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Biomedical subjects

M Busin

Publications and source records attributed to M Busin.

At least 55 records · Page 3Linked to original sources
PubMed1987

Combined penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens implantation.

We reviewed 22 cases of triple procedure in the last two years at our institution. Six months postoperatively 21 of the 22 transplanted corneas were clear. One graft for herpetic corneal scarring failed. Best corrected visual acuity was 20/40 or better in 14 patients. The average refractive error was--1.31 +/- 2.30 diopters. Refractive astigmatism was 4 diopters or less in 80% of patients. These results, which compare favorably with previous series, indicate the efficacy and safety of this procedure.

Cataract Extraction↗
PubMed1986

Precarved lyophilized tissue for lamellar keratoplasty in recurrent pterygium.

Thirteen eyes with recurrent pterygia were treated with excision and lamellar keratoplasty using precarved, lyophilized donor cornea. After an average follow-up of 23 months, only one eye (7.7%) required repeat excision. Two eyes (15.4%) had minor recurrences that were asymptomatic and did not progress. Minimal vascularization at the interface between donor and recipient cornea was frequent, but this completely regressed after suture removal and topical corticosteroid treatment. Limitation of movement, when present preoperatively, was improved or eliminated. Best corrected visual acuity was unchanged in eight eyes (61.5%), decreased by one line in two eyes (15.4%), and improved by one or two lines in three eyes (23.1%). Postoperative astigmatism was within 0.5 diopter of the preoperative value in 11 eyes (84.6%); one eye (7.7%) had a postoperative increase of 1 diopter and another eye (7.7%) of 2 diopters.

Adult↗
PubMed1986

Ocular concentration of gentamicin after penetrating keratoplasty.

To determine if the storage of corneal tissue in a preserving medium containing gentamicin results in therapeutically effective concentrations of antibiotics in the ocular tissues after penetrating keratoplasty, we stored rabbit donor corneas in McCarey-Kaufman medium containing 100 micrograms of gentamicin per milliliter for three days before surgery. Gentamicin concentrations were determined by agar-diffusion bioassay in ocular tissues one, two, three, four, and six hours after surgery. On the average, the concentration of antibiotic one hour after surgery was 8.8 micrograms of gentamicin per gram of donor cornea, 6.25 micrograms of gentamicin per milliliter of iris, and 2.8 micrograms of gentamicin per milliliter of aqueous humor. The minimal inhibitory concentration for sensitive strains of Pseudomonas aeruginosa is 1.6 micrograms of gentamicin per milliliter of medium. Thus, gentamicin levels sufficient to inhibit the growth of sensitive bacteria were still present in the donor cornea three hours and in the iris two hours after penetrating keratoplasty. By six hours, only trace amounts of gentamicin were found in the donor cornea and aqueous humor. The presence of gentamicin in ocular tissues after penetrating keratoplasty appears to prolong the antibacterial effect of the preserving medium, and to provide tissue concentrations of antibiotic effective against intraoperative contamination.

Animals↗
PubMed1986

Antibacterial effect of donor corneas stored in gentamicin-enriched McCarey-Kaufman medium.

Penetrating keratoplasty was performed on five pairs of rabbit eyes; one eye of each animal received a donor cornea stored in McCarey-Kaufman (M-K) medium containing gentamicin, and the contralateral eye received a donor cornea stored in M-K medium without gentamicin. At the end of surgery, dilutions of Pseudomonas aeruginosa were introduced into the anterior chamber of both eyes. The eyes receiving gentamicin-enriched corneas showed mild to moderate infection; the contralateral eyes showed significantly more severe infection. The results indicated that donor corneas stored in gentamicin-enriched M-K medium inhibit the growth of bacteria acquired at the time of surgery and thus may improve the safety of such transplantation procedures.

Animals↗
PubMed1986

Epikeratophakia with commercially prepared tissue for the correction of aphakia in adults.

The records of all adult patients at Louisiana State University Eye Center, New Orleans, who underwent epikeratophakia for aphakia with commercially prepared tissue since February 1984 were reviewed. The epikeratophakia lenticule was maintained in 37 (92.5%) of 40 patients; complications required the removal of three tissue lenses. The average refractive error three months after surgery was +0.67 +/- 1.97 diopters; 25 (90%) of 28 patients were within 3 D of emmetropia. At six months, the average refractive error was -0.18 +/- 2.27 D. Fourteen (58%) of 24 patients whose visual acuity was 20/40 or better with spectacles before surgery achieved 20/40 spectacle visual acuity three months after surgery, as did ten (59%) of 17 patients at six months and five (83%) of six patients at 12 months. The results in these recent cases are better than in previously reported series and reaffirm the usefulness of epikeratophakia in the treatment of aphakia.

Adult↗
PubMed1986

The effect of changes in intraocular pressure on corneal curvature after radial keratotomy in the rabbit eye.

Standard radial keratotomy was performed in both eyes of 18 rabbits. Intraocular pressure (IOP) was raised by injection of saline solution into the vitreous cavity at different times after surgery: 8 eyes at one, two, and six weeks and 12 eyes at four months. Keratometric readings at 10, 20, 40, 60, and 80 mmHg were recorded by three independent observers in a masked fashion. The same procedure was performed in eight eyes that had no surgery, as controls. Increments in IOP correlated with significant reductions in corneal power at all times after surgery and for all IOP values in the operated eyes. No changes were observed in the control eyes. The results indicate that variations in IOP, even within physiological limits, may cause changes in corneal curvature after radial keratotomy, and that patients with wide fluctuations in IOP could present a higher risk for postoperative fluctuation in visual acuity after this refractive procedure.

Animals↗
PubMed1986

Comparison of K-Sol and M-K medium for cornea storage: results of penetrating keratoplasty in rabbits.

Five pairs of rabbit corneas were stored for two weeks at 4 degrees C, one of each pair in K-Sol medium, and one in McCarey-/Kaufman (M-K) medium. After transplantation all penetrating keratoplasty grafts became clear and thin. Endothelial cell loss was significantly less in the K-Sol stored corneas. Another five pairs of corneas were stored for two weeks in K-Sol or three days in M-K medium. After penetrating keratoplasty there were no significant differences in clarity, thickness, or endothelial cell loss. The results indicate that K-Sol provides satisfactory medium-term corneal storage compared with short-term storage in M-K medium at refrigerator temperatures.

Animals↗
PubMed1986

The effect of collagen cross-linkage inhibitors on rabbit corneas after radial keratotomy.

The inhibition of collagen cross-linkage by beta-aminopropionitrile (BAPN) and D-penicillamine was tested in an attempt to enhance the myopic correction achieved by radial keratotomy. Two groups of six rabbits each underwent radial keratotomy in both eyes; one eye of each rabbit was treated with BAPN (33% in white petrolatum) or D-penicillamine (1.5 M in sterile water) three times a day for 6 weeks, while the other eye received only vehicle. In spite of previous reports of positive results with BAPN, neither BAPN nor penicillamine was found to affect keratometry readings or corneal topography after radial keratotomy. Our results suggest that factors other than collagen cross-linkage exert major influences in determining the outcome of this refractive procedure.

Aminopropionitrile↗
PubMed1985

Comparison of the effects of Viscoat and Healon on postoperative intraocular pressure.

We compared the effects of Viscoat and Healon on postoperative increases in intraocular pressure in patients undergoing uncomplicated extracapsular cataract extraction with posterior chamber intraocular lens implantation in a prospective, randomized, single-masked study. Eleven eyes received Viscoat and 13 received Healon. The Viscoat or Healon was aspirated from the anterior chamber with the irrigation-aspiration tip of an automated irrigation-aspiration system at the end of the procedure. No prophylactic intraoperative or postoperative ocular hypotensive agents were used. Intraocular pressure was measured at three, six, 12, and 24 hours postoperatively. Compared with preoperative intraocular pressure, postoperative intraocular pressure was significantly increased in both the Viscoat group and the Healon group. Some postoperative intraocular pressures were as high as 50 to 60 mm Hg, despite removal of the viscoelastic substance at the end of surgery. There was no significant difference in the postoperative intraocular pressures of the Viscoat group and the Healon group.

Aged↗
PubMed1985

Analysis of HSV isolated from patients with unilateral and bilateral herpetic keratitis.

Restriction enzyme analysis was utilized to investigate 11 HSV isolates from patients with herpetic keratitis. The electrophoretic profiles of the DNAs indicate that the isolates belong to HSV-1 and are epidemiologically unrelated. Two of the isolates, derived from a patient with simultaneous bilateral herpetic keratitis were further characterized by genetic and phenotypic analyses. These studies showed the following: (i) the two recrudescent lesions were caused by the same HSV-1 isolate; (ii) the isolate yielded two different plaque phenotypes; (iii) these plaques showed different sensitivity to I.D.U.

Acyclovir↗
PubMedDate not supplied

Modified surgical technique for repeated epikeratophakia surgery in aphakic eyes.

BACKGROUND: Incomplete epithelial removal from the peripheral keratectomy at the time of repeat epikeratophakia surgery can lead to interface downgrowth and consequent failure, as observed in the case reported herein. We present a modification of the standard surgical technique aimed at avoiding such complication. METHODS: A 69-year-old white female underwent a third aphakic epikeratophakia modified to reduce the risk of epithelial interface downgrowth, which had caused a previous failure. The aphakic tissue lens, 8.5 mm in diameter, was sutured into a corneal pocket obtained at a deeper level, inside the peripheral keratectomy used for the previous two procedures. RESULTS: Useful visual acuity (20/60) was obtained and the refractive outcome remained stable up to 1 year postoperatively. Epithelial interface downgrowth did not recur. CONCLUSIONS: Despite the possible risk of perforation while undermining the recipient cornea at a deeper level, the modified technique might offer a more effective method of preventing epithelial downgrowth after repeat epikeratophakia surgery.

Aged↗
PubMedDate not supplied

Electron microscopic examination of prelathed, lyophilized tissue used for epikeratophakia in humans.

Morphologic changes secondary to cryolathing and lyophilization have been described in tissue lenses used for epikeratophakia. We report the electron microscopic findings of an aphakic tissue lens which could not be used because of sudden preoperative myocardial infarction of the patient. Scanning electron microscopy revealed the presence of three distinct zones (peripheral, intermediate, and central) on the stromal side of the lens. The surface of the central zone appeared to be the smoothest, as a consequence of the different angle of lathing. The Bowman's layer side of the tissue lens exhibited a uniform, smooth surface. Transmission electron microscopy revealed a largely normal collagenous structure of both stroma and Bowman's layer. Interfibrillary distances were within normal limits. Several giant stromal spaces of various dimensions filled with homogeneous material were observed. Variably preserved keratocytes were a regular finding among the lamellae. Our findings confirmed some of the structural changes previously observed in tissue lenses not used for epikeratophakia in humans. The limited size of a smooth central zone of the posterior surface could explain some postoperative complaints such as persistent glare phenomena, as well as prolonged visual rehabilitation time, especially in those cases where centration of the epi-lens onto the recipient cornea is not optimal.

Cornea↗
PubMedDate not supplied

Epikeratophakia for the correction of myopia: lenticule design and related histopathological findings.

In spite of the numerous changes in surgical technique, epikeratophakia for the correction of myopia is still far from achieving optimal results. The removal rate of myopic lenticules is much higher than that of aphakic or keratoconus lenticules and has prompted the FDA to deny its approval to the industrial production of epi-lenses for the correction of myopia. We report a patient who underwent epikeratophakia for the correction of high myopia in his left eye and required removal of the lenticule because of unsatisfactory visual outcome. The histologic and electron microscopic examination of the removed lenticule revealed the presence of folds in both Bowman's layer and superficial stroma. These had been described in the past and related to the surgical technique used at that time; they were thought to be the cause of poor visual acuity n two patients, and had prompted, therefore, a change in surgical technique. Our findings suggest that the present lenticule design could be responsible for the presence of folds and the consequent poor visual result.

Adult↗
PubMedDate not supplied

In vivo evaluation of epikeratophakia lenses by means of Scheimpflug photography.

The recovery of clarity in frozen, lyophilized human tissue lenticules used for epikeratophakia has been a matter of controversy. According to some authors, several months are necessary for the lenticules to resume normal transparency; others report clinical experience of much shorter times. Up to now, objective documentation of such findings has not been substantiated. We used a Topcon LS-45 camera to photograph four eyes that underwent epikeratophakia, preoperatively and at 2, 4, 6, and 8 weeks after surgery, and analyzed the film negatives by linear microdensitometry. The degree of film blackening, that is the density of the tissue, was expressed graphically by peaks of various height measured in millimeters. Best spectacle corrected Snellen visual acuity was also recorded. Similar measurements of corneal transparency were performed in 20 healthy adult volunteers whose best corrected spectacle visual acuity was 20/20. In the four operated eyes, (two keratoconus, one aphakia, and one myopia), the light scattering was increased in both the host cornea and the donor lenticule. The lenticule had a considerably increased light scattering in all patients at both 2 and 4 weeks after surgery, but was comparable to that of unoperated corneas in three of four patients at 6 weeks.

Adult↗