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<i>In Vivo</i> Effects of Preservative-free and Preserved Prostaglandin Analogs: Mouse Ocular Surface Study
摘要： Purpose: Chronic use of topical hypotensive agents induces several side effects caused by preservatives. The purpose of this study was to evaluate the effects of prostaglandin analogs with varying concentrations of benzalkonium chloride (BAC), preservative-free (PF), and alternative preservatives on mouse corneal tissue. Methods: Thirty-five, 8- to 10-week-old female C57BL/6 mice (five mice for each group) were used for this study. To the control group, we applied normal saline, and to each drug-treated group we applied 0.02% BAC, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), travoprost 0.004% (with 0.001% polyquad) or tafluprost 0.0015% with/without 0.001% BAC, once a day (9 p.m.) for 4 weeks. Corneal fluorescein staining was evaluated in all groups. After harvest, the corneal tissues were embedded in paraffin and then Hematoxylin-Eosin stain was performed for histopathological examination. Immunofluorescence staining was done against TNF-α, IL-6, HLA DR, pJNK, and pAkt. Results: In corneal fluorescein staining, severe punctate epithelial keratitis was seen in the groups of 0.02% BAC, 0.02% BAC containing bimatoprost 0.01% and latanoprost 0.005%. The surface desquamation, irregular surface, loss of cell borders, anisocytosis and stromal shrinkage were observed in the groups of BAC-containing eye drops. Moreover, the groups treated with BAC-containing eye drops have high inflammatory markers, significantly decreased cell viability-related signal, pAkt, and higher apoptosis-inducing signal, pJNK, than the control group. On the other hand, travoprost 0.004% and PF tafluprost 0.0015% have less cellular morphologic changes, lower inflammation, and higher cellular viability than BAC-containing formulations. Conclusions: Corneal damage, increased inflammation and apoptosis and low cell viability were observed in BAC-containing groups. PF or alternatively preserved glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.
关键词： Pharmaceutical preservatives,Synthetic prostaglandins,Benzalkonium compounds,Cornea
更新于2025-09-04 15:30:14
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Impact of corneal cross-linking combined with photorefractive keratectomy on blurring strength
摘要： The aim of this study was to evaluate the impact of corneal cross-linking combined with photorefractive keratectomy (PRK) on blurring strength. A total of 63 patients with keratoconus were recruited for this study, and two study groups were formed according to the therapeutic intervention: corneal collagen cross-linking (CxL) group (33 patients) received corneal cross-linking according to the Dresden protocol, while the rest additionally received topography-guided photorefractive keratectomy (tCxL). The impact of surgical procedure on blurring strength was assessed by power vector analysis. Potential association between blurring strength and vision-specific quality of life was assessed using the National Eye Institute Visual Function Questionnaire (NEI-VFQ) 25 instrument. Blurring strength presented excellent correlation with NEI-VFQ scores both preoperatively and postoperatively (all P,0.01). Both groups demonstrated nonsignificant changes in best-corrected visual acuity; however, only the tCxL group had significant reduction in blurring strength (13.48+10.86 [preoperative], 4.26+7.99 [postoperative], P=0.042). Only the combined treatment (tCxL) resulted in significant reduction in blurring strength. Moreover, the excellent correlation of blurring strength with NEI-VFQ scores indicates its reliability as an index of self-reported quality of life in keratoconus, since it seems to address the nonsignificant changes in best-corrected visual acuity following CxL treatments that are conceived as subjective improvement by the patient.
关键词： blurring strength,keratoconus,tCxL,cornea crosslinking
更新于2025-09-04 15:30:14
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Analysis of the corneal endothelium in eyes of chickens using contact specular microscopy
摘要： The corneal endothelium is a single layer of polygonal cells essential for corneal transparency. The objective of this study was to assess the parameters corneal endothelial cells in healthy chickens of different ages using a contact specular microscopy. A total 36 eyes of 18 chickens were evaluated in this study. After the humane slaughter of birds and subconjunctival enucleation, the eye bulbs were arranged into three groups according to the age of the chickens. Group 1 consisted of bulbs eyes of 6 chickens with ages ranging from 1 to 3 months old. Group 2 consisted of ocular bulbs 6 chickens with ages ranging from 5 to 12 months old. Group 3 consisted of bulbs eyes of 6 chickens with ages ranging from 24 to 40 months old. The contact specular microscopy was easy to perform and provided data such as endothelial cell density, average cell area and cellular pleomorphism. The results obtained with a contact specular microscopy revealed that the aging causes a decrease in the density of the corneal endothelium healthy chickens. Similarly, increasing the average endothelial cell area as well as the pleomorphism occurs. The present work suggests that the parameters of corneal endothelium of healthy chickens present change with advancing age.
关键词： cornea,contact specular microscopy,Chickens,endothelium
更新于2025-09-04 15:30:14
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Organ- on -a- chip technologies that can transform ophthalmic drug discovery and disease modeling
摘要： Introduction: Disorders of the eye that lead to visual impairment are affecting millions of people worldwide. Nevertheless, for many of these disorders, there are still no effective treatment options available due to the lack of in vitro model systems that emulate the physiological in vivo structure and function of human eyes. Microphysiological organ-on-a-chip (OoC) technology represents a novel and powerful approach to overcome the limitations of conventional model systems and lead to a paradigm shift in ophthalmic research. Areas covered: This review provides an overview of the various tissues of interest in ophthalmology and summarizes existing model systems, including their applications and limitations. Additionally, novel OoC systems with applications in ophthalmology are described and the advantages of these systems compared to conventional models are highlighted. Expert opinion: The physiological relevance of the first ophthalmic OoC systems that mimic human ocular compartments, such as the cornea and retina, has been successfully demonstrated in recent years. There is a great potential for the application of these platforms for future pharmacological target identification, safety, and efficacy testing, as well as personalized medicine. Further improvements and the development of new systems are of upmost importance, especially to model complex disorders affecting several tissues.
关键词： ophthalmic model,microphysiological system,retina-on-a-chip,ocular model,Cornea-on-a-chip,in-vitro models,organ-on-a-chip
更新于2025-09-04 15:30:14
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A Comparative Study of Vertebrate Corneal Structure: The Evolution of a Refractive Lens
摘要： PURPOSE. Although corneal curvature plays an important role in determining the refractive power of the vertebrate eye, the mechanisms controlling corneal shape remain largely unknown. To address this question, we performed a comparative study of vertebrate corneal structure to identify potential evolutionarily based changes that correlate with the development of a corneal refractive lens. METHODS. Nonlinear optical (NLO) imaging of second-harmonic–generated (SHG) signals was used to image collagen and three-dimensionally reconstruct the lamellar organization in corneas from different vertebrate clades. RESULTS. Second-harmonic–generated images taken normal to the corneal surface showed that corneal collagen in all nonmammalian vertebrates was organized into sheets (?sh and amphibians) or ribbons (reptiles and birds) extending from limbus to limbus that were oriented nearly orthogonal (ranging from 77.78–88.28) to their neighbors. The slight angular offset (28–138) created a rotational pattern that continued throughout the full thickness in ?sh and amphibians and to the very posterior layers in reptiles and birds. Interactions between lamellae were limited to "sutural" ?bers in cartilaginous ?sh, and occasional lamellar branching in ?sh and amphibians. There was a marked increase in lamellar branching in higher vertebrates, such that birds (cid:2) reptiles > amphibians > ?sh. By contrast, mammalian corneas showed a nearly random collagen ?ber organization with no orthogonal, chiral pattern. CONCLUSIONS. Our data indicate that nonmammalian vertebrate corneas share a common orthogonal collagen structural organization that shows increased lamellar branching in higher vertebrate species. Importantly, mammalian corneas showed a different structural organization, suggesting a divergent evolutionary background.
关键词： stroma,nonlinear optical,collagen,cornea,second-harmonic generation
更新于2025-09-04 15:30:14
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Application of In Vivo Confocal Microscopy in Dry Eye Disease
摘要： Confocal microscopy is a new, emerging, noninvasive technology that can aid in the in vivo assessment of structural changes in several ocular surface diseases at the cellular level. In the dry eye field, in vivo confocal microscopy has been applied to the examination of the cornea, bulbar and palpebral conjunctiva, Meibomian gland, and lacrimal gland. The device can assess the morphology, including superficial/wing/basal epithelial cell density, stromal keratocyte density, endothelial cell density, nerve fiber density, the number of beadings, nerve tortuosity, nerve reflectivity, and inflammatory cell density in the cornea. Furthermore, the device can not only assess epithelial cell density and area, goblet cell, microcyst, and inflammatory cell density but also the cellular architecture, including nucleocytoplasmic ratio in conjunctiva. The device also can disclose acinar unit density, acinar unit longest diameter, acinar unit shortest diameter, and inflammatory cell density in the Meibomian gland and lacrimal gland by other potential applications. Relevant research in Europe and the United States focused on the morphologic changes in the cornea in the dry eye field, while Japanese research focused on the conjunctival, Meibomian gland, and lacrimal gland alterations. The application of in vivo confocal microscopy in dry eye disease will be a powerful method to evaluate the morphologic change of the ocular surface around the world in the future.
关键词： dry eye,conjunctiva,Meibomian gland,confocal microscopy,lacrimal gland,cornea
更新于2025-09-04 15:30:14