Measurements and classification of visual field defects.

<p>(<b>A</b>–<b>C</b>) Type 1 optic disc drusen (ODD). (<b>A</b>) Type 1 ODD creates a nasal halo (red arrowheads). The Relative Disc Index is defined as the ratio between the longest halo diameter (<i>a</i>) and foveo-disc diameter (<i>b</i>), and it represents the distortion induced by ODD on the enface plane. (<b>B</b>) B-scan spectral-domain optical coherence tomography (SD-OCT) image with demarcated border (yellow dotted line). (<b>C</b>) Same image of (<b>B</b>) with arrows indicative of the ODD height (<i>c</i>) and the Bruch’s membrane opening (BMO) diameter (<i>d</i>). The ODD height reflects the distortion induced by ODD in the axial plane. B-scan images with the largest ODD height and BMO diameter were used for their measurement, respectively. (<b>D</b>–<b>F</b>) Type 2 ODD. (<b>D</b>) The Relative Disc Index is defined in the same manner. Note the ODD are detectable through the funduscopic examination (red arrowheads) (<b>E</b>) B-scan SD-OCT image. Type 2 ODD composed of two portions: satellite lesions (red arrowheads) characterized by highly reflective border and low internal reflectance, and surrounding type 1 ODD-like deposits (yellow dotted lines). (<b>E</b>) Same image of (<b>F</b>) with arrows indicative of the ODD height (<i>c</i>) and the BMO diameter (<i>d</i>). The ODD height was measured from the most protruded part of the entire mass (satellite lesions and surrounding tissue) in the same manner.</p

Factors associated with visual field defects of optic disc drusen

<div><p>Purpose</p><p>To investigate the prevalence and risk factors for visual field defect in patients with optic disc drusen (ODD).</p><p>Methods</p><p>We assessed the visual field status of patients with ODD whose diagnosis were confirmed by spectral-domain optical coherence tomography (SD-OCT). Visual field defects were classified as normal, enlarged blind spot, or other defects. ODD were classified into either type 1 (without hyperreflective border and heterogenic internal reflectance) or type 2 (with hyperreflective border and lower internal reflectance). The prevalence and risk factors for each visual field defect was analyzed using logistic regression analysis and classification and regression tree (CART) modeling.</p><p>Results</p><p>Of the 40 eyes with ODD, 33 (83%) eyes were categorized as type 1 and 7 (17%) eyes were categorized as type 2 ODD. Regarding the visual field defects, 19 (48%) eyes showed normal visual field, 11 (28%) eyes showed enlarged blind spot, and 9 (24%) eyes showed other defects. The latter was more frequent in type 2 ODD (<i>P</i> = 0.001). Logistic regression analysis revealed that the factor associated with other defects was the thinning of the average retinal nerve fiber layer (RNFL) (per 10 μm decrease, OR = 3.436, <i>P</i> = 0.004), and the factor associated with enlarged blind spot was the height of ODD (per 100 μm increase, OR = 3.956, <i>P</i> = 0.023). CART modeling revealed that the average RNFL thickness lesser than 85.5 μm, and then the ODD height larger than 348 μm were the best split-up factors for predicting the type of visual field defects.</p><p>Conclusions</p><p>In this study, one-quarter of ODD patients showed abnormal visual field defect other than enlarged blind spot. These other visual field defects appeared to be associated with the axonal loss in the eyes with type 2 ODD.</p></div

Logistic regression analysis revealing the risk factors of each type of visual field defect.

<p>Logistic regression analysis revealing the risk factors of each type of visual field defect.</p

Types of visual field defects.

<p>(<b>A</b>) normal visual field, (<b>B</b>) enlarged blind spot, (<b>C</b>) other defects, and (<b>D</b>) bundle defect from the left respectively. The bundle defect is defined when other defects are connected to the blind spots. Please note that Humphrey visual field (HVF) test 30–2 strategy was used to ensure that no other defects were present in cases with normal visual field or enlarged blind spot.</p

Patients’ characteristics by the types of optic disc drusen and visual field defects.

<p>Patients’ characteristics by the types of optic disc drusen and visual field defects.</p

Sample cases of each type of visual field defect.

<p>(<b>A</b>–<b>C</b>) Other defects in the eye with type 2 ODD. (<b>A</b>) Fundus photography and SD-OCT image (inset). Highly reflective border is observed in the B-scan SD-OCT image, and ODD detectable through the funduscopic examination. A long arrow indicates where the SD-OCT scans. Short arrows point to the temporal margins of RNFL thinning. (<b>B</b>) Gray scale image of HVF. (<b>C</b>) Pattern deviation map shows superior nasal step and inferior defect (red arrows). corresponded to the areas of RNFL thinning in (<b>A</b>). Superior RNFL defect existed further from the foveo-disc axis (yellow arrows), thereby inferior visual field defect located further from the horizontal axis (red arrows). The location of visual field defect corresponded to the location of RNFL defect in the Garway-Heath map [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196001#pone.0196001.ref022" target="_blank">22</a>]. (<b>D</b>–<b>F</b>) Enlarged blind spot in the eye with type 1 ODD. (<b>D</b>) Fundus photography and SD-OCT image (inset). A long arrow indicates where the SD-OCT scans. Short arrows point to the superonasally located ODD. (<b>E</b>) Gray scale image of HVF. (<b>F</b>) Pattern deviation map shows the enlarged blind spot (red arrow). The enlargement proceeds in the inferotemporal direction, which is corresponded to the superonasal location of ODD.</p

Receiver operating characteristic (ROC) curves of the GCIPL thickness in the outer temporal zone obtained using the ROC regression model by a generalized linear regression model.

<p>ROC curve obtained using the ROC regression model (<b>A</b>), and that obtained at fixed visual field mean deviations (MDs) of –6.0 dB (<b>B</b>), and –12.0 dB (<b>C</b>). Although the difference in the area under the ROC curve (AUC) between the two systems decreases as MD decreases, the AUCs of SD-OCT remain larger than those of SS-OCT.</p

Path diagram of structural equation model (SEM) for comparison between the measurements from DRI SS-OCT and Spectralis SD-OCT.

<p>Scale represents relative bias.</p

Retinal thickness maps showing mean total retinal layer thicknesses in each of the nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields as measured using spectral-domain optical coherence tomography (SD-OCT; A) and swept-source optical coherence tomography (SS-OCT; B). (C, D) B-scans obtained at the center of the macula (<i>green lines</i> in A and B, respectively). Note that the outer boundary is the retinal pigment epithelium in SD-OCT (<i>red line</i>, C), while it is the junction between the photoreceptor outer segment and retinal pigment epithelium in SS-OCT (<i>green line</i>, D).

<p>Retinal thickness maps showing mean total retinal layer thicknesses in each of the nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields as measured using spectral-domain optical coherence tomography (SD-OCT; A) and swept-source optical coherence tomography (SS-OCT; B). (C, D) B-scans obtained at the center of the macula (<i>green lines</i> in A and B, respectively). Note that the outer boundary is the retinal pigment epithelium in SD-OCT (<i>red line</i>, C), while it is the junction between the photoreceptor outer segment and retinal pigment epithelium in SS-OCT (<i>green line</i>, D).</p

Calibration plots (<i>solid lines</i>) of the ganglion cell layer plus inner plexiform layer (GCIPL) (A) and macular retinal nerve fiber layer (mRNFL) (B) thicknesses (μm) for DRI SS-OCT and Spectralis SD-OCT.

<p><i>Dotted lines</i> indicate the 45-degree reference lines of equality. POAG, primary open-angle glaucoma; CF, central fovea; IS, inner superior; IN, inner nasal; II, inner inferior; IT, inner temporal; OS, outer superior; ON, outer nasal; OI, outer inferior; OT, outer temporal.</p