Spectral Domain Optical Coherence Tomography Based Alterations in Macular Thickness and Inner Segment Ellipsoidare Associated with Severity of Diabetic Retinopathy

Introduction: Peripapillary retinal nerve fiber layer (RNFL) thinning occurs in the diabetic patients earlier than the detectable diabetic retinopathy. We conducted this study to evaluate the RNFL thickness and macular thickness in elderly diabetic patients using optical coherence tomography in comparison to healthy controls. Material and methods: One fifty study participants were divided in 3 groups (50 each): normal subjects, patients with diabetes with no detectable diabetic retinopathy (NDR) and patients with diabetic retinopathy (DR) of differing severity. The RNFL thickness and macular thickness was measured using spectral-domain optical coherence tomography (SD OCT). Results: The RNFL thickness around the optic disc differed significantly among all the 3 groups and tended to become thinner as the patient develops DR in elderly subjects. The mean, superior-temporal and upper nasal peripapillary RNFL thickness differed among all the 3 groups. We observed that, mean superior, temporal, inferior and nasal RNFL tended to be thinner as the patient develops DR. Conclusion: The RNFL thickness, macular thickness and ganglion cell complex thinning differed significantly between the healthy group and diabetic group without clinical DR. The RNFL thinning (measured by Spectral-domain OCT) is an early neurodegenerative ocular change in diabetic patients even before onset of diabetic retinopathy.

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Comparison of Macular Thickness Measurements Using Swept-Source and Spectral-Domain Optical Coherence Tomography in Healthy and Diabetic Subjects

10.1101/2020.11.22.20236307 ◽

2020 ◽

Author(s):

Kun Xiong ◽

Wei Wang ◽

Xia Gong ◽

Wangting Li ◽

Yuting Li ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Diabetic Retinopathy ◽

Macular Thickness ◽

Spectral Domain ◽

Optical Coherence ◽

Swept Source ◽

Macular Volume ◽

Conversion Equation ◽

Thickness Measurements ◽

Sd Oct

AbstractPurposeTo compare macular thicknesses measured using swept-source optical coherence tomography (SS-OCT) and spectral domain OCT (SD-OCT) in normal subjects, diabetics with diabetic retinopathy (DR) and diabetics without DR (NDR).MethodsWe analysed 510 normal eyes, 741 NDR eyes and 209 DR eyes. Mean macular thicknesses in Early Treatment Diabetic Retinopathy Study (ETDRS) subfields, central point thicknesses (CPT), and macular volume were measured by SS-OCT and SD-OCT. We assessed agreement between SS-OCT and SD-OCT measurements by intraclass correlation coefficients (ICC) and Bland-Altman plots, and established a conversion equation relating central subfield (CSF), CPT and macular volume between the two devices.ResultsMacular thickness measurements by SS-OCT were significantly thinner than those by SD-OCT. The mean CSF thickness in normal eyes measured by SD-OCT and SS-OCT were 226.6 ± 19.1 μm (male 236.1 ± 19.1 μm vs female 223.0 ± 17.9 μm, p < 0.0001) and 258.4 ± 19.8 μm. In all three groups, the agreement between SS-OCT and SD-OCT was excellent (all ICC ≥ 0.866). For CSF the conversion equation SD-OCT = 31.95 + 0.999 × SS-OCT was derived. Using the equation, with 99.6% and 97.6% of the predicted values for CSF fell within 10% of the actual measurements in DR and NDR eyes, respectively.ConclusionWe propose SS-OCT CSF thicknesses of 275 μm for males and 260 μm for females as the minimum criteria for macular edema in Chinese eyes. And SS-OCT measurements were significantly thinner than those of SD-OCT, we derived an equation to convert SS-OCT measurements to SD-OCT equivalents.

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