Double Trouble! : Cataract Surgery Post Double Refractive Surgery; How Biometry Saved The Day.

To discuss IOL power calculation in a double refractive surgery eye i.e Post LASIK and post phakic IOL implantation.

Interventional case report. Advanced Eye Center

A 40-year-old male complained of gradually progressive blurring of vision in his right eye for one year. He gave history of low vision in his right eye since childhood.  He underwent bilateral laser-assisted keratomileusis (LASIK) 20 years ago, followed by a right eye implantable phakic intraocular lens (phakic -IOL) done for residual refractive error in the right eye around ten years later.  The best corrected visual acuity (BCVA) was 6/60 in the right eye (-4.5-DS and -2DC at 120) and 6/9 (-4DS) in the left eye. The right eye showed an anterior subcapsular cataract involving the visual axis cataract. The axial length in the right eye was 34.42 mm, and the left eye was 28.21mm. Biometry was done using IOL master 700 with Phakic IOL mode. Using Barett's true K formula and ASCRS post-online refractive formulae, a +8 D  IOL was implanted after IPCL explantation and cataract removal. His postoperative BCVA was 6/18 with only +0.75 diopters cyl at 50 error. 

 In our case, the challenge was IOL power calculation in eye post, both LASIK and phakic-IOL. The anterior and posterior corneal surface ratio changes after LASIK surgery, making it challenging to estimate corneal power. Moreover, the anterior surface of the Phakic -IOL is usually mistakenly recognized as the crystalline lens, leading to an underestimation of the ACD and an overestimation of the LT. We suggest using Barrett's true K and ASCRS online formulas and noting the swept source OCT image to see if Phakic -IOL is not mistaken as an anterior lens surface. Hence, accurate biometry is essential to avoid any post-operative refractive surprises in cataract surgery cases post multiple refractive procedures.