Development and validation of protocols for photographed food record by visually impaired people

To develop and validate protocols for photographed food record directed to visually impaired people.

Photographic techniques were established for capturing food images using a smartphone, and written protocols were defined. Thereafter, visually impaired people made photographic records of three standardised meals (breakfast, lunch/dinner, and snack) following the previously developed protocols. These photographs were then evaluated by a panel of experts (nutritionists and photographer) to indicate whether the framing, focus and angle were suitable to identify the food type, food amount and portion size. Agreement between the experts was assessed using Fleiss' Kappa.

Natal, the capital of Rio Grande do Norte, Brazil.

Visually impaired people (n 40); nutritionists (n 2); professional photographer (n 1).

Both protocols obtained a high proportion of satisfactory photos for all the items in the three dimensions investigated. When overall quality was assessed, the experts' agreement was a substantial that through the images it would be possible to identify the food type and portion size, both for Frontal Photos (k = 0·70 and k = 0·62, respectively) and Aerial Photos (k = 0·68 and k = 0·70, respectively). The degree of agreement that the photos presented a satisfactory global quality was moderate for the Frontal Photo (k = 0·43) and substantial for the Aerial Photo (k = 0·64). Participants who frequently used smartphone-type cell phones obtained better quality images for all these attributes for both protocols.

The protocols for photographed food record developed for visually impaired people in this study are feasible and present themselves as an alternative strategy to qualitatively assess their dietary intake.