Abstract Almost half the patients who undergo laser in situ keratomileusis (LASIK) experience dry eye following the procedure. However, the etiology of LASIK-induced dry eye is unclear. The purpose ...of this review is to examine and summarize the current evidence for the etiology of LASIK-induced dry eye, with a focus on ocular surface sensitivity and corneal innervation. Evidence suggests that the alteration of corneal nerves after LASIK is the most likely cause of the subjective symptoms of LASIK-induced dry eye, even though corneal sensitivity and the clinical indicators of dry eye return to apparently normal values within a year due to the partial recovery of the corneal nerve plexus. The hypothesis is explored that dry eye symptoms following LASIK may result from abnormal sensation due to LASIK-induced corneal neuropathy. Other factors, such as alterations in conjunctival goblet cell density, might also contribute to the symptoms and signs of LASIK-induced dry eye. Inter-relationships between nerve morphology, tear neuropeptide levels and dry eye require further investigation. A better understanding of this phenomenon may result in improved management of post-LASIK dry eye.
Purpose: Smartphone use is now ubiquitous and is associated with a range of ocular and visual symptoms. However, little is known about the etiology of the symptoms which accompany smartphone use and ...the relative contribution of accommodation/vergence versus that of the ocular surface and of blinking. This study examined the effects of 60 min reading on a smartphone on ocular symptoms, binocular vision, tear function, blinking and working distance.
Methods: Twelve young adults (18-23 years; 9F:3M) with normal vision and without dry eye, or major accommodative/binocular vision disorders, completed this pilot study. Participants read a novel on a smartphone for 60 min and the following were measured before and after the reading task: eye strain and ocular surface symptoms, non-invasive tear break-up time (NIBUT), lipid layer appearance, tear meniscus height, horizontal fixation disparity, binocular accommodative facility. Spontaneous blink rate and amplitude were counted every 10 min, and viewing distance was measured at the same timepoints. Pre- and post-task comparisons were made using Wilcoxon signed-rank test and changes during the task were assessed using Friedman test. Associations were examined using Spearman's correlation.
Results: Eyestrain symptoms and ocular surface symptoms increased after smartphone use, specifically comfort, tiredness and sleepiness items (p ≤ .02). Binocular accommodative facility decreased from a median of 11.3 (IQR 6.6) cycles/min pre-task to 7.8 (2.5) cycles/min post-task (p = .01), but there was no significant change in fixation disparity or working distance. There were no changes in NIBUT, lipid layer or tear meniscus height. Number of incomplete blinks per minute increased from a median of 6 blinks at 1 min to 15 at 60 min (p = .0049). Total blink rate (complete plus incomplete blinks) gradually increased over time, but this trend was not significant (p = .08). A greater increase in incomplete blinks over 60 min of reading was associated with worsening of the overall ocular surface symptoms score (ρ = −0.65, p = .02) and of the tiredness item (ρ = 0.70, p = .01).
Conclusions: Extended use of smartphones appears to have important implications for ocular surface health and binocular function.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
3.
TFOS DEWS II Sex, Gender, and Hormones Report Sullivan, David A.; Rocha, Eduardo M.; Aragona, Pasquale ...
The ocular surface,
July 2017, 2017-Jul, 2017-07-00, 20170701, Letnik:
15, Številka:
3
Journal Article
Recenzirano
One of the most compelling features of dry eye disease (DED) is that it occurs more frequently in women than men. In fact, the female sex is a significant risk factor for the development of DED. This ...sex-related difference in DED prevalence is attributed in large part to the effects of sex steroids (e.g. androgens, estrogens), hypothalamic-pituitary hormones, glucocorticoids, insulin, insulin-like growth factor 1 and thyroid hormones, as well as to the sex chromosome complement, sex-specific autosomal factors and epigenetics (e.g. microRNAs).
In addition to sex, gender also appears to be a risk factor for DED. “Gender” and “sex” are words that are often used interchangeably, but they have distinct meanings. “Gender” refers to a person’s self-representation as a man or woman, whereas “sex” distinguishes males and females based on their biological characteristics. Both gender and sex affect DED risk, presentation of the disease, immune responses, pain, care-seeking behaviors, service utilization, and myriad other facets of eye health.
Overall, sex, gender and hormones play a major role in the regulation of ocular surface and adnexal tissues, and in the difference in DED prevalence between women and men. The purpose of this Subcommittee report is to review and critique the nature of this role, as well as to recommend areas for future research to advance our understanding of the interrelationships between sex, gender, hormones and DED.
•Density, distribution and morphology of corneal epithelial dendritic cells (CEDC) do not differ in established contact lens wearers.•Reduced CEDC density in the corneal centre observed in ...orthokeratology lens wear requires confirmation in a larger group.•CEDC in the central cornea were similar in density and morphology to CEDC cells in the mid-peripheral cornea.•A lower ratio of central relative to mid-peripheral density of CEDC occurs with younger age.•A relatively lower density of CEDC in the corneal centre vs mid-periphery in younger patients may reflect a more naive immune status.
Contact lens wearers aged 15–25 years are at higher risk of corneal inflammation, yet little is known about corneal inflammatory state in this group. Previous investigations show density of corneal epithelial dendritic cells (CEDC) may increase with contact lens wear. However, it is not known how corneal distribution or morphology of CEDC alters with lens wear or whether these markers are affected by age. This study characterised CEDC in adolescent and young adult contact lens wearers to determine effects of contact lens wear and age on CEDC density, distribution and morphology.
Forty participants (20 contact lens wearers, 20 healthy non-wearers; age 16–36 years; 16M:24F) completed this pilot study. Corneal images were captured using in vivo confocal microscopy (HRTII, Rostock). CEDC were manually counted in a 1 mm2 area of the central and mid-peripheral cornea, and ratio of central to midperipheral density was calculated. CEDC morphology and dendrite length were graded. Differences between groups and between regions, and associations with age were examined. Significance was determined at P < 0.05.
A lower ratio of central to mid-peripheral CEDC density was found with younger age (ρ = 0.42, P = 0.01). CEDC morphology was not associated with age or contact lens wear. CEDC density in the mid-peripheral cornea was higher in soft lens wearers than non-wearers (P = 0.04), but central density did not differ. CEDC density and morphology were not significantly different between centre (median density 11 cells/mm2, range 0–120) and mid-periphery (10 cells/mm2, 0–58).
Density, distribution and morphology of CEDC do not differ in established contact lens wearers. A relatively lower density of CEDC in the central cornea of younger patients may allude to a more naive immune status in this group and warrants further study. Decreased central CEDC density identified in orthokeratology lens wear requires confirmation in a larger group.
The aim of the study was to compare the distribution of corneal and conjunctival epithelial dendritic cells (DCs) in vernal keratoconjunctivitis (VKC), allergic conjunctivitis (AC), and non-allergic ...controls to examine if the allergy type causes differences in immune cell activation. The prospective study included 60 participants: 20 with VKC, 20 with AC, and 20 non-allergic controls. In vivo confocal microscopy was performed on the right eye. The locations scanned included the corneal centre, inferior whorl, corneal periphery, corneal limbus, and bulbar conjunctiva. The DCs were counted manually, and their morphology was assessed for the largest cell body size, the presence of dendrites, and the presence of long and thick dendrites. The DC density was higher in VKC and AC compared to non-allergic group at all locations (p ≤ 0.01) except at the inferior whorl. The DC density in VKC participants was significantly higher than in AC at the limbus (p < 0.001) but not at other locations. Both the AC and the VKC group had larger DC bodies at the corneal periphery and limbus compared to the non-allergic group (p ≤ 0.03). The study found a higher proportion of participants with DCs exhibiting long dendrites at both the corneal periphery in AC (p = 0.01) and at the corneal centre, periphery, and limbus in VKC, compared to the non-allergic group (p ≤ 0.001). In conclusion, a higher DC density at the limbus may be a marker of more severe VKC. DCs with larger cell bodies and a greater proportion of participants with DCs displaying long dendrites can be potential markers to differentiate allergy from non-allergy, and more severe forms of allergy from milder forms.
Abstract Purpose To investigate changes in corneal subbasal nerve fiber density and orientation during a 3-month orthokeratology (OK) lens wear period and their relationship with concurrent changes ...in corneal sensitivity. Methods Sixteen subjects wore overnight OK lenses for 90 days and were assessed at baseline, Day 30, and Day 90. Nerve images at the corneal apex and temporal mid-periphery were captured from the right eye only using in vivo confocal microscopy and analyzed to calculate nerve fiber density (NFD) and global nerve fiber orientation (GNFO). Corneal sensitivity was measured using the Cochet-Bonnet aesthesiometer at similar corneal locations. Control groups of non-lens (NL) wearing and conventional rigid gas-permeable (GP) lens-wearing subjects were also examined. Results Significant changes in NFD, GNFO and corneal sensitivity were observed during OK lens wear over the study period. In the central cornea, both NFD and corneal sensitivity decreased by Day 30, with further reductions at Day 90. Reduced NFD was associated with reduced corneal sensitivity. In the mid-peripheral cornea only, GNFO was rotated in a clockwise direction at Day 30, with further rotation at Day 90. Corneal sensitivity reduction plateaued by Day 30. In the GP lens-wearing subjects, only corneal sensitivity decreased by Day 30 at both corneal locations. No changes were observed in the NL control subjects. Conclusions Alterations in corneal nerve morphology occur rapidly with commencement of OK lens wear and appear to underpin functional sensitivity loss. Nerve fiber orientation can provide a useful index for changes in corneal nerve morphology.
PURPOSE OF REVIEWThe rising prevalence of allergy and of allergic rhino-conjunctivitis is associated with changes in modern lifestyle. The current period of rapid development and consequent ...urbanization and migration, coupled with changes in climate, is facilitating a growth in rates of allergy.
RECENT FINDINGSAlterations to indoor and outdoor environments resulting from urbanization, industrialization, and climate change have significant implications for the prevalence and management of allergic rhino-conjunctivitis. Rising temperatures, precipitation and more extreme weather enable longer pollen seasons and greater viability of indoor and outdoor moulds and result in increased exposure to (and allergenic potential of) these aeroallergens. Outdoor air pollution is a major risk factor for rhino-conjunctivitis; key contributors are fuel combustion and dust storms because of changes in land-use and development. Further studies are needed to recognize and understand sources of indoor pollution including phthalates.
SUMMARYA better understanding of the role of environmental aeroallergens in allergic rhino-conjunctivitis is important to aid future management of allergic conjunctivitis. Strategies such as region-specific modelling of aeroallergens (pollens, air pollution) are required to predict and thus prevent exposure and to better inform appropriate childhood exposure and minimize lifelong effects.
Smartphone and tablet use in Australia and worldwide is reaching saturation levels and associated visual and ocular discomfort such as headaches, eyestrain, dry eyes and sore eyes are widespread. ...This review synthesises the available literature and considers these symptoms in the context of a binocular vision and/or ocular surface aetiology. Eye discomfort with smartphones and tablets is discussed alongside similar symptoms reported with desktop computer use. Handheld devices differ from computers in viewing position and distance, screen size and luminance, and patterns of use. Accommodation is altered with handheld device use, with increased lag and decreased amplitude. Smartphone and tablet use results in reduced fusional convergence and possibly a receded near point of convergence. This is similar to what happens with computer use. Findings related to blink rate with smartphone and tablet use are contradictory, perhaps due to the influence of task difficulty, and there is limited evidence related to blink amplitude. Reduced blink rate and amplitude are consistently reported with computer use. Use of handheld digital devices, like computers, may adversely impact tear stability. There is insufficient evidence to support the impact of handheld devices on tear volume, although this is reduced with computer use. The available literature does not conclusively link eye and visual discomfort symptoms reported with handheld digital devices, with changes in binocular vision, blinking or ocular surface. However, there is a gap in our understanding of symptoms which occur with smartphone and tablet use in the context of how these devices are used. In addition, studies are required in high users such as teenagers, and in patients with dry eye or accommodative/binocular vision anomalies, all of whom may have a higher risk of symptoms. A better understanding of symptom aetiology can guide clinical advice to minimise adverse impacts on visual and ocular surface health and discomfort.
Smartphone use by children is rising rapidly, but its ocular surface impact is unknown. This study examined the effect of smartphone use on blinking, symptoms, and tear function in children.
...Prospective intervention study where 36 children aged 6-15years (14 M:22 F) played games on a smartphone continuously for one hour. Symptoms (SANDE, IOSS, NRS) and tear film (lipid layer thickness, tear secretion, stability) were assessed before and after gaming. Blink rate and interblink interval were measured in situ using an eye tracking headset, before (during conversation) and continuously throughout gaming. Symptoms and tear film changes were examined using paired t-tests. Changes in blinking throughout one hour were examined using repeated measures ANOVA, post-hoc comparisons with Bonferroni correction. Associations examined using Pearson bivariate correlation. Significance level was 0.05.
Symptoms worsened following one hour smartphone gaming (SANDE + 8.2units, p = 0.01; IOSS + 1.3units, p < 0.001; NRS-average +6.3units, p = 0.03; NRS-comfort +7.6units, p = 0.04; NRS-tiredness +10.1units, p = 0.01), but tear film remained unchanged. Blink rate reduced from 20.8 blinks/min to 8.9 blinks/min (p < 0.001) and interblink interval increased from 2.9 s to 8.7 s (p = 0.002) within the first minute of gaming relative to baseline conversation, and this effect remained unchanged throughout one hour of gaming.
Smartphone use in children results in dry eye symptoms and immediate and sustained slowing of blinking, with no change in tear function evident up to one hour. Given the ubiquitous use of smartphones by children, future work should examine whether effects reported herein persist or get worse over a longer term causing cumulative damage to the ocular surface.
To determine tear neuropeptide levels in contact lens wearers and non-wearers, and to examine relationships with indices of corneal innervation, tear function, and ocular discomfort.
A ...cross-sectional, single-visit, investigator-masked pilot study. Assessments included Ocular Comfort Index (OCI), central and mid-peripheral corneal nerve density and morphology (HRT-Rostock), corneal sensitivity (Cochet-Bonnet aesthesiometer), tear Substance P and calcitonin gene-related peptide (CGRP) concentration (ELISA), in situ tear osmolarity (TearLab), tear secretion (Phenol Red Thread), and noninvasive tear break-up time (NITBUT; Keeler Tearscope). Groups were compared using independent t-test or Mann-Whitney U test, and regional differences assessed using paired t-tests. Associations were analyzed using Pearson or Spearman correlation. Significance was determined at P < .05.
Twenty contact lens wearers (7M:13F, 32 ± 5 years) and 20 non-wearers (7M:13F, 31 ± 5 years) completed the study. OCI score was numerically higher in lens wearers (32.27 ± 5.33) than non-wearers (27.66 ± 9.94). Tear osmolarity was higher 298.0 (IQR 291.0-309.8) vs. 288.5 (282.3-298.3) mOsmol/L; P = .01 whereas NITBUT was lower (9.8 ± 3.4 vs. 13.8 ± 5.6 s; P = .01) in lens wearers compared with non-wearers. Tear neuropeptide concentrations were not different between groups Substance P 4.29 ng/ml (IQR 1.57-6.05), CGRP 14.89 ng/ml (5.08-59.26), and there were no differences in nerve morphology or ocular surface sensitivity. Higher nerve density, interconnections, and tortuosity were observed in the central cornea than mid-peripherally (P < .05). OCI score was moderately associated with nerve tortuosity (r = 0.42, P = .01). CGRP was associated with central nerve density (ρ = 0.38, P = .02), as was tear secretion (r = -0.37, P = .02). Nerve interconnections were strongly associated with corneal sensitivity (ρ = 0.64, P < .001).
Relationships were demonstrated between nerve density, tear CGRP, and corneal sensitivity. Markers of corneal neurobiology and sensory function do not appear to be altered in contact lens wear despite worse tear function (osmolarity and stability) in lens wearers. This suggests that mechanisms other than overt changes in corneal innervation regulate tear function during lens wear. The relationship between nerve tortuosity and ocular discomfort requires elucidation.
