Ascorbic acid concentration is reduced in the secondary aqueous humour of glaucomatous patients.
BACKGROUND
We aimed to evaluate the ascorbic acid concentration in secondary aqueous humour (AH) from glaucomatous patients and to compare it with primary AH from primary open-angle glaucoma patients and non-glaucomatous patients.


METHODS
Primary AH samples were prospectively obtained from clinically uncontrolled primary open-angle glaucoma patients and senile cataract patients (controls) prior to trabeculectomy and cataract surgery. Secondary AH samples were obtained from eyes with previous intraocular surgery, prior to trabeculectomy or cataract surgery. AH (0.1 mL) was aspirated by inserting a 26-gauge needle into the anterior chamber just before surgery and then immediately stored at -80 degrees C. The ascorbic acid concentration was determined in a masked fashion by high-pressure liquid chromatography.


RESULTS
A total of 18 patients with senile cataract, 16 glaucomatous patients with primary AH (no previous intraocular surgery) and 11 glaucomatous patients with secondary AH (previous intraocular surgery) were included. There was no difference in mean age between groups (P = 0.15). The mean +/- standard deviation concentration of ascorbic acid in the secondary AH from glaucomatous patients (504 +/- 213 micromol/L [95% confidence interval {CI}, 383-624]) was significantly lower than the concentration of ascorbic acid found in the primary aqueous of primary open-angle glaucoma (919 +/- 427 micromol/L [95% CI, 709-1128]) and control patients (1049 +/- 433 micromol/L [95% CI, 848-1249]; P < 0.01, Kruskal-Wallis test).


CONCLUSIONS
The ascorbic acid concentration in secondary AH of glaucomatous patients was approximately twofold lower in comparison with primary AH of glaucomatous and cataract patients. The implications of a reduced concentration of ascorbic acid in the secondary AH deserve further investigation.
Leite
Mauro T
MT
Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil.
Prata
Tiago S
TS
Kera
Clarissa Z
CZ
Miranda
Denise V
DV
de Moraes Barros
Silvia B
SB
Melo
Luiz As
LA
D000368:Aged; D001082:Aqueous Humor / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism*; D002387:Cataract Extraction; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005902:Glaucoma, Open-Angle / Q000378:metabolism* / Q000601:surgery; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D011446:Prospective Studies; D014130:Trabeculectomy
D001205:Ascorbic Acid