Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery

Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use

Choroidal Structure after Half-Dose Photodynamic Therapy in Chronic Central Serous Chorioretinopathy

The study aims to analyze the changes produced by half-dose photodynamic therapy (HD-PDT) in the choroid of eyes with chronic central serous chorioretinopathy (CSC) applying the binarization method to spectral domain optical coherence tomography (SDOCT) and OCT Angiography (OCTA) images. SDOCT and OCTA were performed before, one hour, one week, and one month after HD-PDT. Binarization with a modified Niblack method and analysis by ImageJ were applied. An average ratio between luminal part and total structure was calculated. Twenty-two eyes of 21 patients (20 male and 1 female; mean age 54.8 years) were enrolled. A statistically significant reduction of the central choroidal thickness was observed one week (from 407 µm to 362 µm, p = 0.034) and one month (from 407 µm to 341.5 µm, p = 0.0004) after HD-PDT. The baseline average ratio between luminal part and total structure was 33.4% in SDOCT, and 61.1% in OCTA. These values were 35.3% and 61% one hour, 33.9% and 60.4% one week, and 34.5% and 60.6% one month after HD-PDT, respectively. Overall, PDT seems to produce short-term changes on the luminal component of both choriocapillaris and choroid, which return to baseline status after one month from treatment. However, choroid stays significantly thinner after one month, with both luminal and interstitial components significantly reduced

Targeted next generation sequencing in Italian patients with Usher syndrome: Phenotype-genotype correlations

Abstract We report results of DNA analysis with next generation sequencing (NGS) of 21 consecutive Italian patients from 17 unrelated families with clinical diagnosis of Usher syndrome (4 USH1 and 17 USH2) searching for mutations in 11 genes: MYO7A, CDH23, PCDH15, USH1C, USH1G, USH2A, ADGVR1, DFNB31, CLRN1, PDZD7, HARS. Likely causative mutations were found in all patients: 25 pathogenic variants, 18 previously reported and 7 novel, were identified in three genes (USH2A, MYO7A, ADGRV1). All USH1 presented biallelic MYO7A mutations, one USH2 exhibited ADGRV1 mutations, whereas 16 USH2 displayed USH2A mutations. USH1 patients experienced hearing problems very early in life, followed by visual impairment at 1, 4 and 6 years. Visual symptoms were noticed at age 20 in a patient with homozygous novel MYO7A missense mutation c.849G > A. USH2 patients’ auditory symptoms, instead, arose between 11 months and 14 years, while visual impairment occurred later on. A homozygous c.5933_5940del;5950_5960dup in USH2A was detected in one patient with early deafness. One patient with homozygous deletion from exon 23 to 32 in USH2A suffered early visual symptoms. Therefore, the type of mutation in USH2A and MYO7A genes seems to affect the age at which both auditory and visual impairment occur in patients with USH

Changing trends in corneal graft surgery: A ten-year review

AIM: To review indications and corneal tissue use for penetrating and lamellar surgery between 2002 and 2011. METHODS: The surgical reports of corneal grafts performed during 2002-2011, using tissues supplied by the Eye Bank of Piedmont (Italy), were reviewed retrospectively. Patient demographic data, date of intervention, indication for surgery, and surgical technique used were recorded. Surgical techniques included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK). The χ2 test was used to compare the distribution of indications and types of surgical technique used, for corneal grafts done during 2002-2006 versus those done during 2007-2011. RESULTS: The number of corneal grafts increased by 30.7% from 2002-2006 to 2007-2011 (from 1567 to 2048). Comparing the two periods, both main indications and surgical techniques changed significantly. In 2007-2011, the proportion of interventions for aphakic/pseudophakic bullous keratopathy (from 16.8% to 21.3%), graft failure (from 16.4% to 19.1%) and Fuchs endothelial dystrophy (from 12.8% to 16.7%) all increased significantly (P<0.05), while those for keratoconus decreased significantly (from 35.6% to 27.3%; P<0.001). In 2007-2011, the proportion of PK decreased significantly (from 92.4% to 57.2%; P<0.001) while that of EK and DALK went from 0.4% to 30.2% (P<0.001) and from 7.2% to 12.6% (P<0.001) respectively. CONCLUSION: During 2002-2011 the number of interventions increased significantly for corneal endothelial diseases and graft failure. The growing demand for interventions for these diseases corresponded to the widespread adoption of EK techniques. The use of DALK also increased, but more moderately than EK procedures

Indocyanine Green Angiography and Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-Related Macular Degeneration

To compare the capability of indocyanine green angiography (ICGA) and optical coherence tomography angiography (OCTA) in detecting choroidal neovascularization (CNV)