Factors Affecting Image Acquisition During Scanning Laser Polarimetry

Abstract

To illustrate artifacts that may be encountered during measurement of the peripapillary retinal nerve fiber layer (RNFL) using scanning laser polarimetry (SLP). A total of 426 patients with a variety of ocular diagnoses underwent RNFL measurements using SLP from June 1996 to April 1997. Scanning was performed by two operators whose reproducibility of measurements had been previously validated. Images were selected to illustrate clinical features that adversely affected measurement of the thickness of the RNFL. Image acquisition was difficult in eyes with corneal grafts or edema, keratic precipitates, anterior uveitis, posterior subcapsular cataract, vitreous opacity, peripapillary atrophy, posterior staphyloma, and high axial myopia. These scans resulted in poor clinical correlation with visual field tests and optic nerve examination, poor reproducibility of images, and unreadable images. Anterior and posterior segment pathologies, particularly those localized to the cornea and lens, may produce spurious RNFL measurements and should be carefully considered prior to clinical decision making.