Korean J Ophthalmol.  2019 Apr;33(2):131-137. 10.3341/kjo.2018.0075.

Comparison of Blue and Green Confocal Scanning Laser Ophthalmoscope Imaging to Detect Retinal Nerve Fiber Layer Defects

• Joung JY
• Lee WJ
• Lee BR

• KMID: 2442617
• DOI: http://doi.org/10.3341/kjo.2018.0075

Abstract

PURPOSE
We detected retinal nerve fiber layer (RNFL) defects using a confocal scanning laser ophthalmoscopy (CSLO) with both blue and green laser sources and evaluated image quality based on laser wavelength.
METHODS
This was a retrospective observational case study. Blue and green CSLO images of 181 eyes with suspected glaucoma were evaluated and compared. Three independent observers identified the presence of RNFL defects and determined which CSLO imaging source provided superior visibility of the defect. After assessing the defect imaging by laser source, demographics and image quality indices of optical coherence tomography between blue better and green better groups were analyzed.
RESULTS
Both blue and green CSLO showed high discriminating ability for RNFL defects. The discriminating ability of blue CSLO was significantly greater than that of green CSLO (p = 0.004). Among eyes with a detectable RNFL defect, 61.8% were better visualized with the blue laser compared to the green laser. Compared with the blue better group, the green better group was significantly older (p = 0.009), had a greater proportion of females (p = 0.005), had poorer best-corrected visual acuity (p = 0.001), more severe cataracts (p = 0.001), lower signal strength (p = 0.003), and poor image quality indices (p = 0.001).
CONCLUSIONS
Both blue and green CSLO imaging was useful for detecting RNFL defects, but blue CSLO was superior to green CSLO in quality of RNFL defect imaging in most patients with clear media.

Keyword

Confocal scanning laser ophthalmoscope; Red-free imaging; Retinal nerve fiber layer defect

MeSH Terms

Cataract
Demography
Female
Glaucoma
Humans
Nerve Fibers*
Ophthalmoscopes*
Ophthalmoscopy
Retinaldehyde*
Retrospective Studies
Tomography, Optical Coherence
Visual Acuity
Retinaldehyde

Figure

• 

  Fig. 1 Comparison of receiver operating characteristic curves created using blue confocal scanning laser ophthalmoscope (CSLO) imaging and green CSLO imaging.

• 

  Fig. 2 Representative confocal scanning laser ophthalmoscope (CSLO) imaging of the blue better group. (A) Case 1: 82-year-old male. Multiple retinal nerve fiber layer (RNFL) defects (white arrow) were visible with both blue and green CSLO imaging. Visualization of RNFL defects was better with blue compared to green CSLO imaging. (B) Case 2: 63-year-old female. A superior temporal RNFL defect (white arrow) was visible with both blue and green CSLO imaging. Visualization of the RNFL defect was better with blue compared to green CSLO imaging.

• 

  Fig. 3 Representative confocal scanning laser ophthalmoscope (CSLO) imaging of the green better group. (A) Case 3: 73-year-old female. An inferior temporal retinal nerve fiber layer (RNFL) defect (white arrow) was visible with both blue and green CSLO imaging. This patient had corneal opacity. Visualization of the RNFL defect was better with green versus blue CSLO imaging. (B) Case 4: 76-year-old female. An inferior RNFL defect (white arrow) was visible with both blue and green CSLO imaging. The patient had severe cataracts according to slit lamp examination. Visualization of the RNFL defect was better with green versus blue CSLO imaging. In particular, the boundary of the RNFL defect and its relationship with adjacent retinal vasculature were more clearly visible with green CSLO imaging.

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