[Are diurnal and nocturnal intraocular pressure measurements over 48 h justified?].
OBJECTIVE
Diurnal intraocular pressure (IOP) measurements are recommended in cases of visual field deterioration in glaucoma patients. In this study the rationale of 24 h versus 48 h IOP measurements was investigated.


METHODS
Mean IOP and maximum IOP values were obtained in 80 patients over a period of 48 h. The IOP measurements (Goldmann tonometry) of day 1 and 2 (taken every 4 h) were compared. To reduce interindividual and intraindividual differences of measurements the statistical calculation took a tolerance level of ± 2 mmHg and ± 1 mmHg into account.


RESULTS
Maximum IOP measurements were found to differ between 37.5 % and 65.0% respectively for right eyes and 28.8 % and 47.5% respectively for left eyes depending on the measurement tolerance (±2 mmHg or ±1 mmHg) between day 1 and day 2. Mean IOP values were found to differ by 25 % and 51.3 % respectively for right eyes and 26.3 % and 46.3% respectively for left eyes (± 2 or ± 1 mmHg in) between day 1 and day 2. A time-related clustering of extreme deviations could not be found but the maximum values from all patients were found to be roughly equally distributed over daytime and nighttime hours.


CONCLUSIONS
Both maximum IOP and mean IOP measurements were found to differ by at least ± 2 or ± 1 mmHg between day 1 and 2 at a significant percentage and the maximum values did not peak at a predictable time point during the 48 h. Therefore, 48 h IOP measurements appear to be more reliable than 24 h measurements.
Klinik und Poliklinik für Augenheilkunde, Justus-Liebig-Universität Gießen, Universitätsklinikum Gießen und Marburg GmbH, Standort Gießen, Friedrichstr. 18, 35392, Gießen, Deutschland.
N
N
Fischer
F
F
Weinand
M U
MU
Kügler
S
S
Scheel
B
B
Lorenz
D000368:Aged; D002940:Circadian Rhythm; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014065:Tonometry, Ocular / Q000379:methods*