Ray T. Oyakawa, M.D., M.B.A. ASCRS Boston 2010 No financial interests Vector Analysis for Astigmatism Management in Cataract Surgery

Purpose  To present the results of two prospective overlapping studies:  Main Study: Vector-Adjusted Nichamin Age Pachymeter Adjusted (NAPA) Limbal Relaxing Incisions(LRIs) at the time of cataract surgery.  Subset Study: Incision Location Adjustment (ILA) in presbyopia correcting cataract surgery to reduce the number of LRIs.  Background:  The main study above (Oyakawa, Poster # P73, ASCRS Chicago 2008) has evolved into the use of Vector Analysis for Astigmatism Management in Cataract Surgery incorporating Incision Location adjustment (ILA).

Methods All patients having LRIs and patients having presbyopic correcting IOLs had vector analysis of astigmatism with the AcryosofToricCalculator using the IOLMaster keratometry readings. Keratometry readings from corneal topography, auto refractor, and IOL Master were compared Surgically Induced Astigmatism (SIA) calculations refined over time. 1 st 13 eyes 0.5 D Next 15 eyes 0.3 D Currently 0.4 D SIA calculator hill.com/physicians/download.htm

ILAs can obviate the need for LRIs Methods Astigmatism reduction from 1.28 D to 0.71D

Methods Peripheral corneal thicknesses were measured with the Palmscan using a 50MHz probe at the slit lamp by the author while a tech managed the Palmscan in eyes which the AcrySofToric calculator determined an astigmatism of >0.50 D A 10 MHz probe will not work. The DGH with a 20 MHz probe will work The Palmscan built in Vector NAPA concurrent cataract program was used to determine 90% depth of the thinnest corneal thickness in the arc of the LRI This can be done by using the AcrysofToricCalculator as a guide to pachymetry and the NAPA nomogram.

Patient Demos 70 consecutive LRIs concurrent with cataract surgery were done from 3/16/07 to 1/28/10. The first 63 cases were done by the author and the last 4 cases were done by Dr. David J. Fuerst. 3 cases not included: 1 inadequate f/u 1 error in execution of LRI 1 LRI w/Toric for 5D of corneal astigmatism reduced to 1.25 D then enhanced 67 eyes of 52 patients are the basis of the main study, 22 females and 30 males, average age 69, range 44 to AT50/52AO, 39 AT50/52SE, 18 HD500/520, 2 NXG1, 2 ZCBOO, 1 ZMA00, 1 LI61AO Subset study: Vector analysis was used in 48 consecutive presbyopia correcting IOLs, 44 cases by the author and 4 cases by Dr. Fuerst to manage astigmatism by ILA from 11/08 through 2/10. LRIs were used in cases where ILA would not decrease astigmatism to <0.75 D. 24 patients, 7 females, 17 males, average age 71, range 55 to 83.

Preop Astigmatism (diopters) in LRI cases 47 eyes WTR astigmatism (Not vector adjusted) Temporal incision increases WTR astigmatism 20 eyes ATR astigmatism (Not vector adjusted) Temporal incision decreases ATR astigmatism

Blade Depth and Arcs 62 paired arcs (25 to 80 deg) 5 single arcs (80 to 90 deg-2x NAPA) 4/5 of single arcs for ATR astigmatism to avoid LRI arc in phaco wound

Surgical Technique Pre-op corneal marks with the patient sitting up were used infrequently. LRIs were done prior to entering the eye. Various markers and ring guides were used: Dell Marker, Mendez gauge, Mastel Gimbel Mendez Marker and Mastel Jarvis Olsen Ring Storz Oyakawa LRI marker guide (prototype), Storz Oyakawa Micrometer adjusted LRI blade, Master Elite II Micrometer adjusted LRI blade Bimanual-MICS 19 g. with Infinity Ozil using a Master Sidewinder tip ( reverse and standard Kelman). 58 eyes had the wound enlarged to 3.1mm, 3 eyes to 2.0, 2.1, 2.4 mm to insert the IOL. 2 eyes for ZCB00 had the wound enlarged to 2.2 mm. ILAs had one of the bimanual incisions located at the ILA site and this was enlarged for the IOL. 2.2 mm 20 g. Infinity Ozil –Dr. Fuerst. Wound enlarged to 3.0 mm-4 eyes. The phaco incision site was located at the ILA and then enlarged for the IOL insertion. Topical and intracameral ( Cionni, Epishugarcaine with & without BSS+) anesthesia.

Results Micro monovision target -.50 to -.75 Refractive astigmatism Ave D, range 0 to 1.00 Average f/u 185 days, range 33 to 784 days Micro monovision target -.50 to -.75 Refractive astigmatism Ave D, range 0 to 0.75 Average f/u 134 days, range 22 to 266 days

Results Before ILAs, 123 presbyopia correcting IOLs were implanted. LRIs were done in 46% of cases. After ILAs, LRIs were done in 25%. 1 enhancement for 1.25 D of residual astigmatism, initial treatment for 1.63 D of astigmatism-case # 4. 66/67 – 98.5% success. 1 micro perforation (blade depth 646)- case # 25. Did not affect phaco, UCVA 20/20 1 extension of phaco wound into LRI (Pair 80 degree arc for 4 D- sutured) UCVA 20/30+, plano -.50 x32=20/20-2

Conclusions Vector adjusted ILAs or NAPA LRIs are effective in reducing astigmatism. Incision location can sufficiently reduce astigmatism in 75% of cases of presbyopia correcting IOLs. LRIs are needed in only 25%. ILAs are effective in eyes with up to about 1.25 diopters of astigmatism and can reduce the need for LRIs from 46% to 25%. Vector adjusted, NAPA LRIs done concurrently with cataract extraction are 98.5% effective and safe in treating preoperative astigmatism. We learned in the RK days that 90% depth incision was needed for good effect. This is probably true for LRIs. 29% of LRI incision depths >650 microns. 2% of LRI incision depths <550 microns. Fixed depth 600 micron blade may have perforated the cornea in some of these eyes. A fixed depth 600 micron LRI blade would probably be OK in 69% of arcs. Peripheral corneal thickness measurement should be done for safety when using a 600 microns fixed depth LRI blade.