Effects of combined intense pulsed light and cyclosporine 0.05% eyedrops in ocular surface matrix metalloproteinase-9 levels in patients with moderate-to-severe MGD.

To investigate the changes in meibomian gland dysfunction (MGD) and tear matrix metalloproteinase-9 (MMP-9) levels in patients with moderate-to-severe MGD after combined treatment with intense pulsed light (IPL) therapy and cyclosporine 0.05%. Thirty-six patients concurrently treated with IPL and cyclosporine 0.05% ophthalmic drops were retrospectively enrolled. Tear break up time (TBUT), corneal and conjunctival staining scores, Schirmer test, and ocular surface disease index (OSDI) questionnaire responses were recorded. Meibum quality, consistency, and eyelid margin telangiectasia were evaluated. MMP-9 levels were examined by the positivity and signal intensity of red lines (scored 0-4). IPL was performed four times with a vascular filter at 2-week intervals, followed by a 1-month follow-up after treatment cessation. Immediately after each IPL treatment, gentle meibomian gland expression was performed in both the upper and lower eyelids using meibomian gland expressor forceps. TBUT (1.88 ± 1.02 s to 3.12 ± 1.08 s, p < 0.001), corneal and conjunctival staining (6.19 ± 2.11 to 3.12 ± 1.89, p < 0.001), Oxford staining grade (2.66 ± 0.89 to 1.35 ± 0.76, p < 0.001), and OSDI (52.97 ± 21.86 to 36.36 ± 22.45, p < 0.001) scores significantly improved after the combined treatment. Meibum quality, consistency and lid margin telangiectasia showed significant post-treatment improvement in both the upper and lower eyelids. MMP-9 positivity showed a significant decrease (97-69%, p = 0.026) with a reduction in signal intensity (2.72 ± 0.87 to 2.09 ± 0.95, p = 0.011). The combination of IPL therapy and 0.05% cyclosporine eye drops effectively treats moderate-to-severe MGD by reducing symptoms and signs of MGD and by decreasing ocular surface MMP-9-associated inflammation.

Blue Light Induces Impaired Autophagy through Nucleotide-Binding Oligomerization Domain 2 Activation on the Mouse Ocular Surface.

In this study, we investigated the effects of blue light exposure on nucleotide-binding oligomerization domain 2 (NOD2) expression on the mouse ocular surface and evaluated the role of NOD2 activation in light-induced cell death. Mice were divided into wild-type (WT), NOD2-knock out (KO), WT + blue light (WT + BL), and NOD2-KO + blue light (NOD2-KO + BL) groups, and the mice in the WT+BL and NOD2-KO + BL groups were exposed to blue light for 10 days. After 10 days of blue light exposure, increased reactive oxygen species and malondialdehyde were observed in the WT + BL and NOD2-KO + BL groups, and the WT + BL group showed a higher expression of NOD2 and autophagy related 16 like 1. Although both WT+BL and NOD2-KO + BL groups showed an increase in the expression of light chain 3-II, NOD2-KO + BL mice had a significantly lower p62 expression than WT + BL mice. In addition, NOD2-KO+BL mice had significantly lower corneal epithelial damage and apoptosis than WT + BL mice. In conclusion, blue light exposure can induce impaired autophagy by activation of NOD2 on the ocular surface. In addition, the reactive oxygen species (ROS)-NOD2-autophagy related 16 like 1 (ATG16L) signaling pathway may be involved in the blue-light-induced autophagy responses, resulting in corneal epithelial apoptosis.

Repurposing blue laser autofluorescence to measure ocular sun exposure.

IMPORTANCE: Excessive ocular sun exposure is linked to various eye pathologies. Conjunctival ultraviolet autofluorescence (CUVAF) is a method of detecting sun-related conjunctival damage; however, the custom-built camera system required is not readily available. BACKGROUND: We investigated whether blue laser autofluorescence (BAF) on a commonly used confocal scanning laser ophthalmoscope (cSLO) can be utilized to measure CUVAF area. DESIGN: Cross-sectional evaluation of a diagnostic technology at a medical research institute. PARTICIPANTS: Sixty-four participants recruited from three on-going observational eye studies in Western Australia. METHODS: All participants had four images, two of each eye, captured using the CUVAF camera and BAF on the same day. Participants with pterygium or poor quality images were excluded from the analysis. Two graders measured CUVAF area in each image twice. CUVAF area measured by BAF was then compared to measurements determined with the conventional camera system. MAIN OUTCOME MEASURES: CUVAF area. RESULTS: After exclusions, 50 participants' images were analysed. Intra- and inter-observer repeatability were similar between the two systems. When comparing CUVAF area measured by BAF to the camera measurement, grader 1 had a mean difference of +1.00 mm2 , with 95% limits of agreement -5.75 to 7.77 mm2 . Grader 2 had a mean difference of +0.21mm2 , with 95% limits of agreement -7.22 to 7.64 mm2 . CONCLUSIONS AND RELEVANCE: BAF on a commercially available cSLO is a valid method for measuring CUVAF area. This finding provides broader opportunity for identifying, monitoring and educating patients with sun-exposure-related ocular conditions and for researching the ocular impacts of sun exposure.

EFFECT OF SUN EXPOSURE DURATION ON CYCLOOXYGENASE-2 EXPRESSION IN THE CONJUNCTIVA.

Pterygium is a multifactorial proliferative pathologic change of bulbar conjunctiva. The purpose of this study was to determine the effect of the duration of exposure to solar radiation (expressed in years) on the incidence of positive cyclooxygenase-2 (COX-2) finding in conjunctival tissue in two groups of patients. Group 1 consisted of 68 patients with primary pterygium having undergone conjunctival autograft transplantation. Group 2 consisted of 43 patients with morphologically unchanged conjunctivae that were harvested during cataract surgery. All 111 specimens were submitted to immunohistochemical staining for monoclonal COX-2 antibody (1:100; M361701 MO A-HU, Dako, Santa Clara, California, USA). The immunostaining intensity in the surface epithelium was scored using the following grading system: 0 no immunostaining; + weak immunostaining (few cells being positive focally or scattered); ++ medium immunostaining; and +++ strong immunostaining (diffuse staining throughout the tissue). The analysis of COX-2 activity yielded 29 (42.6%) positive findings in group 1 and 27 (62.8%) positive findings in group 2. Group 2 consisted of statistically significantly older individuals with a history of considerably longer sun exposure. Statistical analysis proved the duration of exposure to solar radiation to be the most important factor in positive COX-2 findings.

Effects of Riboflavin and Ultraviolet Illumination on the Biomechanical Properties of Conjunctiva.

PURPOSE: Our experiment evaluated the biomechanical effects of riboflavin and ultraviolet A illumination, in terms of covalent bonding, permeability, and indentation rupture force, on excised cattle conjunctiva. MATERIALS AND METHODS: Cattle conjunctiva was extracted and divided into the treatment group, which was soaked in riboflavin, followed by ultraviolet light illumination, and the control group. Samples were subsequently analysed on a Fourier transform infrared spectrum test to identify the presence of amide bonds, a permeability test to assess the diffusion of methylene blue across conjunctiva, and an indentation rupture force test. RESULTS: The Fourier transform infrared spectrum test showed a significantly increased amide I band after treatment (p = 0.043), as well as in amide II, amide A, and amide B bands. The permeability test showed a reduced permeability to methylene blue after treatment (n = 25) compared to the control (n = 24; p = 0.03). The indentation rupture test showed a higher maximal rupture force in the treated samples (n = 10; p = 0.07). CONCLUSIONS: The study suggested that riboflavin and ultraviolet A illumination (commercially available as collagen crosslinking) strengthened cattle conjunctiva by increasing its amount of covalent bonds, reducing its permeability, and possibly improving its resistance to rupture. This is the first study in the collagen crosslinking literature on the biomechanical properties of conjunctival tissue.

Seasonal Effect on Ocular Sun Exposure and Conjunctival UV Autofluorescence.

PURPOSE: To evaluate feasibility and repeatability of measures for ocular sun exposure and conjunctival ultraviolet autofluorescence (UVAF), and to test for relationships between the outcomes. METHODS: Fifty volunteers were seen for two visits 14 ± 2 days apart. Ocular sun exposure was estimated over a 2-week time period using questionnaires that quantified time outdoors and ocular protection habits. Conjunctival UVAF was imaged using a Nikon D7000 camera system equipped with appropriate flash and filter system; image analysis was done using ImageJ software. Repeatability estimates were made using Bland-Altman plots with mean differences and 95% limits of agreement calculated. Non-normally distributed data was transformed by either log10 or square root methods. Linear regression was conducted to evaluate relationships between measures. RESULTS: Mean (±SD) values for ocular sun exposure and conjunctival UVAF were 8.86 (±11.97) hours and 9.15 (±9.47) mm, respectively. Repeatability was found to be acceptable for both ocular sun exposure and conjunctival UVAF. Univariate linear regression showed outdoor occupation to be a predictor of higher ocular sun exposure; outdoor occupation and winter season of collection both predicted higher total UVAF. Furthermore, increased portion of day spent outdoors while working was associated with increased total conjunctival UVAF. CONCLUSIONS: We demonstrate feasibility and repeatability of estimating ocular sun exposure using a previously unreported method and for conjunctival UVAF in a group of subjects residing in Ohio. Seasonal temperature variation may have influenced time outdoors and ultimately calculation of ocular sun exposure. As winter season of collection and outdoor occupation both predicted higher total UVAF, our data suggests that ocular sun exposure is associated with conjunctival UVAF and, possibly, that UVAF remains for at least several months after sun exposure.

Inflammation and keratoconus.

Keratoconus (KC) has been traditionally classified as a noninflammatory disease. Barring loss of function, the other classic signs of inflammation (heat, redness, swelling, pain) are not usually obvious or even apparent in KC. This clinical perspective examines the evidence and implications of numerous inflammatory processes that have been recognized in the tears of KC patients as well as some inflammation relevant differences found in the KC cornea. The roles of inflammation in corneal trauma attributed to eye rubbing and/or contact lens wear are examined as is the significance of atopy, allergic disease, dry eye disease, degradative enzyme activity, wound healing, reduced anti-inflammatory capacity, and ultraviolet irradiation. It is possible that any comorbidity that is inflammatory in nature may add synergistically to other forms of KC-related inflammation and exacerbate its pathogenetic processes. For example, some features of inflammation in ocular rosacea and associated corneal thinning and distortion could have some possible relevance to KC. An analogy is drawn with osteoarthritis, which also involves significant inflammatory processes but, like KC, does not meet all the classic criteria for an inflammatory disease. Classifying KC as quasi-inflammatory (inflammatory-related) rather than a noninflammatory disease appears to be more appropriate and may help focus attention on the possibility of developing effective anti-inflammatory therapies for its management.

Pterygium and conjunctival ultraviolet autofluorescence in young Australian adults: the Raine study.

BACKGROUND: Sun exposure is associated with several ophthalmic diseases, including pterygium which may develop in adolescence. This study reports the prevalence of pterygium and its associations in a large cohort of young Australian adults. Conjunctival ultraviolet autofluorescence, a biomarker of ocular sun exposure, has recently been characterized in some Australian populations. DESIGN: Cross-sectional population-based study. PARTICIPANTS: One thousand three hundred forty-four subjects aged 18-22 years in the Western Australian Pregnancy Cohort (Raine) Study. METHODS: Standardized colour and ultraviolet autofluorescence photographs of the nasal and temporal conjunctiva were taken, and assessed for presence of pterygium and area of autofluorescence. Sun exposure and protective factors were assessed by structured questionnaire. MAIN OUTCOME MEASURES: Area of conjunctival ultraviolet autofluorescence in square millimetre (mm(2)) and presence of pterygium. RESULTS: Median total conjunctival autofluorescence was 44.2 mm(2) (interquartile range 20.2-69.8 mm(2)). Median conjunctival autofluorescence was higher in nasal than in temporal quadrants (23.8 mm(2) vs. 18.9 mm(2), P < 0.001), but did not differ according to age or gender. Higher body mass index was associated with lower levels of autofluorescence. Total autofluorescence increased with increasing time spent outdoors. Prevalence of pterygium was 1.2% (95% confidence interval 0.6-1.8%), and was associated with male gender (odds ratio 6.71, P = 0.012). Participants with pterygium had significantly more conjunctival autofluorescence than those without (median 73.4 mm(2) vs. 44.0 mm(2), P = 0.001). CONCLUSIONS: Conjunctival ultraviolet autofluorescence is associated with increased time spent outdoors, and increased prevalence of pterygium. The association of this biomarker with other ophthalmohelioses, including cataract, ocular surface squamous neoplasia and eyelid malignancy, has yet to be determined.

Changes in the eyelids and conjunctiva caused by ultraviolet radiation.

The aim of this study was to show the frequency, sex and age distribution of eyelids skin tumor changes and degen erative changes of the conjunctiva for the period of three years (2011-2013) at the Department of Ophthalmology in Split. We analyzed the eyelids skin lesions in biopsy material at the Department of Pathology and the same were compared with the profession of the patients. In this period there were found 131 tumor changes of the eyelids. The most common tumor was the basal cell carcinoma (118) with the higher frequency in women. There were 10 squamous cell carcinomas with the equal representation among sexes and three melanomas. There were 79 female and 52 male patients. There were 299 pterygiums operated with the higher frequency in women (68.2%). Exposure to UV radiation, particulary UVB radiatiori is the most common causative factor for genetic abnormalities in cells and provoked factor in oncogenesis of skin tumors. In our research we found a correlation between changes in the eyelids and conjunctiva caused by UV radiation with the professional interest of the respondents. Due to high incidence of eyelids skin tumor changes in the population professionally exposed to UV radiation, medical professionals should be aware of the importance of the public education on the etiology of these tumors and the importance of the UVprotection.

[Morphologically reasonable application of 1.44 microm Nd:YAG laser in ocular surgery for distant hemostasis in conjunctival and episcleral vessels].

The article discusses morphological changes in bulbar conjunctiva and episclera after experimental exposure to Nd:YAG laser radiation at 1.44 pm in comparison to the effect of diathermal coagulator Mira TR4000. The results proved the use of 1.44 microm Nd:YAG laser in ocular surgery for distant hemostasis morphologically reasonable. Non-contact and directional laser treatment is more delicate as it produces smaller irradiated area. The depth of penetration and tissue heating is very limited. Neither excessive reparation, nor scarring is found in the exposed area. On the contrary, diathermy is a contact procedure associated with irregular distribution of heat, which causes large tissue burns and necrosis with subsequent adherent scar formation.

Blue light induced ferroptosis via STAT3/GPX4/SLC7A11/FTH1 in conjunctiva epithelium in vivo and in vitro.

The prevalence of Light-emitting diodes (LEDs) has exposed us to an excessive amount of blue light (BL) which causes various ophthalmic diseases. Previous studies have shown that conjunctiva is vulnerable to BL. In this study, we aimed to investigate the underlying mechanism of BL-induced injury in conjunctiva. We placed C57BL/6 mice and human conjunctival epithelial cell lines (HCECs) under BL (440 nm ± 15 nm, 0.2 mW/cm2) to establish a BL injury model in vivo and in vitro. Immunohistochemistry and MDA assay were used to identify lipid peroxidation (LPO) in vivo. HE staining was applied to detect morphological damage of conjunctival epithelium. DCFH-DA, C11-BODIPY 581/591, Calcein-AM, and FeRhoNox™-1 probes were performed to identify ferroptosis levels in vitro. Real-time qPCR and Western blotting techniques were employed to uncover signaling pathways of blue light-induced ferroptosis. Our findings demonstrated that BL affected tear film instability and induced conjunctival epithelium injury in vivo. Ferrostatin-1 significantly alleviated blue light-induced ferroptosis in vivo and in vitro. BL downregulates the levels of solute carrier family 7 member 11 (SLC7A11), Ferritin heavy chain (FTH1), and glutathione peroxidase (GPX4) by inhibiting the activation and translocation of the Signal transducer and activator of transcription 3 (STAT3) from inducing Fe2+ burst, ROS and LPO accumulation, ultimately resulting in ferroptosis. This study will offer new insight into BL-induced conjunctival injury and LED-induced dry eye.

Actinic granuloma of the conjunctiva in young women.

OBJECTIVE: To report the occurrence of actinic granuloma of the conjunctiva in young women. DESIGN: Retrospective case series. PARTICIPANTS: Three eyes of 3 young women with a unilateral conjunctival mass of recent onset. METHODS: Three young women (21, 23, and 23 years of age) sought treatment for painless red masses of the conjunctiva that were thought clinically to be pingueculitis, actinic keratosis, or ocular surface squamous neoplasia (OSSN), but were diagnosed histopathologically as actinic granuloma. Special stains were performed to exclude infectious and autoimmune causes of granulomatous inflammation, followed by dermatologic work-up and systemic investigations. Diagnosis of actinic granuloma of the conjunctiva was confirmed. MAIN OUTCOME MEASURES: Patients' characteristics (age, sex, early onset), clinical presentation, same geographical location, typical histopathologic features, and lack of systemic association. RESULTS: All 3 cases were in young women with a rapid-onset conjunctival growth with conjunctival feeder vessels and intrinsic vessels; however, there was no surface keratin, and rose bengal stain results were negative. Histopathologic analysis of all 3 cases revealed elastolysis and granulomatous inflammation characterized by multinucleated giant cells, some of which displayed elastophagocytosis that was highlighted by Verhoeff-van Giesen elastic stain. There was absence of cytologic atypia of surface epithelium. Mucin stains and special stains for an infectious cause demonstrated negative results. Serologic investigations and systemic work-up results were negative, which excluded any systemic associations with this condition. This led to the final diagnoses of actinic granuloma of the conjunctiva. CONCLUSIONS: Conjunctival actinic granuloma is an underrecognized entity. We present 3 cases of this condition to highlight its occurrence in young women and the role of histopathologic examination to avoid misinterpretation of this condition. Both clinician and pathologist should consider this entity as a differential diagnosis of benign conjunctival lesions and OSSN. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Myopia, Melatonin and Conjunctival Ultraviolet Autofluorescence: A Comparative Cross-sectional Study in Indian Myopes.

Purpose: To explore the role of outdoor light exposure by estimating ocular sun exposure measured by Conjunctival Ultraviolet Autofluorescence (CUVAF) imaging and serum melatonin levels in myopes and non-myopes.Materials & Methods: Age and sex matched emmetropes and myopes (60 each) aged 10-25 years participated. Those with a history of ocular surgery or any ocular or systemic co-morbidity were excluded. Socio-demographic parameters, sun exposure questionnaires, indoor and outdoor activity profile, morning serum melatonin levels, sleep pattern, degree of myopia, ocular biometry and area of CUVAF on ultraviolet photography were noted and analyzed.Results: Mean age of myopes (18 ± 4.5 years) and emmetropes (18.5 ± 4 years) was similar (P = .523). Serum melatonin levels were significantly higher (P = .001) among myopes (89.45 pg/ml) as compared to emmetropes (52.83 pg/ml). Lifetime sun exposure was significantly lower in myopes than emmetropes (P = .0003). Area of CUVAF was inversely related to degree of myopia (P < .0001). Day time sleepiness was greater in myopes (51.7%) than emmetropes (15%) (P < .0001). There was a positive correlation between serum melatonin levels and axial length among myopes (correlation coefficient = 0.27; P = .03). Age and gender had no association with serum melatonin levels.Conclusion: This study demonstrates an inverse relationship between serum melatonin levels and degree of CUVAF in myopes. A novel link between serum melatonin, axial length and outdoor sun exposure is highlighted in the current study.

Effect of UV-absorbing Contact Lenses on Conjunctival Ultraviolet Autofluorescence.

PURPOSE: The intended purpose of UV-absorbing contact lenses is to protect the cornea and posterior ocular structures from UV-induced damage. Few studies report conjunctival effects of UV-absorbing contact lens materials. The purpose of this study was to evaluate conjunctival ultraviolet autofluorescence (UVAF) for contact lens wearers of UV-absorbing and minimally UV-absorbing materials. METHODS: Forty-four volunteers enrolled in the cross-sectional study. Three groups were recruited; non-contact lens wearers (n = 15), minimally UV-absorbing contact lens wearers (n = 15), and UV-absorbing contact lens wearers (n = 14). Ocular sun exposure was calculated using self-reported measures. Conjunctival UVAF images of temporal and nasal conjunctiva, acquired using a Nikon D7000 camera system adapted with appropriate flash and filter system, were analyzed using ImageJ. A sub-group of participants including only subjects with measurable UVAF was analyzed. RESULTS: No significant differences were present between groups found similar for age, gender, and ocular sun exposure. The area of UVAF significantly increased following lens removal for UV-absorbing contact lens wearers compared with non-contact lens wearers. Furthermore, for contact lens wearers compared with non-lens wearers, area of UVAF was significantly greater between right and left eyes (p = .04 minimally UV-absorbing, p = .01 UV-absorbing), and between nasal (p = .046 minimally UV-absorbing, p = .01 UV-absorbing), and temporal (p = .01 UV-absorbing) areas. However, no significant difference was found between contact lens wearers of the two groups. No difference was found between nasal and temporal UVAF regions during contact lens wear (p = .28) or after lens removal (p = .16) (Mann-Whitney U). CONCLUSIONS: Contact lens materials have conjunctival effects, with increased UVAF in both UV-absorbing and minimally UV-absorbing contact lens wearers compared with non-lens wearers. UV-absorbing and minimally UV-absorbing contact lens materials appear to influence nasal and temporal areas of the ocular surface equally.

Comparison of ophthalmic toxicity of light-emitting diode and organic light-emitting diode light sources.

The use of organic light-emitting diodes (OLEDs) has rapidly increased in recent years. However, the effect of OLEDs on human health has not been studied yet. We investigated morphologic and functional changes after OLEDs exposure of human ocular cells, including corneal, conjunctival, lens, and retinal pigment epithelial cells, and mouse eyes. In corneal and conjunctival epithelial cells, the levels of reactive oxygen species production and interleukin-8 expression after white light-emitting diodes (LED) exposure were significantly greater than those after OLED exposure. Although no gross morphologic changes of the eyelid or cornea were found in LED- or OLED-exposed mice, oxidative stress on ocular surface was significantly increased, and the outer nuclear layer (ONL) was significantly shorter in both light-treated groups than the control group. Moreover, ONL thickness was significantly lower in the LED group than the OLED group. The electroretinography response was significantly lower in light exposure group, and there was significant difference between LED- and OLED-treated mice. Although OLED exhibits certain ocular toxicity, it can be less toxic to eyes than LED. The higher blue-wavelength energy of LED light might be the reason for its higher toxicity relative to OLED.

Conjunctival ultraviolet autofluorescence area, but not intensity, is associated with myopia.

BACKGROUND: Conjunctival ultraviolet autofluorescence (CUVAF) has been used as a biomarker of time spent outdoors. Smaller CUVAF area is associated with myopia in southern hemisphere cohorts. Further research is required to determine if this association is replicated in northern latitudes and whether average CUVAF intensity is a valuable metric. This prospective study explored the association between myopia, CUVAF (area and intensity) and additional indicators of sun exposure (vitamin D3 and self-reported sun exposure preferences) across seasons at a location of 55° north. METHODS: Young adults (age 18-20) provided blood samples biannually (March/April and September/October) over an 18-month period (four phases) for the assessment of 25-hydroxyvitamin D (25(OH)D3 ) concentrations (liquid chromatography-tandem mass spectrometry). CUVAF (total area, average intensity) and self-reported sun exposure preferences were recorded at each phase. Axial length and corneal radius were measured. Refractive error was measured by autorefractor and spherical equivalent refraction used to classify participants into refractive groups: myopic (spherical equivalent refraction ≤ -0.50 DS) or non-myopic. RESULTS: Fifty-four participants (24 myopes, 30 non-myopes) participated. CUVAF area was negatively associated with the presence of myopia (odds ratio = 0.94, 95 per cent confidence interval = 0.90-0.98, p = 0.002). Myopes = 4.5 mm2 (interquartile range [IQR] 0.95-6.4 mm2 ), non-myopes = 7.0 mm2 (IQR = 2.0-10.7 mm2 ). No significant association was found between CUVAF intensity and refractive group (p = 0.17). There was no significant association between sun exposure preferences or serum concentration of 25(OH)D3 and refractive status (all p ≥ 0.21). CUVAF measures were not associated with ocular biometry measures (all p ≥ 0.084). CUVAF area was unaffected by season (all p ≥ 0.45) and variations in CUVAF area over the study period did not exceed the repeatability of the measurement technique. CONCLUSION: Myopia was associated with smaller areas of CUVAF indicative of less cumulative ultraviolet-B exposure. These findings suggest that CUVAF measures are a useful, non-invasive biomarker of the time spent outdoors in adults in northern hemisphere populations.

Dry eye following cataract surgery: The effect of light exposure using an in-vitro model.

PURPOSE: Cataract surgery can lead to the temporary development or worsening of dry eye symptoms. Contributing factors may include corneal incisions, agents used before, during or after surgery, light from the operating microscope, disruption of ocular surface tissues and inflammatory processes. The purpose of this study was to observe the effect of light exposure on conjunctival fibroblasts in order to determine whether light has an effect on wound healing closure, assuming that operating microscopes might have an effect on the ocular surface. METHOD: An in vitro scratch assay was performed on porcine conjunctival fibroblasts. Ten minutes of light exposure from a light microscope with a halogen bulb was performed after the scratch assay. Fibroblasts were kept in culture for 48 hours post-exposure and the wound closure rates were visualized by live/dead staining. The fibroblasts which were exposed to light were compared to those without light exposure. Cell viability was also analysed by MTT assay. RESULTS: A Slower wound closure rate was found when fibroblasts were exposed to light compared to the non-light exposed controls. Cell viability reduced by 20% with light exposure compared to controls in p3 cells (p = 0.04; however, the trend was not observed with p4 and p5 cells (p > 0.05). CONCLUSIONS: These results suggest that light exposure might be one of the possible contributory factors for dry eye after ophthalmic surgery. Further evaluation of light effects should be carried out with different ocular surface cells.

UV damage of the anterior ocular surface - microstructural evidence by in vivo confocal microscopy.

PURPOSE: To evaluate and describe the microstructural changes at the ocular surface in response to habitual ocular sun exposure, correlate them with the UV protection habits and follow their dynamics using in vivo confocal microscopy(ICM). METHODS: For a period of minimum 4 months 200 subjects (400 eyes), aged 28 ±â€¯7.3 years, were recruited with the agreement that they will spend their summer exclusively in the region of the Black Sea coast at 43 °N latitude and will be examined before and after the summer. All subjects filled in a questionnaire about habitual UV protection and were examined clinically and by ICM. RESULTS: Questionnaire results demonstrated that 83.5% (167 participants) of the subjects considered the sun dangerous for their eyes, but 78% (156 subjects) believed that there is danger exclusively during the summer period. Although no clinical changes were detected, microstructural analysis of the cornea demonstrated statistically significant (p = 0.021) decrease of the basal epithelial density - from 6167 ±â€¯151 cells/mm2 before to 5829 ±â€¯168 cells/mm2 after the summer period. Microstructural assessment of the conjunctiva demonstrated characteristic cystic lesions with dark centres and bright borders encountered in only 25 eyes(6%) before, and affecting 118 eyes(29.5%) after the summer. The total area of the cysts after the summer increased fivefold. Spearman analysis proved negative correlation between sun protection habits and number of cysts. CONCLUSION: Summer sun exposure for one season leads to clinically undetectable, microstructural changes affecting the cornea, bulbar and palpebral conjunctiva with transient, but possibly cumulative nature.

Blue light phototoxicity toward human corneal and conjunctival epithelial cells in basal and hyperosmolar conditions.

AIMS: The ocular surface is the very first barrier between the visual system and external environment. It protects the eye from the exposure to various light sources that significantly emit in blue spectrum. However, the impact of blue light on the ocular surface has been poorly explored so far. In this study, we investigated in vitro the phototoxicity of blue light illumination in human epithelial cells of the ocular surface. We worked either in basal conditions or under hyperosmolar stress, in order to mimic dry eye disease (DED) that is the most common disease involving the ocular surface. RESULTS: Corneal and conjunctival epithelial cells suffered the most from violet-blue light but also from longer-wave blue light. Exposure to blue wavebands significantly decreased cellular viability, impacted on cellular morphology and provoked reactive oxygen species (ROS) over-production. Conjunctival epithelial cell line had a greater photosensitivity than the corneal epithelial one. Hyperosmolar stress potentiated the blue light phototoxicity, increasing inflammation, altering mitochondrial membrane potential, and triggering the glutathione-based antioxidant system. INNOVATION: In human epithelial corneal and conjunctival cells of the ocular surface, we demonstrated the harmful impact of blue light on viability, redox state and inflammation processes, which was modified by hyperosmolarity. CONCLUSION: Blue light induced cell death and significant ROS production, and altered the expression of inflammatory genes and operation of the cellular defensive system. We established for the first time that hyperosmolar stress impacted phototoxicity, further suggesting that DED patients might be more sensitive to blue light ocular toxicity.

Cytoprotective effect against UV-induced DNA damage and oxidative stress: role of new biological UV filter.

The majority of chemical solar filters are cytotoxic, particularly on sensitive ocular cells (corneal and conjunctival cells). Consequently, a non-cytotoxic UV filter would be interesting in dermatology, but more especially in ophthalmology. In fact, light damage to the eye can be avoided thanks to a very efficient ocular antioxidant system; indeed, the chromophores absorb light and dissipate its energy. After middle age, a decrease in the production of antioxidants and antioxidative enzymes appears with accumulation of endogenous molecules that are phototoxic. UV radiations can induce reactive oxygen species formation, leading to various ocular diseases. Because most UV filters are cytotoxic for the eye, we investigated the anti-UV properties of Calophyllum inophyllum oil in order to propose it as a potential vehicle, free of toxicity, with a natural UV filter action in ophthalmic formulation. Calophyllum inophyllum oil, even at low concentration (1/10,000, v/v), exhibited significant UV absorption properties (maximum at 300nm) and was associated with an important sun protection factor (18-22). Oil concentrations up to 1% were not cytotoxic on human conjunctival epithelial cells, and Calophyllum inophyllum oil appeared to act as a cytoprotective agent against oxidative stress and DNA damage (85% of the DNA damage induced by UV radiations were inhibited with 1% Calophyllum oil) and did not induce in vivo ocular irritation (Draize test on New Zealand rabbits). Calophyllum inophyllum oil thus exhibited antioxidant and cytoprotective properties, and therefore might serve, for the first time, as a natural UV filter in ophthalmic preparations.