Comparison of Intraocular Pressure before and after Laser In Situ Keratomileusis Refractive Surgery Measured with Perkins Tonometry, Noncontact Tonometry, and Transpalpebral Tonometry

Purpose. To compare the intraocular pressure (IOP) before and after Laser In Situ Keratomileusis (LASIK), measured by Diaton, Perkins, and noncontact air pulse tonometers. Methods. Fifty-seven patients with a mean age of 34.88 were scheduled for myopia LASIK treatment. Spherical equivalent refraction (SER), corneal curvature (K), and central corneal thickness (CCT) and superior corneal thickness (SCT) were obtained before and after LASIK surgery. IOP values before and after surgery were measured using Diaton, Perkins, and noncontact air pulse tonometers. Results. The IOP values before and after LASIK surgery using Perkins tonometer and air tonometers were statistically significant (). However, no significant differences were found () for IOP values measured with Diaton tonometer. CCT decreases significantly after surgery () but no statistical differences were found in SCT (). Correlations between pre- and postsurgery were found for all tonometers used, with and for the air pulse tonometer, and for Perkins, and and for Diaton. Conclusion. Transpalpebral tonometry may be useful for measuring postsurgery IOP after myopic LASIK ablation because this technique is not influenced by the treatment.

The Use of Mucoadhesive Polymers to Enhance the Hypotensive Effect of a Melatonin Analogue, 5-MCA-NAT, in Rabbit Eyes

Purpose.: 5-Methoxy-carbonylamino-N-acetyltryptamine (5-MCA-NAT, a melatonin receptor agonist) produces a clear intraocular pressure (IOP) reduction in New Zealand White rabbits and glaucomatous monkeys. The goal of this study was to evaluate whether the hypotensive effect of 5-MCA-NAT was enhanced by the presence of cellulose derivatives, some of them with bioadhesive properties, as well as to determine whether these formulations were well tolerated by the ocular surface. Methods.: Formulations were prepared with propylene glycol (0.275%), carboxymethyl cellulose (CMC, 0.5% and 1.0%) of low and medium viscosity and hydroxypropylmethyl cellulose (0.3%). Quantification of 5-MCA-NAT (100 μM) was assessed by HPLC. In vitro tolerance was evaluated by the MTT method in human corneal-limbal epithelial cells and normal human conjunctival cells. In vivo tolerance was analyzed by biomicroscopy and specular microscopy in rabbit eyes. The ocular hypotensive effect was evaluated measuring IOP for 8 hours in rabbit eyes. Results.: All the formulations demonstrated good in vitro and in vivo tolerance. 5-MCA-NAT in CMC medium viscosity 0.5% was the most effective at reducing IOP (maximum IOP reduction, 30.27%), and its effect lasted approximately 7 hours. Conclusions.: The hypotensive effect of 5-MCA-NAT was increased by using bioadhesive polymers in formulations that are suitable for the ocular surface and also protective of the eye in long-term therapies. The use of 5-MCA-NAT combined with bioadhesive polymers is a good strategy in the treatment of ocular hypertension and glaucoma.

Increased Levels of Diadenosine Polyphosphates in Dry Eye

Purpose. To analyze the levels of the diadenosine polyphosphates Ap4A and Ap5A in tears, in a set of control subjects and in groups of symptomatic and nonsymptomatic persons with dry eye. Methods. Ninety-seven subjects participated in the study. The subjects were divided into five experimental groups: control subjects; symptomatic patients with normal tear secretion; symptomatic patients with low tear secretion; forced blink; and corneal mechanical stimulation provided by a gas esthesiometer. The Schirmer I test was used to measure and collect tear secretions from each subject. All samples were processed by high pressure liquid chromatography (HPLC) and their Ap4A and Ap5A levels determined. Results. The levels of Ap4A and Ap5A in tears were greater in all symptomatic patients than in control subjects, especially in symptomatic subjects with low tear secretion. Within the symptomatic subjects with normal tear secretion, significant differences in concentrations of Ap4A and Ap5A were found between men and women. In the forced blink experiments, concentrations of the Ap4A and Ap5A rose with increasing blink frequency. When the cornea was mechanically stimulated, the levels of Ap4A and Ap5A rose significantly during both moderate and high-flow rate tests. Conclusions. The increased levels of Ap4A and Ap5A in tears of patients with dry eye allow these dinucleotides to be used as objective biomarkers in dry eye conditions.

Changes in Diadenosine Polyphosphates during Alignment-Fit and Orthokeratology Rigid Gas Permeable

Purpose.: To evaluate the levels of dinucleotides diadenosine tetraphosphate (Ap4A) and diadenosine pentaphosphate (Ap5A) in tears of patients wearing rigid gas permeable (RGP) contact lenses on a daily wear basis and of patients wearing reverse-geometry RGP lenses overnight for orthokeratology treatment. Methods.: Twenty-two young volunteers (10 females, 12 males; 23.47 ± 4.49 years) were fitted with an alignment-fit RGP lens (paflufocon B) for a month, and after a 15-day washout period they were fitted with reverse-geometry RGP lenses for corneal reshaping (paflufocon D) for another month. During each period, tears were collected at baseline day 1, 7, 15, and 28. Ap4A and Ap5A were measured by high-pressure liquid chromatography (HPLC). Additionally, corneal staining, break-up time (BUT), Schirmer test, and dryness symptoms were evaluated. Results.: Ap4A concentrations increased significantly from baseline during the whole period of daily wear of RGP lenses (P < 0.001); concentration was also significantly higher than in the orthokeratology group, which remained at baseline levels during the study period except at day 1 (P < 0.001) and day 28 (P = 0.041). While BUT and Schirmer remained unchanged in both groups, discomfort and dryness were significantly increased during alignment-fit RGP daily wear but not during the orthokeratology period. Conclusions.: Daily wear of RGP lenses increased the levels of Ap4A due to mechanical stimulation by blinking of the corneal epithelium, and this is associated with discomfort. Also, orthokeratology did not produce symptoms or signs of ocular dryness, which could be a potential advantage over soft contact lenses in terms of contact lens-induced dryness.

Memorias seminario internacional de investigación e innovación en ciencias de la visión : temática lentes de contacto y superficie ocular

Tesis (Optometra). -- Universidad de La Salle, Facultad de Ciencias de La Salud. Programa de Optometria, 2014

Fonctionnalité in vivo d’un endothélium cornéen reconstitué par injection de cellules endothéliales cornéennes dans la chambre antérieure d’un modèle félin

Introduction : Malgré leur état non-prolifératif in vivo, les cellules endothéliales cornéennes (CEC) peuvent être amplifiées in vitro. Leur transplantation subséquente par injection intracamérale pourrait surmonter la pénurie de tissus associée à l’allo-greffe traditionnelle – l’unique traitement définitif disponible pour les endothéliopathies cornéennes. Objectif : Évaluer la fonctionnalité d’un endothélium cornéen reconstitué par injection de CEC dans la chambre antérieure du félin. Méthodes : Les yeux droits de 16 animaux ont été opérés. Huit ont été désendothélialisés centralement avec injection de 2x10e5 (n=4) ou 1x10e6 (n=4) CEC félines supplémentées avec Y-27632 et marquées avec SP-DiOC18(3). Deux ont été désendothélialisés complètement et injectés avec 1x10e6 CEC et Y-27632. Six contrôles ont été désendothélialisés centralement (n=3) ou complètement (n=3) et injectés avec Y-27632 sans CEC. La performance clinique, l’intégrité anatomique, le phénotype fonctionnel et l’expression de SP-DiOC18(3) du nouvel endothélium ont été étudiés. Résultats : Les cornées greffées avec 2x10e5 CEC et les contrôles désendothélialisés centralement ont réussi le mieux cliniquement. Les contrôles désendothélialisés complètement sont restés opaques. L’histopathologie a révélé une monocouche endothéliale fonctionnelle dans les cornées greffées avec 2x10e5 CEC et les contrôles désendothélialisés centralement, une multicouche endothéliale non-fonctionnelle dans les cornées désendothélialisées centralement et greffées avec 1x10e6 CEC, et un endothélium fibrotique non-fonctionnel dans les cornées désendothélialisées complètement. L’expression de SP-DiOC18(3) était rare dans les greffes. Conclusion : La thérapie par injection cellulaire a reconstitué un endothélium partiellement fonctionnel, auquel les CEC injectées n’ont contribué que peu. L’injection de Y-27632 sans CEC a reconstitué l’endothélium le plus sain. Des études additionnelles investiguant l’effet thérapeutique de Y-27632 seul sont justifiées.

International flavours

It is an Olympic year and we have just witnessed the fantastic games hosted by Rio de Janeiro. Well done to team USA for winning the most medals overall but also well done to so many other nations and individuals who performed so well or were ambassadors in other ways. Teenage swimmer Yusra Mardini who swam for the refugee team and South Africa's Wayde van Niekerk who broke the longstanding 400 m record of Michael Johnson that has stood since 1999. Of course, we must mention sprinter Usain Bolt and swimmer Michael Phelps, who have now transcended superstar status and entered a new level of icon. My personal highlight was the sportsmanship witnessed in the 5000 m when American Abbey D’Agostino was accidentally felled by New Zealand runner Nikki Hamblin. D’Agostino helped Hamblin back to her feet but slumped to the track after realising her own injury. Hamblin helped her up and stayed with her so that both completed the race. The International Olympic Committee has awarded both with the prestigious Pierre de Coubertin award, also known as the International Fair Play Trophy. Fair play is of paramount importance in publishing in peer-reviewed papers. At CLAE we try and maintain, as do other journals, this by ensuring double blind peer review and allowing authors to select the most appropriate handling editor for their submission. Our handling editors are placed across the world (2 in Europe, 1 in the Americas, 1 in Australia and 1 in Asia) and part of their role is to encourage submissions from their region. Over the last decade we certainly have seen more and more papers from places that haven’t previously published in CLAE. In this issue of CLAE we have a true international blend of papers. We have papers from authors from the UK, USA, Iran, Jordan, France, Poland, Turkey, Nigeria, France, Spain and Brazil. I think it's a testament to the continued success of the journal that we are attracting new writers from so many parts of the world and retain papers from more established authors and research centres. We do continue to attract many weaker papers that are rejected early in the review process. Often these will be unexceptional case reports or papers describing a surgical technique. Case reports are published but only those that offer something original and especially those with interesting photographs. In this issue you will see Professor James Wolffsohn (UK) has an interesting paper around a lot of the focus of his recent research activity into clinical evaluation of methods of correcting presbyopia. In this paper he highlights predictors to aid success of presbyopic contact lenses. If you have been involved in any clinical work or research in the field of dry eye disease then you will know well the CLDEQ (Contact Lens Dry Eye Questionnaire) devised by Robin Chalmers and her colleagues (USA). This issue of CLAE details the latest research using the CLDEQ-8 (the 8 item version of the CLDEQ). The Shahroud Eye Cohort Study has produced many papers already and in this issue we see Fotouhi Akbar (Iran) looking at changes in central and peripheral corneal thickness over a five year period. These days we use a lot of new instrumentation, such as optical low-coherence reflectometry. In this issue Emre Güler (Turkey) compares that to a new optical biometry unit. Dry eye is more common and in this issue we see a study by Oluyemi Fasina (Nigeria) to investigate the disease in adults in South-West Nigeria. The TearLab™ is now commonly used to investigate osmolarity and Dorota Szczesna-Iskander (Poland) looks at measurement variability of this device. Following the theme of dry eyes and tear testing Renaud Laballe (France) looks at the use of scleral lenses as a reservoir-based ocular therapeutic system. In this issue we have a couple of papers looking at different aspects of keratoconus. Magdalena Popiela (UK) looks at demographics of older keratoconic patients in Wales, Faik Orucoglu (Turkey) reports a novel scoring system for distinguishing keratoconus from normal eyes, Gonzalo Carracedo (Spain) reports the effect of rigid gas permeable lens wear on dry eye in keratoconus and Hatice Nur Colak (Turkey) compares topographic and aberrations in keratoconus. Other interesting papers you will find are Mera Haddad (Jordan) investigates contact lens prescribing in Jordan, Camilla Fraga Amaral (Brazil) offers a report on the use of ocular prosthetics, Naveed Ahmed Khan (Malaysia) reports of the use of dimethyl sulfoxide in contact lens disinfectant and Michael Killpartrick (UK) offers a short piece with some useful advice on contamination risk factors that may occur from the posterior surface of disposable lenses. So for this issue I would say that the Gold Medal for biggest contribution in terms of papers has to go to Turkey. I could have awarded it to the UK too, but Turkey has three full papers and the UK has two plus one short communication. Turkey is also one of the countries that has shown the largest increase in submissions over the last decade. Finally, welcome aboard to our newest Editorial Board Member Nicole Carnt from Australia. Nicole has been an active researcher for many years and acted as a reviewer for CLAE many times in the past. We look forward to working with you.

Long-term efficacy of orthokeratology contact lens wear in controlling the progression of childhood myopia

Purpose: The primary outcome of this study is to compare the axial length growth of white European myopic children wearing orthokeratology contact lenses (OK) to a control group (CT) over a 7-year period. Methods: Subjects 6–12 years of age with myopia −0.75 to −4.00DS and astigmatism ≤1.00DC were prospectively allocated OK or distance single-vision spectacles (SV) correction. Measurements of axial length (Zeiss IOLMaster), corneal topography, and cycloplegic refraction were taken at 6-month intervals over a 2-year period. Subjects were invited to return to the clinic approximately 5 years later (i.e., 7 years after the beginning of the study) for assessment of their ocular refractive and biometric components. The CT consisted of 4 SV and 12 subjects who switched from SV to soft contact lens wear after the initial 2 years of SV lens wear. Changes in axial length relative to baseline over a 7-year period were compared between groups. Results: Fourteen and 16 subjects from the OK and CT groups, respectively, were examined 6.7 ± 0.5 years after the beginning of the study. Statistically significant changes in the axial length were found over time and between groups (both p <0.001), but not for the time*group interaction (p = 0.125). The change in the axial length for the OK group was 22% (p = 0.328), 42% (p = 0.007), 40% (p = 0.020), 41% (p = 0.013), and 33% (p = 0.062) lower than the CT group following 6, 12, 18, 24, and 84 months of lens wear, respectively. Conclusion: A trend toward a reduction in the rate of axial elongation of the order of 33% was found in the OK group in comparison to the CT group following 7 years of lens wear.

Effect of pharmacological pupil dilation on measurements and iol power calculation made using the new swept-source optical coherence tomography-based optical biometer

Purpose: to determine whether pupil dilation affects biometric measurements and intraocular lens (IOL) power calculation made using the new swept-source optical coherence tomography-based optical biometer (IOLMaster 700©; Carl Zeiss Meditec, Jena, Germany). Procedures: eighty-one eyes of 81 patients evaluated for cataract surgery were prospectively examined using the IOLMaster 700© before and after pupil dilation with tropicamide 1%. The measurements made were: axial length (AL), central corneal thickness (CCT), aqueous chamber depth (ACD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW) and pupil diameter (PD). Holladay II and SRK/T formulas were used to calculate IOL power. Agreement between measurement modes (with and without dilation) was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots. Results: mean patient age was 75.17 ± 7.54 years (range: 57–92). Of the variables determined, CCT, ACD, LT and WTW varied significantly according to pupil dilation. Excellent intraobserver correlation was observed between measurements made before and after pupil dilation. Mean IOL power calculation using the Holladay 2 and SRK/T formulas were unmodified by pupil dilation. Conclusions: the use of pupil dilation produces statistical yet not clinically significant differences in some IOLMaster 700© measurements. However, it does not affect mean IOL power calculation.

Fonctionnalité in vivo d’un endothélium cornéen reconstitué par injection de cellules endothéliales cornéennes dans la chambre antérieure d’un modèle félin

Introduction : Malgré leur état non-prolifératif in vivo, les cellules endothéliales cornéennes (CEC) peuvent être amplifiées in vitro. Leur transplantation subséquente par injection intracamérale pourrait surmonter la pénurie de tissus associée à l’allo-greffe traditionnelle – l’unique traitement définitif disponible pour les endothéliopathies cornéennes. Objectif : Évaluer la fonctionnalité d’un endothélium cornéen reconstitué par injection de CEC dans la chambre antérieure du félin. Méthodes : Les yeux droits de 16 animaux ont été opérés. Huit ont été désendothélialisés centralement avec injection de 2x10e5 (n=4) ou 1x10e6 (n=4) CEC félines supplémentées avec Y-27632 et marquées avec SP-DiOC18(3). Deux ont été désendothélialisés complètement et injectés avec 1x10e6 CEC et Y-27632. Six contrôles ont été désendothélialisés centralement (n=3) ou complètement (n=3) et injectés avec Y-27632 sans CEC. La performance clinique, l’intégrité anatomique, le phénotype fonctionnel et l’expression de SP-DiOC18(3) du nouvel endothélium ont été étudiés. Résultats : Les cornées greffées avec 2x10e5 CEC et les contrôles désendothélialisés centralement ont réussi le mieux cliniquement. Les contrôles désendothélialisés complètement sont restés opaques. L’histopathologie a révélé une monocouche endothéliale fonctionnelle dans les cornées greffées avec 2x10e5 CEC et les contrôles désendothélialisés centralement, une multicouche endothéliale non-fonctionnelle dans les cornées désendothélialisées centralement et greffées avec 1x10e6 CEC, et un endothélium fibrotique non-fonctionnel dans les cornées désendothélialisées complètement. L’expression de SP-DiOC18(3) était rare dans les greffes. Conclusion : La thérapie par injection cellulaire a reconstitué un endothélium partiellement fonctionnel, auquel les CEC injectées n’ont contribué que peu. L’injection de Y-27632 sans CEC a reconstitué l’endothélium le plus sain. Des études additionnelles investiguant l’effet thérapeutique de Y-27632 seul sont justifiées.

Agreement and clinical comparison between a new swept-source optical coherence tomography-based optical biometer and an optical low-coherence reflectometry biometer

Purpose To compare measurements taken using a swept-source optical coherence tomography-based optical biometer (IOLmaster 700) and an optical low-coherence reflectometry biometer (Lenstar 900), and to determine the clinical impacts of differences in their measurements on intraocular lens (IOL) power predictions. Methods Eighty eyes of 80 patients scheduled to undergo cataract surgery were examined with both biometers. The measurements made using each device were axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW), and pupil diameter (PD). Holladay 2 and SRK/T formulas were used to calculate IOL power. Differences in measurement between the two biometers were determined using the paired t-test. Agreement was assessed through intraclass correlation coefficients (ICC) and Bland–Altman plots. Results Mean patient age was 76.3±6.8 years (range 59–89). Using the Lenstar, AL and PD could not be measured in 12.5 and 5.25% of eyes, respectively, while IOLMaster 700 took all measurements in all eyes. The variables CCT, AQD, LT, and MK varied significantly between the two biometers. According to ICCs, correlation between measurements made with both devices was excellent except for WTW and PD. Using the SRK/T formula, IOL power prediction based on the data from the two devices were statistically different, but differences were not clinically significant. Conclusions No clinically relevant differences were detected between the biometers in terms of their measurements and IOL power predictions. Using the IOLMaster 700, it was easier to obtain biometric measurements in eyes with less transparent ocular media or longer AL.

Eficacia de la lente de contacto MiSight en la reducción de la progresión de la miopía infantil, no patológica, en edades de 8 a 12 años: ensayo clínico aleatorizado

Tesis inédita presentada en la Universidad Europea de Madrid. Facultad de Ciencias de la Salud. Programa de Doctorado en Ciencias de la Visión