counselled for trabeculectomy surgery and 3.3%(5/152) of the cohort would have been observed rather than treated.ConclusionCCT and adjusted IOP measurement can influence glaucoma management in a clinical context. It helps attribute risk and hence aids patient management decisions.

[1]  J. Graff Zivin,et al.  Clinical significance of central corneal thickness in the management of glaucoma. , 2004, Archives of ophthalmology.

[2]  Shan C. Lin,et al.  Clinical comparison of contour and applanation tonometry and their relationship to pachymetry. , 2005, Archives of ophthalmology.

[3]  M. Whitacre,et al.  Sources of error with use of Goldmann-type tonometers. , 1993, Survey of ophthalmology.

[4]  M. Doughty,et al.  Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach. , 2000, Survey of ophthalmology.

[5]  Chris A. Johnson,et al.  The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. , 2002 .

[6]  R. Stein,et al.  The effect of corneal thickness on applanation tonometry. , 1993, American journal of ophthalmology.

[7]  M. C. Leske,et al.  The epidemiology of open-angle glaucoma: a review. , 1983, American journal of epidemiology.

[8]  M. C. Leske,et al.  Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. , 2003, Archives of ophthalmology.

[9]  D. Henson,et al.  Relationship between corneal thickness and measured intraocular pressure in a general ophthalmology clinic. , 1999, Ophthalmology.

[10]  M. C. Leske,et al.  Reduction of intraocular pressure and glaucoma progression: results from the Early Manifest Glaucoma Trial. , 2002, Archives of ophthalmology.

[11]  N. Ehlers,et al.  APPLANATION TONOMETRY AND CENTRAL CORNEAL THICKNESS , 1975, Acta ophthalmologica.

[12]  Chris A. Johnson,et al.  The Ocular Hypertension Treatment Study: baseline factors that predict the onset of primary open-angle glaucoma. , 2002, Archives of ophthalmology.

[13]  R. Stodtmeister,et al.  Applanation tonometry and correction according to corneal thickness. , 1998, Acta ophthalmologica Scandinavica.

[14]  Anders Heijl,et al.  Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. , 2003, Archives of ophthalmology.

[15]  B. Edmunds,et al.  Central corneal thickness: will one measurement suffice? , 2005, Ophthalmology.

[16]  E. E. Hartmann,et al.  The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. , 2002, Archives of ophthalmology.

[17]  D. Broadway,et al.  Evaluation of Tonometric Correction Factors , 2005, Journal of glaucoma.

[18]  Pre-publication history , 2001 .