A prospective study found that the Haigis, Kane, and Barrett Universal II formulas yielded comparable and superior outcomes for intraocular lens power calculation in patients with primary angle closure disease (PACD) undergoing cataract surgery. 

The study, published in the Journal of Glaucoma, compared the accuracy of 6 intraocular lens (IOL) power calculation formulas in 105 eyes with primary angle closure disease and 35 eyes with age-related cataracts from January 2020 to August 2021 at Xiamen Eye Center.

The Haigis formula demonstrated the highest percentage of eyes with prediction error (PE) within ±0.50 diopters (D) at 83.81%, followed closely by Kane (79.05%) and Barrett Universal II (BU II) (78.10%). These three formulas significantly outperformed Hoffer Q (53.30%), Holladay I (66.60%), and SRK/T (67.62%) in predicting postoperative refractive outcomes for PACD patients.

Key findings included:

1. Median absolute prediction error (MedAE) for PACD eyes: BU II: 0.21 D, Haigis: 0.27 D, Kane: 0.26 D, Hoffer Q: 0.48 D, Holladay I: 0.37 D, SRK/T: 0.34 D
2. PACD eyes with axial length (AL) >22 mm (n=62) achieved lower MedAE values compared to those with AL ≤22 mm (n=43), although the difference was not statistically significant.
3. IOL power prediction was less accurate in PACD eyes compared with normal cataract eyes when using the BU II formula (78.1% vs 85.71% of eyes within ±0.50 D, P<0.05).
4. Correlation analysis revealed that PE calculated by BU II was significantly positively correlated with AL (r=0.442, P=0.000) and negatively correlated with relative lens position (RLP) (r=-0.410, P=0.000).
5. PACD eyes had unique anatomical features compared to normal cataract eyes:
   • AL: 22.19 ± 0.77 mm vs. 23.62 ± 0.83 mm (P<0.05)
   • Aqueous depth: 1.78 ± 0.22 mm vs. 2.69 ± 0.3 mm (P<0.05)
   • Lens thickness: 4.93 ± 0.28 mm vs. 4.34 ± 0.4 mm (P<0.05)
   • RLP: 0.215 ± 0.01 vs. 0.227 ± 0.01 (P<0.05)

Subgroup analysis of PACD patients with short AL (≤22 mm, n=43) vs long AL (>22 mm, n=62) revealed:

• Short AL group had significantly more females (88.4% vs 71.0%, P<0.05)
• Short AL group had thinner lenses (4.67 ± 0.21 mm vs 4.97 ± 0.28 mm, P<0.05)
• Short AL group had more posteriorly positioned lenses (RLP: 0.221 ± 0.01 vs 0.211 ± 0.01, P<0.05)

The researchers noted that 5 PACD patients had large refractive PEs (>0.9 D), all with abnormal lens positions. AL ranged from 19.87 mm to 23.71 mm, and aqueous depth ranged from 1.33 mm to 2.00 mm in these cases.

The study used a one-piece aspherical acrylic monofocal IOL (PCB00, Johnson & Johnson Vision) for all patients. Surgeries were performed by a single surgeon using a standardized technique.

This study provided comprehensive data on IOL power calculation formulas in PACD patients, including detailed biometric measurements, subgroup analyses, and comparisons with normal cataract patients.

Conflict of interest disclosures were not made available at time of publishing.