Mahsa A. Sohrab

Image registration and multimodal imaging of reticular pseudodrusen

PURPOSE To characterize reticular pseudodrusen (RPD) by using a point-to-point comparison of the reticular pattern on infrared reflectance (IR), autofluorescence (AF), and red-free (RF) images registered with en face sections of the choroid from spectral domain optical coherence tomography (SD-OCT) scans. METHODS A cross-sectional, retrospective study of all patients with the diagnosis of AMD who presented to the Doheny Retina Institute between December 2007 and November 2009 was conducted to identify patients with RPD. IR, AF, and RF images were obtained using confocal scanning laser ophthalmoscopy and were manually registered to OCT choroidal sections to study the location of RPD. The main outcome measured was point-to-point localization of RPD across multiple imaging modalities. RESULTS Of the 153 patients with AMD, 51 had RPD. In all 51 patients (97 eyes), RPD appeared as areas of hypoautofluorescence and hyporeflectance on AF and IR imaging, respectively, and as hyporeflective interlacing networks on RF. Reticular lesions on AF, IR, and RF images consistently colocalized with stromal regions between large choroidal vessels on registered en face choroidal sections. In contrast, outer retinal changes and subretinal deposits tended to localize immediately adjacent to the RPD. CONCLUSIONS Point-to-point correlation of registered IR, AF, and RF images consistently localizes the reticular pattern to the intervascular choroidal stroma on en face OCT sections. In contrast, subretinal deposits and disturbances of the inner outer segment on OCT did not colocalize with the RPD, and may represent secondary mechanical or biologic disturbances in the overlying RPE and outer retina.

A Pilot Study of Morphometric Analysis of Choroidal Vasculature In Vivo, Using En Face Optical Coherence Tomography

Purpose To study the ability of volumetric spectral domain optical coherence tomography (SD-OCT) to perform quantitative measurement of the choroidal vasculature in vivo. Methods Choroidal vascular density and vessel size were quantified using en face choroidal scans from various depths below the retinal pigment epithelium (RPE) in 58 eyes of 58 patients with either epiretinal membranes (ERM), early age-related macular degeneration (AMD), or reticular pseudo-drusen (RPD). For each patient, we used the macular volume scan (6×6 mm cube) for vessel quantification, while high-definition (HD) cross-section raster scans were used to qualitatively assess vascularity of the choroidal sub-layers, and measure choroidal thickness. Results Of the 58 patients, more were female (66% versus 34% male), of whom 14 (24%) had ERM, 11 (19%) early AMD, and 33 (57%) RPD. Compared to intact choriocapillaris in all ERM (100%), none of the RPD and only 5/11 (45%) early AMD eyes had visible choriocapillaris on either cross section or C-scans (p-value<0.001). When comparing select regions from the most superficial C-scans, early AMD group had lowest vascular density and RPD had highest (p-value 0.04). Qualitative evaluation of C-scans from all three groups revealed a more granular appearance of the choriocapillaris in ERM versus increased stroma and larger vessels in the RPD eyes. Conclusions SD-OCT can be used to qualitatively and quantitatively assess choroidal vascularity in vivo. Our findings correlate to previously reported histopathologic studies. Lack of choriocapillaris on HD cross-sections or C-scans in all RPD and about half of early AMD eyes suggests earlier choroidal involvement in AMD and specifically, RPD.

Imaging characteristics of dry age-related macular degeneration.

Purpose: To review the current literature regarding the imaging characteristics of dry age-related macular degeneration (AMD) lesions, with a special focus on drusen and geographic atrophy imaging. We also explore the role of novel approach of hyperspectral imaging in AMD. Methods: Review of current literature as well as findings in a small group of patients imaged with hyperspectral imaging. Results: The use of optical coherence tomography, and especially fourier-domain devices, has enhanced our ability to classify various lesions of dry AMD. The increasing role of autofluorescence in characterization and prognostication in geographic atrophy is reviewed. The advances made in automated detection and multimodal imaging are highlighted, with their potential to revolutionize this area of research. Conclusions: Recent advances in retinal imaging have improved our understanding of the characteristics and prognostication of dry AMD, with an increasing role for multimodal imaging and image correlations. The potential future role of hyperspectral imaging in dry AMD is also presented herein.

Re: "Drug-induced Graves disease from CTLA-4 receptor suppression".

Here, we took notice of the “heat generation” of this apparatus for hemostasis from the cortical bone. In usual sessions, the console is set at 70% to 90% in power and 15 ml/ minute in irrigation for safe and efficient bone curettage. With the integrated cooling function enhanced, the heat generation is reduced, leading to a lower hemostatic effect. To generate heat appropriately, we set the irrigation at 3 ml/minute and set the power at 30% to 40% to prevent excess bone curettage (Fig. A, B, and see Video, Supplemental Digital Content 1, available at http://links.lww.com/IOP/A65, which demonstrates hemostasis using the SONOPET UST-2001 during a lateral orbital decompression surgery). A dull tip is better than a fine one for this purpose. This procedure settles a troublesome problem of “hemorrhage from the cortical bone” and allows the oculoplastic surgeon to not worry about the postsurgical orbital hematoma.

Comparison of Fasanella-Servat and Small-Incision Techniques for Involutional Ptosis Repair.

Purpose: To compare the results of the classic Fasanella-Servat internal approach to the newer, small-incision external approach in the repair of involutional ptosis. Methods: Retrospective review identified 93 patients (104 surgical procedures) at Northwestern Ophthalmology from June 2005 until October 2011 who underwent either the Fasanella-Servat or the small-incision approaches for involutional ptosis repair. Change in vertical palpebral fissure measurement, change in marginal reflex distance 1 (MRD1) measurement, patient satisfaction, surgical complications, operating time, and postoperative pain were compared between groups. Results: Of the 93 patients, most were female with an average age of 69 years. Of the procedures, 48% were small incision and 52% were Fasanella-Servat approaches. Average postoperative follow up was 34.0 days. Vertical palpebral fissure height increased an average of 3.36 mm (±1.15) in the Fasanella-Servat group and 2.74 mm (±1.18) in the small-incision group (p = 0.003). Preoperative vertical palpebral fissure height was lower in the Fasanella-Servat group, but postoperative vertical palpebral fissure height was similar between the 2 groups (p=0.3). MRD1 increased an average of 3.42 mm (±0.86) in the Fasanella-Servat group and 2.68 mm (±0.93) in the small-incision group (p < 0.01). Preoperative MRD1 was lower in the Fasanella-Servat group, but postoperative MRD1 was similar between the 2 groups (p = 0.15). Average operating time was 53 minutes (±16) in the small-incision group and 27 minutes (±6) in the Fasanella-Servat group (p < 0.01). There were no surgical complications in either group with equivalent patient satisfaction between the 2 groups. More patients reported postoperative pain in the Fasanella-Servat group (p < 0.0001). Conclusions: Both the Fasanella-Servat and small-incision approaches lead to good surgical outcomes with equivalent patient satisfaction, although the Fasanella-Servat approach provides a shorter average operating time with satisfactory postoperative MRD1.

A validated phenotyping algorithm for genetic association studies in age-related macular degeneration

Age-related macular degeneration (AMD), a multifactorial, neurodegenerative disease, is a leading cause of vision loss. With the rapid advancement of DNA sequencing technologies, many AMD-associated genetic polymorphisms have been identified. Currently, the most time consuming steps of these studies are patient recruitment and phenotyping. In this study, we describe the development of an automated algorithm to identify neovascular (wet) AMD, non-neovascular (dry) AMD and control subjects using electronic medical record (EMR)-based criteria. Positive predictive value (91.7%) and negative predictive value (97.5%) were calculated using expert chart review as the gold standard to assess algorithm performance. We applied the algorithm to an EMR-linked DNA bio-repository to study previously identified AMD-associated single nucleotide polymorphisms (SNPs), using case/control status determined by the algorithm. Risk alleles of three SNPs, rs1061170 (CFH), rs1410996 (CFH), and rs10490924 (ARMS2) were found to be significantly associated with the AMD case/control status as defined by the algorithm. With the rapid growth of EMR-linked DNA biorepositories, patient selection algorithms can greatly increase the efficiency of genetic association study. We have found that stepwise validation of such an algorithm can result in reliable cohort selection and, when coupled within an EMR-linked DNA biorepository, replicates previously published AMD-associated SNPs.

Retinal manifestations of renal and connective tissue diseases.

A broad range of renal and connective tissue diseases with both hereditary and nonhereditary etiologies have been associated with retinal manifestations. As ocular examination techniques including newer imaging modalities evolve, increasing forms of systemic diseaseassociated retinal dysfunction are being recognized. With the availability of improving and varied treatment modalities, the identification and monitoring of these retinal abnormalities has become more important. In this review, we discuss the various retinal manifestations of systemic renal and connective tissue diseases, also including available diagnostic and management recommendations.