Vision and vision loss.

To provide supportive and effective care to people who must adapt to blindness or visual impairment, nurses and other health care professionals have a responsibility to be knowledgeable about the unique effect of ophthalmic disorders on the body, spirit, and mind. It is also evident that nurses must clearly understand their own emotions and social reactions to blindness and visual loss so that they can more clearly assist their clients through adaptation.     

Stemming vision loss with stem cells

Dramatic advances in the field of stem cell research have raised the possibility of using these cells to treat a variety of diseases. The eye is an excellent target organ for such cell-based therapeutics due to its ready accessibility, the prevalence of vasculo- and neurodegenerative diseases affecting vision, and the availability of animal models to demonstrate proof of concept. In fact, stem cell therapies have already been applied to the treatment of disease affecting the ocular surface, leading to preservation of vision. Diseases in the back of the eye, such as macular degeneration, diabetic retinopathy, and inherited retinal degenerations, present greater challenges, but rapidly emerging stem cell technologies hold the promise of autologous grafts to stabilize vision loss through cellular replacement or paracrine rescue effects.Stem cell–based therapy represents a newly emerging therapeutic approach by which vascular and neuronal degenerative diseases may be treated. Since most of the diseases that lead to loss of vision do so as a result of abnormal vasculature and/or neuronal degeneration, the use of stem cells to stabilize or prevent visual loss may hold great promise. The eye is a highly vascular organ whose function is to gather light, focus it (through the cornea and lens) onto a thin, highly vascular neuronal tissue (the retina), transduce the light energy into electrical signals, transmit these signals via neurons to the visual cortex of the brain, and, finally, transform these electrical signals into an image or images that we perceive as “vision.” Abnormalities in any part of the visual pathway, phototransduction machinery, neuronal pathways, or the visual cortex can lead to loss of vision. Most commonly, these abnormalities result from problems with the vasculature (e.g., ischemia or leakage) or the neurons themselves (e.g., genetic disease or degeneration secondary to hypoxia or toxicity), although ancillary structures of the eye that regulate intraocular fluid homeostasis (leading to glaucoma) or light transmission (leading to scarring of the front of the eye or cataract) can also be damaged sufficiently to lead to loss of vision. The potential clinical utility of stem cells could come from actual replacement of damaged cells with healthy ones generated from stem cells or through a paracrine effect of the stem cells that would help maintain a healthy tissue microenvironment or attract endogenous, circulating progenitor cells to help repair damaged cells in the eye. There has been enormous enthusiasm for exploring the potential utility of stem cells for a variety of diseases, including those of the eye, but much of this needs to be tempered by the reality of, first, needing to understand the underlying diseases and, second, finding the appropriate stem cell population and determining whether the potential benefit is outweighed by potential harm. In this article, we will discuss the ocular diseases potentially treatable with stem cell therapies, the various types of stem cells that may find therapeutic application, and the safety and production issues that need to be addressed before such therapies can be effectively used in the clinics.The eye is divided into two anatomic regions (Figure ​(Figure1),1), the anterior segment (containing the conjunctiva, cornea, trabecular meshwork [TM], and iris) and the posterior segment (consisting of the lens, vitreous, retina, and choroid/choriocapillaris). General pathological principles apply to the tissues of both segments, but inflammatory, infectious, and vascular diseases are more characteristic of diseases observed in the anterior segment while these three classes of disease plus degenerative/genetic problems are also observed in the posterior part. Certain parts of the eye (e.g., the retina) are highly vascular and, thus, more commonly experience diseases associated with abnormal blood vessels and associated cells (e.g., diabetic retinopathy [DR] and hypertensive retinopathies). Open in a separate windowFigure 1Schematic representation of the eye with images of diseases associated with different regions of the eye that may be amenable to treatment with stem cells.As discussed in the text, the eye can be divided into anterior and posterior segments with different diseases characteristic of these segments. Diseases that would be potentially treated with stem cell–based therapies include corneal opacification (image reproduced with permission from the New England Journal of Medicine; ref. 9) and glaucoma (enlarged optic nerve head cup/disc ratio). Glaucoma is typically considered a disease of the anterior segment, since treatments have historically been directed at decreasing fluid production or increasing fluid outflow by targeting the ciliary body or TM, respectively. The vision-threatening pathology, however, is in the posterior segment principally affecting the ganglion cells and optic nerve. In the posterior segment, degenerative neuronal diseases could include those affecting photoreceptors such as retinitis pigmentosa and the photoreceptors and retinal pigmented epithelium such as atrophic macular degeneration. Retinal vascular diseases of the posterior segment would include DR and neovascular macular degeneration. Stem cells are unspecialized cells capable of self renewal through cell division, and, under certain physiological or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions (1). Stem cells can be derived and/or obtained from tissues of early embryos or adults and, under appropriate conditions, will differentiate into more than one mature and functional cell type (2, 3). Stem cells have been identified in a variety of adult tissues as well as in cord and peripheral blood and adult BM. These cells represent a pool of progenitor cells that may serve to provide replacement cells critical to the maintenance of various tissue types. They could also be harnessed for the repair of damaged tissue following injury or stress. Stem cells that have the capacity to differentiate into any cell type are referred to as pluripotent; these are similar to cells obtained from the early dividing embryo (e.g., the epiblast tissue of the inner cell mass of a blastocyst or earlier morula stage embryos). Other types of stem cells may be more restrictive in their differentiation abilities, and a more restrictive destiny is characterized by a progenitor cell. Progenitor cells are a type of cell that has committed to a specific cell lineage, is capable of undergoing limited replication, and is not yet expressing the characteristics associated with the mature cell type. Adult stem cells may have wide utility in the treatment of many eye diseases, as discussed below. In the appropriate microenvironment of many different tissues, these cells will target to sites of injury (vascular as well as neuronal), differentiate into various cell types, and contribute to the stabilization of degenerating tissue (4, 5). Newly emerging paradigms describing the existence of trophic “crosstalk” between local vascular networks and the tissues they supply and, thus, potential applications of these cells include not only cell-based therapeutic delivery of various trophic and static substances, but also use as stabilizing elements in an otherwise unstable environment of the type observed in ischemic retinopathies, retinal degenerative diseases, glaucoma, and corneal injuries. Here, we review newly emerging concepts and technologies in stem cell biology that have potential application to the treatment of vascular and neurodegenerative diseases of the eye. If successful, these studies will lead to the development and application of novel cell-based therapies for these currently untreatable diseases.     

Participation of the elderly after vision loss

Purpose.?To assess the degree of participation of the visually impaired elderly and to make a comparison with population-based reference data.

Method.?This cross-sectional study included visually impaired elderly persons (≥55 years; n?=?173) who were referred to a low-vision rehabilitation centre. Based on the International Classification of Functioning, Disability and Health (ICF) participation in: (1) domestic life, (2) interpersonal interactions and relationships, (3) major life areas, and (4) community, social and civic life was assessed by means of telephone interviews. In addition, we assessed perceived participation restrictions.

Results.?Comparison with reference data of the elderly showed that visually impaired elderly persons participated less in heavy household activities, recreational activities and sports activities. No differences were found for the interpersonal interactions and relationships domain. Participants experienced restrictions in household activities (84%), socializing (53%), paid or voluntary work (92%), and leisure activities (88%).

Conclusions.?Visually impaired elderly persons participate in society, but they participate less than their peers. They experience restrictions as a result of vision loss. These findings are relevant, since participation is an indicator for successful aging and has a positive influence on health and subjective well-being.     

Intracranial plasmacytoma causing acute unilateral loss of vision

Sir, Some patients with multiple myeloma may present with neurologicalcomplaints,¹ but intracranial plasmacytomas are rare. We describea patient with a plasmacytoma compressing the optic nerve, causingunilateral loss of vision as the first presentation of multiplemyeloma. A previously healthy 62-year-old man consulted his ophthalmologistbecause of sudden     

Staying connected: re-establishing social relationships following vision loss

Objective: To examine the nature of relationship-related challenges experienced by adults with vision impairment, as well as the strategies employed to deal with them.Design: Cross-sectional qualitative study.Setting: Vision rehabilitation agency.Subjects: Fifty-eight young, middle-aged and older adults with vision impairment.Method: Telephone and in-person interviews included an open-ended question about how having a vision impairment has changed relationships. Interviews were coded using a qualitative analytical approach.Results: Participants' responses fell into two categories: difficulty in social situations was due either to other people's lack of understanding and/or one's own lack of visual cues. Responses were either to readjust one's behaviour to maintain relationships or to let relationships go or turn sour. Within these two directions, participants reported specific strategies. For readjusting one's behaviour, participants mentioned explaining themselves more and being more assertive, relying on other senses for information, 'faking' it through interactions, and being more selective about who they interacted with. For letting relationships go, participants reported either withdrawing and making fewer initiatives to socialize, or getting angry and telling people off.Conclusions: Study findings suggest that re-establishing relationships following vision loss is a multifaceted experience in which individuals employ different strategies. These need to be further researched, given their importance to individuals dealing with vision impairment.     

Painless transient monocular loss of vision resulting from angle-closure glaucoma

The main symptoms of acute primary angle-closure glaucoma (PACG) include pain in the head and/or the eyes in addition to the characteristic halo and blurred vision. When loss of vision is accompanied by such pain, PACG is usually suspected. However, no information has been available regarding painless acute angle-closure glaucoma. Recently, we treated a patient with painless acute PACG mimicking amaurosis fugax as a type of transient ischemic attack. Generally, amaurosis fugax causes transient monocular loss of vision due to occlusion of the ophthalmic artery. The formation of microemboli derived from the heart or carotid artery and/or the occurrence of some hemodynamic abnormality due to arteriosclerosis is closely related to amaurosis fugax, and most cases are complicated by intracranial or extracranial arterial lesions. In the present case, we provisionally diagnosed transient amaurosis fugax which, however, was shown by additional ocular testing to be painless PACG. Herein we describe our diagnostic process and the outcome.     

Syphilis and vision loss: A role for point-of-care ultrasound

Vision loss in young adults is relatively rare. In patients with suspected HIV or syphilis, the risk of developing vision loss is increased, and should alert the emergency physician of specific retinal pathologies. We present a case of a 33-year-old man with recently identified syphilis and HIV, who was diagnosed with bilateral retinal detachments (RDs) with the help of point-of-care ultrasound (POCUS) in the setting of panuveitis (preventing visualization with direct fundoscopy).