The occurrence and features of the atypical birefringence pattern in scanning laser polarimetry using GD × VCC in healthy children and its impact on the retinal nerve fiber layer thickness values.
OBJECTIVE
To investigate the occurrence and features of the atypical birefringence pattern (ABP) images in scanning laser polarimetry with variable corneal compensation (GD×VCC) in healthy children and to assess their impact on the values of the retinal nerve fiber layer (RNFL) thickness.


METHODS
GD×VCC scans in 120 healthy white school-aged children with mean age ± standard deviation (SD) 12.85 ± 3.0 years were evaluated using typical scan score (TSS) calculation and by subjective grading of the scans. Statistical analysis including the impact of ABP on the RNFL thickness in GD × VCC Temporal-Superior-Nasal-Inferior-Temporal (TSNIT) parameters was done.


RESULTS
The ABP was found in 18 out of 120 patients (15%) at cut-off value of TSS <80. Subjective evaluation of the scans raised the frequency of ABP to 20% of patients. The mean ± SD values of TSNIT Average, Superior Average, and Inferior Average in 26 eyes with ABP versus 214 eyes with normal birefringence pattern were 66.99 ± 7.29 μm versus 58.00 ± 6.22 μm (P = 7.2E to -11), 78.43 ± 9.27 μm versus 72.33 ± 8.72 μm (P = 0.001) and 80.87 ± 12.01 μm versus 70.00 ± 10.20 μm (P = 0.000001), respectively. The same comparison in TSNIT SD showed minimal difference and was 25.42 ± 5.84 μm versus 26.41 ± 4.81 μm (P = 0.41).


CONCLUSIONS
The occurrence of ABP in children is not rare and may significantly distort the measured values of the RNFL thickness in TSNIT parameters using GD × VCC.
Filous
Ales
A
Department of Ophthalmology for Children and Adults, Charles University in Prague, 2nd Faculty of Medicine, Prague, Czech Republic. ales.filous@lfmotol.cuni.cz
Hlozánek
Martin
M
Hladíková
Marie
M
D016477:Artifacts; D001718:Birefringence; D002648:Child; D003315:Cornea / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009412:Nerve Fibers; D009898:Optic Disk / Q000033:anatomy & histology*; D012029:Refraction, Ocular / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000166:cytology*; D057109:Scanning Laser Polarimetry; D012737:Sex Factors; D014065:Tonometry, Ocular