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Biomedical subjects

O N Serdarevic

Publications and source records attributed to O N Serdarevic.

16 recordsLinked to original sources
PubMed1998

Effects of ciprofloxacin, streptomycin, and gentamicin on rabbit corneal transendothelial electrical potential difference.

PURPOSE: A previous report suggested that high concentrations of ciprofloxacin in the anterior chamber may cause dose-dependent acute corneal decompensation. Therefore we evaluated the effect of varying concentrations of ciprofloxacin in the anterior chamber on the corneal endothelium and compared these effects with those of gentamicin and streptomycin. METHODS: We assessed endothelial transport function by determining transendothelial electrical potential differences (TEPDs) of rabbit corneas. Our control solution was bicarbonate-buffered balanced saline with glucose (BSG), to which we added ciprofloxacin (50, 100, 125, and 150 microg/ml), gentamicin (1,000 and 2,000 microg/ml), and streptomycin (196, 437, and 696 microg/ml). RESULTS: At high concentrations exceeding minimal inhibitory concentrations against 90% of common ocular isolates (MIC90), accelerated decay of TEPDs was seen with all three antibiotics. Adverse effects on TEPDs were noted at concentrations corresponding to >50 times MICs with ciprofloxacin and 40 x MICs with gentamicin, but only 2 times MICs with streptomycin. CONCLUSION: Our study shows that concentrations of ciprofloxacin, gentamicin, and streptomycin below or equal to their MIC90 levels do not adversely affect endothelial transport function in a rabbit model.

Animals↗
PubMed1996

Videokeratoscopy of recipient peripheral corneas in combined penetrating keratoplasty, cataract extraction, and lens implantation.

PURPOSE: We performed a prospective clinical trial to evaluate computerized videokeratoscopic analysis of the peripheral recipient cornea in intraocular lens power calculations for triple procedures: penetrating keratoplasty, cataract extraction, and intraocular lens insertion. METHODS: Patients with Fuchs' dystrophy underwent consecutive triple procedures. Surgery was performed in 16 eyes by a single surgeon (O.N.S.) using a single technique. If videokeratoscopic analysis disclosed dioptric powers greater than 40 diopters in the circumference of the corneal map, the surgeon's average postoperative central corneal power of 46 diopters was used with the regression formula. If dioptric powers less than 40 diopters were detected in the circumference of the corneal map, 45 diopters was used to avoid postoperative hyperopic shifts and to decrease deviation from intended refractive error. Refraction and videokeratoscopic analysis were performed six months after suture removal (18 to 24 months postoperatively). RESULTS: Analysis of covariance demonstrated that preoperative peripheral videokeratoscopic data of the recipient cornea correlated (P = .0001) with postoperative central corneal power, whereas preoperative central corneal power of the recipient cornea did not correlate (P = .35). Deviation from intended refraction (range, -2.54 to +1.22 diopters) was within 2 diopters in 14 eyes (88%) and within 3 diopters in all eyes. No patients had anisometropia greater than 3 diopters. CONCLUSION: Preoperative data from computerized videokeratoscopic analysis of the recipient peripheral cornea correlated with postoperative central corneal power, and improved postoperative refractive outcomes compared with previously reported results of triple procedures.

Cataract Extraction↗
PubMed1996

Penetrating keratoplasty for keratoconus: role of videokeratoscopy and trephine sizing.

PURPOSE: To evaluate whether determining graft-host trephine disparity on the basis of videokeratoscopic data of keratoconus patients having penetrating keratoplasty (PKP) reduces ametropia and to correlate preoperative videokeratoscopic values, posterior axial length (PAL), and trephine disparity with postoperative refractive outcomes. SETTING: Hôtel-Dieu, University of Paris, France. METHODS: This randomized clinical trial comprised 18 keratoconus patients who had PKP. After computerized videokeratoscopic analysis, patients were randomly assigned to a test or control group with matching for midperipheral corneal keratoscopic criteria. One surgeon performed all grafts using the same technique (except for donor button punching with an 8.00 or 8.25 mm blade, depending on preoperative keratoscopy) with suction trephination (8.00) and a running 10-0 nylon suture. The PAL (total axial length minus the distance from the anterior corneal surface to the anterior lens surface) was measured by applanation ultrasonography. Refraction and videokeratoscopic analysis were done 18 months postoperatively (6 months after suture removal). RESULTS: The mean deviation from emmetropia corrected for PAL in test group patients who had trephine sizing based on the hypothesis that preoperative videokeratoscopy is a useful determining factor was 1.12 diopters (D) +/- 0.74 (SD), which was significantly smaller (P = .005) than that in the control group (2.19 +/- 0.85 D). The test group had uncorrected visual acuities of 20/50 or better. Postoperative spherical equivalent was affected by PAL (P = .0001), preoperative keratoscopy (P = .0001), and trephine disparity (P = .01). Central corneal power after grafting was influenced by keratoscopy (P = .0001) and trephine disparity (P = .002). Uncorrected visual acuity was affected by PAL (P = .001) and keratoscopic data (P = .01). CONCLUSIONS: Parameters for reducing ametropia after grafting of keratoconus patients can be developed for each surgeon based on trephine disparity dependent on preoperative keratoscopic values of the recipient midperipheral cornea and PAL. If the PAL is between 19.0 and 21.0 mm, preoperative midperipheral corneal videokeratoscopy to choose same-size or 0.25 mm different donor and recipient trephine blades is useful to achieve refractive results approximating emmetropia with the described technique.

Adolescent↗
PubMed1995

Randomized clinical trial of penetrating keratoplasty. Before and after suture removal comparison of intraoperative and postoperative suture adjustment.

PURPOSE: The authors performed a prospective, randomized clinical trial of penetrating keratoplasty and compared visual acuity, refraction, and topography up to 15 months postoperatively (3 months after suture removal) after intraoperative and postoperative suture adjustment. METHODS: Twenty-five patients undergoing penetrating keratoplasty for avascular corneal pathology were randomly assigned to two groups. All surgery was done by one surgeon using the same technique (except for intraoperative suture adjustment) with suction trephination (8 mm) and a running 10-0 nylon suture. Intraoperative suture adjustment was performed in the test group and was not performed in the control group. Postoperative suture adjustment was done during the first postoperative month and up to 4 months postoperatively in all patients who had more than 3.5 diopters (D) of astigmatism. The running suture was removed at approximately 12 months postoperatively. Refraction and computed topographic analysis to compare patients with intraoperative and postoperative suture adjustment were performed at 1, 3, 6, 9, 12 (before suture removal), and 15 (after suture removal) months. RESULTS: There was less (P = 0.004) topographic astigmatism up to 12 months postoperatively (pre-suture removal) in patients adjusted intraoperatively (mean +/- standard deviation, 1.53 +/- 0.72 D) than in patients adjusted postoperatively (2.83 +/- 1.19 D). After suture removal, at 15 months postoperatively, astigmatism was still less in the intraoperative adjustment group (1.75 +/- 1.04 D) than in the postoperative adjustment group (2.23 +/- 17.2 D), but the authors could not demonstrate statistical significance. After intraoperative adjustment, no significant change in mean astigmatism occurred, and no patient had more than a 1.18-D change in the amount of astigmatism or more than a 22 degrees change in axis (75% < 10 degrees change) after suture removal. Corneas were more regular until suture removal in the group with intraoperative adjustment, but differences decreased after suture removal. Best spectacle-corrected visual acuity was better in the intraoperatively adjusted group until suture removal with no significant changes in best spectacle-corrected visual acuity between 1 and 15 months. Best spectacle-corrected visual acuity improved more slowly after postoperative adjustment and was different at 1 and 15 months (P = 0.0005). CONCLUSION: The authors demonstrated low astigmatism and good visual results at 15 months postoperatively after either intraoperative or postoperative running suture adjustment, but intraoperative suture adjustment permitted more rapid visual rehabilitation, increased safety, and increased refractive stability.

Astigmatism↗
PubMed1994

Randomized clinical trial comparing astigmatism and visual rehabilitation after penetrating keratoplasty with and without intraoperative suture adjustment.

PURPOSE: The authors performed a prospective, randomized clinical trial to compare postoperative astigmatism and visual rehabilitation after penetrating keratoplasty with and without intraoperative suture adjustment. METHODS: Twenty-five patients undergoing penetrating keratoplasty for avascular corneal pathology randomly were assigned to two groups. All surgery was performed by one surgeon (ONS) using the same technique (except for intraoperative suture adjustment) with Hanna trephination (8 mm) and a running 10-0 nylon suture. Postoperative suture adjustment was done during the first postoperative month in all patients who had more than 3.5 diopters of astigmatism. Refraction and computerized topographic analysis were performed at 1 and 6 months postoperatively. RESULTS: Intraoperative suture adjustment significantly decreased postkeratoplasty topographic (P = 0.0001) and refractive (P = 0.0001) astigmatism and improved best spectacle-corrected visual acuity (P = 0.0019) during the first postoperative month. Seventy-seven percent of control patients (mean topographic astigmatism, 4.89 +/- 1.99 D at 1 month), but no patients who underwent intraoperative suture adjustment (mean topographic astigmatism, 1.50 +/- 0.74 D at 1 month), required at least one postoperative suture adjustment that delayed optical stability and increased postoperative complications. At 6 months postoperatively, mean topographic (P = 0.06) and refractive (P = 0.0001) astigmatism were smaller in the intraoperatively adjusted group than in the control group with postoperative suture adjustments. After intraoperative adjustment, best spectacle-corrected visual acuity was better (P = 0.0168, P = 0.0434) and corneal topography was more regular (P = 0.02, P = 0.07, NS) at 1 and 6 months, respectively, than after postoperative adjustment. CONCLUSION: Visual rehabilitation with decreased postkeratoplasty astigmatism and more regular corneal topography was attained more rapidly and safely with intraoperative suture adjustment.

Adult↗
PubMed1993

Pathologic features and immunofluorescent antibody demonstration of ocular microsporidiosis (Encephalitozoon hellem) in seven patients with acquired immunodeficiency syndrome.

We studied the clinicopathologic features of seven patients with acquired immunodeficiency syndrome (AIDS) and ocular microsporidiosis. All patients had decreased levels of CD4-positive cells (mean, 26/ml3) and ocular symptoms; five had bilateral punctate epithelial keratopathy, one had intermittent red eyes with conjunctivitis, and one had red eyes only. Light and electron microscopy of corneal and conjunctival biopsy and cytologic specimens and intact globes disclosed microsporidia belonging to the genus Encephalitozoon. Because E. cuniculi and E. hellem, the two species of the Encephalitozoon genus, are morphologically identical, an immunofluorescent antibody technique was used for species identification. In all seven patients, the agent was identified as E. hellem. Pathologic examination of globes obtained after autopsy disclosed E. hellem infection to be restricted to the corneal and conjunctival epithelium. We studied methods for the routine diagnosis of ocular microsporidiosis in patients with AIDS, including the role of immunofluorescent antibody staining.

AIDS-Related Opportunistic Infections↗
PubMed1993

Successful treatment of microsporidial keratoconjunctivitis with topical fumagillin in a patient with AIDS.

There recently have been several reports of microsporidial keratoconjunctivitis caused by the organism Encephalitozoon hellem. However, treatment of this infection has been largely ineffective. We report a case of a 35-year-old Hispanic woman with AIDS and E. hellem keratoconjunctivitis confirmed with light, electron, and immunofluorescence microscopy that resolved promptly with topical fumagillin, a crystalline antibiotic with proven efficacy against Encephalitozoon species. No corneal or systemic toxicities were noted using the dosage and preparation employed (10 mg/ml suspension in balanced salt solution). An easily prepared, topical fumagillin suspension appears to be a safe, effective treatment for E. hellem keratoconjunctivitis.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Probability studies on the variations of anterior corneal astigmatism].

The probability method of analysis of astigmatism variations respects both astigmatism components, quantity and axis. The two random variable model that we introduce here analyses cylinder variations and axial variations. After describing the contingency table and the probability table. Expectation of each component and its confidence interval are calculated together with the variance and the standard deviation. Covariance and correlation are calculated. If we want to compare different groups we test cylinders with cylinders and axes with axes. This method does not distort reality and is applicable to the semi meridians from 0 degree to 360 degrees. Only large samples of patients can be studied by this method.

Astigmatism↗
PubMed1993

[Vectorial models for analyzing variations of anterior corneal astigmatism].

Several studies have analysed postoperative or spontaneous variations in astigmatism. The methods of quantification of these variations, frequently used in these studies, are based on different ways of calculating: subtraction, vectorial or polar methods: Naylor, Jaffe and Clayman, Cravy, Naeser, Russell et al. and recently, Holladay et al. Although these methods have the advantage of taking into account the axial component of astigmatism and are useful for a single patient, they have many problems and they are more and more numerous (five in the last three years). We have computerized these formulae on a personal computer and studied their performances when the cylinder power decreases without modification of the axes, when the axes are modified without modification of the cylinder power and when the two axes change with the same angular difference. These calculations demonstrate that these formulae are not linear and introduce statistical errors before the statistical decision tests. Moreover, their application is only possible for evaluation of astigmatism axes between 0 degree to 180 degrees and not for semi meridians and corneal topography.

Analysis of Variance↗
PubMed1988

Excimer laser trephination in penetrating keratoplasty. Morphologic features and wound healing.

The imprecision of trephination of donor and recipient corneas is a major factor in post-keratoplasty astigmatism. In order to improve the quality of trephination, the authors developed a rotating slit delivery system for noncontact penetrating keratoplasty trephination using the excimer laser at 193 nm. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and light microscopy (LM) demonstrated the superior quality of excimer-cut buttons and recipient beds as compared with those obtained by free hand and suction trephines in human cadaver and rabbit eyes. The laser trephined more regularly and precisely without distortion of corneal topography and with less damage to adjacent corneal tissue. The authors morphologically examined wound healing at 6 hours, 12 hours, 3 days, 5 days, 2 weeks, 2 months, and 3 months after penetrating keratoplasty with laser and mechanical trephination in an animal autograft model. The laser did not cause any adverse alteration of wound healing processes including cellular migration, proliferation, and production of new tissue.

Animals↗
PubMed1985

Colour wide field specular microscopic investigation of corneal surface disorders.

Colour wide field specular microscopy (WFSM) may be used to examine different phases of corneal surface pathology in vivo. A soft contact lens facilitates colour differentiation of cell surface variations by interference. Pathologic states may be characterised by modifications in apparent cell colour, brightness, morphology and configuration. Cell brightness is altered by interference phenomena, cell surface irregularities (microprojections), homogeneity of substances covering cells, intracellular components and changes in indices of refraction at the interfaces between the cell surface and the tear layers. Colour photography has been helpful in deciding which intensity variations may be due to interference effects.

Adult↗
PubMedDate not supplied

[Trephination using an Excimer laser].

We compared histologically and ultrastructurally donor buttons and recipient beds trephined mechanically with those trephined by the Excimer laser at 193 nm. The laser allowed for superior cutting precision and perfect centering. This non-contact method obviated the need for any pressure or suction during trephination, thereby eliminating problems associated with distortion of corneal topography. We studied wound healing after penetrating keratoplasty with mechanical and laser trephination in an animal model. The laser did not adversely affect wound healing processes.

Animals↗