[A new predictive formula for anterior chamber depth for pseudophakia].
OBJECTIVE
To develop a new predictive formula of the anterior chamber depth(ACD) of the pseudophakic eyes for more accurate intraocular lens(IOL) power calculation with the Ray Tracing method.


METHODS
We studied a series of 149 phacoemulsificated eyes with capsulorhexis and in-the-bag fixation of IOL. ACD was measured with a Jaeger type depth measuring unit which was attached to a slit-lamp biomicroscope. We developed the formula with 3 variables: preoperative anterior corneal curvature with keratometer, and ACD and crystalline lens thickness with preoperative ultrasonography. We named the derived formula "formula H". We compared formula H with Olsen's predictive formula for the ACD(Olsen 92, Olsen 95).


RESULTS
Mean absolute error between the predicted and postoperatively measured ACD was 0.174 +/- 0.133, 0.280 +/- 0.235, 0.229 +/- 0.200 mm in formula H, Olsen 92, and Olsen 95, respectively. Formula H was significantly more accurate than both Olsen formulas(p < 0.001, p < 0.05, respectively).


CONCLUSIONS
The accuracy of IOL power calculation can be improved with the new formula using the Ray Tracing method, using the new ACD predictve formula.
Horiuchi
I
I
Horiuchi Eye Clinic, 2-71 Hokubu Yamashiro-onsen Kaga 922-0243, Japan.
Akagi
Y
Y
D000368:Aged; D000867:Anterior Chamber / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D008962:Models, Theoretical; D019591:Pseudophakia / Q000534:rehabilitation*