1. Effects of IOP Lowering Agents on Myopic Regression after Refractive Surgery Lim, Taehyung M.D., Hong, So Jin M.D., Cho, Beom Jin M.D., Ph.D. Chung Kyu-Hyung M.D, Ph.D, Choi Kee-Yong M.D, Ph.D. HanGil Eye Hospital * All authors have no financial interest in the subject matter of this poster.

2. Background The higher IOP, the more anterior shifting of the cornea Factors affecting the forward shift of posterior corneal surface after laser in situ keratomileusis. Baek T, et al, 108(2):317-20, 2001, Ophthalmology Factors affecting the forward shift of posterior corneal surface after laser in situ keratomileusis. Baek T, et al, 108(2):317-20, 2001, Ophthalmology Differences between regressive eyes and non-regressive eyes after LASIK for myopia in the time course of corneal changes assessed with the Orbscan. Pan, et al, 218(2):96-101, 2004, Ophthalmologica Differences between regressive eyes and non-regressive eyes after LASIK for myopia in the time course of corneal changes assessed with the Orbscan. Pan, et al, 218(2):96-101, 2004, Ophthalmologica Regressive eye vs. Non-regressive eye differed in the corneal shifting movements after LASIK Regression-related factors before and after laser in situ keratomileusis. Qi H. et al, 220(4):272-6,2006 Ophthalmologica Regression-related factors before and after laser in situ keratomileusis. Qi H. et al, 220(4):272-6,2006 Ophthalmologica IOP lowering may prevent myopic regression. Evidences of correlation between IOP and refractive error after LASIK

3. Background Effects of antiglaucoma drugs on refractive outcomes in eyes with myopic regression after laser in situ keratomileusis. Kamiya K, et al, 145(2):233-238, Am J Ophthalmol, 2008 Effects of antiglaucoma drugs on refractive outcomes in eyes with myopic regression after laser in situ keratomileusis. Kamiya K, et al, 145(2):233-238, Am J Ophthalmol, 2008 27 eyes with myopic regression after LASIK Mean regression : 1.26±0.48D(-0.5 ~ -2.25D) 2.5 % Nipradilol bid for 3months Pretreatment3 Months Spherical-1.02±0.52D-0.44±0.39D* Astigmatism-0.55±0.30D-0.49±0.22D IOP11.4±2.4mmHg9.1±8.2mmHg* CCT505.2±39.3um505.6±38.7um 15% of patients did not respond to the treatment. Evidences of correlation between IOP and refractive error after LASIK

4. Background Pretreatment3 Months Mean refractive power of the total cornea (3mm) 38.4±2.0D37.7±2.0D Posterior corneal surface shifted posteriorly by 9.1±8.2um (mean) It is suggested that backward movement of the cornea may occur, possibly flattening the corneal curvature by lowering the IOP Effects of antiglaucoma drugs on refractive outcomes in eyes with myopic regression after laser in situ keratomileusis. Kamiya K, et al, 145(2):233-238, Am J Ophthalmol, 2008 Effects of antiglaucoma drugs on refractive outcomes in eyes with myopic regression after laser in situ keratomileusis. Kamiya K, et al, 145(2):233-238, Am J Ophthalmol, 2008 Evidences of correlation between IOP and refractive error after LASIK

5. Purpose To evaluate effects of IOP lowering agents on patients who have myopic regression after laser vision correction(LVC)

6. Methods 94 eyes in 47 patients (Male = 11, Female = 36) Mean age : 33.7 years (22~53) Patients who have myopic regression after LVC Occurrence of Myopic regression after LVC : postoperative 4y5m ± 3y11m (1month ~ 12 years) OpPRKLASIKLASEK Number96520

7. Methods At the time of diagnosis, treatment was started with topical 0.5% timolol + 5% dorsolamide combination (Cosopt ®, MSD, USA), twice daily for 3 months. Outcome parameters : UCVA, BCVA, IOP, CCT, MR, Topography and ACD f/u period : 1 week, 1 month, 3 months

8. Results Pre- treatment Post-treatment 1 month Post-treatment 3 months Spherical error (D)*-1.02±1.55-0.50±1.27-0.41±0.92 Astigmatism (D)-0.23±0.78-0.18±0.77-0.18±0.67 IOP(mmHg)*10.55±5.759.17±3.699.64±3.78 CCT(um)486.9±95.1 481.6±109.1 ACD(um)3.23±0.503.29±0.613.27±0.58 Keratometry(D) † Anterior Posterior 39.61±3.77 -6.43±0.64 38.36±3.94 -6.36±0.51 39.43±3.36 -6.41±0.55 * p < 0.05, paired T test for pre-treatment & Post-treatment 3 months † p < 0.05, paired T test for pre-treatment & Post-treatment 1 month

9. Results * Refractive improvement : manifest refraction error (spherical or cylindrical) improvement of more than 0.5D Refractive Improvement*UCVA improvement 73.3%87.5 % Pre-treatment Post-treatment 1 month Post-treatment 3 month UCVA(logMAR)*0.38±0.510.17±0.410.15±0.39 BCVA(logMAR)0.01±0.060.01±0.070.01±0.08 * p < 0.05, paired T test for pre-treatment & Post-treatment 3 months Refractive error and UCVA changes through 3 months treatment

10. Change of UCVA(LogMAR) UCVA (LogMAR) improved significantly through 3 months treatment.(p<0.05)

11. Conclusion UCVA improved in 87.5% of patients much more than that of refractive error improvement(73.3%). It is suggested that IOP lowering may induce the change of corneal curvature, according to 1-month result. IOP lowering agents may be helpful to reduce myopic regression.

12. Discussion Although 3-month result showed no statistically significant change in corneal curvature, it is still though to be important mechanism that IOP lowering may induce the change of corneal curvature. Long term follow-up should be needed. We stopped the medication at 3 months and are evaluating patients to confirm the effect and mechanism.