Cataract Surgery in High Hyperopia.

BACKGROUND: Although cataract surgery is a well-established and standardised procedure, it can be demanding and associated with higher complication rates in high hyperopia. We present clinical data for highly hyperopic patients who underwent cataract surgery over a 12-year period (2005 - 2016) and at a single centre. PATIENTS AND METHODS: Out of a total of 11 434 cataract operations, 41 highly hyperopic eyes (SN60AT ≥ 31 dpt) were included for analysis. We compared the target spherical equivalent to the final postoperative spherical equivalent for five different formulas. We also reviewed the best corrected distance visual acuity (BCDVA) before and after surgery and any complications. RESULTS: LogMAR BCDVA increased significantly from a mean of 0.5 before to 0.37 after surgery (p = 0.02). The main reasons for the reduced final BCDVA were glaucoma, Fuchs corneal endothelial dystrophy, and age-related macular degeneration. One eye suffered a radial capsule tear and received a sulcus implanted intraocular lens (IOL). There was no statistically significant difference between formulas with respect to aberration of the final spherical equivalent. CONCLUSIONS: Patients with high hyperopia often have ocular comorbidities. Such eyes may be surgically challenging, resulting in reduced benefits from cataract surgery compared to normal eyes.

Investigating the impact of climate change on the lake ecosystem during the late Holocene using a sedimentary record from the southern Arabian Desert, Yemen.

Lake systems respond physically, chemically, and biologically to hydro-climatic change and variability, and these responses are documented in the sediments. Individual proxies and lacustrine environments may respond to climate variations in a nonlinear way, making it difficult to determine the direction and extent of a climatic shift. Here we investigate the response of lake ecosystem to climatic and environmental changes using a suite of paleo-proxies including ostracods, chironomids, and n-alkanes distribution from paleolake 'Gayal el Bazal (Yemen)'. A previous study from this site has provided a continuous, and high-resolution dataset providing an understanding of precipitation during the last ca 1200 years, particularly during Medieval Climate Anomaly (MCA) and Little Ice Age (LIA). However, the response of the lake ecosystem to these changing hydro-climate conditions, including water-level, salinity, and productivity, remains unknown. The n-alkanes dataset shows that during pluvial interval such as the MCA, the lake experienced an increase in nutrient input resulting in enhanced aquatic productivity. Concurrently, ostracods assemblage displays an increased abundance of swimmer species (like Bradleytriebella lineata and Fabaeomiscandona cf. breuili), suggesting an indirect response between ostracods and climate shifts. The chironomid community during the MCA interval is dominated by taxa belonging to the subfamilies of Chironomini, suggesting a warm, shallow, productive environment with macrophyte vegetation. The LIA interval is marked by increased abundance of higher-chain length n-alkanes, suggesting increased contribution from higher plants. Furthermore, ostracod distribution revealed increased abundance of non-swimmer species like Vestalenula cylindrica., which thrive under saline conditions in the lake. Changes in abundances of Tanytarsini during the LIA interval, which are associated with higher oxygen levels, suggest changes in lake productivity. As a result, the overall patterns in biological indicators reveal that their individual abundance and species/tribe distribution fluctuates in response to changes in the climate and hydrological conditions.

A 220,000-year-long continuous large earthquake record on a slow-slipping plate boundary.

Large earthquakes (magnitude ≥ 7.0) are rare, especially along slow-slipping plate boundaries. Lack of large earthquakes in the instrumental record enlarges uncertainty of the recurrence time; the recurrence of large earthquakes is generally determined by extrapolation according to a magnitude-frequency relation. We enhance the seismological catalog of the Dead Sea Fault Zone by including a 220,000-year-long continuous large earthquake record based on seismites from the Dead Sea center. We constrain seismic shaking intensities via computational fluid dynamics modeling and invert them for earthquake magnitude. Our analysis shows that the recurrence time of large earthquakes follows a power-law distribution, with a mean of 1400 ± 160 years. This mean recurrence is notable shorter than the previous estimate of 11,000 years for the past 40,000 years. Our unique record confirms a clustered earthquake recurrence pattern and a group-fault temporal clustering model, and reveals an unexpectedly high seismicity rate on a slow-slipping plate boundary.

Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean.

The Tethys Ocean was compartmentalized into the Mediterranean Sea and Indian Ocean during the early Miocene, yet the exact nature and timing of this disconnection are not well understood. Here we present two new neodymium isotope records from isolated carbonate platforms on both sides of the closing seaway, Malta (outcrop sampling) and the Maldives (IODP Site U1468), to constrain the evolution of past water mass exchange between the present day Mediterranean Sea and Indian Ocean via the Mesopotamian Seaway. Combining these data with box modeling results indicates that water mass exchange was reduced by ~90% in a first step at ca. 20 Ma. The terminal closure of the seaway then coincided with the sea level drop caused by the onset of permanent glaciation of Antarctica at ca. 13.8 Ma. The termination of meridional water mass exchange through the Tethyan Seaway resulted in a global reorganization of currents, paved the way to the development of upwelling in the Arabian Sea and possibly led to a strengthening of South Asian Monsoon.

The prognostic value of retinal vessel analysis in primary open-angle glaucoma.

PURPOSE: To analyse a prognostic value of initial retinal vessel flicker response for the 3-year development of functional (visual field) and morphological (nerve fibre layer thickness) damage progression in primary open-angle glaucoma patients. PATIENTS AND METHODS: Initially, 70 patients were recruited, and flicker response was measured by standardized procedure with the retinal vessel analyser (RVA). Ocular coherence tomography of retinal nerve fibre layer (OCT RNFL) and a visual field testing were performed at beginning and every 6 months for 3 years; 56 patients completed the study. RESULTS: No correlation was found between the progression of visual field (VF) mean defect and retinal nerve fibre layer (RNFL) thinning over 3 years on one and the maximal flicker reaction in arteries and veins on the other side (all p > 0.1). However, the calculated difference of examined parameters in the superior versus inferior retinal halves correlated significantly between the RNFL thinning and the initial maximal flicker response for arteries (p = 0.01) and veins (p = 0.003). CONCLUSION: This longitudinal study did not find a general correlation between initial retinal vessel response to flicker light and the glaucoma damage progression measured by OCT and VF, hence limiting the relevance of the RVA device as a predictor of future glaucomatous damage.

Association between risk factors and glaucomatous damage in untreated primary open-angle glaucoma.

PURPOSE: To analyze an association between the presumed risk factors for glaucoma and the actual extent of glaucomatous damage in untreated primary open-angle glaucoma. PATIENTS AND METHODS: In 50 untreated open-angle glaucoma patients, we analyzed an association between the level of glaucomatous damage and presumed glaucoma risk factors: mean untreated intraocular pressure (IOP) and short-term IOP variability, ocular pulse amplitude, corneal thickness, acral and corneal temperature, retinal arterial diameter and retinal venous diameter, choroidal blood flow (laser Doppler flowmetry flow, velocity, volume), heart rate, and ocular perfusion pressure. Morphologic damage (mean retinal nerve fiber layer thickness, measured by ocular coherence tomography) and functional damage (visual field mean defect) were evaluated separately in 2 forward-stepwise multiple regression models. RESULTS: The mean retinal nerve fiber layer thickness was significantly (P<0.05) associated with IOP (r=-0.35), retinal arterial diameter (r=0.36), and choroidal blood flow (r=0.30); mean defect was associated with ocular perfusion pressure (r=-0.30), laser Doppler flowmetry volume (r=-0.33), and IOP variability (0.36). CONCLUSIONS: Despite small differences between the morphologic and functional glaucomatous damage, IOP and perfusion parameters seem to contribute, at least in part, independently to both.