Retinal nerve fiber layer imaging with spectral-domain optical coherence tomography: a variability and diagnostic performance study.

PURPOSE To evaluate the effect of myopia on the peripapillary retinal nerve fiber layer (RNFL) thickness measured by Cirrus HD optical coherence tomography (OCT). METHODS Comprehensive ophthalmic examinations were performed, including measurement of visual acuity, refraction, and axial length on 269 subjects (age, 19-26 years) with no ophthalmic abnormality. Further, 200 x 200-cube optic disc scans of the subjects' eyes were obtained with Cirrus HD OCT. The RNFL thickness at 256 points of the RNFL thickness profile and the average RNFL thickness were recorded. The correlations between these values and the axial length and spherical equivalent (SE) of refractive errors were then analyzed by simple linear regression, before and after adjustment of the ocular magnification. RESULTS Before ocular magnification adjustment, the uncorrected average RNFL thickness decreased as the axial length increased and as the SE decreased. However, after the adjustment, the corrected average RNFL thickness exhibited no correlation with the spherical equivalent and a weak positive correlation with the axial length. Myopia also affected the RNFL thickness distribution. As the axial length increased and the spherical equivalent decreased, the thickness of the temporal peripapillary RNFL increased and that of the superior, superior nasal, inferior, and inferior nasal peripapillary RNFL decreased. CONCLUSIONS The axial length affected the average RNFL thickness, and myopia affected the RNFL thickness distribution. High myopes are likely to exhibit different RNFL distribution patterns. Since ocular magnification significantly affects the RNFL measurement in such patients, it should be considered in diagnosing glaucoma.

Effect of Myopia on the Thickness of the Retinal Nerve Fiber Layer Measured by Cirrus Hd Optical Coherence Tomography

Objective: To develop consensus recommendations for reporting of quantitative optical coherence tomography (OCT) study results. Methods: A panel of experienced OCT researchers (including 11 neurologists, 2 ophthalmologists, and 2 neuroscientists) discussed requirements for performing and reporting quantitative analyses of retinal morphology and developed a list of initial recommendations based on experience and previous studies. The list of recommendations was subsequently revised during several meetings of the coordinating group. Results: We provide a 9-point checklist encompassing aspects deemed relevant when reporting quantitative OCT studies. The areas covered are study protocol, acquisition device, acquisition settings, scanning protocol, funduscopic imaging, postacquisition data selection, postacquisition data analysis, recommended nomenclature, and statistical analysis. Conclusions: The Advised Protocol for OCT Study Terminology and Elements recommendations include core items to standardize and improve quality of reporting in quantitative OCT studies. The recommendations will make reporting of quantitative OCT studies more consistent and in line with existing standards for reporting research in other biomedical areas. The recommendations originated from expert consensus and thus represent Class IV evidence. They will need to be regularly adjusted according to new insights and practices.

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The APOSTEL recommendations for reporting quantitative optical coherence tomography studies

PURPOSE. To identify sex-related differences and age-related changes in individual retinal layer thicknesses in a population of healthy eyes across the lifespan, using spectral domain optical coherence tomography (SD-OCT). METHODS. In seven institutes in Japan, mean thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment (IS), and photoreceptor outer segment (OS) were measured using SD-OCT with a new automated segmentation protocol in 256 healthy subjects. RESULTS. Interoperator coefficients of variability for measurements of each layer ranged from 0.012 to 0.038. The RNFL, GCL, IPL, and INL were thinnest in the foveal area, whereas the OPLONL and OS were thickest in this area. Mean thicknesses of the INL and the OPLONL were significantly greater in men (P 0.002 and 0.001, respectively). However, mean RNFL thickness was greater in women (P 0.006). Thicknesses of the RNFL, GCL, IPL, INL, and IS correlated negatively with age. Thickness of the OPLONL was not correlated with age, and thickness of the OS correlated positively with age. Inner retinal (RNFLGCLIPL) thickness over the whole macula correlated negatively with age (P 0.001), but outer retinal (OPLONLISOS) thickness did not. Thicknesses of layers did not correlate with axial length. CONCLUSIONS. Macular layer thicknesses measured on SD-OCT images in healthy eyes showed significant variations by sex and age. These findings should inform macular layer thickness analyses in SD-OCT studies of retinal diseases and glaucoma. (Invest Ophthalmol Vis Sci. 2011;52:8769‐8779) DOI:10.1167/ iovs.11-8388

Effects of Age, Sex, and Axial Length on the Three-Dimensional Profile of Normal Macular Layer Structures

Glaucoma Profile and Predictors of Normal Ganglion Cell–Inner Plexiform Layer Thickness Measured with Frequency-Domain Optical Coherence Tomography Jean-Claude Mwanza, 1 Mary K. Durbin, 2 Donald L. Budenz, 1 Christopher A. Girkin, 3 Christopher K. Leung, 4 Jeffrey M. Liebmann, 5 James H. Peace, 6 John S. Werner, 7 and Gadi Wollstein, 8 on behalf of the Cirrus OCT Normative Database Study Group 9 P URPOSE . To describe the profile and identify the predictors of the ganglion cell–inner plexiform layer (GCIPL) thickness mea- sured with frequency-domain optical coherence tomography (FD-OCT) in normal eyes. M ETHODS . Two hundred eighty-two normal subjects underwent macular and optic disc scanning in both eyes with Cirrus high-definition (HD)-OCT (Carl Zeiss Meditec, Dublin, CA). Linear regression analyses were performed to determine the association between GCIPL thickness and age, sex, ethnicity (Europeans, Africans, Hispanics, Asians, and Indians), eye lat- erality, refraction, intraocular pressure, axial length, central corneal thickness, mean retinal nerve fiber layer (RNFL) thick- ness, disc and rim areas, cup-to-disc area, vertical and horizon- tal cup-to-disc diameter ratios, vertical rim thickness, and OCT signal strength. R ESULTS . The mean (⫾SD) age was 46.2 ⫾ 16.9 years (range, 18 – 84 years). The mean and minimum GCIPL thicknesses (⫾SD) were 82.1 ⫾ 6.2 and 80.4 ⫾ 6.4 ␮ m, respectively. There were significant differences in GCIPL thickness between mac- ular sectors (P ⬍ 0.05), except between the superotemporal and inferonasal sectors (P ⫽ 0.63). The superonasal sector had the thickest and the inferior had the thinnest GCIPL. The From the 1 Bascom Palmer Eye Institute, Miami Miller School of Medicine, University of Miami, Miami, Florida; 2 Carl Zeiss Meditec, Inc., Dublin, California; the 3 Department of Ophthalmology, University of Alabama, Birmingham, Alabama; the 4 Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China; the 5 Department of Ophthalmology, New York Univer- sity School of Medicine, New York, New York; the 6 Department of Ophthalmology and Vision Science, United Medical Research Institute, Inglewood, California; the 7 Department of Ophthalmology and Visual Science, University of California Davis, Sacramento, California; and the UPMC Eye Center, Eye and Ear Institute, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. The participating investigators and their centers are listed in the Appendix. Supported by an unrestricted grant from Carl Zeiss Meditec, Inc. (Dublin, CA). Submitted for publication May 17, 2011; revised July 17, 2011 and August 11, 2011; accepted August 17, 2011. Disclosure: J.-C. Mwanza, Carl Zeiss Meditec (F), Optovue (F), Heidelberg Engineering (F); M.K. Durbin, Carl Zeiss Meditec (E); D.L. Budenz, Carl Zeiss Meditec (F), Optovue (F), Heidelberg Engineering (F); C.A. Girkin, Carl Zeiss Meditec (F); C.K. Leung, Carl Zeiss Meditec (F, C, R); J.M. Liebmann, Carl Zeiss Meditec (F), Optovue (F, C), Heidelberg Engineering (F), Topcon (F, C); J.H. Peace, Carl Zeiss Meditec (F); J.S. Werner, Carl Zeiss Meditec (F); G. Wollstein, Carl Zeiss Meditec (F) Corresponding author: Donald L. Budenz, Bascom Palmer Eye Insti- tute, 900 NW 17th Street, Miami, FL 33136; dbudenz@med.miami.edu. GCIPL of the superior hemisphere was thicker than that of the inferior, and the nasal sector GCIPL was significantly thicker than the temporal one (P ⬍ 0.001). The average GCIPL did not differ between male and female subjects (P ⫽ 0.16) after adjustment for axial length and between ethnic groups (P ⫽ 0.41) after adjustment for age, axial length, and RNFL thick- ness. Significant predictors of mean GCIPL thickness were average RNFL thickness ( ␤ ⫽ 0.37, P ⬍ 0.001), age ( ␤ ⫽ ⫺0.083, P ⬍ 0.001), axial length ( ␤ ⫽ ⫺0.87, P ⫽ 0.001), and male sex ( ␤ ⫽ ⫺1.62, P ⫽ 0.005). C ONCLUSIONS . The independent factors associated with thinner GCIPL include thinner RNFL, older age, longer ocular axial length, and being male. Although the magnitude of the effect of age, axial length, and sex are small, these factors should be taken into account when interpreting Cirrus HD-OCT-based GCIPL thickness measurements. (Invest Ophthalmol Vis Sci. 2011;52:7872–7879) DOI:10.1167/iovs.11-7896 A better understanding of complex diseases, such as glau- coma, requires assessment of the various demographic, environmental, genetic, and ocular factors that are believed to be involved in their occurrence. Studies have shown that some classic risk factors, such as elevated intraocular pressure (IOP), are not sufficient to explain and/or predict the risk of devel- oping glaucoma. On the other hand, retinal nerve fiber layer (RNFL) thickness measured noninvasively by optical coher- ence tomography (OCT) is a reliable early marker of glaucoma risk and can predict the development of subsequent glaucoma- tous visual field defects. 1,2 Several studies have characterized the retinal and RNFL thickness profile in healthy eyes, 3,4 whereas others have, in addition, investigated the effect of demographic and ocular factors on these structures. 3,5–11 Because the pathogenesis of glaucoma involves the degeneration not only of axons, but also of cell bodies and dendrites, it is fundamental to know the normal thickness profile of the retinal ganglion cell (RGC) and the dendritic layers. The average macular ganglion cell–inner plexiform layer (GCIPL) thicknesses measured using Stratus OCT (Carl Zeiss Meditec, Dublin, CA) and ranging between 68 and 74.8 ␮ m have been reported in normal eyes. 12–16 How- ever, the limitations of these studies are that they included only a small number of eyes and did not provide sectoral thicknesses of GCIPL or explore the relationship between macular GCIPL thick- ness and demographic or ocular parameters. Although ethnicity, age, axial length, and disc area have been shown to be determi- nant factors of RNFL thickness, 4,7,9,11,17–19 it remains unknown whether these factors also have an effect on other retinal layers. The recent development of more powerful intraretinal segmen- tation algorithms for some commercially available spectral- domain OCT devices now allows quantitative measurement of Investigative Ophthalmology & Visual Science, October 2011, Vol. 52, No. 11 Copyright 2011 The Association for Research in Vision and Ophthalmology, Inc. Downloaded From: http://iovs.arvojournals.org/pdfaccess.ashx?url=/data/Journals/IOVS/933458/ on 02/10/2016

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Profile and predictors of normal ganglion cell-inner plexiform layer thickness measured with frequency-domain optical coherence tomography.

PURPOSE. To evaluate the relationship between retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) and the axial length/refractive error of the eye. METHODS. A total of 115 eyes of 115 healthy subjects, comprising 75 eyes with high myopia (spherical equivalent [SE] < -6.0 D) and 40 eyes with low to moderate myopia (SE between -6.0 D and -0.5D), were analyzed in this cross-sectional study. Total average and mean clock hour RNFL thicknesses were measured by OCT and compared between the two myopia groups. Associations between RNFL measurements and axial length and spherical equivalent were evaluated by linear regression analysis. RESULTS. The RNFL measurements were significantly lower in the high myopia group compared with those of the low-to-moderate myopia group at 12, 1, and 7 o'clock (right eye orientation). Apart from the temporal clock hours, significant correlations were evident between RNFL measurements and the axial length and spherical equivalent. The average RNFL thickness decreased with increasing axial length (r = -0.314, P = 0.001) and negative refractive power (r = 0.291, P = 0.002). A significant proportion of myopic eyes were classified as outside normal limits, with reference to the normative database. The most frequently abnormal sector was at 2 o'clock, where 16.5% of myopic eyes were outside normal limits. CONCLUSIONS. RNFL measurements vary with the axial length/ refractive error of the eye. Analysis of RNFL thickness in the evaluation of glaucoma should always be interpreted with reference to the refractive status. Although the normative database provided by OCT has been helpful in identifying ocular diseases involving the RNFL, it may not be reliable in the analysis of myopic eyes.

Daphne Ka-yee Cheng

Papers

Retinal nerve fiber layer measurements in myopia: An optical coherence tomography study.