Journal: PLoS ONE
Article Title: Hemisphere opposite to vascular trunk deviation is earlier affected by glaucomatous damage in myopic high-tension glaucoma
Figure Lengend Snippet: Measurement of position of central vascular trunk as surrogate of lamina cribrosa (LC) shift. ( A ) Red-free fundus photo. Diffuse retinal nerve fiber layer (RNFL) loss was observed in both hemispheres but was more severe in the inferior hemisphere. An infrared image obtained by spectral-domain optical coherence tomography (SD-OCT) is transposed to show the margin of the Bruch’s membrane opening (BMO) and the foveal-BMO axis. SD-OCT uses 24 radial scan images to delineate the BMO margin (red dots) and calculate the foveal-BMO axis. ( B ) Magnified view of peripapillary area. The red dots indicate the BMO margin, and the green line is the reference line. The angular deviation of the vascular trunk (α) is measured clock-wise, with the nasal horizontal midline as 0°. A positive value indicates the superior location, and a negative value indicates the inferior location relative to the reference line. From the BMO center, the distances are measured to the vascular trunk ( a ), and to the BMO margin in the same direction ( b ). The ratio of these distances is defined as the ‘shift index’ ( a / b ), which is used to measure the extent of shift. The angular location of maximum width of β-zone parapapillary atrophy (PPA) (β) is measured clock-wise from the reference line (green line), with the temporal horizontal midline as 0°. A positive value indicates the superior location and a negative value indicates the inferior location relative to the reference line. ( C ) Disc photograph. The dotted line indicates the location of the SD-OCT scan, targeted to the central retinal vascular trunk (arrowhead). ( D ) Cross-sectional image of SD-OCT clearly showing emergence of central retinal vascular trunk (arrowhead). The LC depth is measured as the vertical distance from the BMO plane (green reference line) to the vascular trunk (yellow double arrows). The blue-dotted line indicates the anterior LC surface margin. ( E ) The Humphrey visual field result shows scotoma only in the superior hemisphere.
Article Snippet: All of the participants underwent a full ophthalmologic examination that included best-corrected visual acuity (BCVA) assessment, refraction, slit-lamp biomicroscopy, Goldmann applanation tonometry, gonioscopy, dilated funduscopic examination, keratometry (RKT-7700; Nidek, Hiroshi, Japan), axial length measurement (IOLMaster version 5; Carl Zeiss Meditec, Dublin, California, USA), disc photography and red-free fundus photography (TRC-NW8; Topcon, Tokyo, Japan), spectral-domain optical coherence tomography (SD-OCT; Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany) and standard automated perimetry (Humphrey Field Analyzer II 750, 24–2 Swedish Interactive Threshold Algorithm; Carl-Zeiss Meditec, Dublin, CA, USA).