The relationship of visual acuity, refractive error, and pupil size after radial keratotomy.

To better define the relationship between residual refractive error, uncorrected visual acuity, and pupil diameter, we compared 42 eyes that had an eight-incision radial keratotomy according to the Prospective Evaluation of Radial Keratotomy Study protocol with 42 matched control eyes. The parameters measured were best corrected visual acuity, uncorrected visual acuity, and the change in cycloplegic refraction with enlarging pupil diameter. The best corrected visual acuity was 20/16 in both the radial keratotomy and control groups, but the variability (SD) was higher in the radial keratotomy group. The average uncorrected visual acuity was 0.35 (35%) better in the radial keratotomy group, but the variability was 1.77 times higher. Change in refraction with dilation occurred in 9% of the controls and 36% of the radial keratotomy patients, indicating a significant difference (P = .002). The change in refraction with dilation in the eyes with radial keratotomy was almost equally split between a hyperopic change (17%) and a myopic change (18%), which was much different than in the control eyes, only 2% of which changed in a hyperopic direction and 7% in a myopic direction. The radial keratotomy patients with a myopic change had the best uncorrected visual acuity, indicating that positive spherical aberration yielded the best aspherical surface for uncorrected visual acuity.

Comparison of blood and peritoneal neutrophil activity in rabbits with and without peritonitis.

The neutrophil (polymorphonuclear cell, or PMN) function is an essential component of the host defense against infection. However, infection itself may alter PMN activity. To investigate both the effects of infection on PMN activity and PMN activity on survival, we evaluated control and infected blood and peritoneal PMN phagocytosis, chemotaxis, and superoxide anion production in rabbits with and without peritonitis. Control blood and peritoneal PMNs were obtained from noninfected rabbits which were subjected to intraperitoneal infusion of sterile hypertonic saline. Infected blood and peritoneal PMNs were obtained from rabbits which had undergone appendiceal devascularization and ligation 18 hr earlier. Phagocytosis was similar in all groups except for a threefold increase in normal peritoneal PMNs. Chemotaxis was inhibited by infection in the blood and peritoneal PMNs. Normal peritoneal PMNs also had decreased chemotaxis. Superoxide anion production was comparable in the infected and control blood; however, both control and infected peritoneal PMNs had elevated superoxide anion production. Of the infected rabbits, four died in 5 days or less. Of the six that lived, two developed intraabdominal abscesses. Blood and peritoneal PMN activity was similar in all rabbits despite their outcome. We conclude that (1) blood and peritoneal PMNs have different basal activities and responses to infection; (2) the milieu of the peritoneal cavity appears to alter the PMNs present; and (3) PMN activity did not predict morbidity or mortality.

Aortic saddle embolus. A twenty-year experience.

Clinical experience with aortic saddle embolus (ASE) is not extensive due to the relative infrequent lodging of emboli at the aortic bifurcation. During the period 1962-1982, 26 patients (mean age, 56 years) were treated at the UCLA Medical Center for ASE and followed from 2 to 158 months (mean, 45 months). These cases were reviewed in order to identify features of diagnosis, anticoagulation, and operation which impact on results. All 26 patients presented with bilateral lower extremity ischemia with or without extension of clot to the iliac bifurcation. Ninety-six per cent of emboli were of cardiac origin and one-third occurred in patients who had previous symptoms of chronic lower extremity ischemia. Rest pain and motor/sensory deficits were main complaints in 92% of the patients, but did not become manifest until more than 6 hours, unlike more distal emboli which have an earlier presentation. Preoperative angiography, even in the patient with a history of claudication, has a small role in planning the surgical approach to patients with ASE and, although performed in 11 patients, it influenced operation in only two. Operation within the "golden period" of 6 hours after embolization did not significantly influence outcome after ASE, since 20 patients were operated on more than 6 hours after embolization, with results similar to six patients who were operated on less than 6 hours after embolization. Early high-dose heparinization, used in all patients and maintained for a mean of 12 days, may have contributed to this effect. In 22 patients (85%) Forgarty catheter extraction via bilateral groin approaches was used with a mortality of 14%; only one death was directly attributed to the catheter embolectomy. In 15% of patients, a direct approach on the aorta was selected with a zero mortality rate. Postoperative functional result was excellent with an amputation rate of only 2% (one limb). Re-embolization occurred in seven patients (27%) after discharge, five of whom had not been maintained on Coumadin and two who were not anticoagulated adequately. The authors conclude that the keys to successful treatment of ASE include high dose heparin which is maintained through the perioperative period, embolectomy without preoperative angiography, and maintenance of long-term oral anticoagulation.