Reliability of simultaneous visual field testing.

OBJECTIVE: To test for differences in reliability and performance between traditional, isolated perimetry and simultaneous testing with 2 patients in the same room. DESIGN: Comparative case series. PARTICIPANTS: A total of 471 eyes of 261 subjects. METHODS: Consecutive patients undergoing Humphrey visual field (VF) testing in the Kellogg Eye Center glaucoma clinic were screened. Patients who underwent VF testing with another patient in the same room ("double field") during the screening interval were included as subjects if a comparison isolated VF from the same patient ("single field") was obtainable from the clinic's records. An individual subject's performance and reliability on his/her double and single fields were compared using a paired t test. In addition, the double fields were stratified by technician-to-patient ratio, and their VF indices were compared using an independent 2-sample t test. MAIN OUTCOME MEASURES: False negatives, false positives, fixation losses, mean deviation, pattern standard deviation, VF index, VF duration, and technician-to-patient ratio. RESULTS: No significant differences between single and double fields were found in the reliability or performance parameters. Test duration was longer in double fields than in single fields (6.1 vs. 5.9 minutes, P < 0.001). There were no significant differences found in reliability or performance indices when the double-field data were stratified by technician-to-patient ratio (1:2 vs. 2:2). CONCLUSIONS: There is no decrement in VF performance or reliability when patients undergo simultaneous testing with another patient in the same room. Busy clinical practices may be able to minimize costs and maximize efficiency by having 1 technician simultaneously supervise more than 1 test-taker in the same space.

The gel state of the vitreous and ascorbate-dependent oxygen consumption: relationship to the etiology of nuclear cataracts.

OBJECTIVE: To investigate the rate and mechanism of oxygen consumption by the vitreous. METHODS: Oxygen consumption was measured with a microrespirometer. Vitreous ascorbate was measured spectrophotometrically and by gas chromatography-mass spectrometry. Vitreous degeneration was related to the rate of oxygen consumption and ascorbate concentration in samples obtained during vitrectomy. RESULTS: Prolonged exposure to oxygen or treatment with ascorbate oxidase eliminated oxygen consumption by the vitreous. Adding ascorbate restored oxygen consumption. Oxygen consumption persisted after boiling or treating the vitreous with the chelating agents EDTA and deferoxamine. In patients undergoing retinal surgery, liquefaction of the vitreous and previous vitrectomy were associated with decreased ascorbate concentration and lower oxygen consumption. CONCLUSIONS: Ascorbate in the vitreous decreases exposure of the lens to oxygen. The catalyst for this reaction is not known, although free iron may contribute. The gel state of the vitreous preserves ascorbate levels, thereby sustaining oxygen consumption. Vitrectomy or advanced vitreous degeneration may increase exposure of the lens to oxygen, promoting the progression of nuclear cataracts. CLINICAL RELEVANCE: Determining how the eye is protected from nuclear cataracts should suggest treatments to reduce their incidence.

Mutational analysis of the Drosophila DNA repair and recombination gene mei-9.

Drosophila mei-9 is essential for several DNA repair and recombination pathways, including nucleotide excision repair (NER), interstrand crosslink repair, and meiotic recombination. To better understand the role of MEI-9 in these processes, we characterized 10 unique mutant alleles of mei-9. These include a P-element insertion that disrupts repair functions but not the meiotic function; three nonsense mutations, one of which has nearly wild-type levels of protein; three missense mutations, one of which disrupts the meiotic function but not repair functions; two small in-frame deletions; and one frameshift.