J Korean Ophthalmol Soc.  2016 May;57(5):800-807. 10.3341/jkos.2016.57.5.800.

Retinal Nerve Fiber Layer Volume Measurements in Normal Children Using Spectral Domain Optical Coherence Tomography

• Lee DE
• Shin JW
• Lim HW
• Shin YU
• Kang MH
• Cho HY
• Seong MC

• KMID: 2212724
• DOI: http://doi.org/10.3341/jkos.2016.57.5.800

Abstract

PURPOSE
To measure retinal nerve fiber layer (RNFL) volume in normal children using spectral domain optical coherence tomography (SD-OCT).
METHODS
This study included 79 eyes of 54 normal children between 4 and 15 years of age evaluated from February 2012 to November 2012. All participants underwent ocular examination and 3D-disc scanning using SD-OCT. RNFL volume was calculated between 2.5 and 5 mm diameter circles using the length, width, and height of each pixel derived from the RNFL thickness map with Matlab software. The relationship between RNFL volume and thickness was analyzed.
RESULTS
The RNFL volumes of the mean total, superior, nasal, inferior, and temporal areas were 1.48 ± 0.09 mm3, 0.45 ± 0.04 mm3, 0.29 ± 0.04 mm3, 0.46 ± 0.03 mm3, and 0.29 ± 0.04 mm3, respectively. Comparing RNFL volume and conventional circumpapillary RNFL thickness measured using built-in software, a strong correlation between mean total, superior, and inferior areas (R = 0.980, 0.953 and 0.932, respectively) and a moderate correlation between the nasal and temporal areas were observed (R = 0.545 and 0.514, respectively). The negative correlations between RNFL thickness and RNFL volumes of the mean total, superior, nasal, inferior, and temporal areas and age were not significant (p > 0.05).
CONCLUSIONS
This study reports RNFL volume measured from RNFL thickness map analysis in normal children. These data regarding RNFL volume of normal children may provide useful information for diagnosis and monitoring of pediatric glaucoma.

Keyword

Normal children; Retinal nerve fiber layer; Spectral domain optical coherence tomography; Volume

MeSH Terms

Child*
Diagnosis
Glaucoma
Humans
Nerve Fibers*
Retinaldehyde*
Tomography, Optical Coherence*
Retinaldehyde

Figure

• 

  Figure 1. A process for measuring retinal nerve fiber layer (RNFL) thickness of each pixel in the RNFL thickness map. The RNFL thickness map in the 6 × 6 mm2 (540 × 540 pixels) parapapillary area is converted to RGB color information (red arrow). The color scale bar is also converted to red, green and blue (RGB) color format (black arrow). Then, each color pixel (blue and violet boxes) in the RNFL thickness map is compared with the RGB dataset (black box) of the color scale bar, and the RGB difference is calculated. We define RGB difference as (Red map - Red bar)2 + (Green map - Green bar)2 + (Blue map - Blue bar)2. Each different minimal RGB position (pink and green boxes) is selected in the color scale bar and translated to the corresponding numeric RNFL thickness measurement. SD-OCT = spectral domain optical coherence tomography.

• 

  Figure 2. Three-dimensional (3-D) structure of retinal nerve fiber layer (RNFL). (A) 3-D RNFL structure as the integral of a number of cube pixels. (B) The RNFL volume as the sum of ‘(6/540) mm × (6/540) mm × (RNFL thickness of corresponding pixel/1,000) mm’ within the measuring area. (C) RNFL volume between the 2.5- and 5-mm diameter circles, and RNFL thickness on the 3.4-mm circle.

• 

  Figure 3. Retinal nerve fiber layer (RNFL) volume in children according to age. (A) Total mean RNFL volume. (B) Superior quadrant RNFL volume. (C) Nasal quadrant RNFL volume. (D) Inferior RNFL volume. (E) Temporal RNFL volume. ∗Correlation coefficient; †Statistical significance was tested using Person’s correlation test.

Reference

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