Brandon J. Lujan

Progression of Geographic Atrophy in Age-Related Macular Degeneration Imaged with Spectral Domain Optical Coherence Tomography

PURPOSE To determine the area and enlargement rate (ER) of geographic atrophy (GA) in patients with age-related macular degeneration (AMD) using the spectral domain optical coherence tomography (SD-OCT) fundus image. DESIGN Prospective, longitudinal, natural history study. PARTICIPANTS Eighty-six eyes of 64 patients with ≥6 months of follow-up. METHODS Patients with GA secondary to AMD were enrolled in this study. Macular scans were performed using the Cirrus SD-OCT (Carl Zeiss Meditec, Dublin, CA). The areas of GA identified on the SD-OCT fundus images were quantified using a digitizing tablet. Reproducibility of these measurements was assessed and the ER of GA was calculated. The usefulness of performing square root transformations of the lesion area measurements was explored. MAIN OUTCOME MEASURES Enlargement rate of GA. RESULTS At baseline, 27% of eyes had a single area of GA. The mean total area at baseline was 4.59 mm(2) (1.8 disc areas [DA]). The mean follow-up time was 1.24 years. Reproducibility, as assessed with the intraclass correlation coefficient (ICC), was excellent on both the original area scale (ICC = 0.995) and the square root scale (ICC = 0.996). Intergrader differences were not an important source of variability in lesion size measurement (ICC = 0.999, 0.997). On average, the ER of GA per year was 1.2 mm(2) (0.47 DA; range, 0.01-3.62 mm(2)/year). The ER correlated with the initial area of GA (r = 0.45; P<0.001), but there were variable growth rates for any given baseline area. When the square root transformation of the lesion area measurements was used as a measure of lesion size, the ER (0.28 mm/yr) was not correlated with baseline size (r = -0.09; P = 0.40). In this cohort of lesions, no correlation was found between ER and length of follow-up. Square root transformation of the data helped to facilitate sample size estimates for controlled clinical trials involving GA. CONCLUSIONS The SD-OCT fundus image can be used to visualize and quantify GA. Advantages of this approach include the convenience and assurance of using a single imaging technique that permits simultaneous visualization of GA along with the loss of photoreceptors and the retinal pigment epithelium that should correlate with the loss of visual function.

Spectral Domain Optical Coherence Tomography Imaging of Drusen in Nonexudative Age-Related Macular Degeneration

PURPOSE To measure drusen area and volume in eyes with nonexudative age-related macular degeneration (AMD) using spectral domain optical coherence tomography imaging (SD-OCT). DESIGN Evaluation of diagnostic technology. PARTICIPANTS One hundred three eyes from 74 patients with drusen. METHODS Patients with drusen secondary to nonexudative AMD were enrolled in this study. Five separate SD-OCT scans, each consisting of 40 000 uniformly spaced A-scans organized as 200 A-scans in each B-scan and 200 horizontal B-scans, were performed on each eye. Each scan covered a retinal area of 6×6 mm centered on the fovea. A novel algorithm was used to quantitatively assess drusen area and volume. Measurements from the entire scans, as well as in regions contained within 3- and 5-mm circles centered on the fovea, were analyzed. Test-retest standard deviations of drusen area and volume measurements were calculated for each eye. MAIN OUTCOME MEASURES Drusen area and volume. RESULTS The algorithm created drusen maps that permitted both qualitative and quantitative assessment of drusen area and volume. Both the qualitative appearance and the quantitative measurements of drusen area and volume were highly reproducible over the 5 different datasets. The intraclass correlation coefficient was >0.99 for both area and volume measurements on the entire dataset as well as the 3- and 5-mm circles. The correlation between lesion size and the test-retest standard deviations can be eliminated by performing a square root transformation of the area measurements and a cube root transformation of the volume measurements. These transformed data allowed for the inclusion of all drusen sizes in the calculation of an estimated single pooled test-retest standard deviation, which will be useful for longitudinal studies of drusen natural history. CONCLUSIONS A novel algorithm for the qualitative and quantitative assessment of drusen imaged using SD-OCT was shown to be highly reproducible. The ability to assess drusen volume reliably represents a new quantitative parameter to measure in AMD and may be useful when assessing disease progression, particularly in trials for treatments of nonexudative AMD.

Spectral domain optical coherence tomographic imaging of geographic atrophy

BACKGROUND AND OBJECTIVE To compare images of geographic atrophy (GA) obtained using spectral domain optical coherence tomography (SD-OCT) with images obtained using fundus autofluorescence (FAF). PATIENTS AND METHODS Five eyes from patients with dry AMD were imaged using SD-OCT and FAF, and the size and shape of the GA were compared. RESULTS GA appears bright on SD-OCT compared with the surrounding areas with an intact retinal pigment epithelium because of increased reflectivity from the underlying choroid. SD-OCT and FAF both identified GA reproducibly, and measurement of the area of GA is comparable between the two methods with a mean difference of 2.7% of the total area. CONCLUSION SD-OCT can identify and quantitate areas of GA. The size and shape of these areas correlate well to the areas of GA seen on autofluorescence images; however, SD-OCT imaging also provides important cross-sectional anatomic information.

Myopic traction maculopathy: Spectral domain optical coherence tomographic imaging and a hypothesized mechanism

A patient with progressive visual loss and macular hole development due to progressive myopic traction maculopathy was studied using spectral domain optical coherence tomography (SD-OCT). A characteristic, deep retinal schisis-like change was clearly demonstrable. Progression to a full-thickness macular hole was documented. Postoperatively, the macular hole was closed, and the visual acuity was restored. SD-OCT imaging allowed better resolution of macular features but requires evaluation of all scan data. The source of progressive inner retinal traction may be the posterior extension of the staphyloma.

Ultra-High Resolution Spectral Domain Optical Coherence Tomography of Traumatic Maculopathy

The authors describe a patient who suffered traumatic maculopathy following blunt trauma to the eye with commotio retinae, subretinal and preretinal hemorrhage, traumatic macular hole, and outer retinal and retinal pigment epithelium disruption. Serial imaging with commercially available and ultra-high resolution spectral domain optical coherence tomography characterized the evolution of the injury.