Purchase this article with an account.
G. Hollo, M. Toth; Advanced Scanning Algorithm (ASA) in Scanning Laser Polarimetry: Advantage Over Variable Corneal Compensation (VCC) in a Human LASIK Model . Invest. Ophthalmol. Vis. Sci. 2005;46(13):2500.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate the potential advantages of an advanced scanning algorithm (ASA) over variable corneal compensation (VCC) in scanning laser polarimetry. Methods: One eye of 15 healthy ametropic subjects was imaged immediately before and 7 days after uncomplicated LASIK surgery. An anterior segment birefringence image was taken at each measurement session. Pre– vs post–LASIK RNFL measures along the TSNIT plot were investigated. For post–LASIK RNFL measurements, both the pre–LASIK corneal retardation values were used for corneal compensation (VCC* and ASA*), as well as new post–LASIK corneal retardation values (VCC and ASA). Results: All eyes showed atypical RNFL patterns with VCC*, but none with ASA* after LASIK. In contrast to the fixed method, LASIK had no effect on RNFL measurements in VCC and ASA methods (ANOVA, P>0.05). In VCC* the LASIK induced RNFL change was significant (<0.01) in the temporal, superior and nasal sectors. In contrast, no effect was seen in ASA* (p>0.05 for each sector). The number of significantly altered points along the TSNIT plot was significantly higher in the fixed method than either in VCC or ASA (binomial test, P<0.001). No difference was found between VCC and ASA, VCC and ASA*, and ASA and ASA* (P>0.05). Significantly more points were altered in VCC* than either in VCC or ASA* (P<0.001). Conclusions: The new ASA compensation method is more effective than VCC in neutralization of the LASIK–induced atypical RNFL measurements. This suggests that ASA may improve the clinical value of polarimetry when atypical RNFL measurements are present in the eye.
This PDF is available to Subscribers Only