Calculation of solar ultraviolet influx in the eye using sunglasses

• Grant number: 21/12240-2
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2022
• End date: April 30, 2024
• Field of knowledge: Engineering - Biomedical Engineering
• Principal Investigator: Liliane Ventura Schiabel
• Grantee: Liliane Ventura Schiabel
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated researchers: Mauro Masili

Abstract

Ultraviolet (UV) protection for sunglasses is present in the media and discussed in the specialized literature. One of the aspects discussed in the literature says that the use of sunglasses is critical, under the argument that they can have the opposite effect if the lenses do not provide adequate UV protection. It reasons that sunglasses without proper UV protection fail to protect the eye. The main and natural mechanism is that, under exposure to the sun, the pupil contracts to reduce the incidence of radiation and protect the interior of the eye that, when not wearing sunglasses. Sunglasses, by mimicking the functions of the pupil in controlling light, inhibit its natural actions, resulting in a decrease in its contraction. Therefore, if dark lenses do not have adequate UV protection, there is an increase in the incidence of this radiation in the internal ocular environment, potentiating adverse effects. It affects more severely the ocular tissues, which are now unprotected by less contracted pupils, than in the cases in which no protection is used. However, specialized literature fails to adequately quantify and support this argument. This argument may be misleading by ignoring not only UV absorption by the materials that sunglasses lenses are made of, but also by ignoring absorption by the anterior structures of the eye, i.e., the cornea and aqueous humor. Thus, this work aims to do the calculation of the solar UV influx through the pupil of the human eye for two situations: when an individual wears sunglasses and do not wear them. In both situations, pupillary dilation will be taken into account in order to determine the area illuminated by solar UV radiation. So, we will first calculate the luminance (apparent brightness) of the daytime sky, through a modeling of solar radiation. Consequently, it is possible to estimate the pupil diameter, with and without sunglasses. Finally, the influx of UV radiation through the pupil in both situations is calculated. In this way, a ratio between the calculated inflows can be obtained, thus determining whether sunglasses with poor quality lenses would actually increase the influx of UV through the dilated pupil compared to the non-dilated pupil. For greater fidelity and realism, the respective UV absorptions by the ocular media before the pupil, the cornea and aqueous humor, will be taken into account. The field of view will also be considered as a function of brightness in both situations (with and without sunglasses). (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

MASILI, MAURO; VENTURA, LILIANE; IEEE. Sunglasses: calculation for corneal exposure and influx of UV through the pupil. 2023 IEEE 7TH PORTUGUESE MEETING ON BIOENGINEERING, ENBENG, v. N/A, p. 4-pg., 2023-01-01. (21/12240-2)

GUEDES, PEDRO; DE ANDRADE, AUGUSTO PEREZ; DA SILVA, PEDRO T. X.; VENTURA, LILIANE; IEEE. Sunglasses frame impact in eyes protection. 2023 IEEE 7TH PORTUGUESE MEETING ON BIOENGINEERING, ENBENG, v. N/A, p. 4-pg., 2023-01-01. (21/12240-2)