PURPOSE. To demonstrate that corneal light-backscatter can be measured object ively during corneal swelling by optical coherence tomography (OCT). METHODS. On e eye (randomly selected) of 20 non-contact-lens wearers (...PURPOSE. To demonstrate that corneal light-backscatter can be measured object ively during corneal swelling by optical coherence tomography (OCT). METHODS. On e eye (randomly selected) of 20 non-contact-lens wearers (10 men and 10 women; mean age, 35.6 ±9.6 years) was patched during 3 hours of soft contact lens (SC L) wear. The contralateral eye acted as the control. Central corneal images were captured before and after SCL wear at 20-minute intervals over 100 minutes usi ng optical coherence tomography (OCT) to obtain corneal thickness and light-bac kscatter profiles. OCT backscattered light of the epithelial layer (decided by t he thickness measurements) and 10 equally divided layers of the remaining cornea were analyzed with a custom soft ware program. Two baseline measurements were t aken at different visits before lens wear to test the repeatability of light-ba ckscatter measurements. RESULTS. From two baseline measurements, repeated measur ements showed good repeatability of normalized backscatter results. Immediately after contact lens removal, total central corneal thickness increased significan tly by 13.8%±2.3%(mean ±SD) compared with baseline (P=0.0001, paired t-test ) and then decreased during the deswelling course. Corneal backscattered light c hanged significantly (repeated-measures ANOVA Re-ANOVA: F(50,950)=2.22, P=0. 0001) after lens wear, and a significant increase in backscatter was found in th e epithelial layer (36.4%) and the most posterior corneal layer (35.6%) immedi ately after lens removal (post hoc test, P=0.005). There was a strong correlatio n (r=0.9375, P< 0.05) between the change in backscatter and corneal swelling dur ing the deswelling period. The backscatter recovery rate was approximately the s ame for both epithelial and posterior layers after lens removal. CONCLUSIONS. Li ght- backscattering analysis with OCT seems to be a promising and repeatable method of objectively measuring corneal backscatter. This study has demonstrated that corneal backscattered light increased in the anterior and posterior layers of th e cornea during corneal swelling induced by contact lens wear and eye closure.展开更多
Topical formulations, commonly applied for treatment of anterior eye diseases, require frequent administration due to rapid clearance from the ocular surface, typically through the lacrimal drainage system or through ...Topical formulations, commonly applied for treatment of anterior eye diseases, require frequent administration due to rapid clearance from the ocular surface, typically through the lacrimal drainage system or through over-spillage onto the lids. We report on a mucoadhesive nanoparticle drug delivery system that may be used to prolong the precorneal residence time of encapsulated drugs. The nanoparticles were formed from self-assembly of block copolymers composed of poly（D, L-lactide） and Dextran. The enhanced mucoadhesion properties were achieved by surface functionalizing the nanoparticles with phenylboronic acid. The nanoparticles encapsulated up to 12 wt.% of Cyclosporine A （CycA） and sustained the release for up to five days at a clinically relevant dose, which led us to explore the therapeutic efficacy of the formulation with reduced administration frequency. By administering CycA-loaded nanoparticles to dry eye-induced mice once a week, inflammatory infiltrates were eliminated and the ocular surface completely recovered. The same once a week dosage of the nanoparticles also showed no signs of physical irritation or inflammatory responses in acute （1 week） and chronic （12 weeks） studies in healthy rabbit eyes. These findings indicate that the nanoparticles may significantly reduce the frequency of administration for effective treatment of anterior eye diseases without causing ocular irritation.展开更多
文摘PURPOSE. To demonstrate that corneal light-backscatter can be measured object ively during corneal swelling by optical coherence tomography (OCT). METHODS. On e eye (randomly selected) of 20 non-contact-lens wearers (10 men and 10 women; mean age, 35.6 ±9.6 years) was patched during 3 hours of soft contact lens (SC L) wear. The contralateral eye acted as the control. Central corneal images were captured before and after SCL wear at 20-minute intervals over 100 minutes usi ng optical coherence tomography (OCT) to obtain corneal thickness and light-bac kscatter profiles. OCT backscattered light of the epithelial layer (decided by t he thickness measurements) and 10 equally divided layers of the remaining cornea were analyzed with a custom soft ware program. Two baseline measurements were t aken at different visits before lens wear to test the repeatability of light-ba ckscatter measurements. RESULTS. From two baseline measurements, repeated measur ements showed good repeatability of normalized backscatter results. Immediately after contact lens removal, total central corneal thickness increased significan tly by 13.8%±2.3%(mean ±SD) compared with baseline (P=0.0001, paired t-test ) and then decreased during the deswelling course. Corneal backscattered light c hanged significantly (repeated-measures ANOVA Re-ANOVA: F(50,950)=2.22, P=0. 0001) after lens wear, and a significant increase in backscatter was found in th e epithelial layer (36.4%) and the most posterior corneal layer (35.6%) immedi ately after lens removal (post hoc test, P=0.005). There was a strong correlatio n (r=0.9375, P< 0.05) between the change in backscatter and corneal swelling dur ing the deswelling period. The backscatter recovery rate was approximately the s ame for both epithelial and posterior layers after lens removal. CONCLUSIONS. Li ght- backscattering analysis with OCT seems to be a promising and repeatable method of objectively measuring corneal backscatter. This study has demonstrated that corneal backscattered light increased in the anterior and posterior layers of th e cornea during corneal swelling induced by contact lens wear and eye closure.
文摘Topical formulations, commonly applied for treatment of anterior eye diseases, require frequent administration due to rapid clearance from the ocular surface, typically through the lacrimal drainage system or through over-spillage onto the lids. We report on a mucoadhesive nanoparticle drug delivery system that may be used to prolong the precorneal residence time of encapsulated drugs. The nanoparticles were formed from self-assembly of block copolymers composed of poly（D, L-lactide） and Dextran. The enhanced mucoadhesion properties were achieved by surface functionalizing the nanoparticles with phenylboronic acid. The nanoparticles encapsulated up to 12 wt.% of Cyclosporine A （CycA） and sustained the release for up to five days at a clinically relevant dose, which led us to explore the therapeutic efficacy of the formulation with reduced administration frequency. By administering CycA-loaded nanoparticles to dry eye-induced mice once a week, inflammatory infiltrates were eliminated and the ocular surface completely recovered. The same once a week dosage of the nanoparticles also showed no signs of physical irritation or inflammatory responses in acute （1 week） and chronic （12 weeks） studies in healthy rabbit eyes. These findings indicate that the nanoparticles may significantly reduce the frequency of administration for effective treatment of anterior eye diseases without causing ocular irritation.
