Optic Disc Measurements in Myopia with Optical Coherence Tomography and Confocal Scanning Laser Ophthalmoscopy

Leung, Christopher Kai-Shun; Cheng, Arthur C.K.; Chong, Kelvin; Leung, KY; Mohamed, Shaheeda; Lau, Charles Sing Lok; Cheung, Carol Y.; Chu, Geoffrey C.P; Lai, Robin Kit-Ho; Pang, Calvin Chi Pui; Lam, Dennis Shun Chiu

doi:10.1167/iovs.06-1315

Cited by 137 publications

(123 citation statements)

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“…The relationship between the measured size of the OCT image and the actual fundus size imaged was also described using Littmann's formula. 20 The main finding of that study was that the optic disc area increases with axial length and myopic refraction. For each millimeter increase in axial length, the optic disc area increased by 0.095 mm 2 .…”

Section: Discussionmentioning

confidence: 92%

“…10 Similarly, measurement of the optic disc size has an important bearing on the evaluation of optic nerve diseases and anomalies. Leung et al 20 used a Stratus OCT instrument to evaluate associations between optic disc area and axial length/spherical equivalent. The relationship between the measured size of the OCT image and the actual fundus size imaged was also described using Littmann's formula.…”

Section: Discussionmentioning

confidence: 99%

“…For each millimeter increase in axial length, the optic disc area increased by 0.095 mm 2 . 20 Huang et al 14 also studied the relationship between RNFL thickness, optic disc size, and image magnification using an approach based on axial length only. In that study, after accounting for the effect of magnification, RNFL thickness was no longer dependent on axial length.…”

Section: Discussionmentioning

confidence: 99%

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Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

Sampson

Gong

et al. 2017

Invest. Ophthalmol. Vis. Sci.

235

227

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Citation: Sampson DM, Gong P, An D, et al. Axial length variation impacts on superficial retinal vessel density and foveal avascular zone area measurements using optical coherence tomography angiography. Invest Ophthalmol Vis Sci. 2017;58:3065-3072. DOI:10.1167/iovs.17-21551 PURPOSE. To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). METHODS.Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 3 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated.RESULTS. Forty subjects were enrolled and the median (range) age of the participants was 30 (18-74) years. The mean (range) spherical equivalent refractive error was À1.65 (À8.00 to þ4.88) diopters and mean (range) axial length was 24.42 mm (21.27-28.85). Images from 13 eyes were excluded due to poor image quality leaving 67 for analysis. Relative changes in foveal and parafoveal SRVD and FAZA after correction ranged from À20% to þ10%, À3% to þ2%, and À20% to þ51%, respectively. Image size correction in measurements of foveal SRVD and FAZA was greater than 5% in 51% and 74% of eyes, respectively. In contrast, 100% of eyes had less than 5% correction in measurements of parafoveal SRVD.CONCLUSIONS. Ocular biometry should be performed with OCTA to correct image magnification error induced by axial length variation. We advise caution when interpreting interocular and interindividual comparisons of SRVD and FAZA derived from OCTA without image size correction.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

Sampson

Gong

et al. 2017

Invest. Ophthalmol. Vis. Sci.

235

227

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“…[17][18][19][20] Thus, the formula for disc area correction was as follows: corrected disc area ¼ 3:382 2 3 0:01306 2 3ðAL À 1:82Þ 2 3ðcomputed SD À OCT disc areaÞ:…”

Section: Estimation Of Dh Areamentioning

confidence: 99%

Effect of Focal Lamina Cribrosa Defect on Disc Hemorrhage Area in Glaucoma

Kim

Jeoung

Park

2016

Invest. Ophthalmol. Vis. Sci.

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Citation: Kim YK, Jeoung JW, Park KH. Effect of focal lamina cribrosa defect on disc hemorrhage area in glaucoma. Invest Ophthalmol Vis Sci. 2016;57:899-907. DOI:10.1167/ iovs.15-18389 PURPOSE. The purpose of this study was to evaluate the association between focal lamina cribrosa defect (FLCD) and the topographic characteristics of disc hemorrhage (DH), including area and location.METHODS. We enrolled a total of 98 primary open-angle glaucoma eyes with DH (98 subjects). In vivo lamina cribrosa (LC) images were obtained by swept-source optical coherence tomography (SS-OCT) immediately following the detection of DH. Two masked graders identified FLCD (laminar holes or disinsertions >100 lm in diameter and >30 lm in depth), defined by a customized protocol using en face images and 12 radial-orientation raster scans of SS-OCT. En face image/stereo-disc photography overlay images were evaluated to determine the spatial relationship between the respective FLCD and DH locations. A method of comparing the disc area and DH area pixel numbers was used to estimate the DH area.RESULTS. Sixty-eight of 98 eyes with DH (68.4%) had at least one FLCD. Thirty-eight of those 68 eyes with DH and at least one FLCD (55.9%) had a DH corresponding to the FLCD location (within one-half clock-hour distance from the midline). The FLCD-correspondent DHs (39 DHs) showed significantly larger areas (0.092 6 0.030 mm 2 ; P < 0.001) and more proximally located proximal ends (P < 0.028) than the noncorresponding ones (33 DHs; 0.065 6 0.024 mm 2 of area).CONCLUSIONS. The DHs that correspond to FLCD location tend to have larger areas and to be more proximally located than those without correspondence. This suggests that FLCD might affect the topographic characteristics of DH.

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“…This could be explained by the possibility that small disc area was related to long AL and myopia because OCT might have methodological artifacts. Some investigators have reported that AL might contribute in part to smaller disc area in myopic eyes when the magnification effect was not corrected in OCT. 33,34 Because this study also did not adjust the magnification effect, long AL might make disc size appear small on OCT. However, Kim et al 35 did not find significant correlation between AL and small disc using SD-OCT in their study, and the specific characteristics of cluster 3 were not only long AL and myopia but also younger age, compared with the other groups.…”

Section: Discussionmentioning

confidence: 98%

A Hierarchical Cluster Analysis of Normal-Tension Glaucoma Using Spectral-Domain Optical Coherence Tomography Parameters

Bae

Lee

et al. 2015

Journal of Glaucoma

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Purpose: Normal-tension glaucoma (NTG) is a heterogenous disease, and there is still controversy about subclassifications of this disorder. On the basis of spectral-domain optical coherence tomography (SD-OCT), we subdivided NTG with hierarchical cluster analysis using optic nerve head (ONH) parameters and retinal nerve fiber layer (RNFL) thicknesses.Patients and Methods: A total of 200 eyes of 200 NTG patients between March 2011 and June 2012 underwent SD-OCT scans to measure ONH parameters and RNFL thicknesses. We classified NTG into homogenous subgroups based on these variables using a hierarchical cluster analysis, and compared clusters to evaluate diverse NTG characteristics.Results: Three clusters were found after hierarchical cluster analysis. Cluster 1 (62 eyes) had the thickest RNFL and widest rim area, and showed early glaucoma features. Cluster 2 (60 eyes) was characterized by the largest cup/disc ratio and cup volume, and showed advanced glaucomatous damage. Cluster 3 (78 eyes) had small disc areas in SD-OCT and were comprised of patients with significantly younger age, longer axial length, and greater myopia than the other 2 groups.Conclusions: A hierarchical cluster analysis of SD-OCT scans divided NTG patients into 3 groups based upon ONH parameters and RNFL thicknesses. It is anticipated that the small disc area group comprised of younger and more myopic patients may show unique features unlike the other 2 groups.Key Words: normal-tension glaucoma, hierarchical cluster analysis, spectral domain optical coherence tomography (J Glaucoma 2015;24:328-333) N ormal-tension glaucoma (NTG) is an optic neuropathy characterized by glaucomatous optic disc excavation and corresponding retinal nerve fiber layer (RNFL) change with intraocular pressure (IOP) in the statistically normal range. NTG is a common form of open-angle glaucoma throughout the world, but there are still many unanswered questions regarding the heterogenous feature of NTG.First, NTG is considered to have various pathophysiologies. IOP has been well known as the predominant risk factor in NTG, despite controversy, 1,2 and despite IOP being statistically within the normal range. High prevalence of disc hemorrhage in NTG suggested that the pathophysiology of NTG may be related to a vascular component. [3][4][5][6] Association between nocturnal hypotension and NTG suggested the importance of ocular blood perfusion, 7-9 and the vasospastic mechanism was thought to play an important role in both migraine and NTG. [10][11][12] Many previous studies also showed that several autoimmune dysfunctions may be possible etiologies of NTG. [13][14][15][16][17] In addition, the similarities between NTG and hereditary optic neuropathy such as Leber hereditary optic neuropathy and dominant optic atrophy have been reported in previous studies. 18,19 Second, the rate of progression also seems to be highly variable in NTG. In the Collaborative Normal Tension Glaucoma Study, 20 about half of NTG patients without treatment showed recognizable progression, but a...

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Optic Disc Measurements in Myopia with Optical Coherence Tomography and Confocal Scanning Laser Ophthalmoscopy

Cited by 137 publications

References 25 publications

Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

Effect of Focal Lamina Cribrosa Defect on Disc Hemorrhage Area in Glaucoma

A Hierarchical Cluster Analysis of Normal-Tension Glaucoma Using Spectral-Domain Optical Coherence Tomography Parameters

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