[Nomogram for ocular hypertension progression risk based on the ocular hypertension treatment study].
BACKGROUND
A practical nomogram has been designed in order to present the results obtained from the Ocular Hypertension Study (Gordon et al. Arch Ophthalmol 2002; 120: 714-720), where the relation between intraocular pressure (IOP) and corneal thickness becomes apparent, involving the risk of evolution from ocular hypertension into glaucoma within a 6 year period.


METHODS
We used a multiple logarithmic regression for the nine parameters shown in figure 1 of the above mentioned paper.


RESULTS
A correlation coefficient of 0.91 (p<0.001) permits to establish the following equation: Probability of evolution (%) = 13539.5 x (1.1385IOP) x (0.9818(CORNEAL THICKNESS)). This implies that a variation of 10 microns on corneal thickness leads to an IOP's modification of 1.5 mmHg in the same sense. From these data, we designed the nomogram included in this paper.


CONCLUSIONS
IOP and pachymetry together allow an estimation of the risk of evolution from ocular hypertension into glaucoma in a graphical practical way. From this indirect estimation, the influence of corneal thickness on IOP's measure seems to be much higher than previously estimated.
Díaz Alemán
V T
VT
Servicio de Oftalmología, Hospital Universitario de Canarias, Universidad de La Laguna, Islas Canarias, España. vtdac@hotmail.com
Fernández-Baca Vaca
G
G
Lozano López
V
V
García Somalo
M
M
Perera Sanz
D
D
González de la Rosa
M
M
D018450:Disease Progression; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D016015:Logistic Models; D049451:Nomograms; D009798:Ocular Hypertension / Q000175:diagnosis*; D012306:Risk; D014065:Tonometry, Ocular