Real and Pseudoaccommodation in Accommodative Lenses

In the attempt to manage presbyopia, different intraocular lens designs have been proposed such as monofocal IOLs with monovision or multifocal IOLs. Even though the lenses mentioned offer satisfactory visual results, contemporary ophthalmology has not completely answered the presbyopic dilemma by simulating the accommodative properties of the crystalline lens itself. Accommodative IOLs were designed to fill this gap and provide satisfactory vision for all distances by restoring some degree of “pseudoaccommodation.” Pseudo accommodative capability can be linked to monofocal IOL's as well but the results are not satisfactory enough to fully support unaided near vision. Pseudoaccommodation is a complex phenomenon that can be attributed to several static (i.e., pupil size, against-the-rule cylindrical refractive error, multifocality of the cornea) and dynamic (i.e., anterior movement of the implant itself) factors. Objective measurement of the accommodative capability offered by the accommodative IOLs is extremely difficult to obtain, and different methods such as autorefractometers, retinoscopy, and ultrasound imaging during accommodative effort, ray tracing, or pharmacological stimulation have been developed but the results are sometimes inconsistent. Despite the difficulties in measuring accommodation, accommodative IOLs represent the future in the attempt to successfully “cure” presbyopia

Possible Poecilogony Due to Discontinuous Multifactorial Inheritance in Some Mediterranean Species of Raphitoma (Mollusca, Conoidea, Raphitomidae)

At least 10 pairs of similar, most probably closely related, species of Raphitoma are often sampled in the same Mediterranean localities. In each pair, one member bears a planktotrophic protoconch and the other a lecithotrophic one. We propose that the phenomenon may be attributed to a simple gene that functions in conjunction with others and environmental factors to exhibit a discontinuous multifactorial inheritance leading to poecilogony. Below a threshold, the animals may produce fewer and larger germ cells, giving rise to fewer and larger eggs and large lecithotrophic embryos with large paucispiral protoconch I, while above that threshold, more and smaller germ cells leading to smaller eggs and to planktotrophic larvae with small protoconch I and large multispiral protoconch II. Preliminary measurements are in support of our hypothesis. Analysis of mitochondrial DNA markers as well as interbreeding experiments could bring an end to the existing confusion

Transepithelial Phototherapeutic Keratectomy Using a 213-nm Solid-State Laser System Followed by Corneal Collagen Cross-Linking with Riboflavin and UVA Irradiation

Purpose. To present a case of a keratoconic patient who underwent epithelial removal with transepithelial phototherapeutic keratectomy (t-PTK) using a 213-nm solid-state laser system followed by corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UVA) irradiation. Methods. Case report. Results. A twenty-four-year-old male with keratoconus underwent CXL treatment after epithelial removal with t-PTK using a solid-state laser system. No intra- or early postoperative complications were found. One month postoperatively, uncorrected visual acuity (UCVA) improved from 20/63 to 20/32 while best spectacle- corrected visual acuity (BSCVA) improved from 20/40 to 20/25. Corneal topography revealed a significant improvement which remained stable during the six-month followup period. Conclusions. Epithelial removal with t-PTK before CXL could improve patient's visual outcome

Clinical Study Long Term Followup of Photorefractive Keratectomy with Adjuvant Use of Mitomycin C

properly cited. Purpose. To study the long term refractive and visual outcomes of photorefractive keratectomy (PRK) with intraoperative application of mitomycin C (MMC). Methods. This study included 37 eyes who received myopic PRK; after photoablation, a sponge soaked in 0.02% MMC solution was applied in all corneas for 2 minutes. Efficacy, safety, predictability, and stability of PRK MMC were evaluated. Endothelial cell density was evaluated at the last postoperative interval. Results. Mean preoperative spherical equivalent (SEQ) was −6.03 ± 1.87 D (diopters) and reduced to −0.09 ± 0.53 D at the last postoperative examination. Mean followup was 44.73 ± 18.24 months. All the eyes were in the ±1.00 D of attempted versus achieved SEQ at the one-year follow-up interval. Furthermore, 95% of the eyes did not lose lines or gained 1 to 2 lines of CDVA, while 5% lost 1 line. At the third postoperative month, 89% of the eyes either were clear or had trace haze, while 4 eyes had mild haze; by the 12-month postoperative interval, none of the eyes demonstrated haze. Mean endothelial cell density (ECD) at the last postoperative interval was 2658 ± 153 cells/mm 2 . Conclusions. PRK, with intraoperative use of MMC, demonstrates stable refractive and visual outcomes up to 44 months after surgery

TFOS European ambassador meeting:Unmet needs and future scientific and clinical solutions for ocular surface diseases

The mission of the Tear Film & Ocular Surface Society (TFOS) is to advance the research, literacy, and educational aspects of the scientific field of the tear film and ocular surface. Fundamental to fulfilling this mission is the TFOS Global Ambassador program. TFOS Ambassadors are dynamic and proactive experts, who help promote TFOS initiatives, such as presenting the conclusions and recommendations of the recent TFOS DEWS II™, throughout the world. They also identify unmet needs, and propose future clinical and scientific solutions, for management of ocular surface diseases in their countries. This meeting report addresses such needs and solutions for 25 European countries, as detailed in the TFOS European Ambassador meeting in Rome, Italy, in September 2019

Corneal collagen crosslinking alone or combined with topography guided photorefractive keratectomy for the treatment of keratoconus: clinical and experimental study

Purpose: To evaluate experimentally and clinically the results of corneal collagen cross-linking (CXL) and of it’s combination with preceding simultaneous topography-guided photorefractive keratectomy (tPRK-CXL) with solid state laser for progressive keratoconus. In the experimental study, we focused on the in-vitro evaluation of the immediate effect of CXL on corneal hydration and stiffness. Clinically, the target of the study was to evaluate the results of CXL and of tPRK-CXL for progressive keratoconus and make comparison between techniques regarding topographic stability, visual acuity, keratometry and in vivo corneal microscopy. Additionally, we focused on the effect of CXL on corneal innervation, corneal sensitivity and tear function in patients with keratoconus. Methods: In the experimental study forty two corneal buttons were divided in two groups; one was irradiated to simulate CXL according to the clinically applied protocol. Subsequently, both groups were brought to osmotic equilibrium with dextran 20% and each button underwent thickness measurement, and measurement of force versus deformation by compression. The hydration (%) of each button was calculated. For the prospective comparative evaluation of CXL and tPRK-CXL thirty eyes received combined tPRK with a solid state laser (maximum ablation depth 50μm) followed by CXL, and 30 eyes received CXL alone. Groups were matched in terms of age and keratoconus stage and corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), keratometry, and corneal confocal microscopy findings were compared. For the evaluation of innervation and tear film we conducted a prospective, interventional case series with twenty four patients with bilateral keratoconus (30 eyes) who underwent CXL. Confocal microscopic analysis of corneal subbasal nerve plexus (total nerve length per image), corneal sensitivity (assessed with the Cochet–Bonnet esthesiometer), basic tear secretion (assessed with Schirmer’s I test with anesthesia) and tear film stability (evaluated by means of tear film break up time [TFBUT]) were assessed preoperatively and at 1, 3, 6, 9, 12, 18 and 24 postoperative month time intervals and pre- to postoperative values were comparedResults: In the experimental study a significant dehydration effect of CXL on corneal buttons after the procedure was demonstrated. In the clinical study of CXL and tPRK-CXL we found that visual acuity and topography of patients in the tPRK-CXL group were significantly better than in the CXL group, without compromising postoperative stability up to three years postoperatively. Effect of CXL as seen in confocal microscopy was deeper in the tPRK-CXL group. No effect was detected on endothelial cells. Regarding effect on innervation and tear film, we found total nerve length per image and corneal sensitivity significantly decreased until the sixth postoperative month. Results of Schirmer’s I test and TFBUT had no statistically significant difference at any time point. Conclusions: Corneal dehydration is detected immediately after the CXL procedure. This phenomenon may contribute to increased mechanical stiffness of the cornea. Simultaneous tPRK followed by CXL in this series of keratoconus patients offered significantly improved vision to treated patients in comparison to CXL alone, and similar good results regarding postoperative stability. A transient decrease in corneal innervation and corneal sensitivity can be observed up to six months after CXL.Σκοπός: Η πειραματική και κλινική αξιολόγηση των αποτελεσμάτων και της μικροσκοπικής εικόνας του κερατοειδούς μετά από επέμβαση διασύνδεσης κερατοειδικού κολλαγόνου με ριβοφλαβίνη και υπεριώδη ακτινοβολία (CXL), καθώς και μετά από τον συνδυασμό της με προηγηθείσα ταυτόχρονη τοπογραφικά καθοδηγούμενη φωτοδιαθλαστική κερατεκτομή με λέιζερ στερεάς κατάστασης (tPRK-CXL). Η αξιολόγηση της ενυδάτωσης, της παχυμετρίας και της συμπιεστότητας του κερατοειδούς με μία πρωτότυπη πειραματική διάταξη μετά από CXL. Επιπρόσθετα, σκοπός ήταν η συγκριτική αξιολόγηση των κλινικών αποτελεσμάτων ανάμεσα στην CXL και την tRK-CXL. Υλικό και μέθοδος: Στο πειραματικό μέρος της μελέτης 42 χοίρειοι κερατοειδείς υπεβλήθησαν στο κλασσικό πρωτόκολλο CXL και υπολογίστηκε η μεταβολή της ενυδάτωσης τους σε συνθήκες ωσμωτικής ισορροπίας με δεξτράνη 20%. Επίσης η συμπιεστότητα τους μετρήθηκε με ειδική πειραματική διάταξη. Στο κλινικό μέρος τα αποτελέσματα ως προς την όραση, την διάθλαση, και την τοπογραφία αξιολογήθηκαν και συγκρίθηκαν ανάμεσα σε ομάδα 30 οφθαλμών που υπεβλήθησαν σε CXL και ομάδα 30 οφθαλμών που υπεβλήθησαν σε tPRK-CXL. Η ποιότητα της δακρυϊκής στιβάδας, η αισθητικότητα του κερατοειδούς και το υποεπιθηλιακό νευρικό πλέγμα του κερατοειδούς αξιολογήθηκαν σε 30 οφθαλμούς που υπεβλήθησαν σε CXL.Αποτελέσματα: Η ενυδάτωση των κερατοειδών μετά την επέμβαση φαίνεται μειωμένη ενώ επίδραση στην συμπιεστότητα δεν μπόρεσε να μετρηθεί. Η όραση και τοπογραφική εικόνα των ασθενών που υπεβλήθησαν στην συνδυασμένη επέμβαση σε σχέση με την ομάδα ελέγχου είναι σημαντικά βελτιωμένες. Η συμπεριφορά των κερατοειδών ως προς τη σταθερότητα και στις δύο ομάδες μετεγχειρητικά ήταν όμοια μέχρι 3 χρόνια μετεγχειρητικά. Μεγαλύτερη διείσδυση της διασύνδεσης φαίνεται εμμέσως από το βάθος το αλλοιώσεων του στρώματος στην συνεστιακή μικροσκοπία στους ασθενείς της ομάδας tPRK-CXL. Οι ποσοτικές παράμετροι αξιολόγησης του υποεπιθηλιακού νευρικού πλέγματος και η αισθητικότητά του κερατοειδούς ήταν σημαντικά μειωμένες μέχρι έξι μήνες μετεγχειρητικά. Η δακρυϊκή στιβάδα δεν φάνηκε να επηρεάζεται. Συμπεράσματα: Η επέμβαση CXL φαίνεται να προκαλεί αφυδάτωση στον κερατοειδή, η οποία πιθανόν να συμμετέχει στην αύξηση της ακαμψίας του. Κλινικά προσφέρει σταθερότητα στους ασθενείς στο διάστημα παρακολούθησης της μελέτης μας, ενώ ο συνδυασμός της με PRK καθοδηγούμενο από την τοπογραφία με το λέιζερ στερεάς κατάστασης έχει πολύ καλά οπτικά αποτελέσματα, φαινομενικά μεγαλύτερη διείσδυση στο βάθος του κερατοειδούς και παρόμοια σταθερότητα με την απλή επέμβαση. Η επέμβαση CXL επηρεάζει προσωρινά την νεύρωση και την αισθητικότητά του κερατοειδούς

ND:YAG laser for preretinal hemorrhage in diabetic retinopathy

Purpose: To present fundus images of a case with severe preretinal hemorrhage in diabetic retinopathy that was treated with posterior hyaloidotomy with an Nd:YAG laser. Observations: A 35-year-old diabetic patient presented with sudden painless loss of vision due to severe preretinal hemorrhage over the macular area and high risk proliferative diabetic retinopathy. Her visual acuity was counting fingers. Posterior hyaloid face was treated with Nd:YAG laser (posterior hyaloidotomy). Panretinal laser photocoagulation was first performed to control the proliferative diabetic retinopathy. Blood drained inferiorly into the vitreous cavity with clearance of the premacular area. Conclusions and importance: Prompt treatment with Panretinal laser photocoagulation followed by posterior hyaloidotomy with the YAG laser is a viable option in order to avoid further proliferative diabetic retinopathy complications and vision loss. The current image clearly depicts treatment efficacy. Keywords: Diabetic retinopathy, Preretinal hemorrhage, YAG laser, Panretinal photocoagulatio

The family Raphitomidae (Mollusca: Gastropoda: Conoidea) in the Greek Seas with the description of two new species

Abstract Background The Raphitomidae family in the Mediterranean Sea is under revision. Accordingly, new data are of taxonomic and comparative relevance. In this study, new material from the Hellenic Seas is presented. Results The Raphitomidae fauna of Greece was collected and investigated during the period from October 2008 to February 2018. Thirty-five (35) species were identified and their status was compared with existing checklists and other collections. This effort revealed two new Raphitoma species, and one new record for the Mediterranean Sea. Also from the present collection, four species are new records for the East Mediterranean, 10 for the Hellenic fauna and six are reported for second time. The main identification characteristics and baseline ecological information are given and discussed. Conclusions By this report, the Hellenic Raphitomidae biodiversity is enriched by 10 new records, out of which, two are new species, one is new record for the Mediterranean Sea, and four for the East basin

New marine gastropod records for the Hellenic waters

Abstract Background The Hellenic Seas are influenced by on-going environmental changes and the introduction of alien species, which are expected to have an impact on their biodiversity. This study contributes to the knowledge of the Hellenic marine gastropod biodiversity, expanding data over the entire Greek territory, during the period from October 2008 to March 2017. Results This work presents 45 species of gastropods not previously reported from Greece or reported only once, belonging to 19 families. From those species, one (Horologica sp.) is, most probably, an undescribed species, 17 are new for the Eastern Mediterranean Sea and 40 are new for the Hellenic fauna. Main taxonomic characteristics and ecological information such as habitat, distribution and origin, are given and discussed. Conclusions By this report, the Hellenic gastropod biodiversity is enriched by 40 new records, out of which, 17 are new for the Eastern Mediterranean Sea, 4 are Lessepsian migrants previously reported for the Mediterranean Sea and 1 is probably a new species