In the submitted paper the authors pay attention to infrared radiation close to visible light is intensly absorbed by haemoglobin, melanin and xantophyll where- by part of the radiation energy is transformed into heat. The authors present three series of experiments where they investigated by different methods changes in the vitreous body after exposure to light, infrared radiation or raised temperature. Theys assume that on the defocused eye with a myopic conus which developed as a result of an inborn inadequate closure of the optic cup the light can cause a rise of temperature in the vitreous body. This leads to metabolic changes characterized by increased activity of lyzosomal enzymes causing loss of the spatial structure of hyaluronic acid and collagen biomolecules. Penetration of the altered vitreous fluid trought the conus can lead to degradation of the interstitial substances of the sclera. Suitable absorption glasses filtering infrared light close to visible light could reduce the hyperthermia of the vitreous body.

        Key words: myopia, UV radiation, IR radiation, heat, vitreous body