central corneal thickness and intraocular pressure in ocular hypertension
TRANSCRIPT
for glaucoma, have no evidence of this neuropathy [5]. Ophthalmologistshave suggested that some optic nervesare less susceptible to an elevated IOPthan others, but we have often forgot-ten the impact of central corneal thick-ness (CCT) on applanation tonometry.
Recently Wolfs et al. have pointedout that there is an increase in IOP of0.19 mmHg with each 10 µm in-crease in CCT in both eyes and bothsexes [6]. So IOP is positively relatedto CCT. Recent studies have demon-strated that increased CCT can occurin patients with ocular hypertension,which can lead to falsely elevatedIOP readings [1]. Several studieshave attempted to determine whetherpatients with ocular hypertensionshould or should not be treated, butthe CCT was not considered in anyof them [2, 4]. So the final results ofthese studies could be imprecise be-cause of the study design, since it ispossible that false ocular hyperten-sion patients were included in thesestudies. We would like to emphasizethe necessity to include the measure-ment of CCT in hypertension patientsin order to understand and classifythe different types of this disease.
References
1. Bechmann M, Thiel MJ, Roesen B,Ullrich S, Ulbig MW, Ludwig K
(2000) Central corneal thickness deter-mined with optical coherence tomo-graphy in various types of glaucoma.Br J Ophthalmol 84:1233–1237
2. Gordon MO, Kass MA (1999) The Ocular Hypertension Treatment Study:design and baseline description of theparticipants. Arch Ophthalmol117:573–583
3. Heijl A, Bengtsson B (2000) Long-term effects of timolol therapy in ocu-lar hypertension: a double-masked,randomised trial. Graefes Arch ClinExp Ophthalmol 238:877–883
4. Miglior S, Pfeiffer N, Cunha-Vaz J,Zeyen T (1999) European glaucomaprevention study. Objectives and methods. Invest Ophthalmol Vis Sci[Suppl] 40:566
5. Rossetti L, Marchetti I, Orzalesi N,Scorpiglione N, Tocri V, Ljberati A(1993) Randomized clinical trials onmedical treatment of glaucoma. Arethey appropriate to guide clinical prac-tice? Arch Ophthalmol 111:96–103
6. Wolfs RC, Klaver CC, Vingerling JR,et al (1997) Distribution of central cor-neal thickness and its association withintraocular pressure: the Rotterdamstudy. Am J Ophthalmol 123:767–772
C. Gutierrez (✉ ) · F. Munoz G. RebolledaDepartment of Ophthalmology, Ramon y Cajal Hospital, Madrid, Spaine-mail: [email protected]
J.R.V. CasaponsaInstituto Oftalmológico de Albacete, Albacete, Spain
Correspondence address:C. Gutierrez, c/Mercurio 63, 2B, 28023 Madrid, Spain
Graefe’s Arch Clin Exp Ophthalmol(2001) 239:463
DOI 10.1007/s004170100290
L E T T E R T O T H E E D I T O R
Consuelo GutierrezJose R. V. CasaponsaFrancisco MunozGema Rebolleda
Central corneal thicknessand intraocular pressure in ocular hypertensionReceived: 25 January 2001Published online: 22 June 2001© Springer-Verlag 2001
Sir
We read with great interest the articleby A. Heijl and B. Bengtsson entitled“Long term effects of timolol therapyin ocular hypertension: a doublemasked, randomized trial” [3].
As in other studies they failed toprove a beneficial effect of topical ti-molol treatment in patients with ele-vated intraocular pressure (IOP), nor-mal visual fields and some additionalrisk factors. An elevated IOP is themain risk factor for the developmentof glaucoma. Therefore, a reduction inIOP, in theory, must reduce the inci-dence of glaucoma in patients with oc-ular hypertension, but several studieshave demonstrated that a majority ofpatients, in spite of having ocular hy-pertension and even other risk factors