Smart contact lens: A promising therapeutic tool in aniridia.

OBJECTIVE: The perform pre-clinical testing using optical design tools to simulate the optical quality of a smart artificial iris platform encapsulated in a scleral contact lens. These tools allow us to generate aniridia eye models and evaluate different metrics of visual quality and retinal illumination based on the aperture of the artificial iris based on liquid crystals. METHOD: The OCT imaging technique was used to measure the geometry of the anterior segment in a patient with aniridia and, from these data, the eye model was generated with the Zemax optical design program and specific programs developed in Matlab. Ocular aberrations were calculated and the visual function of the anirida eye model was evaluated in three scenarios: (i) without optical correction, (ii) with correction with a commercial scleral contact lens, and (iii) with correction with an optical lens. Intelligent contact based on artificial iris. RESULTS: Optical quality in patients with aniridia is limited by the magnitude of high-order aberrations. Conventional scleral contact lens design accurately corrects for blur but is unable to compensate for high-order ocular aberrations, especially spherical aberrations. The artificial iris-based smart contact lens design enables virtually all high-order aberrations to be compensated with active control of the pupillary diameter (activation of liquid crystal cells based on ambient lighting). In addition to minimizing high-order aberrations, reducing the pupil size would increase the depth of focus. CONCLUSIONS: This article demonstrates by means of optical simulations the concept of an intelligent artificial iris platform encapsulated in a scleral contact lens and its possible application in patients with aniridia. Furthermore, it allows us to anticipate possible visual results in clinical trials with healthy patients (after application of mydriatic agents) and in patients with aniridia. The results demonstrate a better visual quality and a decrease in retinal illumination.

Smart contact lens: a promising therapeutic tool in aniridia. / Lente de contacto inteligente: una prometedora herramienta terapéutica en aniridia.

OBJECTIVE: To perform pre-clinical testing using optical design tools to simulate the optical quality of a smart artificial iris platform encapsulated in a scleral contact lens. These tools allow us to generate aniridia eye models and evaluate different metrics of visual quality and retinal illumination based on the aperture of the artificial iris based on liquid crystals. METHOD: The OCT imaging technique was used to measure the geometry of the anterior segment in a patient with aniridia and, from these data, the eye model was generated with the Zemax optical design program and specific programs developed in Matlab. Ocular aberrations were calculated and the visual function of the anirida eye model was evaluated in three scenarios: (i) without optical correction, (ii) with correction with a commercial scleral contact lens, and (iii) with correction with an optical lens. intelligent contact based on artificial iris. RESULTS: Optical quality in patients with aniridia is limited by the magnitude of high-order aberrations. Conventional scleral contact lens design accurately corrects for blur but is unable to compensate for high-order ocular aberrations, especially spherical aberrations. The artificial iris-based smart contact lens design enables virtually all high-order aberrations to be compensated with active control of the pupillary diameter (activation of liquid crystal cells based on ambient lighting). In addition to minimizing high-order aberrations, reducing the pupil size would increase the depth of focus. CONCLUSIONS: This article demonstrates by means of optical simulations the concept of an intelligent artificial iris platform encapsulated in a scleral contact lens and its possible application in patients with aniridia. Furthermore, it allows us to anticipate possible visual results in clinical trials with healthy patients (after application of mydriatic agents) and in patients with aniridia. The results demonstrate a better visual quality and a decrease in retinal illumination.

Comparación de las características corneales en gallina y codorniz como modelos experimentales de cirugía refractiva / Comparison of the characteristics in hen and quail corneas as experimental models of refractive surgery

OBJETIVO: Analizar y comparar la histología, la morfología y las medidas biofísicas corneales de la gallina y la codorniz para determinar qué modelo experimental animal es el más adecuado para la realización de estudios de investigación en cirugía corneal. MATERIAL Y MÉTODOS: Se estudiaron las medidas biofísicas de la córnea (curvatura, espesor, refracción y longitud axial) de 20 animales (10 gallinas y 10 codornices). Después las córneas fueron procesadas para el estudio de histología clásica bajo la luz del microscopio. RESULTADOS: Los 2 grupos analizados poseen una córnea similar a la del humano con respecto al número de capas y con una evidente capa de Bowman. El espesor corneal, así como la longitud axial del ojo de la gallina, 225,3 ± 18,4 μm y 12,8 ± 0,25 mm, respectivamente, fueron significativamente mayores que los de la codorniz (p < 0,01 y p < 0,001). El radio de curvatura de la córnea central de la gallina también fue significativamente mayor que el de la codorniz (p < 0,001). El poder refractivo de las 2 especies fue similar. La proporción del espesor estromal con relación a la córnea en la gallina fue más similar al humano (82,6%) que de la codorniz (72,5%). La densidad de la población de queratocitos en la gallina, 8,57 ± 1,49/5.000 μm2, correspondió a cerca de la mitad del número de queratocitos encontrados en la córnea de la codorniz (p < 0,005). CONCLUSIONES: La córnea de gallina, por su tamaño, espesor del estroma y similitud de proporción en sus capas con la córnea humana, es más adecuada para la cirugía refractiva corneal que la de codorniz

AIM: To compare the histological, morphological and the biophysical measurements between hen and quail corneas, in order to determine which of them were better suited for use as an animal model for research into corneal refractive surgery. MATERIAL AND METHODS: A study was performed using the biophysical measurements of the cornea (curvature, thickness, refraction, and axial length) of 20 animals (10 hens and 10 quails). The corneas were then prepared for histological analysis under microscopy light. RESULTS: The analysis showed that both groups have the same number of corneal layers as the human cornea and with an evident Bowman's layer. The thickness of the hen cornea and axial length of the eye, 225.3 ± 18.4 μm and 12.8 ± 0.25 mm, respectively, were larger than that of the quail (P < .01 andP < .001, respectively). The radius of curvature for the hen central cornea, 3.65 ± 0.08 mm, was greater than that for the quail (P < .001), but the refractive power of each cornea was similar. The proportion of total corneal thickness of the hen stroma, 82.6%, was more similar to that of the human than was the quail stroma, 72.5%. Within the hen stroma, the density of keratocytes, 8.57 ± 1.49 per 5,000 μm2, was about half that in the quail stroma (P < .005). CONCLUSIONS: Because of the large size of the hen cornea, the stromal thickness and proportional similarity of the corneal layers with human cornea, the hen maybe better than the quail as an alternative species suitable for use in studies of corneal refractive surgery

Full 3-D OCT-based pseudophakic custom computer eye model.

We compared measured wave aberrations in pseudophakic eyes implanted with aspheric intraocular lenses (IOLs) with simulated aberrations from numerical ray tracing on customized computer eye models, built using quantitative 3-D OCT-based patient-specific ocular geometry. Experimental and simulated aberrations show high correlation (R = 0.93; p<0.0001) and similarity (RMS for high order aberrations discrepancies within 23.58%). This study shows that full OCT-based pseudophakic custom computer eye models allow understanding the relative contribution of optical geometrical and surgically-related factors to image quality, and are an excellent tool for characterizing and improving cataract surgery.

Comparison of the characteristics in hen and quail corneas as experimental models of refractive surgery. / Comparación de las características corneales en gallina y codorniz como modelos experimentales de cirugía refractiva.

AIM: To compare the histological, morphological and the biophysical measurements between hen and quail corneas, in order to determine which of them were better suited for use as an animal model for research into corneal refractive surgery. MATERIAL AND METHODS: A study was performed using the biophysical measurements of the cornea (curvature, thickness, refraction, and axial length) of 20 animals (10 hens and 10 quails). The corneas were then prepared for histological analysis under microscopy light. RESULTS: The analysis showed that both groups have the same number of corneal layers as the human cornea and with an evident Bowman's layer. The thickness of the hen cornea and axial length of the eye, 225.3±18.4µm and 12.8±0.25mm, respectively, were larger than that of the quail (P<.01 and P<.001, respectively). The radius of curvature for the hen central cornea, 3.65±0.08mm, was greater than that for the quail (P<.001), but the refractive power of each cornea was similar. The proportion of total corneal thickness of the hen stroma, 82.6%, was more similar to that of the human than was the quail stroma, 72.5%. Within the hen stroma, the density of keratocytes, 8.57±1.49 per 5,000µm(2), was about half that in the quail stroma (P<.005). CONCLUSIONS: Because of the large size of the hen cornea, the stromal thickness and proportional similarity of the corneal layers with human cornea, the hen maybe better than the quail as an alternative species suitable for use in studies of corneal refractive surgery.

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery.

The objective of this work was to evaluate the potential use of less stiff materials based on acrylic copolymers of methyl methacrylate/2-ethylhexyl acrylate (MMA/EHA) as devices to correct, stabilize and improve the effect of poly(methyl methacrylate) (PMMA) intracorneal ring segments. MMA/EHA and PMMA intracorneal ring segments were surgically implanted in the corneas of Lohmann Classic hens. The effects of the intracorneal ring segments were assessed by optical measurements and corneal tolerance was evaluated through biomicroscopic examination over a 90-day observation period and by conventional histology. The experimental results demonstrated that the intracorneal ring segments made of MMA/EHA copolymers provided a significant change in the corneal curvature and an improved in vivo response compared to those obtained for PMMA rings, which was attributed to the higher flexibility of the copolymeric materials, indicating that these systems might be considered suitable as an alternative to those currently used, for application in clinical practice.