Unity of consciousness.

Although there is much talk in various literatures of streams of consciousness, and most of us have an intuitive understanding of such talk, we are far from having a full grasp of what it is that unifies streams of consciousness, binding together the individual experiences that serve as their constituents. In recent years, discussion of this topic has been principally concerned with synchronic unity of consciousness-the form of unity that is exhibited by momentary states of consciousness, or in other words, by time slices or temporal segments of streams. There are two main questions about synchronic unity. First, what is its scope? Are the simultaneous experiences of a single subject necessarily unified? Generally but not necessarily unified? Sometimes unified? And second, what is the nature of synchronic unity? Is it a fundamental phenomenon, and if not, what are the more basic phenomena that constitute it? This essay reviews recent work on these questions, and provides reasons for preferring some answers to others. This article is categorized under: Philosophy > Consciousness Philosophy > Foundations of Cognitive Science Philosophy > Metaphysics.

Intraoperative aberrometry versus preoperative biometry for intraocular lens power selection in axial myopia.

PURPOSE: To compare the accuracy of intraoperative wavefront aberrometry (ORA) and the Hill-radial basis function (RBF) formula with other formulas based on preoperative biometry in predicting residual refractive error after cataract surgery in eyes with axial myopia. SETTING: Private practice, Harrisburg, Pennsylvania, USA. DESIGN: Retrospective consecutive case series. METHODS: Eyes with an axial length (AL) greater than 25.0 mm had cataract extraction with intraocular lens implantation. For each eye, the 1-center Wang-Koch AL-optimized Holladay 1 formula was used to select an IOL targeting emmetropia. Residual refractive error was predicted preoperatively using the SRK/T, Holladay 1 and 2, Barrett Universal II, and Hill-RBF formulas and intraoperatively using wavefront aberrometry. The postoperative refraction was compared with the preoperative and intraoperative predictions. RESULTS: The study comprised 37 patients (51 eyes). The mean numerical errors ± standard error associated with using the SRK/T, Holladay 1, AL-optimized Holladay 1, Holladay 2, Barrett Universal II, and Hill-RBF formulas and intraoperative wavefront aberrometry were 0.20 ± 0.06 diopters (D), 0.33 ± 0.06 D, -0.02 ± 0.06 D, 0.24 ± 0.06 D, 0.19 ± 0.06 D, 0.22 ± 0.06 D, and 0.056 ± 0.06 D, respectively (P < .001). The proportion of patients within ±0.5 D of the predicted error was 74.5%, 62.8%, 82.4%, 79.1%, 73.9%, 76.7%, and 80.4%, respectively (P = .090). Hyperopic outcomes occurred in 70.6%, 76.5%, 49.0%, 74.4%, 76.1%, 74.4%, and 45.1% of the eyes, respectively (P = .007). CONCLUSIONS: Intraoperative wavefront aberrometry was better than all formulas based on preoperative biometry and as effective as the AL-optimized Holladay 1 formula in predicting residual refractive error and reducing hyperopic outcomes. The Hill-RBF formula's performance was similar to that of the fourth-generation formulas.