Posters

Comparison of the Pulfrich phenomenon in presbyopic patients with a small-aperture inlay or a small-aperture contact lens

Poster Details

First Author: C. Van de Pol UNITED STATES

Co Author(s):                        

Abstract Details

Purpose:

To assess the perceptual impact of the inter-ocular difference in illuminance on perceived depth of moving objects, also known as the Pulfrich effect.

Setting:

UC Berkeley, CA

Methods:

Perceived depth of a moving target was measured in six KAMRA inlay subjects and six subjects with a customized small-aperture contact lens designed to mimic the inlay. All patients binocularly viewed a red disc that moved up to 11 degrees sinusoidally at a speed of 10 deg/sec in the horizontal direction. Patients reported the direction of the disc when it appeared to be in front of the display plane. Neutral density (ND) filter was introduced in the untreated eye to neutralize the Pulfrich effect. Filter strength for which no Pulfrich effect was seen was noted as the “nulling” density.

Results:

The Pulfrich effect was observed in nearly all of the contact lens subjects, however it was observed minimally in the KAMRA inlay subjects. The neutralizing ND filter value was not significantly different from zero for the KAMRA patients. The contact lens group was significantly more likely to see the Pulfrich effect than the KAMRA group (p=0.0007).

Conclusions:

Patients with the KAMRA inlay appear not to perceive significant Pulfrich effect, in comparison with subjects testing using a mimicking inlay. This evidence is consistent with the possibility of luminance adaptation in long-term inlay wearers.

Financial Disclosure:

One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented