Biocompatibility with the Ocular Surface and Antimicrobial Activity of a New Multi-Purpose Contact Lens Solution / Biocompatibilidad con la superficie ocular y actividad antimicrobiana de una nueva solución multipropósito para lentes de contacto / Biocompatibilidade com a superfície ocular e atividade antimicrobiana de uma nova solução de lentes de contato multipropósito

Abstract Introduction: Multipurpose solutions (MPS) for soft contact lenses (SCL) play an essential role in inhibiting potentially pathogenic agents. Their antimicrobial effectiveness is assessed in vitro and their safety in vivo, with clinical trials that include a combination of different solutions and lens materials. The objective is to assess the biocompatibility of a new SCL MPS produced in Colombia that contains polyhexamethylene biguanide (PHMB) and to determine its antimicrobial activity. Materials and Methods: This was a crossover study with 25 subjects who did not wear lens and who were fitted with different combinations of five SCL materials with either MPS or control physiological saline solution (CS). Corneal thickness, conjunctival hyperemia, corneal staining, and comfort were assessed after two hours of wearing SCL. Antimicrobial effectiveness was measured using ISO 14729 standard assays. Results: When considering SCL material, there was a statistically significant difference between the new MPS and the CS for Comfilcon A (p < 0.05). There was no statistical or clinically significant difference for corneal thickness or corneal staining between the combination of lens material and new MPS with the CS (p > 0.05). After two hours of lens insertion, comfort scores were higher than 7.8. The MPS reduced bacteria colony forming units (CFU) in over 3 log, and fungal CFU in over 1.0 log. Conclusions: The new MPS met the antimicrobial standards of ISO 14729, is considered safe and biocompatible with the ocular surface and retains high comfort levels.

Resumen Introducción: las soluciones multipropósito (SMP) para lentes de contacto blandos (LCB) desempeñan un papel esencial en la inhibición de agentes potencialmente patógenos. Su efectividad antimicrobiana se evalúa in vitro, y su seguridad, in vivo, con ensayos clínicos que incluyen una combinación de diferentes soluciones y materiales para lentes. El objetivo es evaluar la biocompatibilidad de una nueva SMP producida en Colombia que contiene polihexametileno biguanida (PHMB) y determinar su actividad antimicrobiana. Materiales y métodos: estudio cruzado con 25 sujetos no usuarios de lentes, que fueron adaptados con cinco combinaciones diferentes de materiales de LCB con una nueva SMP o solución salina fisiológica de control (CS). El grosor corneal, la hiperemia conjuntival, la tinción corneal y la comodidad se evaluaron después de dos horas de uso del LC. La efectividad antimicrobiana se midió utilizando ensayos estándar ISO 14729. Resultados: considerando el material del LCB, solo hubo una diferencia estadísticamente significativa entre la nueva SMP y el CS para el Comfilcon A (p < 0.05). Tampoco hubo diferencias estadísticamente o clínicamente significativas para el grosor corneal o la tinción corneal, entre la combinación del material del lente y la nueva SMP con el CS (p > 0.05). Después de dos horas de uso del lente, las puntuaciones de confort fueron superiores a 7.8. La SMP redujo las unidades formadoras de colonias (UFC) de bacterias en más de 3 log, y las UFC fúngicas en más de 1.0 log. Conclusiones: la nueva SMP cumplió con los estándares antimicrobianos de ISO 14729, y se considera segura y biocompatible con la superficie ocular, con altos niveles de confort.

Resumo Introdução: as soluções multipropósito (SMP) para lentes de contato macias (LCM) apresentam um papel essencial na inibição de agentes potencialmente patógenos. Sua eficácia como agente antimicrobiano se valia in vitro, e sua segurança, in vivo, como ensaios clínicos que incluem uma combinação de diferentes soluções e materiais para lentes. O objetivo é avaliar a biocompatibilidade de uma nova SMP produzida na Colômbia a base de polihexametileno biguanida (PHMB) e determinar seu potencial antimicrobiano. Materiais e métodos: estudo cruzado com 25 indivíduos não usuários de lentes, que foram adaptados com cinco combinações diferentes de LCM como uma nova SMP ou solução salina fisiológica como controle (CS). A espessura da córnea, a hiperemia conjuntival, a coloração da córnea e a comodidade, foram avaliadas após duas horas de uso da LCB. A eficácia antimicrobiana foi medida com ensaios padrão ISO 14729. Resultados: considerando o material da LCB, houve apenas uma diferença estatisticamente significativa entre a nova SMP e o CS, paro o Comfilcon A (p <0.05). Não houve diferença estatisticamente ou clinicamente significativa para a espessura da córnea ou a coloração da córnea, entre a combinação do material da lente e a nova SMP com o controle CS (p > 0.05). Após duas horas de uso, as pontuações de conforto foram superiores a 7,8. A SMP reduziu as unidades formadoras de colônias (UFC) de bactérias em mais de 3 log, e as UFC fúngicas em mais de 1.0 log. Conclusões: a nova SMP cumpriu com os padrões antimicrobianos ISO 14729, é considerada segura e biocompatível com a superfície ocular, com altos níveis de conforto.

Comparison of the effect of soft contact lens and rb-bFGF eye drops on promoting postoperative repair of deep corneal foreign body / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the repairment of wound by using soft contact lenses and rb-bFGF eye drops after deep foreign body removal.<p>METHODS: Patients with deep corneal foreign body(72 cases, 72 eyes)were randomly separated into three groups and received surgery to remove the foreign bodys. Patients in group C only accepted levofloxacin eye drops and ofloxacin eye ointment while patients in group A wore soft contact lenses and group B received rb-bFGF eye drops as an extra after operation. The corneal irritation and pain(1, 3, 5d), wound healing(1wk)and relevant factors in visual acuity impairment(1mo)were observed after deep foreign body removal.<p>RESULTS: Corneal irritation and pain scores in group A were significantly lower than that in the other two groups at 1, 3 and 5d after operation. Patients felt less painful in group B than group C at 3 and 5d. Corneal wound healing in groups A and B was significantly higher than group C at 1wk after surgery(<i>P</i>>0.05). The closer corneal foreign body was to the pupil area, the more vision was affected after 1mo operation(<i>r</i>s=0.635, <i>P</i><0.05).<p>CONCLUSION: Soft contact lenses can effectively alleviate eye irritation after deep corneal foreign body removal in early time. Both SCL and rb-bFGF eye drops can accelerate the recovery of corneal wounds. Visual acuity impairment was closely related to the location of foreign body in deep corneal.

Efficacy of highly hydrophilic soft contact lenses for persistent corneal epithelial defects after anterior segment surgery / 国际眼科杂志(Guoji Yanke Zazhi)

AlM:To investigate the efficacy of highly hydrophilic soft contact lenses for persistent corneal epithelial defects. METHODS: ln this retrospective case analysis, 28 patients ( 28 eyes ) with persistent corneal epithelial defects after anterior segment surgery from January 2011 to June 2013 in our hospital were reviewed. After regular treatment for at least 2wk, the persistent corneal epithelial defects were treated with highly hydrophilic soft contact lenses, until the corneal epithelial healing. Continued to wear the same lens no more than 3wk, or in need of replacement the new one. All cases were followed up for 6mo. Key indicators of corneal epithelial healling, corneal fluorescein staining and ocular symptoms improvement were observed.RESULTS: Twenty-one eyes were cured (75. 00%), markedly effective in 5 eyes (17. 86%) , effective in 2 eyes (7. 14%), no invalid cases, the total efficiency of 100. 00%. Ocular symptoms of 25 cases (89. 29%) relieved within 2d, the rest 3 cases (10. 71%) relieved within 1wk. The corneal epithelial of 6 cases ( 21. 43%) repaired in 3wk, 13 cases (46. 43%) in 6wk, 7 cases (25. 00%) in 9wk, 2 cases ( 7. 14%) over 12wk. There were no signs of secondary infection. And no evidence of recurrence in 6mo.CONCLUSlON: Highly hydrophilic soft contact lenses could repair persistent corneal epithelial defects after anterior segment surgery significantly, while quickly and effectively relieve a variety of ocular irritation.

Comparison and Investigation of the National Standards for Tinted Contact Lenses between Various Countries

PURPOSE: In this study we investigated the safety level of the national standard for tinted soft contact lenses by comparing the standards in various countries. METHODS: To evaluate the current guidelines for tinted soft contact lenses such as form and appearance, diameter, curvature radius, vertex power, cylindrical refractivity and cylindrical axis, luminous/ultraviolet ray (UV) transmittance, moisture content, oxygen permeability coefficient, extractables, elution test, cytotoxicity, sensitization, eye irritation test, acute systemic/subchronic/subacute toxicity, genotoxicity and biocompatibility safety test using rabbit eyes and sterility test. We compared the standards of International Organization for Standardization (ISO), Food and Drug Administration (FDA) of the United States, Ministry of Health, Labor and Welfare (MHLW) of Japan and Ministry of Food and Drug Safety (MFDS) of Korea. RESULTS: The guidelines for tinted soft contact lenses of ISO, FDA and MFDS are similar to soft contact lenses but MHLW of Japan classifies these lenses and sets specific guidelines. First, the oxygen permeability coefficient measured at 6mm from the center should be maintained over 80%. Also, coloring should not affect the oxygen permeability coefficient significantly. Regarding the physical (form and appearance, diameter, curvature radius, moisture content) and optical (vertex power, cylindrical refractivity and cylindrical axis, luminous/UV transmittance, oxygen permeability coefficient) characteristics, no differences were found between ISO and MFDS. However, several differences were found in chemical characteristics (extractables, elution test) and biological stability (cytotoxicity, sensitization, eye irritation test, acute systemic/subchronic/subacute toxicity test, genotoxicity, biocompatibility safety test using rabbit eyes, sterility test). For example, the elution test is required only by MFDS. CONCLUSIONS: The reinvestigation into the effectiveness of the elution test is needed and new evaluation measures including scanning electron microscopy and atomic force microscopy designed for tinted soft contact lenses to evaluate the size of the optical area, the location and roughness of the pigmented layer are required.

As lentes de contato gelatinosas de silicone-hidrogel e suas gerações: fronteiras entre a relevância clínica e mensagens de marketing / Soft disposable silicone-hydrogel contact lenses and its generations: boundaries between clinical relevance and marketing messages

Desde sua concepção, por Leonardo da Vinci há mais de 500 anos, as lentes de contato têm apresentado relevantes avanços tecnológicos, principalmente a partir do início do século passado. A permanente introdução de novos materiais e desenhos produziu, ao longo do tempo, a designação de ?gerações? de lentes de contato, de forma a facilitar sua classificação para o oftalmologista. Este artigo discute a real relevância e utilidade existentes neste tipo de classificação quanto à escolha da melhor opção terapêutica para a correção dos diversos vícios de refração na prática clínica.

Estudio in vitro de la capacidad de proliferación de candida albicans en diferentes materiales de lentes de contacto blandos / In vitro study about the proliferation of candida albicans in different material soft contact lenses

Debido a la creciente importancia que tiene el uso de lentes de contacto blandos para corregir ametropías a nivel mundial y en la población Colombiana, sumado a la capacidad de la levadura Candida albicans de producir enfermedades oculares por el uso de los mismos, llegando a ser uno de los principales agentes infecciosos, en este estudio se evaluó la capacidad de Candida albicans de proliferar en 5 diferentes materiales de lentes de contacto blandos hidrofílicos, tres de ellos de hidrogel (Alphafilcon A, Omafilcon A, Polymacon) y dos de hidrogel silicona (Balafilcon A y Lotrafilcon A). Se encontró que la levadura puede proliferar en el material Alphafilcon A en mayor proporción, y en menor grado en Omafilcon A y lotrafilcon A.

The use of soft contact lenses has an increasing importance to correct ametropias at world-wide leveland in the Colombian population, besides, the yeastCandida albicans has the ability to produce oculardiseases by using the lenses, which has become inone of the main infectious agents. The proliferationcapability of Candida albicans was evaluated in 5different hydrophilic soft contact lenses, three of themof hidrogel (Alphafilcon A, Omafilcon A, Polymacon)and two of hidrogel silicone (Lotrafilcon A andBalafilcon A). Yeast proliferates in the Alphafilcon Amaterial in greater proportion, and in smaller degreein Omafilcon A and Lotrafilcon A.

Intraocular Pressure Difference With and Without Soft Contact Lenses by Noncontact Tonometry

Noncontact tonometer is a convenient instrument for checking of intraocular pressure without corneal touch. We compared the IOP of 45 eyes in 24 patients with and without soft contact lenses. Two measurements were taken on each eye while the patients were wearing soft conbtact lenses by noncontact tonometry, and rechecked immediatly after the lenses were removed. There was no significant differance between two measurements(t-test, P>0.05).