Clinical applications of volumetric analysis in the human orbit

Purpose: Orbital volume measurements comprise an essential clinical tool for managing several morbidities of the orbital area. In the presented work, wein vestigate methods that can provide precise measurements of the orbital volumeand its contents (eye globe, extraocular muscles, optic nerve). Furthermore, clinical evaluation of these calculations is provided by examination of patients affected with orbital disease. Methods: We tested manual, semi-automated and fully automated methods for their validity and repeatability in orbital, eyeball, muscle and nerve volumetry. Methods were applied in computed tomography and magnetic resonance imaging series. Estimations were expanded in patients with high myopia and hyperopia where there is significant imbalance between eyeball position and orbital volume. Moreover, patients affected by thyroid eye disease underwent volume measurements with a view to evaluate extraocular muscle volume and disease status. Results: Methods of manual planimetry and semi-automated stereology were selected for further analysis regarding their validity. An algorithmic approach of volume measurements for the orbit and its contents was set. In the clinical part of this work, the effective orbital volume was measured in patients with high myopia and clinical correlations between volumes and anthropometric variables were examined. In patients affected by thyroid eye disease, 3D muscle volumetry was performed and results were compared to standard 2D evaluation of muscle diameter for estimating disease status. Conclusions: The human orbit is prone to several pathologies including inflammatory disease, tumors, congenital mal formations and fractures of its walls. Alterations in orbital volume can affect the harmonious anatomy between the fine structures of the orbit and may manifest with symptoms such as exophthalmos, enophthalmos and diplopia. Precise measurement of the orbital volume is of utmost importance for performing orbital surgery, as vulnerable vessels and nerves can be damaged during surgical approach. In daily practice, orbital volume measurement is often underestimated due to the laborious and time consuming methods. Objective approaches are often used instead which may lead to in accurate results. By applying the systemic approach along with the presented algorithms we can achieve meaningful results and minimize the required time for calculations.Σκοπός: Η ποσοτικοποίηση του όγκου του κόγχου αλλά και των περιεχόμενων δομών του κόγχου είναι ένα απαραίτητο εργαλείο, για την διαχείριση πολλών παθολογικών καταστάσεων που επηρεάζουν την περιοχή. Στη παρούσα εργασία εξετάζονται οι μέθοδοι μέσω των οποίων μπορούν να πραγματοποιηθούν έγκυρες μετρήσεις στον οφθαλμικό κόγχο και στις εσωτερικές δομές του. Στη συνέχεια γίνεται κλινική συνεκτίμηση των ποσοτικών αποτελεσμάτων σε ασθενείς που εμφανίζουν συμπτωματολογία λόγω μορφολογικών αλλαγών στο κόγχο. Μέθοδοι: Μελετήθηκαν χειροκίνητες, ημι-αυτοματοποιημένες αλλά και πλήρως αυτοματοποιημένες μέθοδοι ως προς την αξιοπιστία και την επαναληψιμότητα τους για τη ποσοτικοποίηση του όγκου του κόγχου, του οφθαλμικού βολβού, των εξοφθάλμιων μυών και του οπτικού νεύρου. Οι μέθοδοι εφαρμόστηκαν σε ακολουθίες από υπολογιστική τομογραφία και απεικόνιση μαγνητικού συντονισμού. Στη συνέχεια οι μετρήσεις πραγματοποιήθηκαν σε ασθενείς με υψηλή μυωπία αλλά και υπερμετρωπία στους οποίους παρατηρείται διαταραχή στη θέση του βολβού εντός του κόγχου όπως επίσης και στο μετρούμενο ζωτικό χώρο του κόγχου. Τέλος, πραγματοποιήθηκαν μετρήσεις σε ασθενείς με θυρεοειδική οφθαλμοπάθεια με έμφαση στην ογκομέτρηση των διογκωμένων εξοφθάλμιων μυών. Αποτελέσματα: Οι μέθοδοι της πλανιμετρίας και της στερεολογίας ήταν αυτές που επιλέχθηκαν για την περαιτέρω ανάλυση ως προς την αξιοπιστία των μετρήσεων. Θεσπίστηκαν αλγόριθμοι προσέγγισης για την ποσοτικοποίηση του όγκου του κόγχου και των δομών του. Οι μέθοδοι εφαρμόστηκαν με επιτυχία τόσο σε ζωικά μοντέλα όσο και σε ανθρώπους. Στο κλινικό μέρος της εργασίας, ποσοτικοποιήθηκε ο ζωτικός χώρος του κόγχου σε ασθενείς με υψηλή μυωπία και πραγματοποιήθηκαν συσχετίσεις με μετρήσεις του αξονικού μήκους του βολβού και ανθρωπομετρικών στοιχείων όπως η σωματοδομή και η περίμετρος κεφαλής. Σε ασθενείς προσβεβλημένους από θυρεοειδική οφθαλμοπάθεια πραγματοποιήθηκε τρισδιάστατη ογκομέτρηση των μυών και συγκρίθηκε με την δισδιάστατη απεικόνιση των εξοφθάλμιων μυών για την εκτίμηση της βαρύτητας της νόσου. Συμπεράσματα: Ο οφθαλμικός κόγχος επηρεάζεται φλεγμονώδεις παθήσεις, όγκους, συγγενείς δυσπλασίες και κατάγματα των τοιχωμάτων του. Αλλαγές στον όγκο της κογχικής κοιλότητας θα διαταράξουν την αρμονική σχέση μεταξύ των δομών και θα οδηγήσουν σε συμπτωματολογία όπως εξόφθαλμος, ενόφθαλμος και διπλωπία. Η ακριβής ογκομέτρηση της κογχικής κοιλότητας είναι ύψιστης σημασίας για την χειρουργική του κόγχου, ώστε να οριοθετηθούν περιοχές ασφαλούς προσπέλασης προεγχειρητικά με ελαχιστοποίηση του κινδύνου τραυματισμού. Στην σημερινή κλινική πρακτική, πολλές φορές η αξία της ογκομέτρησης υποτιμάται, ενώ λόγω των χρονοβόρων διαδικασιών συχνά υποκαθίσταται από υποκειμενικές και συχνά ανακριβείς προσεγγίσεις. Με τους αλγόριθμους προσέγγισης και την συστηματική μεθοδολογία που παρουσιάστηκε επιτυγχάνονται ικανοποιητικά αποτελέσματα με παράλληλη ελαχιστοποίηση του χρόνου μέτρησης

Progression of Macular Atrophy in Patients Receiving Long-Term Anti-VEGF Therapy for Age-Related Macular Degeneration: Real-Life Data

Purpose: This study aimed to evaluate the progression of macular atrophy (MA) based on near-infrared reflectance (NIR) and optical coherence tomography (OCT) images, in patients with age-related macular degeneration (AMD), receiving anti-vascular endothelial growth factor (anti-VEGF) treatment for at least a 6-year period. Materials and Methods: This retrospective study included 53 naïve patients (53 eyes) with neovascular AMD from 2 centers, who were treated with anti-VEGF intravitreal injections and had no MA at baseline. MA was evaluated in an annual basis using NIR images, while all available OCT images were used to confirm that the atrophic area fulfilled the criteria proposed by the Classification of Atrophy Meetings (CAM) group for complete retinal pigment epithelium and outer retinal atrophy. Incidence and progression of MA were evaluated. Associations with best-corrected visual acuity (BCVA) and total number of injections were also studied. Results: Treatment duration of our patients was 7.34 ± 1.54 years. The mean number of anti-VEGF injections was 24.4 ± 13.6. BCVA at baseline was 0.38 ± 0.27 logMAR, while at the final visit, it was 0.60 ± 0.35 logMAR (p = 0.731). The cumulative incidence of new MA at years 1, 2, 3, 4, 5, and 6 was 1.89%, 18.87%, 32.08%, 39.62%, 49.06%, and 50.94%, respectively. In patients who developed MA, mean MA area increased from zero at baseline to 5.66 ± 7.18 mm2 at the final visit. The estimated annual enlargement of MA was 0.45 mm/year based on square root transformation (1.12 mm2/year, untransformed data). MA progression does not appear to be significantly associated with age (R = 0.055; p = 0.784), gender (R = 0.113; p = 0.576), BCVA (R = 0.168; p = 0.404), and total number of injections (R = 0.133; p = 0.255). Conclusion: In this real-life setting, half of the neovascular AMD patients under anti-VEGF treatment, without MA at therapy initiation, developed MA over a period of at least 6 years. In this work, the number of injections did not seem to have a significant association with MA progression.</p

Pre-operative intravitreal dexamethasone implant in patients with refractory diabetic macular edema undergoing cataract surgery

To examine preoperative use of intravitreal dexamethasone implant in patients with refractory diabetic macular edema (DME) undergoing cataract surgery. Participants in this study were 17 patients with DME refractory to previous treatment with anti-vascular endothelial growth factor agents or dexamethasone implant, and co-existent cataract. All participants received intravitreal dexamethasone implant at baseline and underwent phacoemulsification within one month after its insertion. Best-corrected visual acuity (BCVA) and central subfield thickness (CST) changes between baseline, time of cataract surgery and postoperative months 1, 2 and 3 were evaluated. At month 1 after surgery, BCVA improved significantly from 42.3 ± 9.6 to 58.7 ± 11.9 letters compared to baseline (p &lt; 0.001) and the improvement was sustained at month 2 and month 3 postoperatively. One month postoperatively, CST improved significantly compared to baseline (p &lt; 0.001) and the improvement was sustained at month 2 (p &lt; 0.001), while at month 3 CST started to increase, but remained significantly lower than baseline (p = 0.003). At month 3 postoperatively, 35.3% of patients presented recurrence of ME. Patients with refractory DME and cataract can safely undergo phacoemulsification when dexamethasone implant is inserted one month prior to surgery to ensure adequate control of postoperative inflammation and prevent deterioration of ME. © 2020, The Author(s)

Evolution of macular atrophy in eyes with neovascular age-related macular degeneration compared to fellow non-neovascular eyes

Purpose Τo evaluate the evolution of macular atrophy (MA) in patients with neovascular AMD (nAMD), compared with their fellow eyes exhibiting dry AMD (dAMD). Methods This retrospective study included 124 patients from three centers treated with anti-VEGF in their nAMD eye and having dAMD in the fellow eye. Patients without MA at baseline were analyzed to study the time to first MA development. Synchronous and unsynchronous time course of MA was also studied. MA was evaluated using near-infrared images, while all available optical coherence tomography (OCT) images were used to confirm the criteria proposed by the Classification of Atrophy Meetings group for complete MA. Results MA first detection in nAMD eyes increased significantly from year 2 to 6 compared to dAMD eyes. Over the study’s follow-up, 45.1% of nAMD-E developed MA, compared to 16.5% of fellow eyes ( p &lt; 0.001). When MA in the two eyes was compared in a synchronous paired manner over 4 years, nAMD eyes had an average MA progression rate of 0.275 mm/year versus 0.110 mm/year in their fellow dAMD eyes. Multivariate ANOVA revealed significant time ( p &lt; 0.001), eye ( p = 0.003), and time-eye interaction ( p &lt; 0.001) effects. However, when MA did develop in dAMD eyes and was compared in an asynchronous manner to MA of nAMD eyes, it was found to progress faster in dAMD eyes (dAMD: 0.295 mm/year vs. nAMD: 0.176 mm/year) with a significant time-eye interaction ( p = 0.015). Conclusions In this study, a significant difference in MA incidence and progression was documented in eyes with nAMD under treatment, compared to fellow eye exhibiting dAMD. Eyes with nAMD tended to develop more MA compared to fellow dAMD eyes. However, when atrophy did develop in the fellow dAMD eyes, it progressed faster over time compared to MA in nAMD eyes.</p

Extraocular Muscle Volumetry for Assessment of Thyroid Eye Disease

In this study we evaluate the diagnostic accuracy of extraocular muscle volumetry in detecting thyroid eye disease and to compare the results with simple measurements of maximal medial rectus (MR) diameter