SIGNIFICANCE Vision screenings are conducted to detect significant refractive errors, amblyopia, and ocular diseases. Vision screening devices are desired to have high testability, sensitivity, and specificity. Spot has demonstrated high testability, but previous reports suggest that the Spot has low sensitivity for detecting amblyogenic hyperopia and moderate sensitivity for amblyogenic astigmatism. PURPOSE This study assessed the concurrent validity of detecting amblyogenic refractive errors by the Spot (v.1.1.50; Welch Allyn Inc., Skaneateles Falls, NY) compared with cycloplegic retinoscopy. METHODS A total of 475 subjects (24 to 96 months) were screened by Spot and then received a masked comprehensive examination. Sensitivity and specificity, Bland-Altman plot, receiver operating characteristic area under the curve, and paired t test were evaluated by comparing the results of the Spot (v1.1.50) using the manufacturer referral criteria with the results of the comprehensive examination using the 2013 American Association for Pediatric Ophthalmology and Strabismus criteria. RESULTS The Spot (v.1.1.50) referred 107 subjects (22.53%) for the following: 18.73% (89/475) astigmatism, 4.63% (22/475) myopia, 0.42% (2/475) hyperopia, and 2.11% (10/475) anisometropia. The sensitivity and specificity of the Spot vision screener for detecting amblyogenic risk factors were 86.08% (95% confidence interval [CI], 76.45 to 92.84%) and 90.15% (95% CI, 86.78 to 92.90%). Areas under the curve were 0.906 (95% CI, 0.836 to 0.976) for hyperopia, 0.887 (95% CI, 0.803 to 0.972) for spherical equivalent, and 0.914 (95% CI, 0.866 to 0.962) for astigmatism. A modified hyperopia criteria cutoff of greater than +1.06 D improved the sensitivity from 25 to 80% with 90% specificity. The current cutoff criterion, greater than −1.75 D, for astigmatism seemed optimal. CONCLUSIONS This study shows that the Spot vision screener accurately detects low spherical refractive errors and astigmatism. Lowering the hyperopia cutoff criteria from the current Spot screener referral criteria improves the sensitivity with desired (high) specificity.

A significant number of individuals who obtain contact lenses illegally from unauthorized sources are young adults. Most unauthorized sellers reviewed did not adhere to the proper protocol for selling contact lenses or instruct their customers on proper lens wear and care. A significant percentage of optometrists responding to the survey reported complications associated with contact lenses purchased through unauthorized sources, suggesting that the risk of contact lens-related complications increases when the lenses are purchased from one of these sources.

The basic Pestov detector module is shown in l•`ig. 2. lt consists oi two elec 2 Design and Mechanical Construction of the Counter a two-dimensional reconstruction oi the spark location. ionizing particle (KHP). The counter is read out via strip lines, which allows a pressure of l2 bar. which yields l 5 primary electrons from a minimum is possible at twice the threshold voltage (~6 The counter opera.tes at area of the anode remains sensitive. .~\ time resolution as good as 25 ps (r.m.s.) a limited area ol the semi-conductive anode (~ l 2 mmz), while the remaining discharge local, thus increasing the rate capability. The spark discha.rges only use of a semi-conductive anode and of a special gas mixture that keeps the gaseous parallel-plate detector working in the streamer/spark mode. lt makes The Pestov Spark Counter [1,2], schematically shown in Fig. l, is a. single-gap,

The new 1.4 MeV/u prestripper linac at GSI will provide intense ion beams to fill the synchrotron SIS to the space charge limit for all elements up to uranium. The design mass to charge ratio A/q is 65, the effective acceleration voltage of the 30 m long LINAC is up to 91 MV. The design beam current in emA is 0.25·A/q, i.e. 15 mA of U 4+. This linac will replace the 27 MHz Unilac Wideröe section which was designed for A/q-values below 24. All cavities of the new linac are operated in the H 110 -mode. The 9.2 m long IH-RFQ with an energy profile from 2.2 keV/u to 120 keV/u has been completed and rf tuned. RF power tests were performed successfully on 2 out of 10 tank modules. The drift tube linac consists of two 42 MV IH cavities. The 'Combined Zero Degree Structure' KONUS allows to accelerate the beam by a total number of 99 gaps with only 5 quadrupole triplet lenses for transverse focusing.The experience from the construction and from the rf tuning of all cavities is reported as well as the measured quality and shunt impedance values. The running in of the new prestripper linac is scheduled from April to September 1999.

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