Photoablative cosmetic iridoplasty: effective, safe, and predictable—eye color change in 1176 eyes
Authors: Grimaldos Ruiz Pedro 
Published: January 2021

Abstract
Purpose
To evaluate photoablative cosmetic iridoplasty (PCI), and its efficacy, safety, predictability, and satisfaction with the 532 nm Crystal Q-switched Nd: Yag laser, with 3–4 ns pulses, for depigmentation of the anterior epithelium of the iris in cases of heterochromia, nevus, or cosmetic indications (eye color change).

Design
Prospective clinical study on efficacy, safety, predictability, and satisfaction.

Method
The selection of patients was carried out in healthy individuals, over 18 years of age, with iris heterochromia (congenital-7% or acquired, secondary to topical medication-1%, trauma-0.5% or surgery-0.25%), nevus-0.25% and cosmetic cases-91%. Data were collected independently by assistant optometrists and classified in database. Excel statistical program was used to perform a general descriptive study, calculation of correlation factors, and statistical significance analysis between quantitative variables (Student T Test). PCI was performed in 1176 eyes of 588 patients. The procedures were planned in 2–3 phases of 4 consecutive sessions spaced 4–6 months apart. The IRÎZ® (Eyecos®) scanner was used to evaluate the cases, with photography, optical coherence tomography, and pneumotonography modules, along with the following software programs: Predictor®, Simulator® 3D, Analyzer® and Planner® (Eyecos®).

Results
This study began in 2012, so far 9 years of follow-up, to compare and choose the most suitable among 4 types of lasers to perform cosmetic iridoplasty. Finally, after 5 years, the Crystal Q-switched Nd: Yag at double frequency (532 nm) with 3–4 ns pulses demonstrated the highest efficacy, safety and predictability, so since early 2017 only this equipment has been used. Significant differences were found after 5-year follow-up between 1064, 532, 577 and 532/3–4 ns p = 0.09172, 0.06377 and 0.10183. From 9 January 2017 to 28 February 2020, 1176 eyes have been treated in 588 patients, with a mean age of 33.7 years (SD = 9.68 years, range = 18–70 years). 46.2% were male, and 53.7% were female. The efficacy, as quantified with the Analyzer® comparison software, was nearly 87–95%. There were no significant differences in corrected vision (9 years total follow-up p = 0.78235; last 4 years FU p = 0.99999) and ocular pressure (9 years total FU p = 0.68251; last 4 years FU p = 0.63204) before and after the procedure. The only notable complications (25%) were delayed and brief iritis, which were self-limited with routine topical treatment. The predictability was 80–90%. In the lightest-colored eyes, turquoise blue colors were obtained as a rule, in varying brightness; and in the darkest ones, gray blue tones of varying lightness. The patients’ subjective satisfaction at the end of treatment was 95%.

Conclusion
After 9 years of uninterrupted follow-up, PCI has demonstrated a high effectiveness to selectively depigment superficial melanin of iris, with a high predictability and patient satisfaction, without remarkable long-term complications. Only for a week, appropriate pre- and postoperative medication was necessary to guarantee the absence of discomfort, thus confirming security. PCI is effective, safe, and predictable for the treatment of pigmentary disorders in the iris and for the elective cosmetic indications in eye color change.