Abstract
Purpose: :
Although LASIK apparently does not result the degree of haze that sometimes follows PRK, some patients still complain of problems that could be due to increased light scattering. Micro–striae or other irregularities introduced by cutting the flap are possible sources of scattering that could be responsible for these complaints. The purpose of this study is to obtain objective measurements of backscattered light and ultimately determine if complaints are associated with greater levels of scattering.
Methods: :
Wavescan LASIK treatments were performed following flap cutting with the Intralase femtosecond laser. Scatterometer measurements were made prior to treatment, one day post–treatment, and two months post–treatment. Scatterometer measurements are referenced to scattering from optical grade Spectralon. [Braunstein et al, Ophthalmol. 103, 439–443 (1996)] A scattering index (SI) is calculated as the ratio of the normalized scattering to the average scattering from the normal corneas of 10 individuals. An SI = 1 represents normal scattering.
Results: :
Preliminary results from an ongoing study are being reported. Scattering increased one day post–treatment and receded to normal at two months. The average SI on day post–treatment was 4.3 OD (4 eyes) and 6.3 OS (5 eyes). At two months the average SI was 0.74 OD (3 eyes) and 1.1 OS (4 eyes).
Conclusions: :
Wavescan LASIK with flaps cut with the Intralase femtosecond laser results in normal levels of backscattered light at two months.
Keywords: refractive surgery: LASIK • refractive surgery: optical quality • optical properties