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Predictability of formulae for intraocular lens power calculation according to the age of implantation in paediatric cataract
  1. Byung Joo Lee1,
  2. Sang-Mok Lee2,
  3. Jeong Hun Kim1,3,
  4. Young Suk Yu3
  1. 1 Department of Biomedical Sciences, College of Medicine, Seoul National University, Seoul, South Korea
  2. 2 HanGil Eye Hospital, Catholic Kwandong University College of Medicine, Incheon, South Korea
  3. 3 Department of Ophthalmology, Seoul National University Hospital, Seoul, South Korea
  1. Correspondence to Dr Young Suk Yu, Department of Ophthalmology, Seoul National University Hospital, Seoul 110-744, South Korea; ysyu{at}


Aims To analyse the predictability of diverse intraocular lens (IOL) power calculation formulae in paediatric patients with congenital cataract.

Methods The medical records of patients who underwent cataract surgery and posterior chamber IOL implantation (in-the-bag) for congenital cataract before 17 years of age were reviewed retrospectively. Target refractions calculated by Sanders-Retzlaff-Kraff (SRK)/II, SRK/T and Hoffer-Q formulae were compared with the actual refraction. Patients were subgroup according to the age at IOL implantation (age group 0–24 months, 25–60 months, 61–120 months, 121–203 months), and we compared mean prediction error (PE) and mean absolute error (AE) for each formula. Corrected AE was obtained by linear regression analysis.

Results Totally 481 eyes were included in the final analysis. Both SRK/II and SRK/T yielded the lowest mean AE in the age group 0–24 months and SRK/II yielded the lowest mean AE in the age group 25–60 months. For every formula, the mean PE was positive during the first five years of age, which converged to zero according to age as IOL implantation increases. The tendency for immediate postoperative overcorrection in younger patients (<6 years) could be improved by corrected formulae based on the linear regression equation.

Conclusions Patients with congenital cataract who underwent IOL implantation within 5 years of age showed higher AE than the older ones did. Among the three formulae evaluated, SRK/II consistently provided the best predictive result in these patients. For patients aged >10 years, all three formulae showed favourable predictive abilities.

  • child health (paediatrics)
  • lens and zonules
  • treatment surgery

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  • Contributors BJL contributed to the acquisition, analysis and interpretation of data and drafting the article. S-ML contributed to the conception of ideas and design of study and critical revision of contents. JHK contributed to the conception of ideas and design of study and critical revision of contents. YSY contributed to the conception of ideas and design of study, critical revision of contents and provided approval of version to be published.

  • Funding This study was supported by the Seoul National University Hospital Research Grant (23-2016-0080).

  • Competing interests None declared.

  • Ethics approval The Institutional Review Board of Seoul National University Hospital has approved this study.

  • Provenance and peer review Not commissioned; internally peer reviewed.

  • Patient consent Detail has been removed from this case description to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

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