Additional Applications of Corneal Cross Linking

Corneal collagen cross-linking (CxL) is a prevalent surgical method for the management of keratoconus. However, literature suggests that, further to keratoconus, CxL has a beneficial impact on a series of corneal related diseases and states

Impact of intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell and nerve fibre layer thickness in Neovascular age-related macular degeneration

Purpose: To compare the effects of monotherapy with intravitreal ranibizumab, aflibercept and bevacizumab on retinal ganglion cell layer (RGCL) and retinal nerve fibre layer (RNFL) in patients with naïve neovascular age-related macular degeneration (nAMD). Methods: This is a retrospective cohort study with three-groups comparison. 83 patients and 97 eyes on continuous monotherapy with an intravitreal anti-vascular endothelial growth factor (anti-VEGF) were followed for 24months and divided into three groups according to anti-VEGF (aflibercept: 25 eyes, ranibizumab: 34 eyes, bevacizumab: 38 eyes). Main outcome measures included: RGCL and RNFL thickness, best corrected visual acuity (BCVA), central macular thickness (CMT), macular volume (MV) and the presence of intraretinal fluids (IRF), subretinal fluids (SRF) and retinal pigment epithelial atrophy (RPE-atrophy). All outcome measures were recorded at the time of the first injection, 1 and 2years after treatment and compared longitudinally and between groups. Results: The mean age was 79±7years. The RGCL thickness, MV, CMT and the presence of IRF and SRF decreased significantly within all three medication groups (p<0.05 for all) with no significant difference between groups over the 2-year follow-up period (p>0.10 for all). The decrease in RNFL thickness was not significant within or between the groups after a 2-year follow-up (p>0.055 for all). RPE-atrophy increased significantly after 2 years in all three groups (p<0.028 for all) with no significant difference between groups at all three time points (p>0.307 for all). BCVA was comparable between the three groups over the 2-year follow-up period (p>0.22 for all). Conclusions: Monotherapy with intravitreal aflibercept, bevacizumab and ranibizumab was associated with comparable significant decreases in RGCL thickness, CMT, MV, IRF and SRF in naïve nAMD patients during the first 2 years of treatment. Furthermore, no significant differences either in BCVA or RNFL thickness were observed between the three intravitreal anti-VEFGs during the first 2 years of treatment

Φασματοσκοπική μελέτη οφθαλμικών παθήσεων και ανίχνευση μορίων φαρμάκων

Laser Raman spectroscopy is an inelastic light scattering technique able to characterize molecules in aqueous environments. The purpose of this work is to develop a non-contact and non-invasive spectroscopic method to identify and eventually quantify the presence of medicines (e.g. antibiotics) and physiological substances (e.g. glucose) in the aqueous humor of the eye. Α new laser light delivery probe has been developed and adapted to a Raman spectroscopic system with the ability of favorable collection of the Raman light at 90o scattering geometry while scanning the anterior chamber of the eye. The technique is applied both, to porcine eyes in-vitro, max. 24 hours after death and extraction, for ceftazidime, amphotericin B and glucose and to a commercially available artificial anterior chamber (AAC) fitted with corneas of porcine eyes for ceftazidime, amphotericin B, amikacin sulphate and ciprofloxacin. Finally, a PLS chemometric algorithm has been developed to predict the concentration of antibiotics in AAC. This special illumination design gives the opportunity of reducing the direct exposure of the basic cordial ocular tissues, like lens and retina, to the laser beam, while at the same time an optimum collection of scattered light is accomplished. Concentrations close to the minimum inhibitory concentration (MIC) have been detected for antibiotics both in porcine eyes and AAC; the detection of glucose has been realized at concentrations close to the early pathological levels of patients with diabetes. Furthermore, the quantification of concentration of antibiotics in AAC is accomplished by a partial least-squares (PLS) chemometric regression algorithm and the RMS error of the validation procedure further emphasize the promising prospect of the application of the Raman spectroscopy to the Ophthalmology.Η φασματοσκοπία Raman είναι τεχνική ανελαστικής σκέδασης φωτός, ικανή να ανιχνεύει και να χαρακτηρίζει μόρια σε ποικιλία υδατικών διαλυμάτων. Σκοπός της εργασίας είναι η ανάπτυξη μιας μη επεμβατικής, μη καταστροφικής φασματοσκοπικής μεθόδου για την ανίχνευση και τον ποσοτικό προσδιορισμό τόσο φαρμακευτικών ουσιών (π.χ αντιβιοτικών) όσο και φυσιολογικών ουσιών (π.χ γλυκόζη) στο υδατοειδές υγρό οφθαλμού. Στο πλαίσιο της παρούσας εργασίας αναπτύχθηκε μια νέα γεωμετρική οπτική διάταξη για την καθοδήγηση της δέσμης του laser στον οφθαλμό, που προσαρμόζεται σε φασματοσκόπιο Raman με ανιχνευτή CCD, δίνει τη δυνατότητα επιλεκτικής συλλογής του σκεδαζόμενου φωτός, σαρώνοντας τον εμπρόσθιο θάλαμο, σε γεωμετρία σκέδασης 90ο. Τα πειράματα πραγματοποιήθηκαν (α) σε χοιρινούς οφθαλμούς in-vitro, max 24 ώρες μετά τη θανάτωση των ζώων και την αφαίρεση του βολβού, μετά την έγχυση στον εμπρόσθιο θάλαμο μορίων κεφταζιδίμης, αμφοτερισίνης Β και γλυκόζης και (β) σε μοντέλο πρόσθιου θαλάμου (AAC) σε συνδυασμό με κερατοειδή χιτώνα χοιρινών οφθαλμών μετά την έγχυση μορίων κεφταζιδίμης, αμφοτερισίνης, θειικής αμικασίνης και σιπροφλοξασίνης. Επιπλέον, χρησιμοποιήθηκε χημειομετρικός αλγόριθμος μερικών ελαχίστων τετραγώνων (PLS) για να προβλέψει τη συγκέντρωση των αντιβιοτικών στο μοντέλο του πρόσθιου θαλάμου. Με τον νεό αυτό σχεδιασμό αποφεύγεται η απευθείας έκθεση βασικών οφθαλμικών ιστών, όπως του φακού και του αμφιβληστροειδούς, στη δέσμη του laser, ενώ παράλληλα επιτυγχάνονται βέλτιστες συνθήκες συλλογής του σκεδαζόμενου φωτός βελτιώνοντας το λόγο σήματος/θορύβου των φασμάτων. Ανιχνεύτηκαν συγκεντρώσεις στην περιοχή της μέσης ανασταλτικής πυκνότητας για τα αντιβιοτικά τόσο στο υδατοειδές υγρό χοιρινών οφθαλμών όσο και στο μοντέλο του πρόσθιου θαλάμου? η γλυκόζη ανιχνεύτηκε σε συγκέντρωση κοντά στα παθολογικά επίπεδα των διαβητικών ασθενών. Με βάση και το σφάλμα RMS της ποσοτικής ανάλυσης PLS, προσδοκάται βάσιμα ότι η μέθοδος είναι δυνατό χρησιμοποιηθεί στον τομέα της οφθαλμολογίας για τη μελέτη της φαρμακοκινητικής καθώς και για την έγκαιρη διάγνωση ασθενειών (π.χ. σακχαρώδης διαβήτης)

Efficacy of the travoprost/timolol fixed combination versus the concomitant use of travoprost 0.004% and timolol 0.1% gel formulation

Vassilios Kozobolis,1,2 Aristeidis Konstantinidis,1,2 Haris Sideroudi,2 Miguel Teus3 1Department of Ophthalmology, Democritus University of Thrace, Alexandroupolis, Greece; 2Eye Institute of Thrace (EIT), Democritus University of Thrace, Alexandroupolis, Greece; 3University of Alcala, Madrid, Spain Purpose: To compare the hypotensive effect of travoprost 0.004%/timolol 0.5% fixed combination (TTFC) to the concomitant use of travoprost and timolol 0.1% gel formulation (Trav + Geltim). Materials and methods: Thirty-three patients (62 eyes) were enrolled and divided into two groups. Patients in group 1 (31 eyes) received the TTFC and patients in group 2 (31 eyes) received the concomitant treatment with Trav + Geltim. Patients on previous antiglaucoma treatment discontinued their drops for 2&ndash;4 weeks before starting their new treatment (TTFC or Trav + Geltim). The drops were instilled in the evening in group 1 and in group 2, the prostaglandin was installed in the evening, and timolol in the morning. IOP was measured at 1 and 3 months after the initiation of treatment at four time points during the day (09:00, 12:00, 15:00, and 18:00). Results: Both groups showed significant IOP reduction from baseline at all time points at 1 and 3 months. When the two groups were compared, group 2 showed slightly better hypotensive effect that reached statistical significance only at the 18:00 time point at both 1 and 3 months. Conclusion: Both the TTFC and the concomitant use of the travoprost/timolol gel showed similar hypotensive effect with the latter being slightly more potent in reducing the IOP. Keywords: prostaglandin, timolol gel, glaucoma, fixed combinatio

Impact of polyethylene glycol 400/propylene glycol/hydroxypropyl-guar and 0.1% sodium hyaluronate on postoperative discomfort following cataract extraction surgery: a comparative study

Abstract Background Universal postoperative guidelines for cataract extraction surgery are yet to be introduced. Artificial tears are gaining popularity as an additional integral component of the postoperative regime. The primary objective of this study was to explore the impact of two prevalent artificial tear preparations on postoperative discomfort following cataract extraction surgery. Methods A total of 180 patients that underwent cataract extraction surgery were randomly divided into three groups according to their postoperative regime: a) Study group 1 (SG1) received a fixed combination of tobramycin and dexamethasone (FCTD) quid for 3 weeks and, additionally polyethylene glycol 400/propylene glycol/hydroxypropyl-guar quid, for 6 weeks, b) Study group 2 (SG2) received FCTD quid for 3 weeks and, additionally 0.1% sodium hyaluronate provided in the COMOD® device quid, for 6 weeks, and, c) Control Group (CG) received only FCTD quid for 3 weeks. The following indexes were evaluated at three postoperative checkpoints: 1) Subjective discomfort index (SDI) derived from four direct 10-scale Likert-type questions that were addressed to the patient and pertained to: a) foreign body sensation (FBS), b) blinking discomfort (BD), c) stinging sensation (SS), d) tearing sensation (TS), 2) Tear break-up time (TBUT), 3) Central corneal thickness (CCT) and, 4) Central Corneal Sensitivity (CCS). Results Both groups showed increased CCT values at the first examination point and reduced CCS values at all examination points. Furthermore, both SGs had better TBUT times at all examination points compared to CG (CG: 8.86 ± 1.08, SG1: 9.59 ± 1.45, CG2: 9.45 ± 1.33, p < 0.05). BD was significantly better in both SGs only at the 1st week of examination, while SDI values were better until the 3rd week and only borderline better at 6th week. Lastly, no significant differences were detected between SGs, regarding all parameters, at all examination points. Conclusion Polyethylene glycol 400/propylene glycol/hydroxypropyl-guar and 0.1% sodium hyaluronate provided in the COMOD® device seem to be equally efficient in alleviating OSD symptoms following cataract extraction surgery and any of them should be routinely added to the postoperative regime. Trial registration ClinicalTrials.gov Identifier: https://clinicaltrials.gov/ct2/show/NCT02558218 NCT0255821

The Effect of Corneal Refractive Surgery on Glaucoma

Laser-assisted refractive procedures have become very popular in the last two decades. As a result, a “generation” of patients with altered corneal properties is emerging. These patients will require both cataract extraction and glaucoma follow-up in the future. Since the glaucoma examination largely depends on the corneal properties, the reshaped postrefractive surgery cornea poses a challenge in the diagnosis, follow-up, and management of the glaucomatous patient. In order to overcome this problem, every patient who is planned to undergo corneal refractive surgery must have a thorough glaucoma examination in order for the ophthalmologist to be able to monitor their patients for possible glaucoma development and/or progression. Some examinations such as tonometry are largely affected by the corneal properties, while others such as the evaluation of the structures of the posterior pole remain unaffected. However, the new imaging modalities of the anterior segment in combination with the most recent advances in tonometry can accurately assess the risk for glaucoma and the need for treatment

Impact of corneal cross-linking combined with photorefractive keratectomy on blurring strength

Georgios Labiris,1,2 Haris Sideroudi,2 Dimitris Angelonias,2 Kimonas Georgantzoglou,2 Vassilios P Kozobolis1,21Department of Ophthalmology, University Hospital of Alexandroupolis, 2Eye Institute of Thrace, Alexandroupolis, GreecePurpose: The aim of this study was to evaluate the impact of corneal cross-linking combined with photorefractive keratectomy (PRK) on blurring strength.Methods: A total of 63 patients with keratoconus were recruited for this study, and two study groups were formed according to the therapeutic intervention: corneal collagen cross-linking (CxL) group (33 patients) received corneal cross-linking according to the Dresden protocol, while the rest additionally received topography-guided photorefractive keratectomy (tCxL). The impact of surgical procedure on blurring strength was assessed by power vector analysis. Potential association between blurring strength and vision-specific quality of life was assessed using the National Eye Institute Visual Function Questionnaire (NEI-VFQ) 25 instrument.Results: Blurring strength presented excellent correlation with NEI-VFQ scores both preoperatively and postoperatively (all P&lt;0.01). Both groups demonstrated nonsignificant changes in best-corrected visual acuity; however, only the tCxL group had significant reduction in blurring strength (13.48+10.86 [preoperative], 4.26+7.99 [postoperative], P=0.042).Conclusion: Only the combined treatment (tCxL) resulted in significant reduction in blurring strength. Moreover, the excellent correlation of blurring strength with NEI-VFQ scores indicates its reliability as an index of self-reported quality of life in keratoconus, since it seems to address the nonsignificant changes in best-corrected visual acuity following CxL treatments that are conceived as subjective improvement by the patient.Keywords: keratoconus, cornea crosslinking, blurring strength, tCx