Limitations and advances in new treatments and future perspectives of corneal blindness / Limitações e avanços em novos tratamentos e perspectivas futuras na cegueira corneal

ABSTRACT This review is intended to describe the therapeutic approaches for corneal blindness, detailing the steps and elements involved in corneal wound healing. It also presents the limitations of the actual surgical and pharmacological strategies used to restore and maintain corneal transparency in terms of long-term survival and geographic coverage. In addition, we critically review the perspectives of anabolic agents, including vitamin A, hormones, growth factors, and novel promitotic and anti-inflammatory modulators, to assist corneal wound healing. We discuss the studies involving nanotechnology, gene therapy, and tissue reengineering as potential future strategies to work solely or in combination with corneal surgery to prevent or revert corneal blindness.(AU)

RESUMO O presente trabalho traz uma revisão das abordagens terapêuticas para a cegueira da córnea. O estudo detalha as etapas e os elementos envolvidos na cicatrização da córnea. Ele mostra as limitações das estratégias cirúrgicas e farmacológicas usadas para restaurar e manter a transparência da córnea em termos de sobrevida a longo prazo e alcance geográfico. As perspectivas dos agentes anabólicos, incluindo vitamina A, hormônios, fatores de crescimento e novos moduladores pró-mitóticos e anti-inflamatórios para auxiliar a cicatrização da ferida na córnea, são revisadas criticamente. Aqui, apresentamos estudos envolvendo nanotecnologia, terapia gênica e reengenharia de tecidos como possíveis estratégias futuras para atuar de maneira isolada ou combinada com a cirurgia da córnea para prevenir ou reverter a cegueira corneana.(AU)

Corneal blindness in Platos cave: the acting forces to prevent and revert corneal opacity. Part I: epidemiology and new physiopathological concepts / A cegueira corneal na caverna de Platão: as forças para prevenir e reverter a opacidade da córnea. Parte I: epidemiologia e novos conceitos na fisiopatologia

ABSTRACT The burden of corneal blindness and visual deficiency can be felt worldwide. Its association with several endemic diseases such as childhood blindness, trauma, infectious keratitis (including variants caused by herpes, hanseniasis, and fungi), vitamin A deficiency, diabetes mellitus, and other dry eye syndromes reflects its poorly understood underlying mechanisms and suggests that the actual frequency of the disease is underestimated. The low effectiveness of preventive and therapeutic strategies against corneal scarring or deformity predicts a high frequency of patients with corneal blindness in the future. Corneal blindness is associated with environmental factors and socioeconomic limitations that restrain health assistance and maintain a modest efficiency of the current therapeutic strategies for resolving corneal diseases in large-scale programs. We present here a critical review of the concepts associated with corneal blindness that need to be considered when planning strategies to prevent and treat corneal blindness worldwide (to be able to leave Plato's cave, where corneal blindness is encaged.

RESUMO O problema da deficiência visual e da cegueira corneal abrange o mundo todo e corresponde à quarta causa de cegueira e deficiência visual, com acometimento estimado de mais de 16 milhões de pessoas. A associação com várias doenças endêmicas, como cegueira infantil, trauma, ceratites infecciosas (incluindo herpes, hanseníase e fungos), hipovitaminose A, diabetes mellitus e outras causas de síndromes de olho seco, indicam que a verdadeira frequência é subestimada e que os diferentes mecanismos são pouco conhecidos. A baixa eficácia na prevenção e tratamento da cicatriz e deformidade da córnea permite antecipar que a prevalência da cegueira corneal irá crescer no futuro. As razões para o aumento da cegueira corneal envolvem fatores ambientais, limitações socioeconômicas para ampliar a assistência à saúde e a modesta eficiência das estratégias terapêuticas para resolver o problema em grande escala. O presente trabalho traz uma revisão crítica dos conceitos associados à cegueira corneal. Essa análise é uma etapa necessária para preparar o caminho com o objetivo de deixar a caverna que encarcera a cegueira corneal, em analogia ao mito de Platão, e melhorar as estratégias para prevenir e tratar a cegueira corneal em escala mundial.

Turning the tide of corneal blindness.

Corneal diseases represent the second leading cause of blindness in most developing world countries. Worldwide, major investments in public health infrastructure and primary eye care services have built a strong foundation for preventing future corneal blindness. However, there are an estimated 4.9 million bilaterally corneal blind persons worldwide who could potentially have their sight restored through corneal transplantation. Traditionally, barriers to increased corneal transplantation have been daunting, with limited tissue availability and lack of trained corneal surgeons making widespread keratoplasty services cost prohibitive and logistically unfeasible. The ascendancy of cataract surgical rates and more robust eye care infrastructure of several Asian and African countries now provide a solid base from which to dramatically expand corneal transplantation rates. India emerges as a clear global priority as it has the world's largest corneal blind population and strong infrastructural readiness to rapidly scale its keratoplasty numbers. Technological modernization of the eye bank infrastructure must follow suit. Two key factors are the development of professional eye bank managers and the establishment of Hospital Cornea Recovery Programs. Recent adaptation of these modern eye banking models in India have led to corresponding high growth rates in the procurement of transplantable tissues, improved utilization rates, operating efficiency realization, and increased financial sustainability. The widespread adaptation of lamellar keratoplasty techniques also holds promise to improve corneal transplant success rates. The global ophthalmic community is now poised to scale up widespread access to corneal transplantation to meet the needs of the millions who are currently blind.

Millennium development goals and eye health.

In September 2000, world leaders made a commitment to build a more equitable, prosperous and safer world by 2015 and launched the Millennium Development Goals (MDGs). In the previous year, the World Health Organization and the International Agency for the Prevention of Blindness in partnership launched the global initiative to eliminate avoidable blindness by the year 2020–VISION 2020 the Right to Sight. It has focused on the prevention of a disability-blindness and recognized a health issue–sight as a human right. Both global initiatives have made considerable progress with synergy especially on MDG 1–the reduction of poverty and the reduction in numbers of the blind. A review of the MDGs has identified the need to address disparities within and between countries, quality, and disability. Noncommunicable diseases are emerging as a challenge to the MDGs and Vision 2020:0 the Right to Sight. For the future, up to and beyond 2015, there will be need for both initiatives to continue to work in synergy to address present and emerging challenges.

What the comprehensive economics of blindness and visual impairment can help us understand.

Since the year 2000, the amount written about the economics of blindness and visual impairment has increased substantially. In some cases, the studies listed under this heading are calculations of the costs related to vision impairment and blindness at a national or global level; in other cases the studies examine the cost-effectiveness of strategies to prevent or modify visual impairment or blindness that are intended to be applied as a guide to treatment recommendations and coverage decisions. In each case the references are just examples of many that could be cited. These important studies have helped advocates, policy makers, practitioners, educators, and others interested in eye and vision health to understand the magnitude of the impact that visual impairment and blindness have on the world, regions, nations, and individuals and the tradeoffs that need to be made to limit the impact. However, these studies only begin to tap into the insights that economic logic might offer to those interested in this field. This paper presents multiple case studies that demonstrate that the economics of blindness and visual impairment encompasses much more than simply measures of the burden of the condition. Case studies demonstrating the usefulness of economic insight include analysis of the prevention of conditions that lead to impairment, decisions about refractive error and presbyopia, decisions about disease and injury treatment, decisions about behavior among those with uncorrectable impairment, and decisions about how to regulate the market all have important economic inputs.

Integrated model of primary and secondary eye care for underserved rural areas: The L V Prasad Eye Institute experience.

Blindness is a major global public health problem and recent estimates from World Health Organization (WHO) showed that in India there were 62 million visually impaired, of whom 8 million are blind. The Andhra Pradesh Eye Disease Study (APEDS) provided a comprehensive estimate for prevalence and causes of blindness for the state of Andhra Pradesh (AP). It also highlighted that uptake of services was also an issue, predominantly among lower socio-economic groups, women, and rural populations. On the basis of this analysis, L V Prasad Eye Institute (LVPEI) developed a pyramidal model of eye care delivery. This article describes the LVPEI eye care delivery model. The article discusses infrastructure development, human resource development, and service delivery (including prevention and promotion) in the context of primary and secondary care service delivery in rural areas. The article also alludes to opportunities for research at these levels of service delivery and the amenability of the evidence generated at these levels of the LVPEI eye health pyramid for advocacy and policy planning. In addition, management issues related to the sustainability of service delivery in rural areas are discussed. The article highlights the key factors required for the success of the LVPEI rural service delivery model and discusses challenges that need to be overcome to replicate the model. The article concludes by noting the potential to convert these challenges into opportunities by integrating certain aspects of the existing healthcare system into the model. Examples include screening of diabetes and diabetic retinopathy in order to promote higher community participation. The results of such integration can serve as evidence for advocacy and policy.

Best practice eye care models.

Since the launching of Global Initiative, VISION 2020 “the Right to Sight” many innovative, practical and unique comprehensive eye care services provision models have evolved targeting the underserved populations in different parts of the World. At places the rapid assessment of the burden of eye diseases in confined areas or utilizing the key informants for identification of eye diseases in the communities are promoted for better planning and evidence based advocacy for getting / allocation of resources for eye care. Similarly for detection and management of diabetes related blindness, retinopathy of prematurity and avoidable blindness at primary level, the major obstacles are confronted in reaching to them in a cost effective manner and then management of the identified patients accordingly. In this regard, the concept of tele-ophthalmology model sounds to be the best solution. Whereas other models on comprehensive eye care services provision have been emphasizing on surgical output through innovative scales of economy that generate income for the program and ensure its sustainability, while guaranteeing treatment of the poorest of the poor.

Causas e características do trauma ocular perfurante em Botucatu - SP / Causes and characteristics of perfurant ocular traumas in Botucatu - SP

O trauma ocular perfurante é importante causa de cegueira prevenível. Há necessidade de conhecer suas causas para tomada de medidas preventivas. Para tal, avaliamos os traumas perfurantes atendidos no H.C. da FMB-UNESP, nos últimos 5 anos. Observamos que a maioria dos caos ocorreu em indivíduos masculinos 73 (por cento), crianças e adultos jovens, em atividades domesticas 77,92 (por cento), geralmente provocados por objetos metálicos 40,54 (por cento), sendo mais frequente a perfuraçäo corneoescleral 46,75 (por cento). A gravidade do trauma perfurante é constatada pelo número expressivo de cegos (AV menor que 0,1) no final do tratamento

Trauma ocular e endoftalmite / Ocular trauma and endophthalmitis

O trauma ocular, causa comum de cegueira unilateral, é mais frequente em crianças e adultos jovens (predominantemente do sexo masculino). Habitualmente é provocado por agressöes, acidentes domésticos e com veículos motores e constitue a quarta causa mais importante de cegueira na maioria dos países da America LAtina. Em decorrênciade trauma ocular penetrante, um microrganismo pode ter acesso ao lho, com ou sem a presença de corpo estranho intra-ocular, ou mesmo após uma perfuraçäo auto-selante (selt sealing). Neste estudo, na Fundaçäo e Instituto Hilton Rocha, em Belo Horizonte, o autor analisa 213 casos de trauma ocular, em pacientes de 1979 a 1993. O estudo confirma dados da literatura concernentes a idade, tipo de acidente, os sinais oculares mais frequentes, o manejo do trauma ocular, etc. É nessaltada a ocorrência de endoftalmite, sua profilaxia e tratamento, e os organismos infectantes mais frequentes, assim como outros aspectos importantes da literatura

Detection of hepatitis B virus by in situ hybridization in corneal tissues of HBs AG positive donors

HBV is a hepatotropic virus. The highest concentration found in the blood and liver with lower amount in saliva and semen. The virus was also detected in body fluids. Keratoplasty is an essential operation for the treatment of corneal blindness. At Ain Shams University International Eye Bank 10% of the collected corneas were from donors with HBs antigenemia. These corneas were rejected according to the Eye Bank Association of America. In this study 32 corneal tissues of 16 donors positive HBsAg were examined for the presence of HBV by in situ DNA hybridization technique to detect HBV DNA in the corneal sections This marker could not be seen in this work This preliminary study could be an encouraging step for further researches to, evaluate the possibility of the avascular cornea to carry HBV

Untreatable monocular blindness in pakistani eye patients

To determine the incidence of untreatable [at least by means currently available in Pakistan] monocular blindness in our hospital-based population, we examined 1,710 consective patients admitted to the Department of Ophthamology, Lady Reading Hospital, Postgraduate Medical Institute, Peshawar from September 17, 1990 to January 1991. Seven percent [235] of the patients had monocular blindness with visual acuity of 3/60 [10/200] or less in the affected eye. Out of these 235 patients, visual loss in 94 [40%] was due to trauma, in 51 [21.7%] due to corneal opacification from various corneal diseases, in 41 [71.4%] due to end-stage glaucoma [33 with primary glaucoma and eight with secondary glaucoma], in 15 [6.3%] from postoperative infection following cataract surgery, in 14 [5.9%] due to optic atrophy, and in the remainder 20 [8.5%] due to miscellanous causes, including retinoblastoma [four cases], retinal detachment [three cases], panophthalmitis [two cases], spontaneous rupture of an anterior staphyloma [two cases], basal cell carcinoma of eyelid invading the orbit [two cases], squamous cell carcinoma of conjunctiva involving globe [two cases], microphthamos, proptosis complications, explusive choroidal hemorrhage during cataract extraction, myopic degeneration, and diabetic retinopathy [one case each]. That only one patient had visual loss due to diabetic retinopathy is interesting. The overall incidence of monocular blindness in Pakistan can be significantly reduced by adequate and timely preventive and therapeutic measures against ocular trauma and corneal disease, the two leading causes of blindness. The recent heavy influx of the Afghan refugees of Russian aggression of their country might increased the incidence of trauma in our area. [Pakistan Journal of Ophthalmology 8:3-5, January, 1992]

Estimulaçäo precoce na ambliopia: curso sobre orientaçäo educacional pra crianças com visäo sub normal / Precocious stimulation in the amblyopia: course about educational guidelines for children with subnormal vision

As crianças com visäo subnormal devem ser submetidas a programas de estimulaçäo precoce, iniciada desde o primeiro ano de vida, que consiste em aplicaçäo de métodos integrados sensorialmente de estimulaçäo táctil, auditiva e visual. Com a evoluçäo inicia-se também um processo de correçäo postural visando a posiçäo de pé e a de ambulaçäo. A finalidade do método consiste finalmente em devolver a criança uma capacidade de exercer todas as funçöes sensoriais e motoras que näo estäo comprometidas organicamente fazendo-a ser aceita pela comunidade e permitindo-lhe satisfazer suas próprias necessidades econômicas