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Fourier domain optical coherence tomography to assess the iridocorneal angle and correlation study in a large Caucasian population.

Fernández-Vigo JI, García-Feijóo J, Martínez-de-la-Casa JM, García-Bella J, Arriola-Villalobos P, Fernández-Pérez C, Fernández-Vigo JÁ - BMC Ophthalmol (2016)

Bottom Line: Mean angle width measurements were smaller in women (p = 0.02).ACV emerged as the main determinant of TIA (R(2) = 0.705; p < 0.001).In this Caucasian population, strong correlation was detected between FD-OCT anterior angle measurements and ACV, ACD, spherical refractive error and sex, emerging the ACV as the main determinant of TIA.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria San Carlos (IdISSC), c/Profesor Martín Lagos s/n, 28100, Madrid, Spain. jfvigo@hotmail.com.

ABSTRACT

Background: Recently, novel anatomic parameters that can be measured by optical coherence tomography (OCT), have been identified as a more objective and accurate method of defining the iridocorneal angle. The aim of the present study is to measure the iridocorneal angle by Fourier domain (FD) OCT and to identify correlations between angle measurements and subject factors in a large healthy Caucasian population.

Methods: A cross sectional study was performed in 989 left eyes of 989 healthy subjects. The iridocorneal angle measurements: trabecular-iris angle (TIA), angle opening distance (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur, were made using the FD-OCT RTVue®. Iris thickness was also measured. Correlations were examined between angle measurements and demographic and ocular factors. The main determinants of angle width were identified by multivariate linear regression.

Results: TIA could be measured in 94% of the eyes, and AOD500 and TISA500 in 92%. The means recorded were TIA 35.8 ± 12.2 degrees (range 1.5 to 76.1), AOD500 542.6 ± 285.4 μm (range 15 to 1755), and TISA500 0.195 ± 0.104 mm(2) (range 0.02 to 0.62). The correlation between the temporal and nasal quadrant was R = 0.902 for TIA. The reproducibility of measurements was excellent (intraclass correlation coefficient >0.947). Mean angle width measurements were smaller in women (p = 0.02). Correlation was detected between angle means and anterior chamber volume (ACV; R = 0.848), anterior chamber depth (ACD; R = 0.818), spherical error (R = -0.619) and age (R = -0.487), while no correlation was observed with Intraocular pressure (R = -0.052). ACV emerged as the main determinant of TIA (R(2) = 0.705; p < 0.001).

Conclusions: In this Caucasian population, strong correlation was detected between FD-OCT anterior angle measurements and ACV, ACD, spherical refractive error and sex, emerging the ACV as the main determinant of TIA.

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Related in: MedlinePlus

Examples of iridocorneal angle measurements made by Fourier Domain optical coherence tomography images. a Trabecular-iris angle (TIA) and (b) Angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur in a normal angle width. c and d TIA, AOD500 and TISA500 measurements in a narrow angle. e and (f) TIA, AOD500 and TISA500 measurements in a wide angle
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Fig1: Examples of iridocorneal angle measurements made by Fourier Domain optical coherence tomography images. a Trabecular-iris angle (TIA) and (b) Angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur in a normal angle width. c and d TIA, AOD500 and TISA500 measurements in a narrow angle. e and (f) TIA, AOD500 and TISA500 measurements in a wide angle

Mentions: The measurements made manually on these images were trabecular-iris angle (TIA), angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur [6, 11]. In Fig. 1, it may be seen how these measurements were made. TIA was measured by tracing a line from the angle recess to the Schwalbe’s line and another line on the surface of the iris to the perpendicular point on the Schwalbe’s line. AOD500 was measured as the perpendicular distance from the trabecular meshwork, 500 μm anteriorly from the scleral spur to the anterior iris surface. TISA500 was defined as the area bounded anteriorly by the AOD, posteriorly by a line drawn from the scleral spur perpendicular to the plane of the inner scleral wall to the opposing iris, superiorly by the inner corneoscleral wall, and inferiorly by the iris surface. Using this instrument, iris thickness was also measured manually as the perpendicular distance from the trabecular meshwork 500 μm anteriorly to the scleral spur (IT500).Fig. 1


Fourier domain optical coherence tomography to assess the iridocorneal angle and correlation study in a large Caucasian population.

Fernández-Vigo JI, García-Feijóo J, Martínez-de-la-Casa JM, García-Bella J, Arriola-Villalobos P, Fernández-Pérez C, Fernández-Vigo JÁ - BMC Ophthalmol (2016)

Examples of iridocorneal angle measurements made by Fourier Domain optical coherence tomography images. a Trabecular-iris angle (TIA) and (b) Angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur in a normal angle width. c and d TIA, AOD500 and TISA500 measurements in a narrow angle. e and (f) TIA, AOD500 and TISA500 measurements in a wide angle
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4835848&req=5

Fig1: Examples of iridocorneal angle measurements made by Fourier Domain optical coherence tomography images. a Trabecular-iris angle (TIA) and (b) Angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur in a normal angle width. c and d TIA, AOD500 and TISA500 measurements in a narrow angle. e and (f) TIA, AOD500 and TISA500 measurements in a wide angle
Mentions: The measurements made manually on these images were trabecular-iris angle (TIA), angle opening distance 500 μm from the scleral spur (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur [6, 11]. In Fig. 1, it may be seen how these measurements were made. TIA was measured by tracing a line from the angle recess to the Schwalbe’s line and another line on the surface of the iris to the perpendicular point on the Schwalbe’s line. AOD500 was measured as the perpendicular distance from the trabecular meshwork, 500 μm anteriorly from the scleral spur to the anterior iris surface. TISA500 was defined as the area bounded anteriorly by the AOD, posteriorly by a line drawn from the scleral spur perpendicular to the plane of the inner scleral wall to the opposing iris, superiorly by the inner corneoscleral wall, and inferiorly by the iris surface. Using this instrument, iris thickness was also measured manually as the perpendicular distance from the trabecular meshwork 500 μm anteriorly to the scleral spur (IT500).Fig. 1

Bottom Line: Mean angle width measurements were smaller in women (p = 0.02).ACV emerged as the main determinant of TIA (R(2) = 0.705; p < 0.001).In this Caucasian population, strong correlation was detected between FD-OCT anterior angle measurements and ACV, ACD, spherical refractive error and sex, emerging the ACV as the main determinant of TIA.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria San Carlos (IdISSC), c/Profesor Martín Lagos s/n, 28100, Madrid, Spain. jfvigo@hotmail.com.

ABSTRACT

Background: Recently, novel anatomic parameters that can be measured by optical coherence tomography (OCT), have been identified as a more objective and accurate method of defining the iridocorneal angle. The aim of the present study is to measure the iridocorneal angle by Fourier domain (FD) OCT and to identify correlations between angle measurements and subject factors in a large healthy Caucasian population.

Methods: A cross sectional study was performed in 989 left eyes of 989 healthy subjects. The iridocorneal angle measurements: trabecular-iris angle (TIA), angle opening distance (AOD500) and trabecular-iris space area (TISA500) 500 μm from the scleral spur, were made using the FD-OCT RTVue®. Iris thickness was also measured. Correlations were examined between angle measurements and demographic and ocular factors. The main determinants of angle width were identified by multivariate linear regression.

Results: TIA could be measured in 94% of the eyes, and AOD500 and TISA500 in 92%. The means recorded were TIA 35.8 ± 12.2 degrees (range 1.5 to 76.1), AOD500 542.6 ± 285.4 μm (range 15 to 1755), and TISA500 0.195 ± 0.104 mm(2) (range 0.02 to 0.62). The correlation between the temporal and nasal quadrant was R = 0.902 for TIA. The reproducibility of measurements was excellent (intraclass correlation coefficient >0.947). Mean angle width measurements were smaller in women (p = 0.02). Correlation was detected between angle means and anterior chamber volume (ACV; R = 0.848), anterior chamber depth (ACD; R = 0.818), spherical error (R = -0.619) and age (R = -0.487), while no correlation was observed with Intraocular pressure (R = -0.052). ACV emerged as the main determinant of TIA (R(2) = 0.705; p < 0.001).

Conclusions: In this Caucasian population, strong correlation was detected between FD-OCT anterior angle measurements and ACV, ACD, spherical refractive error and sex, emerging the ACV as the main determinant of TIA.

Show MeSH
Related in: MedlinePlus