In their article,1 Mian et al. introduced planned combination of intrastromal corneal ring segment (ICRS) insertion and laser in situ keratomileusis (LASIK) as an effective modality to reduce ablation depth and subsequently save more residual corneal stroma. However, there are some pitfalls in their article.
First, even though LASIK and ICRS insertion are approved by the U.S. Food and Drug Administration (FDA) as separate procedures,2 planned combination of them has not been approved for correction of high myopia.3
Second, the authors state in their introduction that both LASIK and ICRS have the additive effect of inducing central corneal flattening by different mechanisms; however, it should be mentioned that ICRS insertion will maintain the cornea's inherent positive asphericity, whereas LASIK yields an oblate postoperative pattern.3
Third, only 41% of their patients achieved uncorrected visual acuity of 20/40 or better, which is much lower than that after implantation of phakic intraocular lenses (IOLs)4; hence, the entire procedure is not as appropriate as they claim.
Fourth, in 3 eyes (20%) (cases 3, 7, and 8), only the intended LASIK correction has been corrected (and not the preoperative manifest refraction–intended total correction), and it seems that ICRS insertion has not played an effective role in decreasing myopia in these eyes. Hence, the ICRS role may be unpredictable when inserted simultaneously during LASIK.
Fifth, the follow-up period is too short (1 month in 2 cases and 12 months in the others) to conclude that “this procedure is good for correction of high myopia,” as stated by the authors. Safety and effectiveness of new interventions should be evaluated by longer follow-up periods and a larger sample size.5
Sixth, if for any reason the surgeon decides to remove the ICRS, it seems more difficult in practice owing to the overlying LASIK flap.
Simultaneous LASIK and ICRS insertion does not yield predictable outcomes nor is it cost effective for patients. Implantation of phakic IOLs may be a better choice for patients with high myopia provided the anterior chamber depth is adequate.
REFERENCES
1. Mian SI, Jarade EF, Scally A, Azar DT. Combined ICRS insertion and LASIK to maximize postoperative residual bed thickness in high myopia. J Cataract Refract Surg. 2004;30:2383-2390.
2. Barbara A, Shehadeh-Masha'our R, Garzozi HJ. Intacs after laser in situ keratomileusis and photorefractive keratectomy. J Cataract Refract Surg. 2004;30:1892-1895.
3. American Academy of Ophthalmology. Basic and Clinical Science Course. Section 8: External Disease and Cornea. San Francisco, The Academy, 2002–2003; 470
4. Arne JL. Phakic intraocular lens implantation versus clear lens extraction in highly myopic eyes of 30- to 50-year-old patients. J Cataract Refract Surg. 2004;30:2092-2096.
5. Mohammadpour M. Safe and effective. In press, Ophthalmology
