Readme: Descriptive data for USN Research Data Archive



Dataset generated by Hilde R. Pedersen, Stuart J. Gilson and Rigmor C. Baraas





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GENERAL INFORMATION

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TITLE FOR THE DATASET



Rod and cone dark adaptation in congenital aniridia and its association

with retinal structure



OCT_RetinalLayers_Aniridia:

Measured retinal layer thicknesses for 20 persons with congenital aniridia







CONTACT INFORMATION



Dr. Hilde R. Pedersen

University of South-Eastern Norway

Hasbergsvei 36

3616 Kongsberg

Norway

hilde.r.pedersen@usn.no





DATA COLLECTION

2015–2019 in Norway





LANGUAGE

English





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FILE INFORMATION

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The files are comma-separated text files and can be imported into R

statistical software, Excel or other CSV-compatible programs.



For each participant, layers and thicknesses are shown with respect to lateral

eccentricity from the foveal center. The thickness values are extracted and

averaged for each ≈ 100µm region (50µm in the foveal center) within ±3000 µm

(total 6 mm) eccentricity from the foveal center.



All thickness measurements are in microns (µm). Retinal eccentricities from

the foveal center are in microns (Ecc). Negative numbers represent the nasal

meridian and positive numbers the temporal meridian.







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METHODOLOGY

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SD-OCT images were acquired with the Heidelberg Spectralis OCT2 (Heidelberg

Engineering GmbH, Heidelberg; Germany).



Retinal layers were segmented at:



 o the anterior egde of the inner limiting membrane (ILM)

 o the posterior boundary of the inner plexiform layer (IPL)

 o the outer plexiform layer (OPL)

 o the center of the external limiting membrane (ELM)

 o the ellipsoid zone (EZ)

 o the interdigitation zone (IZ)

 o and the posterior boundary RPE-Bruch’s Membrane (RPE) band



using semi-automatic custom software.  The outer retinal layers are a

combined measurement of the outer nuclear layer, photoreceptor inner and

outer segments, and RPE. Inner retinal layers is a combined measurement of

the retinal nerve fiber layer, ganglion cell layer and inner plexiform layer.



Thickness of retinal layers were calculated and defined as follows:

  Retinal thickness (RT): ILM - RPE

  Outer retinal layers (ORL): OPL - RPE

  Inner retinal layers (IRL): ILM - IPL

and represent the distance (measured in pixels, but shown in microns using

the Spectralis' axial scaling of 3.87 microns per pixel) between the

prescribed layers for the single 1-pixel-wide A-scan lying nearest to the

specified eccentricity.



The lateral scaling (microns-per-degree) for each participant was corrected

for retinal magnification based on individual ocular biometry, calculated

with a 4-surface schematic eye model (Li KY, Tiruveedhula P, Roorda A.

Intersubject variability of foveal cone photoreceptor density in relation to

eye length. Invest Ophthalmol Vis Sci. 2010;51:6858–6867).  Eccentricities

("Ecc" column) are based on the lateral scaling computed for each

participant, and an expert-derived foveal centre.



The different macular regions, along the nasal and temporal meridians,

were defined as:

  Foveal center: central 50 μm

  Parafoveal region: 0.5–1.5 mm retinal eccentricity

  Perifoveal region: 1.5–3.0 mm retinal eccentricity