Researchers from the University of Cambridge and Meta Reality Labs have studied the resolution limit of the human eye, questioning whether ultra-high-definition televisions such as 4K or 8K screens offer a noticeable improvement for viewers.
The study measured participants’ ability to detect details in color and greyscale images on screens at varying distances and angles. The researchers found that, under typical conditions in an average-size UK living room with about 2.5 meters between the viewer and a 44-inch TV, there is no significant advantage to choosing a 4K or 8K television over a lower resolution Quad HD (QHD) model of the same size.
The research team developed an online calculator that allows users to input their room size, screen dimensions, and resolution to determine the most suitable display for their home. Their findings are published in Nature Communications.
Dr Maliha Ashraf from Cambridge’s Department of Computer Science and Technology explained: “As large engineering efforts go towards improving the resolution of mobile, AR and VR displays, it’s important to know the maximum resolution at which further improvements bring no noticeable benefit. But there have been no studies that actually measure what it is that the human eye can see, and what the limitations of its perception are.”
Professor Rafał Mantiuk, also from Cambridge’s Department of Computer Science and Technology, added: “If you have more pixels in your display, it's less efficient, it costs more and it requires more processing power to drive it. So we wanted to know the point at which it makes no sense to further improve the resolution of the display.”
Instead of focusing on specific screen specifications, researchers measured pixels per degree (PPD), which refers to how many individual pixels fit into a one-degree slice of vision. This method answers how a screen appears from where someone is sitting rather than just stating its technical capabilities.
Ashraf noted: “This measurement has been widely accepted, but no one had actually sat down and measured it for modern displays, rather than a wall chart of letters that was first developed in the 19th century.”
The study found that for greyscale images viewed directly ahead, people could resolve detail up to an average of 94 PPD. For red and green patterns this dropped slightly to 89 PPD; for yellow and violet patterns it was significantly lower at 53 PPD.
Mantiuk commented: “Our brain doesn’t actually have the capacity to sense details in colour very well, which is why we saw a big drop-off for colour images, especially when viewed in peripheral vision. Our eyes are essentially sensors that aren’t all that great, but our brain processes that data into what it thinks we should be seeing.”
The results were modeled across population variations so manufacturers can design displays meeting retinal resolution standards for most people instead of just an average observer.
Dr Alex Chapiro from Meta Reality Labs said: “Our results set the north star for display development, with implications for future imaging, rendering and video coding technologies.”
The full reference for this research is Maliha Ashraf, Alexandre Chapiro, Rafał K. Mantiuk. ‘Resolution limit of the eye: how many pixels can we see?’ Nature Communications (2025). DOI: 10.1038/s41467-025-64679-2