Importance Of Corneal Spherical Aberration Of Pupil Area For Multifocal Iol Selection: A Case Report

To report a case where, despite the normal range of the total HOAs (4mm zone) and spherical aberration (SA) (6mm zone) of the cornea, the corrected visual acuity after implantation of an extended depth of focus (EDOF) IOL became
lower than before surgery.

Retrospective single case report, First Samsung Eye Center, Seoul, Republic Of Korea

A patient who had undergone LASIK got an extended depth of focus intraocular lens implantation(VivityTM, Alcon Inc.) to treat cataracts. It seemed that there were no specific findings in the routine preoperative examination. However, the patient complained of blurring postoperatively. The best-corrected visual acuity decreased to 20/40 (20/32 x -0.25Dsph=-0.25Dcyl x 10) compared to before the surgery 20/32 (20/20 x +0.5Dsph). After reviewing the preop exam results, it was confirmed that the anterior corneal SAs between the 2~4mm zone were negative. But, primary corneal SA (6 mm zone) and total higher-order aberration (HOA) (4 mm zone) were in the normal range (0.155 μm and 0.150 μm, respectively). To modify the aberration of the corneal center, topography-guided ablation after flap lifting was performed, which resulted in the SA changing into the positive. Finally, uncorrected visual acuity became 20/20 at postopo 1m. 

: In conclusion, the interaction between corneal SA and the asphericity of MIOL can produce a serious problem in atypical corneas. Furthermore, verifying corneal SA from the paraxial zone to the periphery is much safer than using a single SA only. We have tools that can identify corneal HOAs. However, the knowledge to predict the adverse effects of HOA is still insufficient. Furthermore, as the frequency of cataract surgery in patients who have undergone corneal refractive surgery increases, diagnosing irregular corneal astigmatism and understanding its related symptoms and treatment is becoming more critical. Therefore, it is necessary to achieve a breakthrough in this field through additional research.