Advances in sight-loss prevention: is it any better?

According to a World Health Organisation (WHO) report, there’s an estimated 285 million visually impaired people worldwide. Of those, 39 million are defined as totally blind, while 246 million possess varying levels of low vision. Around 90% reside in low-income populations.{{image2-a:r-w:400}}Uncorrected refractive errors are the leading causes of moderate to severe visual impairment, while cataracts are the primary culprit for blindness in low and middle-income groups.However, while the report found there had been a significant drop in the number of people visually-impaired by infectious diseases in the last 20 years, 80% of all people with visual impairments suffered from afflictions that were preventable or curable.Governments have established policies and provided funding for medical research to address these large-scale eye probls, while private and civic organisations also offer grants and funding in an attpt to devise a cure for blindness. Yet, most of those affected lack access to sufficient primary care services and institutions.So, the question must be asked: To what extent has science and technology advanced the cause and is it any closer to reversing blindness and making eye disease a thing of the past?Reversing eye damageA team of international researchers has found a way to repair the effects of degenerative eye diseases by reprogramming mutated rod photoreceptors to make functional cone photoreceptors.With the use of the CRISPR/Cas9 gene-editing tool, the scientists reversed cellular degeneration, which restored visual functions on two test mice with retinitis pigmentosa (RP).{{quote-A:R-W:470-I:5-Q:“Cone cells are less vulnerable to the genetic mutations that cause RP. Our strategy was to use gene therapy to make the underlying mutations irrelevant, resulting in the preservation of tissue and vision,”-WHO:Dr Kang Zhang, Chief of Ophthalmic Genetics and Founding Director of the Institute for Genomic Medicine at UC San Diego School of Medicine}}Published in the online journal Cell Research, the technique was developed by a collaborative research team from the University of California San Diego School of Medicine, Shiley Eye Institute and geneticists from China.Senior study author Dr Kang Zhang, chief of ophthalmic genetics and founding director of the Institute for Genomic Medicine at UC San Diego School of Medicine, said his team had used CRISPR/Cas9 to specifically deactivate Nr1 and Nr2e3, and reprogram the rod cells to produce cone cells.“Cone cells are less vulnerable to the genetic mutations that cause RP. Our strategy was to use gene therapy to make the underlying mutations irrelevant, resulting in the preservation of tissue and vision,” Zhang said.The process resulted in an abundance of reprogrammed cone cells that preserved the cellular structure in the retina.“There is no treatment for RP so the need is great and pressing. In addition, our approach of reprogramming mutation-sensitive cells to mutation-resistant cells may have broader application to other human diseases, including cancer,” Zhang pointed out.The researchers are about to complete the preclinical study to make way for human clinical trials. They will be using the adeno-associated virus (AAV) for the gene therapy process, which is commonly used in most successful genetic treatments due to its safety profile.The findings of the study were supported with electro-retinography testing of cone and rod receptors that showed significantly improved retinal functions in the two test mice. A similar conclusion was also reported in an independent study conducted by Dr Zhijian Wu from the National Eye Institute.No more reading glassesIn the US, there are an estimated 11 million people with presbyopia, most of whom rely on a pair of reading glasses. Even with the absence of any eye disease such as cataracts, macular degeneration or diabetic retinopathy, presbyopia comes with age.However, a company called Revision Optics based in California has developed a corneal inlay, which is surgically implanted to reshape the front of the eye to restore near vision. The product is called Raindrop and is reported to provide a long-term solution against presbyopia, eliminating the need to wear reading spectacles. The hydrogel inlay, 80% of which is comprised of water, is placed surgically below the surface of the eye and the procedure takes only 10–15 minutes.Patients who have undergone the procedure have recorded an average improvent of five lines of near vision on a standard eye chart within a week after Raindrop is implanted. After two years, 98% of patients in a test group showed 6/12 or better visual acuity at near distance and 76% regained 6/7.5 or better at intermediate distance, clear enough to read ails on a computer screen.However, while Raindrop has been approved for use in Australia, it costs thousands of dollars and is not covered by Medicare, meaning only those with prium private health insurance policies or a substantial disposable income are able to access its benefits. It’s a similar story in other countries where Raindrop is available.New hope for AMD patientsStatistics from the WHO indicate that age-related macular degeneration (AMD) is the primary cause of visual deficiency in industrialised countries and ranks third among the global causes of visual impairment, with a blindness prevalence of 8.7%.{{quote-A:R-W:470-I:6-Q:“Efficacious self-administered drug application by eye drop would lead to a significant reduction in adverse outcomes and healthcare costs compared with current treatments,”-WHO:Dr Felicity de Cogan, Biochist from the University of Birmingham’s Institute of Inflammation and Ageing}}While there is no approved treatment for dry-AMD, current anti-VEGF treatment for people with wet-AMD is highly effective. However, it is not without drawbacks. The nature of the treatment – repeated painful eye injections, often indefinitely – has been known to cause anxiety and depression among patients, while also increasing the risk of infection.As the University of Birmingham’s Dr Felicity de Cogan points out, these negative aspects of the treatment are resulting in a lack of compliance from patients, which is significantly hampering efforts to control the spread of the disease.To combat this, de Cogan and her team have developed a new type of eye drops with cell-penetrating peptides (CPP) that could help prevent the progression of the disease without the need for injections.“The CPP-drug has the potential to have a significant impact on the treatment of AMD by revolutionising drug-delivery options. Efficacious self-administered drug application by eye drop would lead to a significant reduction in adverse outcomes and healthcare costs compared with current treatments,” de Cogan said.“The CPP-plus drug complex also has potential application to other chronic ocular diseases that require drug delivery to the posterior chamber of the eye, and we believe this is going to be very important in terms of powering of patients and reducing the cost of treatment.”Early detection through deep learningDiabetic retinopathy (DR) is among the top causes of blindness around the world and affects one in three people with diabetes. However, early detection and treatment can lower the risk of contracting the disease by 95%.{{quote-A:L-W:450-I:7-Q:“Recent advancents in deep learning and image analytics technologies are showing significant promise in the potential to help solve some of the greatest health challenges we face today.”-WHO:Dr Joanna Batstone, Vice President and Lab Director of IBM Research Australia}}As a result, international researchers are attpting to use the constant advances in computer science, artificial intelligence and ‘deep learning’ to effectively screen for the disease.Currently, these efforts appear to be being led by the team from IBM Research Australia, which has developed a syst using visual analytics and deep learning for the early detection of DR.The new technology assessed more than 35,000 eye scans to help train it to analyse data and identify haorrhages, micro-aneurysms, and exudates. It then classified the different severity levels of DR by combining deep learning processes, convolutional neural networks (CNN) and dictionary-based learning for DR-specific pathologies.“Recent advancents in deep learning and image analytics technologies are showing significant promise in the potential to help solve some of the greatest health challenges we face today,” Dr Joanna Batstone, vice president and lab director of IBM Research Australia said, adding “Automated and highly accurate DR screening methods have the potential to help doctors screen far more patients than currently possible.”The Centre for Eye Research Australia’s principal investigator, Dr Peter van Wijngaarden explained the importance of this work by saying, “The alarming projections of the number of patients with diabetic retinopathy have major implications for the health syst. The loss of vision from the condition can impose an enormous burden on the individual, including a loss of capacity to work and the need for intensive community support.”{{quote-A:R-W:470-I:8-Q:“There is a real need for innovation to improve effective screening of those who are at risk to enable early sight-saving treatment.”-WHO:Peter van Wijngaarden, Principal Investigator at the Centre for Eye Research Australia}}“To substantially reduce the number of people unnecessarily losing vision from diabetic eye disease, there is a real need for innovation to improve effective screening of those who are at risk to enable early sight-saving treatment.”Over time, IBM Research scientists will aim to further advance the syst in order to increase its understanding of DR and the pathologies manifested in the retina from the disease.Prevention is better than cureTechnology is still far roved from curing all forms of blindness and, more than likely, never will.However, the advances in early detection for most forms of common eye disease and the methods used to treat th provide hope for the future. The examples provided in this article are but a few of the hundreds of different studies occurring all over the world which, in one way or another, are aiming to dramatically decrease, or rid the world of blindness.But technology cannot fight the battle alone. For example, we already have a proven, simple cure for cataract, yet it is still responsible for more than half of the world’s blindness.Efforts to change the status quo are being made, either through government programs or charitable initiatives, but easy access to affordable eyecare still lags far behind the progress being made in the world’s best labs. Until that issue is resolved, even the most amazing technological advances will still mean nothing to 90% of the world’s visually impaired, who instead se destined to be blind by virtue of the fact of their birthplace.