Cataract Surgery in the Patient with a History of LASIK or PRK #56996-RS April 2018 Sebastian Lesniak, MD Matossian Eye Associates
None Disclosures
Bio Matossian Eye Associates, Hopewell NJ, 7/2015 Present Fellowship: Wills Eye Hospital, Anterior Segment and Cornea, 7/2014 6/2015 Residency: New Jersey Medical School, Rutgers University, Ophthalmology Residency Program. 7/2011 6/2014 Internship: Robert Wood Johnson Medical School, Rutgers University, Internal Medicine, 7/2010 6/2011 Medical School: Robert Wood Johnson Medical School, Rutgers University, 8/2006 5/2010 Master s Degree: University of Pennsylvania, 1/2003 12/2004 Bachelor s Degree: Rutgers University School of Engineering, Mechanical Engineering, 9/1997 5/2001
Radial Keratotomy Hyperopic drift over time and diurnal fluctuations Perform IOL measurements in the morning and in the afternoon Aim for low myopia Avoid multifocal IOLs Wait 3 months before considering IOL exchange Avoid intersection with RK incisions when creating phaco wounds Consider scleral incision
Radial Keratotomy Phaco incisions can cause additional instability
Photorefractive Keratectomy (PRK) Obtain careful history Request records including pre-prk K s and refraction Refraction prior to the onset of the cataract Assess the risk of ectasia determine if the myopic shift is from the cataract vs ectasia
Laser In-Situ Keratomileusis (LASIK) Similar to post-prk Obtain careful history, records etc. Maximize ocular surface, pre-treat if necessary Inspect the flap for epithelial ingrowth which may cause irregular astigmatism
Post Refractive Corneal Curvature Masket S. et al. J Cataract Refract Surg 2006; 32:430 434.
Traditional IOL Calculation IOL formulas assume that the curvature and relationship between anterior and posterior corneal surfaces are normal
Corneal Topography Curvature measurement of the surface Relies on reflected light from the front (anterior) of the cornea
The Challenge of Post Refractive IOL Calculation Topographers measure the anterior surface only Normal relationship between anterior and posterior corneal surfaces is assumed Total corneal power is calculated based on the measured anterior corneal surface and standard keratometric index
Post Refractive IOL Calculation Photoablative procedures such as LASIK and PRK change the relationship between the anterior and posterior surfaces Myopic Ablation Hyperopic Ablation Over-estimation of Corneal Power Lower IOL Power Selected Hyperopic Surprise Under-estimation of Corneal Power Higher IOL Power Selected Myopic Surprise
The Challenge of Post Refractive IOL Calculation Effective Lens Position (ELP) is calculated based on K s Anterior Chamber Depth (ACD) does not change after refractive surgery Effective Lens Position Underestimated Lower IOL Power selected Hyperopic Surprise in Myopic Ablations
The Challenge of Post Refractive IOL Calculation Standard measurements and calculations result in: Hyperopic surprise in previously myopic patients Myopic surprise in previously hyperopic patients
Historical Post Refractive IOL Calculation Methods Clinical History Method Preop K s and refraction (SEQ) Kpostop = Kpreop ( SEQpostop SEQpreop ) Double K Method Preop K s for calculation of ELP Postop K s for the vergence formula for IOL Power Contact Lens Over-Refraction Method Kpostop = BC + P + (ORx MRx)
Corneal Tomography 3D representation of the cornea, think of a CT scan (computed tomography) Measures the front (anterior) and the back (posterior) shape of the cornea
Corneal Tomography Optovue Avanti uses OCT for Total Corneal Power Measurement
Corneal Tomography Oculus Pentacam uses slit illumination system and a Scheimpflug camera, which rotate together around the eye
Post Refractive Calculator http://iolcalc.ascrs.org/
Post RK Calculator
Post LASIK/PRK Calculator
Post LASIK/PRK Calculator
104 eyes Previous myopic LASIK/PRK Comparison of OCT, True-K No History, Wang-Koch- Maloney, Shammas, Haigis- L, and Average of these 5 formulas OCT and Average had the smallest prediction errors Wang et al. Ophthalmology 2015.
Intraoperative Aberrometry ORA by Alcon HOLOS by Clarity Medical Systems
ORA IOP Check
ORA IOL Selection
ORA Toric IOL Position Verification
246 eyes Prior Myopic LASIK/PRK ORA achieved the greatest predictive accuracy median absolute error of 0.35 D 67% of eyes were within 0.5 D significantly more accurate than the other methods: surgeon best choice, Haigis L method, and Shammas method Ianchulev et al. Ophthalmology 2014.
39 eyes without historical data 20 eyes with historical data No statistically significant difference among the methods: Masket regression formula, Haigis-L formula, ORA, Optovue OCT. Fram et al. Ophthalmology 2015.
Post Refractive CEIOL Case 63 y/o F Va: 20/30 OU s/p myopic LASIK OU Complains of Glare From Headlights While Driving at Night in OD Fuch s Dystrophy Pseudophakia OS Cataract OD 2+ Nuclear Sclerosis 1+ Cortical Changes Trace Posterior Subcapsular
Post Refractive CEIOL Case
Fuch s Dystrophy Typical Safe Levels in Fuch s Patients Cell Count >1000 cells/mm 2 Pachymetry <650 µm
Post Refractive CEIOL Case Pre-Op Specular Microscopy Pachymetry: 492 OD, 557 OS No complaints of fluctuating Va throughout the day
Post Refractive CEIOL Case
New IOL Master 700 Laser Vision Correction Mode for post-lasik Patients
New IOL Master 700
New IOL Master 700 DSEK usually causes a hyperopic shift of about 0.5 D Aim for -0.50 to -0.75 D in anticipation of future DSEK
Post Refractive CEIOL Case
Post Refractive CEIOL Case IOL calculations with LVC mode on the IOL Master Post-LASIK calculator ORA used intraoperatively Implanted 21.0 D Tecnis PCB00 IOL Patient reported significant improvement in subjective clarity of vision Post-Op Day#1 Uncorrected Va 20/30-2 Mrx: Plano -1.25 x 95 = 20/30, J1 Spherical Equivalent = -0.625
Summary Carefully educate the patient about the unpredictability of refractive outcome Set realistic expectations Obtain previous records Use the ASCRS Online Post-Refractive IOL Power calculator for all post-refractive patients Utilize the Laser Vision Correction Mode on IOL Master 700 Use ORA if available Avoid hyperopic surprises by aiming for low myopia
References http://www.apacrs.org/barrett_true_k_universal_2 http://iolcalc.ascrs.org Essentials of Cataract Surgery. Bonnie An Henderson Ed. Slack Incorporated. 2007. Refractive Surgery. BCSC Section 13. AAO. 2011. Refractive Lens Exchange. Ming X. Wang Ed. Slack Incorporated. 2016. Masket S. et al. Simple regression formula for intraocular lens power adjustment in eyes requireing cataract surgery afer excimer laser photoablation. J Cataract Refract Surg. 2006. Wang L. et al. Comparison of Newer Intraocular Lens Power Calculation Methods for Eyes after Corneal Refractive Surgery. Ophthalmology. 2015. Ianchulev T. et al. Intraoperative Refractive Biometry for Predicting Intraocular Lens Power Calculation after Prior Myopic Refractive Surgery. Ophthalmology. 2014. Fram N. et al. Comparison of Intraoperative Aberrometry, OCT- Based IOL Formula, Haigis-L, and Masket Formulae for IOL Power Calculation after Laser Vision Correction. Ophthalmology. 2015.
Thank you Sebastian Lesniak, MD Matossian Eye Associates www.matossianeye.com