Phenol Red Thread Research Articles

Preclinical Efficacy Comparison of Cyclosporine Ophthalmic Solution 0.09% vs Cyclosporine Ophthalmic Emulsion 0.05% vs Ciclosporin Ophthalmic Emulsion 0.1% in a NOD Mouse Model of Dry Eye Disease.

IntroductionCyclosporine ophthalmic solution 0.09% (CsA 0.09% sol) is approved to increase tear production in patients with keratoconjunctivitis sicca. This study evaluated the efficacy of CsA 0.09% sol vs cyclosporine ophthalmic emulsion 0.05% (CsA 0.05% eml) vs ciclosporin ophthalmic emulsion 0.1% (CsA 0.1% eml) in a NOD mice model.MethodsMice were randomized and administered placebo, CsA 0.09% sol twice daily, CsA 0.05% eml twice daily, CsA 0.09% sol once daily, or CsA 0.1% eml once daily in the conjunctival sac of both eyes for 60 days. Tear volume was measured with phenol red threads at baseline and 4 hours after treatment every 15 days. On day 58, the corneal surface was observed under a slit-lamp after staining with 3% lissamine green administered into the inferior lateral conjunctival sac. On day 61, mice were euthanized, globes excised, sliced into 4 µm sections in 3 areas per section, and stained. Total number of stained goblet cell/µm was counted, and the sum per eye was averaged. Lacrimal gland tissues were removed and interleukin (IL) 1-β cytokine levels estimated.ResultsGroups comprised 11 mice each, including an untreated normal and untreated diseased control group (7 groups total). CsA 0.09% sol twice daily significantly increased tear volume on day 30, 45, and 60 vs CsA 0.05% eml (P<0.05, <0.001, <0.001, respectively) and vs CsA 0.1% eml on day 60 (P<0.05); CsA 0.09% sol once daily significantly increased tear volume on day 45 vs CsA 0.05% eml (P<0.05). Goblet cell density significantly increased with CsA 0.09% sol twice daily vs placebo and NOD control (P<0.01 both). There was no significant difference in corneal staining and IL-1β levels with CsA 0.09% sol.ConclusionSixty-day treatment with CsA 0.09% sol showed comparatively improved preclinical results vs CsA 0.05% eml and CsA 0.1% eml.

PEDF Attenuates Ocular Surface Damage in Diabetic Mice Model Through Its Antioxidant Properties

ABSTRACT Purpose To investigate the antioxidative effect and mechanism of pigment epithelium-derived factor (PEDF) on the ocular surface damage in diabetic mice. Methods C57BL/6 mice were injected intraperitoneally with streptozocin to generate diabetic models and then 50 nM PEDF or artificial tears were used to treat the diabetic mice. Treatment was given three times a day for eight weeks. Corneal epithelial damage, corneal sensitivity, and tear volume were quantified by fluorescein staining, esthesiometer, and phenol red cotton thread, respectively. Animals were sacrificed at 16 weeks after diabetes and the whole globe specimens were subjected to histochemical staining. Reactive oxygen species (ROS) generation was detected by 2ʹ,7-dichlorodihydrofluorescein probe. The levels of receptor for advanced glycation end products (RAGE) and superoxide dismutase 1 (SOD1) were examined by quantitative real-time PCR and western blotting. Results Topical application of PEDF improved corneal epithelial damage, increased corneal sensitivity, and tear volume in diabetic mice. ROS levels in the cornea were significantly higher in the diabetic mice than in the normal mice. Moreover, PEDF attenuated the accumulation of ROS, decreased the expression of RAGE, and elevated SOD1 expression in the cornea. Conclusions Topical application of PEDF can alleviate diabetes-related ocular surface damage and increase tear volume, along with the improvement of oxidative stress status.

NLRP12- and NLRC4-mediated corneal epithelial pyroptosis is driven by GSDMD cleavage accompanied by IL-33 processing in dry eye

PurposeDry eye disease (DED) is a common and multifactor-induced autoimmune ocular surface disease. Environmental factors, such as desiccating stress (DS) and hyperosmolarity, affect the corneal epithelium to induce ocular surface inflammation in DED. We aimed to explore the potential mechanisms by which innate immunity and pyroptosis are initiated in the mucosal epithelium in response to environmental stress. MethodsExperimental dry eye was established in C57BL/6 J mice and genetic mice on the background of C57BL/6 J mice by subcutaneous injection of scopolamine and exposure to a desiccating environment. SDHCEC cell line was subjected to hyperosmolarity stress (450 mOsM). The phenol red thread tear test and corneal epithelial defects evaluation were used as assessments of severity of DED. RNA-sequencing, quantitative real-time PCR, western blotting and immunofluorescence staining were performed in this study. ResultsLoss-of-function studies indicated that genetic deletion of GSDMD alleviates DS-induced corneal epithelium defects, and GSDMD is needed for IL-33 processing. We further found that NLRP12 collaborates with NLRC4 inflammasome to initiate GSDMD-dependent pyroptosis, which requires TLR4-induced caspase-8 (CASP8) activation in the mucosal corneal epithelium in response to DS. ConclusionsThese findings provide compelling evidence that GSDMD-dependent pyroptosis plays a pivotal role in DED. A novel mechanism involving NLRP12 and NLRC4 inflammasomes-induced GSDMD-dependent pyroptosis, accompanied by IL-33 processing is responsible for ocular surface epithelial defects in response to environmental stress. GSDMD is required for IL-33 processing and the subsequent amplification of inflammatory cascades. These findings reveal novel therapeutic targets for treating DED.

Environmental relative humidity affects Schirmer tear test results in normal dogs.

To investigate the effects of environmental temperature and relative humidity on tear test results in dogs. 22 normal dogs. Routine Schirmer tear tests (STT1) and phenol red thread tests (PRTT) were administered to normal dogs in four environmental conditions with different relative humidity (RH) and temperature (T). Environmental conditions (mean±SD) included the following: normal indoor (RH=49±4%, T=72±2°F), outdoor (RH=62±11%, T=85±6°F), indoor high humidity (RH=85±6%, T=71±1°F), and indoor low humidity (RH=39±2%, T=76±1°F). ANCOVA models were used to assess for significant associations between tear test readings and RH/T (P<.05). A significant, direct positive relationship between RH and STT1 results was detected (y=0.04909*X+19.11, P=.006) but not between T and STT1. There was no significant relationship between PRTT and RH or T. These results suggest that STT1 but not PRTT is affected by RH and that T does not influence STT1 or PRTT results in normal dogs. RH is unlikely, however, to cause clinically significant effects on STT1 readings in normal dogs when performed in average indoor conditions. Future studies should investigate the influence of RH on STT1 readings obtained in dogs with keratoconjunctivitis sicca.

Effects of Oral Antihistamines on Tear Volume, Tear Stability, and Intraocular Pressure.

The goal of this study was to investigate the effects of two commonly used oral antihistamines—diphenhydramine and loratadine—on tear volume, tear breakup time, and intraocular pressure. Placebo, diphenhydramine, and loratadine were administered for one week to 33 subjects experimentally blind to the treatment given. All the subjects received all three treatments over a period of six weeks. The outcome measures were the change in phenol red thread test (PRT), the tear breakup time (TBUT), and the intraocular pressure (IOP) of both eyes evaluated by experimentally masked observers. Neither of the mean changes in TBUT or IOP depended on the treatment given, but there was a significant monocular decrease in tear volume from diphenhydramine use. While we used an adequate treatment washout period of seven days, our investigation was limited by the short treatment times and inclusion of only young healthy patients. Overall, however, these results suggest that systemic diphenhydramine use should be limited to increase the effectiveness of conventional therapies. Clinicians should have fewer reservations about recommending the use of loratadine concurrent with dry eye treatments.

PPARγ: the dominant regulator among PPARs in dry eye lacrimal gland and diabetic lacrimal gland.

To investigate the regulatory roles of the members of the peroxisome proliferator-activated receptor (PPAR) family in lacrimal gland dysfunction under conditions of desiccating stress or diabetes. Quantitative polymerase chain reaction (qPCR) was used to examine the expression of PPARs in the cornea, conjunctiva, meibomian gland, and lacrimal gland in adult rats. The rats were divided into 3 groups: a control group, dry eye group, and diabetic group. The phenol red threads test, tear film break-up time (BUT) test and fluorescein staining were carried out to evaluate the development of dry eye. Based on bioinformatics research, qPCR was used to examine the expression level of PPARγ, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), sirtuin 1 (Sirt1), myeloid differentiation factor 88 (MyD88) and transforming growth factor-β (TGF-β) in the lacrimal glands. PPARα and PPARβ/δ were mainly expressed in the conjunctiva and the lacrimal gland, respectively. However, PPARγ was expressed in both the conjunctiva and lacrimal gland, at much higher levels than those measured for PPARα and PPARβ/δ. Dry eye rats and diabetic rats both showed decreased tear secretion, shortened BUT, and increased corneal staining. Significant changes in gene expression were observed compared with the control group. In the lacrimal glands of dry eye rats and diabetic rats, expression of PPARγ decreased (P<0.05), expression of Sirt1 also decreased (P<0.01), whereas expression of TNF-α, IL-1β, IL-6, MyD88, and TGF-β increased (P<0.05). Among PPARs, PPARγ might play a dominant role in the regulation of metabolic- and inflammatory-signaling pathways on the ocular surfaces and in lacrimal glands. Down-regulation of PPARγ is highly relevant to lacrimal gland dysfunction under desiccating-stress and diabetic conditions. PPARγ, thus, is a potential therapeutic target in the treatment of environment- or diabetes-induced dry eye diseases.

Resistance of the murine cornea to bacterial colonization during experimental dry eye

The healthy cornea is remarkably resistant to infection, quickly clearing deliberately inoculated bacteria such as Pseudomonas aeruginosa and Staphylococcus aureus. Contrasting with the adjacent conjunctiva and other body surfaces, it also lacks a resident viable bacterial microbiome. Corneal resistance to microbes depends on intrinsic defenses involving tear fluid and the corneal epithelium. Dry eye, an ocular surface disease associated with discomfort and inflammation, can alter tear fluid composition and volume, and impact epithelial integrity. We previously showed that experimentally-induced dry eye (EDE) in mice does not increase corneal susceptibility to P. aeruginosa infection. Here, we explored if EDE alters corneal resistance to bacterial colonization. EDE was established in mice using scopolamine injections and dehumidified air-flow, and verified by phenol-red thread testing after 5 and 10 days. As expected, EDE corneas showed increased fluorescein staining versus controls consistent with compromised epithelial barrier function. Confocal imaging using mT/mG knock-in mice with red-fluorescent membranes revealed no other obvious morphological differences between EDE corneas and controls for epithelium, stroma, and endothelium. EDE corneas were imaged ex vivo and compared to controls after alkyne-functionalized D-alanine labeling of metabolically-active colonizing bacteria, or by FISH using a universal 16S rRNA gene probe. Both methods revealed very few viable bacteria on EDE corneas after 5 or 10 days (median of 0, upper quartile of ≤ 1 bacteria per field of view for each group [9–12 eyes per group]) similar to control corneas. Furthermore, there was no obvious difference in abundance of conjunctival bacteria, which included previously reported filamentous forms. Thus, despite reduced tear flow and apparent compromise to corneal barrier function (fluorescein staining), EDE murine corneas continue to resist bacterial colonization and maintain the absence of a resident viable bacterial microbiome.

Ophthalmic examination, biometry, and histologic findings in captive inland bearded dragons (Pogona vitticeps).

To report ophthalmic examination, biometry, phenol red thread test (PRTT), intraocular pressure (IOP), and histologic findings from a private collection of inland bearded dragons (Pogona vitticeps). Fourteen inland bearded dragons. Complete ophthalmic examinations were performed on all animals, including slit-lamp biomicroscopy, indirect ophthalmoscopy, fluorescein stain, phenol red thread test, and rebound tonometry. B-mode ultrasonography was used to measure anterior chamber depth, axial lens thickness, vitreal chamber depth, and axial globe length. Horizontal corneal diameter was estimated using ImageJ software. Histologic assessment was obtained for one of the bearded dragons that died following the study period. The median PRTT value was 7.27mm/15seconds. Mean IOP was 6.29±1.60mmHg and 2.14±1.37mmHg using the dog and undefined calibration settings, respectively. Median axial globe length was 11.75mm. Mean anterior chamber depth and mean lens thickness were 2.06±0.35mm and 3.38±0.45mm, respectively. Median vitreal chamber depth was 6.79mm. Mean horizontal corneal diameter was 5.138±0.346mm. Two distinct ocular phenotypes were observed, with two of the bearded dragons having corneal globosa, deep anterior chambers, and tufts of iridal vessels and fibrillar material extending into the anterior chamber. The ultrasound biometry, PRTT, and rebound tonometry results may serve as a guideline for ophthalmic parameters in healthy bearded dragons. Examination and testing of greater numbers of animals are necessary to establish true reference ranges and determine if the observed ocular phenotypes represent normal variants or pathologic changes.

Effect of Intramuscular Medetomidine Administration on Tear Flow in Rats.

Medetomidine has been reported to decrease tear flow significantly in dogs, cats, and pigs when used as a sedative or analgesic; however, there are no such reports when it comes to rats. The present study aimed to investigate the effect of medetomidine on tear flow in rats. Medetomidine in doses of 50, 100, or 200 µg/kg or a physiological saline solution as the control, were administered intramuscularly to male Slc:Wistar/ST rats. After the administration of medetomidine, tear flow in both eyes was measured using a phenol red thread tear test. The area under the curve (AUC) of phenol red thread test values from baseline to 8 h was calculated. Data were plotted against the dose of medetomidine and simple linear regression analysis was performed. The effect of the drug on phenol red thread test values was considered dose-related when linear analysis yielded a significant relationship. In all medetomidine-treated groups, tear flow decreased significantly in both eyes after administration, while no significant changes were observed in either eye in the control group. The AUC values from baseline to 8 h after administration in groups treated with 100 and 200 µg/kg of medetomidine were significantly lower in both the left and right eyes compared to the control group. The linear regression of the AUC values was significant for both eyes. Our results indicated that the intramuscular administration of medetomidine in rats decreased tear flow significantly in a dose-dependent manner.

Dry Eye Disease Practice in Ghana: Diagnostic Perspectives, Treatment Modalities, and Challenges

There is a dearth of studies investigating the challenges encountered in dry eye practice. Profiling these barriers is crucial to improving dry eye diagnosis and patient care. This study aimed to examine the diagnostic and treatment perspectives, and challenges in dry eye practice in Ghana. An anonymous paper-based or web survey regarding dry eye practice pattern, practice challenges, and access to diagnostic tools was distributed to 280 potential participants. One hundred thirteen respondents completed the survey. Case history (92.5%), fluorescein tear breakup time (87.5%), and corneal fluorescein staining (72.5%) were the topmost procedures used for dry eye diagnosis. A preserved lubricant drop was the most commonly prescribed treatment of mild, moderate, and severe dry eye at the rates of 77.0, 83.2, and 77.0%, respectively. A few respondents prescribed cyclosporine (2.7%) or punctal plugs (5.3%) across all disease severities, and none used scleral lens, autologous serum tears, or thermal pulsation. Graduate professional training influenced the practice pattern of 82.3% of respondents, whereas continuing professional education influenced less than 1%. Approximately 70.1 and 92.8% of optometrists considered referring dry eye in children and cases that are unresponsive to treatment, respectively. Eighty-eight percent of practitioners indicated they experience a challenge in dry eye practice, with limited access to diagnostic tools (77.9%) and limited availability of effective dry eye medication on the Ghanaian market (50.4%) being the most frequent challenges. More than 85% of respondents had access to a fluorescein dye or slit-lamp biomicroscope; however, none had access to a phenol red thread, lissamine green dye, osmolarity technology, or meibography device. Practitioners' limited access to diagnostic tools/techniques and the limited effective dry eye treatments are major challenges encountered in dry eye practice in Ghana. Addressing these will improve dry eye practice and treatment outcomes in the country.

High-fat diet induces dry eye-like ocular surface damages in murine

PurposeA high-fat diet leads to dysfunction in multiple systems of the body. Herein we investigate the effects of a high-fat diet on the ocular surface using a murine model. MethodsFour-week-old male C57BL/6 mice were fed with a standard-fat diet (10 kcal% fat, SFD) or a high-fat diet (60 kcal% fat, HFD) for 1 or 3 months. Phenol red thread test was used to detect tear production, oregon green dextran (OGD) staining was performed to assess corneal epithelial permeability, and PAS staining was conducted to ascertain the presence of conjunctival goblet cells. Squamous metaplasia in the ocular surface and corneal epithelial barrier function were detected by immunofluorescent staining, zymography and Western blot analysis. Oxidative stress related protein expression was evaluated by immunostaining and Western blot analysis. Corneal and conjunctival cell apoptosis was determined by TUNEL assay and caspase-3 expression. ResultsA HFD induced obvious ocular surface damages, including decreased tear production, notable OGD staining and distinct goblet cell loss. It also resulted in corneal epithelial barrier dysfunction and significant squamous metaplasia of the corneal and conjunctival epithelia. The HFD also upregulated key factors that regulate oxidative stress in the ocular surface, and upregulated cell apoptosis in ocular surface epithelial cells. ConclusionsA HFD induces dry eye-like ocular surface damages in mice via the activation of oxidative stress and an induction of apoptosis in the cells of the ocular surface.

Normative ocular data for juvenile and adult Japanese quail (Coturnix japonica).

To obtain normative ocular data for Japanese quail as they mature from juveniles to adults. Twenty-six captive Japanese quail comprising thirteen males and thirteen females, free of ocular disease, were included in the study. Ophthalmic reference values were measured in both eyes at 1 and 5months of age. A complete ophthalmic examination was performed, including neuro-ophthalmic reflexes, slit lamp biomicroscopy, phenol red thread test (PRTT), rebound tonometry, fluorescein staining, horizontal corneal diameter measurement, indirect ophthalmoscopy, and ocular ultrasound biometry. Ultrasound biomicroscopy measurements of axial globe length, lens thickness, vitreal chamber length, and pecten length were recorded. The depth of the anterior chamber was calculated by subtracting the lens thickness and vitreous length from the axial globe length. Measures of association and descriptive statistics were analyzed using STATA-14 and STATA-15. Juvenile and adult females were heavier than age-matched males. Weight, intraocular pressure, horizontal corneal diameter, axial globe length, and lens thickness measurements increased with age. No statistically significant differences were found in the remainder of measurements among individuals in different sex or age-groups. This work provides reference values and clinical findings that can be used in future research on quail and ocular disease.

Treating Uncomfortable Contact Lens Wear With Orthokeratology.

Many contact lens (CL) users permanently discontinue wear because of ocular dryness and discomfort. This study aimed to determine whether refitting symptomatic soft CL wearers in to orthokeratology could improve ocular symptoms and signs. This was a prospective, 3-month, open-label study of symptomatic (Contact Lens Dry Eye Questionnaire [CLDEQ-8] ≥12) soft CL wearers who were between the ages of 18 and 45 years. All subjects were refit into orthokeratology CLs (Emerald, Euclid Systems). The following tests were completed: CL history, Standardized Patient Evaluation of Eye Dryness (SPEED) questionnaire, CLDEQ-8, CLDEQ-4, logarithm of the minimum angle of resolution visual acuity, pupil size, refractive error, slit-lamp biomicroscopy, noninvasive tear break-up time, tear meniscus height, phenol red thread, conjunctival staining, corneal aesthesiometry, and corneal topography. Twenty-nine of 40 qualifying subjects (age=24.43±4.62 years) completed the study. No significant differences were detected between completed and noncomplete subjects. Completed subjects had significantly better CLDEQ-8, CLDEQ-4, and SPEED scores at 3 months compared with baseline. Completed subjects had significantly better conjunctival staining scores and flatter keratometry values at 1 month compared with baseline. Although not all symptomatic soft CL wearers were able to be refit into orthokeratology, subjects who were wearing orthokeratology at 3 months had a significant and clinically meaningful improvement in ocular symptoms. Additional work is needed to determine the mechanism leading to improved comfort because few clinical signs were changed after switching to orthokeratology.

Associations between the menstrual cycle, lifestyle factors and clinical assessment of the ocular surface: a prospective observational study

BackgroundLittle is known about the ocular surface changes over the menstrual cycle in young women and the interactions with lifestyle factors. Therefore, the purpose of this study was to explore the associations between modifiable lifestyle factors and menstrual cycle phases on the ocular signs and symptoms of dry eye in young healthy women.MethodsThis was a prospective 1-month observational study. Thirty young healthy women with regular, 24 to 32-day menstrual cycles were recruited. Participants attended three visits at day 7, 14, and 21 (± 1) of their menstrual cycle. At baseline, general health questionnaire was conducted. At each visit, symptomology was quantified using Ocular Surface Disease Index (OSDI) and overall ocular comfort (OOC, visual analogue scale). Ocular signs were assessed using Efron scales, tear break-up time (TBUT) and phenol red thread (PRT). Pearson’s correlation was used to determine associations between variables at each visit.ResultsA total of 26 participants (mean age = 22.3 ± 3.7 years) with an average menstrual cycle of 28.3 ± 1.3 days completed the 3 visits. The interaction between signs/symptoms and lifestyle factors changed over the cycle. At the follicular phase (day 7), lifestyle factors such diet and levels of stress were correlated with PRT and OSDI, (r = − 0.4, p = 0.022; r = 0.4, p = 0.045 respectively). At the ovulation phase (day 14), the general health score was correlated with OOC scores (r = 0.4, p = 0.047). At day 14, exercise frequency correlated with PRT (r = − 0.4, p = 0.028) and caffeine intake was positively correlate with both; TBUT (r = 0.5, p = 0.020) and PRT (r = 0.5, p = 0.014). At the luteal phase (day 21), we found no correlations between lifestyle factors and dry eye signs or symptoms.ConclusionsThe associations between lifestyle factors and objective and subjective ocular surface assessment appeared to be more pronounced during the ovulation phase of the menstrual cycle compared to the follicular and luteal phases. Misalignment of these factors with the ocular health during the luteal phase could be attributed to central sensitization and changes in levels of luteinising hormone. Natural hormonal changes during menstrual cycle should be considered for diagnosis and treatment of dry eye in young healthy women.

Contact lens and eye glass wearers with and witouth ocular symptoms: differences in corneal sensitivity, blinking, tearing and corneal surface temperature

AbstractPurposeTo analyze corneal sensitivity, blink frequency (BF), tearing rate (TR), TBUT, and corneal surface temperature (CST) in young contact lens (CLs) and eye glass (EGs) wearers with and without ocular discomfort symptoms.MethodsEGs (n = 18) and CLs (n = 23) young subjects (18–40 years old, both sexes) participated voluntarily. CLs were classified as asymptomatic (A) or symptomatic (S) depending on their OSDI score (&lt; 13 or ≥ 13, respectively). Corneal sensitivity to mechanical and chemical air puffs (3s duration, applied with a gas esthesiometer) and cold (4°C) saline drops was explored. Sensations evoked by each stimulus was scored with 0 to 10 VAS. BR (1 min at rest or during a task), TR (mm of wet phenol red threads, 15 s), TBUT (s), and CST (IR video thermography) were also measured.ResultsVAS values of irritation sensation evoked by mechanical and chemical stimulation (p &lt; 0.05) were higher in CLs than in EGs while VAS values of cold sensation evoked by saline drops were similar in both groups. Although CST and TR were similar in EGs and CLs, TBUT was significantly shorter (p &lt; 0.001) and BR was higher in CLs both at rest (p &lt; 0.001) and during a visual task (p &lt; 0.01). Although VAS values scored to corneal mechanical, chemical and cold stimulation were lower in CL‐S than in CL‐A, no differences were found in BR at rest or during the task, TR, TBUT and CST. Corneal sensitivity and CST were also similar in EG‐A and EG‐S, although TR (p &lt; 0.05) and BF at rest (p &lt; 0.05), but not during the task, were higher in EG‐S.ConclusionsResults show a reduced corneal sensitivity in symptomatic CL wearers, which suggests that corneal sensory nerve activity must be altered in a different degree in asymptomatic and symptomatic individuals, thus leading to changes in tearing and blinking regulation.Support: AEI‐ERDF SAF‐2017‐83674‐C2‐1‐R and 2‐R

Ophthalmic findings in cinereous vultures (Aegypius monachus).

The aim of the present study was to provide ophthalmic reference values under normal physiological conditions for Aegypius monachus (cinereous vulture). Thirty-two eyes of sixteen adult captive cinereous vultures were used for this study. Tear tests and tonometry in conscious and anesthetized states, neuro-ophthalmic tests, measurement of corneal diameter, slit-lamp biomicroscopy, ophthalmoscopy, and funduscopy were performed. Schirmer tear test (STT) value was 11.4±2.6 and 11.5±2.8mm/min in the right (OD) and left eye (OS), respectively. Phenol red thread test (PRT) values were 22.3±2.1mm/15s OD and 22.8±3.0mm/15s OS. The results showed a strong correlation between STT and PRT in both eyes. Intraocular pressure (IOP) values were 32.8±6.9mmHg OD and 31.9±7.1mmHg OS with TonoVet and 20.7±4.5mmHg OD and 19.5±4.1mmHg OS with Tono-Pen. There were significant differences in IOPs between rebound and applanation tonometry in both OD and OS. Tear production and IOP values showed significant reductions with general anesthesia in both tear tests and both tonometry (P<.001). Horizontal corneal diameter (mm) was 15.56±0.96 OD and 15.56±0.96 OS. Vertical diameter (mm) was 14.13±0.96 OD and 14.06±1.06 OS. The horizontal diameter was significantly longer than vertical diameter (P<.001). Ocular morphologic information and normal reference range values for various ophthalmic measurements were obtained in clinically healthy cinereous vultures, which can facilitate accurate diagnosis and better management of ophthalmic diseases in cinereous vultures.

Prior inhibition of AKT phosphorylation by BX795 can define a safer strategy to prevent herpes simplex virus-1 infection of the eye

PurposeTo evaluate the prophylactic antiviral efficacy, corneal tolerance and toxicity of topically dosed BX795, a non-nucleoside small-molecule inhibitor of herpes simplex virus type-1 (HSV-1). MethodsProphylactic treatment with BX795 was performed both in-vitro on human corneal epithelial cells and in-vivo on mice prior to HSV-1 challenge. Viral burden was evaluated using a standard plaque assay. In a separate experiment, mice were treated topically 3-times daily for 4-weeks with BX795 to evaluate corneal tolerance and toxicity. Phenol-red thread measurements, fluorescein staining and optical coherence tomography (OCT) were used to evaluate tear production, dryness and corneal structural changes. Corneal sensitivity and intraocular pressure were measured using esthesiometery and tonometery respectively. ResultsBoth in-vitro and in-vivo results showed a robust suppression of HSV-1 infection when treated prophylactically with BX795. The fluorescein stain and phenol-red results for the BX795-treated eyes did not show signs of corneal surface dryness when compared to trifluridine (TFT), an FDA-approved topical antiviral. The OCT measurements showed no signs of structural changes to the cornea suggesting that BX795 treatment was well tolerated without any apparent signs of toxicity or inflammation. The corneal sensitivity of BX795-treated eyes was not significantly different from TFT-treated eyes. No significant increase in the intraocular pressure of BX795-treated mice was observed. ConclusionsProphylactic treatment with BX795 protects corneal cells from HSV-1 infection. The antiviral is well-tolerated on murine corneas without any detectable toxicity.

Graft Versus Host Disease-Associated Dry Eye: Role of Ocular Surface Mucins and the Effect of Rebamipide, a Mucin Secretagogue

The present study was designed to investigate the role of ocular surface glycocalyx and mucins in graft versus host disease (GVHD)-associated dry eye. The ameliorative effect of topical rebamipide, a mucin secretagogue, on GVHD-associated dry eye was also tested. A mouse model of allogeneic transplantation was used to induce ocular GVHD with C57BL/6 as donors and B6D2F1 as recipient mice. Phenol red thread method and fluorescein staining was used to quantify tear secretion and corneal keratopathy. At 8 weeks after the allogeneic transplantation, corneas were harvested to perform glycocalyx staining and confocal microscopy. Goblet cell staining was performed using periodic acid Schiff's staining. Corneal and tear film levels of Mucin 1, 4, 16, 19, and 5AC were quantified using ELISA and real-time PCR. Rebamipide was applied topically twice daily to mice eyes. Allogeneic transplantation resulted in ocular GVHD-associated dry eye characterized by a significant decrease in tear film volume and the onset of corneal keratopathy. Ocular GVHD caused a significant decrease in the area and thickness of corneal glycocalyx. A significant decrease in the goblet cells was also noted. A significant decrease in mucin 4 and 5AC levels was also observed. Topical treatment with rebamipide partially attenuated ocular GVHD-mediated decrease in tear film volume and significantly reduced the severity of corneal keratopathy. Ocular GVHD has detrimental impact on ocular surface glycocalyx and mucins. Rebamipide, a mucin secretagogue, partially prevents ocular GVHD-associated decrease in tear film and reduces the severity of corneal keratopathy.

Ocular findings and selected ophthalmic diagnostic tests in a group of young commercially available Guinea and Skinny pigs (Cavia porcellus).

The purpose of this study is to evaluate a group of young commercially available Skinny pigs, to gain information regarding ocular findings in this breed of guinea pig. Comparisons of ocular findings are to be made between Skinny pigs and haired guinea pigs. Ten haired guinea pigs and ten Skinny pigs were examined. A complete ophthalmic examination including Schirmer tear test-II (STT-II), phenol red thread test (PRTT), rebound tonometry with TonoVet PLUS, Fluorescein and Rose Bengal stain was performed. Microbiology swabs for aerobic bacterial growth were collected from conjunctiva of both eyes prior to the ophthalmic examination. The ophthalmic examination revealed seven abnormal ocular findings: trichiasis, mucopurulent discharge, hyperemia/chemosis of the conjunctiva, corneal fibrosis, corneal vascularization, and foreign body on the cornea or conjunctiva. Skinny pigs had a significantly higher amount of mucopurulent discharge (P=.0133) and a significantly higher STT-II (P<.001) than haired guinea pigs. Although not significant, trichiasis, keratitis with corneal vascularization, and foreign body presence were more common in Skinny pigs. Significantly more Skinny pigs had Pasteurellaceae isolated from their conjunctiva than haired guinea pigs (P=.0112). Antimicrobial susceptibility for the five Pasteurellaceae organisms isolated revealed susceptibility toward oxytetracycline, tobramycin, ciprofloxacin, and ofloxacin, whereas resistance was found toward erythromycin, trimethoprim-sulfamethoxazole, and moxifloxacin. Young Skinny pigs have a higher risk of Pasteurellaceae-associated conjunctivitis. Oxytetracycline, tobramycin, ciprofloxacin, and ofloxacin were identified as topical antibiotics that may be useful for Pasteurellaceae-associated conjunctivitis in Skinny pigs.

Assessment of Ocular Tear Film Stability in Subjects with High Total Cholesterol Levels

AbstractBackground: High cholesterol levels are known to cause multiple complications and the correlations between dry eye disease and high cholesterol levels can be used as an indicator of the need for urgent treatment to prevent severe ocular complications.Aim of Study: This study aimed to assess ocular tear film stability in subjects with high total cholesterol levels by using various dry eye diagnostic tests.Subjects and Methods: Twenty male subjects aged 19-43 years (32.5±7.3 years) with a high total cholesterol level (6.2±0.7mmol/L) and an age-matched control group of twenty male subjects (19-40 years; 31.1±4.6 years) with normal total cholesterol levels (3.9±0.6mmol/L) participated in the study. All subjects completed the ocular surface disease index assessment first, followed by the non-invasive tear break-up time (NITBUT) test. After 10 minutes, the tear meniscus time (TMH) test was performed followed by phenol red thread (PRT) and tear ferning (TF) tests, with a 10-minute gap between the tests.Results: The mean scores (p<0.05) in the NITBUT and TMH tests indicated a dry eye condition in the study group [7.5 (3.3) s and 0.15 (0.12) mm, respectively] and a normal eye condition in the control group [15.3 (4.1) s and 0.27 (0.06) mm, respectively]. The average score for the TF grade (p<0.05) showed eye dryness [2.2 (1.8)] in the study group and a normal eye condition in the control group [0.5 (1.5)]. The cholesterol level showed a medium correlation with age (r=0.473; p=0.035), a strong negative correlation with the PRT score (r=-0.524; p=0.018), and a strong correlation with the TF grade (r=0.530; p=0.016).Conclusion: The total cholesterol level significantly influences ocular tear film stability. Both tear quantity and quality decreased in subjects with high total cholesterol levels, which led to meibomian gland dysfunction and disturbances in lipid production and blood and oxygen supply to eye tissues, thereby causing dry eye symptoms.