Cryptic Diversity of African Tigerfish (Genus Hydrocynus) Reveals Palaeogeographic Signatures of Linked Neogene Geotectonic Events

The geobiotic history of landscapes can exhibit controls by tectonics over biotic evolution. This causal relationship positions ecologically specialized species as biotic indicators to decipher details of landscape evolution. Phylogeographic statistics that reconstruct spatio-temporal details of evolutionary histories of aquatic species, including fishes, can reveal key events of drainage evolution, notably where geochronological resolution is insufficient. Where geochronological resolution is insufficient, phylogeographic statistics that reconstruct spatio-temporal details of evolutionary histories of aquatic species, notably fishes, can reveal key events of drainage evolution. This study evaluates paleo-environmental causes of mitochondrial DNA (mtDNA) based phylogeographic records of tigerfishes, genus Hydrocynus, in order to reconstruct their evolutionary history in relation to landscape evolution across Africa. Strong geographical structuring in a cytochrome b (cyt-b) gene phylogeny confirms the established morphological diversity of Hydrocynus and reveals the existence of five previously unknown lineages, with Hydrocynus tanzaniae sister to a clade comprising three previously unknown lineages (Groups B, C and D) and H. vittatus. The dated phylogeny constrains the principal cladogenic events that have structured Hydrocynus diversity from the late Miocene to the Plio-Pleistocene (ca. 0–16 Ma). Phylogeographic tests reveal that the diversity and distribution of Hydrocynus reflects a complex history of vicariance and dispersals, whereby range expansions in particular species testify to changes to drainage basins. Principal divergence events in Hydrocynus have interfaced closely with evolving drainage systems across tropical Africa. Tigerfish evolution is attributed to dominant control by pulses of geotectonism across the African plate. Phylogenetic relationships and divergence estimates among the ten mtDNA lineages illustrates where and when local tectonic events modified Africa's Neogene drainage. Haplotypes shared amongst extant Hydrocynus populations across northern Africa testify to recent dispersals that were facilitated by late Neogene connections across the Nilo-Sahelian drainage. These events in tigerfish evolution concur broadly with available geological evidence and reveal prominent control by the African Rift System, evident in the formative events archived in phylogeographic records of tigerfish

Analysis of long-term outcomes for combined pars plana vitrectomy (PPV) and glaucoma tube shunt surgery in eyes with advanced glaucoma

PURPOSE: To analyze 12- and 24-month visual acuity, intraocular pressure, and complications associated with combined pars plana vitrectomy (PPV) and glaucoma tube shunt placement in eyes with glaucoma. PATIENTS AND METHODS: A retrospective chart review was performed of patients with advanced glaucoma who underwent combined PPV and tube shunt surgery from 2006 to 2010. A minimum of 12 months of follow-up was required for their inclusion in the study. Visual acuity, intraocular pressure, complications, and number of glaucoma medications at 1 and 2 years postoperatively were analyzed. RESULTS: Twenty-eight eyes met the inclusion and exclusion criteria. Baseline visual acuity was 20/200 or worse in 14/28 eyes (50.0%) and 20/40 or better in 2/28 eyes (7.1%). Visual acuity remained 20/200 or worse in 50.0% (P=0.921) and 44.4% (P=0.973) of eyes after 1 and 2 years postoperatively, respectively. At baseline, the mean intraocular pressure was 30.4 mm Hg. There was significant improvement in mean IOP at 1 year (14.7 mm Hg, P=0.001) and at 2 years (15.2 mm Hg, P=0.001) postoperatively. Baseline number of glaucoma medications averaged 3.0±1.09 (SD), and improved to 1.8±1.28 (SD) at 1 year (P=0.0002) and to 1.4±1.33 at 2 years (P<0.0001) postoperatively. CONCLUSION: In this retrospective interventional case series, surgical management of advanced glaucoma with a combination of PPV and glaucoma tube shunt resulted in significantly reduced IOP and glaucoma medications at 1 and 2 years postoperatively

Aniridic glaucoma: diagnosis and treatment

Aniridia is a bilateral iris aplasia/hypoplasia, associated with other ocular anomalies arising during the childhood: nystagmus, photophobia, amblyopia, keratopathies, cataract and lens luxation, glaucoma, fovea and optic nerve hypoplasia. In 6-75 % of cases aniridia is accompanied by a dysgenetic secondary glaucoma caused by an iridogoniodysgenesis for abnormal migration of neural crest neuroectodermal cells, and a higher vulnerability of the optic nerve head for possible microstructural alterations in lamina cribrosa. Congenital glaucoma associated with aniridia is uncommon. The poor young patient collaboration for several clinical and instrumental analyses entails in many cases the need of examinations under general anesthesia. Medical therapy represents the first step, whereas low-responsive patients may undergo laser treatments (transscleral diode laser cyclophotocoagulation or cyclocryotherapy) and/or surgery (trabeculectomy with or without antimetabolites). Refractory cases, frequently with an early onset, require glaucoma drainage devices (Molteno implant, Ahmed valve, or Baerveldt tube shunt). A prophylactic goniotomy can be performed with a long-term effectiveness in reducing risks of aniridic glaucoma onset or progression. \ua9 Springer International Publishing Switzerland 2015. All rights are reserved