Genetic diversity and persistent colonization of <Emphasis Type="Italic">Enterococcus faecalis</Emphasis> on ocular surfaces

Purpose

Enterococcus faecalis causes severe acute endophthalmitis and often leads to poor visual outcomes. Conjunctival bacterial cultures occasionally grow atypical bacteria including E. faecalis, which can potentially contribute to the development of postoperative endophthalmitis. However, the characteristics of these ocular E. faecalis strains are unknown. This study is the first attempt to determine the population characteristics of E. faecalis clinical isolates from eye infections and ocular commensals.

Study design

Retrospective

Methods

Twenty-eight E. faecalis ocular isolates were collected from 23 patients at 3 referring hospitals. The multilocus sequence typing (MLST) data were analyzed using the eBURST program. Phenotypes of cytolysin and gelatinase, antibiotic susceptibility, and mutations of the quinolone resistance-determining regions (QRDRs) of gyrA and parC were also examined. Pulsed-field gel electrophoresis (PFGE) was performed for strains from the same patients.

Results

PFGE revealed that 3 patients retained identical strains for 10 months to 2 and a half years. MLST identified 12 sequence types (STs), which were clustered into 3 clonal complexes (CCs) and 8 singletons, with ST179 the largest. Thirteen of the 23 isolates (56.5%) belonged to CC58, CC8, or CC2, which have previously been reported to be major CCs. Six of the 23 strains (26.0%) exhibited high-level quinolone resistance derived from mutations of the QRDRs in both gyrA and parC.

Conclusions

The sequence types of E. faecalis ocular isolates were divergent, with no eye-specific lineages observed. Persistent colonization of E. faecalis on the ocular surface was demonstrated in patients with chronic ocular surface diseases.

     

<Emphasis Type="Italic">MTHFR</Emphasis> and <Emphasis Type="Italic">MTHFD1</Emphasis> gene polymorphisms are not associated with pseudoexfoliation syndrome in South Indian population

Purpose

Pseudoexfoliation syndrome (PEX) is a late onset disorder of extracellular matrix turnover, associated systemically with cardiovascular and cerebrovascular disease. To evaluate the suggested association of polymorphisms of homocysteine metabolism genes MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) with PEX.

Methods

A case–control association study was undertaken, comprising a total of 1472 individuals including 860 unrelated PEX cases and 612 ethnic-matched cataract controls (CC). All the study subjects were genotyped for three SNPs using the TaqMan allelic discrimination assay. Association and statistical analysis were performed with PLINK 1.07 and STATA 11.1.

Results

Among the three SNPs genotyped, MTHFR polymorphisms did not exhibit significant association with PEX (rs1801131; p = 0.549, rs1801133; p = 0.408). The intronic SNP rs8006686 showed nearly significant association (p = 0.069), and however did not remain significant after Bonferroni correction.

Conclusion

Our study suggests no significant genetic association of MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) polymorphisms in South Indian PEX patients.

     

Occurrence of <Emphasis Type="Italic">Demodex</Emphasis> species in patients with blepharitis and in healthy individuals: a 10-year observational study

Purpose

Two Demodex species (eyelash mites)—D. folliculorum and D brevis—are believed to be associated with human skin and eye diseases. However, the clinical significance of infection with Demodex species remains controversial.

Study design

The aim of this study was to estimate the prevalence of ocular demodicosis in patients with blepharitis as compared with the prevalence in the healthy population in Poland.

Methods

This case-control prospective study was carried out from 2007 to 2016. The enrolled patients (668) were divided into 2 groups: the study group, comprising 553 patients with blepharitis (349 women and 204 men, aged 17–88 years), and the control group, comprising 115 healthy volunteers without a history of ocular pathologies (78 women and 37 men, aged 17–88 years). A sample of 10 eyelashes was taken aseptically from each eye of the examined person and later studied under a light microscope.

Results

Demodex species were found in 62.4% (345/544) of the patients in the study group and in 24.3% (28/100) of the controls (P = .001, OR = 0.006). The overall prevalence was 55.8% (373/668) in all the examined participants. The presence of Demodex infection increased with age in both groups. No association of Demodex infection with gender was found (119/204 vs 226/349; P > .05, OR 1.086). A high mean number of mites was present more frequently in patients aged older than 50 years and in those who complained especially about itching (P < .05).

Conclusion

The prevalence of ocular demodicosis is significantly correlated with blepharitis and increases with age.

     

The association of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> with choroidal and retinal nerve fiber layer thickness

Purpose

To investigate the effect of Helicobacter pylori (H. pylori) infection on choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT).

Methods

The study included 25 patients with H. pylori infection and 25 healthy individuals as the control group. Helicobacter pylori patients were classified as the pre-treatment (Group 1; n: 25) and the post-treatment (Group 2; n: 25). RNFLT and CT were measured before and after treatment of H. pylori infection, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (Spectralis, Heidelberg Engineering, Heidelberg, Germany). The axial length and intraocular pressure were also measured.

Results

The mean subfoveal CT was 320.96 ± 29.15 μm in Group 1 and 287.48 ± 49.17 in the control group (p = 0.007), while the mean subfoveal CT did not show any difference between Group 2 and the control group (p > 0.05). No statistically significant difference was determined between the H. pylori patients and the control group in respect of RNFLT values (p > 0.05).

Conclusions

CT increases during H. pylori infection and returns to the normal range within 6 weeks of treatment. RNFLT does not show any change during H. pylori infection. The data related to the subfoveal CT may be useful in understanding the pathogenesis of central serous chorioretinopathy developing in H. pylori patients.

     

Visual consequences of electronic reader use: a pilot study

Background

With the increasing prevalence of electronic readers (e-readers) for vocational and professional uses, it is important to discover if there are visual consequences in the use of these products. There are no studies in the literature quantifying the incidence or severity of eyestrain, nor are there clinical characteristics that may predispose to these symptoms with e-reader use.

Purpose

The primary objective of this pilot study was to assess the degree of eyestrain associated with e-reader use compared to traditional paper format. The secondary outcomes of this study were to assess the rate of eyestrain associated with e-reader use and identify any clinical characteristics that may be associated with the development of eyestrain.

Methods

Forty-four students were randomly assigned to study (e-reader iPAD) and control (print) groups. Participant posture, luminosity of the room, and reading distance from reading device were measured during a 1-h session for both groups. At the end of the session, questionnaires were administered to determine symptoms.

Results

Significantly higher rates of eyestrain (p = 0.008) and irritation (p = 0.011) were found among the iPAD study group as compared to the print ‘control’ group. The study group was also 4.9 times more likely to report severe eyestrain (95 % CI [1.4, 16.9]). No clinical characteristics predisposing to eyestrain could be identified.

Conclusions

These findings conclude that reading on e-readers may induce increased levels of irritation and eyestrain. Predisposing factors, etiology, and potential remedial interventions remain to be determined.

     

Association between the <Emphasis Type="Italic">8</Emphasis>-<Emphasis Type="Italic">oxoguanine DNA glycosylase</Emphasis> gene Ser326Cys polymorphism and age-related cataract: a systematic review and meta-analysis

Purpose

To investigate the association between the 8-oxoguanine DNA glycosylase (OGG1) gene Ser326Cys (rs1052133) polymorphism and age-related cataract (ARC).

Methods

MEDLINE and EMBASE were searched to identify potential studies published before May 19, 2017, investigating the association between the OGG1 gene Ser326Cys polymorphism and ARC risk. The quality of eligible studies was assessed using the Newcastle–Ottawa Scale tool. The association between the OGG1 gene Ser326Cys polymorphism and ARC was analyzed using meta-analysis. Publication bias and sensitivity analyses were also performed.

Results

Six studies were included in this systematic review, and five of these studies with Hardy–Weinberg equilibrium were included in a meta-analysis. The sample size of the meta-analysis was 3716, including 1831 patients with cataract and 1885 controls. Odds ratios (ORs) were 0.67 (95% confidence interval (CI) 0.52–0.85), 0.90 (95% CI 0.54–1.51), 0.52 (95% CI 0.32–0.85) and 0.72 (95% CI 0.56–0.92) for recessive, dominant, additive and allele contrast models, respectively. Sensitivity analysis indicated that the results of the meta-analysis were robust. No publication bias was observed.

Conclusions

The OGG1 gene Ser326Cys polymorphism was associated with ARC risk.

     

Comparison of visual outcomes and reading performance after bilateral implantation of multifocal intraocular lenses with bilateral monofocal intraocular lenses

Purpose

To compare the visual acuity outcomes, contrast sensitivity function (CS) and reading ability in patients with bilateral multifocal intraocular lenses and patients with bilateral monofocal lenses.

Setting

Vizyon Eye Center, Denizli, Turkey.

Design

Comparative case series.

Methods

Consecutive bilateral cataract patients having implantation of Acriva Reviol MFM 611 multifocal IOLs (Group A) or Acriva BB UD 613 monofocal IOLs (Group B) were included. Parameters analyzed 6 months postoperatively included monocular uncorrected distance (UDVA), binocular uncorrected intermediate (UIVA), binocular uncorrected near (UNVA), CS and bilateral reading performance using MN Read.

Results

The study evaluated 42 eyes in Group A and 40 eyes in Group B. There were no statistically significant differences in UDVA between two groups postoperatively (p = .39). Binocular UIVA and binocular UNVA are better in Group A (p = .00, p = .00). Under photopic and scotopic conditions, contrast sensitivity results were decreased in Group A, especially at high spatial frequencies. No statistically difference were found in reading acuity, critical print size and maximum reading speed between two groups (p = .57, p = .62, p = .22).

Conclusions

This study concludes that multifocal lenses are reliable and efficient replacements for reading glasses since they significantly improve the vision for near or intermediate distance activities.

     

A novel <Emphasis Type="Italic">C</Emphasis>x<Emphasis Type="Italic">50</Emphasis> (<Emphasis Type="Italic">GJA8</Emphasis>) p.H277Y mutation associated with autosomal dominant congenital cataract identified with targeted next-generation sequencing

Background

To unravel the molecular genetic background responsible for autosomal dominant congenital pulverulent nuclear cataracts in a four-generation Chinese family.

Methods

Family history data were collected, ophthalmological examinations were performed, and genomic DNA was extracted from peripheral blood of the family members. The candidate genes were captured and sequenced by targeted next-generation sequencing, and the results were confirmed by Sanger sequencing. The structure modelling of the protein was displayed based on Swiss-Model Server, and its possible changes in the secondary structure were predicted using Antheprot 2000 software. The chemical dissimilarity and possible functional impact of an amino acid substitution were performed with Grantham score, PolyPhen-2, and SIFT predictions. Protein distributions were assessed by confocal microscopy.

Results

A novel heterozygous c.829C?>?T transition that led to the substitution of a highly conserved histidine by tyrosine at codon 277 (p.H277Y) in the coding region of connexin50 (Cx50, GJA8) was identified. Bioinformatics analysis showed that the mutation likely altered the secondary structure of the protein by replacing the helix of the COOH-terminal portion with a turn. The mutation was predicted to be moderately conservative by Grantham score and to be deleterious by both PolyPhen-2 and SIFT with consistent results. In addition, when expressed in COS1 cells, the mutation led to protein accumulation and caused changes in Cx?50 protein localization pattern.

Conclusions

This is a novel missense mutation [c.829C?>?T, (p.H277Y)] identified in exon 2 of Cx50. Our findings expand the spectrum of Cx50 mutations that are associated with autosomal dominant congenital pulverulent nuclear cataract.

     

Assessment of corneal backward light scattering in the healthy cornea and factors affecting corneal transparency

Purpose

To quantify normative corneal optical density (COD) values of healthy individuals and to investigate alterations in the COD in relation to their ocular and demographic characteristics.

Study design

Prospective, cross-sectional, and observational.

Methods

In total, 588 eyes from 588 healthy participants with clear corneas were consecutively enrolled. Corneal densitometry values expressed in standardized grayscale units (GSU) from different corneal layers and zones obtained using the rotating Pentacam Scheimpflug system were analyzed.

Results

The mean (SD) COD over the 12-mm diameter area was 14.4?±?2.74 GSU. A significant positive correlation was found between the participants’ age and the total COD (r?=?0.756, P?<?.001). No significant differences were found between males and females with respect to COD (P?=?.51). No significant correlation was found between the COD measurements and refractive error, pachymetry, and keratometry (P?>?.05 for all comparisons). On the other hand, COD was negatively correlated with white-to-white (WTW) corneal diameter (r?=???0.415, P?<?.001). Moreover, the WTW corneal diameter was correlated with the COD in any zone and layer of the cornea (P?<?.05 for all comparisons).

Conclusions

Wide variations in COD can be detected even in corneas deemed clinically clear. Age and corneal diameter that seem to influence corneal transparency should be taken into account when evaluating corneal backscatter.

     

Methicillin resistance and biofilm production of <Emphasis Type="Italic">Staphylococcus epidermidis</Emphasis> isolates from infectious and normal flora conjunctiva

Purpose

Coagulase-negative staphylococci have been reported to be the most frequent cause of bacterial postoperative endophthalmitis. Biofilm formation is the major virulence factor of Staphylococcus epidermidis and is often associated with methicillin resistance. This study aims at evaluating the presence of biofilm-producing and methicillin resistance genes (mecA) in S. epidermidis.

Methods

S. epidermidis isolated from clinically infected sites (group 1) and from normal human conjunctiva (group 2) were studied. All the isolates were tested for their ability to produce biofilm by the conventional Christensen´s method and the presence of mecA by PCR using the 22-mer oligonucleotides as primers.

Results

In total 20 isolates from group 1 and 22 from group 2 were studied. Biofilm and mecA were detected in 15 (75 %) and in 14 (70 %) in group 1 as compared to 8 (36.3 %) and 4 (18.2 %) in group 2 (p = 0.016). Simultaneously, biofilm production and presence of mecA genes were observed in 13/20 (65.0 %) in group 1, and 4/22 (18.2 %) in group 2 (p = 0.002). Multi-resistance was observed in 55 % in group 1 and 9 % in group 2 (p = 0.002); 57 % of the biofilm-producing strains was multi-resistant in contrast to none of the non-producing strains. In all multi-resistant strains, biofilm production was seen.

Conclusions

Biofilm formation capacity was widely distributed, particularly among mecA (+) S. epidermidis strains, which also displayed a high diversity of antibiotic resistance profiles.

     

Effect of laser peripheral iridotomy using argon and neodymium-YAG lasers on corneal endothelial cell density: 7-year longitudinal evaluation

Purpose

To evaluate the changes in corneal endothelial cell density (ECD) over a 7-year period after laser peripheral iridotomy (LPI) using argon and neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers.

Study design

Retrospective case series.

Methods

Eyes that underwent prophylactic LPI using argon and Nd:YAG lasers were followed up for 7 years. Central corneal endothelial cells were observed by use of noncontact specular microscopy preoperatively and at 1 and 7 years postoperatively. Changes in ECD and the associations between preoperative ECD and the total energy of the Nd:YAG laser were evaluated.

Results

Fifty-one eyes of 51 patients were followed up for 7 years. The ECD significantly decreased after LPI (P < 0.049), and the reduction rate at 1 year after the surgery (1.69 ± 4.80%, 95% CI: 0.34%–3.04%) was significantly higher than the annual reduction rates after 1 year (0.17 ± 0.85%/y, P = 0.036, 95% CI: -0.07% to 0.41%). No association was found between the preoperative ECD and the total laser energy.

Conclusions

Long-term evaluation indicated that the reduction in ECD after argon-Nd:YAG laser LPI was present but small during the initial year and was negligible after 1 year.

     

The relationship between vascular endothelial dysfunction and treatment frequency in neovascular age-related macular degeneration

Purpose

To assess the correlation between endothelial dysfunction and frequency of antivascular endothelial growth factor (anti-VEGF) treatment for neovascular age-related macular degeneration (nAMD).

Methods

We examined 64 consecutive patients with nAMD who were evaluated for endothelial function by use of peripheral arterial tonometry (EndoPAT 2000; Itamar Medical, Caesarea, Israel) at Toyama University Hospital from January 2015. We tallied the number of anti-VEGF treatments between January 2014 and December 2015 and determined the correlation between the number of anti-VEGF injections and endothelial function expressed as the reactive hyperemia index (RHI). Multiple regression analysis was also performed to identify the independent predictors of a larger number of injections.

Results

The mean number of anti-VEGF injections was 8.2 ± 3.3. The mean lnRHI was 0.47 ± 0.17. The lnRHI correlated with the number of anti-VEGF injections (r = ?0.56; P = 0.030). The multiple regression analysis revealed that endothelial function, neovascular subtypes, and treatment regimens were associated with the number of injections.

Conclusions

Endothelial dysfunction may affect the efficacy of anti-VEGF therapy. Neovascular subtypes may also predict a larger number of injections.

     

Changes in the size of the foveal avascular zone after vitrectomy with internal limiting membrane peeling for a macular hole

Purpose

To determine the size of the foveal avascular zone (FAZ) before and after vitrectomy for a macular hole (MH).

Study Design

Retrospective case series study.

Methods

Twenty-five eyes of 25 patients with a unilateral MH that had undergone vitrectomy with internal limiting membrane peeling were studied. The unaffected 17 fellow eyes were studied in the same way. En face images of the parafoveal region were obtained by optical coherence tomography angiography, and the images were used to measure the FAZ before and 1 month after the vitrectomy. The relationships between the different FAZ sizes and the ocular parameters were determined by Pearson product moment correlation analysis.

Results

Compared with the preoperative superficial FAZ (sFAZ), the postoperative sFAZ was significantly reduced (P < 0.001). The postoperative sFAZ was significantly smaller than that of the fellow eye (P < 0.001). The size of the postoperative sFAZ was significantly correlated with that of the preoperative sFAZ, the postoperative foveal thickness (FT), and the sFAZ of the fellow eyes (r = 0.520, P = 0.008; r = ?0.515, P = 0.012; and r = 0.702, P = 0.002, respectively). The size of the postoperative deep FAZ (dFAZ) was significantly correlated with the postoperative FT and the dFAZ of the fellow eyes (r = ?0.441, P = 0.035; and r = 0.499, P = 0.049, respectively). However, no significant correlation was found between the size of the postoperative FAZ and the size of the preoperative MH.

Conclusions

MH closure leads to a significant decrease in the size of the FAZ symmetrical to the size of the fellow eye. The size of the postoperative FAZ is influenced by the postoperative FT independently of the size of the MH.

     

Corneal endothelial changes following a single session of selective laser trabeculoplasty for pseudoexfoliative glaucoma

Purpose

To evaluate corneal endothelial cell parameters after a single session of selective laser trabeculoplasty (SLT) in pseudoexfoliative glaucoma (PEG) patients.

Methods

Corneal endothelial cell parameters of 18 PEG patients were compared with 18 healthy subjects following SLT treatment. All patients underwent SLT treatment to 180 degrees of inferior trabecular meshwork. Corneal measurements were performed using specular microscopy (Noncon Robo SP8000, Konan Medical, Hyogo, Japan). Endothelial cell density (ECD), hexagonal cell ratio (HEX), coefficient of variation (CV) of the corneal endothelial cell layer and central corneal thickness of the patients were measured at each visit.

Results

There was a statistically significant decrease in ECD (p = 0.004) and a statistically significant increase in CV (p = 0.041) at superior cornea 1 week after SLT. They returned to pre-SLT values at 1 month. One hour post-SLT HEX of inferior cornea was statistically significantly reduced (p = 0.01). At central cornea, there was a significant increase in HEX after 1 week (p = 0.001). Post-SLT IOP showed a significant positive correlation with CV and significant negative correlation with HEX at superior and inferior cornea. There was no correlation between total laser energy used and endothelial cell parameters.

Conclusion

Effect of a single session of SLT on corneal endothelium of PEG patients appears to be transient, and superior cornea was more affected than central and inferior cornea. All parameters returned to pre-SLT values at 1 month after treatment.

     

The effectiveness of disc synoptoscope on patients with abnormal binocular vision: a prospective cohort study

Purpose

We performed a prospective cohort study to evaluate the effectiveness of disc synoptoscope on binocularity in patients with abnormal binocular vision.

Methods

39 eligible subjects were recruited for visual therapy with disc synoptoscope in treatment group and 38 were just observed as control.

Results

Simultaneous perception in treatment group was better than controls at 6-month visit (p < 0.05). Fusional amplitude improved in treatment group but decreased in control group at 3- and 6-months visits (p < 0.001). Near and distance stereopsis in treatment group were better than controls at 3- and 6-months (p < 0.05). The improvements of monocular and binocular acuity in treatment group were better than controls at 3- and 6-months (p < 0.05). Postoperative recurrence rate in treatment group was lower than controls (p < 0.05).

Conclusion

Visual therapy with disc synoptoscope is effective in improving short-term binocular vision for the patients with abnormal binocular vision; disc synoptoscope could serve as an effective home-based visual therapy instrument.

     

<Emphasis Type="Italic">Oestrus ovis</Emphasis> external ophtalmomyiasis: a case report in Burgundy France

Background

External ophtalmomyiasis (EOM) is a zoonosis related to the presence of Oestrus ovis larvae at the ocular level in small ruminants (i.e. ovine, caprine). In humans, EOM is a rare cosmopolitan disorder, mostly described in warm and dry rural areas in patients living close to livestock areas. In metropolitan France (excluding Corsica), EOM is an exceptional disease with less than 25 cases recorded since 1917.

Case presentation

We report a case of EOM in a 19-years old man in the last week of September 2016 in Burgundy.

Conclusion

The diagnosis of an EOM in Burgundy, a French region described as cold and humid, is surprising and could be due to a more marked climatic warming during the vegetative season in Burgundy resulting in the implantation of Diptera of the genus Oestrus sp. in this region.

     

Crucial role of P2X<Subscript>7</Subscript> receptor for effector T cell activation in experimental autoimmune uveitis

Purpose

To investigate the roles of P2X7 receptors (P2RX7) in the pathogenesis of experimental autoimmune uveoretinitis (EAU).

Study design

Experimental.

Methods

Either wild-type (P2rx7 ^+/+ ) or P2rx7-deficient (P2rx7 ^?∕? ) mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) peptide 1-20. Severity of EAU was evaluated clinically and histopathologically. The induction of IRBP-specific proliferation and cytokines in draining lymph nodes was assessed by enzyme-linked immunosorbent assays (ELISA). The frequency of activation markers was examined by flow cytometry. Furthermore, inhibitory roles of systemic administration of Brilliant Blue G (BBG), an antagonist for P2RX7, in EAU were also assessed in the wild-type mice.

Results

The severity of EAU in P2rx7 ^?∕? mice was reduced as compared with that in P2rx7 ^+/+ mice, both clinically and histopathologically. IRBP-specific proliferation in P2rx7 ^?∕? on day 16 was slightly decreased compared to that in P2rx7 ^+/+ mice. The induction of IRBP-specific interferon (IFN)-γ and interleukin (IL)-17 in P2rx7 ^?∕? mice on day 16 was lower than that in P2rx7 ^+/+ mice. The up-regulation of surface expression of activation markers such as CD25, CD44, and CD69 in response to TCR stimulation in P2rx7 ^?∕? mice was decreased as compared with that in P2rx7 ^+/+ mice. Furthermore, neutralization of P2RX7 in vivo by BBG suppressed EAU clinically and histopathologically. IRBP-specific IFN-γ and IL-17 induction in BBG-treated mice was significantly lower than that in vehicle-treated mice.

Conclusion

The results suggest that P2RX7 is a novel preventative therapeutic target for uveitis as it suppresses the effector functions of both Th1 and Th17 cell responses.