Effects of Pterygium Surgery on Holladay Eqiuvalent Keratometry Readings

Abstract

Aim: To investigate and compare the effects of pterygium surgery on the mean anterior surface Simulated Keratometry (SimK) and Holladay Equivalent Keratometry Readings-65 (EKR65) detail report. Methods: Patients who underwent pterygium surgery between August 2022 and January 2023 were examined. All surgeries were performed under local anesthesia with conjunctival autograft method. Pentacam topography was performed after detailed ophthalmological examination before and 3 months after surgery. The mean anterior SimK, EKR65 report results in all zones, mean anterior corneal radius (rfront) and mean posterior corneal radius (rback) parameters were investigated preoperatively and at 3 months. In addition, postoperative change amounts (Δ) of SimK and EKR65 data were calculated. Results: Twenty-four eyes of 24 patients were included in the study. The mean age of the patients was 51.50±9.48 (36-75) years. Mean anterior corneal surface SimK increased from 40.85±3.30 D, to 42.57±2.53 D at the postoperative 3rd month (p=0.003). The mean radius of curvature values on both anterior and posterior corneal surfaces decreased significantly (8.30±0.66 vs. 7.95±0.49, p=0.004, and 6.56±0.56 vs. 6.50±0.54, p=0.001, respectively). A general increase in EKR65 report values was observed in the postoperative period. Increases in EKR65 values at 4.5, 5, 6 and 7 mm were significant (p<0.05 for all). Both ΔEKR65 at 2mm and ΔEKR65 at 3mm were found to correlate with ΔSimK (r=0.371, p=0.044 and r=0.347, p= 0.046, respectively) Conclusion: Conventional keratometry calculations may be insufficient due to the irregularity of the cornea caused by pterygium surgery. The EKR65 report may be more prominent in these corneas.

Keywords

• Pterygium surgery
• Simulated keratometry
• EKR65
• corneal radius

Kaynakça

1. 1.Saglik A, Celik H. Comparison of Holladay equivalent keratometry readings and anterior corneal surface keratometry measurements in keratoconus. Int Ophthalmol. 2019; 39(7): 1501-9. https://doi.org/10.1007/s10792-018-0967-2
2. 2.Holladay JT, Hill WE, Steinmueller A. Corneal power measurements using scheimpflug imaging in eyes with prior corneal refractive surgery. J Refract Surg. 2009; 25(10): 862-8. https://doi.org/10.3928/1081597X-20090917-07 3.Aksoy M, Asena L, Güngör SG, et al. Comparison of refractive outcomes using Scheimpflug Holladay equivalent keratometry or IOLMaster 700 kera¬tometry for IOL power calculation. Int Ophthalmol. 2021; 41(6): 2205-12. https://doi.org/10.1007/s10792-021-01781-6
3. 4.Symes RJ, Ursell PG. Automated keratometry in routine cataract surgery: comparison of Scheimpflug and conventional values. J Cataract Refract Surg. 2011; 37(2): 295-301. https://doi.org/10.1016/j.jcrs.2010.08.050
4. 5.Woodmass J, Rocha G. A comparison of Scheimpflug imaging simulated and Holladay equivalent keratometry values with partial coherence interfero¬metry keratometry measurements in phakic eyes. Can J Ophthalmol. 2009; 44(6): 700-4. https://doi.org/10.3129/i09-172
5. 6.Symes RJ, Say MJ, Ursell PG. Scheimpflug keratometry versus conventional automated keratometry in routine cataract surgery. J Cataract Refract Surg. 2010; 36(7): 1107-14. https://doi.org/10.1016/j.jcrs.2009.11.026 7.Kheirkhah A, Safi H, Nazari R, et al. Effects of pterygium surgery on front and back corneal surfaces and anterior segment parameters. Int Ophthalmol. 2012; 32(3): 251-7. https://doi.org/10.1007/s10792-012-9560-2 8.Levinger E, Sorkin N, Sella S, et al. Posterior Corneal Surface Changes After Pterygium Excision Surgery. Cornea. 2020; 39(7): 823-6. https://doi.org/10.1097/ICO.0000000000002325
6. 9.Kheirkhah A, Safi H, Molaei S, et al. Effects of pterygium surgery on front and back corneal astigmatism. Can J Ophthalmol. 2012; 47(5): 423-8. https://doi.org/10.1016/j.jcjo.2012.07.002
7. 10.O’Dwyer PA, Akova YA. Temel Göz Hastalıkları. 3rd ed., İstanbul, Güneş Tıp Kitabevleri, 2015.
8. 11.Saraç Ö. Pratik Kornea Topografisi. 1st ed., Ankara, Anadolu Kitabevi, 2022.

9. 12.Cinal A, Yasar T, Demirok A, et al. The effect of pterygium surgery on cor¬neal topography. Ophthalmic Surg Lasers. 2001; 32(1): 35-40.
10. 13.Ozdemir M, Cinal A. Early and late effects of pterygium surgery on corneal topography. Ophthalmic Surg Lasers Imaging. 2005; 36(6): 451-6.
11. 14.Maheshwari S. Pterygium-induced corneal refractive changes. Indian J Ophthalmol. 2007; 55(5): 383-6. https://doi.org/10.4103/0301-4738.33829
12. 15.Yilmaz S, Yuksel T, Maden A. Corneal topographic changes after four types of pterygium surgery. J Refract Surg. 2008; 24(2): 160-5. https://doi.org/10.3928/1081597X-20080201-06
13. 16.Errais K, Bouden J, Mili-Boussen I, et al. Effect of pterygium surgery on corneal topography. Eur J Ophthalmol. 2008; 18(2): 177-81. https://doi.org/10.1177/112067210801800203 17.Oh JY, Wee WR. The effect of pterygium surgery on contrast sensitivity and corneal topographic changes. Clin Ophthalmol. 2010; 4: 315-9. https://doi.org/10.2147/opth.s9870
14. 18.Yasar T, Ozdemir M, Cinal A, et al. Effects of fibrovascular traction and po¬oling of tears on corneal topographic changes induced by pterygium. Eye (Lond). 2003; 17(4): 492-6. https://doi.org/10.1038/sj.eye.6700377
15. 19.Saglik A, Celik H, Aksoy M. An Analysis of Scheimpflug Holladay-Equiva-lent Keratometry Readings Following Corneal Collagen Cross-Linking. Be-yoglu Eye J. 2019; 4(2): 62-8. https://doi.org/10.14744/bej.2019.35220
16. 20.Achiron A, Elhaddad O, Leadbetter D, et al. Intraocular lens power calcu¬lation in patients with irregular astigmatism. Graefes Arch Clin Exp Ophthal¬mol. 2022; 260(12): 3889-95. https://doi.org/10.1007/s00417-022-05729-z