Incidence of nonarteritic ischemic optic neuropathy following topical clear corneal cataract surgery: survey and meta-analysis.

OBJECTIVE: We estimate the incidence and characteristics of post-cataract-surgery nonarteritic ischemic optic neuropathy (PCNAION) after topical clear corneal cataract extraction (CCCE) in Canada. DESIGN: Canada-wide internet survey and meta-analysis PARTICIPANTS: All certified Canadian ophthalmologists in the Canadian Ophthalmological Society directory, or belonging to a provincial ophthalmology internet group. METHODS: Identical surveys were distributed to 5 regions in Canada. CCCE surgeons were asked to estimate the number of CCCE they had performed in their career, and the number of PCNAION events that occurred within 1 year after CCCE. The results were analyzed using a random effects meta-analysis of proportions for rare events. RESULTS: The estimated survey response rate was 18%-32%. The 182 survey respondents performed a total of 1 499 694 CCCE with 107 events of PCNAION. Twenty-six percent of surgeons had at least one patient with PCNAION. Meta-analysis revealed a pooled estimate incidence of 2.8 PCNAION events (95% confidence interval 1.6-4.7) per 100 000 cataract procedures during the year after cataract surgery. Seventy-seven percent (82/107) of the PCNAION cases occurred within 3 weeks of surgery, and 7 patients had bilateral PCNAION. CONCLUSIONS: PCNAION is a rare complication after topical CCCE. Its incidence is important to estimate for patient care and epidemiologic reasons.

Slits and Robo-2 regulate the coalescence of subsets of olfactory sensory neuron axons within the ventral region of the olfactory bulb.

Olfactory sensory neurons (OSNs) project their axons to second-order neurons in the olfactory bulb (OB) to form a precise glomerular map and these stereotypic connections are crucial for accurate odorant information processing by animals. To form these connections, olfactory sensory neuron (OSN) axons respond to axon guidance molecules that direct their growth and coalescence. We have previously implicated the axon guidance receptor Robo-2 in the accurate coalescence of OSN axons within the dorsal region of the OB (Cho et al., 2011). Herein, we have examined whether Robo-2 and its ligands, the Slits, contribute to the formation of an accurate glomerular map within more ventral regions of the OB. We have ablated expression of Robo-2 in OSNs and assessed the targeting accuracy of axons expressing either the P2 or MOR28 olfactory receptors, which innervate two different regions of the ventral OB. We show that P2-positive axons, which express Robo-2, coalesce into glomeruli more ventrally and form additional glomeruli in the OB of robo-2(lox/lox);OMP-Cre mice. We also demonstrate that Robo-2-mediated targeting of P2 axons along the dorsoventral axis of the OB is controlled by Slit-1 and Slit-3 expression. Interestingly, although MOR28-positive OSNs only express low levels of Robo-2, a reduced number of MOR28-positive glomeruli is observed in the OB of robo-2(lox/lox);OMP-Cre mice. Taken together, our results demonstrate that Slits and Robo-2 are required for the formation of an accurate glomerular map in the ventral region of the OB.