Emerging trends and hot topics: Presented Thursday, May 11 at the ARVO Annual Meeting

Baltimore, Md. In their own words, First Authors at the 2017 Annual Meeting of the Association for Research in Vision and Ophthalmology explain their findings. Their abstracts were designated as some of the newest and most innovative research presented on Thursday, May 11, 2017.

Anatomy and Pathology/Oncology
#535 - 5639. Inter-Layer Differences in Elastic Properties of Guinea Pig Sclera at the Micrometer Scale with Acoustic Microscopy. 12:45pm.
Nearsightedness is normally associated with excessively long eyes. A change in structural integrity of the eye wall might lead to weakening of the eye wall and underlie this propensity to elongate. Here we use a novel technology (scanning acoustic microscopy) which has the ability to assess stiffness of the eye wall, at a microscopic level, as a first step towards determine the exact changes that occur in the eye wall in nearsighted eyes.

#518 - 5466 - B0623. The Effects of Atropine on the Development of Binocular and Monocular Lens-Induced Myopia in Marmosets. 8:30am.
Nearsighted (myopic) people don't see clearly because their eyes are longer than usual, making them out-of-focus. Eyes develop myopia due in part to genetics, and in part to visual experience. The more myopic someone becomes, the greater the risk of having other eye diseases. This is why it is important to find ways to slow the development of myopia. One of the treatments that eye doctors are using to stop myopic patients from getting worse is an eye drop of a drug called atropine. We don't know exactly how atropine works to do this, and it also has side-effects, so using as little as possible to get the benefit is advisable. In our study we looked at the effects that different doses of atropine had on myopia. We found that when eyes develop large amounts of myopia, atropine was less effective and low dose atropine could not stop it. Atropine at a higher concentration is probably needed for higher myopia that develops quickly.

#518 - 5468 - B0625. Attenuation of myopia progression by aripiprazole is dependent on form deprivation. 8:30am.
Myopia is a sight compromising disease whose prevalence is markedly increasing and can severely detract on life quality. Even though this dysfunctional developmental process is treatable, in some more difficult chronic cases such measures are ineffective and disease complications may develop resulting even in blindness. To improve management of this condition, it was discovered that an association exists between changes in retinal dopamine levels and eye growth as well as emmetropization modulation in primates. Such changes affect these processes through possibly mediating dopamine 2 receptor subtype. To determine whether D2R promotes myopia progression, we compared the effects of a dopamine D2 receptor partial agonist, aripiprazole, on visual development on mice in a normal and vision obstructed environment. Even though this drug did not alter any of the baseline values, it had dose dependent inhibitory effects on myopia progression in a vision obstructed environment. This difference suggests that myopia may somehow alter the response patterns controlled by D2 receptor-linked signaling. Additional studies are warranted to clarify whether or not the responses induced by aripiprazole activation of D2R linked signaling are dependent on form deprivation.

#518 - 5469 - B0626. Effect of Topical Latanoprost on Myopia Progression in Guinea Pigs. 8:30am.
Myopia (near-sightedness) results from excessive eye enlargement. It has become a significant public health concern, due in part to its rising prevalence world-wide, now at epidemic levels in some parts of the world. The eye is like a balloon, with the pressure inside the eye, known as intraocular pressure (IOP), exerting a stretching influence on the outer (scleral) wall of the eye. Remodeling of the latter wall, as in myopia, makes it more susceptible to stretching and so eyes will enlarge more. Following this logic, we tested the idea that eye enlargement and thus myopia progression can be reduced using IOP-lowering drugs. As our myopia model, we used guinea pigs wearing white plastic covers (diffusers) over one eye, which is known to induce excessive eye enlargement. The same eyes of half of the animals were treated with IOP-lowering drops and the others, with artificial tears. All animals underwent weekly eye examinations to measure their myopia, eye length and IOP. The IOP-lowering drops reduced eye pressure, as expected, and also inhibited "myopic eye growth" in our guinea pigs over the course of the 3-month study period. These results open the exciting possibility of using already approved IOP-lowering drugs for myopia control.

#519 - 5480 - B0637. Novel Myopia Genes and Pathways identified from Syndromic Forms of Myopia. 8:30am.
Myopia (short-sightedness) is a condition that has doubled in frequency in less than 30 years and, alarmingly, is still increasing. It is expected to affect 2.5 billion people by 2020 and 5 billion by 2050. Remarkably, we still don't why this is happening. Our study is an innovative step towards answering that question. We examined 130 rare genetic diseases that cause a range of problems including myopia, and compared that to genetic data that has been collected from normal subjects who have myopia. This revealed that 21 of the genes that cause rare diseases seem to contribute to "˜normal' myopia. We then looked at what the genes that cause these rare genetic diseases actually did in the body and found five new biochemical pathways that can lead to myopia. Together these new insights may help to solve the mystery of why the world is becoming myopic.

#519 - 5495 - B0652. Flexible optical waveguides for uniform periscleral crosslinking. 8:30am.
Myopia, or short-sightedness, affecting billions of people worldwide, is a leading cause of blindness and increases the risk of serious disorders such as retinal detachment, glaucoma and cataract. Weakening of the sclera, the white protective layer of the eye, is thought to underlie the accelerated axial eye growth that occurs in myopia progression. A potentially promising strategy for inhibiting axial growth is by strengthening the sclera through photochemical collagen crosslinking, a technique that is already used to strengthen weakened corneas in the clinic. However, delivering light to the sclera is technically challenging due to tight anatomical constraints, as well as the need to deliver light uniformly around the eye. To address these challenges, we have developed flexible, polymer-based waveguides optimized for light delivery to sclera. Using blue light and a riboflavin photosensitizer, we demonstrate efficient and uniform crosslinking of sclera around the equator of porcine eyeballs, resulting in a near-two fold increase in stiffness. We anticipate our method of sclera crosslinking will be useful as a preventive technique to control myopia progression in at-risk children and young patients with high myopia.

#518 - 5464 - B0621. Subconjunctival injection of gap junction antagonist (18-β-glycyrrhetinic acid) induces myopia in guinea pigs. 8:30am.
Myopia prevalence is markedly increasing in recent years and in some East Asian populations of tested young individuals its levels are approaching 100%. This visual developmental disease causes nearsightedness in which distant objects are perceived as being out of focus. In severe cases, complications can even lead to blindness. One of the factors possibly promoting such losses in visual acuity is a change in lifestyle requirements resulting from less time spent to outdoor daylight. Our studies are directed towards determining if curtailed outdoor exposure is associated with changes in retinal interneuronal communication. This is a relevant question because gap junction channel openings between neurons modulate light-induced signal transduction and propagation. A disturbance in this process may impair visual perception. To evaluate such a possibility, we hypothesized that selective drug-induced closure of retinal gap junctions affects myopia progression in guinea pigs. Our results showed that this prediction is correct because 18-β-glycyrrhetinic acid-induced retinal gap junction closure induced myopia in guinea pig. Accordingly, maintenance of interneuronal retinal gap junctional connectivity appears to contribute to supporting normal eye growth and vision.

Biochemistry/Molecular Biology
#508 - 5255 - B0142. Effect of High Energy Visible Light on A2E-loaded Retinal Pigmented Epithelium in Age-Related Macular Degeneration. 8:30am.
Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. The causes of the disease are not yet fully understood although we know that genetic background and environment are involved in the development of the disease. Some evidences indicate that sunlight exposure, and more specifically the blue portion, plays a role in the progression of AMD. More precisely, there is a molecule, called A2E, that absorbs blue light and this absorption is suspected to be toxic for the retina. To test our hypothesis, retinal cells filled with A2E at a concentration found in human eyes were exposed to blue light every day, 4 days a week during 11 weeks at a dose our eyes can be irradiated in real life. We then measured the effects on the cells using different stress markers and we found no effect of the blue light and A2E on retinal cells. Surprisingly, it seems that blue light degrades A2E, and would therefore be protective rather than toxic.

#508 - 5263 - B0150. Mitochondrial regulation of microRNA and implications for macular degeneration. 8:30am.
Age-related macular degeneration (AMD) is a leading cause of blindness in the world but there is variation in severity and responses to treatment among different patients. In order to develop effective treatments, it is critical to understand the causes of the disease and be able to screen patients to identify those who are most appropriate for certain medications. We hypothesize that the mitochondria can influence susceptibility and disease progression of AMD. The mitochondria are the power plants of the cell, providing energy for normal cellular processes. Using mitochondria obtained from a routine blood draw from individual patients, we can generate a "˜personalized' cell culture system referred to as a cybrid, which allows testing for responses to various treatments.

Our cybrid data shows that mitochondria from AMD patients cause cells to express different levels of key microRNA molecules that are relevant to AMD disease progression, driving inflammation and abnormal blood vessel growth. MicroRNA are powerful regulators of gene expression that are of great interest for a wide variety of diseases, and therefore could serve (a) as potential biomarkers for early diagnosis of AMD, and (b) as potential treatments to control the expression of harmful pathways.

Clinical/Epidemiologic Research
#539 - 5719 - B0257. Associations between the gut microbiome, a healthy diet, and age-related nuclear cataract. 11:30am.
Cataract - the clouding of the lens as the eye ages, is the leading cause of blindness in the world and a major public health problem. A healthy diet protects against the formation of cataract, possibly through antioxidant vitamins, but we do not know how exactly this happens. Gut bacteria have important functions in keeping us healthy as they generate nutrients from substrates that are otherwise indigestible. Therefore, we wanted to understand if a healthy diet influences which microbes are in the gut, and if these changes can be related to cataract. Our pilot study of 757 subjects from the UK (all part of the TwinsUK cohort) showed that there are differences between the gut bacteria in people who ate healthy diets compared to those who did not. Some of these bacteria, known to be important for digesting plant material, were associated with healthy diets and may protect against cataract. A bigger study is needed to better understand the role that bacteria play in cataract, and eye health in general.

Eye Movements/Strabismus/Amblyopia/Neuro-Ophthalmology
#504 - 5139 - B0026. Retrospective review of ocular pain management with eye removal surgery at Yale New Haven Hospital. 8:30am.
Patients who have eye removal surgery to alleviate pain have often had multiple prior treatments to save their eye and have been in pain for long periods of time. In clinic, some lament not having been referred for eye removal sooner. Our study quantified the amount of time between initial pain and definitive eye removal surgery for patients at Yale New Haven Hospital treated over the past three years and found the average time for all patients to be 13 weeks. Patients who had a blind painful eye due to more long-term diseases such as diabetes, glaucoma, or corneal ulcer had a much higher average time (21 weeks) between initial pain and surgery. In contrast, patients who had eye removal due to cancer had surgery within an average of 9 weeks, and patients with rupture of the eye or infection of the interior eye had eye removal within an average of 1 week. These results highlight the differences in how we manage eye removal patients based on the cause of their eye pain and bring attention to the long-term suffering these patients may be experiencing.

#504 - 5138 - B0025. Personalized 3D-printed conformers for the treatment of severe microphthalmia/ anophthalmia. 8:30am.
In children with anophthalmia and/or microphthalmia one eye or both eyes are respectively not developed or remain smaller than healthy eyes. Children suffering from this condition are at risk to develop facial deformation as a too small eye cannot appropriately stimulate growth of the facial bones. Currently used treatments include surgery and the use of expandable materials such as rapidly swelling gels to enlarge the eye cavity. These strategies are invasive and require hospitalization. As an alternative we developed a noninvasive personalized treatment strategy involving 3D-printed volume-increasing conformers. These conformers are small spheres or dishes that fit in the affected eye cavity. The principle of the treatment is to exchange the conformers for a slightly larger size at every step, which can be done at home, and thereby mimic the growth of a healthy eye. The design of the conformer was based on Magnetic Resonance Imaging (MRI) combined with a digitalized impression of the patient's eye cavity and the shape gradually changed with each step to form a suitably-shaped eye cavity for cosmetic prosthesis wear. Our research so far showed that our 3D-printed conformers are well-tolerated and noninvasively stimulate eye cavity expansion and eye lid fissure growth, creating facial symmetry.

#544 - 5852 - B0404. Neuro-Vascular changes associated with the Water Drinking Stress Test. 11:30am.
Drinking a lot of water in a short period of time increases pressure in the blood and inside the eye and reduces the electrical activity of the eye's nerve cells. Water Drinking Test (WDT) consists of drinking a liter of water within 5 minutes, and is commonly used to temporarily increase the pressure inside the eye and predict the risk of developing glaucoma, a blinding disease that is more severe in subjects with elevated eye pressure. The research demonstrates in normal subjects that the WDT also causes elevation of blood pressure and reduction of heart rate and the pattern electroretinogram, a measure of function of nerve cells susceptible to glaucoma. These changes represent additional risk factors for glaucoma and their assessment might increase the predictive power of the WDT for glaucoma development.

#540 - 5736 - B0288. Conditional, genetically-encoded, small molecule-regulated inhibition of NF-κB signaling in RPE cells. 11:30am.
Inflammation is a powerful weapon used by our bodies to eradicate viruses and foreign pathogens. As such, low levels of controlled inflammation are necessary to ensure a healthy, functioning eye. However, a number of both rare and prevalent eye diseases are likely caused by inflammation gone awry, unregulated inflammation that has detrimental consequences for cells involved in vision. Therefore, balance and tight regulation of inflammatory signaling must be achieved in order maintain eye health. Current methods to control detrimental inflammation in the eye rely on either permanent repression of inflammation or repeated injections of the eye with drugs that have substantial undesirable side effects. We have developed an approach that permits healthy inflammatory signaling while retaining the ability to dampen detrimental or "˜pathogenic' inflammation with the addition two harmless molecules. This method is tunable, reversible, and has been demonstrated to prevent inflammatory signaling associated with a number of stimuli. In theory, this approach can be targeted to particular layers within the eye, thereby avoiding off-target effects, and control of this strategy can be achieved by orally-administered small molecules. We are confident that this approach has the potential to significantly benefit human health through the treatment of inflammation-based eye disease.

Multidisciplinary Ophthalmic Imaging Group
#516 - 5432 - B0589. Motion-free en face OCT Angiography and Pigment Imaging based on Modified Lissajous Scan. 8:30am.
Although scanning speed of optical coherence tomography (OCT) has become faster and faster, it still take several seconds to scan 3D OCT volume typically, which allows eye motion. The eye motion results in image gaps and distortions in en face OCT images. We developed a software-based method to correct these eye motion artifacts. In our method, a modified Lissajous scanning pattern, which scan the entire volume for multiple times, is adopted as scanning protocol. With this residual scanning pattern, we can split the en face OCT images into small parts which have overlapping areas with some others. Remarkably, we necessarily split every image gaps to avoid these image gaps appear in final image. Using these overlapping areas, we can stitch small parts to build a motion-free image. In this stitching process, the large motion distorted small parts, which has low similarities with other small parts in their overlapping areas, were discarded. By confirming the effectiveness and validity of motion corrected images, we conclude that this method can provide motion-free en face OCT angiography and pigment images.

#547 - 5923 - B0659. Systemic complement activation in central serous chorioretinopathy. 11:30am.
The exact origin of the common and mysterious eye disease central serous chorioretinopathy (CSC) is still unknown. Several genes in the complement system, a part of the immune system, have been described to be associated with CSC. In age-related macular degeneration, a disease that overlaps with CSC, both genetic risk factors in and systemic activation of the complement system have been found. However, in this study in 76 CSC patients we found no evidence of either systemic activation or inhibition of the complement system, in comparison with 29 controls without ophthalmological history.

#547 - 5925 - B0661. Association between CFH variants and choroidal thickness in central serous chorioretinopathy. 11:30am.
Central serous chorioretinopathy (CSCR) is a common eye disease which affects the vision of middle aged people. The patients of CSCR show a pooling of water at the posterior part of the eye. Some risk factors of CSCR such as hormone imbalance, psychogenic stress and pregnancy were reported, but the details why CSCR occurs are unknown to date. We thought that some genetic factors may contribute to this disease and firstly reported the association of genetic variants of complement factor H (CFH), a multifunctional molecule which regulates inflammation and circulation, with CSCR. In the present study, we have further demonstrated that the variants of CFH gene may be associated with a thickening of the choroid, a membrane of abundant blood vessels spread-out at the posterior inner surface of the eye, which may be correlated with the posterior ocular circulation. This finding may be a clue to disclose the molecular mechanisms of CSCR.

#521 - 5537 - B0737. Peripapillary Pigmentation and Optic Disc Morphology in Newborns with Treatment-Warranted Retinopathy of Prematurity. 8:30am.
Retinopathy of Prematurity (ROP) is a disease of the retina, or the back layer of the eye, that occurs in premature babies and can lead to blindness if left untreated. Little is known about the changes in pigmentation around the optic nerve or in optic nerve morphology during the progression of severe ROP requiring treatment intervention (treatment-warranted ROP [TW-ROP]). Using images obtained from the Stanford University Network for Diagnosis of Retinopathy of Prematurity (SUNDROP), an initiative to screen premature babies in Northern California for ROP, we compared TW-ROP babies with non-TW-ROP babies. We found that the change in optic nerve area from the first to last screening eye exam was not significantly different between the two groups. However, TW-ROP babies had a greater increase in area of pigmentation around the optic nerve and the pigmentation became darker from the first to last screening eye exams when compared to non-TW-ROP babies. Further studies into these changes may be used to help guide patient selection for treatment of ROP in the future.

Retinal Cell Biology
#546 - 5905 - B0497. An Avian Adeno-Associated Viral Vector for Visualization of Post-Natal Chick Retinal Circuitry. 11:30am.
Gene therapy refers to the ability of scientists and clinicians to alter gene expression within a patient or animal model using a variety of techniques. One of these involves the use of engineered viral vectors, which have been used prolifically in recent years in neuroscience research and clinical trials. The post-hatching chick is a valuable model for visual research, but unfortunately lacks gene therapy tools available to the more typical rat and mouse models. This research represents the first attempt to adapt an avian serotype of a commonly used viral vector for use in the retina in basic scientific research. We show that injection of avian virus into the eye is sufficient to manipulate gene expression in a minority of cells, and use this technique to visualize retinal cells and their circuitry in situ by forcing expression of a fluorescent marker. Further, we show that transduction efficiency can be drastically increased by directly exposing isolated retinas to the virus in culture. This suggests that techniques that increase viral contact with the retina in vivo may increase transduction efficiency to scientifically useful levels. Overall, this research provides the foundational data for a gene therapy vector which - with further development - may transform the chick into an indispensable model for determination of retinal function and circuitry.

Katrina Norfleet


Posted: 5/11/2017