The Bull's Eye Pattern of the Tear Film in Humans during Visual Fixation on En-Face Optical Coherence Tomography

Evaluation of the Tear Meniscus Using Optical Coherence Tomography in Meibomian Gland Dysfunction

INTRODUCTION

This study aimed to evaluate tear meniscus parameters in meibomian gland dysfunction (MGD) using optical coherence tomography and ImageJ software.

METHODS

We enrolled 66 eyes of 66 participants and measured tear meniscus parameters, including height, depth, turbidity, and percentage area occupied by particles (PAOP) in the meniscus in the MGD and control groups.

RESULTS

Tear meniscus turbidity and PAOP were significantly higher in the MGD group, but tear meniscus height (TMH) and depth (TMD) did not differ significantly between groups. Tear meniscus turbidity and PAOP were positively correlated with each other and ocular surface parameters, including OSDI and ocular surface staining scores.

CONCLUSION

Tear meniscus turbidity and PAOP were higher in the MGD group than in the control group; therefore, they can be used as significant non-invasive parameters in the prediction of MGD. TMH and TMD did not differ significantly between groups.

The Influence of Eyelid Position and Environmental Conditions on the Corneal Changes in Early Postmortem Interval: A Prospective, Multicentric OCT Study

In the current study, using portable optical coherence tomography, we evaluated 46 corneas of 23 individuals in a multicenter setting during the first 17 h after death. Twenty-three eyes were kept open, and twenty three were kept closed. Furthermore, the experiment was carried out for 12 samples in summer and 11 in winter. Our data show that postmortem corneal alterations largely depend on the phenomena of dehydration (in particular in open eyes) and swelling of the stroma in closed eyes, probably due in the first phase to hypoxia/anoxia and subsequently to the passage by osmosis of the aqueous humor from the anterior chamber to the corneal tissue. Our findings could have significant repercussions in forensic pathology for estimating the postmortem interval and transplantation to optimize the conservation of the tissue before the explant.

The clinical features and the factors affecting visual prognosis in pediatric open-globe ınjuries

PURPOSE

To investigate clinical features and factors affecting visual prognosis after pediatric open-globe injuries.

METHODS

Retrospective study of 223 children with open-globe injury was conducted. Children with final logMAR visual acuity (LVA) > 0.70 were determined as poor-vision group (group 1, n = 108) and those with final LVA ≤ 0.70 as good-vision group (group 2, n = 115). Demographic characteristics (age, gender, and damaged eye), time between trauma and surgery, ocular trauma score (OTS), follow-up time, injury size, initial and final visual acuity levels, injury type (penetrating injury, globe rupture, perforating injury, and intraocular foreign body injury), injury localization (zone 1 = within the corneal and/or limbal area, zone 2 = within the scleral area extending 5 mm back from the limbus, and zone 3 = within the area posterior to zone 2), injury cause [metal objects (fork, knife, needle), broken glass, blunt objects (ball, punch), pen-pencil, and unidentified objects], and accompanying ocular findings of the groups were detected, and comparisons were done. Additionally, effects of age, time between trauma and surgery, OTS, injury size, follow-up time, initial LVA, injury type, and injury zone on final LVA were analyzed in both groups.

RESULTS

Mean age was 9.1 ± 2.0 years. There were 151 males and 72 females. Compared to group 1, group 2 had better initial and final visions (1.21 ± 0.26 vs 0.60 ± 0.28, p < 0.001 for initial LVA; 1.00 ± 0.32 vs 0.30 ± 0.13, p < 0.001 for final LVA), greater OTS (1.72 ± 0.53 vs 3.73 ± 0.61, p = 0.025), and smaller injury size (10.4 ± 3.5 vs 5.8 ± 2.4 mm, p = 0.002). Globe rupture (p = 0.015) and relative afferent pupillary defect (RAPD) (p = 0.037) were higher in group 1, while penetrating injury (p = 0.044), zone 1 involvement (p = 0.038), and metal object injury (p = 0.041) were higher in group 2. Based on multivariate analysis, the presences of globe rupture (p = 0.024) and RAPD (p = 0.035), the involvement without zone 1 (p = 0.042), and the injury without metal object (fork, knife, needle) (p = 0.046) were associated with poor final vision. Final LVA (for group 1 and group 2) was negatively correlated with OTS (r =  - 0.398, p = 0.037; r =  - 0.369, p = 0.040), while positively correlated with injury size (r = 0.412, p = 0.031; r = 0.318, p = 0.046) and initial LVA (r = 0.335, p = 0.043; r = 0.402, p = 0.034).

CONCLUSION

In our study, poor prognostic factors affecting final vision were low OTS, poor initial vision, the presences of globe rupture and RAPD, the large injury size, the involvement without zone 1, and the injury without metal object (fork, knife, needle).

Short Tear Breakup Time Could Exacerbate the Progression of Presbyopia in Women

Purpose

The contributory factors and symptoms for presbyopia progression have not been fully determined. The purpose of the study was to compare presbyopia progression in subjects with short and normal tear breakup time and to explore the severity of common ocular symptoms associated with presbyopia progression.

Method

We conducted a clinic-based, retrospective, cross-sectional study. Inclusion criteria were bilateral phakic patients aged 40–69 years with best-corrected distance visual acuity better than 20/30, and exclusion criteria were the use of glaucoma eye drops, any disease affecting vision, or history of ocular surgery. We measured the binocular near add power and compared the results using Kaplan-Meier analysis. Association between near add power and ocular symptoms was explored.

Results

There were 1411 participants (mean age of 50.1 years). There were no significant differences in age, intraocular pressure, spherical equivalent, astigmatism, or anisometropia between the sexes. Kaplan-Meier analysis indicated that women with short tear breakup time reached the endpoint (near add power of +3.00 D) significantly earlier than those with normal tear breakup time (P = 0.043; Cox-Mantel test). Eye fatigue was most severe in the group with an add power of 1.25-2.00 D. Near add power was correlated with hyperopia, astigmatic errors, and anisometropia.

Conclusions

This study suggests an exacerbation of presbyopia progression in women with short tear breakup time. Eye fatigue was most severe in those with an add power of 1.25-2.00 D.

OSDI Outcomes Based on Patient Demographic and Wear Patterns in Prosthetic Replacement of the Ocular Surface Ecosystem

PURPOSE

To evaluate the impact of prosthetic replacement of the ocular surface ecosystem (BostonSight PROSE) treatment on symptom outcomes based on the Ocular Surface Disease Index (OSDI).

PATIENTS AND METHODS

This was a single-center, retrospective analysis of consecutive patients who initiated PROSE treatment between September 2017 and December 2019 by the same clinician. The primary outcome measure was to compare OSDI survey scores at baseline prior to PROSE treatment and at follow-up, after PROSE treatment. Indication for treatment, sex, age, device diameter, average wear time, preexisting mental illness, duration of PROSE wear, and status of PROSE wear at follow-up were also studied.

RESULTS

A total of 134 patients underwent PROSE treatment and completed a baseline OSDI survey during the study period. Forty-three patients completed a follow-up OSDI survey and were included in the study analysis. The most common treatment indications were keratoconjunctivitis sicca (n=27) and corneal ectasia (n=16). Baseline average OSDI score was 56.9±23.7 for the 43 subjects who completed a subsequent OSDI survey. The last documented average follow-up OSDI for those 43 subjects was 23.8±15.6, median (IQR) of 22.9 (10.4 to 32.3), and a statistically significant 54.7±27.6% average improvement from baseline (p<0.01). All patients, except for two, showed improvement in OSDI score. Statistically significant improvement occurred regardless of underlying diagnosis with no statistically significant difference based on age, sex, mental illness, or device diameter and no statistical correlation with average wear time, or duration of PROSE wear.

CONCLUSION

PROSE treatment improves visual function and symptom relief as demonstrated by the OSDI survey. Sex, age, preexisting mental illness, device diameter, average wear time, and duration of wear had no statistically significant impact on OSDI outcomes.

Understanding risks of refractive error among Chinese children amidst pandemic disruptions: results from a rapid survey

BACKGROUND

Despite effectiveness in delaying the spread of the pandemic, frequent and extended disruption to children's livelihoods have fomented new norms in which learning routines encounter immense change. In particular, increased sedentary e-learning engagement with electronic screens and exposure to stressful circumstances are likely to pose adverse risks for children's vision development.

METHODS

This present study examines the link between near-sighted refractive error, and sedentary exposure to electronic screens, psychosocial stress level, and outdoor activities. A Rapid Survey Methodology (RSM) design was utilized to collect information on subject's vision condition, sedentary electronic screen use, and level of psychosocial stress, in addition to detailed socio-demographic background characteristics.

RESULTS

This study involves 2234 subjects enrolled in 1st to 6th grade in primary schools. Every 1 diopter hour increase in electronic screen use per day is associated with 1.036 OR (95% CI =1.024-1.047, p-value< 0.050), while every 1 h • W m^- 2 sr^- 1 of illuminance-weighted electronic screen use per day is associated with 2.285 OR (95% CI =1.829-2.855, p-value< 0.050) increased likelihood of near-sighted refractive error. Higher level of psychosocial stress is associated with 2.441 OR (95% CI =1.870-3.187, p-value< 0.050) and 2.403 OR (95% CI =1.839-3.141, p-value< 0.050) increased likelihood of near-sighted refractive error. Frequency of outdoor activity is not significantly associated with increased likelihood of near-sighted refractive error (p-value> 0.050).

CONCLUSIONS

Findings in this study show that many factors, including grade level and prior vision condition, contribute to increased risks of near-sighted refractive error during the COVID-19 pandemic. More strikingly, pandemic-related behavioral modifications such as lengthy sedentary electronic screen use and elevated levels of psychosocial stress are two critical channels affecting children's eye health.

Role of Immune Cell Diversity and Heterogeneity in Corneal Graft Survival: A Systematic Review and Meta-Analysis

Corneal transplantation is one of the most successful forms of solid organ transplantation; however, immune rejection is still a major cause of corneal graft failure. Both innate and adaptive immunity play a significant role in allograft tolerance. Therefore, immune cells, cytokines, and signal-transduction pathways are critical therapeutic targets. In this analysis, we aimed to review the current literature on various immunotherapeutic approaches for corneal-allograft rejection using the PubMed, EMBASE, Web of Science, Cochrane, and China National Knowledge Infrastructure. Retrievable data for meta-analysis were screened and assessed. The review, which evaluated multiple immunotherapeutic approaches to prevent corneal allograft rejection, showed extensive involvement of innate and adaptive immunity components. Understanding the contribution of this immune diversity to the ocular surface is critical for ensuring corneal allograft survival.

Assessment of a Cationic Emulsion to Control the Tear Film Evaporation Rate

PURPOSE

To investigate the effect of a single application of cationic emulsion in controlling tear film evaporation and improving tear quality and quantity.

MATERIALS A METHODS

Twenty male subjects diagnosed with DE were enrolled in the study with an average age of 45.8 ± 6.37 years. The tear film parameters were observed at several time points post-instillation of the cationic emulsion (10, 20, 30, and 60 min). The tear evaporation rate (TER) was measured with a VapoMeter. Noninvasive tear break-up time and meniscus height were assessed using OCULUS Keratograph.

RESULTS

TER decreased by more than 20% at 20, 30, and 60 minutes time points after instillation of single drop of cationic emulsion. Also, a significant improvement in tear film stability was found at all time points following the instillation of cationic emulsion eye drops. The mean tear break-up time increased from 5.55 ± 2.87 to 6.6 ± 4.2 sec at 60 minutes. The maximum increase in tear break-up time occurred at 30 minutes time point. The TMH was also significantly higher post-instillation of oil emulsion eye drops. There was a significant increase in the TMH post-therapy with oil drop at all time points.

CONCLUSION

The overall study findings of this study illustrate that the single application of a cationic emulsion effectively controls tear film evaporation in patients with mild to moderate DEs. The cationic emulsion efficiently enhanced both the tear film stability and the tear meniscus volume.

Changes in Corneal Epithelial Thickness Induced by Topical Antiglaucoma Medications

Corneal thickness measurement is important for assessing intraocular pressure in patients with glaucoma. This study investigated the changes in corneal epithelial thickness (CET) induced by antiglaucoma medications and explored the factors affecting CET measurement. CET was measured over a 9.0 mm diameter area by using Fourier domain optical coherence tomography in 125 patients with primary open-angle glaucoma and 125 age-matched controls without glaucoma. The influence of sex, age, benzalkonium chloride (BAK)-containing instillations, disease severity, and types and numbers of medications was analyzed using simple and multiple regression analyses. CET over 25 sectors was smaller in the glaucoma group than in the control group (mean difference of 4.2 µm in the central 2.0 mm zone; 52.8 ± 3.6 vs. 48.5 ± 3.9, p < 0.001). Simple regression analysis revealed age, use of β-blockers, prostaglandin, carbonic anhydrase inhibitors, total number of medications, and number of daily BAK-containing instillations were associated with a thinner epithelium. Multiple regression analysis revealed β-blockers, prostaglandin, and number of BAK-containing instillations were significant factors. Use of β-blockers and number of BAK-containing instillations were also associated with a thinner epithelium in the monotherapy subgroup analysis. CET was significantly smaller in patients with glaucoma receiving topical medications and was affected by the use of β-blockers, prostaglandin, and BAK.

Simulations of Decentration and Tilt of a Supplementary Sulcus-Fixated Intraocular Lens in a Polypseudophakic Combination Using Ray-Tracing Software

This study aimed to assess image quality after the tilt and decentration of supplementary intraocular lenses (IOLs) in a two-lens configuration. One was designed for sulcus fixation with a nominal power range of 1D–10D and was combined with a capsular fixation 20D IOL. The optical performance of a ray-tracing model was tested under IOL misalignment through the area under the modulation transfer function (MTFa) and wave aberrations. Tilting by 10° resulted in a 4% reduction of the MTFa for a 10D IOL as compared to 9% for the 20D lens. The two models demonstrated good tolerance to a 1 mm decentration; as for the 10D sulcus-fixated lens, the MTFa loss was 2%, and 4% for the capsular fixation lens. Coma and astigmatism increased three- and four-fold, respectively, after a 10° tilt compared to the aberration level induced by the 1 mm decentration. Both analyses showed a trend towards a lower MTF impact and fewer optical errors with decreasing nominal power. In conclusion, when misaligned, low-power sulcus-fixated IOLs might retain their good optical quality. An extreme tilt of 10° has a more detrimental effect on the IOL performance than a 1 mm decentration. The proper alignment of a high-power capsular fixation lens is important in achieving a desirable postoperative outcome.

How to Predict the Suitability for Corneal Donorship?

Background: In Germany, more than one-third of donor corneas harvested are not suitable for transplantation. We evaluated the factors associated with the usability of donor corneas. Method: Data from 2032 consecutive donor corneas harvested at the Rhineland-Palatinate Eye Bank in Mainz, Germany, were retrospectively analyzed. Factors of interest were age, sex, lens status, cause of death, cardiopulmonary resuscitation (CPR), death-to-explantation-interval (DEI), and the influence of these factors on the proportion of discarded donor corneas. Factors associated with endothelial cell density (ECD) were analyzed in a linear regression mixed model. Results: Higher donor age, male gender, pseudophakic lens status, and longer DEI were associated with significantly reduced ECD. With respect to DEI, the estimated cell loss was 7 ± 2 cells/mm²/hour (p < 0.001). Age was associated with a lower ECD of 6 ± 2 cells/mm² per year (p = 0.001). Female ECD was 189 ± 44 cells/mm² higher than male ECD (p < 0.001). Pseudophakic eyes had 378 ± 42 cells/mm² less compared with phakic eyes (p < 0.001). Cause of death did not affect the ECD. Of note, 55% and 38% of corneas harvested on the second and third postmortem day, respectively, and 45% of corneas from donors older than 80 years were still suitable for transplantation. Conclusions: In the context of a growing need for donor corneas, we do not recommend limiting donor age and collection time to 24 h or excluding oncology donors, as is the practice in many countries. Therefore, we propose a mathematical model for better donor preselection.

Ocular Manifestations of Post-Acute COVID-19 Syndrome, Upper Egypt Early Report

Purpose

To evaluate the ocular manifestations of post-acute COVID-19 syndrome.

Methods

A retrospective, comparative study included 100 patients who had recovered from COVID-19 and 100 controls who were recruited by stratified randomization from hospital registration system and analyzed regarding history, full ophthalmological examination, general examination including internal medicine and neurological evaluation. Laboratory tests were done.

Results

Mean±SD of age were 55.5 ± 6.2 in COVID group vs 56.5 ± 5.8 in control group; P value = 0.7. In COVID group, 57 patients (57%) were males vs 51 patients (51%) in control group (P value = 0.39), the other compared parameters including history and risk factors showed non-significant difference except for ESR and D-dimer which were elevated in COVID group. In COVID group, 5 patients (5%) were having retinal vascular occlusion, 2 patients (2%) were having anterior ischemic optic neuropathy AION, 3 patients (3%) were having uveitis and 2 patients (2%) were having central serous chorioretinopathy CSCR. While in control group, 2 patients (2%) were having retinal vascular occlusion, and none had AION, uveitis or CSCR (P value = 0.006).

Conclusion

Post-acute COVID-19 syndrome could affect the eyes in the form of coagulation problems, neurological morbidities, and other manifestations. This necessitates meticulous follow-up of recovered patients from COVID-19.

Visual Acuity and Number of Amniotic Membrane Layers as Indicators of Efficacy in Amniotic Membrane Transplantation for Corneal Ulcers: A Multicenter Study

BACKGROUND

To evaluate new indicators in the efficacy of amniotic membrane transplantation (AMT) for non-healing corneal ulcers (NHCUs).

METHODS

Retrospective, multicenter study. In total, 223 AMTs for NHCU in 191 patients were assessed. The main outcomes studied were the success rate of AMT (complete re-epithelization), postoperative visual acuity (VA) gain, and number of AM layers transplanted.

RESULTS

The overall AMT success rate was 74.4%. In 92% of our patients VA stability or improvement. Postoperative VA was significantly higher than preoperative VA in the entire cohort (p < 0.001) and in all etiological groups of ulcers (post-bacterial, p ≤ 0.001; post-herpetic, p ≤ 0.0038; neurotrophic ulcers, p ≤ 0.014; non-rheumatic peripheral, p ≤ 0.001; and ulcers secondary to lagophthalmos and eyelid malposition or trauma, p ≤ 0.004). Most participants (56.5%) presented a preoperative VA equal to or less than counting fingers (≤0.01). Of these, 13.5% reached a postoperative VA equal to or better than legal blindness (≥0.05) after AMT. A higher success rate was observed in the monolayer than in the multilayer AMT (79.5% and 64.9%, respectively; p = 0.018). No statistically significant values were found between the number of layers transplanted and VA gain (p = 0.509).

CONCLUSION

AMT is not only beneficial in achieving complete re-epithelialization in NHCUs but also in improving postoperative VA; these improvements are independent of etiologies of ulcers. Furthermore, the use of monolayer AMT seems to be a more appropriate option than multilayer AMT for NHCU since the multilayer AMT did not present better outcomes (success rate and VA gain) compared to monolayer AMT in the different types of ulcers studied.

Metagenomic Shotgun Sequencing Analysis of Canalicular Concretions in Lacrimal Canaliculitis Cases

Lacrimal canaliculitis is a rare infection of the lacrimal canaliculi with canalicular concretions formed by aggregation of organisms. Metagenomic shotgun sequencing analysis using next-generation sequencing has been used to detect pathogens directly from clinical samples. Using this technology, we report cases of successful pathogen detection of canalicular concretions in lacrimal canaliculitis cases. We investigated patients with primary lacrimal canaliculitis examined in the eye clinics of four hospitals from February 2015 to July 2017. Eighteen canalicular concretion specimens collected from 18 eyes of 17 patients were analyzed by shotgun metagenomics sequencing using the MiSeq platform (Illumina). Taxonomic classification was performed using the GenBank NT database. The canalicular concretion diversity was characterized using the Shannon diversity index. This study included 18 eyes (17 patients, 77.1 ± 6.1 years): 82.4% were women with lacrimal canaliculitis; canalicular concretions were obtained from 12 eyes using lacrimal endoscopy and six eyes using canaliculotomy with curettage. Sequencing analysis detected bacteria in all samples (Shannon diversity index, 0.05–1.47). The following genera of anaerobic bacteria (>1% abundance) were identified: Actinomyces spp. in 15 eyes, Propionibacterium spp., Parvimonas spp. in 11 eyes, Prevotella spp. in 9 eyes, Fusobacterium spp. in 6 eyes, Selenomonas spp. in 5 eyes, Aggregatibacter spp. in 3 eyes, facultative and aerobic bacteria such as Streptococcus spp. in 13 eyes, Campylobacter spp. in 6 eyes, and Haemophilus spp. in 3 eyes. The most common combinations were Actinomyces spp. and Streptococcus spp. and Parvinomonas spp. and Streptococcus spp., found in 10 cases. Pathogens were identified successfully using metagenomic shotgun sequencing analysis in patients with canalicular concretions. Canalicular concretions are polymicrobial with anaerobic and facultative, aerobic bacteria.

High-Resolution Optical Coherence Tomography Angiography Characteristics of Limbal Stem Cell Deficiency

This study aimed to identify the anterior segment high-resolution optical coherence tomography (HR-OCT) and HR-OCT angiography (HR-OCTA) features suggestive of limbal stem cell deficiency (LSCD) as confirmed by both impression cytology (IC) and in vivo confocal microscopy (IVCM). This was a single-centre prospective cross-sectional study including 24 eyes of 22 patients with clinical suspicion of LSCD based on peripheral superficial corneal vascularisation and scarring. On IC and IVCM, performed and interpreted by blinded observers, 12 eyes each were diagnosed with and without LSCD. Additionally, 10 eyes of 5 healthy volunteers with no ocular pathology were also imaged. The 136 HR-OCT/A images of these 34 eyes were analysed with respect to 12 imaging parameters; the parameters most suggestive of LSCD were identified and the sensitivity and specificity were calculated. In the LSCD group, the most common aetiology was ocular chemical burns (83%), whereas in the non-LSCD group, the most common aetiology was viral keratitis (67%). Multiple logistic regression analysis revealed that mean epithelial reflectivity, mean stromal reflectivity, and mean superficial vascular density were the parameters that were diagnostic of LSCD on HR-OCT/A (p < 0.0001). A ratio of the mean epithelial reflectivity to stromal reflectivity of >1.29 corresponded with a high sensitivity (91.7%) and specificity (98.75%); while a mean superficial vascular density score of >0.38 corresponded with a sensitivity of 97.9% and specificity of 73.8%. In conclusion, HR-OCT/A as a non-invasive imaging modality could prove to be a useful tool for confirming the diagnosis of LSCD, with potential clinical and research applications.

Intraocular Foreign Body: Diagnostic Protocols and Treatment Strategies in Ocular Trauma Patients

Intraocular foreign bodies (IOFBs) are critical ophthalmic emergencies that require urgent diagnosis and treatment to prevent blindness or globe loss. This study aimed to examine the various clinical presentations of IOFBs, determine the prognostic factors for final visual outcomes, establish diagnostic protocols, and update treatment strategies for patients with IOFBs. We retrospectively reviewed patients with IOFBs between 2005 and 2019. The mean age of the patients was 46.7 years, and the most common mechanism of injury was hammering (32.7%). The most common location of IOFBs was the retina and choroid (57.7%), and the IOFBs were mainly metal (76.9%). Multivariate regression analysis showed that poor final visual outcomes (<20/200) were associated with posterior segment IOFBs (odds ratio (OR) = 11.556, p = 0.033) and retinal detachment (OR = 4.781, p = 0.034). Diagnosing a retained IOFB is essential for establishing the management of patients with ocular trauma. To identify IOFBs, ocular imaging modalities, including computed tomography or ultrasonography, should be considered. Different strategies should be employed during the surgical removal of IOFBs depending on the material, location, and size of the IOFB.

The "Quarantine Dry Eye": The Lockdown for Coronavirus Disease 2019 and Its Implications for Ocular Surface Health

The pandemic of coronavirus disease 2019 (COVID-19) has led many countries of the world to impose a series of containment measures such as lockdowns (mass quarantines), curfews or similar restrictions (eg, stay-at-home orders, or shelter-in-place orders). All these restrictions were established in order to limit spread of COVID-19. Thus, approximately 3.9 billion people worldwide were under lockdown by early April 2020. During this time (home confinement), some solutions have been proposed by experts to improve work and school productivity, including smart working and online school lessons. However, many of the restrictive measures are likely to act as predisposing factors for dry eye disease (DED), directly or related to sick building syndrome (SBS). Herein, we discuss the implications of quarantine measures on eye health, in particular on DED associated with SBS, and introduce some potential preventive strategies for lockdown-related ocular surface disorders. Several risk factors are implicated in their pathogenesis, including environmental changes (eg, air quality) and modifications in personal behaviors (eg, the abuse of digital devices, malnutrition, and sleep/psychiatric disorders). Considering a number of predisposing factors for DED, it is possible to state that patients under lockdown are at risk of ocular surface alterations. Accordingly, the COVID-19 pandemic era is expected to determine an increase in dry eye patients all around the world (a new phenomenon that we propose to name the "quarantine dry eye") in the event that the restrictive measures will be recursively extended over time.

Zygomatic implant penetration to the central portion of orbit: a case report

Background

Zygomatic implants have been proposed in literature for atrophic maxillary fixed oral rehabilitations. The aim of the present research was to evaluate, by a clinical and tomography assessment, a surgical complication of a zygomatic implant penetration to the orbit.

Case presentation

A 56 year-old female patient was visited for pain and swelling in the left orbit after a zygomatic implant protocol. The orbit invasion of the zygomatic implant screw was confirmed by the CBCT scan. The patient was treated for surgical implant removal and the peri- and post-operative symptoms were assessed. No neurological complications were reported at the follow-up. The ocular motility and the visual acuity were well maintained. No purulent secretion or inflammatory evidence were reported in the post-operative healing phases.

Conclusion

The penetration of the orbit during a zygomatic implant positioning is a surgical complication that could compromise the sight and movements of the eye. In the present case report, a zygomatic implant removal resulted in an uneventful healing phase with recovery of the eye functions.

Evaluation of Eye-Pain Severity between Dry-Eye Subtypes

The aim of this study was to assess eye pain between dry eye (DE) subtypes using questionnaires and the PainVision^® (Osachi) apparatus. This study involved 52 eyes of 52 DE patients with eye pain (43 females and 9 males; mean age: 64.2 ± 13.2 (mean ± SD) years) who were classified into three DE subtypes (aqueous deficient DE (ADDE); decreased wettability DE (DWDE); and increased evaporation DE (IEDE)) based on fluorescein breakup pattern. In all subjects, severity of eye pain was evaluated using PainVision^®, the DE-symptom-questionnaire visual analog scale (DSQ-VAS), and the Short-Form McGill Pain Questionnaire 2 (SF-MPQ-2). The severity of eye pain was compared between the three DE subtypes. PainVision^® findings revealed greater severity of eye pain in ADDE and DWDE than in IEDE (p < 0.05, respectively), despite no difference being found in each questionnaire. A significant correlation was found between eye pain in DSQ-VAS and continuous pain, intermittent pain, neuropathic pain, and total pain in SF-MPQ-2 (R = 0.50, 0.49, 0.47, and 0.56, respectively) (all: p < 0.001). Greater severity of eye pain was found in ADDE and DWDE than in IEDE, and PainVision^® was found useful for the objective assessment of eye pain.

Short-Term Reproducibility of MUC5AC Measurement in Human Tear Fluid

The assessment of tear fluid components is a common and valuable approach to understanding ocular surface disease and testing the efficacy of novel therapeutic strategies. However, the interpretation and utility of the findings can be limited by changes in the composition of the tear film, particularly in studies requiring repetitive patient sampling. Here, tear samples were collected twice within a one-hour interval to evaluate the short-term reproducibility of an immunoassay aimed to measure the amount of MUC5AC mucin. We found no statistical difference in total protein or MUC5AC content between the two consecutive collections of tear fluid, although the inter-individual variability in each group was high, with coefficients of variation exceeding 30% and 50%, respectively. Scatterplots showed a significant correlation in both protein and MUC5AC following collection within a one-hour interval. These data indicate that, regardless of the high inter-individual variability, repeated collection of tear fluid within an hour interval produces reproducible intra-individual data in terms of MUC5AC mucin content, and suggest that the normal mucin composition of the tear fluid can be re-established within an hour of the initial collection.

The Association between Tear Film Thickness as Measured with OCT and Symptoms and Signs of Dry Eye Disease: A Pooled Analysis of 6 Clinical Trials

Purpose: To determine the association between tear film thickness (TFT) as measured with ultra-high resolution optical coherence tomography (UHR-OCT) and signs and symptoms of dry eye disease (DED). Methods: A total of 450 eyes from 225 patients with DED from six different randomized clinical trials were included in this pooled analysis. In all subjects, TFT was measured with a custom-built UHR-OCT system. Symptoms of DED were quantified using a standardized Ocular Surface Disease Index (OSD)I questionnaire and clinical signs including tear film break up time (TFBUT) and Schirmer I test were assessed. Associations of the average TFT with OSDI, TFBUT, and Schirmer I test were calculated using a linear regression analysis. Results: The average TFT of the included sample (mean age, 45.0 ± 13.3 years; 65% female) was 4.2 ± 0.5 µm and the OSDI 36.2 ± 10.4. A significant negative correlation was found between TFT and OSDI (r = −0.36 to −0.31; p < 0.001). Tear break up time and Schirmer I test were not correlated with OSDI. Significant albeit weak correlations were found between TFT and TFBUT (r = 0.17 to 0.25; p < 0.01) as well as Schirmer I (r = 0.36 to 0.37; p < 0.001). Subgroup analysis revealed that the correlation was stronger in the subjects with abnormal Schirmer I (<15 mm; r = 0.50 to 0.54; p < 0.001). Conclusions: The present study demonstrates an objective measurement of TFT using a novel OCT approach for DED that correlates with symptoms and signs of DED. Our data are consistent with the idea that TFT represents the aqueous-deficient component of DED.

The architecture of corneal stromal striae on optical coherence tomography and histology in an animal model and in humans

The purpose of this study was to use a portable optical coherence tomography (OCT) for characterization of corneal stromal striae (CSS) in an ovine animal model and human corneas with histological correlation, in order to evaluate their architectural pattern by image analysis. Forty-six eyes from female adult sheep (older than 2 years), and 12 human corneas, were included in our study. The eyes were examined in situ by a portable OCT, without enucleation. All OCT scans were performed immediately after death, and then the eyes were delivered to a qualified histology laboratory. In the ovine animal model, CSS were detected with OCT in 89.1% (41/46) of individual scans and in 93.4% (43/46) of histological slices. In human corneas, CSS were found in 58.3% (7/12) of cases. In both corneal types, CSS appeared as "V"- or "X"-shaped structures, with very similar angle values of 70.8° ± 4° on OCT images and 71° ± 4° on histological slices (p ≤ 0.01). Data analysis demonstrated an excellent degree of reproducibility and inter-rater reliability of measurements (p < 0.001). The present study demonstrated that by using a portable OCT device, CSS can be visualized in ovine and human corneas. This finding suggests their generalized presence in various mammals. The frequent observation, close to 60%, of such collagen texture in the corneal stroma, similar to a 'truss bridge' design, permits to presume that it plays an important structural role, aimed to distribute tensile and compressive forces in various directions, conferring resilience properties to the cornea.

Fourier-Domain OCT Imaging of the Ocular Surface and Tear Film Dynamics: A Review of the State of the Art and an Integrative Model of the Tear Behavior During the Inter-Blink Period and Visual Fixation

In the last few decades, the ocular surface and the tear film have been noninvasively investigated in vivo, in a three-dimensional, high resolution, and real-time mode, by optical coherence tomography (OCT). Recently, OCT technology has made great strides in improving the acquisition speed and image resolution, thus increasing its impact in daily clinical practice and in the research setting. All these results have been achieved because of a transition from traditional time-domain (TD) to Fourier-domain (FD) technology. FD-OCT devices include a spectrometer in the receiver that analyzes the spectrum of reflected light on the retina or ocular surface and transforms it into information about the depth of the structures according to the Fourier principle. In this review, we summarize and provide the state-of-the-art in FD-OCT imaging of the ocular surface system, addressing specific aspects such as tear film dynamics and epithelial changes under physiologic and pathologic conditions. A theory on the dynamic nature of the tear film has been developed to explain the variations within the individual compartments. Moreover, an integrative model of tear film behavior during the inter-blink period and visual fixation is proposed.

A study of refractory cases of persistent epithelial defects associated with dry eye syndrome and recurrent corneal erosions successfully treated with cyclosporine A 0.05% eye drops

Background: Effective and tolerable therapeutic strategies for patients with refractory persistent epithelial defects (PEDs) are limited and generally provide poor outcomes. This retrospective case review describes four refractory cases of PEDs associated with recurrent corneal erosions (RCEs) and dry eye disease (DED), which were successfully treated with cyclosporine eye drops.

Methods: Patients were treated with cyclosporine A 0.05% eye drops twice a day for at least 12 months. At enrolling time, each patient was asked to suspend topical steroids or other eye drops used for ocular surface abnormalities with the exception of lubricants and eye washing. A complete evaluation of ocular surface symptoms was performed including the McMonnies Dry Eye Questionnaire, Ocular Surface Disease Index, slit-lamp biomicroscopy, fluorescein break-up time, the fluorescein staining of the cornea and conjunctiva (according to the Oxford grading system), the Schirmer I test, and the meibomian secretion after digital pressure application on the lids. This set of exams was carried out at baseline and repeated at all follow-up assessments.

Results: All participants that did not benefit from previous therapies, including corticosteroids tapering schedule, showed an important improvement in the clinical picture after two months with topical cyclosporine medication. Moreover, after 12 months of continuous therapy, all patients showed a clinical improvement in DED signs and symptoms, related to the absence of new RCE episodes. The treatment was well tolerated, and no adverse effects were reported.

Conclusion: Although a small number of cases were available of our analysis, the treatment with cyclosporine eye drops represents a promising approach in the management of refractory PEDs with associated ocular comorbidities, since it may reduce the RCE episodes and improve the tear film stability, in absence of systemic or local side effects.