Efectividad de la insulina tópica en el tratamiento de patologías de la superficie corneal / Effectiveness of topical insulin for the treatment of surface corneal pathologies

El propósito es identificar a través de una revisión sistemática de la literatura, la evidencia actual frente a la eficacia del tratamiento de la insulina tópica en patologías de la superficie ocular. Se implementó una búsqueda de literatura en bases de datos de indexación médica Medline (Pubmed), Embase y Web Of Science a través de palabras claves como «insulin» AND «córnea» OR «corneal» OR «dry eye» artículos publicados en inglés o español en los últimos once años (2011-2022). Se identificaron nueve artículos con 180 participantes provenientes de Estados Unidos, España, Irlanda, Canadá, Portugal y Malasia, con defectos epiteliales persistentes refractarios y secundarios a vitrectomía, cuya extensión de la lesión fue de 3,75 mm2 hasta 65,47 mm2. La preparación fue disuelta con lágrimas artificiales y la concentración de insulina fue desde 1 UI/ml hasta 100 UI/ml. En todos los casos la resolución del cuadro clínico fue completa con un tiempo de curación desde 2,5 días hasta 60,9 días siendo este último un caso secundario a una quemadura por cáusticos de difícil control. La insulina tópica ha sido efectiva para el tratamiento de defectos epiteliales persistentes; la de acción intermedia y en bajas concentraciones demostró menor tiempo de resolución, en úlceras neurotróficas y secundarias a vitrectomías (AU)

The purpose is to identify, through a systematic literature review, the current evidence regarding the effectiveness of topical insulin treatment in ocular surface pathologies. A literature search was implemented in Medline (Pubmed), Embase and Web Of Science medical indexing databases by using keywords such as “insulin” AND “cornea” OR “corneal” OR “dry eye” in published papers in English or Spanish within the last eleven years (2011-2022). Nine papers were identified with 180 participants from the United States, Spain, Ireland, Canada, Portugal and Malaysia, with persistent refractory epithelial defects and secondary to vitrectomy, whose extension of the lesion was from 3.75 mm2 to 65.47 mm2. The preparation was dissolved with artificial tears and the insulin concentration ranged from 1 IU/ml to 100 IU/ml. In all cases, the resolution of the clinical picture was complete with a healing time from 2.5 days to 60.9 days, the latter being a secondary case to a difficult-to-control caustic burn. Topical insulin has been effective for the treatment of persistent epithelial defects. The intermediate action and low concentrations showed a shorter resolution time in neurotrophic ulcers and induced during vitreoretinal surgery (AU)

Effectiveness of topical insulin for the treatment of surface corneal pathologies.

The Purpose is to identify, through a systematic literature review, the current evidence regarding the effectiveness of topical insulin treatment in ocular surface pathologies. A literature search was implemented in Medline (Pubmed), Embase and Web Of Science medical indexing databases by using keywords such as "insulin" AND "cornea" OR "corneal" OR "dry eye" in published papers in English or Spanish within the last eleven years (2011-2022). Nine papers were identified with 180 participants from the United States, Spain, Ireland, Canada, Portugal and Malaysia, with persistent refractory epithelial defects and secondary to vitrectomy, whose extension of the lesion was from 3,75mm2 to 65.47mm2. The preparation was dissolved with artificial tears and the insulin concentration ranged from 1 IU/ml to 100 IU/ml. In all cases, the resolution of the clinical picture was complete with a healing time from 2.5 days to 60.9 days, the latter being a secondary case to a difficult-to-control caustic burn. Topical insulin has been effective for the treatment of persistent epithelial defects. The intermediate action and low concentrations showed a shorter resolution time in neurotrophic ulcers and induced during vitreoretinal surgery.

Corneal epithelial thickness one year after myopic LASIK surgery, measured by anterior segment optical coherence tomography combined with Placido disk. / Grosor epitelial corneal un año después de la cirugía de LASIK miópico, medido mediante tomografía de coherencia óptica de segmento anterior combinado con disco de Plácido.

OBJECTIVE: To compare corneal epithelial thickness (CET) between patients who underwent LASIK surgery for the correction of myopia at least one year ago and healthy subjects. METHODS: A retrospective observational study was conducted that included 93 healthy subjects (186eyes) and 26 subjects (52eyes) that underwent myopic LASIK surgery. OCT-SA, combined with Placido disk, was performed on all subjects, and CET maps were measured. Statistical analysis was performed to analyse differences between groups. Multivariate analysis was also performed to look for possible predictors of final CET. RESULTS: There was no statistically significant differences between the groups in the demographic (age, sex) or anterior segment parameters (spherical equivalent, pachymetry) (all P>.05). Statistically significant differences (P<.05) were obtained between both groups when comparing CET, including central, internal, and external rings (higher in patients that underwent LASIK surgery ≥1year). With the exception of the time elapsed since surgery (P=.00), no correlation was found between the CET and age, sex, ablated dioptres, or other variables studied (P<.05). CONCLUSIONS: CET values measured by the OCT-SA were higher in patients that underwent LASIK surgery ≥1year. The only variable that correlated with the CET after LASIK was the time elapsed since surgery. CET changes should be taken into consideration when planning refractive surgery due to its implications on the final outcome.

Variations in the technique for autologous limbal transplantation. / Variaciones en la técnica del trasplante limbar autólogo.

OBJECTIVE: To present the results on the use of a single block limbal autograft, combined with amniotic membrane transplantation and sectoral sequential postoperative epitheliectomy of the conjunctiva in 2 patients with unilateral total limbal stem cell deficiency. CONCLUSIONS: A single block limbal autograft combined with amniotic membrane transplantation may be sufficient to restore a stable corneal surface, but sometimes sequential sectoral conjunctival epitheliectomy may be required to treat anomalous epithelial remnants.

Características in vivo del epitelio corneal versus magnitud del defecto refractivo, posterior a tratamiento con láser de excímeros / In vivo characteristics of the corneal epithelium vs size of the refractive error after Excimer laser treatment

Objetivo: describir las características in vivo del epitelio corneal y su relación con la magnitud del defecto refractivo tratado posterior al tratamiento quirúrgico de LASIK. Método: estudio descriptivo, prospectivo-longitudinal con 24 pacientes 48 ojos con astigmatismo miópico intervenidos con el ESIRIS Schwind-Alemania por la técnica quirúrgica LASIK con microquerátomo pendular. Se analizaron los resultados a partir de técnicas de estadística descriptiva. Se utilizó el microscopio confocal ConfoScan 4 de NIDEK para la obtención y estudio de las imágenes in vivo de tejido corneal. Resultados: el grosor epitelial central medio en el preoperatorio fue 34,7 mm, a los 7 días del posoperatorio hubo un incremento del 36 por ciento en pacientes con defectos refractivos inferiores a 4D y un incremento del 44 por ciento en pacientes con defectos refractivos de 4 D o más. El promedio de densidad de células del epitelio basal a los 7 días fue de 5 098,3±1 654 células/mm², tuvo variaciones mínimas inferiores a la unidad porcentual durante la etapa de estudio. Conclusiones: existió incremento del grosor epitelial posterior a LASIK que fue superior en defectos refractivos mayores de 4 dioptrías. La densidad celular del epitelio basal no tuvo variaciones significativas y fue independiente a la magnitud del defecto refractivo tratado(AU)

Objective: to describe the in vivo characteristics of the corneal epithelium and their association with the size of the treated refractive defect after LASIK. Methods: a prospective, longitudinal and descriptive study of 24 patients (48 eyes) with myopic astigmatism, who were operated on by using ESIRIS (Schwind-Germany) and LASIK technique with pendular microketatome. Summary statistic techniques served to analyze results. NIDEK´s ConfoScan 4 microscope was used to obtain and to study in vivo corneal tissue images. Results: mean central epithelial thickness measured in the preoperative stage was 34.7 mm, but increased by 36 percent seven days after surgery in patients with refractive defects fewer than 4D and by 44 percent in patients with refractive defects equal to or over 4D. The average cell density of the basal epithelium 7 days postoperatively was 5 098.3±1 654 cell/mm² and showed minimal changes below 1 percent during the study period. Conclusions: the central corneal epithelium thickness increased after LASIK surgery and it was higher in refractive defects over 4D. Cell density of the basal epithelium did not show significant changes and was not associated to the size of the treated refractive defect(AU)

Características in vivo del epitelio corneal versus magnitud del defecto refractivo, posterior a tratamiento con láser de excímeros / In vivo characteristics of the corneal epithelium vs size of the refractive error after Excimer laser treatment

Objetivo: describir las características in vivo del epitelio corneal y su relación con la magnitud del defecto refractivo tratado posterior al tratamiento quirúrgico de LASIK. Método: estudio descriptivo, prospectivo-longitudinal con 24 pacientes 48 ojos con astigmatismo miópico intervenidos con el ESIRIS Schwind-Alemania por la técnica quirúrgica LASIK con microquerátomo pendular. Se analizaron los resultados a partir de técnicas de estadística descriptiva. Se utilizó el microscopio confocal ConfoScan 4 de NIDEK para la obtención y estudio de las imágenes in vivo de tejido corneal. Resultados: el grosor epitelial central medio en el preoperatorio fue 34,7 mm, a los 7 días del posoperatorio hubo un incremento del 36 por ciento en pacientes con defectos refractivos inferiores a 4D y un incremento del 44 por ciento en pacientes con defectos refractivos de 4 D o más. El promedio de densidad de células del epitelio basal a los 7 días fue de 5 098,3±1 654 células/mm², tuvo variaciones mínimas inferiores a la unidad porcentual durante la etapa de estudio. Conclusiones: existió incremento del grosor epitelial posterior a LASIK que fue superior en defectos refractivos mayores de 4 dioptrías. La densidad celular del epitelio basal no tuvo variaciones significativas y fue independiente a la magnitud del defecto refractivo tratado

Objective: to describe the in vivo characteristics of the corneal epithelium and their association with the size of the treated refractive defect after LASIK. Methods: a prospective, longitudinal and descriptive study of 24 patients (48 eyes) with myopic astigmatism, who were operated on by using ESIRIS (Schwind-Germany) and LASIK technique with pendular microketatome. Summary statistic techniques served to analyze results. NIDEK´s ConfoScan 4 microscope was used to obtain and to study in vivo corneal tissue images. Results: mean central epithelial thickness measured in the preoperative stage was 34.7 mm, but increased by 36 percent seven days after surgery in patients with refractive defects fewer than 4D and by 44 percent in patients with refractive defects equal to or over 4D. The average cell density of the basal epithelium 7 days postoperatively was 5 098.3±1 654 cell/mm² and showed minimal changes below 1 percent during the study period. Conclusions: the central corneal epithelium thickness increased after LASIK surgery and it was higher in refractive defects over 4D. Cell density of the basal epithelium did not show significant changes and was not associated to the size of the treated refractive defect

Síndrome de Insuficiencia Limbal / Limbal Deficiency Syndrome

La córnea, el tejido transparente del ojo, está formada por un epitelio de cinco capas diferenciadas que está en continua renovación mediante una población de células madre limbocornéales ubicadas en su capa basal. Su actividad normal depende de una variedad de factores intrínsecos y extrínsecos, que de alterarse, pueden llevar a la pérdida parcial o total de las células progenitoras provocando la pérdida progresiva de la visión. Esta revisión pone de manifiesto la importancia de esta patología invalidante, constituyendo un gran problema de salud. Para tratarla se han desarrollado varias técnicas, siendo la más usada, históricamente, el trasplante de limbo mediante autoinjerto o aloinjerto acompañado de un tratamiento para inhibir la inflamación y la neovascularización. En la actualidad este procedimiento está siendo sustituido por las nuevas técnicas de ingeniería de tejidos, que tienen múltiples ventajas, como más seguridad, eficacia, eliminación de los riesgos de rechazo, disminución del tiempo de tratamiento y reducción de los costos. Usar las células limbales en cultivo ha hecho posible desarrollar técnicas cada vez más perfeccionadas y seguras, por lo que en la presente revisión se enfatiza en una de estas técnicas, la cual ha probado ser eficaz y ventajosa para obtener el epitelio de la córnea in vitro.

The cornea, the transparent tissue of the eye, is formed by an epithelium of five distinct layers that is in continual renewal through a population of limbocorneal stem cells located in the basal layer. Its normal activity depends on a variety of intrinsic and extrinsic factors, that altered, can lead to partial or total loss of progenitor cells leading to a progressive loss of vision. This article reviews the importance of this crippling disease, constituting a major health problem. Several techniques have been developed, but the transplant of the limbus using autograft or allograft accompanied by a treatment to suppress inflammation and neovascularization is still the most widely used. At present, this procedure is being replaced by the new techniques of tissue engineering, which have multiple benefits, such as more safety, efficiency, elimination of the risks of rejection, decrease of time of treatment and lower costs. The use of limbal cells cultures has made possible to develop a more secure and refined technology. In this review we emphasize one of these techniques, which has proven to be very effective and advantageous to produce the epithelium of the cornea in vitro.