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New Technology

Surface Ablation With Iris Recognition and Dynamic Rotational Eye Tracking–based Tissue Saving Treatment With the Technolas 217z Excimer Laser

Gaurav Prakash, MD; Amar Agarwal, MS, FRCS, FRCOphth; Dhivya Ashok Kumar, MD; Soosan Jacob, MS, FRCS, DNB; Athiya Agarwal, MD, DO; Amrita Maity, BOptom

PURPOSE

To evaluate the visual and refractive outcomes and expected benefits of Tissue Saving Treatment algorithm–guided surface ablation with iris recognition and dynamic rotational eye tracking.

METHODS

This prospective, interventional case series comprised 122 eyes (70 patients). Pre- and postoperative assessment included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction, and higher order aberrations. All patients underwent Tissue Saving Treatment algorithm–guided surface ablation with iris recognition and dynamic rotational eye tracking using the Technolas 217z 100-Hz excimer platform (Technolas Perfect Vision GmbH). Follow-up was performed up to 6 months postoperatively. Theoretical benefit analysis was performed to evaluate the algorithm’s outcomes compared to others.

RESULTS

Preoperative spherocylindrical power was sphere –3.62±1.60 diopters (D) (range: 0 to –6.75 D), cylinder –1.15±1.00 D (range: 0 to –3.50 D), and spherical equivalent –4.19±1.60 D (range: –7.75 to –2.00 D). At 6 months, 91% (111/122) of eyes were within ±0.50 D of attempted correction. Postoperative UDVA was comparable to preoperative CDVA at 1 month (P=.47) and progressively improved at 6 months (P=.004). Two eyes lost one line of CDVA at 6 months. Theoretical benefit analysis revealed that of 101 eyes with astigmatism, 29 would have had cyclotorsion-induced astigmatism of >10% if iris recognition and dynamic rotational eye tracking were not used. Furthermore, the mean percentage decrease in maximum depth of ablation by using the Tissue Saving Treatment was 11.8±2.9% over Aspheric, 17.8±6.2% over Personalized, and 18.2±2.8% over Planoscan algorithms.

CONCLUSIONS

Tissue saving surface ablation with iris recognition and dynamic rotational eye tracking was safe and effective in this series of eyes. [J Refract Surg. 2011;27(3):223-231.]

doi:10.3928/1081597X-20100428-01

AUTHORS

From Dr Agarwal’s Eye Hospital and Eye Research Centre, Chennai, India.

Prof Amar Agarwal is a paid consultant to Abbott Medical Optics, Santa Ana, California and Bausch & Lomb, Rochester, New York. The remaining authors have no financial or proprietary interest in the materials presented herein.

Correspondence: Amar Agarwal, MS, FRCS, FRCOphth, Dr Agarwal’s Eye Hospital and Eye Research Centre, 19 Cathedral Rd, Chennai 600 086, India. Tel: 91 44 2811 6233; Fax: 91 44 2811 5871; E-mail: dragarwal@vsnl.com

Received: August 6, 2009; Accepted: March 30, 2010

Posted online: May 3, 2010