Comparison of Refractive Prediction Error by Axial Length in Flanged Intrascleral Intraocular Lens Fixation

Abstract

Purpose

To evaluate the refractive prediction error in flanged intrascleral intraocular lens (IOL) fixation using the SRK/T formula and compare the axial length using a single IOL.

Methods

Seventy-six eyes from 70 patients (45 males and 25 females) were included in this study. The mean age at the time of surgery was 73.4 ±12.3 years. The patients underwent flanged IOL fixation using a PN6A (Kowa). All surgeries were performed by two surgeons (Y. K. and T. O.) between Jan 2020 and Dec 2022 at Jikei University Daisan Hospital. IOL power was calculated using the SRK/T formula with IOL Master 700 (Carl Zeiss) as the bag power. The recommended value of 119.0 was used for the A-constant. The actual refractive spherical equivalent was calculated and compared with preoperative predictions. Refractive prediction errors were defined as the deviation of the actual postoperative spherical equivalent refraction in diopters from the predicted preoperative spherical equivalent refraction. The patients were divided into three groups according to axial length: <22.0 mm (short eyes), 22.0–24.5 mm (medium eyes), and >24.5 mm (long eyes), and the refractive prediction errors and mean absolute errors were compared.

Results

The mean refractive prediction error was −0.20 ± 0.52D. The mean absolute error was 0.44 ± 0.33D. The mean refractive prediction errors were not significantly different between the 22.0–24.5 mm (medium eyes) and >24.5 mm (long eyes) groups. (P=0.06) The mean absolute errors were not significantly different between the two groups (P=0.10).

Conclusion

The SRK/T formula worked well regardless of whether the eyes were medium or long according to the axial length in the flanged intrascleral IOL fixation.

Keywords:

• flanged intrascleral IOL fixation
• refractive prediction error
• SRK/T formula
• axial length

Disclosure

Tadashi Nakano: grants – Crewt Medical Systems, Kyowa Medical, Kuribara Medical Instruments, Tomey, MSD, Pfizer, Alcon Japan, NIDEK, AMO Japan, Bayer, IOL Medical, All Nippon Airway, Japan Airlines; personal fees – Nitto Medic, Nikon; grants and personal fees – Kowa, Otsuka Pharmaceutical, Senju Pharmaceutical, Santen Pharmaceutical, Carl Zeiss, outside the submitted work. The other authors declare no conflicts of interest.