Determination of foveal location using scanning laser polarimetry

VanNasdale, Dean A.; Elsner, Ann E.; Weber, Anke; Miura, Masahiro; Haggerty, Bryan P.

doi:10.1167/9.3.21

Cited by 18 publications

(24 citation statements)

References 70 publications

(92 reference statements)

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“…7,8,10,14,16,36 The GDx uses a 780-nm linearly polarized light source to scan a raster on the retina. The instrument used in this study has a fixed birefringent element with a magnitude of 60 nm (singlepass retardance) and a fast axis oriented at 15 deg nasally downward to compensate for corneal birefringence.…”

Section: Methodsmentioning

confidence: 99%

“…Structures that cause multiple scattering, such as the RPE, or pathology occurring in the deeper layers of the retina, are visualized easily in images emphasizing light that is depolarized. 7-10 Phase retardation, or birefringence changes, can be used to emphasize the retinal nerve fiber layer, 11-13 the photoreceptor axons in the central macula that constitute the Henle fiber layer, 14-16 and the sclera. 15,17-20 Thus, by selecting specific polarization conditions an image can be formed to emphasize retinal birefringence or features that scatter light, as well as to increase image contrast.…”

mentioning

confidence: 99%

“…The bow tie pattern has been shown to accurately localize the foveal position in normal individuals over a wide range of ages. 16 This technique is potentially useful when foveal structure is obscured by highly reflective, pathological features in the deeper retinal layers and RPE, or the foveal pit is obscured by retinal thickness changes. In addition to being an intrinsic marker for the position of the central macula, the birefringence pattern of the Henle fiber layer may also act as a surrogate indicator of photoreceptor structure in the presence of pathology associated with AMD.…”

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confidence: 99%

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Foveal Localization in Non-Exudative AMD Using Scanning Laser Polarimetry

VanNasdale

Elsner²,

Kohne³

et al. 2012

Optometry and Vision Science

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Purpose To determine whether custom scanning laser polarimetry (SLP) images, differing in polarization content, can be used to accurately localize the fovea in the presence of non-exudative age-related macular degeneration (AMD). To determine whether alterations to the foveal structure in non-exudative AMD significantly disrupts the birefringent Henle fiber layer, responsible for the macular cross pattern in some SLP images. To determine whether phase retardation information, specifically color-coded information representing its magnitude and axis, allow better foveal localization than images including retardation amplitude only. Methods SLP images were acquired in 25 AMD subjects and 25 age-matched controls. Raw data were used to generate 5 custom image types differing in polarization content. The foveal location was marked by 3 graders in each image type for each subject. The difference in variability was compared between the AMD subjects and matched controls. We further determined whether the orientation of Henle fiber layer phase retardation improved localization in 10 subjects with the highest variability in images including only phase retardation amplitude. Results Images that differed in polarization content led to strikingly different visualizations of AMD pathology. The Henle fiber layer remained sufficiently intact to assist in fovea localization in all subjects, but with more variability in the AMD group. For both the AMD and matched control group, images containing birefringence amplitude and orientation information reduced the amount of intra-grader, inter-grader, and inter-image variability for estimating foveal location. Conclusions The disruption in Henle fiber birefringence was evident in the eyes with AMD, but nevertheless was sufficient to help in foveal localization despite macular pathology. Phase retardation amplitude and axis of orientation can be a useful tool in foveal localization in patients with AMD.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Foveal Localization in Non-Exudative AMD Using Scanning Laser Polarimetry

VanNasdale

Elsner²,

Kohne³

et al. 2012

Optometry and Vision Science

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“…A confocal scanning laser polarimeter (GDx, Laser Diagnostic Technologies/Carl Zeiss Meditec; Dublin, CA) was used to acquire images of the central macula using the acquisition and analysis method described previously (Burns et al, 2003; Elsner et al, 2007; Mellem-Kairala et al, 2005; VanNasdale et al, 2009; Weber et al, 2004; Weber et al, 2007). The GDx uses a 780-nm linearly polarized near infrared light source to scan a 15 × 15 deg raster pattern on the retina.…”

Section: Methodsmentioning

confidence: 99%

“…The interaction of the phase retardation of the Henle fiber layer with polarized light has been modeled (Brink & van Blokland, 1988). This macular cross pattern has been used qualitatively to localize the fovea in normal subjects (VanNasdale et al, 2009); monitor fixation and eye tracking in infants and young subjects (Gramatikov et al, 2006; Gramatikov et al, 2007; Hunter et al, 2004; Hunter et al, 1999; Hunter et al, 2003; Nassif et al, 2003); and characterize damage due to age-related macular degeneration (Elsner et al, 2007; Weber et al, 2007); and central serous chorioretinopathy (Miura et al, 2005). …”

Section: Introductionmentioning

confidence: 99%

Foveal phase retardation changes associated with normal aging

et al. 2011

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This study quantified normal age-related changes to the photoreceptor axons in the central macula using the birefringent properties of the Henle fiber layer. A scanning laser polarimeter was used to acquire 15 × 15 deg macular images in 120 clinically normal subjects, ranging in age from the third decade to the eighth. Raw image data of the macular cross were used to compute phase retardation maps associated with Henle fiber layer. Annular regions of interest ranging from 0.25 to 3 deg eccentricity and centered on the fovea were used to generate intensity profiles from the phase retardation data, which were then analyzed using sine curve fitting and Fast Fourier Transform (FFT). The amplitude of a 2f sine curve was used as a measure of macular phase retardation magnitude. For FFT analysis, the 2f amplitude, as well as the 4f, were normalized by the remaining FFT components. The amplitude component of the 2f curve fit and the normalized 2f FFT component decreased as a function of age, while the eccentricity of the maximum value for the normalized 2f FFT component increased. The phase retardation changes in the central macula indicate structural alterations in the cone photoreceptor axons near the fovea as a function of age. These changes result in either fewer cone photoreceptors in the central macula, or a change in the orientation of their axons. This large sample size demonstrates systematic changes to the central cone photoreceptor morphology using scanning laser polarimetry.

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Concentric Macular Rings Sign in Patients With Foveal Hypoplasia

2014

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IMPORTANCEWe describe a sign that can be used as a rapid and noninvasive adjunct to aid in the diagnosis of foveal hypoplasia.OBJECTIVE To describe a concentric macular rings sign found on infrared reflectance (IRR) images in patients with foveal hypoplasia. DESIGN, SETTING, AND PATIENTSWe studied 13 patients with foveal hypoplasia (7 with ocular albinism [OA], 5 with oculocutaneous albinism [OCA], and 1 with aniridia) at a tertiary ophthalmology center with access to electrodiagnostic services from February 18, 2009, through April 9, 2013. MAIN OUTCOMES AND MEASURESAll patients and an age-matched control participant underwent a complete clinical examination, electroretinography (full field and pattern), visual evoked potentials, fundus autofluorescence IRR, and optical coherence tomography (OCT). One patient with OA and the control participant also underwent scanning laser polarimetry with variable corneal compensation (GDx VCC).RESULTS Thirteen patients (6 girls and 7 boys), with a mean age of 5.8 years (range, 3-11 years), were included in the study. Seven patients were diagnosed as having OA and had minimal clinical signs (fine nystagmus in 2 patients and subtle iris transillumination in 5 patients). Five patients with OCA and 1 with aniridia were also included. In 12 patients, OA and OCA were confirmed with 5-channel visual evoked potentials (optic nerve misrouting). Whenever OCT was performed, foveal hypoplasia was indicated by the lack of foveal dip. The macula lacked the foveal attenuation normally seen with fundus autofluorescence, and a concentric macular rings reflex was seen with IRR in all 13 patients and with GDx VCC in 1 patient. A normal bowtie reflex was seen with IRR and GDx VCC in the age-matched control participant.CONCLUSIONS AND RELEVANCE Our findings suggest that concentric macular rings seen on IRR or GDx VCC can occur in patients with foveal hypoplasia and can therefore aid in the diagnosis, especially in patients with minimal clinical signs (mild OA) or in cases in which OCT cannot be performed (young patients or patients with high-amplitude nystagmus).

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Determination of foveal location using scanning laser polarimetry

Cited by 18 publications

References 70 publications

Foveal Localization in Non-Exudative AMD Using Scanning Laser Polarimetry

Foveal Localization in Non-Exudative AMD Using Scanning Laser Polarimetry

Foveal phase retardation changes associated with normal aging

Concentric Macular Rings Sign in Patients With Foveal Hypoplasia

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