Bitoric laser in situ keratomileusis for the correction of simple myopic and mixed astigmatism.

OBJECTIVE: To evaluate the safety and efficacy of bitoric laser in situ keratomileusis (LASIK) for the correction of simple myopic and mixed astigmatism. DESIGN: Retrospective, single-center, and noncomparative case series. PARTICIPANTS: Eighty-six eyes of 56 patients were analyzed for this study. Six-month and 1-year follow-up data were available on 86 eyes and 72 eyes, respectively. Eyes were divided in two groups according to the type of astigmatism: myopic astigmatism with low sphere (< -2 diopters) and mixed astigmatism. The range of astigmatism was 1.25 to 7.5 diopters. INTERVENTION: LASIK was performed using the Automated Corneal Shaper (ACS) microkeratome (Bausch & Lomb, Claremont, CA) to create a cornea flap using the 130- or 160-micron thickness plate. A bitoric mid-stromal ablation was performed using the Nidek EC-5000 excimer laser (Nidek Company, Gamagori, Japan). MAIN OUTCOME MEASURES: Uncorrected visual acuity, manifest refraction, and best spectacle-corrected visual acuity were the parameters measured preoperatively and at months 1, 3, 6, and 12. RESULTS: At the last visit, an uncorrected visual acuity of 20/20 or better was achieved in 77% and 68% of the myopic and mixed astigmatism groups, respectively. Ninety-two percent of all eyes had a mean spherical equivalent within +/- 0.50 diopter of emmetropia. A mean decrease in the vectorial magnitude of the astigmatism of 94% and 91% was achieved for those eyes with myopic and mixed astigmatism, respectively. There was no loss of best spectacle-corrected visual acuity. In two eyes, the axis of the positive cylinder was misaligned. CONCLUSION: Bitoric LASIK is an effective procedure to correct myopic and mixed astigmatism. Eighty-five percent of the eyes achieved an uncorrected visual acuity of 20/25 or better and had a final cylinder of 0.5 diopter or less. It is a safe operation, because no eyes lost any lines of best spectacle-corrected visual acuity. Longer follow-up may be needed to assess these results.

Childhood mortality estimated from reports on previous births given by mothers at the time of a maternity: preceding-births technique.

PIP: This paper demostrates that, by using the Preceding-Births technique (Brass 1969), data can be collected to determine indices of the most recent childhood mortality using a totally different approach independent of the age of the mother reporting on the survivorship of previous children. This method is particularly simple since it requires only 1 question on the registration or notification form: is your last child still alive? No complex analysis and no dependence on other data sources or model life tables are necessary. An advantage of this method is the low % of selection bias. These techniques are concerned with the limited use of only that part of the maternity history data concerning mortality of recent births. Their use is recommended particularly for monitoring trends and evaluating intervention. In the interim before full registration exists in less developed countries, this is a valuable and viable means of estimating childhood mortality. Model tables describe distributions of intervals between live births reported from Colombia, Italy, USA, England and Wales; mortality schedules taken from African standards; and an estimation of proportion dead by the Preceding-Births technique in the Solomon Islands.^ieng