Refractive change and optical biometry dynamics after 25-gauge vitrectomy in pseudophakic eyes

Distribution and Characteristics of Ocular Biometric Parameters among a Chinese Population: A Hospital-Based Study

INTRODUCTION

This study aimed to describe the distribution and characteristics of ocular biometric parameters among a large Chinese population.

METHODS

This retrospective cross-sectional study included 146,748 subjects whose ocular biometric parameters were measured at the ophthalmology clinic of West China Hospital, Sichuan University, and recorded in the hospital database. Ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, were recorded. Only monocular data for each subject were analyzed to avoid bias.

RESULTS

Valid data from 85,770 subjects (43,552 females and 42,218 males) aged 3-114 years were included in this study. The mean axial length, mean anterior chamber depth, average corneal keratometry, and mean keratometric astigmatism were 24.61 mm, 3.30 mm, 43.76 D, and 1.19 D, respectively. The stratification of the ocular parameters by age and gender showed significant inter-gender and inter-age differences.

CONCLUSIONS

Analysis of a large population of subjects in western China aged 3-114 years showed that the distribution and characteristics of ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, differed by age and gender. This study is the first to describe ocular biometric parameters in subjects aged > 100 years.

Prospective comparison of accuracy of intraocular lens calculation formulas in phacovitrectomy: a pilot study in a real-world clinical practice

PURPOSE

To compare the accuracy of intraocular lens (IOL) power calculations among IOL formulas after phacovitrectomy.

METHODS

We prospectively enrolled 206 eyes of 206 patients who underwent 25-gauge phacovitrectomy, without gas tamponade, for macular pathology. Pre-operative optical biometry used the IOLMaster 700 to calculate the IOL power with the new formulas, i.e. the Barrett Universal II (BU II), Emmetropia Verifying Optical version 2.0, Hill-Radial Basis Function (RBF) version 3.0, Kane, and Ladas Super Formula, and conventional formulas, i.e. Haigis, Hoffer Q, Holladay 1, Holladay 2, and Sanders-Retzlaff-Kraff/T (SRK/T). A single-piece foldable IOL was implanted in all cases. Manifest refractions were measured before and 3 months after surgery.

RESULTS

The BU II formula showed the lowest standard deviation and mean and median absolute errors and had the highest percentage of eyes with a refractive prediction error within ± 0.25 D. The absolute error was significantly lower with the four new formulas, except the Hill-RBF, than with the Hoffer Q (all p =  ≤ 0.010) and Holladay 1 formulas (all p =  < 0.010). The absolute error with the BU II formula was also lower than that with the Holladay 2 (p = 0.012) and SRK/T (p = 0.024) formulas.

CONCLUSION

Overall, the new IOL formulas, except the Hill-RBF, were superior to some of the conventional formulas for calculating IOL power in phacovitrectomy.