Jinfeng Qu, Li Ma, Yardana Kaufman, and Ilyas Washington (Submitted, 2010).Purpose: To determine whether the porphyrin chlorin e6 can safely enhance the electrical response of the rabbit eye to light.

Methods: Electroretinogram (ERG) a- and b-wave amplitudes in response to green, blue, amber, red and deep red test flashes were compared for rabbits before and after administration of chlorin e6. Light and chlorin e6 induced retinal pigment epithelium (RPE) cell toxicity was measured by the firefly luciferase assay in cell cultures. 

Results: After administration of chlorin e6 ERG amplitudes were enhanced, particularly in response to red light. For deep red light, we measured up to a three-fold enhancement in b-wave amplitude. Chlorin and light showed negligible toxicity to RPE cells in culture at concentrations studied.

Conclusions: Chlorin e6 may safely be used to enhance the electrical response of the rabbit eye to light. Given the clinical use of chlorin e6, further studies aimed at answering whether porphyrins can enhance vision in humans are warranted.

Qu J, Kaufman Y, Washington I.            Invest Ophthalmol Vis Sci. 2009 Apr;50(4):1814-8.   To determine the concentration of coenzyme Q10 (CoQ10) in the human retina. METHODS: Eye tissues were lyophilized and exhaustively extracted with heptane. The extracts were analyzed for CoQ10 by high-performance liquid chromatography (HPLC). RESULTS: The average concentration of CoQ10 in the retina was 42+/-11 nanomoles/g dry retina for donors younger than 30 years of age and 24+/-13 nanomoles/g dry retina for donors older than 80 years of age. The average concentrations of CoQ10 in the choroid was 27+/-16 nanomoles/g dry choroid for donors younger than 30 age and 18+/-11 nanomoles/g dry choroid for donors older than 80. CONCLUSIONS: CoQ10 levels in the retina can decline by approximately 40% with age. This decline may have two consequences: a decrease in antioxidant ability and a decrease in the rate of ATP synthesis in the retina and, as such, this decline may be linked to the progression of macular degeneration. 

Washington, Iyas; Zhou, Jilin; Jockusch, Steffen; Turro, Nicholas J.; Nakanishi, Koji; Sparrow Janet R.  Photochemical and Photobiological Sciences, 2007, 6, 775.

Lebedeva, Irina V.; Washington, Ilyas; Sarkar, Devanand; Clark, Jennifer A.; Fine, Robert L.; Dent, Paul; Curiel, David T., Turro, Nicholas J.; Fisher Paul B.  Proc. Natl. Acad. Sci. U. S. A., 2007, 104 (9) 3484-3489.  

Isayama, Tomoki; Alexeev, Dmitriy; Clint, Makino; Washington, Ilyas; Koji Nakanishi; Turro, Nicholas J.  Nature, 2006, 443, 649.

Washington, Ilyas; Turro, Nicholas J.; Nakanishi, Koji Photchemistry and Photobiology, 2006, 82(6), 1394–1397.

Washington, Ilyas; Jockusch, Steffen; Itagaki, Yasuhiro; Turro, Nicholas J.; Nakanishi, Koji  Angew. Chem. Int. Ed. 2005, 117(43), 7259-7262.

Poon, Thomas; Sivaguru, J.; Franz, Roberto; Jockusch, Steffen; Martinez, Claudia; Washington, Ilyas; Adam, Waldemar; Inoue, Yoshihisa; Turro, Nicholas J.   J. Am. Chem. Soc. 2004, 126(34), 10498-10499.