FACTORS AFFECTING IMAGE ACQUISITION DURING SCANNING LASER POLARIMETRY

BACKGROUND AND OBJECTIVE: To illustrate artifacts that may be encounte red during measurement of the peripapillary retinal nerve fiber layer (RNFL) using scanning laser polarimetry (SLP). PATIENTS AND METHODS: A total of 426 patients with a variety of ocular diagnoses underwent RN FL measurements using SLP from June 1996 to April 1997. Scanning was p erformed by two operators whose reproducibility of measurements had be en previously validated. Images were selected to illustrate clinical f eatures that adversely affected measurement of the thickness of the RN FL. RESULTS: Image acquisition was difficult in eyes with corneal graf ts or edema, keratic precipitates, anterior uveitis, posterior subcaps ular cataract, vitreous opacity, peripapillary atrophy, posterior stap hyloma, and high axial myopia. These scans resulted in poor clinical c orrelation with visual field tests and optic nerve examination, poor r eproducibility of images, and unreadable images. CONCLUSION: 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.