Korean J Ophthalmol.  2008 Mar;22(1):18-25. 10.3341/kjo.2008.22.1.18.

Relationship between Scanning Laser Polarimetry with Enhanced Corneal Compensation and with Variable Corneal Compensation

• Kim KH
• Choi J
• Lee CH
• Cho BJ
• Kook MS

• KMID: 1107486
• DOI: http://doi.org/10.3341/kjo.2008.22.1.18

Abstract

PURPOSE: To evaluate the structure-function relationships between retinal sensitivity measured by Humphrey visual field analyzer (HVFA) and the retinal nerve fiber layer (RNFL) thickness measured by scanning laser polarimetry (SLP) with variable corneal compensation (VCC) and enhanced corneal compensation (ECC) in glaucomatous and healthy eyes. METHODS: Fifty-three eyes with an atypical birefringence pattern (ABP) based on SLP-VCC (28 glaucomatous eyes and 25 normal healthy eyes) were enrolled in this cross-sectional study. RNFL thickness was measured by both VCC and ECC techniques, and the visual field was examined by HVFA with 24-2 full-threshold program. The relationships between RNFL measurements in superior and inferior sectors and corresponding retinal mean sensitivity were sought globally and regionally with linear regression analysis in each group. Coefficients of the determination were calculated and compared between VCC and ECC techniques. RESULTS: In eyes with ABP, R2 values for the association between SLP parameters and retinal sensitivity were 0.06-0.16 with VCC, whereas they were 0.21-0.48 with ECC. The association of RNFL thickness with retinal sensitivity was significantly better with ECC than with VCC in 5 out of 8 regression models between SLP parameters and HVF parameters (P<0.05). CONCLUSIONS: The strength of the structure-function association was higher with ECC than with VCC in eyes with ABP, which suggests that the ECC algorithm is a better approach for evaluating the structure-function relationship in eyes with ABP.

Keyword

GDx-ECC; GDx-VCC; Scanning laser polarimetry; Structure-function relationship

MeSH Terms

Algorithms
Birefringence
Cornea/physiology
Cross-Sectional Studies
*Diagnostic Techniques, Ophthalmological
Female
Glaucoma/*diagnosis
Humans
Intraocular Pressure
Lasers/diagnostic use
Male
Middle Aged
Nerve Fibers/*pathology
Optic Nerve Diseases/*diagnosis
Prospective Studies
Retinal Ganglion Cells/*pathology
Vision Disorders/*diagnosis
*Visual Fields

Figure

• 

  Fig. 1 Correspondence map of the GDx-VCC regional parameters (A) and the HVFA 24-2 paradigm (B) for a right eye. In the present study, peripapillary GDx-VCC measurements and visual field test points were grouped into two regional corresponding sectors of superior and inferior average on the GDx-VCC printouts, based on the article by Garway-Heath et al.21 Corresponding sectors were grayscaled and named after the parameters on the GDx-VCC printouts (Superior and inferior average) in relation to the optic disc.

• 

  Fig. 2 Scatterplots showing the associations between VCC and ECC parameters and corresponding retinal sensitivities expressed in dB by linear regression in eyes with ABP. (A) TSNIT SD with VCC and ECC versus global mean sensitivity (MS) expressed in dB. (B) Superior average with VCC and ECC versus inferior MS expressed in dB. (C) Inferior average with VCC and ECC versus superior MS expressed in dB. R2 values were significantly higher for linear associations of these SLP parameters with retinal sensitivity with ECC than with VCC (P-values: A, 0.001; B, 0.002; C, <0.001. Wilcoxon signed ranks test of the absolute prediction errors). Solid lines, linear fits; dashed lines, confidence intervals. R2 values are shown for each fit.

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