Optometrists weigh in on #TheDress

On Thursday, a photo of a dress was posted to the blogging site Tumblr and went viral.

In the original post, the author said that she and her friends were debating over the color of the dress – some of them saw it as blue and black and some of them saw it as white and gold.

In a later post, the author said that she had seen the dress in person and that it was blue and black.

While the debate continues to rage on social media, Primary Care Optometry News spoke to three PCON contributors about why people are seeing the dress differently.

Gary L. Morgan, OD, who writes a PCON blog on blue light, told PCON: "In looking at the various articles written, experts in neuro seem to think it is perceptual rather than anatomical. I see it as pale blue and gold. Interestingly, with blue filtering lenses on, I cannot see any change in color, as BluTech lenses (Eye Solutions) containing ocular lens pigment do not change color perception.

"Macular pigment is our internal blue light filter, filtering light pre-receptorally, which studies show has an impact on our contrast sensitivity,” he continued. “Perhaps macular pigment optical density is having some impact on the way people perceive this? It would be interesting to know if people with low macular pigment perceive the colors of the dress differently than those with normal or high levels of macular pigment; however, macular pigment may also have nothing to do with this."

PCON Editorial Board member John A. McCall Jr., OD, also weighed in.

“There are two types of photoreceptors in the retina: rods and cones,” he began. “The rods contain rhodopsin and are sensitive to blue and green light. Cones contain opsins as their primary visual pigments and, depending on their structure, they are sensitive to long (red), medium (green) or short (blue) wavelengths of light. Cones of different wavelength sensitivity are the basis of visual perception.”

He added that cones do not simply detect light; they also adapt to environmental light.

McCall explained to PCON that color blindness occurs when some cone photoreceptors are missing or not functioning at all, and color anomaly is when all cones are present, but not functioning properly.

“So, you don’t have to be color blind to have some of the receptors receive information better than others,” he said.

The eye’s lens also affects how people perceive color, McCall continued.

“As we age, the lens begins to form cataracts, and the melanin formation in the lens blocks blue light,” he said. “Logically, someone who is 60, with early cataracts, would perceive colors differently than someone who’s 20 and has a clear lens.”

Regarding the dress, McCall said it is obviously a mixture of primary colors.

“If it were made up of just primary colors, there would be no controversy,” he said.

“My theory regarding people perceiving the dress as different colors is twofold,” McCall said. “One: Not all cones are created equal in every person. How you perceive a mixture of primary colors depends on which cones are functioning the best. Two: Your perception of blue light diminishes with age, as melanin is being formed in the lens, so an older person will perceive blue differently than a younger person.”

He added: “Personally, I see the dress as blue and brown.”

Jerome A. Legerton, OD, MS, MBA, FAAO, also a PCON Editorial Board member, added his perspective.

“It is one thing for two people to see different colors on their individual screens and another to see different colors when looking at the same screen, in the same location, with the same ambient lighting and at the same time,” he said.

The brightness on someone’s screen will change the color that person sees, he said.
“Just like the Photoshop work can change how something appears by changing the brightness or the balance, you can change the appearance of the colors for yourself by changing just the brightness of your display,” Legerton said.

“Go to the display settings while having the image of the dress on your screen and raise and lower the brightness,” he continued. “You are not changing color balance at all. You are just changing the brightness. You will see that the dress looks more gold and white when the brightness is high and it looks more blue and black when the brightness is low. The ratio of the red, green and blue does not change, only the power delivered to each and all.”

In low light you can have low brightness, and it will appear blue/black, Legerton said. In high ambient light you must have high brightness, and it will appear white and gold.

“It is more difficult to see the dress when you lower the brightness in high ambient light, but it still shifts to blue/black,” he noted.

Legerton said that the energy level of the wavelengths is another factor that comes into play.

Energy is inversely proportional to wavelength, he said. Blue is a shorter wavelength and higher energy.

“The difference in the energy of the colors of the spectrum shifts the apparent color when the brightness drops, since the high energy of blue prevails over the relatively lower energy of red when all wavelengths are reduced in brightness,” Legerton said.

“Yet another factor is Purkinje shift, in which the sensitivity of the eye shifts toward the blue end of the spectrum as the illumination level drops,” he added. “The peak sensitivity of the retina is more yellow-orange in photopic lighting, while it shifts toward blue-green in scotopic lighting.

“If one combines the impact of the energy difference in the spectrum when brightness reduces with the Purkinje shift in retinal sensitivity,” he continued, “it would not be surprising to be able to see a change in color appearance with changes in ambient light levels and/or the inherent brightness of a digital image.”

Legerton noted: “None of this would explain two people standing side by side in the same light and looking at the same picture and labeling the colors differently, however.”

This viewing situation would involve “the role of pupil size; distribution of red (long), green (medium) and blue (short) cone photoreceptors, the difference of the short cone receptors compared to the medium and long with regard to signal transduction by way of horizontal bipolar cells in an on-only vs. on-off signaling; the role of rods responding to color (causing the Purkinje shift); and, finally, the Stiles Crawford effect and the impact of pupil size on the angle of incidence of the colored light on the cone photoreceptors.” – by Chelsea Frajerman and Nancy Hemphill, ELS, FAAO

Disclosures: McCall has no relevant financial disclosures. Morgan is an advisory board member for Arctic Dx, MacuHealth and Signet Armorlite. Legerton serves as a consultant to the ophthalmic industry through his company, Global Ophthalmic Consultants LLC.