Choroidal structure determined by binarizing optical coherence tomography images in eyes with reticular pseudodrusen

Figures & data

Table 1 Characteristics of eyes with RPD and those of the control

Characteristics	Eyes with RPD (n=20)	Controls (n=35)	P-valuea
Mean age (years)	82.3±4.2	81.5±6.0	0.648
Mean IOP (mmHg)	12.8±1.8	14.1±2.8	0.061
Refractive error, spherical equivalent (D)	−0.20±1.54	−0.24±1.62	0.923
BCVA (logMAR)	0.11±0.18	0.23±0.13	<0.05

Notes: All values are expressed as mean ± standard deviation (range).

a Unpaired t-test.

Abbreviations: RPD, reticular pseudodrusen; IOP, intraocular pressure; BCVA, best-corrected visual acuity; logMAR, logarithm of the minimal angle of resolution.

Figure 1 Subfoveal choroidal areas of EDI-OCT image in eyes with RPD and control eyes.

Notes: The choroidal, luminal, and stromal areas in eyes with RPD were significantly smaller than those of the control eyes (*P=0.001, unpaired t-test).
Abbreviations: EDI-OCT, enhanced depth imaging optical coherence tomography; RPD, reticular pseudodrusen.

Table 2 Results of choroidal binarization to quantify the total, luminal, and stromal choroidal areas in patients with RPD and in control subjects

	Eyes with RPD (n=20)	Controls (n=35)	P-valuea
Total choroidal area (µm^2)	193,370.4±53,653.0	273,915.6±78,764.4	0.001
Luminal area (µm^2)	127,505.7±35,612.8	183,152.2±55,666.4	0.001
Stromal area (µm^2)	65,864.6±21,416.0	90,763.3±28,392.0	0.003
Luminal ratio	0.66±0.05	0.66±0.05	0.6

Notes: All values are expressed as mean ± standard deviation (range).

a Unpaired t-test.

Abbreviation: RPD, reticular pseudodrusen.

Figure 2 EDI-OCT images of an eye with RPD and a control eye.

Notes: The EDI-OCT image of the eye with RPD (A) was converted to a binary image (C) by using the ImageJ software. An EDI-OCT image of the control eye (B) was converted to a binary image (D). The choroidal area measured was 1,500 µm wide with the margins 750 µm nasal and 750 µm temporal to the fovea. Vertically, the area extended from the retinal pigment epithelium to the chorioscleral border. The yellow area is the measured area of the choroid (E and F).
Abbreviations: EDI-OCT, enhanced depth imaging optical coherence tomography; RPD, reticular pseudodrusen.