Express saccades in distinct populations: east, west, and in‑between

Express saccades are low latency (80–130 ms), visually guided saccades. While their occurrence is encouraged by the use of gap tasks (the fixation target is extinguished 200 ms prior to the saccade target appearing) and suppressed by the use of overlap tasks (the fixation target remains present when the saccade target appears), there are some healthy, adult participants, “express saccade makers” (ESMs), who persist in generating high proportions (> 30%) of express saccades in overlap conditions. These participants are encountered much more frequently in Chinese participant groups than amongst the Caucasian participants tested to date. What is not known is whether this high number of ESMs is only a feature of Chinese participant groups. More broadly, there are few comparative studies of saccade behaviour across large participant groups drawn from different populations. We, therefore, tested an independent group of 70 healthy adult Egyptian participants, using the same equipment and procedures as employed in the previous studies. Each participant was exposed to two blocks of 200 gap, and two blocks of 200 overlap trials, with block order counterbalanced. Results from the Schwartz Value Survey were used to confirm that this group of participants was culturally distinct from the Chinese and Caucasian (white British) groups tested previously. Fourteen percent (10/70) of this new group were ESMs, and the pattern of latency distribution in these ESMs was identical to that identified in the other participant groups, with a prominent peak in the express latency range in overlap conditions. Overall, we identified three modes in the distribution of saccade latency in overlap conditions, the timing of which (express peak at 110 ms, subsequent peaks at 160 and 210 ms) were strikingly consistent with our previous observations. That these behavioural patterns of saccade latency are observed consistently in large participant groups, drawn from geographically, ethnically, and culturally distinct populations, suggests that they relate to the underlying architecture of the saccade system

Second Primary Tumors in Retinoblastoma

Advances in the diagnosis and treatment of retinoblastoma have vastly improved patient outcomes. In developed countries, the most common cause of death in patients with heritable retinoblastoma is now a second primary tumor occurring in retinoblastoma survivors; many of these second primaries can be avoided by the reduced use of radiation. Mesenchymal tumors including primitive neuroectodermal tumors, bone and soft tissue sarcomas, leiomyomas, lipomas, cutaneous melanomas, and gliomas are the most common types of the second primary tumors in retinoblastoma survivors. Osteogenic sarcoma is the most common type of second primary tumor particularly in younger patients. Widespread use of systemic chemotherapy only started in the mid-1990s, so it is still too early to know its long-term risk of second primary tumors. Ophthalmic arterial chemotherapy has been widely used for only a few years and, while a major goal of this therapy is to reduce systemic exposure to chemotherapy, a significant amount of radiation exposure to the orbit is required for the fluoroscopy needed to cannulate the ophthalmic artery. Thus, it will be many years before we know the long-term risk of ocular tumors associated with ophthalmic arterial chemotherapy. Regardless of the therapy used to treat intraocular retinoblastoma, it is important to provide lifelong surveillance for second primary tumors that may arise in the orbit and elsewhere in patients with germline retinoblastoma