Laser intrastromal keratomileusis for high myopia and myopic astigmatism

BACKGROUND—Laser intrastromal keratomileusis (LASIK) is an evolving technique which enables high degrees of myopia (>8.0 dioptres) and myopic astigmatism to be corrected. This paper describes initial experience with this procedure. It also details the methodology, the results, the problems encountered, and discusses retreatment procedures.
METHODS—51 eyes (48 primary cases and three retreatments) underwent LASIK for simple myopia or compound myopic astigmatism. After the keratotomy was fashioned with a Chiron corneal shaper, the ablation was performed with either a Summit or Meditec excimer laser. The actual preoperative astigmatism ranged from −0.5 D to −6.0 D (in the astigmatic myopic LASIK (AML) series), while the range of preoperative myopia in the combined myopic LASIK (ML) and AML series was −8.0 D to −37.0 D. Of the ML cases, group 1 (−8.0 to −15.0 D (dioptres)), group 2 (> −15.0 to −20.0 D), and group 3 (> −20.0 D) had mean preoperative myopia values (spherical equivalent) of −11.26 D, −16.84 D and −27.78 D. The same groupings (1, 2, and 3) for the AML cases had respective values of −9.702, −17.4, and −23.08. In the AML series the mean preoperative astigmatism was −2.109 D. Follow up ranged from 8 to 27 months (mean 15.8 months). Six of the cases required retreatment.
RESULTS—There was a reduction in best corrected visual acuity (BCVA) (of 1 Snellen line) in seven of the primary cases (14.5 %) (three in the ML group and four in the AML group), and in one of the retreatment cases. The BCVA improved in 28 cases (58%) in the primary treatment group. The mean correction attempted (spherical equivalent) for the ML groups 1, 2, and 3 was 10.51 D, −14.5 D, and −27.78 D, versus a mean correction achieved of −9.445 D, −15.625 D, and −21.571 D. Similarly, for the AML groups, attempted correction values were −9.702 D, −17.4 D, and −23.08 D, while the values achieved were −6.95 D, −51.425 D, and −15.708 D. Regression was minimal and stabilisation of the refractive result was achieved in all groups, except group 3 of the ML series, by the 3 month examination period. The mean postoperative astigmatism in the AML series was −0.531 D. Vector analysis of the AML series showed that the mean surgically induced astigmatism was +0.93 D. The most common complication encountered was undercorrection, which occurred in 35 cases—23 cases in the ML group and 12 cases in the AML series. Twenty eight per cent of the ML cases, and 25% of the AML cases were within plus or minus 1.5 D of the attempted refraction.
CONCLUSION—For the correction of high myopia and myopic astigmatism, LASIK results in less postoperative pain and relatively little subepithelial haze compared with high myopic photorefractive keratectomy. Furthermore, a stable refraction and reasonably predictable outcome occurs much earlier. High myopia up to −37.0 D can be corrected, albeit with some limitations at the extremes of myopia—in terms of the amount of myopia correctable; this represents a limitation of the technique. Retreatment is a technically straightforward and effective way to treat undercorrection. Undercorrection, the main complication seen in our series, should become less common when the ablation algorithms are further refined.

     

Intense pulsed light therapy in the management of hereditary benign telangiectasia.

Hereditary benign telangiectasia is an idiopathic condition that causes considerable cosmetic embarrassment but has eluded successful treatment due to its extensive nature. We report a case of hereditary benign telangiectasia of the lower limbs in which the challenge of treating an extensive vascular lesion is met by using an Intense pulsed light (IPL) source.     

Fetal pancreatic hamartoma

Pancreatic masses are uncommon lesions in the newborn infant. The authors present the first reported case of neonatal pancreatic hamartoma and describe its interesting clinical, histologic, and radiographic aspects.     

Uptake of (methyl-14C)-sisomicin and (methyl-14C)-gentamicin into bacterial cells.

Eight sensitive strains (two Staphylococcus aureus, two Escherichia coli, two Pseudomonas aeruginosa and two Klebsiella pneumoniae) and four resistant Pseudomonas aeruginosa strains were used to study uptake of sisomicin and gentamicin by the bacterial cells. In eleven out of the twelve organisms studied employing (methyl-14C)-sisomicin and (methyl-14C)-gentamicin, uptake of the former was found higher that that of the latter. In one organism, the uptake of the two antibiotics was similar. This higher uptake of sisomicin may help explain the superior potency of the antibiotic in relation to gentamicin.     

Alteration of intestinal microflora following preoperative mechanical preparation of the colon

Summary The effects of vigorous preoperative mechanical cleansing on the microflora of the ileum, intra-abdominal colon and stool were studied in 12 patients. Mechanical bowel preparation, with dietary restriction, cathartics, and enemas, significantly reduced the mean concentration of coliforms only. Obligate anaerobes, the major constituents of the colonic microflora, and other aerobic and microaerophilic intestinal bacteria were not significantly altered. Vigorous mechanical cleansing reduces the total fecal mass, but the residual bowel content harbors microflora which are a potential source of wound infection following colonic operations. Supported in part by grants from the National Aeronautics and Space Administration and the National Institute of Health (7-R22-A1-09851-01).     

Light and electron microscopic studies of antibiotic associated colitis in the hamster

Lincomycin and its analogue, clindamycin, are capable of producing mild to severe colonic mucosal injury in humans (antibiotic associated colitis). Patients with the disorder may have severe diarrhoea, pseudomembranous plaques, confluent pseudomembranes, and/or a frank, diffuse haemorrhagic colitis. The present study was designed to assess the Golden Syrian hamster as an animal model for antibiotic associated colitis and to describe lesions seen in the animal model by light, transmission electron, and scanning electron microscopy. A colitis was produced in Golden Syrian hamsters by oral or parenteral administration of lincomycin, clindamycin, or N-demethyl clindamycin. Animals were killed at intervals and microscopic studies made of sequential morphological changes in the ileum, caecum, and colon. The microscopic lesions in the early stages of the disorder were abnormalities within the brush border, cellular oedema, and hyperaemia. Changes in the intracellular organelles were observed in more severely damaged epithelial cells. Epithelial hyperplasia resulted in the piling up of cells on the mucosal surfaces. In specimens with the most severe damage, complete loss of epithelium from the mucosal surface was observed. Pseudomembranous plaques were occasionally seen. Comparison of the clinical, gross, and histological features of the animal disease with the human disorder suggest that, although minor differences are present, the hamster model is suitable for experimental studies of antibiotic associated colitis.