Intraocular lens power calculation after excimer laser corneal refractive surgery: A retrospective study to compare the predictability and the efficacy of commonly used and modified formulas

Reeda B Said; Ralph Ghorayeb; Dany Akiki; Elias Wakim; Georges Sukkarieh; Joseph Sfeir; George Cherfan; Elias Jarade

doi:10.4103/sjopt.sjopt_185_21

Intraocular lens power calculation after excimer laser corneal refractive surgery: A retrospective study to compare the predictability and the efficacy of commonly used and modified formulas

Saudi J Ophthalmol. 2022 Aug 29;36(2):177-182. doi: 10.4103/sjopt.sjopt_185_21. eCollection 2022 Apr-Jun.

Authors

Reeda B Said^{1

2}, Ralph Ghorayeb³, Dany Akiki⁴, Elias Wakim⁴, Georges Sukkarieh^{2

3}, Joseph Sfeir⁴, George Cherfan^{1

2}, Elias Jarade^{1

2

5}

Affiliations

¹ Department of Ophthalmology, Faculty of Medicine, Lebanese University, Beirut, Lebanon.
² Beirut Eye and ENT Specialist Hospital, Beirut, Lebanon.
³ Hȏtel-Dieu de France Hospital, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon.
⁴ Department of Medicine, Faculty of Medicine, Lebanese University, Beirut, Lebanon.
⁵ Department of Ophthalmology, Mediclinic Dubai Mall, Dubai, United Arab Emirates.

Abstract

Purpose: Our article aims to assess the accuracy of modified and commonly used formulas of intraocular lens (IOL) power calculation after excimer laser corneal refractive surgery.

Methods: This is a retrospective study, with data retrieved for 50 eyes of 32 patients who underwent uncomplicated cataract surgery after excimer laser corneal refractive surgery. The expected spherical equivalent was calculated using the American Society of Cataract and Refractive Surgeons (ASCRS) IOL power calculator for Shammas and Barrett True-K, using three-fourth generation formulas (Haigis-L, Barrett True-K no history, and Holladay 2), and using three-third generation formulas (SRKT, Holladay 1, and Hoffer Q) with single k, as a reference, and adjusting these formulas by calculating the keratometry readings by two methods (Jarade's index and formula). The mean refractive error and mean absolute refractive error (MARE) were calculated at the 1 postoperative month.

Results: When all data was available (eight eyes), 13 formulas were compared. Holladay 1 as modified by Jarade's index and formula, and Hoffer Q as modified by Jarade's formula resulted in MARE <0.75D (P < 0.05). In the group of 25 eyes with only ablation available, the formulas with MARE <0.75D were Haigis L, Barrett TK (from ASCRS), Hoffer Q, and the three conventional formulas in Jarade's index (P < 0.001). In the group of 17 eyes with no available prerefractive data, only Haigis-L and Barret TK (no history) had a MARE <0.75 D.

Conclusion: The use of Hoffer Q or Holladay 1, when prerefractive data are available, gives reliable results with Jarade's index.

Keywords: Cataract; emmetropia; formulas; intraocular lens; laser-assisted in situ keratomileusis; refractive.