Abstract
Purpose
To characterize which clinical features are associated with the occurrence of atypical birefringence patterns (ABP) occasionally seen with scanning laser polarimetry (SLP).
Methods
Sixty-one subjects, including glaucoma patients, glaucoma suspects, and normal subjects, underwent a full clinical examination, standard visual field (VF) test, and a GDx-VCC SLP examination. One eye was selected from each patient. The magnitude of ABP was determined in two independent ways: using a support vector machine analysis (typical scan score (TSS)) and by a masked experienced observer. We assessed whether the magnitude of ABP was correlated with age, gender, the refractive state of the eye, corneal polarization axis and magnitude, GDx global parameters (TSNIT and NFI), and the VF status, as evident from glaucoma hemifield test (GHT), mean deviation (MD), and the pattern standard deviation (PSD).
Results
Of the 61 study eyes, 27 (44%) showed an ABP, based on a TSS cutoff (<82.5). A very high correlation was found between the TSS score and the masked experienced observer score (r2=0.80; P<0.001). The following clinical parameters were found, on bivariate analysis, to be significantly correlated with the presence of an ABP: age (r2=0.086; P=0.02); corneal polarization magnitude (r2=0.069; P=0.04); TSNIT (r2=0.16; P<0.001).
Conclusion
The presence and magnitude of ABP did not seem to be closely correlated with most clinical parameters. A low, but statistically significant, correlation was found for age and corneal polarization magnitude (r2=0.086 and 0.069, respectively). A low–medium correlation was found for TSNIT (r2=0.16); however, we speculate that this might represent a confounding effect, rather than an underlying association. We conclude that none of the clinical parameters investigated in this study appears to be strongly correlated with the presence of an ABP on SLP scans performed using the commercially available GDx-VCC.
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References
Zangwill LM, Bowd C . Retinal nerve fiber layer analysis in the diagnosis of glaucoma. Curr Opin Ophthalmol 2006; 17: 120–131.
Reus NJ, Lemij HG . Relationships between standard automated perimetry, HRT confocal scanning laser ophthalmoscopy, and GDx VCC scanning laser polarimetry. Invest Ophthalmol Vis Sci 2005; 46: 4182–4188.
Weinreb RN, Dreher AW, Coleman A, Quigley H, Shaw B, Reiter K . Histopathologic validation of Fourier-ellipsometry measurements of retinal nerve fiber layer thickness. Arch Ophthalmol 1990; 108: 557–560.
Zhou Q, Weinreb RN . Individualized compensation of anterior segment birefringence during scanning laser polarimetry. Invest Ophthalmol Vis Sci 2002; 43: 2221–2228.
Choplin NT, Zhou Q, Knighton RW . Effect of individualized compensation for anterior segment birefringence on retinal nerve fiber layer assessments as determined by scanning laser polarimetry. Ophthalmology 2003; 110: 719–725.
Greenfield DS, Knighton RW, Huang XR . Effect of corneal polarization axis on assessment of retinal nerve fiber layer thickness by scanning laser polarimetry. Am J Ophthalmol 2000; 129: 715–722.
Weinreb RN, Bowd C, Greenfield DS, Zangwill LM . Measurement of the magnitude and axis of corneal polarization with scanning laser polarimetry. Arch Ophthalmol 2002; 120: 901–906.
Tannenbaum DP, Hoffman D, Lemij HG, Garway-Heath DF, Greenfield DS, Caprioli J . Variable corneal compensation improves discrimination between normal and glaucomatous eyes with the scanning laser polarimeter. Ophthalmology 2004; 111: 259–264.
Lleo-Perez A, Ortuno-Soto A, Rahhal MS, Martinez-Soriano F, Sanchis-Gimeno JA . Intraobserver reproducibility of retinal nerve fiber layer measurements using scanning laser polarimetry and optical coherence tomography in normal and ocular hypertensive subjects. Eur J Ophthalmol 2004; 14: 523–530.
Blumenthal EZ, Frenkel S . Inter-device reproducibility of the scanning laser polarimeter with variable cornea compensation. Eye 2005; 19: 308–311.
Frenkel S, Slonim E, Horani A, Molcho M, Barzel I, Blumenthal EZ . Operator learning effect and interoperator reproducibility of the scanning laser polarimeter with variable corneal compensation. Ophthalmology 2005; 112: 257–261.
Bagga H, Greenfield DS, Feuer WJ . Quantitative assessment of atypical birefringence images using scanning laser polarimetry with variable corneal compensation. Am J Ophthalmol 2005; 139: 437–446.
Da Pozzo S, Marchesan R, Canziani T, Vattovani O, Ravalico G . Atypical pattern of retardation on GDx-VCC and its effect on retinal nerve fibre layer evaluation in glaucomatous eyes. Eye 2006; 20: 769–775.
Altman DG, Royston P . The cost of dichotomising continuous variables. BMJ 2006; 332: 1080.
Acknowledgements
EZB has received research support from Laser Diagnostic Technologies Incorporated.
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Orlev, A., Horani, A., Rapson, Y. et al. Clinical characteristics of eyes demonstrating atypical patterns in scanning laser polarimetry. Eye 22, 1378–1383 (2008). https://doi.org/10.1038/sj.eye.6702897
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DOI: https://doi.org/10.1038/sj.eye.6702897
