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      Corneal transplantation at Tenwek Hospital, Kenya, East Africa: Analysis of outcomes and associated patient socioeconomic characteristics

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          Abstract

          Purpose

          To review the graft survival rate, visual outcomes, and patient demographics of primary penetrating keratoplasty performed at Tenwek Hospital, a mission hospital in rural Kenya.

          Methods

          A retrospective review was performed of the clinical records of patients who underwent primary penetrating keratoplasty for optical purposes from January 2012 to October 2014. The graft survival rates were constructed using the Kaplan-Meier method, and the effect of clinical and socioeconomic characteristics on time to graft failure were examined using Cox regression models.

          Results

          118 patients met the inclusion criteria. The most common indication for surgery was keratoconus (66.1%), followed by corneal scar (22.0%). Despite all patients giving a verbal commitment to do so, 40 patients (33.9%) failed to make it to followup one year postoperatively. Graft survival at one year, inclusive of all indications, was 85.8%. Of the different indications, keratoconus had the highest one-year graft survival rate of 89.9%. Compared to the preoperative uncorrected visual acuity, 85.3% achieved an improvement at one year. Compared to patients who had completed college or university, the risk of developing graft failure was 4.7 times higher among patients with less education (P = 0.01).

          Conclusions

          Corneal transplantation at Tenwek Hospital can be performed with a reasonable chance of success at one year, particularly in cases of keratoconus and in patients with higher educational backgrounds. Adherence to followup recommendations proves to be a challenge in this patient population. Additional studies of larger patient populations with longer follow up periods in similar settings may be helpful in informing appropriate patient selection and maximizing successful outcomes of corneal transplantation in low-resource settings.

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          Most cited references15

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          Revision of visual impairment definitions in the International Statistical Classification of Diseases

          Background The existing definitions of visual impairment in the International Statistical Classification of Diseases are based on recommendations made over 30 years ago. New data and knowledge related to visual impairment that have accumulated over this period suggest that these definitions need to be revised. Discussion Three major issues need to be addressed in the revision of these definitions. First, the existing definitions are based on best-corrected visual acuity, which exclude uncorrected refractive error as a cause of visual impairment, leading to substantial underestimation of the total visual impairment burden by about 38%. Second, the cut-off level of visual impairment to define blindness in the International Statistical Classification of Diseases is visual acuity less than 3/60 in the better eye, but with increasing human development the visual acuity requirements are also increasing, suggesting that a level less than 6/60 be used to define blindness. Third, the International Statistical Classification of Diseases uses the term 'low vision' for visual impairment level less than blindness, which causes confusion with the common use of this term for uncorrectable vision requiring aids or rehabilitation, suggesting that alternative terms such as moderate and mild visual impairment would be more appropriate for visual impairment less severe than blindness. We propose a revision of the definitions of visual impairment in the International Statistical Classification of Diseases that addresses these three issues. According to these revised definitions, the number of blind persons in the world defined as presenting visual acuity less than 6/60 in the better eye would be about 57 million as compared with the World Health Organization estimate of 37 million using the existing International Statistical Classification of Diseases definition of best-corrected visual acuity less than 3/60 in the better eye, and the number of persons in the world with moderate visual impairment defined as presenting visual acuity less than 6/18 to 6/60 in the better eye would be about 202 million as compared with the World Health Organization estimate of 124 million persons with low vision defined as best-corrected visual acuity less than 6/18 to 3/60 in the better eye. Conclusion Our suggested revision of the visual impairment definitions in the International Statistical Classification of Diseases takes into account advances in the understanding of visual impairment. This revised classification seems more appropriate for estimating and tracking visual impairment in the countries and regions of the world than the existing classification in the International Statistical Classification of Diseases.
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            Pediatric keratoconus: a review of the literature.

            To describe the epidemiology and prevalence, rates of progression, difference between adult and pediatric populations, and therapeutic approaches to pediatric keratoconus from documented literature.
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              Factors predictive of corneal graft survival. Report from the Australian Corneal Graft Registry.

              Risk factors for graft failure after penetrating keratoplasty were investigated in 961 patients from records collected prospectively by the Australian Corneal Graft Registry. The most common cause of graft failure was irreversible rejection. A multivariate proportional hazards regression analysis indicated that the key predictors of graft failure were: an indication for graft other than keratoconus or corneal dystrophy; a failed previous graft (ipsilateral eye); aphakia; inflammation at the time of graft; presence of an anterior chamber or iris-clip intraocular lens; graft size outside the range of 7.0 to 7.9 mm diameter; and corneal vascularization occurring in the postoperative period.
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                Author and article information

                Contributors
                Role: ConceptualizationRole: Data curationRole: Formal analysisRole: InvestigationRole: MethodologyRole: Project administrationRole: ResourcesRole: SupervisionRole: ValidationRole: Writing – original draftRole: Writing – review & editing
                Role: ConceptualizationRole: Data curationRole: Formal analysisRole: MethodologyRole: ValidationRole: VisualizationRole: Writing – original draftRole: Writing – review & editing
                Role: ConceptualizationRole: Data curationRole: Formal analysisRole: MethodologyRole: ValidationRole: VisualizationRole: Writing – original draftRole: Writing – review & editing
                Role: ConceptualizationRole: ResourcesRole: SupervisionRole: Writing – review & editing
                Role: ConceptualizationRole: Data curationRole: InvestigationRole: ResourcesRole: Writing – review & editing
                Role: Editor
                Journal
                PLoS One
                PLoS ONE
                plos
                plosone
                PLoS ONE
                Public Library of Science (San Francisco, CA USA )
                1932-6203
                27 October 2017
                2017
                : 12
                : 10
                : e0187026
                Affiliations
                [1 ] Penn State Eye Center, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
                [2 ] Tenwek Hospital, Bomet, Bomet County, Kenya
                [3 ] Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
                [4 ] Wills Eye Hospital, Philadelphia, Pennsylvania, United States of America
                London School of Hygiene & Tropical Medicine, UNITED STATES
                Author notes

                Competing Interests: The authors have declared no competing interests exist.

                Author information
                http://orcid.org/0000-0001-5178-4632
                Article
                PONE-D-17-18100
                10.1371/journal.pone.0187026
                5659646
                29077728
                571d2c8c-3e9e-4e89-ba1a-ca9a3f3a47f8
                © 2017 Chen et al

                This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

                History
                : 11 May 2017
                : 12 October 2017
                Page count
                Figures: 1, Tables: 4, Pages: 10
                Funding
                The authors received no specific funding for this work.
                Categories
                Research Article
                Medicine and Health Sciences
                Surgical and Invasive Medical Procedures
                Ophthalmic Procedures
                Corneal Transplantation
                Medicine and Health Sciences
                Surgical and Invasive Medical Procedures
                Transplantation
                Corneal Transplantation
                Biology and Life Sciences
                Anatomy
                Head
                Eyes
                Medicine and Health Sciences
                Anatomy
                Head
                Eyes
                Biology and Life Sciences
                Anatomy
                Ocular System
                Eyes
                Medicine and Health Sciences
                Anatomy
                Ocular System
                Eyes
                Medicine and Health Sciences
                Surgical and Invasive Medical Procedures
                Transplantation
                Graft Survival
                Medicine and Health Sciences
                Surgical and Invasive Medical Procedures
                Ophthalmic Procedures
                Keratoplasty
                Penetrating Keratoplasty
                Biology and Life Sciences
                Anatomy
                Ocular System
                Ocular Anatomy
                Cornea
                Medicine and Health Sciences
                Anatomy
                Ocular System
                Ocular Anatomy
                Cornea
                People and Places
                Geographical Locations
                Africa
                Kenya
                Medicine and Health Sciences
                Health Care
                Patients
                Biology and Life Sciences
                Neuroscience
                Sensory Perception
                Vision
                Visual Acuity
                Biology and Life Sciences
                Psychology
                Sensory Perception
                Vision
                Visual Acuity
                Social Sciences
                Psychology
                Sensory Perception
                Vision
                Visual Acuity
                Custom metadata
                All relevant data are within the paper and its Supporting Information files.

                Uncategorized
                Uncategorized

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