Changes in the tear film and meibomian gland morphology between preclinical dry eye and normal subjects represented by ocular surface disease index scores.

Tear film and MG morphology play an essential role in detecting dry eyes and Meibomian Gland Dysfunction (MGD). Previous studies have reported these changes in cases diagnosed with dry eyes. However, it is important to study these changes among subjects with symptoms of dry eyes without signs. Hence, this study evaluated the changes in the tear film and meibomian gland (MG) morphology among subjects with pre-clinical dry eye and compared it with the normals defined by the Ocular Surface Disease Index score. One hundred and fifty subjects were enrolled in this prospective cross-sectional study. All the subjects completed the Ocular Surface Disease Index (OSDI) questionnaire and the Computer Vision Syndrome Questionnaire (CVS-Q). Tear film tests such as non-invasive break-up time (NIBUT), tear meniscus height (TMH), lipid layer pattern, Schirmer's test, and corneal staining were performed. Images were captured from both the upper and the lower eyelids to study the MG morphology. TMH, MG length, thickness, loss, and tortuosity were measured using ImageJ software. Subjects were differentiated into two groups based on an OSDI threshold score of ≥13 as preclinical dry eye and normals. Among all the subjects, 43.6% of them were categorized as pre-clinical dry eye, and 56.4% as normals. In the pre-clinical dry eye group, a significant reduction in NIBUT (Z = -2.13, p = 0.03) and MG length of the lower lid (Z = -2.58, p = 0.01) was found when compared to normals. TMH, Schirmer's test, and MG width did not vary among both groups (p > 0.05). Similarly, MG loss and tortuosity score was higher in the pre-clinical dry eye group, but did not show any statistical significance (p > 0.05). The majority of the young individuals presenting for the regular eye examination may have pre-clinical dry eye based on their OSDI scores. Hence, it is important to administer the OSDI questionnaire and perform non-invasive tests such as NIBUT and IR imaging of MG as a part of the routine eye examination.

Visual photosensitivity threshold and objective photosensitivity luminance in healthy human eyes assessed using an automated ocular photosensitivity analyser: a step towards translation of a clinical tool for assessing photophobia.

PURPOSE: To evaluate the visual photosensitivity threshold and objective photosensitivity luminance in healthy eyes, thereby providing a normative dataset that will lead to a better understanding of diseases causing photophobia. METHODS: This was a prospective cross-sectional study. Emmetropes whose visual acuity was better than 0.18 logMAR (6/9) with no other ocular abnormality were included. Headache Impact Test-6 and visual light sensitivity questionnaires were administered. Visual photosensitivity threshold was measured subjectively using the ocular photosensitivity analyser. Objective photosensitivity luminance was assessed manually by evaluating videos recorded using an infrared camera and noting the intensity of light at the first squeezing reflex. RESULTS: Seventy five normal subjects (age range, 7-71 years) were included. Median age was 32.7 years (inter-quartile range, 20.3-47.9 years). Forty (53.3%) were males. Median Headache Impact Test score was 38 (inter-quartile range, 36-42) and visual light sensitivity questionnaire score was 11 (inter-quartile range, 8-15). Mean (standard deviation) right eye, left eye and binocular visual photosensitivity threshold was 3.34 (0.78), 3.33 (0.81) and 3.37 (0.78) loglux, respectively. There was a significant negative correlation of visual light sensitivity questionnaire scores with right eye, left eye and binocular visual photosensitivity thresholds, and positive correlation of age with binocular visual photosensitivity thresholds. Mean (standard deviation) right eye, left eye and binocular objective photosensitivity luminance was 3.25 (0.55), 3.35 (0.47) and 3.15 (0.52) loglux, respectively. Age was only positively correlated with binocular objective photosensitivity luminance, and there was no correlation between age and right eye or left eye objective photosensitivity luminance. CONCLUSIONS: The study characterised, for the first time, objective photosensitivity luminance and established normative data for both visual photosensitivity threshold and objective photosensitivity luminance. The data will help in understanding the pathophysiology of diseases causing photophobia, monitoring the disease progression and evaluating treatment modalities.

Risk Factors for Contact Lens-Related Microbial Keratitis and Associated Vision Loss in a South Indian Population.

OBJECTIVES: To identify risk factors associated with contact lens-related microbial keratitis (CL-MK) and subsequent vision loss in a south Indian population. METHODS: A retrospective study of medical records at the LV Prasad Eye Institute in Hyderabad, India, of patients diagnosed with CL-MK and of controls who had no history of corneal inflammation during contact lens wear was undertaken. Variables such as demographic data, contact lens wear details, duration of the event, visual acuity, epithelial defect and infiltrate size, and microbiology of the cornea during the event were collected. Differences between cases and controls were analyzed using parametric and nonparametric tests. Logistic regression was used to calculate the odds ratio (OR) and associated 95% confidence intervals in univariate and multivariate analyses for cases vs. controls and for factors associated with vision loss. RESULTS: One hundred sixty-seven cases of CL-MK and 153 controls were included in the analyses. Risk factors associated with the greatest increased OR for CL-related MK were: being in professional employment vs. a student (OR=3.9), disposing lenses yearly versus monthly or biweekly (OR=2.2), and any overnight wear (OR=2.8). Risk factors associated with vision loss were: high myopia (OR=3.6), severe vs. mild severity (OR=16.0), and hypopyon (OR=4.3). CONCLUSIONS: Identification of these risk factors may help inform safe contact lens wear habits and management strategies.

Microbial analyses of contact lens-associated microbial keratitis.

PURPOSE: To investigate the utility of additional microbial analyses to detect the causative microorganism of microbial keratitis and to determine the strength of association between clinical variables. METHODS: This retrospective study included 125 eyes of 123 people presenting with presumed infectious keratitis associated with contact lens wear, and examined between January 2001 and November 2011. RESULTS: Sixty-three male and 60 female patients with a mean age of 24.14 ( ±6.7) and 26.7 (±10.0) years, respectively, were included in the study. Among the samples tested, 38 (40%) corneal cultures, 85 (92%) contact lens cultures, and 49 (80%) contact lens case cultures yielded positive results. In the samples for which all microbial investigations were performed and corneal culture was positive, cultures of contact lenses and corneas yielded the same microbes in 94% of cases, and for contact lens case and corneal cultures 77% of cases yielded the same microbes. Importantly, these were monocultures of the same microbe isolated from the cornea in the contact lens and lens case cultures. The odds of having a positive corneal culture was 37 times higher (p = 0.008) when patients presented to the clinic 2 weeks after the onset of symptoms. Pseudomonas aeruginosa was the predominant organism isolated, and most isolates were susceptible to commonly used antimicrobials. CONCLUSIONS: Contact lens culture might be an effective test to perform to detect and determine the causative microorganism when corneal cultures are unavailable or yield no microorganisms upon culture. A longer duration of symptoms before presenting to the clinic was significantly associated with obtaining a positive corneal culture.

Evaluation of the ocular surface in asymptomatic glaucoma patients on topical medications and following trabeculectomy - A cross-sectional study.

Purpose: This present prospective, cross-sectional study aims to comprehensively evaluate the ocular surface in asymptomatic patients with diffuse blebs after trabeculectomy versus chronic anti-glaucoma medication use and compare it with the age-matched normal population. Methods: Objective clinical evaluation was done by tear film break-up time (TBUT) and Schirmer's test (ST) in the three groups-trabeculectomy >6 months with a diffuse bleb (Wurzburg bleb classification score ≧10), chronic anti-glaucoma medication (AGM >6 months) group, and normal population. In all groups, tear film osmolarity was checked with the TearLab® device (TearLab Corp., CA, USA), and subjective evaluation was performed by administering Ocular Surface Disease Index (OSDI) questionnaire. Patients already on chronic lubricants or any other drug for the treatment of dry eyes (viz. steroids, cyclosporin) or having symptoms suggestive of an abnormal ocular surface, who had undergone refractive or intraocular surgery, and contact lens users were excluded. Results: In total, 104 subjects/eyes were recruited over 6 weeks. Thirty-six eyes recruited in the trab group were compared with 33 eyes studied in the AGM group, and both these groups were compared to 35 normal eyes. When compared to normals, TBUT and ST were significantly lower (P = 0.003 and 0.014) and osmolarity and OSDI were statistically significantly higher (P = 0.007 and 0.003) in the AGM group, whereas only TBUT was statistically significantly different (P = 0.009) when the trab group was compared to normals. Also, when the trab group was compared to the AGM group, ST was found to be higher (P = 0.003) and osmolarity was lower (P = 0.034). Conclusion: To conclude, ocular surface is affected even in asymptomatic patients on AGM but near normalcy is possible following trabeculectomy when blebs are diffuse.

Prevalence and Patterns of Refractive Errors in Children and Young Adults in an Urban Region in South India: the Hyderabad Eye Study.

PURPOSE: To determine the prevalence of refractive error (RE) and associated risk factors for myopic refractive errors in children and young adults from the urban region of Hyderabad, South India. METHODS: Four thousand sixty-five (4,065) participants aged 6-22 years were enrolled and examined in this cross-sectional study conducted from October 2013 to January 2015. Participants were enrolled from a random sample of schools and universities in regions representative of urban Hyderabad. RE was determined using cycloplegic autorefraction. The association of demographic factors such as age, gender, and socio-economic category (SEC) (low/mid/high) with myopia was explored with logistic regression with robust standard error. RESULTS: Of the total participants, 2,259 were children aged 6-15 years and 1,806 were adolescents and young adults aged 16-22 years. Overall prevalence of myopia, high myopia (≤ -5.00D and ≤ -6.00 D), hyperopia, emmetropia, and astigmatism was 29.8% (95% CI: 26.0% to 33.6%, n = 1,216), 2.9% (95% CI: 1.9% to 3.9%, n = 120), 1.1% (95%CI: 0.7% to 1.5%, n = 46), 14.7% (95% CI: 12.4% to 17.0%, n = 599), 46.9% (95% CI: 43.7% to 50.1%, n = 1913) and 8.6% (95% CI: 7.4% to 9.9%, n = 352) respectively. A strong correlation existed between age and prevalence of myopia (R2 = 0.88, p < .001) and high myopia (R2 = 0.71, p < .001). Children from schools of low SEC (34.7%) had higher prevalence of myopia compared to the mid SEC (16.8%) (p = .043). CONCLUSION: Myopia was the most prevalent refractive error and increased with age in this urban population. More myopia was observed in schools of low SEC.

Effect of Deposition and Protease Digestion on the Ex Vivo Activity of Antimicrobial Peptide-Coated Contact Lenses.

A clinical study of antimicrobial contact lenses containing the cationic peptide Mel4 was conducted. The few adverse events that occurred with this lens occurred on or after 13 nights of wear. The current study examined whether the Mel4 contact lenses lost activity during wear and the mechanism of this loss. Participants wore contact lenses for up to 13 nights. Lenses were tested for their ability to reduce the adhesion of Pseudomonas aeruginosa and Staphylococcus aureus. The amount of protein and lipid extracted from lenses was measured. The ability of trypsin to affect the antimicrobial activity of Mel4-coated contact lenses was measured. Mel4-coated contact lenses lost their antimicrobial activity at six nights of wear for both bacteria. The amount of lipids (13 ± 11 vs. 21 ± 14 µg/lens at 13 nights wear) and proteins (8 ± 4 vs. 10 ± 3 mg/lens at 13 nights of wear) extracted from lenses was not different between Mel4-coated and uncoated lenses, and was not different after three nights when antimicrobial activity was maintained and thirteen nights when they had lost activity (lipid: 25 ± 17 vs. 13 ± 11, p = 0.2; protein: 8 ± 1 vs. 8 ± 4 mg/lens, p = 0.4). Trypsin digestion eliminated the antimicrobial activity of Mel4-coated lenses. In summary, Mel4-coated contact lenses lost antibacterial activity at six nights of wear, and the most likely reason was proteolytic digestion of the peptide. Future studies will design and test proteolytically stable peptide mimics as coatings for contact lenses.

Association of Single-Nucleotide Polymorphisms in Interleukin Genes with Microbial Keratitis in a South Indian Population.

BACKGROUND: To examine the relationship between single-nucleotide polymorphisms (SNPs) in interleukin (IL) genes and keratitis and its clinical manifestations. METHODS: SNPs in IL1B, IL6, CXCL8, IL10, and IL12B were analysed. Differences in frequencies of alleles, genotypes and haplotypes between cases and controls as well as associations between SNPs and clinical variables were calculated by χ2 tests with odds ratios. RESULTS: The minor homologous genotype in IL1B rs16944 (p = 0.036; odds ratio (OR) = 2.063, 95% confidence interval (CI): 1.048-4.061) and CXCL8 rs4073 (p = 0.041; OR = 0.463, 95% CI: 0.224-0.956) and the heterologous genotypes in IL6 rs1800795 (p = 0.046; OR = 0.563, 95% CI: 0.326-0.972) and IL12B rs2569254 (p = 0.0446; OR = 0.557, 95% CI: 0.314-0.989) or rs730691 (p = 0.0051; OR = 0.451, 95% CI: 0.260-0.784) were associated with keratitis. The minor genotype of rs16944 was associated with severe infection (p = 0.046). The heterologous genotype in rs2569254 was associated with hospital admission, photophobia, and mode of contact lens wear (p ≤ 0.041). The heterologous genotype in rs730691 was associated with blurred vision, discharge, anterior chamber reaction, and mode of wear (p ≤ 0.047). CONCLUSIONS: This study demonstrates that SNPs in IL1B and CXCL8 are associated with risk of developing keratitis. The study also found relationships between SNPs and clinical measures of keratitis. The potential for ethnic differences in frequency of SNPs and their association with keratitis should be followed up using different populations.

Ocular microbiota and lens contamination following Mel4 peptide-coated antimicrobial contact lens (MACL) extended wear.

PURPOSE: The purpose of this study was to investigate the effect of Mel4 antimicrobial peptide-coated contact lenses (MACL) on the microbiota of the conjunctiva and lenses during three months of extended wear. METHODS: One hundred and seventy-six participants were recruited into a randomised, contralateral, double masked, biweekly extended wear MACL and uncoated control lens trial. At the one month and 3-month visit, the conjunctival microbiota was sampled using sterile cotton swabs and contact lenses were collected aseptically. Standard microbiological procedures were employed for culture of the swabs and contact lenses and identification of the isolated microorganisms. RESULTS: Gram-positive bacteria (predominantly coagulase-negative staphylococci) were the most frequently isolated microbes from both contact lenses and conjunctiva. There was no difference in the frequency of isolation of most bacteria or fungi from the conjunctival swabs of eyes wearing either MACL or control lenses. The only exception was a higher frequency of eyes harbouring Staphylococcus arlettae when wearing control lenses (5%) versus MACL (<1%) (p = 0.002). There was no significant difference in the frequency of microbes isolated from MACL or control contact lenses. There were also no differences between lens types in the frequency of isolation of >1 microbial type per sampling occasion for either conjunctiva swabs or contact lenses. CONCLUSION: MACL wear did not change the conjunctival microbiota during extended wear, and the types of microbes isolated from MACL were similar to those isolated from control lenses.

Biocompatibility and Comfort during Extended Wear of Mel4 Peptide-Coated Antimicrobial Contact Lenses.

(1) Purpose: This study aimed to investigate the effects of Mel4 antimicrobial contact lenses (MACL) on the ocular surface and comfort during extended wear. (2) Methods: A prospective, randomised, double-masked, contralateral clinical trial was conducted with 176 subjects to evaluate the biocompatibility of contralateral wear of MACL. The wearing modality was 14-day extended lens wear for three months. The participants were assessed at lens dispensing, after one night, two weeks, one month and three months of extended wear and one month after study completion. (3) Results: There were no significant differences (p > 0.05) in ocular redness or palpebral roughness between Mel4 and control eyes at any of the study visits. There was no significant difference (p > 0.05) in corneal staining between Mel4 and control eyes. There were no significant differences in front surface wettability or deposits or back surface debris (p > 0.05). No statistically significant differences (p > 0.05) were found in comfort, dryness, CLDEQ-8 scores lens or edge awareness. There was no evidence for delayed reactions on the ocular surface after cessation of lens wear. (4) Conclusion: The novel MACLs showed similar comfort to control lenses and were biocompatible during extended wear. Thus, these lenses were compatible with the ocular surface.

Toll-like receptor gene polymorphisms in patients with keratitis.

OBJECTIVE: To investigate differences in SNPs in TLR genes between people who had keratitis and controls in an Indian population. METHODS: 145 cases of keratitis and 189 matched controls were recruited. DNA was extracted from peripheral blood. Single nucleotide polymorphisms (SNP) in TLR2 (n = 6), TLR4 (n = 15), TLR5 (n = 13) and TLR9 (n = 10) were analysed. The risk of developing keratitis was assessed based on allele, genotype and haplotype associations. RESULTS: For all cases of keratitis, the TLR4 SNP rs4986791 TC genotype frequency was significantly higher in cases (p = 0.006, OR = 1.96, 95 % CI 1.19-3.2). Including cases of only microbial keratitis (MK) revealed that genotypes in TLR2 SNP rs5743706 TA (p = 0.0001; OR = 8.61; 95 % CI 2.59-28.56)), TLR4 SNP s4986791 TC (p = 0.002; OR = 2.65; 95 % CI 1.39-5.07) were significantly more common for MK, whereas the TLR5 SNP rs2241096 A allele (p = 0.00316, OR = 0.42, 95 % CI 0.2-0.9286) and GA genotype (p = 0.016; OR = 0.45; 95 % CI 0.23-0.86) was significantly less common in MK cases. The TLR2 SNP rs5743706 genotype TA was significantly less common in the sterile keratitis (SK) group (p = 0.004, OR = 0.43, 95 %CI 0.24-0.77). Haplotype analysis of MK compared to controls showed that TLR2 AT was more common in controls (p = 0.003); TLR4 ACAC was more common in cases (p = 0.004); TLR5 TGGCA was more common in controls (p = 0.001). CONCLUSION: The present study revealed multiple associations between variants across TLR genes, which may have implications for understanding the underlying host factors, risk of developing keratitis and molecular pathogenesis in keratitis.

Effect of Antimicrobial Contact Lenses on Corneal Infiltrative Events: A Randomized Clinical Trial.

Purpose: To determine whether Mel4-coated antimicrobial contact lenses (MACLs) can reduce the incidence of corneal infiltrative events (CIEs) during extended wear. Methods: A prospective, randomized, double-masked, single-center, contralateral, extended contact lens wear clinical trial was conducted with 176 subjects. Each participant was randomly assigned to wear a MACL in one eye and an uncoated control contact lens in the contralateral eye or an extended-wear biweekly disposable modality for 3 months. The main outcome measures were the incidence of CIEs per 100 eye-months, identification of the microbial types colonizing the contact lenses or eyes at the time of the CIEs, and their susceptibility to Mel4. Results: Nine participants (5.1%) experienced unilateral CIEs; six participants had contact lens acute red eye, and three participants had infiltrative keratitis. The incidence rate for CIEs (0.4 events per 100 participant months; 1.7%) in the Mel4-coated lenses (test) was 69% less than that of the control lenses (1.3 events per 100 participant months; 3.4%; P = 0.29). All Gram-negative bacteria isolated from lenses and lids of participants with CIEs (Citrobacter diversus, Acinetobacter haemolyticus, and Acinetobacter lwoffii) were susceptible to Mel4 peptide; minimum inhibitory concentrations ranged from 15.6 to 62.5 µg/mL. Reduction of adhesion of these bacteria by Mel4-coated lenses ranged from 2.1 to 2.2 log10 colony-forming units/lens. Conclusions: MACLs had the capacity to reduce CIEs by at least 50% compared with uncoated control lenses during extended wear over 3 months; however, due to the relatively low rates of CIEs, the reduction was not statistically different compared with control lenses. Translational Relevance: This study provides evidence that antimicrobial contact lenses have the potential to reduce the incidence of corneal infiltrative events during extended wear.

COVID-19 guidelines for optometry and optical services post-lockdown.

The COVID-19 pandemic has caused disruption in everyone's lives globally. Optometrists, being primary health care professionals are at a higher risk of infection in their practices during these testing times. Optometrists and optical store owners need practically implementable guidelines as lockdown gets lifted in various parts of our country. As these practices gear up to provide eye examination and vision correction to people, they need to take necessary precautions to avoid any cross contaminations. Optometry Council of India guidelines were circulated among optometry and optical associations and among experts in various optometry specialty. A consensus among various bodies were arrived. These guidelines provide recommendation for optical and optometry practices.