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Abstract #18206 Published in IGR 9-2
Assessment of the nerve fiber layer thickness after LASIK using scanning laser polarimetry with variable corneal compensation
Abitbol O; Duong MH; Hoang-Xuan T; Gatinel D; Lachkar YJournal Français d'Ophtalmologie 2007; 30: 503-509
AIM: To evaluate the reliability of scanning laser polarimetry with variable corneal compensation after laser-assisted in-situ keratomileusis (LASIK). METHODS: Thirty-six eyes of 18 consecutive patients who had LASIK where included in the study. For each eye, one scanning laser polarimetry with variable corneal compensation (GDxVCC) was performed before LASIK (GDx no 1). One month after surgery, two other scanning laser polarimetry procedures were performed: one used the corneal compensation measured preoperatively (GDx no 2) and one used a new corneal compensation, measured postoperatively (GDx no 3). The values measured preoperatively were compared first to the values obtained postoperatively with GDx no 2, then to the values obtained postoperatively with GDx no 3 (Wilcoxon test). RESULTS: When corneal compensation was re-measured postoperatively (GDx no 3), the measurements were reliable for 35 eyes (97%). We found no significant differences between the preoperative and postoperative values except for the NFI (p = 0.032). When the preoperative corneal compensation value was used in the postoperative measurements (GDx no 2), the exam was not reliable for 13 eyes, and it could not be performed at all for two eyes. For the remaining eyes, the values of four parameters were significantly modified: superior thickness (p = 0.03), superior ratio (p = 0.0005), inferior ratio (p = 0.009), and ellipse modulation (p = 0.39). The values of the other parameters (average thickness and inferior average) remained unchanged. CONCLUSION: The use of a preoperative customized corneal compensation for the realization of post-LASIK measurements does not provide reliable results. The GDxTMVCC can be considered a reliable tool after LASIK only when the corneal compensation is re-evaluated postoperatively. LA: French
Dr. O. Abitbol, Fondation Ophtalmologique Adolphe de Rothschild, Paris, France. oliviaabitbol@free.fr
Classification:
8.4 Refractive surgical procedures (Part of: 8 Refractive errors in relation to glaucoma)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)
6.9.1.2 Confocal Scanning Laser Polarimetry (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)