Accuracy of Intraocular Lens Power Calculation Formulas in Primary Angle Closure Glaucoma

Abstract

PurposeTo compare the accuracy of intraocular lens (IOL) power calculation formulas in eyes with primary angle closure glaucoma (ACG).MethodsThis 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, axial length, and anterior chamber depth to axial length ratio were compared by the IOL Master. Third generation formulas (Hoffer Q and SRK/T) and a fourth generation formula (Haigis) were used to predict IOL powers in both groups. The predictive accuracy of the formulas was analyzed by comparison of the mean error and the mean absolute error (MAE).ResultsIn ACG patients, anterior chamber depth and the anterior chamber depth to axial length ratio were smaller than normal controls (all p < 0.05). The MAEs from the ACG group were larger than that from the control group in the Haigis formula. The mean absolute error from the Haigis formula was the largest and the mean absolute error from the Hoffer Q formula was the smallest.ConclusionsIOL power prediction may be inaccurate in ACG patients. The Haigis formula produced more inaccurate results in ACG patients, and it is more appropriate to use the Hoffer Q formula to predict IOL powers in eyes with primary ACG.

Factors affecting refractive outcome after cataract surgery in primary angle‐closure glaucoma

“…In a comparison the formulas of IOLMaster, Hoffer Q produced the least prediction error. This finding is consistent with a previous study using the IOLMaster formulas, which showed the Hoffer Q formula to induce better results than the SRK/T formula in angle‐closure glaucoma eyes . The Haigis formula produced the most hyperopic results in the present study.…”

“…Its inaccuracy might be caused by ACD biometric data. An increase of 1 mm ACD will cause a change in the postoperative refraction in the Haigis formula of 0.5 to 0.6 diopter . Increase in ACD was much higher in the patients with narrow angle so that ACD constant from based on normal eyes can cause a change in postoperative refraction.…”

Clear lens extraction for the management of primary angle closure glaucoma: surgical technique and refractive outcomes in the EAGLE cohort

“…The refractive accuracy is, however, less than that reported in an analysis of 17 056 eyes undergoing cataract surgery in Sweden, where 71% were within ±0.5D and 93% within ±1.0D 13. The EAGLE results compare favourably with the previous studies of refractive outcomes in patients with PACG where 49%–68% eyes (depending on the IOL power formula used) were reported to be within ±0.5D target in a study of 63 eyes14 and 77% eyes within 1.0D target refraction in a study of 49 eyes with PACG 15…”

Comparison of a new optical biometry with an optical low-coherence reflectometry for ocular biometry

“…The biometric variables that are used for intraocular lens (IOL) calculation depend on the chosen IOL formula. Current thirdgeneration and fourth-generation IOL power calculation formulas require the basic variables of axial length (AL), anterior chamber depth (ACD), keratometry (K), and corneal diameter (CD) values [1][2][3]. The IOL power calculation formulas achieve precise results in eyes with ALs between 22.0 and 25.0 mm.…”