The effect of ethnicity on anatomic success following macular hole surgery: a multicentre cohort study.

PURPOSE: The purpose is to assess the effect of ethnicity on surgical macular hole closure. METHODS: A retrospective cohort study was undertaken in five UK National Health Service Hospitals. We included all patients with known ethnicity undergoing vitrectomy, internal limiting membrane peel, and gas/oil tamponade for all stages of primary full-thickness macular hole (FTMH). The primary outcome was anatomic success, defined as FTMH closure with one operation. The secondary outcome was mean change in best-corrected visual acuity (BCVA) comparing baseline with final review. RESULTS: Of 334 operations, the ethnicity profile comprised 78.7% White patients, 11.7% Black patients, 8.1% Asian patients, and 1.5% in mixed/other ethnicities. Mean age was 69.7 years with 68.5% females. Overall, 280 (83.8%) had anatomic success. Anatomic failure occurred in 38.5% of Black patients versus 12.6% of White patients (relative risk: 1.788; 95% CI: 1.012 to 3.159; P = 0.045). Overall, baseline logarithm of the minimum angle of resolution BCVA improved by 0.34, from 0.95 (95% CI: 0.894 to 1.008) to 0.62 (95% CI: 0.556 to 0.676). Mean BCVA improved by 0.35 in White patients, 0.37 in Black patients, 0.23 in Asian patients, and 0.38 in mixed/other ethnicity (P = 0.689). Greater FTMH minimum linear diameter was associated with an increased risk of anatomic failure (relative risk: 1.004; 95% CI: 1.002 to 1.005; P < 0.0001), whereas better pre-operative BCVA (F [1,19] = 162.90; P < 0.0001) and anatomic success (F [1,19] = 97.69; P < 0.0001) were associated with greater BCVA improvement. Socio-economic status did not significantly influence anatomic success or BCVA change. CONCLUSIONS: Black ethnicity is associated with an approximately twofold greater risk of failed FTMH surgery. The reasons for this difference warrant further study.

An experimental assessment of five indices of retinal vessel tortuosity with the RET-TORT public dataset.

We compare the performance of five indices of retinal vessel tortuosity against sampling rates of vessel centerlines. We consider distance measure, tortuosity density, two curvature-based measures, and a recently introduced slope-chain coding for general curves, never before assessed comparatively with retinal vessels. To enable replication of our results, we use the public dataset for retinal tortuosity, RET-TORT. We find that (1) the tortuosity density index offers good performance overall, but is not always the best performer; (2) curvature-based methods are the best if high-frequency resampling is possible, but (3) are the most sensitive to variations of the number of samples; (4) slope-chain coding performs best at low sampling rates, but the length of the linear elements must be chosen carefully. In general, performance may vary considerably with resampling, suggesting that the choice of a tortuosity index for clinical inference requires attention to numerical details, and ideally standardization thereof.

Strong phylogeographic structure in a sedentary seabird, the Stewart Island Shag (Leucocarbo chalconotus).

New Zealand's endemic Stewart Island Shag (Leucocarbo chalconotus) comprises two regional groups (Otago and Foveaux Strait) that show consistent differentiation in relative frequencies of pied versus dark-bronze morphotypes, the extent of facial carunculation, body size and breeding time. We used modern and ancient DNA (mitochondrial DNA control region one), and morphometric approaches to investigate the phylogeography and taxonomy of L. chalconotus and its closely related sister species, the endemic Chatham Island Shag (L. onslowi). Our analysis shows Leucocarbo shags in southern New Zealand comprise two well-supported clades, each containing both pied and dark-bronze morphs. However, the combined monophyly of these populations is not supported, with the L. chalconotus Otago lineage sister to L. onslowi. Morphometric analysis indicates that Leucocarbo shags from Otago are larger on average than those from Foveaux Strait. Principal co-ordinate analysis of morphometric data showed substantial morphological differentiation between the Otago and Foveaux Strait clades, and L. onslowi. The phylogeographic partitioning detected within L. chalconotus is marked, and such strong structure is rare for phalacrocoracid species. Our phylogenetic results, together with consistent differences in relative proportions of plumage morphs and facial carunculation, and concordant differentiation in body size and breeding time, suggest several alternative evolutionary hypotheses that require further investigation to determine the level of taxonomic distinctiveness that best represents the L. chalconotus Otago and Foveaux Strait clades.