Abstract
Purpose: :
To assess the changes in ocular aberrations, accommodative response function and accommodative facility following laser refractive surgery for myopia.
Methods: :
Accommodative response and accommodative facility measurements were obtained pre-operatively and then at one month and three months after LASIK/LASEK in 31 subjects (mean age: 32.0 ± 6.2 years) with refractive error ranging from -1.25D to -9.75D. Higher order ocular aberrations were measured over a 5mm pupil. Stimulus-response functions were measured for 0.25D, 1.00D, 2.00D, 3.00D and 4.00D stimuli. Monocular accommodative facility for the viewing eye was investigated at 4.0m and 0.4m.
Results: :
RMS of higher order aberrations (3rd to 6th order) increased from pre-operative values of 0.16 ± 0.05µm to 0.32 ± 0.15µm at the one month post operative visit and changed to 0.23 ± 0.07µm at the three month post-operative visit (F2, 28 = 20, p = 0.001). The majority of participants showed changes in spherical aberration of the order of 0.05µm or more. Following surgery, significant alterations to accommodative functions were found. A significant reduction in accommodative response slope over time (F2, 28 = 6.532, p = 0.003) was seen and distance facility rate increased by approximately 2-3 cycles/minute at three months (p=0.008). At three months, a significant correlation was found between the change in accommodative stimulus-response function gradient, and the change in spherical aberration following surgery (Pearson’s correlation coefficient = -0.56, p=0.002).
Conclusions: :
The results suggest that corneal laser refractive surgery can have an impact on components of the accommodative response, and that alterations to higher order aberrations may contribute to the changes in accommodative function.
Keywords: accommodation • refractive surgery: LASIK