espectrofotometria de lentes oftálmicas orgânicas de visão simples submetidas à radiação ultravioleta a, ultravioleta b e luz visível spectrophotometry of organic ophthalmic lenses of simple vision submitted to ultraviolet a and b radiation and visible light

OBJETIVO: Verificar, por meio de estudo espectrofotométrico, o poder de filtração da radiação ultravioleta A (UVA) e B (UVB) e transmitância da luz visível em lentes incolores de visão simples. MÉTODOS: Análise espectrofotométrica (espectrofotômetro modelo Humphrey Lens Analyzer LA 360) de 14 tipos de lentes oftálmicas incolores, confeccionadas em material orgânico de diferentes características. Cada tipo de lente foi representado por 20 exemplares, totalizando amostra de 280 lentes estudadas. Posteriormente procedeu-se a análise da curva de transmitância na faixa do espectro entre 290 e 700 nm. RESULTADOS: Em relação à radiação UVB, todas as lentes estudadas apresentaram transmitância de 0 a 1%. Tiveram melhor desempenho (0% de transmitância): Trivex, Rugged Fashion Wear, AO Lite, Hard Resin, Sola Light 1.56, MAR 1.56, MAR CR39, Stylis Crizal, Crizal, AirWear e Orma 15. Quanto à radiação UVA a transmitância oscilou de 1 a 18%. Tiveram melhor desempenho (transmitância de 1%): Miolight anti-reflexo 1.56, Trivex, Miolight Excellence, Rugged Fashion Wear, Sola Light, MAR 1.56, Stylis Crizal e Air Wear. Nenhuma das lentes estudadas filtrou completamente a radiação UVA. Todas as lentes estudadas apresentaram transmitância superior a 95% em relação ao espectro visível, havendo variação de 95 a 100%. CONCLUSÕES: Todas as lentes estudadas apresentaram poder de filtração UVB de 99 a 100%, UVA de 82 a 99% e 95 a 100% de transmitância da luz visível. A presença de tais filtros em lentes incolores amplia as possibilidades de prescrição deste recurso de proteção ocular.
PURPOSE: To verify, by spectrophotometric study, the filtration power of A and B ultraviolet radiation and transmittance of visible light in colorless lenses of simple vision. METHODS: Spectrophotometric analysis (Model Humphrey Lens Analyzer LA 360 spectrophotometer) of 14 types of colorless ophthalmic lenses, made of organic material of different characteristics. Each lens type was represented by 20 copies, totaling a sample of 280 studied lenses. Later, the analysis of the transmittance curve in the spectrum range of 290 to 700 nm was performed. RESULTS: In relation to UVB radiation, all of the studied lenses presented transmittance from 0 to 1%. The ones that had a better performance (0% transmittance) were: Trivex, Rugged Fashion Wear, AO Lite, Hard Resin, Sola Light 1.56, MAR 1.56, MAR CR39, Stylis Crizal, Crizal, Air Wear, Orma 15. As for UVA rays, the transmittance oscillated from 1 to 18%. The ones that had a better performance (1% transmittance) were: Miolight Anti Reflex 1.56, Trivex, Miolight Excellence, Rugged Fashion Wear, Sola Light, MAR 1.56, Stylis Crizal e Air Wear. None of studied lenses completely filtered UVA radiation. All of the studied lenses presented transmittance over 95% in relation to the visible spectrum, with a variation from 95 to 100%. CONCLUSIONS: The studied colorless lenses present a real capacity of filtration of UV radiation, especially regarding the UVB spectrum, which is favorable since this is the main portion of the spectrum related to ocular damages. All of the studied lenses presented UVB filtration power from 99 to 100%, UVA from 82 to 99% and 95 to 100% of transmittance of visible light. The presence of such filters in colorless lenses increases the possibilities of prescription of this resource of ocular protection.