Conjunctival Ultraviolet Autofluorescence Research Articles

Could Children's Myopization Have Been Avoided during the Pandemic Confinement? The Conjunctival Ultraviolet Autofluorescence (CUVAF) Biomarker as an Answer.

The objective of this study was to evaluate the association of the presence of conjunctival ultraviolet autofluorescence (CUVAF) with the level and progression of myopia and the impact of reduced sunlight exposure during the COVID-19 pandemic confinement (PC). A retrospective observational study was carried out using three cohorts, children (9-17 years old), young adults (18-25 years old), and adults (>40 years old) with myopia (≤0.75D) and at least three annual eye examinations (before and after PC). All participants underwent an automatic objective refraction and CUVAF area analysis. All the participants filled out a questionnaire regarding lifestyle and myopia history. The 298 recruited participants showed that during the PC, children's and young adults' myopia progression rate increased on average by -0.50 and -0.30 D/year, respectively, compared with the pre-pandemic level (p < 0.0001 and p < 0.01). A significantly greater progression was observed in those with low baseline myopia compared to those with moderate or high myopia (p < 0.01). CUVAF shows its protective effect associated with outdoor activity (OA) with regard to the age of onset of myopia and mean diopters (p < 0.01). In fact, although there were no differences in the increase in diopters between children with and without CUVAF during the PC, those who had CUVAF started with lower gains (-0.3 D/year) compared to those who did not (-0.5 D/year; p < 0.05). The myopia treatments (atropine drops, Ortho-K, and MiSight® contact lenses) showed a reduction effect in myopic progression rate post-PC in comparison with non-treated children (p < 0.0001, p < 0.0001 and p < 0.01, respectively). The strict restriction of OA during PC led to the rate of myopia progression doubling among children and young adults. This progression occurred mainly in children with previously low myopia, and CUVAF, as a biomarker of OA, reflects its potential to provide benefits in the form of recommended behavioral changes to protect against the development of myopia.

Conjunctival ultraviolet autofluorescence as a biomarker of outdoor exposure in myopia: a systematic review and meta-analysis

Outdoor exposure is considered the primary modifiable risk factor in preventing the development of myopia. This effect is thought to be attributed to the light-induced synthesis and release of dopamine in the retina. However, until recent years, there was no objective quantifiable method available to measure the association between time spent outdoors and myopia. It is only recently that the conjunctival ultraviolet autofluorescence (CUVAF) area, serving as a biomarker for sun exposure, has begun to be utilized in numerous studies. To provide a comprehensive summary of the relevant evidence pertaining to the association between the CUVAF area and myopia across different geographic regions and age groups, a systematic review and meta-analysis were conducted. The search encompassed multiple databases, including MEDLINE, SCIENCE DIRECT, GOOGLE SCHOLAR, WEB OF SCIENCE, and SCOPUS, and utilized specific search terms such as "conjunctival ultraviolet autofluorescence", "CUVAF", "UVAF", "objective marker of ocular sun exposure", "myopia", "degenerative myopia", and "high myopia". The bibliographic research included papers published between the years 2006 and 2022. A total of 4051 records were initially identified, and after duplicates were removed, 49 articles underwent full-text review. Nine articles were included in the systematic review. These studies covered myopia and outdoor exposure across different regions (Australia, Europe and India) with a total population of 3615 individuals. They found that myopes generally had smaller CUVAF areas compared to non-myopes. The meta-analysis confirmed this, revealing statistically smaller CUVAF areas in myopic patients, with a mean difference of − 3.30 mm2 (95% CI − 5.53; − 1.06). Additionally, some studies showed a positive correlation between more outdoor exposure and larger CUVAF areas. In terms of outdoor exposure time, myopic patients reported less time outdoors than non-myopic individuals, with a mean difference of − 3.38 h/week (95% CI − 4.66; − 2.09). Overall, these findings highlight the connection between outdoor exposure, CUVAF area and myopia, with regional variations playing a significant role. The results of this meta-analysis validate CUVAF as a quantitative method to objectively measure outdoor exposure in relation with myopia development.

Changes in Refractive Error During Young Adulthood: The Effects of Longitudinal Screen Time, Ocular Sun Exposure, and Genetic Predisposition.

Changes in refractive error during young adulthood is common yet risk factors at this age are largely unexplored. This study explored risk factors for these changes, including gene-environmental interactions. Spherical equivalent refraction (SER) and axial length (AL) for 624 community-based adults were measured at 20 (baseline) and 28 years old. Participants were genotyped and their polygenic scores (PGS) for refractive error calculated. Self-reported screen time (computer, television, and mobile devices) from 20 to 28 years old were collected prospectively and longitudinal trajectories were generated. Past sun exposure was quantified using conjunctival ultraviolet autofluorescence (CUVAF) area. Median change in SER and AL were -0.023 diopters (D)/year (interquartile range [IQR] = -0.062 to -0.008) and +0.01 mm/year (IQR = 0.000 to 0.026), respectively. Sex, baseline myopia, parental myopia, screen time, CUVAF, and PGS were significantly associated with myopic shift. Collectively, these factors accounted for approximately 20% of the variance in refractive error change, with screen time, CUVAF, and PGS each explaining approximately 1% of the variance. Four trajectories for total screen time were found: "consistently low" (n = 148), "consistently high" (n = 250), "consistently very high" (n = 76), and "increasing" (n = 150). Myopic shift was faster in those with "consistently high" or "consistently very high" screen time compared to "consistently-low" (P ≤ 0.031). For each z-score increase in PGS, changes in SER and AL increased by -0.005 D/year and 0.002 mm/year (P ≤ 0.045). Of the three types of screen time, only computer time was associated with myopic shift (P ≤ 0.040). There was no two- or three-way interaction effect between PGS, CUVAF, or screen time (P ≥ 0.26). Higher total or computer screen time, less sun exposure, and genetic predisposition are each independently associated with greater myopic shifts during young adulthood. Given that these factors explained only a small amount of the variance, there are likely other factors driving refractive error change during young adulthood.

The relationship between outdoor exposure and myopia on university students, measured by conjunctival ultraviolet autofluorescence (CUVAF)

AbstractPurpose: The purpose of this study was to analyse whether outdoor (OD) exposure could exert a protective effect against the development of myopia and HM, in two different cohorts of university students that differ in the time of OD activities in their study programs. Moreover, CUVAF, as an objective measure of time spent outdoors, was also investigated in this cohort.Methods: A cross‐sectional observational study was carried out using two different cohorts of students, one of medical students (MS) and the other of environmental science students (ESS). All participants underwent an automatic objective refraction, axial length measurement, colour fundus photographs, and CUVAF area (BAF module on the Heidelberg Spectralis HRA + OCT). All the participants filled out a questionnaire of life style and myopia history. For all statistical analyses, corrected p values &lt; 0.05 (two‐tailed) were considered statistically significant using SPSS 20.1 Software.Results: A total of 208 participants were recruited, 156 were MS and 52 were ESS. The data showed that 66.66% of the MS were myopic versus only 50% of the ESS (p = 0.021; OR 95 = 2.03 (95% CI 1.1–3.6). With regards to OD activities, ESS spent significantly more hours per week doing OD activities than MS (p &lt; 0.0001), but with respect to near work activities, there was no significant difference between both cohorts. In this sense, it was found that high myopia MS spent significantly fewer hours outdoors than their controls (p &lt; 0.05). The degree of myopia was inversely associated with CUVAF in all university students, and a statistically significant positive correlation was observed between spherical equivalent and CUVAF (r = 0.248 [95% CI 0.094–0.390]; p = 0.001).Conclusions: The results showed that OD activities could reduce the onset and progression of myopia not only in children, but also in young adults. In addition, CUVAF represents an objective, non‐invasive biomarker of OD exposure that is inversely associated with myopia, and can be useful to follow‐up myopic patients.

Evaluating the impact of ocular UV exposure for the development for pseudoexfoliation syndrome in a South Indian population

ABSTRACT Clinical Relevance Pathophysiology of pseudoexfoliation syndrome (XFS) can be influenced by environmental factors such as solar exposure/occupational factors and genetic factors. Background The study aims to assess the association of lifetime ocular UV exposure and its impact on the risk of development of XFS. Methods All eligible subjects underwent a comprehensive ocular examination. XFS was defined as precipitates on the pupillary border, cornea, and angle of anterior chamber or lens in at least one eye without any clinical signs of glaucoma. A standardised questionnaire was administered to assess the lifetime UV exposure. Conjunctival ultraviolet autofluorescence (CUVAF) photography was taken to detect the conjunctival changes with exposure to UV radiation. Ascorbic acid concentration in the aqueous humour was measured. Results A total of 404 subjects of which 274 (controls) and 130 (XFS cases) were studied. There were 204 males (50.5%) and 200 females (49.5%).Lifetime UV exposure (OR: 1.14, 95% CI: 1.02–1.30, p: 0.032), CUVAF damage (OR: 1.03, 95% CI: 1.01–1.06, p: 0.008) and outdoor worker (OR: 1.87, 95% CI: 1.18–3.00, p: 0.008) were positively associated with XFS. Usage of spectacles (OR: 0.63, 95% CI: 0.39–0.95, p: 0.030) and ascorbic acid concentration in aqueous (OR: 0.47, 95% CI: 0.23–0.99, p: 0.038) were found to be protective against XFS. Conclusion Besides genetic factors, environmental factors such as lifetime ocular UV exposure and outdoor work are significantly associated with the risk of XFS. CUVAF can be used as a non-invasive tool to detect preclinical sun damage in outdoor workers.

Role of conjunctival ultraviolet autofluorescence device, as an indicator of ocular ultraviolet radiation exposure in pterygium and pinguecula among outdoor workers in Southern India

Background: Objective of the study was to evaluate conjunctival ultraviolet autofluorescence (CUVAF) device, as an indicator of ocular ultraviolet (UV) radiation exposure in pterygium and pinguecula among outdoor workers.Methods: Subjects above 21 years of age engaged in outdoor work were enrolled based on inclusion criteria. A standardized questionnaire was administered to assess the lifetime UV exposure and erythemal UV dose were noted from the tropospheric emission monitoring internet service (TEMIS). Autofluorescence photographs of the nasal and temporal conjunctiva were taken using CUVAF tool and were assessed for presence of damage with exposure to UV radiation. Logistic regression was done to estimate the risk.Results: A total of 229 participants, among them 205 (89.5%) were males and 24 (10.4%) were females. This included 75 (32.7%) with pterygium in one or both eyes, 69 (30.3%) with pinguecula and 85 (37.1%) normal. Median conjunctival damage in pterygium was 45.3 mm2 (IQR 35.1), in pinguecula was 17.9 mm2 (IQR 16.0) and in normal was 11.1 mm2 (IQR 25.2) demonstrating significant difference between the groups (p&lt;0.001). The conjunctival damage was positively associated with pterygium OR: 1.12 (95% CI: 1.05-1.71, p&lt;0.001) and pinguecula OR: 1.10 (95% CI: 1.07-1.49, p=0.01). Rural location, literacy status were the significant risk factors for development of pterygium with odds of 2.97 (95% CI: 1.46-6.05, p=0.003) and 4.84 (95% CI: 1.86-12.73, p=0.001) respectively.Conclusions: Increasing conjunctival damage was found to be associated with prevalent pterygium.

A Cross-Sectional Observational Study of the Relationship between Outdoor Exposure and Myopia in University Students, Measured by Conjunctival Ultraviolet Autofluorescence (CUVAF).

Myopia is the most common refractive error worldwide. This cannot be explained by genetic factors alone, therefore, environmental factors may play an important role. Hence, the main objective of this study was to analyse whether outdoor exposure could exert a protective effect against the development of myopia in a cohort of young adults and to investigate ultraviolet autofluorescence (CUVAF), as a biomarker of time spent outdoors. A cross-sectional observational study was carried out using two cohorts. A total of 208 participants were recruited, 156 medical students and 52 environmental science students. The data showed that 66.66% of the medical students were myopic, while 50% of the environmental science students were myopic (p = 0.021). Environmental science students spent significantly more hours per week doing outdoor activities than medical students (p < 0.0001), but there was no significant difference with respect to near work activities between them. In both cohorts, the degree of myopia was inversely associated with CUVAF, and a statistically significant positive correlation was observed between spherical equivalent and CUVAF (Pearson’s r = 0.248). In conclusion, outdoor activities could reduce the onset and progression of myopia not only in children, but also in young adults. In addition, CUVAF represents an objective, non-invasive biomarker of outdoor exposure that is inversely associated with myopia.

Prevalence and Risk Factors of Myopia in Young Adults: Review of Findings From the Raine Study.

Myopia tends to develop and progress fastest during childhood, and the age of stabilization has been reported to be 15–16 years old. Thus, most studies on myopia have centered on children. Data on the refractive error profile in young adulthood — a time in life when myopia is thought to have stabilized and refractive error is unaffected by age-related pathology such as cataract — are limited. The Raine Study has been following a community-based cohort of young adults representative of the general Western Australia population since their prenatal periods in 1989–1991, with eye examinations performed when participants were 20 and 28 years old. At 20 years old, prevalence of myopia in the cohort was 25.8%. Using long-term trajectory of serum vitamin D levels and conjunctival ultraviolet autofluorescence (CUVAF) area to objectively quantify sun exposure, the Raine Study confirmed a negative relationship between time spent outdoors and myopia prevalence. However, prospective studies are required to determine the amount of CUVAF area or serum vitamin D levels associated with time duration. Combining data from the Raine Study and several other cohorts, Mendelian randomization studies have confirmed a link between myopia and a genetic predisposition toward higher education. Several novel potential associations of myopia or ocular biometry were investigated, including fetal growth trajectory, which was found to be significantly associated with corneal curvature at 20 years. By age 28, myopia prevalence had increased to 33.2%. Between 20 and 28 years old, myopia progressed and axial length elongated, on average, by −0.041D/year and 0.02 mm/year, respectively. Smaller CUVAF area at follow-up, female sex, and parental myopia were significant risk factors for myopia incidence and progression between 20 and 28 years. Given the limited research in young adults, further investigations are warranted to confirm the Raine Study findings, as well as identify novel genetic or environmental factors of myopia incidence and progression in this age group.

Incidence and Progression of Myopia in Early Adulthood

Myopia incidence and progression has been described extensively in children. However, few data exist regarding myopia incidence and progression in early adulthood. To describe the 8-year incidence of myopia and change in ocular biometry in young adults and their association with the known risk factors for childhood myopia. The Raine Study is a prospective single-center cohort study. Baseline and follow-up eye assessments were conducted from January 2010 to August 2012 and from March 2018 to March 2020. The data were analyzed from June to July 2021. A total of 1328 participants attended the baseline assessment, and 813 participants attended the follow-up assessment. Refractive information from both visits was available for 701 participants. Participants with keratoconus, previous corneal surgery, or recent orthokeratology wear were excluded. Participants' eyes were examined at ages 20 years (baseline) and 28 years. Incidence of myopia and high myopia; change in spherical equivalent (SE) and axial length (AL). A total of 516 (261 male [50.6%]) and 698 (349 male [50.0%]) participants without myopia or high myopia at baseline, respectively, were included in the incidences analyses, while 691 participants (339 male [49%]) were included in the progression analysis. The 8-year myopia and high myopia incidence were 14.0% (95% CI, 11.5%-17.4%) and 0.7% (95% CI, 0.3%-1.2%), respectively. A myopic shift (of 0.50 diopters [D] or greater in at least 1 eye) occurred in 261 participants (37.8%). Statistical significance was found in longitudinal changes in SE (-0.04 D per year; P < .001), AL (0.02 mm per year; P <.001), and lens thickness (0.02 mm per year; P < .001). Incident myopia was associated with self-reported East Asian vs White race (odds ratio [OR], 6.13; 95% CI, 1.06-35.25; P = .04), female vs male sex (OR, 1.81; 95% CI, 1.02-3.22; P = .04), smaller conjunctival ultraviolet autofluorescence area (per 10-mm2 decrease, indicating less sun exposure; OR, 9.86; 95% CI, 9.76-9.97; P = <.009), and parental myopia (per parent; OR, 1.57; 95% CI, 1.03-2.38; P = <.05). Rates of myopia progression and axial elongation were faster in female participants (estimate: SE, 0.02 D per year; 95 % CI, 0.01-0.02 and AL, 0.007 mm per year, 95 % CI, 0.00.-0.011; P ≤ .001) and those with parental myopia (estimate per parent: SE, 0.01 D per year; 95% CI, 0.00-0.02 and AL, 95% CI, 0.002-0.008; P ≤ .001). Education level was not associated with myopia incidence or progression. These findings suggest myopia progression continues for more than one-third of adults during the third decade of life, albeit at lower rates than during childhood. The protective effects of time outdoors against myopia may continue into young adulthood.

Conjunctival ultraviolet autofluorescence area decreases with age and sunglasses use

BackgroundConjunctival ultraviolet autofluorescence (CUVAF) is a method of detecting conjunctival damage related to ultraviolet radiation exposure. In cross-sectional studies, CUVAF area is positively associated with self-reported time spent outdoors and...

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

ABSTRACT 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.

Role of Conjunctival Ultraviolet Autofluorescence in Ocular Surface Squamous Neoplasia

Objective: To evaluate the adjunctive role of conjunctival autofluorescence in the management of ocular surface squamous neoplasia (OSSN). Materials and Methods: Seventeen patients with clinically diagnosed OSSN were included. Morphological characteristics, type of OSSN, and autofluorescence photographs of the lesion were captured. Presence and area of conjunctival ultraviolet autofluorescence (CUVAF) were the main outcome measures. Results: Overall, 17 patients with 15 (88%) primary and 2 (12%) recurrent OSSN were included. Common locations were temporal (n = 10), nasal (n = 5), and diffuse variety (n = 2). Morphologically, there were 4 (22.2%) nodular, 4 (22.2%) leucoplakic, 3 (16.7%) gelatinous, and 1 (5.5%) each of papillary, nodulo-ulcerative, and diffuse variety. Mixed morphology was present in 4 eyes (22.2%). Sixteen of 18 eyes (88.9%) with OSSN displayed autofluorescence on CUVAF images. The mean area of CUVAF was 15.82 mm² (10.77–19.59 mm²). Autofluorescence was reported in 8 eyes (44.4%) which had negative reports on impression cytology. Conclusions: Conjunctival autofluorescence was seen in the majority of cases with OSSN, in spite of negative cytology reports. Our study demonstrates that CUVAF may serve as an effective ancillary, non-invasive, and resource-friendly tool for supplementing the clinical diagnosis of OSSN, especially in diffuse and recurrent lesions that are not amenable to surgical intervention.

Conjunctival Ultraviolet Autofluorescence as a Measure of Riboflavin and Ultraviolet and Accelerated Cross-Linking Exposure in Keratoconic Patients.

Purpose: The study was performed to analyze the prevalence of the conjunctival ultraviolet autofluorescence (CUVAF) area in keratoconic eyes and changes caused by UVA-irradiation as a component of accelerated corneal cross-linking (aCXL). Methods: The study group involved 20 keratoconic patients subjected to aCXL surgery in one eye. The comparative group consisted of 111 age- and sex-matched patients with healthy corneas. The images of the anterior segment in both patient groups were taken using a Coroneo camera. In the study group the photos were taken before and immediately after the surgery, and 7 and 30 days following the procedure. Results: Nasal and temporal autofluorescence area (AN+T) were significantly smaller in a keratoconic patients group compared to control group (p = 0.0001). Patients with the third stage of keratoconus had significantly higher AN+T (p = 0.0277) compared with individuals with lower stage keratoconus. No statistically significant CUVAF changes were observed after the aCXL procedure. In keratoconic patients with primary CUVAF undergoing aCXL, a temporary fast enlargement of the autofluorescence area was observed. Conclusions: The eyes undergoing the aCXL procedure showed no difference in the size of the CUVAF area but such patients should be in strict follow-up in order to reveal UV-related ocular surface diseases.

Has the Sun Protection Campaign in Australia Reduced the Need for Pterygium Surgery Nationally?

ABSTRACT Background The Slip! Slop! Slap! Sunsmart safety campaign was an Australian initiative implemented in the 1980s. To assess this campaign’s effect on pterygium, we examined the rate of pterygium surgery across Australia and described the prevalence and associations of pterygium in Perth, Australia’s sunniest capital city. Methods The rate of pterygium surgery was examined using Australian Medicare data. A cross-sectional analysis of the Generation 1 (Gen1) cohort of the Raine Study was performed to investigate the prevalence of pterygium in Perth. We investigated the association between pterygium and conjunctival ultraviolet autofluorescence (CUVAF) area, an objective biomarker of sun exposure, and demographics and health variables derived from a detailed questionnaire. Results Between 1994 and 2017, the rate of Medicare funded pterygium surgery in Western Australia fell 11%, well below the national average decline of 47%. Of the 1049 Gen1 Raine Study participants, 994 (571 females; mean age 56.7 years, range = 40.9–81.7) were included in the analysis. The lifetime prevalence of pterygium was 8.4% (n = 83). A higher prevalence of pterygium was associated with outdoor occupation (p-trend = 0.007), male sex (p-trend 0.01) and increasing CUVAF area (p-value <0.001). Conclusions The effect of Australia’s Slip! Slop! Slap! Sunsmart safety campaign on pterygium been mixed. Since 1994, the rate of private pterygium surgery has declined significantly in all Australian states except Western Australia. Perth, Western Australia, has the highest pterygium prevalence of any mainland-Australian cohort. Higher CUVAF area, male sex, and outdoor occupation were associated with an increased risk of pterygium.

Effect of UV-absorbing Contact Lenses on Conjunctival Ultraviolet Autofluorescence

ABSTRACT 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.

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

BackgroundConjunctival 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.MethodsYoung 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.ResultsFifty‐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.ConclusionMyopia 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.

Seasonal Effect on Ocular Sun Exposure and Conjunctival UV Autofluorescence.

To evaluate feasibility and repeatability of measures for ocular sun exposure and conjunctival ultraviolet autofluorescence (UVAF), and to test for relationships between the outcomes. 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. 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. 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.

Photodamage of the anterior eye surface from UV radiation. Adequate methods of protection

Introduction: Ultraviolet (UV) light is electromagnetic radiation with a wavelength from 400 nm to 10 nm, occupying the light spectrum between the visible light and the X-rays. Essential for the normal development of the body in moderate, excessive exposure to UV radiation can lead to many diseases. Absorption of UV radiation from the eye is in correlation with the wavelength, and most of it is absorbed by the cornea and the conjunctiva. To objectively measure the UV radiation reaching the eye, the method of conjunctival autofluorescence is developed. Purpose: To present our first data and impressions of the sun protection habits and conjunctival ultraviolet autofluorescence (UVAF) of a randomly selected target group. Materials and Methods: A prospective, randomized study, including photographs of 123 subjects (246 eyes) and 200 questionnaires. Results: Results are based on the study of 123 subjects (246 eyes). Each eye is documented in three pictures - eye in first position, temporal gaze (documenting nasal part of the limbus) and nasal gaze (documenting temporal part of the limbus). Results were analyzed with specialized software [14], [15] and show that 83 persons (67.48%) have conjunctival autofluorescence, as women prevail (women n=47 persons, men n=36 persons). The participants in the study were aged between 5 and 88 years (average age=39). The area of conjunctival UVAF tends to increase with (Norfolk Islands Eye Study - NIES). No correlation between intensive sun exposure (resp. UV radiation) and a sharp increase in the dimensions of the UVAF zone is established, suggesting a chronic damage, in support of which is the demonstrative eye damage in people with high-risk occupations (associated with electric welding, lifeguards and other outdoor occupations). Insufficient sun protection habits and incompetence about the UV radiation are documented and analyzed with the questionnaire. 87% of the surveyed believe that there is a risk of UV damage only in the summer. A significant percentage (55%) do not pay attention to the special protective equipment such as umbrellas and caps Conclusions: The survey results are based on the thesis, that conjunctival UV autofluorescence is an objective marker of UV exposure. In 83 of the 123 subjects (67.48 %), there is evidence of conjunctival autofluorescence. As age increases, the area and the intensity of UVAF also increase, assuming that the area corresponds to a chronic damage. The degree of damage correlates to a large extent to the bad sun protection habits demonstrated in the questionnaire.

Quantification of sun-related changes in the eye in conjunctival ultraviolet autofluorescence images.

Quantification of sun-related changes in conjunctival ultraviolet autofluorescence (CUVAF) images is a subjective and tedious task, in which reproducibility of results is difficult. Thus, we have developed a semiautomatic method in MATLAB(®) to analyze CUVAF images retrospectively. The algorithm was validated on 200 images from 50 randomly selected participants from the Western Australian Pregnancy Cohort (Raine) study 20-year follow-up assessment, in which CUVAF area measurements were available from previous manual analysis. Algorithm performance was compared to manual measurements and yielded better than 95% correspondence in both intra- and interobserver agreement. Furthermore, the semiautomatic method significantly reduced analysis time by 50%.

The use of conjunctival ultraviolet autofluorescence (CUVAF) as a biomarker of time spent outdoors.

Conjunctival ultraviolet autofluorescence (CUVAF) has been used in previous Southern Hemisphere myopia research as a marker for time spent outdoors. The validity of CUVAF as an indicator of time spent outdoors is yet to be explored in the Northern Hemisphere. It is unclear if CUVAF represents damage attributed to UV exposure or dry eye. This cross-sectional study investigated the association between CUVAF measures, self-reported time spent outdoors and measures of dry eye. Participants were recruited from University staff and students (n=50, 19-64years; mean 41). None were using topical ocular medications (with the exception of dry eye treatments). Sun exposure and dry eye questionnaires (Ocular Surface Disease Index and McMonnies) were completed by the participant. Dryness was also assessed using slit lamp biomicroscopy and invasive tear break up time. Images of the temporal and nasal conjunctiva from the right and left eye were captured using a bespoke photography system. The total CUVAF area, average CUVAF pixel intensity per mm(2) and total CUVAF pixel intensity were analysed using MATLAB R2013a (The MathWorks Inc). Of the 50 participants, 42% were classified as having dry eye. Self-reported sunglasses use was negatively associated with all CUVAF measures (Kruskal Wallis total CUVAF area, p=0.04, ptrend =0.03, average CUVAF pixel intensity p=0.02, ptrend =0.02, total CUVAF pixel intensity: p=0.04, ptrend =0.02). Time spent outdoors was positively associated with all CUVAF measures (Spearman's correlation coefficients, total CUVAF area: r=0.37, p=0.01, average CUVAF pixel intensity: r=0.36, p=0.01, total CUVAF pixel intensity: r=0.37, p=0.01) and remained significant when sunglasses use was controlled for (partial correlation, total CUVAF area: r=0.32, p=0.03, average CUVAF pixel intensity: r=0.39, p=0.01, total CUVAF pixel intensity: r=0.39, p=0.03). Neither CUVAF area nor intensity measures were associated with any dry eye measure (Ocular Surface Disease Index: all p≥0.41, corneal staining: all p≥0.38, McMonnies: all r≤0.09 all p≥0.52, slit lamp biomicroscopy: all r≤0.20 all p≥0.17, invasive tear break up time: all r≤-0.07 all p≥0.31). CUVAF area and intensity were not associated with clinical measures of dry eye. Greater CUVAF area and intensity were associated with wearing sunglasses less frequently and spending more time outdoors. If sunglass wear is accounted for, CUVAF may be a useful biomarker of time spent outdoors in future myopia studies.