Mid-IR band strength, density, refractive index, and thermal evolution study for solid CH2DOH pure and in astrophysical relevant mixtures.

We present a novel experimental study on solid CH2DOH pure and in astrophysical relevant mixtures. Solid samples were accreted under ultra high vacuum conditions at 17 K and were analyzed by mid-infrared transmission spectroscopy. Refractive index, density, and mid-IR band strength values were measured for pure solid CH2DOH. The refractive index was also measured for CH2DOH:H2O, CH2DOH:CO, and CH2DOH:CH3OH mixtures. For all samples, the thermal evolution of the main band profile was studied. We used the interference laser technique (HeNe laser, λ = 543.5 nm) to measure the samples thickness and a numerical method to measure the refractive index starting from the amplitude of the interference curve. We obtained the ice density through the Lorentz-Lorenz relation. To calculate the band strength values we used the linear fit of the integrated band intensities with respect to the column densities. Samples deposited at 17 K were warmed up to their sublimation temperature. Spectra were taken at selected temperatures to study their thermal evolution. The results are discussed in view of their relevance for the interpretation of astronomical IR spectra.

Glare testing in cataract patients: instrument evaluation and identification of sources of methodological error.

This study sought to determine the relative sensitivity of two commercially available glare testers in predicting outdoor acuity in a population of patients with minimal cataracts. Two target optotypes were evaluated: high contrast letters and varying contrast sinusoidal gratings. Although both instruments demonstrated a significant correlation between indoor and outdoor acuity, they showed a significant difference between predicted outdoor acuity and obtained visual acuity. The brightness acuity tester on high intensity was inaccurate in predicting outdoor vision regardless of test optotype, overpredicting glare disability in 76% (average) of the study population. Glare disability overpredictions fell to 8% on the medium setting with +/- 2 lines of vision classified as "no change." Using the same criterion, the Miller-Nadler glare tester overpredicted glare disability in 2% of the cataract population but underpredicted glare disability in 62%. In this study, letter optotypes resulted in less variability than sinusoidal grating stimuli. In addition, we identify several methodological factors to consider before designing a glare experiment. These potential sources of error can influence the outcome of any glare study that compares indoor and outdoor acuity and include the study population, visual stimuli (optotypes), and elements of the outdoor testing situation.

Endoscopic optic nerve decompression for traumatic blindness.

OBJECTIVES: The goal of this study was to compare the outcome of patients with traumatic optic neuropathy (TON) treated with high-dose steroids with the outcome of patients with TON treated with endoscopic optic nerve decompression (EOND) after failing high-dose steroid treatment. METHODS: During this retrospective review of patients with TON seen from 1994 to 1998, all patients were first treated with megadose methylprednisolone for 48 hours. Patients with no improvement or with worsening visual acuity were offered EOND. RESULTS: Eleven of 34 (32%) patients treated with high-dose steroids showed improvement, and 23 (68%) did not. Seventeen of the 23 patients without improvement after high-dose steroid treatment underwent EOND. Fourteen of 17 (82%) surgically treated patients had improved visual acuity, and 3 (18%) did not, with an overall improvement in 25 of 34 (74%) patients (chi(2) = 11. 338, P = 0.0007). CONCLUSION: EOND is an appropriate treatment technique for patients with TON in whom high-dose steroid treatment has failed.

Stage grouping reliability: TNM '97 versus TANIS in laryngeal cancer.

PURPOSE: To compare the correlation of TANIS and TNM '97 with the survival rate in laryngeal cancer. METHODS AND MATERIAL: From 1970 to 1990, 599 patients at the ENT Clinic, University of Ferrara, had a complete follow-up and met the criteria of enrollment. Data were analyzed by means of survival analyses (Kaplan-Meler and Cox algorithms). RESULTS: Both systems showed a significant correlation with the survival rate. TANIS advanced subcategories were better correlated with the mortality rate than TNM stages IVa and IVb. Again, in the final statistical model, TANIS was more highly correlated with survival rate than TNM.

Is the new TNM (1997) the best system for predicting prognosis?

In 1997, the U.I.C.C. (International Union against Cancer) modified the previous TNM stage grouping published in 1987. In the present study, TANIS and TNM '97 systems were compared in order to evaluate their prognostic ability. Data from 164 patients affected by primary squamous cell carcinoma cancers of the oral cavity (n=100) and oropharynx (n=64) were analyzed by means of survival analyses. Both systems showed a significant correlation with survival rate. TANIS yielded better results in association with the survival rate as compared with TNM '97.

Asymmetric inferior oblique overaction and its association with amblyopia in esotropia.

To evaluate the frequency of asymmetric inferior oblique overaction and its relationship to amblyopia, the authors reviewed the records of all patients who presented to Children's Hospital of Dallas with esotropia over a 2-year period. A total of 368 patients were identified and classified as infantile esotropia, acquired accommodative or partially accommodative esotropia, or acquired nonaccommodative esotropia. Two hundred forty-two patients (66%) had no amblyopia, of which 90% had symmetric inferior oblique activity. One hundred twenty-six patients (34%) had amblyopia; of these patients, 93 (74%) had symmetric inferior oblique action. Amblyopia was strongly associated with increased inferior oblique overaction in the amblyopic eye (P less than 0.001). This finding was consistent for all subgroups. The relative risk for having amblyopia as opposed to normal vision in an eye with increased inferior oblique activity relative to the contralateral eye was 5.6 to 8.6 depending on the eye. Amblyopia should be strongly suspected in patients with esotropia and asymmetric inferior oblique activity, specifically in the eye with more inferior oblique overaction.

Evaluation of ocular safety: tirapazamine plus cisplatin in patients with metastatic melanomas.

Ninety-six patients with metastatic melanoma treated with two consecutive tirapazamine-cisplatin combination chemotherapy regimens were followed for signs of therapy-related ocular toxicity. Baseline and follow-up data were obtained such that each patient acted as his own control. A battery of vision-related tests was performed. These included: best corrected visual acuity, color vision, retinal fundus examination and electro-oculograms (EOG). A brief health-related quality of vision test was administered at each follow-up visit to detect and evaluate self-perceived changes in visual status. In the first study, 48 patients received i.v. tirapazamine over 2 h at 260 mg/m2 (group 1) while in the second study 48 patients (group 2) received i.v. tirapazamine at 390 mg/m2. Visual system assessment was conducted at three timepoints: first at baseline, then at 6 weeks post-baseline, i.e. after two courses of chemotherapy and visit two upon discontinuation of therapy. There was no difference in visual acuity between group 1 and group 2 at baseline, follow-up 1 or at follow-up 2. Grouped data indicate that visual acuity was not affected by either dosage of chemotherapy. Group 1 at baseline found 15% below the normal EOG cutoff point, increasing to 23% at follow-up 1 and increasing at follow-up visit 2 to 33%. Group 2 demonstrated the same EOG findings, but the results were more magnified: baseline, 24%; follow-up 1, 44%; and follow-up 2, 44%. After eliminating those with abnormal color vision baselines, 21% (nine of 42) group 1 patients demonstrated abnormal color vision total error scores at follow-up 1 and 16.7% (four of 24) at follow-up 2. Few individuals showed changes in the higher dosage group. With the exception of one person in each dosage group, all changes were along the blue-yellow (tritan) axis, which is associated with acquired color defects. Of 96 patients examined, proven fundus changes were found in only four subjects. These fundus findings included retinal hemorrhages, retinal nerve fiber layer infarcts (cotton wool spots) and small retinal pigment epithelium detachments. There was no systematic statistical significant difference among the various measures of visual system outcome between groups or test times. Data from all tests for individual patients in both groups reveals a sporadic distribution of changes in visual system tests. If toxicity were pronounced, one would expect consistency in the findings and all or most of the assessment tests would be abnormal for a particular patient. However, patients who were abnormal on one measure of acuity were not necessarily abnormal on the other measures.