Abstract
Abstract: :
Purpose: Exfoliation syndrome (XFS) is a disorder involving aberrant extracellular matrix production. The principal ocular cells involved in exfoliation material synthesis are closely associated with the aqueous humor. High ascorbate concentration in the aqueous humor has been known for decades. We have evaluated the levels of ascorbic acid in the aqueous humor of patients with XFS in comparison with normal age-matched control patients. Methods: Aqueous humour samples were obtained at the beginning of phacoemulsification cataract surgery. Eighty aqueous samples, 40 from cataract patients with XFS and 40 from age matched cataract patients without XFS have been analysed. Ascorbic acid concentration in the aqueous was determined by a microplate assay method. Protein concentration was also measured in the same samples. Results: The mean concentration of ascorbic acid in the aqueous humor from patients with XFS (0,86 ± 0,43 mM) was significantly lower than that measured in the aqueous humor of age matched control patients (1,15 ± 0,50 mM); P=0,0068). Total protein concentration was found to be significantly higher in the XFS group. No correlation could be established between ascorbic acid level and protein concentration. Furthermore, ascorbic acid concentration did not correlate with age. Conclusion: Accumulating evidence suggests that ascorbic acid in the aqueous plays a vital role in the antioxidant defense mechanism and protects ocular tissues (e.g. the lens) from ultraviolet radiation. A significantly lower mean level of ascorbic acid was documented in the aqueous humor of patients with XFS. This may imply a role for ascorbic acid in the pathobiology of XFS. Our finding may also provide for the first time a logical explanation for some, previously unexplained, features of XFS such as the reported link of its prevalence with ultraviolet irradiation and the higher incidence of cataract formation in XFS.
Keywords: 317 anterior chamber • 324 aqueous • 321 antioxidants