Available Technologies

Browse Penn-owned technologies available for licensing.

Anti-Pulfrich monovision ophthalmic corrections that reduce depth misperception

Technology Overview: 

Presbyopia is the age-related loss of your eyes’ ability to focus on objects that are up close. A normal part of the aging process, the effects of presbyopia typically begin in humans sometime around 45 years of age.

Researchers have estimated that there are close to 2 billion worldwide that have presbyopia.

Monovision is a common prescription lens correction for presbyopia. With monovision, each eye is corrected to focus light from a different distance, causing one image to be blurrier than the other. The brain suppresses the blurrier image and preferentially processes the sharper one, thereby expanding the depth of field. This differential blur that occurs between the lenses results in a motion illusion that makes people misperceive the distance and directional movement of three-dimensional objects. This depth misperception has been coined as the reverse Pulfrich effect.

By tinting the lens that causes the blurry image, the depth misperceptions will be eliminated. This non-invasive technique has been shown by measuring how blur differences affect neural processing times with sub-millisecond precision.

Currently, the biggest challenge with monovision corrections comes from the decrease in stereovision and depth misperceptions. The ability to eliminate depth misperceptions enables a new branch of “premium monovision corrections” that will have a positive impact in the prescription of this type of corrections.


Eliminates depth misperceptions currently experienced by users of monovision corrected lenses


  • Premium monovision ophthalmic correction lenses
  • Screening device to assess the reverse Pulfrich effect caused by interocular blur differences

Classic and Reverse Pulfrich Effects

Stage of Development: 

  • Corrected monovision misperceptions have been validated with 3 human observers in visual perception and visual optics
  • Prototype apparatus and software have been developed

Intellectual Property: 

Anti-Pulfrich monovision ophthalmic correction. U.S. Provisional Application No. 62/799,468.

Reference Media: 

Patent Information:


Docket # 19-8887

For Information, Contact:

Qishui Chen Licensing Officer, SEAS/SAS Licensing Group
University of Pennsylvania