Comparison of genetic mapping of the PTC/obesity connection on chromosome 7 in twins. (Grzybowski) The objectives are: 1) Find patients with IIH; 2) Acquire patient family histories for at least 12 families out to 4 generations; 3) Acquire blood samples. We want to investigate the mechanism by which IIH occurs. This study aims to identify the factors (genes) that are involved in IIH in our efforts toward better treatments for the disease. To date 8 families have been identified for this study. To date 10 families have been identified and protocols are being written to collect blood samples to be banked and analyzed.

Corneal Biomechanical and Hydration Model before and after Refractive Surgery. (Grzybowski and Roberts) A combination of topography, wavefront, reflectivity, and autorefraction data will be used to create a model of corneal biomechanical response to refractive surgery that includes the critical factor of corneal hydration. Subjects who have undergone LASIK surgery demonstrate an exaggerated swelling response to induced corneal edema. Using the Heidelberg OCT reflectance a correlation between percent swelling and percent change in reflectance for post-LASIK corneas in the peripheral region may be related to the lack of tension in the peripheral lamellar segments as a result of the surgical procedure, which results in a decreased scatter with increased swelling. A manuscript is in review with the Journal of Refractive Surgery; multiple other manuscripts are in preparation.

Corneal Stem Cell Culturing (Mauger and Gryzbowski) Corneal stem cell deficiency can result from congenital defects, injury, infections, contact lens wear, and surgery. Cadeveric transplantation is associated with a high rate of failure and the need for systemic immunosuppression. It is a therapeutic challenge and leads to significant visual loss, pain, and blindness, We propose to create a laboratory model to grow corneal epithelium from a patient with stem cell dysfunction for eventual replacement over their own cornea. Oral gingival cells and conjunctival cells will also be evaluated.

Corneal Stroma Collagen Fiber Density as Measured with the Confocal Microscopy (Mauger and Roberts) The response of the cornea to surgery, injury, or disease is partially dependent on the biomechanical properties which are a function of the structure of the cornea. The collagen fiber density will be analyzed from confocal microscope images of normal and abnormal human corneas. These measurements will be correlated with corneal thickness, curvature, refractive error, axial length, intraocular pressure, and corneal hysteresis.

The Influence of Ocular Pulse Amplitude in Glaucoma (Roberts) A new hypothesis is proposed for the influence of the variation in intraocular pressure caused by the heart beat on development and progression of glaucoma. This will be investigated both clinically and in basic modeling studies.

Corneal Biomechanical Properties in Keratoconus (Roberts) A new hypothesis is proposed for biomechanical progression in Keratoconus, in which a confined corneal region has a reduction in elastic modulus. This confined region bulges due to a specific relationship between deformation and applied force. As the bulging occurs, the cornea becomes thinner. This serves as a stress concentration and drives further deformation.

Tissue welding in cataract and corneal wounds (Keates) In cataract surgery today usually three incisions are made(1 main and 2 sideports) which are usually sutured of fluid infiltrated to close and prevent leaks and infections. In corneal transplant surgery multiple wounds are used for endothelial transplant and larger wounds for conventional transplants. This proposal to to use  a combination  of laser and tissue dye to seal the woulds in both cataract and corneal surgery in place of what is used today. Better would closure will decrease the number of dislocations in endothelial transplant. The funds will be used for animal tissue, eyebank tissue, dye preparation and handling . It is hoped that this will quickly move to live surgery.

Effect of Intravitreal Anti-VEGF on Cutaneous Wound Healing (Christoforidis) Anti-VEGF agents have proven themselves useful in the treatment of many ophthalmologic neovascular disorders. The literature has shown that abnormal wound healing is a side effect of systemic anti-VEGF usage. It is known that intravitreal administration leads to peripheral serum levels that are significant, especially in the context of neovascular disease. Despite this information, little research has been done to gauge whether intravitreal anti-VEGF administration has an appreciable clinical effect in the periphery. Many of the patients that we see in retina clinic that require intravitreal anti-VEGF therapy have had recent surgical interventions. However, we don't know the effect that this therapy has on delaying or preventing wound closure. In the current study, it is intended to use a rabbit model to determine if intravitreal anti-VEGF therapy inhibits peripheral wound healing.

X-Ray fiber diffraction analysis of the optic nerve and surrounding sclera (Lewis)- Porcine optic nerve will be used to develop fibril scattering techniques at the APL synchrotron (Chicago). Human optic nerve region ultrastructure will then be mapped to correlate fibril organization and structure with changes in the optic nerve likely associated with age, vision loss and myopia. Preliminary data have been collected.

Clinical Corneal Oxygen Uptake Analysis (Lewis, Mauger) This project will test the feasibility of corneal surface oxygen uptake measurements using the novel application of a handheld portable microsensor probe. IRB approval was granted and preliminary data have been collected, however a new probe is required to continue the project.

Corneal Biomechanical Analysis in Clinical Pediatric Population (Lewis, Roberts)- With Children's Hospital, IRB approval has been granted to collect and characterize the corneal response to air-puff applanation as a function of age, intraocular pressure, corneal curvature, axial length and refraction in a pediatric population. The technique for routine analysis in children will be developed. A database of properties will be generated. Future studies may use these data to identify disease early.

1. Grzybowski, D.M., Herderick, E.E., Kapoor, K.G., Holman, DW, Katz, SE. "Human arachnoid granulations Part I: A technique for quantifying area and distribution on the superior surface of the cerebral cortex." Cerebrospinal Fluid Research July 2007, 4:6. 2.Roberts C.J., Rivera, B.K., D.M. Grzybowski, A. Mahmoud, and P.A. Weber: "Effect of Low Fluence Laser Irradiation on Hydraulic Conductivity of Perfused TM Cell Monolayers," Current Eye Research. 2007 Jul;32(7):625-38.

3. Mahmoud AM, Roberts CJ, Lembach RG, Twa MD, Herderick EE, McMahon TT, and the CLEK Study Group: "CLMI: The Cone Location and Magnitude Index." Cornea 2008; 27(4):480-487.

4. Glimcher, SA, Holman, DW, Lubow, M, and Grzybowski, DM. "Ex vivo model of CSF outflow through Human Arachnoid Granulations: Mechanisms of fluid outflow and implications for disorders of CSF homeostasis." In press, IOVS, May 2008.

5. Baker, KR, Zimmerman, A, Grzybowski, DM, McLaughlin, WR, Katz, SE, Pfriem, DB, Good, GW. "Optical Quality and Impact Resistance Comparisons of Two Football Helmet Faceshields." In Press Journal of Optometry.

6. Glass DH, Roberts CJ, Litsky AS, Weber PA. A Viscoelastic Biomechanical Model of the Cornea describing the Effect of Viscosity and Elasticity on Hysteresis. IOVS, In press.

Grzybowski DM, Twa MD, Mahmoud AM, Morin CE, Ou J, Yeates S, Castellano CJ, Roberts CJ. "Time-course of the biomechanical and corneal swelling response to nitrogen in normal and post LASIK eyes." ARVO 2008. Poster 657/D916.

Morin CE, Grzybowski DM, Roberts CJ. "Reflectivity and pachymetry response to corneal swelling in normal and post LASIK eyes with the SL-OCT." ARVO 2008. Poster 658/D917.

Mahmoud AM, Twa MD, Pepose JS, Qazi MA, Kollbaum P, Roberts CJ. "Influence of region of interest and area analyzed on the calculation of the highest elevation above the posterior best fit sphere." ARVO 2008. Poster 1019/D875.

Roberts CJ, Peterson JD, Mahmoud AM, Weber PA. "The influence of age on anatomic and biomechanical ocular parameters in "stiffer" and "softer" normal healthy eyes." ARVO 2008. 2045.

Grzybowski, DM, Allred,CW, Donahue,JE, Glimcher, SA, Johanson,CE, and Stopa, EG. “Amyloid-β and Glaucoma: The Retinal Ganglion Cell - Neurotoxic Connection,” North American Neuroophthalmology Society Annual Meeting, March 11, 2008, Orlando, Florida.

W.R. Bryan Diabetic Eye Disease Grant Program: New Proposal

Deborah Grzybowski, Ph.D.

Retinal capillary perfusion is well demonstrated with fluorescein retinal angiography. Cardiac capillary perfusion is poorly recognized, but manifested by subendocardial hypoperfusion. Renal capillary disease is recognized histopathologically by needle biopsy, but otherwise not easily demonstrable. These three critical areas are believed to be involved by the vascular disease of diabetes mellitus, as well as in lupus, hypertension, and other vasculopathies.

In the future, we plan to show the relevance of accurately visualized retinal perfusion abnormalities via fluorescein neuroretinal angiography. Additional capillary perfusion defects, in those cases where such information will be available, will be shown by cardiac magnetic resonance imaging (CMR) and by appropriate clinical evaluation of renal function. We also predict that a subset of DM patients has abnormal retinal angiography, but normal MPRI and renal evaluation, who can be identified for subsequent longitudinal studies to assess the predictive value of retinal angiography for myocardial and renal disease.

For this first phase of the project, we plan to show a correlation in retinal microvascular perfusion defects with subendocardial and renal perfusion defects using histology and image processing in normal and diabetic autopsy tissues.

We hypothesize that retinal capillary perfusion abnormalities in diabetes mellitus (DM) will predict equivalent vascular disease manifested by diffuse subendocardial ischemia (in contradistinction to the epicardial ischemia of coronary artery disease) and by renal impairment with vasculopathies involving capillary perfusion and manifested initially by microalbuminuria.

Name of Fellowship Applicant: Leilei Zhang

Name of Fellowship Sponsor or PI: Cynthia Roberts, Ph.D._

Glaucoma is a leading cause of irreversible blindness through the world. World Health Organization statistics, published in 1995, indicate that glaucoma accounts for blindness in 5.1 million persons, or 13.5% of global blindness . In United States, it is a common cause of vision loss threatening over 2.2 million citizens age 40 and older. A recent survey shows that the overall prevalence of Open Angle Glaucoma (OAG) in the US population 40 years and older is estimated to be 1.86% (95% confidence interval, 1.75%-1.96%), with 1.57 million white and 398 000 black persons affected. Owing to the rapidly aging population, the number with OAG will increase by 50% to 3.36 million in 2020. Black subjects had almost 3 times the age-adjusted prevalence of glaucoma than white subjects .

Glaucoma is a group of diseases that can damage the eye’s optic nerve and result in vision loss and blindness . The common denominator of all the glaucomas is a characteristic damage to the optic nerve, which is considered to be due to multiple risk factors, including increased intraocular pressure (IOP). Glaucoma is associated with a progressive loss of vision, which can lead to total, irreversible blindness. However, in most cases, blindness from glaucoma is preventable. The KEY for blindness prevention requires EARLY detection and proper treatment .

Traditional methods for glaucoma diagnosis include testing visual acuity, visual fields, ophthalmoscopy, tonometry and pachymetry. The interpretation of these data depend on the ophthalmologist’s skill including the evaluation of morphological damage to the optical nerve . In the last decade, the laser scanning technique (confocal laser scanning tomography and polarimetry) and optical coherence tomography have become additional, frequently used tools for the morphometry of the optic disc in early glaucoma . The idea of using the optical disc morphometry for glaucoma diagnosis is supported by previous glaucoma studies where the morphologic changes preceded visual field defects as measured by conventional computerized static perimetry . However, the correct interpretation of the morphologic image and the setting of the static test threshold are still problematic . Therefore, more information beyond the morphological data is needed for diagnostic assessment.

Since the death of the retinal ganglion cells is the characteristic finding in optic nerve damage of glaucoma, it is rational that we use retinal tissue health as a direct, early indicator of glaucoma development. Farkas et. al reported various mechanisms for retinal ganglion cell death. Among them, hypoxia (lack of oxygen) is suggested as an important factor contributing to the development of glaucoma. On the other hand, the low oxygen utilization in the local retina area indicates the possible ganglion cell death, and therefore provides the potential for early diagnosis. The spectral images of glaucomatous eyes had showed a higher level of oxygenation at the branched retinal vein occlusion in comparison to other venules elsewhere. These results may indicate lower oxygen utilization in this area due to ganglion cell death .

Despite the importance of retinal tissue oxygenation in glaucoma development, it has not been widely used as a diagnosis criterion by clinicians, partially due to the lack of a quantitative tool. For these reasons, it is very important to develop algorithms and methodologies that can quantify retinal tissue oxygenation in real time and non-invasively. The main goal of the current research is to develop a technique to measure retinal tissue oxygenation.