Accuracy of Intraocular Lens Power Calculation Formula In Angle Closure Glaucoma

Taehoon Oh

Purpose: To compare the accuracy of intraocular lens (IOL) power calculation formulas in eyes with primary angle closure glaucoma (PACG).

Methods: This retrospective study compared the refractive outcomes of 63 eyes with primary ACG with the results of 93 eyes with normal open angles undergoing uneventful cataract surgery. Anterior segment biometry including anterior chamber depth(ACD), axial length(AL), anterior chamber depth to axial length ratio(ACD/AL) were compared by the IOLMaster(version 5, Carl-Zeiss, Germany). The third generation formulas (SRK-T, Hoffer Q) and fourth generation formula(Haigis) were used to predict IOL powers in both groups. Predictive accuracy of the formulas was analyzed by comparison of the mean error (ME) and the mean absolute error (MAE).

Results: In ACG patients, anterior chamber depth, axial length and anterior chamber depth to axial length ratio were smaller than normal controls (all p<0.05). The MAEs from ACG group were larger than that from control group. Comparing each formula, the mean absolute error from the Haigis formula was largest and that from the HofferQ formula was smallest.

Conclusions : IOL power prediction would be inaccurate in ACG patients. The Haigis formula induced less accurate results in ACG patients, and it is more appropriate to use the Hoffer Q formula predict IOL powers in eyes with PACG.