Case Report: Role of Anterior Segment Optical Coherence Tomography for Managing Failed Endothelial Keratoplasty Graft.

SIGNIFICANCE: Some patients show poor visual outcomes after Descemet stripping automated endothelial keratoplasty. In such cases, secondary Descemet membrane endothelial keratoplasty can be performed to achieve complete visual recovery. Anterior segment optical coherence tomography (AS-OCT) is a valuable tool for the follow-up of posterior lamellar keratoplasty outcomes and complications. PURPOSE: This study aimed to report the clinical outcome of secondary Descemet membrane endothelial keratoplasty for managing poor visual results in a patient with graft failure after a previous Descemet stripping automated endothelial keratoplasty, highlighting the importance of AS-OCT in the follow-up of endothelial keratoplasty. CASE REPORT: A 38-year-old woman with high myopia underwent Descemet stripping automated endothelial keratoplasty for bullous keratopathy after explantation of an angle-supported phakic intraocular lens. Two years after keratoplasty, the patient experienced poor visual acuity (counting fingers), and significant corneal edema was observed on clinical examination hindering visualization of the anterior chamber structures. Anterior segment optical coherence tomography showed a failed and thickened graft adhering well to the recipient cornea in an anterior chamber without other comorbidities. Therefore, the graft was removed and replaced with a Descemet membrane endothelial keratoplasty graft without any complications. One year later, the clinical outcome was evaluated by comparing the pre-operative and post-operative best-corrected visual acuity, biomicroscopy findings, endothelial cell density, and corneal central thickness. CONCLUSIONS: Anterior segment optical coherence tomography is an important tool when deciding on the surgical technique to be applied and for the post-surgical monitoring of endothelial corneal grafts. This case demonstrates the successful management of Descemet stripping automated endothelial keratoplasty graft failure with Descemet membrane endothelial keratoplasty graft, highlighting the importance of AS-OCT in detecting complications such as graft dislocation and primary graft failure. In addition, corneal thickness measured using AS-OCT serves as a critical predictor of graft failure, as observed in this case.

Refractive changes and visual quality in patients with corneal edema after cataract surgery.

BACKGROUND: To assess visual quality and stabilization of refractive changes in corneal edema patients after cataract surgery, using visual acuity (VA) and contrast sensitivity measurements. METHODS: Sixty-one eyes were analysed, twenty-three with and thirty-eight without corneal edema. Uncorrected and corrected distance VA (UDVA and CDVA) were determined with an EDTRS chart, the contrast sensitivity function (CSF) under photopic and mesopic illumination conditions with a CVS-1000e chart, clinical refraction, and corneal topography. Measurements were taken preoperatively, 1-2 days, 1 and 3-months after surgery. Clinical refraction was converted to vector notation (M, J0, J45) and SPSS v26.0 was used for data analysis. RESULTS: An improvement of VA was observed through the postoperative period; changes between visits were significant for CDVA in both groups and for UDVA in the edema sample. Significant astigmatic changes (J0,J45) between visits were not observed, but M values showed a hyperopic tendency in the edema group and a myopic shift in the control group that did not change between visits, with statistically significant differences between groups. Controls had significantly better contrast sensitivity at high spatial frequencies. Under mesopic conditions, global contrast sensitivity losses were observed in the edema group, which improved between visits in the middle frequency range. CONCLUSION: Corneal edema patients had a significant reduction of CDVA, and frequency-selective sensitivity losses that evidence a visual quality loss. Clinical refraction may improve visual quality, but in edema patients these losses are related to corneal changes, which did not change at three months after surgery.

The Link between Anterior Scleral Thickness, Corneal Biomechanical Response, and Ocular Parameters.

INTRODUCTION: This study aimed to assess anterior scleral thickness (AST) across diverse scleral meridians and to evaluate the relationship with corneal biomechanical response and several ocular parameters. METHODS: This prospective nonrandomized study comprised 50 eyes of 50 patients (mean age, 29.02 ± 9.48 years). AST was measured meridionally at three scleral locations (1, 2, and 3 mm posterior to the scleral spur) using swept-source optical coherence tomography. A multivariate model was created to associate AST with several ocular parameters. Principal component analysis (PCA) was used to reduce linearly the dimensionality of seven biomechanical input metrics to two significant components, C1 and C2. Two multivariate analyses were performed to associate C1 and C2 with AST and ocular parameters. RESULTS: AST was thickest in the inferior (581 ± 52 µm) and thinnest in the superior meridian (441 ± 42 µm) when compared to all meridians (p < 0.001) and similar in the nasal (529 ± 53 µm) and temporal (511 ± 59 µm) meridians (p > 0.05). The sclera exhibited the thinnest point 2 mm posterior to the scleral spur (p < 0.001). The AST was significantly linked with axial length, central corneal thickness, and intraocular pressure (p < 0.001). The PCA showed that C1 accounts for 53.84%, whereas C2 for the 16.51% of the total variance in the original variables. The C1 model was significantly associated with AST along all meridians (p < 0.001). The partial correlation was moderate in the nasal (r = -0.36, p < 0.001) and inferior (r = -0.26, p = 0.004) meridians, whereas weak in the temporal (r = -0.14, p = 0.05) and superior (r = -0.15, p = 0.05) meridians. CONCLUSIONS: The relationship between the new biomechanical component and the AST provides the first evidence of the association of AST with the corneal response parameters which should be considered in corneal response interpretation. Tissue thickness varied significantly among meridians supporting the asymmetrical expansion of the ocular globe. The AST was associated with several ocular parameters.

Case Report: Role of Anterior Segment Optical Coherence Tomography in Late-onset Capsular Block Syndrome.

SIGNIFICANCE: We report the use of anterior segment optical coherence tomography (AS-OCT) as a valuable tool for capsular block syndrome diagnosis and follow-up. PURPOSE: The purposes of this study are to report a case of late-onset capsular block syndrome or lacteocrumenasia and to describe differential diagnosis with other more common phacoemulsification complications such as intraocular lens (IOL) or posterior capsule opacification. CASE REPORT: We report the case of a 56-year-old man with a clinical history of cataract surgery in his left eye. Five years after cataract surgery, he complained of blurred vision and was referred for IOL removal to our hospital. After careful slit-lamp examination, we found that the lens was clear, and opacity belonged to the accumulation of a whitish material in the capsular bag behind the lens. AS-OCT gave the definite diagnosis of capsular block syndrome. Intraocular lens removal had been wrongly indicated, and we treated our patient by YAG laser posterior capsulotomy. AS-OCT confirmed the absence of a further accumulated material, so no other interventions were needed. After treatment, best-corrected visual acuity improved from 0.48 to 0.1 logMAR. CONCLUSIONS: Capsular block syndrome is a rare late-onset complication of cataract surgery causing a deep visual acuity decay. A precise slit-lamp examination and AS-OCT, together, avoid misdiagnosis and unnecessary surgical treatment, which may be needed in case of IOL opacity or fibrotic-like lacteocrumenasia. AS-OCT also helps in determining the treatment outcome. Immediate best-corrected visual acuity improvement is reached after a successful intervention.

Fitting Scleral Lenses Less Than 15 mm in Diameter: A Review of the Literature.

OBJECTIVE: To perform a comprehensive review of the current and historical scientific literature on fitting small scleral lenses (diameter <15 mm) and clarifying their advantages and disadvantages, in addition to their clinical applications. METHODS: The literature search was performed through PubMed from MEDLINE. RESULTS: Eleven studies of case series (258 eyes) were found. Indications were similar to those of larger scleral lenses, 74% for corneal irregularities (mainly keratoconus), whereas 26% for ocular surface diseases. In the studies on cases of irregular corneas, visual acuity improved significantly regarding the values before and after fitting the lenses (mean, 0.4-0.03 logMar, respectively). Moreover, no significant adverse effects on the ocular surface were reported, and most studies reported over 10 hr (or thereabouts) of daily wear without removing the lenses. A better corneal physiology and visual quality, easier fitting procedure and lens handling, and prolonged hours of wear are proposed as significant advantages over larger scleral lenses. CONCLUSION: Small scleral lenses may be a safe and healthy alternative option to treat corneal irregularities and ocular surface diseases. These lenses can be fitted when it is necessary to improve visual quality and corneal physiology, when discomfort with other contact lenses is experienced, or when patients have difficulty handling larger diameters of scleral lenses. However, fitting these lenses is not suggested in severe cases or when it is not a reasonable clinical option.

Locking Y Lateral Canthopexy as a Treatment for Dry Eye Disease Caused by Eyelid Malposition.

PURPOSE: The signs and symptoms of dry eye disease (DED) can affect the quality of life of patients. This study analyzes whether locking Y lateral canthopexy improves patients' quality of life and in what way it does so (based on the ocular surface disease index questionnaire) and DED signs (measured by the fluorescein breakup time, tear osmolarity, Schirmer test, and corneal staining) in patients with DED caused by a eyelid malposition or impaired blink dynamics. METHODS: This was a case-control study. Forty eyes of 20 patients with DED and lateral canthal disinsertion examined at the University Hospital La Ribera during a 1-year period from November 2016 to November 2017. The 40 eyes were divided into 2 groups: Group 1 eyes that underwent locking Y lateral canthopexy (i.e., a plication of the superficial lateral canthal tendon to the lateral orbital rim periosteum); and group 2 eyes that underwent observational treatment, without surgery. Symptoms and signs in OU were recorded separately at baseline and 1 month after surgery. RESULTS: One month after surgery, the ocular surface disease index reduced in group 1 eyes when compared with those of group 2 (p = 0.001), fluorescein breakup time showed an improvement in the operated eyes (group 1) (p < 0.001) and corneal staining was reduced in group 1 after surgery (p = 0.012). The osmolarity results did not change when compared with eyes from group 2 (p < 0.001). CONCLUSIONS: Locking Y lateral canthopexy is an effective surgical technique for treating patients with evaporative dry eye caused by a lateral canthal tendón disinsertion by restoring proper eyelid closure and improving blinking dynamics. It improves DED signs and symptoms, thereby enhancing the quality of life of patients.

Which are the best parameters to obtain proteins and malondialdehyde from a tear sample?

Predictive, preventive and personalized medicine (PPPM) is a current concept in healthcare based on the analysis of biomarkers through non-invasive methods. Biomarkers for inflammation and oxidative stress are especially used for screening. Quantification of tear total protein content is important to identify potential, specific biomarkers, such as malondialdehyde concerning oxidative stress. The Schirmer strip test is an accessible and simple method for tear analysis. However, it is limited by the low concentration of biomarkers in the human tear. In this preliminary study, different procedures were compared for the extraction of tear proteins and malondialdehyde. Schirmer strips were used to obtain tears from healthy subjects. Ionic strength and surfactant agents were assessed, as well as different centrifugation parameters. Finally, several volumes of n-butanol on the process of malondialdehyde extraction were evaluated. The results showed that ionic strength strongly influences the extraction process, although most studies have suggested that surfactant agents are the most relevant factor; the most efficient results were obtained using a 2 M solution of NaCl in phosphate buffered saline. Regarding centrifugation, leaving the Schirmer strip tip left hanging outside the tube cap and using 1000 rpm was the best option, which is a lower centrifugation speed than the usually reported on literature. Moreover, 250 µL was the optimal n-butanol volume for malondialdehyde extraction. The importance of this study relies on the increasing relevance of the biomarkers in the field of PPPM and the need of a standardized method to extract biomarkers from the tears, to optimise its use.

Impact of Corneoscleral Contact Lens Usage on Corneal Biomechanical Parameters in Keratoconic Eyes.

OBJECTIVE: To analyze the changes in corneal biomechanical parameters of keratoconic eyes with and without intracorneal ring segment (ICRS) implants after 1 year of corneoscleral contact lens (CScL) wear. METHODS: Seventy-four eyes of 74 patients were divided into three groups: healthy subjects (29 eyes, control group), and 2 groups of subjects with keratoconic eyes (one group of 20 eyes with ICRS implants and one of 25 eyes without them), which were fitted with CScL. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated before fitting CScL and after 1 year of CScL wear. In addition, endothelial cell count (ECC) and central corneal thickness (CCT) were also recorded. RESULTS: Corneal biomechanical parameters were lower in keratoconic corneas than in healthy corneas. Keratoconic eyes with ICRS implants had lower values than eyes without them for CH (mean±SD, 8.09±1.29 vs. 8.63±1.5 mm Hg, respectively, P=0.120), CRF (6.99±1.38 vs. 8.37±1.52 mm Hg, respectively, P=0.03), and also for CCT and ECC. Data for IOPcc were similar in all groups. After 1-year wearing CScL, no statistically significant differences in corneal biomechanical parameters were registered in any of the groups (all P>0.05), although slight differences (0.13-0.27 mm Hg) were found. CONCLUSION: The viscoelasticity properties of the cornea did not change significantly when wearing corneoscleral contact lenses for 1 year, and therefore, these lenses seem to be safe and healthy and are a reasonable alternative option for keratoconus management.

Comparison of the Ultraviolet Light Filtering across Different Intraocular Lenses.

SIGNIFICANCE: We have analyzed the ultraviolet transmittance of some commercial intraocular lenses (IOLs). The results show differences of wavelength cutoff among them. PURPOSE: The purpose of this study was to measure and compare the ultraviolet light transmittance of different IOLs made out of acrylic hydrophobic, hydrophilic, and hydrophilic with hydrophobic surface materials from different manufacturers. METHODS: The spectral transmission curves of eight monofocal IOLs with the same dioptric power of +20.0 diopters were measured using a PerkinElmer Lambda 35 ultraviolet/visible spectrometer. Two IOLs of each type were tested three times. The ultraviolet cutoff wavelength at 10% transmission and the mean values were calculated. RESULTS: All lenses prevented transmission of ultraviolet C (200 to 280 nm) and B radiation (280 to 315 nm). However, not all IOLs provided the same filtering properties in ultraviolet A (315 to 380 nm). Within the ultraviolet A range, the ultraviolet radiation cutoff wavelength of 10% ranges from approximately 360 to 400 nm. HOYA iSert 250 provided a cutoff wavelength of 398.4 nm; AcrySof SA60AT, 396.2 nm; AcrySof SA60WF, 395.7 nm; CT Asphina 404, 378.34 nm; Tecnis ZCB00, 377.70 nm; CT Lucia 607P, 379 nm; C-Flex 570C, 377 nm; and enVista MX60, 360 nm. CONCLUSIONS: Intraocular lenses of different materials and manufacturers have different ultraviolet transmission characteristics. AcrySof (SA60AT and SA60WF) and HOYA iSert 250 provided the highest ultraviolet radiation transmission; the cutoff wavelength of 10% is close to 400 nm. In contrast, enVista IOL showed the lowest ultraviolet radiation cutoff.

Corneal Biomechanical Parameters With Corneoscleral Contact Lenses in Post-Laser In Situ Keratomileusis Eyes.

OBJECTIVE: To evaluate corneal biomechanical parameters wearing corneoscleral contact lenses (CScL) in patients with irregular corneas after laser in situ keratomileusis (LASIK). METHODS: Data from patients fitted with CScL because of corneal surface irregularities after complicated LASIK surgery were selected by two eye clinics. Previously and after 1 year of CScL fitting, corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and central corneal thickness were evaluated. In addition, visual acuity, subjective comfort, and wearing time CScL were reported. RESULTS: The study comprised 27 eyes. Statistically significant differences were found in visual acuity between the best spectacle-corrected vision and after CScL fitting [mean±SD, 0.16±0.03 logarithm of the minimum angle of resolution (logMAR) and 0.01±0.06 logMAR, respectively; P<0.001]. In addition, the patients reported high subjective comfort ratings (22 eyes were comfortable or very comfortable) and prolonged usage times (mean±SD, 12.67±1.98 hr of continuous wear a day). Statistically significant differences were found in the CRF between before CScL fitting and after 1 year of CScL wear (mean±SD, 7.57±0.87 and 7.68±0.84 mm Hg, respectively; P=0.015). Central corneal thickness, CH, and IOPcc showed slight differences after 1 year of CScL wear (1.78 µm, 0.04 and 0.21 mm Hg, respectively). CONCLUSION: Corneal biomechanical parameters increased slightly, although significantly for CRF, apparently without adverse clinical effects in post-LASIK eyes with irregular corneas after wearing CScL for 1 year.

Post-LASIK Visual Quality With a Corneoscleral Contact Lens to Treat Irregular Corneas.

OBJECTIVE: To evaluate the visual quality results of fitting a corneoscleral contact lens with multiaspheric geometry design (MAGD CScL) in subjects with irregular corneas after laser-assisted in situ keratomileusis (LASIK) surgery. METHODS: From a database of patients evaluated for scleral contact lenses, we identified those with irregular corneas and visual problems after they underwent LASIK surgery for correcting myopia. They manifested unsatisfactory visual quality with their current contact lenses or glasses. Therefore, a MAGD CScL was fitted and monitored according to standardized fitting methodology. A diagnostic trial set was used in the fitting process. Visual acuity (VA), subjective visual quality (SVQ), and ocular aberrations were evaluated. A new re-evaluation of these parameters was performed after 1 year wearing MAGD CScL. RESULTS: Eighteen eyes of 18 patients (10 male and 8 female) with irregular cornea after LASIK surgery participated in this study; their ages ranged from 27 to 39 years (mean±SD, 32.6±3.8 years). All patients showed good fitting characteristics: optimal values were seen for lens position and lens movement. Statistically significant differences were found between before and after fitting MAGD CScL in the VA (mean±SD, 0.14±0.03 logMAR and 0.01±0.06 logMAR, respectively; P<0.001); ocular aberrations of second-order, coma, spherical; and the total higher-order aberrations (HOAs) (all P<0.001). The total HOAs decreased by approximately 78% to normal levels after fitting MAGD CScL. In addition, SVQ was also significantly improved after fitting MAGD CScL (16 eyes were favorable or very favorable). After 1 year wearing MAGD CScL, no statistically significant differences were found in the total HOAs and VA in regard to the initial fitting. CONCLUSIONS: Corneoscleral contact lens with multiaspheric geometry design is proposed as an effective procedure, providing a good VA and an optimal visual quality on irregular corneas after LASIK surgery in myopic subjects.

A rapid method for measuring intraocular lens power in vitro with a focimeter.

In this paper we describe a new method for measuring the intraocular lens (IOL) power using a focimeter, a negative ophthalmic lens and a saline solution (0.9% NaCl). To test this we measured the power of 58 different IOLs and we compared them with the power stated by the manufacturer. Despite the limitations, the results show a good correlation.

Image quality comparison of two multifocal IOLs: influence of the pupil.

PURPOSE: To evaluate the effect of pupil size on image quality of a sectorial multifocal intraocular lens (IOL), the Lentis Mplus (Oculentis GmbH, Berlin, Germany), and the Acri.LISA IOL (Carl Zeiss Meditec, Jena, Germany). METHODS: The authors measured the MTFs of the Lentis Mplus LS-312 IOL and the Acri.LISA 366D IOL with three different sizes of pupil diameters: 3, 4, and 5 mm. The MTF was calculated from the cross-line spread function recorded with the OPAL Vector System (Image Science Ltd., Oxford, UK) by using fast Fourier-transform techniques. RESULTS: In distance focus, the image quality provided by the Lentis Mplus IOL was better than that of the Acri. LISA IOL with all pupil diameters. In near focus, the MTF of the Acri.LISA IOL was better with a 3-mm pupil, but poor with larger pupils. The aberration effect was equal in both IOLs in distance focus, but in near focus and with a 3-mm pupil, the Acri.LISA IOL was less affected by the aberration than the Lentis Mplus IOL. CONCLUSION: The Lentis Mplus IOL provides better distance image quality than the Acri.LISA IOL, whereas the near image quality of the Acri.LISA IOL is better with small-pupil diameter. The sectorial design makes this IOL more suitable for patients with a pupil diameter greater than 3 mm.

Subfoveal and Parafoveal Choroidal Thickening in Patients with Keratoconus Using the ETDRS Grid on Swept-Source OCT.

INTRODUCTION: There is growing evidence that confirms morphological changes in the posterior structures in patients with keratoconus (KC); however, isolated alterations could have been missed. This study assesses choroidal thickness (CT) in the fovea and beyond in KC eyes. METHODS: This prospective case-control and non-randomized study enrolled 107 eyes, 62 eyes of 62 patients with KC, and 45 age-matched eyes of 45 control subjects with axial length in the range of 22-26 mm. Swept-source optical coherence tomography (SS-OCT) was performed to manually measure the subfoveal choroidal thickness (SCT) using a single-line scan. CT was obtained automatically from the Early Treatment Diabetic Retinopathy Study (ETDRS) grid using the 12-lines radial scan pattern. A two-way repeated-measures analysis of variance (ANOVA) was conducted to evaluate CT variations among macular eccentricity, parafoveal area, and the interaction between both factors. CT was compared in all parafoveal areas between groups and subgroups of KC. RESULTS: SCT was significantly thicker in KC eyes (357 ± 57 µm) than in healthy eyes (325 ± 63 µm) (p < 0.001). Significant choroidal thickening was observed in the central ring and outer and inner rings of the temporal, superior, and inferior parafoveal macular areas (p < 0.001), except in the outer ring of the nasal macular zone (p > 0.05) of KC compared to healthy eyes. The CT significantly decreased from the center to the outer ring regardless of the presence of KC (p < 0.001). The choroid in the nasal macular zone was significantly thinner than that in the temporal, superior, and inferior parafoveal areas (p < 0.001). CONCLUSIONS: The choroidal structure increased its thickness not only in the subfoveal area, but also in eight parafoveal areas of the ETDRS grid encompassing a wider area of macular examination. These findings demonstrate and corroborate that keratoconus is not a purely corneal disease. Furthermore, it confirms the role that the choroidal structure has in the pathophysiology of keratoconus.

The Role of OCT in Follow-Up of Fungal Keratitis Caused by Beauveria bassiana in Contact Lens Wearer.

A 25-year-old Caucasic female was referred to our clinic after suffering from infectious keratitis in the right eye for a month. The patient was a contact lens user and had no history of ocular trauma. Furthermore, the patient did not report any relevant antecedent. The main complaint was intense photophobia and pain. Infectious keratitis remains one of the main complications of contact lens wear and can become a therapeutic challenge in some patients. Although the most frequent causal agent is bacterial, other causes such as herpes virus, Acanthamoeba or fungi should be considered when antimicrobial therapy does not work as expected clinically. Fungal keratitis normally appears on previously damaged corneas, but it can also develop in contact lens wearers. Beauveria bassiana is an unusual pathogen which has been diagnosed more frequently lately per the clinical reports in the last 30 years, so it can be included in the diagnostic scheme when a fungal keratitis is suspected. In clinical management, AS-OCT may be a functional tool to assess the evolution and monitor the response to microbial agents and surgery. Although more studies are needed, some characteristic features have been described and can help to diagnose a fungal keratitis against other infections. AS-OCT can also play an important role in monitoring the corneal scarring after the keratitis episode, and it may be useful to plan post-infection therapy for visual rehabilitation.

Study of stereopsis using a depth sensation detection platform equipped with computer vision technology (DALE3D).

BACKGROUND AND OBJECTIVES: The invention described herein is a prototype based on computer vision technology that measures depth perception and is intended for the early examination of stereopsis. MATERIALS AND METHODS: The prototype (software and hardware) is a depth perception measurement system that consists on: (a) a screen showing stereoscopic models with a guide point that the subject must point to; (b) a camera capturing the distance between the screen and the subject's finger; and (c) a unit for recording, processing and storing the captured measurements. For test validation, the reproducibility and reliability of the platform were calculated by comparing results with standard stereoscopic tests. A demographic study of depth perception by subgroup analysis is shown. Subjective comparison of the different tests was carried out by means of a satisfaction survey. RESULTS: We included 94 subjects, 25 children and 69 adults, with a mean age of 34.2 ± 18.9 years; 36.2 % were men and 63.8 % were women. The DALE3D platform obtained good repeatability with an interclass correlation coefficient (ICC) between 0.94 and 0.87, and coefficient of variation (CV) between 0.1 and 0.26. Threshold determining optimal and suboptimal results was calculated for Randot and DALE3D test. Spearman's correlation coefficient, between thresholds was not statistically significant (p value > 0.05). The test was considered more visually appealing and easier to use by the participants (90 % maximum score). CONCLUSIONS: The DALE3D platform is a potentially useful tool for measuring depth perception with optimal reproducibility rates. Its innovative design makes it a more intuitive tool for children than current stereoscopic tests. Nevertheless, further studies will be needed to assess whether the depth perception measured by the DALE3D platform is a sufficiently reliable parameter to assess stereopsis.

Untargeted analysis and tentative identification of unknown substances in human tears by ultra-high performance liquid chromatography-high resolution mass spectrometry: Pilot study.

In this work, a new approach for the identification of unknown compounds in human tears has been developed and validated using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) linked to an intelligent data acquisition mode (AcquireX DS-dd-MS2) coupled to an automated data processing software (Compound Discoverer™ 3.2). As a pilot research study, four human tear samples from volunteers were analyzed. Data were acquired in both positive and negative ionization modes and exact mass, isotope pattern, and MS2 spectra match were used for the tentative identification. Following this approach, 58 substances were identified, 47 in positive mode and 11 in negative mode, with an estimated concentration ranging from 0.1 to 9000 ng mL-1. Most of them were amino acids, hormones, metabolites, and pharmaceuticals. In order to validate the proposed method, the system suitability was evaluated and 29 commercial analytical standards of the tentatively identified substances were analyzed, of which 28 were confirmed obtaining a high identification accuracy (96.6 %). These results confirm that the screening tool presented in this work can facilitate the discovery of new metabolites, novel potential biomarkers, and substances to which the person is exposed, such as pollutants.

Anterior Scleral Thickness Profile in Keratoconus.

PURPOSE: Considering that peripheral corneal thinning occurs in keratoconus (KC), the anterior scleral thickness (AST) profile was measured to compare thickness variations in healthy and KC eyes across several meridians. METHODS: This cross-sectional case-control study comprised 111 eyes of 111 patients: 61 KC eyes and 50 age- and axial-length-matched healthy eyes. The AST was explored at three scleral eccentricities (1, 2, and 3 mm from the scleral spur) across four scleral zones (nasal, temporal, superior, and inferior) by using swept-source optical coherence tomography. The AST variations among eccentricities and scleral regions within and between groups were investigated. RESULTS: The AST significantly varied with scleral eccentricity in healthy eyes over the temporal meridian (p = 0.009), whereas in KC eyes, this variation was observed over the nasal (p = 0.001), temporal (p = 0.029) and inferior (p = 0.006) meridians. The thinnest point in both groups was 2 mm posterior to the scleral spur (p < 0.001). The sclera was thickest over the inferior region (control 581 ± 52 µm, KC 577 ± 67 µm) and thinnest over the superior region (control 448 ± 48 µm, KC 468 ± 58 µm) in both populations (p < 0.001 for all eccentricities). The AST profiles were not significantly different between groups (p > 0.05). The inferior-superior thickness asymmetry was statistically different 2 mm posterior to the scleral spur between groups (p = 0.009), specifically with subclinical KC (p = 0.03). There is a trend where the asymmetry increases, although not significantly, with the KC degree (p > 0.05). CONCLUSIONS: KC eyes presented significant thickness variations among eccentricities over the paracentral sclera. Although AST profiles did not differ between groups, the inferior-superior asymmetry differences demonstrated scleral changes over the vertical meridian in KC that need further investigation.

Improving Visual Comfort during Computer Gaming with Preservative-Free Hyaluronic Acid Artificial Tears Added to Ergophthalmological Measures.

Digital asthenopia (DA) or Computer Vision Syndrome can occur after prolonged use of digital devices and is usually managed with ergophthalmological measures and the use of artificial tears. This prospective, controlled study evaluated the use of hyaluronic acid artificial tears on the signs and symptoms of DA in participants of a videogame convention. Subjects (n = 56) were randomized into a control group (CG, n = 26), which followed ergophthalmological measures, and a study group (SG, n = 30), which followed ergophthalmological measures and instilled 1 drop of artificial tears with hyaluronic acid 0.15% four times a day. Subjects were evaluated before and after playing for three consecutive days for eye dryness (SPEED questionnaire), conjunctival hyperemia, corneal fluorescein staining, conjunctival lissamine green staining, tear breakup time, Schirmer I test, near convergence and accommodation, and using questionnaires for DA symptoms. After 3 days of intense videogaming, the SPEED score of CG increased significantly (p = 0.0320), while for the SG it was unchanged. Similarly, the CG presented significant increases in ocular fatigue (p = 0.0173) and dryness (p = 0.0463), while these parameters decreased significantly in the SG (p = 0.0149 and p = 0.00427, respectively). This study confirms the protective effect of hyaluronic acid artificial tears against DA symptoms associated with prolonged visual display terminal use.