Impaired visual function in glaucoma

Research output: Contribution to journalArticle

Abstract

Objective: This work aims to evaluate whether glaucomatous visual field defects could be related to an impaired retinal function, to a delayed neural conduction in postretinal visual pathways, or both. Methods: Visual field by Humphrey perimeter (central 24-2 threshold test) and simultaneous recordings of visual evoked potential (VEP) and pattern electroretinogram (PERG) were assessed in 21 subjects with open angle glaucoma (POAG) and in 15 age-matched controls (C). Results: VEP: in POAG eyes we found P100 latency significantly (P <0.01) delayed when compared with controls and correlated with mean deviation (index of global visual field damage, MD) of 24-2 Humphrey perimetry (P <0.001); the P100 amplitudes were significantly (P <0.01) lower in POAG eyes than in control eyes and correlated with MD (P <0.001). PERG: POAG eyes showed P50 latency significantly (P <0.01) delayed when compared with controls and correlated with MD (P = 0.002); the P50 and N95 amplitudes were significantly (P <0.01) lower in POAG than in control eyes and correlated with MD (P50: P = 0.006; N95: P = 0.002). Retinocortical time (RCT: difference between VEP P100 and PERG P50 latencies) and latency window (LW: difference between VEP N75 and PERG P50 latencies) were significantly (P <0.01) longer in POAG eyes than in control eyes and correlated with MD (RCT: P <0.001; LW: P <0.001). No significant correlations (P > 0.05) were found between electrophysiological parameters and the corrected pattern standard deviation (index of localized visual field damage) of 24-2 Humphrey perimetry Conclusion: In patients with open angle glaucoma the reduction of the index of global visual field damage (MD) could be ascribed to two sources of functional impairment: one retinal (impaired PERG) and one postretinal (delayed RCT and LW). In the postretinal impairment, a postsynaptic degeneration at the level of the lateral geniculate nucleus could be suggested.

Original languageEnglish
Pages (from-to)351-358
Number of pages8
JournalClinical Neurophysiology
Volume112
Issue number2
DOIs
Publication statusPublished - 2001

Fingerprint

Visual Fields
Glaucoma
Visual Evoked Potentials
Open Angle Glaucoma
Geniculate Bodies
Visual Field Tests
Visual Pathways
Neural Conduction

Keywords

  • Glaucoma
  • Pattern electroretinogram
  • Static perimetry
  • Visual evoked potential
  • Visual pathway

ASJC Scopus subject areas

  • Clinical Neurology
  • Physiology (medical)
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems

Cite this

Impaired visual function in glaucoma. / Parisi, Vincenzo.

In: Clinical Neurophysiology, Vol. 112, No. 2, 2001, p. 351-358.

Research output: Contribution to journalArticle

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