title: Elevated urine formaldehyde in elderly patients with primary open angle glaucoma.
abstract: OBJECTIVE
  To investigate the risk factor of primary open angle glaucoma (POAG), which is the leading cause of irreversible blindness worldwide. An abnormally high level of endogenous formaldehyde (FA) has recently been found correlated with cell death and neurodegenerative disease, raising the possibility of a putative correlation of abnormal endogenous FA with POAG.
  
  
  METHODS
  Thirty-four elderly patients with POAG and sixteen healthy controls were enrolled. Glaucomatous visual defects were present at both the functional (visual field) and structural [retinal nerve fiber layer (RNFL) thickness] levels. Morning urine samples were obtained and were analyzed by high-performance liquid chromatography (HPLC) to detect the endogenous FA level in a double blind manner.
  
  
  RESULTS
  Patients with POAG (P<0.05) had significantly higher urine FA levels. The urine FA level of patients with severe visual field defects [mean deviation (MD)≥12 dB] was significantly (P<0.001) greater than that of patients with mild to moderate defects (MD<12 dB). By optical coherence tomography (OCT), the superior and inferior RNFL thickness of POAG group was significantly (P<0.001) thinner than in controls. Furthermore, the superior and inferior thinning of the RNFL was correlated with the elevation of urine FA concentration.
  
  
  CONCLUSIONS
  Endogenous FA level is positively correlated with the neuronal defects of POAG.
authors.affiliation: Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China; Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100191, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cui
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Su
authors.affiliation: Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China; Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100191, China.
authors.forename: Shao-Dan
authors.initials: SD
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China; Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100191, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Ying-Ge
authors.initials: YG
authors.lastname: He
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Ophthalmology, Peking University Third Hospital, Beijing 100191, China; Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing 100191, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Einhorn Clinical Research Center, New York Eye and Ear Infirmary of Mount Sinai, New York, NY 10003, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Ritch
authors.affiliation: State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Rong-Qiao
authors.initials: RQ
authors.lastname: He
keywords: Alzheimer's disease; primary open angle glaucoma; urine formaldehyde