Effects of complete suture removal on corneal topography, ocular biometry, and IOL power after keratoplasty: a comparative study of PK and DALK

BACKGROUND: Complete suture removal after keratoplasty may substantially alter corneal shape and ocular biometric measurements, thereby affecting intraocular lens (IOL) power calculations. However, comparative data on these changes after penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK), as well as factors predicting the magnitude of IOL power change, remain limited. This study aimed to evaluate topographic and biometric changes after complete suture removal in eyes undergoing PK or DALK and to identify predictors of calculated IOL power change. METHODS: This retrospective comparative study included 90 eyes of 90 patients who underwent PK (n = 44) or DALK (n = 46) at a tertiary referral ophthalmology center. Corneal topography and ocular biometry were assessed before and one month after complete suture removal. Anterior and posterior corneal curvature, corneal astigmatism, axial length, anterior chamber depth, and calculated IOL power were analyzed. Within-group and between-group comparisons were performed. Univariable and multivariable linear regression analyses were used to determine factors associated with change in calculated IOL power. RESULTS: Complete suture removal caused significant anterior corneal steepening and increased anterior chamber depth in both groups. Calculated IOL power decreased significantly after suture removal in both PK and DALK eyes, with a greater mean reduction in the PK group than in the DALK group (- 4.67 ± 5.42 D vs. -2.49 ± 4.65 D, respectively; p = 0.019). Posterior corneal astigmatism decreased significantly after PK but remained stable after DALK. Axial length did not change significantly in either group. In multivariable analysis, pre-removal anterior mean keratometry and host-donor diameter disparity were independently associated with change in calculated IOL power. CONCLUSIONS: Complete suture removal after keratoplasty induces clinically meaningful changes in corneal topography and ocular biometry, with a substantial impact on IOL power calculations. These changes are more pronounced after PK than after DALK. Repeat biometric assessment after complete suture removal should be considered before cataract or refractive surgery planning, particularly in eyes with steeper corneas or greater host-donor diameter disparity.