Clinical analysis of central islands after laser in situ keratomileusis

Purpose: To analyze the incidence and clinical characteristics of central i slands after laser in situ keratomileusis (LASIK) and to elucidate factors associated with their formation. Setting: Samsung Medical Center, Sungkyunkwan University School of Medicine , Seoul, Korea. Methods: Laser in situ keratomileusis was performed in 103 eyes of 61 patie nts with myopia ranging from -4.0 to -13.5 diopters (D) using the Hansatome (R) (Chiron) and SVS Apex Plus(R) (version 3.2.1) excimer laser (Summit Tec hnology) in which the anticentral-island program was implemented. After 1 w eek, corneal topography (Orbscan(R), Orbtek) was done and manifest refracti on and visual acuity were measured. Results: Postoperatively, the mean uncorrected visual acuity (UCVA) and bes t corrected visual acuity (BCVA) were 0.12 and 0.06 (logMAR scale), respect ively, and the mean refractive error (spherical equivalent) was 0.07 D +/- 0.76 (SD). On topographic examination, a central island was defined as an a rea of higher refractive power of more than 1.5 D and 2.5 mm or more in dia meter, Budding or isolated central islands were observed in 12 eyes of 12 p atients (11.7%). The peak, height, and area of the islands were 41.5 +/- 3. 1 D, 5.6 +/- 1.9 D, and 3.5 +/- 1.1 mm(2), respectively. In the eyes with c entral islands, there were statistically significant differences in the pos toperative change in UCVA and BCVA (P < .05). There was no significant corr elation between the occurrence of a central island and preoperative refract ive error, corneal thickness, age, or in sex and correction of astigmatism (P > .05). Conclusion: Despite use of the anti-central-island pretreatment program, th e occurrence of central islands after LASIK was significant, as in photoref ractive keratectomy. Further studies of the effect of central islands on su rgical results and clinical progress and measures to prevent the occurrence are needed. J Cataract Refract Surg 2000; 26:536-542 (C) 2000 ASCRS and ES CRS.