Preoperative CDVA in KLEx Platforms Performance Evaluation [Letter]

Dear editor

We read with great interest the recent review article published on July 9, 2025, titled “Comparing the Existing Myopic Keratorefractive Lenticule Extraction (KLEx) Platforms: A Narrative Review” by Miller et al.¹ The authors provide a valuable synthesis of early and longer-term visual outcomes across the various KLEx platforms (SmartSight, CLEAR, SILK, SMILE, and SMILE Pro). However, we would like to highlight critical methodological oversight: the omission of explicit preoperative CDVA mentioning when comparing postoperative UDVA and assessing efficacy.

This could concern a reader since reporting the postoperative UDVA in the context of the preoperative CDVA is important to avoid apparent differences in refractive efficacy between studies.² Without this baseline, claims regarding visual gains or losses lack proper context and might be misleading.

While the information presented in the tables created by the authors is helpful, the absence of explicit preoperative CDVA data in each platform’s studies diminishes the strength of these efficacy-focused comparisons. For instance, if a certain platform’s cohort started with poor preoperative CDVA, a lower postoperative UDVA may not reflect the noteworthy improvement; conversely, if preoperative CDVA included mostly 20/20 and higher levels, then outcomes might not represent the stronger gains.

Moreover, omitting the preop CDVA might have led to a misassumption in the article that the discrepancy in the difference in visual outcomes reported in two studies^3,4 using CLEAR at 6 months and 1 year, 55% versus 100%, respectively, may be due to the differing mean ages reported in these studies.¹ This does not fully explain the reason for such difference, which is the preoperative 20/20 CDVA values, that were 58% in the paper by Leccisotti et al³ versus 98% in the article presented by Bteich et al.⁴ Also, this matter may not allow the reader to make clear conclusions when comparing with the other platforms’ performance.

We respectfully propose that the authors and the future comparative reviewers should aim to include summary statistics of preoperative CDVA for each platform or study cohort in the comparative tables, enabling readers to contextualize postoperative UDVA findings. Clearer baseline-outcome integration would greatly benefit readers, clinicians, and researchers evaluating KLEx technologies.