Exploring the Healthy Eye Microbiota Niche in a Multicenter Study.

PURPOSE: This study aims to explore and characterize healthy eye microbiota. METHODS: Healthy subjects older than 18 years were selected for this descriptive cross-sectional study. Samples were collected with an eSwab with 1 mL of Liquid Amies Medium (Copan Brescia, Italy). Following DNA extraction, libraries preparation, and amplification, PCR products were purified and end-repaired for barcode ligation. Libraries were pooled to a final concentration of 26 pM. Template preparation was performed with Ion Chef according to Ion 510, Ion 520, and Ion 530 Kit-Chef protocol. Sequencing of the amplicon libraries was carried out on a 520 or 530 chip using the Ion Torrent S5 system (Thermo Fisher; Waltham, MA, USA). Raw reads were analyzed with GAIA (v 2.02). RESULTS: Healthy eye microbiota is a low-diversity microbiome. The vast majority of the 137 analyzed samples were highly enriched with Staphylococcus, whereas only in a few of them, other genera such as Bacillus, Pseudomonas, and Corynebacterium predominate. We found an average of 88 genera with an average Shannon index of 0.65. CONCLUSION: We identified nine different ECSTs. A better understanding of healthy eye microbiota has the potential to improve disease diagnosis and personalized regimens to promote health.

Refractive corneal inlay implantation outcomes: a preliminary systematic review.

PURPOSE: To review all case series of refractive corneal inlay implantation: Flexivue (Presbia, Netherlands), Invue (BioVision, Brügg, Switzerland) and Icolens (Neoptics, Hünenberg, Switzerland) performed in presbyopia patients and to evaluate the reported visual outcomes. In addition, our aim is to provide assessment for complications and to report the satisfaction rates. METHODS: PubMed, Web of Science and Scopus databases were consulted using "refractive corneal inlay", "Flexivue Inlay", "Invue Inlay" and "Icolens inlay" as keywords. 147 articles were found, and they were assessed considering the inclusion and exclusion criteria. After filtering, this systemic review included ten articles, published between 2011 and 2020. RESULTS: 308 eyes from 308 participants were enrolled in this systematic review. Mean maximum follow-up was 13.9 months. Nine of the ten case series included used femtosecond laser for the corneal pocket creation. Mean pocket depth was 293.75 µm. 77.5% of the eyes reported a postoperative uncorrected near visual acuity of 20/32 or better, and 19.20% of the inlay-implanted eyes achieved an uncorrected distance visual acuity of 20/20 or better. The most prominent complications were halos, pain, photophobia, and poor distance visual acuity. 27 eyes (8.7%) had to be explanted due to complications, such as near-distance spectacle dependence or blurred distance vision. CONCLUSION: Refractive corneal inlay outcomes demonstrated high efficacy, safety, and satisfaction rates. Furthermore, it is a reversible technique. However, the findings must be viewed with caution due potential conflict of interest. Further research with higher sample size is needed to validate these findings.

Bowman's layer transplantation in advanced keratoconus; 18-months outcomes.

PURPOSE: To assess the outcome of isolated Bowman's layer transplantation (BLT) in advanced keratoconus in the patients not suitable for ultra violet cross-linking and intra stromal corneal ring segments. STUDY DESIGN: Nonrandomized Quasi-Experimental. MATERIALS AND METHODS: Mid corneal stromal dissection followed by implantation of manually isolated bowman layer from a donor into the recipient stromal pocket was performed in the Department of Ophthalmology Khyber Teaching Hospital Peshawar from September 2018 to October 2018 and followed up over 18 months. RESULTS: Eleven eyes of 11 patients, 8 male and 3 female within the age range of 7-28 years with progressive keratoconus went under BLT All keratometry values decreased after surgery. Mean anterior pre-operative SimK changed from 69.05 ± 10.85 D to 61.14 ± 6.23 D at 18 months post-operatively (P = 0.005). Means pre-operative Kmax value decreased from 77.24 ± 7.58 D to 71.07 ± 5.37 D at 18 months post-operatively (p = 0.060). The mean pre-operative posterior keratometry value changed from - 10.03 ± 0.88 to - 8.96 ± 1.06 D at 18 months post-operatively (P = 0.002). Mean pre-operative thinnest corneal thickness increased from 281.64 ± 196.86 um to 355.27 ± 19.17 um at 18th months post-operatively (P = 0.001). Pachymetry p-value pre-operative to 18 months (P = 0.001) was statistically significant. Mean anterior SimK at 6 months post-operatively, 60.55 ± 5.56D changed to 61.14 ± 6.23D at 18 months post-operatively (P = 0.000), Kmax at 6 months postoperative 71.60 ± 5.01 D changed to 71.07 ± 5.37 D at 18 months post-operatively (P = 0.008). Both anterior K values at 6 months and 18 months post-operatively showed less significant change, and the same was true for Kmax data at 6 months and 18 months post-operatively. P-values at 6 months to 18 months post-operatively for cornea back data remained (P = 0.001) unchanged. No complications were observed intra-operatively or post-operatively. CONCLUSION: Bowman layer transplantation is a unique surgical treatment for advanced keratoconus to stabilize progressive ectasia with fewer complications avoiding the need for penetrating or deep anterior lamellar keratoplasty.

Corneal densitometry patterns in Descemet membrane endothelial keratoplasty and Descemet stripping automated keratoplasty.

PURPOSE: To compare corneal densitometry in a consecutive series of 52 endothelial keratoplasties (DMEK/DSAEK) using a Scheimpflug-based device after six months of follow-up. METHODS: Corneal densitometry (CD) values of 102 eyes were divided into three main groups: 33 DMEKs, 19 DSAEKs, and 50 healthy eyes without previous ocular surgery. The CD values were then analyzed and compared between the groups. We measured three main layers in depth and four different concentric zones at 1, 3, and 6 months postoperatively. RESULTS: In the DMEK group, total CD significantly decreased from 38.02 ± 10.21 grayscale units (GSU) to 31.13 ± 9.25 GSU (P < 0.01) between the first and the sixth month postoperative. In the DSAEK group, we found significant changes only between the first and three months after surgery (from 42.62 ± 9.31 GSU to 38.71 ± 10.53 GSU (P < 0.01). Regarding the concentric zones, CD in the DMEK group significantly decreased in the central zone from 33.55 ± 12.07 GSU to 30.63 ± 10.15 GSU (P < 0.01) and significantly increased in the periphery from 30.63 ± 10.15 GSU to 36.72 ± 9.37 GSU, (P < 0.01). The DSAEK group showed no changes in the central zone (from 36.91 ± 13.80 GSU to 36.14 ± 11.47 GSU, P = 0.52) and CD significantly increased in the periphery (41.91 ± 9.28 GSU, P < 0.01). CONCLUSION: When comparing CD values in DMEK versus DSAEK, we found no differences by layers or at central-paracentral concentric zones, although CD differences in the peripheral zones were statistically significant. This finding may be attributed to the thicker graft at periphery with a delayed clearance and less anatomical interphase in DSAEK.

An artificial intelligence-based deep learning algorithm for the diagnosis of diabetic neuropathy using corneal confocal microscopy: a development and validation study.

AIMS/HYPOTHESIS: Corneal confocal microscopy is a rapid non-invasive ophthalmic imaging technique that identifies peripheral and central neurodegenerative disease. Quantification of corneal sub-basal nerve plexus morphology, however, requires either time-consuming manual annotation or a less-sensitive automated image analysis approach. We aimed to develop and validate an artificial intelligence-based, deep learning algorithm for the quantification of nerve fibre properties relevant to the diagnosis of diabetic neuropathy and to compare it with a validated automated analysis program, ACCMetrics. METHODS: Our deep learning algorithm, which employs a convolutional neural network with data augmentation, was developed for the automated quantification of the corneal sub-basal nerve plexus for the diagnosis of diabetic neuropathy. The algorithm was trained using a high-end graphics processor unit on 1698 corneal confocal microscopy images; for external validation, it was further tested on 2137 images. The algorithm was developed to identify total nerve fibre length, branch points, tail points, number and length of nerve segments, and fractal numbers. Sensitivity analyses were undertaken to determine the AUC for ACCMetrics and our algorithm for the diagnosis of diabetic neuropathy. RESULTS: The intraclass correlation coefficients for our algorithm were superior to those for ACCMetrics for total corneal nerve fibre length (0.933 vs 0.825), mean length per segment (0.656 vs 0.325), number of branch points (0.891 vs 0.570), number of tail points (0.623 vs 0.257), number of nerve segments (0.878 vs 0.504) and fractals (0.927 vs 0.758). In addition, our proposed algorithm achieved an AUC of 0.83, specificity of 0.87 and sensitivity of 0.68 for the classification of participants without (n = 90) and with (n = 132) neuropathy (defined by the Toronto criteria). CONCLUSIONS/INTERPRETATION: These results demonstrated that our deep learning algorithm provides rapid and excellent localisation performance for the quantification of corneal nerve biomarkers. This model has potential for adoption into clinical screening programmes for diabetic neuropathy. DATA AVAILABILITY: The publicly shared cornea nerve dataset (dataset 1) is available at http://bioimlab.dei.unipd.it/Corneal%20Nerve%20Tortuosity%20Data%20Set.htm and http://bioimlab.dei.unipd.it/Corneal%20Nerve%20Data%20Set.htm.

Assessment of visual morbidity amongst diabetic retinopathy at tertiary eye care center, Nepal: a cross-sectional descriptive study.

BACKGROUND: Diabetic retinopathy (DR) is one of the leading causes of preventable blindness in low and middle income countries. In Nepal, there are less studies regarding DR and they too are limited around Kathmandu valley. This study was done to assess visual morbidity in patients with DR at a peripheral tertiary eye care center of Nepal. METHODS: This was a prospective, hospital based, cross-sectional study in which all consecutive cases of DR were evaluated. DR was classified according to Early Treatment Diabetic Retinopathy Study Research Group - report no. 10 Table A5-1 (Modified Airlie House Classification). Data entry and analysis was done in an SPSS unit version 20. Wherever applicable, variables were set as 100 eyes. RESULTS: Total number of patients included in this study was 50. Commonest age group was 50-69 yrs. (43/77 yrs.; min/max) comprising 80% of the total population (n = 50) and the predominant population was male (76%). Non proliferative diabetic retinopathy (NPDR) was found in 69%, proliferative diabetic retinopathy (PDR) in 31% and advanced diabetic eye disease (ADED) in 3% (n = 100). CONCLUSIONS: All the stages of DR were present at significant proportions in this study, noteworthy was the percentage of PDR. This study shows an urgency to gather a national data on DR, raise awareness among diabetics and train effective man power at a local level to diagnose DR at an early stage.

Ray-Tracing Transepithelial Excimer Laser Central Corneal Remodeling Plus Pachymetry-Guided Accelerated Corneal Crosslinking for Keratoconus.

PURPOSE: The aim of this study was to report the 12 to 96 months results of a tissue-preservation algorithm based on ray-tracing-guided transepithelial excimer laser central corneal ablation (RT t-PRK) combined with individualized pachymetry-guided accelerated crosslinking (M nomogram ACXL) in young adult patients with stable keratoconus (KC). METHODS: This was a prospective interventional study including 38 eyes of 38 young adult patients (stage II KC) with a mean age of 35 years (range 26-46 years) who underwent simultaneous RT with t-PRK plus pachymetry-based ACXL in the worst eye. The treatments were performed using the iViS Suite iRES Excimer Laser (Ligi, Taranto, Italy). Ray-tracing-guided treatments were planned using the customized interactive programmed transepithelial ablation (CIPTA) 2 web software and diagnostic data were assessed by the Precisio 2 tomographer (Ligi, Taranto, Italy) and Sirius tomographer (C.S.O., Florence, Italy). The main outcome measures included uncorrected distance visual acuity, best spectacle-corrected visual acuity, Kmax, high-order aberrations, minimum corneal thickness, and posterior elevation, with a mean follow-up of 52 months (range 12-96 m). RESULTS: The mean UDVA improved + 3.5 ±1.28 Snellen lines (SL); 38% gained ≥ 4 ±1.34 SLs, 35% ≥ 3 ±1.21 SLs, 22% ≥ 2 ±1.12 SLs, and 5% ≥ 1 ±0.75 SLs. The mean best spectacle-corrected visual acuity increased by + 4.3 ±1.3 SL. Sixty-eight percent gained ≥ 4 ±0.88 SLs and 30% ≥ 3 ±0.78 SL. No SLs were lost. CONCLUSIONS: RT t-PRK plus ACXL significantly improved the quality of vision in patients with KC, preventing overcorrection and minimizing tissue consumption.

The Influence of Lid-Parallel Conjunctival Folds and Conjunctivochalasis on Dry Eye Symptoms with and Without Contact Lens Wear: A Review of the Literature.

INTRODUCTION: Lid-parallel conjunctival folds (LIPCOF) and conjunctivochalasis (CCH) are similar conditions that seem to be related to dry eye severity. In addition, there is a lack of studies on the topic of LIPCOF and CCH on dry eye symptoms in non-contact lens and contact lens (CL) wearers. Therefore, the aim of this study is to review the relationship of LIPCOF and CCH with dry eye symptoms in non-CL and CL wearers, as well as to report the treatment of dry eye disease (DED) in non-CL and CL wearers who present LIPCOF or CCH. METHODS: A literature review of full-length original studies in two databases, PubMed and Scopus, was performed. The search period included observational studies in humans published between April 21, 2009 and March 20, 2023. RESULTS: A total of 26 studies were included. The studies suggest that LIPCOF and CCH are significantly related to dry eye symptoms in non-CL and CL wearers. However, the impact of CL wear on LIPCOF and CCH may be complex and may vary depending on individual factors such as lens type, lens care regimen, and pre-existing ocular conditions. Regarding LIPCOF management, tear substitutes seem to significantly reduce LIPCOF and dry eye symptoms in non-CL wearers, while vectored thermal pulsation (VTP) and microblepharoexfoliation (MBE) are suggested as promising treatment for LIPCOF and dry eye symptoms in CL wearers. Regarding CCH management, surgical interventions may be effective in reducing CCH when medical treatments have no response. In addition, an ocular examination by slit lamp is necessary to distinguish both conditions. CONCLUSIONS: Tear substitutes, VTP, MBE, and fitting CLs with low coefficient of friction (CoF) seem to reduce and prevent LIPCOF. However, surgical treatment options seem to be more effective in the complete elimination of CCH. An adequate evaluation and differentiation between LIPCOF and CCH are important, and they should be considered by practitioners in managing dry eye symptoms in non-CL and CL wearers.

Efficacy of bilateral OC-01 (varenicline solution) nasal spray in alleviating signs and symptoms of dry eye disease: A systematic review.

PURPOSE: To comprehensively review the efficacy and safety of OC-01 varenicline nasal spray versus vehicle nasal spray (VNS) in the treatment in dry eye disease (DED). METHODS: A systematic review that included full-length randomized controlled studies (RCTs), as well as post hoc analyses of RCTs reporting new findings on OC-01 VNS treatment in three databases, PubMed, Scopus and Web of Science, was performed according to the PRISMA statement. The search period included studies published between December 2021 and September 2023. The Cochrane risk of bias tool was used to analyze the quality of the studies selected. RESULTS: A total of 8 studies were included in this systematic review. OC-01 VNS treatment achieved higher improvement than vehicle in all reported variables. The mean differences between both groups were in favor of OC-01 VNS treatment and were as follow: eye dryness score base on a visual analogue scale (EDS-VAS) of -7.5 ± 2.2 points [-11.6 to -5.6], Schirmer test (ST) with anesthesia of 6.6 ± 2.3 mm [4.9 to 11.8] and total corneal fluorescein staining (tCFS) of -1.2 ± 0.01 points [-1.2 to -1.1]. Similar improvements were reported with OC-01 VNS 0.03 mg and 0.06 mg. Adverse events (AEs) were 15.5 ± 19.4 % [-13 to 80.5] higher in the OC-01 VNS group with an overall adherence > 93 %. CONCLUSIONS: OC-01 VNS improves dry eye symptoms and signs with a satisfactory tolerability. Therefore, OC-01 VNS seems to be a safe and effective treatment that could be recommended in patients with DED. This new treatment could be particularly useful in those patients who have difficulties with the administration of traditional topical therapies.

Efficacy and Safety of Quantum Molecular Resonance Electrotherapy in Patients with Aqueous-Deficient, Evaporative and Mixed-Type Dry Eye: A Randomized Interventional Study.

INTRODUCTION: To evaluate the efficacy and safety of Quantum Molecular Resonance (QMR) treatment in patients with severe dry eye disease (DED), as well as its effects on aqueous-deficient (ADDE), evaporative (EDE), and mixed (MDE) dry eye. METHODS: In this prospective, interventional study, 81 patients were randomly allocated to received four treatment sessions of QMR at 1-week intervals (Rexon-Eye®, Resono Ophthalmic, Trieste, Italy) (QRM group) or tear substitute four times daily, containing 0.15% sodium hyaluronate and 3% trehalose (Thealoz Duo®, Thea Pharma, France) (SH-TH group). Outcome measures included ocular surface disease index (OSDI) questionnaire, tear meniscus height (TMH), tear breakup time (TBUT), non-invasive breakup time (NIBUT), corneal fluorescein staining (CFS), lipid layer thickness (LLT), tear film osmolarity (OSM), and meibomian gland dysfunction (MGD) grade, which were assessed at baseline and 1-month and 3-month follow-up. RESULTS: The QMR group achieved better improvements than the SH-TH group in OSDI and SANDE questionnaires, NIBUT, LLT, and CFS. The mean differences between the groups were as follows: OSDI (- 12.4 ± 0.25 points, P = 0.01), SANDE (10.6 ± 1.7 points, P = 0.01), NIBUT (2 ± 0.25 s, P = 0.01), LLT (18.7 ± 0.7 nm, P = 0.01), and CFS (1.2 ± 0.1 points, P = 0.02). In subgroups analysis, QMR treatment demonstrated a beneficial role to improve DED symptoms and signs in ADDE, EDE, and MDE. CONCLUSION: QMR is an effective and well-tolerated treatment that seems to improve DED symptoms and signs in patients with severe DED. However, further studies are needed to confirm this. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT06119386.

Evaluating GlicoPro Tear Substitute Derived from Helix aspersa Snail Mucus in Alleviating Severe Dry Eye Disease: A First-in-Human Study on Corneal Esthesiometry Recovery and Ocular Pain Relief.

Background: To evaluate the effects of 10% GlicoPro tear substitute therapy in patients with severe dry eye disease (DED). Methods: In this prospective longitudinal study, 30 individuals receiving 10% GlicoPro four times daily for DED were evaluated. The ocular surface disease index (OSDI) questionnaire, average non-invasive break-up time (A-NIBUT), non-anesthetic and anesthetic corneal esthesiometry (CE), ocular pain, and the presence of conjunctivochalasis (CCH) were used as clinical endpoints. Treatment compliance using dosing diaries and AEs was assessed. Results: A significant improvement was observed in the clinical endpoints: the ΔOSDI questionnaire was -39.27 ± 13.22 [-65 to -15] points, ΔA-NIBUT was 3.10 ± 1.31 [1 to 5] s, Δnon-anesthetic CE was 14 ± 6.35 [5 to 25] mm, and Δanesthetic CE was 13 ± 5.35 [5 to 20] mm (p < 0.001 for all comparisons). Ocular pain was reduced in 92.5% of the patients at the end of the follow-up. However, there was no change in the presence of CCH. In addition, all the patients were fully compliant with the dosing and no AEs related to the use of the 10% GlicoPro tear substitute were reported. Conclusions: The 10% GlicoPro tear substitute has the potential to achieve beneficial effects in ocular surface treatments.

Topical Antiseptics in Minimizing Ocular Surface Bacterial Load Before Ophthalmic Surgery: A Randomized Controlled Trial.

PURPOSE: To investigate the reduction of the ocular surface bacterial load induced by 2 commercially available ophthalmic antiseptic formulations, povidone-iodine (PVI) 0.6% and chlorhexidine (CLX) 0.02%, before ocular surgery. DESIGN: Randomized controlled trial. METHODS: Seventy adult patients undergoing intraocular surgery (phacoemulsification) were randomized to receive in the index eye PVI (group A) 4 times a day for 3 days or CLX (group B) 4 times a day for 3 days before surgery. The untreated eye was used as control. A conjunctival swab was taken in both eyes before (T0) and after (T1) therapy. Microbial DNA was quantified with real-time polymerase chain reaction (PCR) analysis. The Mick algorithm was used to compare the abundance of each genus/genera against the distribution of abundances from the reference. At T1, patients filled a questionnaire to evaluate therapy-induced symptoms. Primary outcome was the reduction of bacterial DNA at T1 (microbial load), vs control arm, expressed as mean number of real-time PCR cycle times (CTs). Secondary outcomes were taxonomic composition, differential abundance, and therapy-induced ocular symptoms. RESULTS: The T0-T1 difference in CT was significant in group B, but not in group A (mean [95% CI], 0.99 [0.33] vs 0.26 [0.15], P < .001, and 0.65 [0.3] vs 0.45 [0.41], P = .09, respectively). The taxonomic composition, alpha, and beta diversity remained consistent at all time points in both groups. The rate of patients reporting therapy-induced ocular symptoms and the mean discomfort grade were greater in group A than in group B (97% vs 26% and 4.97±2.48 vs 0.66±1.53, respectively). CONCLUSIONS: Compared with PVI 0.6%, CLX 0.02% induced a greater reduction of ocular surface bacterial load, with no significant alterations of the taxonomic composition. Moreover, CLX was better tolerated than PVI.

Infectious Keratitis: Characterization of Microbial Diversity through Species Richness and Shannon Diversity Index.

Purpose: To characterize microbial keratitis diversity utilizing species richness and Shannon Diversity Index. Methods: Corneal impression membrane was used to collect samples. All swabs were processed and analyzed by Biolab Laboratory (level V-SSN Excellence: ISO 9001:2015), Biolab Srl (Ascoli Piceno, Italy). DNA extraction, library preparation, and sequencing were performed in all samples. After sequencing, low-quality and polyclonal sequences were filtered out by the Ion software. At this point, we employed Kraken2 for microbial community analysis in keratitis samples. Nuclease-free water and all the reagents included in the experiment were used as a negative control. The primary outcome was the reduction in bacterial DNA (microbial load) at T1, expressed as a percentage of the baseline value (T0). Richness and Shannon alpha diversity metrics, along with Bray-Curtis beta diversity values, were calculated using the phyloseq package in R. Principal coordinate analysis was also conducted to interpret these metrics. Results: 19 samples were included in the study. The results exhibited a motley species richness, with the highest recorded value surpassing 800 species. Most of the samples displayed richness values ranging broadly from under 200 to around 600, indicating considerable variability in species count among the keratitis samples. Conclusions: A significant presence of both typical and atypical bacterial phyla in keratitis infections, underlining the complexity of the disease's microbial etiology.

Expression of VEGF-A, Otx homeobox and p53 family genes in proliferative vitreoretinopathy.

INTRODUCTION: Proliferative vitreoretinopathy (PVR) is a severe inflammatory complication of retinal detachment. Pathological epiretinal membranes grow on the retina surface leading to contraction, and surgery fails in 5% to 10% of the cases. We evaluated the expression of VEGF-A, Otx1, Otx2, Otx3, and p53 family members from PVR specimens to correlate their role in inducing or preventing the pathology. METHODS: Twelve retinal samples were taken from patients affected by PVR during therapeutic retinectomies in vitreoretinal surgery. Gene expression was evaluated using quantitative real-time reverse transcriptase PCR analysis and immunohistochemistry, using four healthy human retinae as control. RESULT: Controls showed basal expression of all genes. PVR samples showed little or no expression of Otx1 and variable expression of VEGF-A, Otx2, Otx3, p53, and p63 genes. Significant correlation was found among VEGF-A, Otx2, p53, and p63 and between Otx1 and Otx3. CONCLUSIONS: Otx homeobox, p53 family, and VEGF-A genes are expressed in PVR human retina. We individuated two possible pathways (VEGF-A, Otx2, p53, p63 and Otx1 and Otx3) involved in PVR progression that could influence in different manners the course of the pathology. Individuating the genetic pathways of PVR represents a novel approach to PVR therapies.

Epithelial downgrowth leading to graft rejection after penetrating keratoplasty.

PURPOSE: To report a case of epithelial downgrowth after penetrating keratoplasty. CASE DESCRIPTION: A 58-year-old man presented with graft rejection in his three-month-old, repeat penetrating keratoplasty. Examination revealed centripetal opacification of the posterior cornea due to deep epithelization. He had new retro-corneal membranes and anterior uveitis. Specular microscopy and anterior segment optical coherence tomography were performed, and a clinical diagnosis of epithelial downgrowth was made. The patient had intracameral injections with 5-fluorouracil (5FU) and achieved resolution of intraocular findings after treatment. CONCLUSIONS: Epithelial downgrowth is an uncommon complication of penetrating keratoplasty. It affects the patients' visual acuity and graft survival. Clinical observation is preferred in severe cases due to the high risk of intraocular damage; intracameral 5FU promises to be a good option in these cases.

The role of matrix metalloproteinases in infectious corneal ulcers.

During infectious keratitis, the production of collagenolytic and inflammatory substances, along with increased corneal matrix metalloproteinase (MMP) activity, induces the degradation of corneal collagen and may cause postkeratitis complications, such as opacity, thinning, and corneal perforation. MMPs, especially MMP-2 and MMP-9, are overexpressed in infectious keratitis and sustained over time by inflammatory and nonmicrobial mechanisms. The high MMP levels are correlated with excessive corneal destruction in bacterial, herpetic, fungal, and acanthamoeba infections. Nonspecific treatments, such as tetracyclines, particularly doxycycline, or corticosteroids, are used as adjuvants to antimicrobials to alleviate the disproportionate degradation and inflammation of the corneal layers caused by corneal MMPs and decrease the recruitment and infiltration of inflammatory cells. Treatments showing inhibition of specific MMPs (Galardin, ZHAWOC7726), interfering with pro-MMP activation (EDTA, ascorbic acid), or showing anticytokine effect (epigallocatechin-2-gallate, TRAM-34) have been reported. Other treatments show a direct action over corneal collagen structure such as corneal cross-linking or have been associated with reduction of MMP levels such as amniotic membrane grafting. Although the use of these drugs has been shown in studies to be effective in controlling inflammation, especially in experimental ones, robust studies are still needed based on randomized and randomized clinical trials to demonstrate their potential effect as adjuvants in the management of infectious keratitis.

Assessing the Effects of 0.3% Carboxymethylcellulose Tear Substitute Treatment on Symptoms and Signs of Dry Eye Disease in Elderly Population: A Prospective Longitudinal Study.

BACKGROUND: We aimed to evaluate the effects of 0.3% carboxymethylcellulose (CMC) tear substitute treatment in dry eye disease (DED), as well as treatment compliance and adverse events (AEs). METHODS: In this prospective, longitudinal study, a total of 30 eyes receiving 0.3% CMC tear substitute four times daily for DED were evaluated. Clinical endpoints included an ocular surface disease index (OSDI) questionnaire, average non-invasive tear film break-up time (A-NIBUT), lipid layer thickness (LLT), and a Schirmer test with anesthesia (ST). Treatment compliance and AEs were also assessed. All evaluations were performed at 2, 4, and 12 weeks of follow-up. RESULTS: At the end of the follow-up, significant improvement was observed in all clinical endpoints with the following mean values: ΔOSDI questionnaire of -22.53 ± 14.68 points, ΔA-NIBUT of 4.81 ± 2.88 s, ΔLLT of 5.63 ± 6.53 nm, and ΔST of 2.8 ± 2.1 mm (p < 0.001 for all comparisons). Although repeated measures analysis showed that all clinical endpoints presented statistically significant differences (p < 0.001 for all comparisons LLTBaseline-LLT2-weeks (p = 0.460) and LLT4-weeks-LLT12-weeks (p = 0.071) were the only pairs of measures that reported non-statistically significant differences). In addition, treatment compliance was 94.3 ± 5.2% and transient AEs related to the use of 0.3% CMC tear substitute were reported. CONCLUSIONS: 0.3% CMC tear substitute treatment seems to achieve beneficial effects on the OSDI questionnaire, A-NIBUT, LLT, and ST. However, further studies at this concentration are needed to confirm these results.

Shotgun metagenomic sequencing in culture negative microbial keratitis.

PURPOSE: To evaluate the microbiota of culture negative Corneal Impression Membrane (CIM) microbial keratitis samples with the use of shotgun metagenomics analysis. METHODS: DNA of microbial keratitis samples were collected with CIM and extracted using the MasterPure™ Complete DNA and RNA Purification Kit (Epicentre). DNA was fragmented by sonication into fragments of 300 to 400 base pairs (bp) using Bioruptor® (Diagenode, Belgium) and then used as a template for library preparation. DNA libraries were sequenced on Illumina® HiSeq2500. The resulting reads were quality controlled, trimmed and mapped against the human reference genome. The unmapped reads were taxonomically classified using the Kraken software. RESULTS: 18 microbial keratitis samples were included in the study. Brevundimonas diminuta was found in 5 samples while 6 samples showed the presence of viral infections. Cutibacterium acnes, Staphylococcus aureus, Moraxella lacunata and Pseudomonas alcaligenes were also identified as the presumed putative cause of the infection in 7 samples. CONCLUSIONS: Shotgun sequencing can be used as a diagnostic tool in microbial keratitis samples. This diagnostic method expands the available tests to diagnose eye infections and could be clinically significant in culture negative samples.