Can infrared rays be harmful to the eyes before being visible?

Most assuredly. In some cases, at power levels even lower than what would damage your eyes with visible light. You have a blink reflex that makes you shut your eyes to bright light. read more

Prolonged exposure to high levels of infrared radiation could lead to burns and cause eyeproblems, including cornea and retina damage, cataracts and injuries to the eye lens. In addition,infrared radiation can cause pain to the skin of a person in close contact with it. read more

Actual measured data used to prepare the ANSI Z136.1 -1993 standard indicate that eye damage thresholds are slightly lower for red than for infrared. Actual measured threshold levels for causing visible lesions in retinas. read more