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Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method.

Gonzalez-Andrades M, Cardona Jde L, Ionescu AM, Mosse CA, Brown RA - PLoS ONE (2015)

Bottom Line: All the samples used for optical evaluation by PBM or IAD were histological suitable.PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD.TR and BI obtained from the PBM showed a high correlation (ρ>/0.6/) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005).

View Article: PubMed Central - PubMed

Affiliation: Tissue Repair & Engineering Centre, University College of London, London, United Kingdom.

ABSTRACT

Purpose: Tissues and biomaterials used for corneal surface repair require fulfilling specific optical standards prior to implantation in the patient. However, there is not a feasible evaluation method to be applied in clinical or Good Manufacturing Practice settings. In this study, we describe and assess an innovative easy-applied photographic-based method (PBM) for measuring functional optical blurring and transparency in corneal surface grafts.

Methods: Plastic compressed collagen scaffolds (PCCS) and multilayered amniotic membranes (AM) samples were optically and histologically evaluated. Transparency and image blurring measures were obtained by PBM, analyzing photographic images of a standardized band pattern taken through the samples. These measures were compared and correlated to those obtained applying the Inverse Adding-Doubling (IAD) technique, which is the gold standard method.

Results: All the samples used for optical evaluation by PBM or IAD were histological suitable. PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD. The PBM indicated that PCCS had a transparency ratio (TR) value of 80.3 ± 2.8%, with a blurring index (BI) of 50.6 ± 4.2%. TR and BI obtained from the PBM showed a high correlation (ρ>/0.6/) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005). The AM optical properties showed that there was a largely linear relationship between the blurring and the number of amnion layers, with more layers producing greater blurring.

Conclusions: This innovative proposed method represents an easy-applied technique for evaluating transparency and blurriness of tissues and biomaterials used for corneal surface repair.

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Related in: MedlinePlus

Schematic representation of the experimental setup for performing the IAD technique.A-C: Configuration for Reflection measurements. D-F: Configuration for Transmission measurements (* represents the entrance port for each measurement).
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pone.0142099.g003: Schematic representation of the experimental setup for performing the IAD technique.A-C: Configuration for Reflection measurements. D-F: Configuration for Transmission measurements (* represents the entrance port for each measurement).

Mentions: Fig 3 shows a schematic of the experimental setup for measuring the total diffuse reflectance and total diffuse transmittance. In order to prevent oversaturation of the detector (53–2754 Model, Coherent, USA) intensity of the incident laser beams using a neutral density filters. The signal from the detector was measured by a digital multimeter (34401A Model, Agilent Technologies, USA). Three reflection measurements were made on each sample, recording 50 data points each time, referenced to a 98% Optopolymer reflectance standard (OPST3-C, Optopolymer, Germany). Dark measurements where made with the sample port open. The PCCS was placed between glass plates to prevent dehydration and provide mechanical support whilst minimizing surface effects[27]. Reference sphere calibration measurements were also made and the reflectance of the sphere wall was determined[26], taking into account all the geometric properties of the sphere known (wall area, sample area and other aperture areas).


Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method.

Gonzalez-Andrades M, Cardona Jde L, Ionescu AM, Mosse CA, Brown RA - PLoS ONE (2015)

Schematic representation of the experimental setup for performing the IAD technique.A-C: Configuration for Reflection measurements. D-F: Configuration for Transmission measurements (* represents the entrance port for each measurement).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643926&req=5

pone.0142099.g003: Schematic representation of the experimental setup for performing the IAD technique.A-C: Configuration for Reflection measurements. D-F: Configuration for Transmission measurements (* represents the entrance port for each measurement).
Mentions: Fig 3 shows a schematic of the experimental setup for measuring the total diffuse reflectance and total diffuse transmittance. In order to prevent oversaturation of the detector (53–2754 Model, Coherent, USA) intensity of the incident laser beams using a neutral density filters. The signal from the detector was measured by a digital multimeter (34401A Model, Agilent Technologies, USA). Three reflection measurements were made on each sample, recording 50 data points each time, referenced to a 98% Optopolymer reflectance standard (OPST3-C, Optopolymer, Germany). Dark measurements where made with the sample port open. The PCCS was placed between glass plates to prevent dehydration and provide mechanical support whilst minimizing surface effects[27]. Reference sphere calibration measurements were also made and the reflectance of the sphere wall was determined[26], taking into account all the geometric properties of the sphere known (wall area, sample area and other aperture areas).

Bottom Line: All the samples used for optical evaluation by PBM or IAD were histological suitable.PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD.TR and BI obtained from the PBM showed a high correlation (ρ>/0.6/) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005).

View Article: PubMed Central - PubMed

Affiliation: Tissue Repair & Engineering Centre, University College of London, London, United Kingdom.

ABSTRACT

Purpose: Tissues and biomaterials used for corneal surface repair require fulfilling specific optical standards prior to implantation in the patient. However, there is not a feasible evaluation method to be applied in clinical or Good Manufacturing Practice settings. In this study, we describe and assess an innovative easy-applied photographic-based method (PBM) for measuring functional optical blurring and transparency in corneal surface grafts.

Methods: Plastic compressed collagen scaffolds (PCCS) and multilayered amniotic membranes (AM) samples were optically and histologically evaluated. Transparency and image blurring measures were obtained by PBM, analyzing photographic images of a standardized band pattern taken through the samples. These measures were compared and correlated to those obtained applying the Inverse Adding-Doubling (IAD) technique, which is the gold standard method.

Results: All the samples used for optical evaluation by PBM or IAD were histological suitable. PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD. The PBM indicated that PCCS had a transparency ratio (TR) value of 80.3 ± 2.8%, with a blurring index (BI) of 50.6 ± 4.2%. TR and BI obtained from the PBM showed a high correlation (ρ>/0.6/) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005). The AM optical properties showed that there was a largely linear relationship between the blurring and the number of amnion layers, with more layers producing greater blurring.

Conclusions: This innovative proposed method represents an easy-applied technique for evaluating transparency and blurriness of tissues and biomaterials used for corneal surface repair.

Show MeSH
Related in: MedlinePlus