Effect of Optical Defocus on the Kinetic Perimetry in Young Myopic Participants

Purpose: The prospective study evaluated the effects of optical defocus on kinetic sensitivity using automated kinetic perimetry. Materials and Methods: The 17 eyes of 17 healthy young participants were evaluated. All of the participants had myopia (>= -5.00 D) and mild to no astigmatism (51.00 D). Automated kinetic perimetry was performed using the Octopus 900 perimeter with Goldmann stimuli III4e, I4e, I3e, I2e, and I1e, with stimuli presented at 14 predetermined meridians, and a velocity of 3 degrees/s. Optical defocus was induced with soft contact lenses, and varied in 1 D increments between 0 and +7 D. Kinetic sensitivity at each defocus was evaluated and compared to sensitivity with no defocus. Results: Although kinetic sensitivity with the III4e and I4e stimuli decreased slightly at the inferior nasal, total kinetic sensitivity measured with the III4e and I4e stimuli was unaffected by optical defocus. Conversely, kinetic sensitivity measured with the I3e, I2e, and I1e stimuli decreased at defocus greater than +6 D (p<0.05), +3 D (p<0.01), and at a defocus greater than +1 D (p<0.01), respectively. Conclusions: Kinetic sensitivity was unaffected by defocus when measured with III4e and I4e stimuli. However, measurements with I3e, I2e, and I1e stimuli were affected, in particular measurements with I2e and I1e stimuli. Therefore, we conclude that optimal refractive correction with a contact lens or a spectacle lens is required in order to obtain accurate kinetic perimetry results, particularly for lower intensity stimuli.