Macular Degeneration: Gregori G

Lujan BJ, Rosenfeld PJ, Gregori G, Wang F, Knighton RW, Feuer WJ, Puliafito CA. · Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. · Ophthalmic Surg Lasers Imaging. · Pubmed #19320296 No free full text.

Abstract: 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.

Kiss CG, Geitzenauer W, Simader C, Gregori G, Schmidt-Erfurth U. · Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria. · Invest Ophthalmol Vis Sci. · Pubmed #19136707 No free full text.

Abstract: PURPOSE: To evaluate the effects of intravitreal ranibizumab on retinal function and morphology and to identify a correlation between anatomy and function by using spectral domain optical coherence tomography (SDOCT). METHODS: Twenty-three patients affected by neovascular AMD received three injections of ranibizumab in three consecutive months and were monitored by assessment of best corrected visual acuity (BCVA), central retinal sensitivity (CRS) and morphologic changes at the level of the retina and the retinal pigment epithelium (RPE). The morphologic changes, identified by SDOCT segmentation, were mean retinal thickness (MRT), central retinal thickness (CRT), and the pathologic area (lesion area) of the RPE. RESULTS: BCVA increased from a mean 60.1 +/- 8.7 letters at baseline to 67.0 +/- 10.9 at month 3 (P = 0.0003). The CRS at the 0 degrees position increased from 2.8 +/- 3.1 dB at baseline to 4.0 +/- 5.7 at week 1, remaining stable until month 3. Absolute scotoma size decreased continuously from baseline to month 3, in a mean of 5.3 +/- 5.8 to 3.6 +/- 4.0 test point locations. By SDOCT, MRT decreased from 308.6 +/- 25.9 microm at baseline to 268.4 +/- 22.4 microm at month 3 (P = 0.0001). CRT was 365.8 +/- 84.9 and 254.9 +/- 95.1 microm at month 3 (P = 0.0002). The mean RPE lesion area was 6.0 +/- 3.0 mm(2) at baseline, which decreased to 5.0 +/- 3.1 mm(2) at month 3 (P = 0.115). The only significant correlation was identified between the lesion area and CRS. CONCLUSIONS: In ranibizumab therapy, the condition of the RPE lesion may be more relevant for visual function than the usual OCT parameters, retinal thickness.

Tsechpenakis G, Lujan B, Martinez O, Gregori G, Rosenfeld PJ. · Dept. of Electrical and Computer Engineering, University of Miami, USA. · Med Image Comput Comput Assist Interv Int Conf Med Image Comput Comput Assist Interv. · Pubmed #18979829 No free full text.

Abstract: We present a geometric deformable model driven by dynamically updated probability fields. The shape is defined with the signed distance function, and the internal (smoothness) energy consists of a C1 continuity constraint, a shape prior, and a term that forces the zero-level of the shape distance function towards a connected form. The image probability fields are estimated by our collaborative Conditional Random Field (CoCRF), which is updated during the evolution in an active learning manner: it infers class posteriors in pixels or regions with feature ambiguities by assessing the joint appearance of neighboring sites and using the classification confidence. We apply our method to Optical Coherence Tomography fundus images for the segmentation of geographic atrophies in dry age-related macular degeneration of the human eye.

Lujan BJ, Wang F, Gregori G, Rosenfeld PJ, Knighton RW, Puliafito CA, Danis RP, Hubbard LD, Chang RT, Budenz DL, Seider MI, Knight O. · Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. · Ophthalmic Surg Lasers Imaging. · Pubmed #18777875 No free full text.

Abstract: BACKGROUND AND OBJECTIVE: Measurements performed on fundus images using current software are not accurate. Accurate measurements can be obtained only by calibrating a fundus camera using measurements between fixed retinal landmarks, such as the dimensions of the optic nerve, or by relying on a calibrated model eye provided by a reading center. However, calibrated spectral domain OCT (SD-OCT) could offer a convenient alternative method for the calibration of any fundus image. PATIENTS AND METHODS: The ability to measure exact distances on SD-OCT fundus images was tested by measuring the distance between the center of the fovea and the optic nerve. Calibrated SD-OCT scans measuring 6 X 6 X 2 mm centered on the fovea and the optic nerve were analyzed in 50 healthy right eyes. The foveal center was identified using cross-sectional SD-OCT images, and the center of the optic nerve was identified manually. The SD-OCT scans were registered to each other, and the distances between the center of the optic nerve and fovea were calculated. The overlay of these SD-OCT fundus images on photographic fundus images was performed. RESULTS: Any image of the fundus could be calibrated by overlaying the SD-OCT fundus image, and the measurements were consistent with previously defined calibration methods. The mean distance between the center of the fovea and the center of the optic nerve was 4.32 +/-0.32 mm. The line from the center of the optic nerve to the foveal center had a mean declination of 7.67 +/- 3.88 degrees. Mean horizontal displacement and vertical displacement were 4.27 +/- 0.29 mm and 0.58 +/- 0.29 mm, respectively. CONCLUSIONS: The overlay of the SD-OCT fundus image provides a convenient method for calibrating any image of the fundus. This approach should provide a uniform standard when comparing images from different devices and from different reading centers.

Gregori NZ, Rosenfeld PJ, Puliafito CA, Flynn HW, Lee JE, Mavrofrides EC, Smiddy WE, Murray TG, Berrocal AM, Scott IU, Gregori G. · Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida 33136, USA. · Retina. · Pubmed #17031288 No free full text.

Abstract: PURPOSE: To evaluate the safety and efficacy of intravitreal triamcinolone acetonide (IVTA) as treatment for macular edema associated with central retinal vein occlusion (CRVO). METHODS: A retrospective review was performed of data for 40 consecutive patients (40 eyes) with CRVO and macular edema treated with IVTA at the Bascom Palmer Eye Institute (Miami, FL). RESULTS: Median duration of symptoms before the first injection was 3 months (range, 1 day to 8 years). Median Snellen visual acuity was 20/400 at baseline (range, 20/60 to light perception; n = 40), 20/300 at 1 month (P = 0.010; n = 37), 20/300 at 3 months (P = 0.007; n = 33), 20/400 at 6 months (P = 0.726; n = 28), and 8/200 at 1 year (P = 0.569; n = 17). Vision improved by > or =3 lines in 21% of eyes at 1 month, 27% at 3 months, 14% at 6 months, and 12% at 1 year. Visual acuity was unchanged from baseline in 71% of eyes at 6 months and 1 year. By 1 year, 50% of eyes received more than one injection (mean = 1.6 injections; range 1-4 injections). Overall, intraocular pressure increased by > or =10 mmHg in 24% of eyes at 1 year. Trabeculectomy was performed on 2 of 12 eyes with preexisting open-angle glaucoma. CONCLUSION: IVTA can substantially improve vision in some patients, but most patients have stable visual acuity compared with baseline at 1 year despite repeated injections.