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Vermeer K.A.,Rotterdam Ophthalmic Institute | Mo J.,VU University Amsterdam | Weda J.J.A.,VU University Amsterdam | Lemij H.G.,Glaucoma Service | And 2 more authors.
Biomedical Optics Express | Year: 2014

We present a method, based on a single scattering model, to calculate the attenuation coefficient of each pixel in optical coherence tomography (OCT) depth profiles. Numerical simulations were used to determine the model's response to different depths and attenuation coefficients. Experiments were performed on uniform and layered phantoms with varying attenuation coefficients. They were measured by a 1300 nm OCT system and their attenuation coefficients were evaluated by our proposed method and by fitting the OCT slope as the gold standard. Both methods showed largely consistent results for the uniform phantoms. On the layered phantom, only our proposed method accurately estimated the attenuation coefficients. For all phantoms, the proposed method largely reduced the variability of the estimated attenuation coefficients. The method was illustrated on an in-vivo retinal OCT scan, effectively removing common imaging artifacts such as shadowing. By providing localized, per-pixel attenuation coefficients, this method enables tissue characterization based on attenuation coefficient estimates from OCT data. © 2013 Optical Society of America.


Mantravadi A.V.,Glaucoma Service | Vadhar N.,Thomas Jefferson University
Primary Care - Clinics in Office Practice | Year: 2015

Glaucoma is a multifactorial degenerative optic neuropathy that can progress at variable rates and afflict all age groups. It is the second leading cause of blindness worldwide. The disease is commonly divided into 2 major subtypes, open angle and angle closure. Diagnosis of glaucoma is made by a combination of identifying characteristic changes of the optic nerve, functional testing such as visual fields, and structural imaging of the optic nerve. Management is aimed at reducing intraocular pressure (IOP). Patients with known risk factors should be referred to an ophthalmologist for complete evaluation. © 2015 Elsevier Inc.


Ou Y.,Duke University | Ou Y.,University of California at San Francisco | Goldberg I.,University of Sydney | Migdal C.,Glaucoma Service | Lee P.P.,Duke University
Ophthalmology | Year: 2011

Purpose: To appraise primary open-angle glaucoma (POAG) practice guidelines critically and to compare these guidelines' major recommendations. Design: Evaluation of clinical practice guidelines and their development process. Participants: Glaucoma fellowship-trained ophthalmologists. Methods: The POAG clinical practice guidelines published by the American Academy of Ophthalmology (AAO), European Glaucoma Society (EGS), and South East Asia Glaucoma Interest Group (SEAGIG) were evaluated by independent reviewers using the Appraisal of Guidelines for Research and Evaluation (AGREE) instrument. Main Outcome Measures: Domain scores using the AGREE instrument. Results: Critical appraisal using the AGREE instrument demonstrated that the AAO guidelines scored favorably (>60%) in the domains of scope and purpose, rigor of development, and clarity and presentation, while scoring unfavorably (<60%) in the domains of stakeholder involvement, applicability, and editorial independence. The Terminology and Guidelines for Glaucoma and the Asia Pacific Glaucoma Guidelines respectively developed by EGS and SEAGIG scored favorably in the domains of scope and purpose and clarity and presentation, but scored unfavorably in the domains of stakeholder involvement, applicability, and editorial independence. The major recommendations regarding diagnosis and management of POAG were similar among the 3 guidelines, although the level of detail varied considerably. Conclusions: Although the clinical practice guidelines from the AAO, SEAGIG, and EGS have contributed to developing evidence-based guidelines for glaucoma management, there is variability in the quality of the guideline development process and how it is reported as evaluated by a standardized instrument. The adoption of common standards in developing clinical practice guidelines in ophthalmology should improve their consistency and quality. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. © 2011 American Academy of Ophthalmology.


van der Schoot J.,Rotterdam Ophthalmic Institute | Vermeer K.A.,Rotterdam Ophthalmic Institute | de Boer J.F.,Rotterdam Ophthalmic Institute | de Boer J.F.,VU University Amsterdam | Lemij H.G.,Glaucoma Service
Investigative Ophthalmology and Visual Science | Year: 2012

PURPOSE. To demonstrate the effect of glaucoma on the optical attenuation coefficient of the retinal nerve fiber layer (RNFL) in Spectral Domain Optical Coherence Tomography (SD-OCT) images. METHODS. We analyzed images of the peripapillary areas in 10 healthy and 30 glaucomatous eyes (mild, moderate, and advanced glaucoma, 10 eyes each), scanned with the Spectralis OCT (Heidelberg Engineering GmbH, Dossenheim, Germany). To calculate the RNFL attenuation coefficient (μ att), determined by the scattering properties of the RNFL, we used a model that normalized the reflectivity of the RNFL by the retinal pigment epithelium. The analysis was performed at four preset locations at 1.3 and 1.7 mm from the center of the optic nerve head (ONH) (i.e., temporally, superiorly, nasally, and inferiorly) and on averages per eye. To assess the structure-function relationship, we correlated the μ att to the mean deviation (MD) in standard automated perimetry. RESULTS. The μ att of the RNFL decreased up to 40% with increasing disease severity, on average as well as in each location around the ONH (Jonckheere-Terpstra test, P < 0.019 in all tests). The μ att of the RNFL depended significantly on the location around the ONH in all eyes (Kruskal-Wallis test, P < 0.014) and was lowest nasally from the ONH. The μ att correlated significantly with the MD in SAP (R 2 1/4 0.337). CONCLUSIONS. The measurements clearly demonstrated that the μ att of the RNFL decreased with increasing disease severity. The RNFL attenuation coefficient may serve as a new method to quantify glaucoma in SD-OCT images. © 2012 The Association for Research in Vision and Ophthalmology, Inc.


Salim S.,Glaucoma Service
Current Opinion in Ophthalmology | Year: 2014

PURPOSE OF REVIEW: Glaucoma management during pregnancy generates numerous therapeutic challenges and potential risks for both the patient and the fetus. Data are limited on this topic given the lack of large, prospective, and randomized clinical trials because of ethical and legal constraints in this patient population. Therefore, many ophthalmologists remain unsure about treating glaucoma during pregnancy and lactation. This review focuses on the importance of preconception planning, the natural course of intraocular pressure during pregnancy, and a discussion of various therapeutic modalities during pregnancy and lactation. RECENT FINDINGS: The risks of glaucoma medications during pregnancy are not well established for the human fetus or infant and are often inferred from animal studies. Some guidelines have been provided by the US Food and Drug Administration (FDA) about medication safety during pregnancy. Currently, brimonidine is classified as a category B medication with presumed safety based on animal studies. Other glaucoma medications (beta blockers, carbonic anhydrase inhibitors, parasympathomimetics, and prostaglandin analogues) are classified as category C medications with uncertain safety from the lack of human studies and reported adverse effects in animal studies. SUMMARY: The treatment of glaucoma during pregnancy and lactation requires careful consideration and understanding of disease status, stage of pregnancy, FDA classification and guidelines, and potential benefits and limitations of various therapeutic modalities. A multidisciplinary team approach is necessary to appropriately balance the risks and benefits of any intervention and to individualize treatment to achieve the best outcomes for both mother and fetus. © 2014 Wolters Kluwer Health.

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