1. Long-Term Longitudinal Change in Keratometry After Pediatric Cataract Surgery Rupal H. Trivedi, MD MSCR M. Edward Wilson, MD Osman Melih, MD Dipankar Bandyopadhyay, Ph.D Storm Eye Institute Medical University of South Carolina The authors have no financial interest Rupal H. Trivedi, MD MSCR M. Edward Wilson, MD Osman Melih, MD Dipankar Bandyopadhyay, Ph.D Storm Eye Institute Medical University of South Carolina The authors have no financial interest

2. Purpose To report longitudinal change in keratometry after pediatric cataract surgery

3. Methods Hand-held keratometer; Used according to the operator’s manual; As soon as possible after induction of anesthesia; Before A-scan helps avoid irregular mires; Average of repeated measurements; K value was calculated as average of K1 and K2

4. Methods Inclusion criteria: Eyes underwent pediatric cataract surgery Exclusion criteria: Traumatic cataract, Unavailability of preoperative and at least one postoperative keratometry data Statistical analysis: We fitted Generalized Estimating Equation Models (GEE) in SAS using PROC GENMOD, which takes care of the clustering as well as repeated measures for eyes within subjects. All parameters are tested for their significance at 5% level.

5. Results N = 251 patients Number of postoperative observations (preop and all postop) = 781 Age at surgery: 2.8 ±3.3 years Gender: M, 128 (51%); F, 123 (49%) Race: White, 178 (70.9%); Af-Am, 57 (22.7%); Others, 16 (6.4%) Primary IOL implantation: Y, 185 (73.7%); N, 66 (26.3%) Follow-up duration: 3.9 ±3.1 years Age at last follow-up: 6.7 ±4.5 years

6. Keratometry P < 0.001

7. Difference of preoperative keratometry and postoperative keratometry was 1.33 D (95% CI, 1.06 - 1.60, P<0.001) Unilateral cataract: 1.53 ±0.21 D Bilateral cataract: 1.16 ±0.18 D, P >0.05 In Unilateral cataract (when fellow eye data were available both preop and postop): cataract eye, 1.42 ±2.04 D fellow eye, 1.29 ±1.72 D, P>0.05 Results

8. Postoperative keratometry = 17.19 + 0.58x 1 + 1.43 x 2 -0.04 x 3 + 0.24 x 4 -0.15x 5 x 1 = preoperative keratometry in D (P<0.001), x 2 = IOL implantation, where 0 is no and 1 is yes (P<0.001), x 3 = Follow-up duration in years (P=0.04), x 4 = Laterality of cataract, where 0 is no and 1 is yes (P=0.14) x 5 = Axial length growth in mm (postoperative axial length minus preoperative axial length) (P=0.003) Scaled Chi-square tests suggest model fit is adequate. (P-value = 0.43). This suggests that with increasing follow-up and with more axial length growth, keratometry values flattened.

9. Bilateral Postoperative keratometry = 19.74 + 0.02x 1 + 0.52 x 2 + 1.80x 3 - 0.06 x 4 -0.08x 5 x 1 = Eye, where 1 is right eye, 2 is left eye (P=0.58), x 2 = Preoperative keratometry in D (P<0.001) x 3 = IOL implantation, where 0 is no and 1 is yes (P<0.001), x 4 = Follow-up duration in years (P=0.04), x 5 = Axial length growth in mm (postoperative axial length minus preoperative axial length) (P=0.15) Scaled Chi-square tests suggest model fit is adequate. (P-value = 0.41)

10. Unilateral Postoperative keratometry = 18.97 + 0.56x 1 + 0.22 x 2 + 0.002x 3 - 0.32 x 4 x 1 = Preoperative keratometry in D (P<0.001) x 2 = cataract, where 0 is no and 1 is yes (P=0.06), x 3 = Follow-up duration in years (P=0.95), x 4 = Axial length growth in mm (postoperative axial length minus preoperative axial length) (P=0.001) Scaled Chi-square tests suggest model fit is adequate (P-value = 0.41)

11. Postoperative K value can be predicted by knowing preop K, presence or absence of IOL, follow-up duration, laterality of cataract and axial length growth Keratometry values change significantly after cataract surgery, however the change appears to be influenced by eye growth as the child ages. Although in unilateral cataract cases, the eyes operated for cataract showed a different growth as compared to fellow eyes without cataract, this difference was not statistically significant. Conclusion

12. Eyes with higher preoperative keratometry values tend to have higher postoperative keratometry values; In the model we constructed, duration of follow-up and axial length growth significantly add to the prediction of the postoperative keratometry value. The longer the duration of follow-up, the less the keratometry value is. The higher the axial length growth, the less the keratometry value is. Eyes with unilateral cataract flattened more as compared to eyes with bilateral cataract, however, the difference was not statistically significant. In bilateral cataract cases, both eyes showed similar growth.