Accuracy Of Target Refraction In Pediatric Patients Undergoing Yamane Intrascleral Haptic Fixation Intraocular Lens Implantation: A Retrospective Pilot Study

The implantation of intraocular lenses (IOLs) is a common procedure for visual rehabilitation in pediatric cataracts, aphakia, and ectopia lentis. In recent years, the Yamane Flanged intrascleral haptic fixation technique has emerged as a viable alternative, offering stable and secure fixation of IOLs in the absence of capsular support. This study aims to evaluate the accuracy of target refraction achieved with Yamane intrascleral haptic fixation IOL implantation in pediatric patients and to determine the magnitude and direction of prediction error associated with this surgical technique to guide the selection of target refraction in future cases, thereby optimizing visual outcomes in this population.

Despite its increasing popularity, there remains limited data regarding the prediction error of target refraction associated with the Yamane technique in pediatric patients. Published studies mostly report in adult population, This retrospective pilots study was conducted at a tertiary eye care center, where the Yamane technique was recently adopted for scleral fixated IOL implantation in pediatric patients from the year of 2023 and a minimum of 1month follow-up was required.  

The medical records of children age <15 years old which included lens subluxation and non-capsular supported aphakic correction who underwent flanged intrascleral IOL implantation during a year of 2023 were reviewed retrospectively. A-uniform procedure which included 2 mm scleral tunnel 2 mm apart from the limbus were created for intrascleral haptic fixation 180 degree apart. Pre- and postoperative best corrected visual acuity (BCVA) were compared using a Paired t-test, Spherical equivalent at 1 and 6 months post-operation and pre-operative refractive target to assess prediction error (PE) calculated by SRK-T formula were both compared and analyzed using Generalize Estimating Equation (GEE). 

The study included 10 eyes from 6 patients.The mean age of the patients was 8.8 ± 2.5 years and mean follow up time was 4.6 ± 2.5 months. The preoperative and postoperative best corrected visual acuity was 0.87± 0.15 and 0.52 ± 0.17 logMAR, respectively. All patients had an increase in the BCVA with a mean value of 0.35 ± 0.2 logMAR, which was statistically significant (P<0.001). The median target refraction was -0.75 (IQR -0.84, -0.63). The mean PE at 1 month and 6 months follow up were 1.14 ±1.90 and -0.18 ± 1.77 diopters, respectively. Compared with ideal zero error of PE, the mean different of PE at 1 and 6 months were 1.44 (95%CI 0.04, 2.84, p=0.04) and 0.08 (95% CI -1.54, 1.70, p=0.93) respectively. 

Careful consideration in selecting the target power of the IOL is crucial for pediatric patients undergoing Yamane intrascleral haptic fixation. While initial PE tends towards hyperopia, it gradually approaches the target refraction over six months post-operation. Further studies with larger sample sizes are warranted to refine IOL power selection in pediatric cases utilizing this technique.