Ray-Tracing Wavefront Analysis and Biometric Findings After Laser Anterior Ciliary Excision Procedure
Purpose
To evaluate serial measurements of dynamic changes of higher-order aberrations and depth of focus by ray-tracing aberrometer as well as biometric findings pre and post Laser Anterior Ciliary Excision (LaserACE) procedure.
Methods
A 2.94um Er:YAG is used to perform partial-thickness micro-ablations in the sclera in three critical anatomic zones to reduce ocular rigidity and to restore natural accommodative function. Dynamic wavefront analysis and UBM biometry (Sonomed,VuMax) measurements were performed on 20 eyes of 10 patients. UBM Biometry was performed on all patients in anterior segment measuring accommodative structures. A Ray-tracing aberrometer was used to objectively measure the dynamic visual range preoperatively and at 1 week, 1 month and 3 months after LaserACE treatment. The range of accommodation in diopters for each eye and the dynamic changes in defocus, spherical aberration, coma and trefoil were recorded. Data from 3 patients who received ray-tracing aberrometer evaluations to measure the preserved accommodative range postoperatively at 5yrs, 6yrs and 8yrs is presented.
Results
Dynamic wavefront analysis and UBM biometry measurements were performed on 20 eyes of 10 patients. UBM measurements showed changes in accommodative biomechanics postoperatively. The visual acuity of the subjects were also measured for distance, intermediate (60cm) and near (40cm) both in uncorrected and best-corrected methods showed an improvement of 2-4 lines. There was no statistical change in UDVA or CDVA (p<0.01). The accommodative range increased 1.25-1.5D (p<0.034) after the LaserACE treatment. Changes in SA, Coma, Trefoil, and defocus during dynamic accommodation were noted.
Conclusion
Ray-tracing technology can objectively measure dynamic accommodation and is a critical device to differentiate true accommodation from pseudoaccommodation. Changes after LaserACE procedure were seen in both spherical aberration and depth of focus. Pseudoaccommodation from changes in spherical aberration and increased depth of focus may contribute to near vision functionality. Biometric evidence shows physiological changes after the LaserACE procedure which may explain some of the effects of the procedure.