Assessing the vision of recently contacted indigenous populations requires instruments designed for the cultural reality of each people. This was the challenge faced by a team of researchers from Roraima, who developed an image-based visual acuity test specifically for the Yanomami people. The study was published by the journal Qualis A Open Minds , owned by CPAH, the Heráclito Research and Analysis Center, under the technical management of Editora Atena.
The research is authored by Heleno Almeida Lima , from Plazma Studios in Boa Vista, and by Maria Christina Chagas Ferreira , Marcos Antonio Pellegrini , and Bianca Jorge Sequeira , from the Federal University of Roraima.
Why the Snellen chart doesn’t work for everyone.
The most widely used vision test in the world, known as the Snellen chart, was created within a Western visual model, based on the recognition of the Roman alphabet and standardized typographic forms. The problem is that its performance depends on prior familiarity with these abstract symbols.
The Yanomami people are predominantly illiterate, organized into different linguistic subgroups, and distributed across vast regions of the Amazon rainforest. According to researchers, this population’s contact with Western writing is still recent, limited, and sporadic. Therefore, letters and typographical forms simply do not make sense to most of this population, which can lead to diagnostic errors that have nothing to do with the patient’s actual visual capacity.
From the forest to the paper: how the symbols were chosen.
To solve this problem, the team went through a research process that combined semiotics, ophthalmology, and anthropology. The first step was to identify elements visually familiar to the Yanomami universe, based on ethnographic descriptions compiled in the book The Fall of the Sky , by the shaman Davi Kopenawa in partnership with the anthropologist Bruce Albert.
Based on this survey, the researchers selected five symbols to compose the long-distance table:
● Turtle
● Cobra
● Toucan
● Tree
● Helicopter
Each image underwent a process of graphic simplification until it became a vector drawing with stable outlines, high contrast, and proportions calculated to function as an optotype, that is, the symbol used to measure visual acuity in ophthalmological tests.
Tested on 158 people in Boa Vista.
The instrument was evaluated between 2022 and 2024, during a study on eye health conducted at the Yanomami Indigenous Health Center, CASAI Y, in Boa Vista. In total, 158 people from the Yanomami ethnic group, from 5 years of age, participated in the research, with the mediation of bilingual interpreters, since most speak only the Yanomami language and do not have formal literacy.
The validation compared the performance of the new chart with the traditional inverted test known as Snellen’s E. According to the results, the two instruments showed functional equivalence in identifying visual acuity levels. The difference appeared in the test’s fluidity: the pictographic chart generated faster responses and required less prior instruction, indicating greater cognitive familiarity with the adapted symbols.
The helicopter that became the most recognizable symbol of all.
One of the most curious findings of the study concerns the helicopter symbol, called “buru buru” by the Yanomami, a sound reference to the rotor noise. Among all the designs tested, it was the one most quickly identified, by both adults and children.
The key detail is that, unlike the turtle, the toucan, or the tree, the helicopter is not an element originating from the forest. It is an object of interethnic contact, incorporated into the daily life of the Yanomami through health, supply, and communication activities in hard-to-reach territories. For the researchers, this result shows that the visual repertoire of a people in recent contact with Western culture is not static, but a living system that absorbs and reinterprets external elements without losing its internal coherence.
A model also designed for close-up viewing.
In addition to the distance vision chart, the team developed a version for assessing near vision, adapted from the Jaeger scale and organized for testing at a distance of 37 centimeters. The material uses the same set of symbols, resized, which ensures consistency between the two instruments.
All the material was developed for low-cost printing on A4 paper, easy transport and use in the field, including the possibility of being affixed to walls, doors or improvised structures during mobile services in remote areas.
A possible path for other indigenous peoples
The research was conducted in accordance with the ethical principles of the Declaration of Helsinki and approved by a research ethics committee, under a specific protocol. The authors acknowledge limitations, such as the impossibility of applying formal psychophysical protocols given the field conditions, which made observational validation necessary.
Nevertheless, preliminary results indicate that the Yanomami pictographic chart is a promising tool for clinical and epidemiological screenings in indigenous contexts, and could serve as a model for similar adaptations among other peoples in Brazil or abroad.
This text is for informational purposes only and is based on a scientific study focused on the development of visual screening instruments. It does not replace a complete ophthalmological evaluation, which should always be performed by a healthcare professional.
