The aim of the present study was to consider the hazardous effects of exposure to high concentrations of O2 (hyperoxia) on retinal protein and evaluate the protective role of low level laser therapy. Fifty Wistar albino rats were divided into three groups as follows: (a) control group (n=10 rats) without neither hyperoxia exposure nor laser treatment, (b) hyperoxia group (n=20 rats) received daily high concentration of O2 (90%), for one week (n=10 rats) and two weeks (n=10 rats) (c) hyperoxia group (n=20 rats) as the previous group was treated with a 670 nm light emitted diode laser two sessions aweek. experimental animals were sacrificed after one week and two weeks (n= 10 eyes rats each), Fourier transform infrared spectrum analysis was applied.
The results confirmed that retinal protein analysis revealed structurel deformation that appeared after hyperoxia in NH–OH and fingerprint regions. strO–Hsym band shifted from 3265±1 cm-1 to 3284±1 cm-1 (p < 0.01) and O-Hstr band width was increased from 118±1 to 150±2 (p < 0.01). CH3 deformation and COOassy bands are mostly affected in fingerprint region. Wavenumber of the first one was moved from 1294 ±2 cm-1 to 1327±1cm-1 (p < 0.01) where the second band was missed. After treatment with LED laser, amide  frequency may be enhanced in one week and two weeks with hyperoxia groups. Bands of amide , COOsym, CH3 Deformation and PO2 asymmetric have non-significant change in their frequencies (p˃0.05), Using low level laser therapy showed a clear improvement in retinal protein structure which illustrated by Fourier transform infrared analysis.