Correlation in foveal thickness measurements between spectral-domain and time-domain optical coherence tomography in normal individuals.

PURPOSE: To compare a time-domain (Stratus) and a spectral-domain (Spectralis) optical coherence tomography (OCT) device in assessing foveal thickness in healthy subjects. METHODS: In this observational study 40 healthy subjects (40 eyes) underwent Stratus OCT and Spectralis OCT measurements of foveal thickness using three consecutive horizontal and vertical B-scan. Paired samples t-test was used to compare means between Stratus and Spectralis OCT measurements. Coefficient of variation (CoV) was used to compare dispersion in datasets. Pearson's correlation coefficient was used to quantify linear relation between Spectralis and Stratus OCT measurements. To assess agreement between Spectralis and Stratus OCT foveal thickness measurements, the Bland and Altman plots were used. RESULTS: Sample age ranged from 19 to 49 years (mean 33.25, standard deviation (SD) +/-4.22). The Spectralis OCT foveal thickness measurements resulted significantly higher than those obtained with Stratus OCT (227.64+/-11.74 vs 144.36+/-12.25 microm, and 227.63+/-11.43 vs 144.92+/-12.34 microm, for horizontal and vertical foveal thickness, respectively) (P<0.05). Coefficient of variations were 5.16 and 5.02% using Spectralis OCT, and 8.49 and 8.51% using Stratus OCT. Mean Spectralis/Stratus ratio was 1.58 for both horizontal and vertical measurements. A linear relation between the two technologies was found (r(horiz)=0.899 and r(vert)=0.869) (P<0.001). CONCLUSIONS: A good correlation between Stratus and Spectralis OCT foveal measurements was found, independently of retinal thickness. This preliminary study suggests the existence of a conversion factor between Stratus and Spectralis OCT when measuring healthy foveal thickness.

Custom measurement of retinal nerve fiber layer thickness using STRATUS OCT in normal eyes.

PURPOSE: To evaluate variability of retinal nerve fiber layer (RNFL) thickness measurements in normal eyes and their correlation with optic disc diameter by using two different scan options of the ultimate commercial optical coherence tomography (OCT) unit (STRATUS OCT, Carl Zeiss Meditec, Inc., Dublin, CA). METHODS: In this observational case series and instrument validation study 30 eyes of 30 normal subjects were enrolled. Each eye underwent optic disc vertical diameter measurement by means of both stereoscopic photography and planimetry and OCT; RNFL thickness measurements were performed using OCT. Three repetitions of two series of scans were performed. Each eye was scanned at two different options (RNFL thickness 3.4 and Nerve Head Circle). For each option descriptive statistics, analysis of variance, intraclass correlation coefficients (ICCs), and coefficients of variation (COVs) were calculated. To verify the correlation between the two methods of optic disc diameter assessment and to study the influence of optic disc diameter on RNFL measurement using the two different OCT options, Pearson's correlation coefficients were calculated. RESULTS: Optic disc diameter length ranged from 1.47 to 2.04 mm (mean 1.709 mm, SD +/- 0.147) with stereoscopic photographs, and from 1.47 to 2.02 mm (mean 1.703 mm, SD +/- 0.143) with OCT (Pearson correlation coefficient 0.999, p<0.001). Mean RNFL thickness was 89.29 mm (SD +/- 10.80 mm) using the RNFL thickness 3.4 scanning option and 89.88 mm (SD +/- 1.72 mm) using the Nerve Head Circle protocol (Pearson correlation coefficient 0.065, p=0.734). The intersubject variance is higher using the RNFL thickness 3.4 option than using the NHC protocol (sum of square: 1,014,760 vs. 25,741) (p<0.001); the intrasubject variance is very similar in the two groups (2,372 vs 2,360) (p=NS). The ICC is 99.89% when using the RNFL thickness 3.4 option, 95.62% with the NHC protocol (p=NS). COVs were 12.10% and 1.91% by using RNFL thickness 3.4 and Nerve Head Circle option, respectively. Pearson's correlation coefficient was 0.988 (p<0.001) when comparing optic disc diameter and RNFL thickness by using the RNFL thickness 3.4 option and -0.016 (p=0.932) when comparing optic disc diameter and RNFL thickness by using the Nerve Head Circle option. CONCLUSIONS: These results suggest that both scan options give good RNFL thickness measurement reproducibility; the use of the Nerve Head Circle option leads to less interindividual variability and can minimize the effect of differences in optic disc diameter on RNFL thickness measurements in normal subjects.

Optical coherence tomography and fundus microperimetry imaging of spontaneous closure of traumatic macular hole: a case report.

PURPOSE: To report a case of spontaneous closure of traumatic macular hole in a young patient followed using optical coherence tomography (OCT) and fundus microperimetry. METHODS/RESULTS: In the right eye of a 10-year-old child, a traumatic macular hole was observed to spontaneously resolve 18 weeks after blunt trauma. Initially, visual acuity in the right eye was 20/200 and OCT examination showed a 200 microm-diameter full-thickness macular hole with perifoveal edema. Fundus microperimetry examination showed an evident decrease in retinal sensitivity within the macular hole and in the upper macular region where an area of commotio retinae was clearly visible. During follow-up OCT demonstrated the appearance of a band of tissue linking the inferior edge of the hole to the foveal retinal pigment epithelium and at the bottom of the hole the presence of hyperreflective (glial) material. Eighteen weeks after trauma right eye visual acuity had improved to 20/25, OCT examination showed a restored foveal depression, and fundus microperimetry demonstrated an increase in foveal sensitivity. CONCLUSIONS: Both OCT and fundus microperimetry were useful tools for following the favorable course in a case of spontaneous closure of traumatic macular hole in a young patient. During follow-up OCT examinations were able to demonstrate the course of macular hole closure.

Optical coherence tomography imaging of surgical resolution of bilateral vitreomacular traction syndrome related to incomplete posterior vitreoschisis: a case report.

PURPOSE: To report a case of surgical resolution of bilateral vitreomacular traction syndrome related to incomplete posterior vitreoschisis as documented by optical coherence tomography (Stratus OCT, Carl Zeiss Meditec, Dublin, CA). CASE REPORT: In both eyes of a 72-year-old man with bilateral blurred vision, OCT examination disclosed a relevant increase in mean foveal thickness (right eye = 714 microm; left eye = 757 microm) due to a vitreomacular traction syndrome. At the edges of the most highly elevated area of vitreo-macular traction, OCT scans showed a characteristic splitting of the hyperreflective signal in both eyes, usually identified as posterior vitreous cortex. Both eyes underwent vitrectomy with epiretinal membrane peeling. Postoperative OCT examination showed vitreomacular traction resolution in both eyes with an evident decrease in mean foveal thickness (right eye = 364 microm; left eye = 335 microm). Right visual acuity improved from 20/200 to 20/50; left visual acuity changed from 20/150 to 20/40. CONCLUSIONS: OCT was a useful tool in identifying an unusual case of bilateral vitreomacular traction syndrome linked to incomplete posterior vitreoschisis and following a favorable course after surgical management.

Optical coherence tomography and retinal thickness analyzer features of spontaneous resolution of vitreomacular traction syndrome: a case report.

PURPOSE: To report optical coherence tomography (OCT) and retinal thickness analyzer (RTA) findings in a case of spontaneous resolution of vitreomacular traction syndrome. METHODS: Qualitative and quantitative analysis of the macular region was performed with OCT and RTA. RESULTS: In the left eye of a 34-year-old woman with blurred vision, OCT and RTA examination showed a discrete linear signal anterior to the retina with attachment at the macula and secondary cystoid macular changes. OCT and RTA examination showed an increase in macular thickness (350 microm). Six months later the patient showed a spontaneous complete recovery of visual acuity. Vitreomacular traction and cystoid changes were no longer detectable at OCT and RTA examination; retinal thickness was normal (205 microm) and a posterior vitreous detachment was visible. CONCLUSIONS: Both OCT and RTA were useful tools for making the diagnosis of vitreomacular traction syndrome and demonstrating the effect of spontaneous vitreomacular traction release with resolution of cystoid macular changes.