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Biomedical subjects

M C Kraff

Publications and source records attributed to M C Kraff.

At least 37 records · Page 2Linked to original sources
PubMed1984

Effect of primary capsulotomy with extracapsular surgery on the incidence of pseudophakic cystoid macular edema.

We performed a prospective randomized study of 288 patients to assess the effect of primary capsulotomy on the angiographic incidence of cystoid macular edema in patients undergoing extracapsular surgery with implantation of an intraocular lens. Patients either had a primary capsulotomy or the posterior capsule remained intact immediately following uneventful posterior chamber intraocular lens implantation. Of the 288 patients, 183 (63%) underwent fluorescein angiography. Angiographically confirmed cystoid macular edema occurred significantly more often in the primary capsulotomy group (20 of 93 patients) than in the intact capsule group (four of 71 patients), for an incidence of 21.5% vs 5.6% (P = .003). The cystoid macular edema appeared milder in the intact capsule group; all the patients with angiographically confirmed cystoid macular edema achieved visual acuities of 20/50 or better. The presence of cystoid macular edema made no difference on visual outcome in the intact capsule group. In contrast, the patients with angiographically confirmed cystoid macular edema in the primary capsulotomy group had significantly worse vision than those who did not have cystoid macular edema (P less than .02).

Aged↗
PubMed1984

Prophylaxis and therapy of aphakic cystoid macular edema.

Aphakic cystoid macular edema (ACME) can be a visually significant complication of modern cataract surgery. Prophylaxis of ACME is preferable to therapy of established ACME. Selection of the appropriate cataract operation, control of systemic factors, avoidance of topical catecholamines, control of intraocular inflammation and use of topical or systemic pharmacologic agents may play a role in the prevention of ACME. If it is proven that light toxicity influences the development of ACME, filters in operating microscopes or in intraocular lenses, cataract glasses, or contact lenses may be helpful. Once ACME is present, antiinflammatory therapy has been the main intervention, although its longterm value remains uncertain. Surgical approaches of unproven value have included photocoagulation, vitrectomy, and removal of an intraocular lens.

Adrenal Cortex Hormones↗
PubMed1983

Comparison of empirically derived and theoretical aphakic refraction formulas.

A formula for predicting aphakic refraction from axial length and keratometry measurements was derived from 120 cases, using linear regression analysis, as follows: Psp = 80.4 - 1.65L -0.7K, where P indicates aphakic spectacle power in diopters; L, axial length in millimeters; and K, result of keratometry in diopters. The prediction accuracy of this simple formula was compared with that of a complex theoretic formula based on geometric optics in 205 additional cases. The prediction accuracy of the theoretic and linear regression-derived formulas was virtually identical despite their differences in complexity and derivation. The differences and similarities between theoretic-derived and regression-derived aphakic and pseudophakic prediction formulas are discussed.

Aphakia↗
PubMed1983

The results of posterior chamber lens implantation.

We studied 1,216 consecutive cases where the surgeon's intent was to implant a posterior chamber lens. In 37 cases, the surgeon elected to put in an anterior chamber lens because of events occurring at the time of surgery. In no instance was the intraocular lens procedure aborted and a lens not implanted. In the 37 cases implanted with anterior chamber lenses, 76% had a final visual acuity of 20/40 or better. In the 1,179 cases that had posterior chamber lenses implanted, 90% had visual acuity of 20/40 or better, and only 1% had worse than 20/400 vision. Senile macular degeneration accounted for over one-half of the 104 patients with a visual acuity of 20/40 or worse. Visual results appeared to be age related; 96% of patients who were less than 75-years-old achieved an acuity of 20/40 or better, whereas only 80% of those over 75 years achieved this level. Our results suggest that extracapsular extraction with posterior chamber lens implantation is safe and provides good visual results.

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PubMed1983

Serial corneal endothelial cell loss with lathe-cut and injection-molded posterior chamber intraocular lenses.

We compared endothelial cell loss of patients implanted with lathe-cut posterior chamber lenses and those implanted with injection-molded lenses over a three-year postoperative period. Results were based on more than 2,500 measurements of corneal endothelial density. Although the technique of cataract extraction (anterior chamber phacoemulsification, posterior chamber phacoemulsification, or planned extracapsular extraction) significantly affected cell loss (P less than .01), the type of implant (lathe-cut or injection-molded) did not. Significant continuing endothelial cell loss did not occur during the first three postoperative years with injection-molded lenses. There was, however, a statistically significant 7% to 15% additional cell loss after surgery over the first two to three postoperative years with lathe-cut implants. There have been no cases of corneal endothelial decompensation developing after implantation of injection-molded or lathe-cut lenses. Because a standard field clinical specular microscope was used in this study, cell counting errors cannot be ruled out as a cause of these findings.

Cataract Extraction↗
PubMed1983

Secondary intraocular lens implantation.

The visual, refractive, and surgical results with 190 consecutive secondary implantations of an anterior chamber intraocular lens were studied. Best-corrected postoperative visual acuity was either better than or within 1 Snellen line of best-corrected preoperative vision in 87% of the cases. Vision worsened by more than two Snellen lines in ten cases (5%), which included three cases of retinal detachment and one case of ischemic optic neuropathy; however, in only one case (0.5%) did we feel that the visual decrease was directly attributable to the secondary implantation procedure. We believe that secondary intraocular lens implantation can improve functional visual acuity in aphakic patients, especially those unable to tolerate aphakic correction with contact lenses or spectacles.

Adult↗
PubMed1982

Breakdown and reestablishment of blood-aqueous barrier with implant surgery.

Preoperative and serial postoperative anterior chamber fluorophotometry was performed after oral administration of fluorescein sodium in patients undergoing extracapsular cataract extraction combined with intraocular lens implantation. In placebo-treated eyes, the blood-aqueous barrier was reestablished at three months after surgery. The administration of topical indomethacin before and after surgery markedly decreased aqueous fluorescein concentration, and the blood-aqueous barrier was reestablished within five weeks. Because all patients were given sub-Tenon's injection of steroids immediately after surgery and intensive topical steroid therapy postoperatively, the effect of topical indomethacin was additive to or synergistic with steroids. The addition of topical indomethacin caused a small but statistically significant increase in the postoperative intraocular pressure; this effect lasted nine weeks.

Administration, Topical↗
PubMed1982

Planned extracapsular extraction versus phacoemulsification with IOL implantation: a comparison of concurrent series.

We compared a concurrent series of patients undergoing Shearing posterior chamber lens implantation combined with planned extracapsular extraction (PEC) or with phacoemulsification (KPE). The visual results were significantly better with KPE than with PEC, even after adjustment for differences in patient age, sex, and followup. The KPE procedure averaged 0.27D less cylinder per case than the PEC procedure. The KPE procedure, however, was significantly more traumatic to the corneal endothelium, as estimated clinically at the time of surgery and corroborated by prospective specular microscopy. The surgeon observed no significant differences between postoperative corneal reaction or Descemet's folding in the two groups, although he clinically estimated the anterior chamber reaction to be greater in the PEC patients.

Adult↗
PubMed1982

A comparison of the Digital Biometric Ruler-300 and Echo-oculometer-3000: a report of two hundred cases.

Axial length measurements in 200 patients were performed with the Digital Biometric Ruler (DBR) and the Echo-oculometer with (Echo-osc) and without an oscilloscope (Echo). Measurements taken with the DBR and Echo-osc correlated better with each other than either did with the Echo measurements. In 32% of cases, the DBR and Echo-osc measurements differed by 0.4 mm or more, corresponding to a difference in predicted implant power of 1 diopter (D) or more. In 8% of cases, the measurements differed by 0.8 mm or more, corresponding to a difference in predicted implant power of 2D or more. In spite of these differences in axial length measurement in individual patients, intraocular lens implant power using the SRKTM formula, could be accurately predicted to within 1D of spectacle correction in 75% to 82% of cases, and to within 2D of spectacle correction in 94% to 98% of cases using either the DBR or Echo-osc measurements. Based on the poor correlation of the Echo axial length measurements to the other two, and the poorer implant power prediction accuracy, we do not recommend the use of the Echo-oculometer without an oscilloscope.

Biometry↗
PubMed1982

Prophylaxis of pseudophakic cystoid macular edema with topical indomethacin.

A prospective double-masked study of 500 patients was performed to assess the effect of topical indomethacin on the angiographic incidence of cystoid macular edema (CME) in patients undergoing intraocular lens implant surgery. All patients received either topical indomethacin or placebo before surgery and for nine months after surgery. All patients underwent planned extracapsular extraction (PEC) or posterior chamber phacoemulsification (PC-KPE). Implantation of a posterior chamber lens and a primary capsulotomy were performed in all cases. All cases received postoperative topical corticosteroids. Of the 500 cases, 390 (78%) underwent fluorescein angiography; most were performed between 2 1/2 and 5 months after surgery. The incidence of angiographically confirmed CME was significantly higher in the placebo-treated patients as compared to those treated with indomethacin (18.5% vs 9.6%; P = 0.04). Patients 60 years of age or older had a significantly higher incidence of CME than younger individuals (15% vs. 3.4%; P = 0.03). When corrected for the effects of drug regimen and age, by means of multiple logistic regression, there was no significant correlation between procedure (PEC vs. PC-KPE) and CME rate (P = 0.62). There was no significant difference in postoperative visual acuity between the indomethacin- and placebo-treated patients (P = 0.65).

Adrenal Cortex Hormones↗
PubMed1982

Monitoring for continuing endothelial cell loss with cataract extraction and intraocular lens implantation.

For a period of three years, more than 2,700 endothelial cell density measurements were performed in over 1,000 patients undergoing cataract extraction with and without intraocular lens implantation. We concluded the following from the data: (1) Significant cell loss occurred with all surgical procedures, averaging between 11.6% and 25.6%, depending on type of procedure and implant used; anterior chamber phacoemulsification without intraocular lens implantation caused the most cell loss. (2) Patients with Medallion suture implants produced by one of two manufacturers studied demonstrated statistically significant cell loss during the first (15.6% additional cells lost) and second (22.9% additional cells lost) postoperative years following the initial cell loss due to surgery. This evidence for continuing cell loss with the Medallion suture lens correlated with the clinical observation of an increasing incidence of late bullous keratopathy in these patients. (3) No other surgical procedure or implant type, including Choyce and Shearing implants and Medallion style lenses from another manufacturer, demonstrated any evidence of continuing endothelial cell loss following the initial loss due to surgery.

Cataract Extraction↗
PubMed1980

Specular microscopy in cataract and intraocular lens patients. A report of 564 cases.

We studied 564 patients who underwent cataract surgery, using preoperative and postoperative endothelial cell photographs and corneal thickness measurements. No statistically significant difference was noted in endothelial cell loss between patients with intracapsular cataract extraction (12.6%) and those undergoing posterior chamber phacoemulsification (15.2%). Both procedures had significantly less cell loss than with anterior chamber phacoemulsification (27.3%). Intraocular lens implantation produced a mean endothelial cell loss of 15.8% to 20.9%, depending on surgical technique and implant type. A Choyce-style lens resulted in statistically less cell loss than with other implants. Mean endothelial cell loss was 17.8% with clinically atraumatic and 27.3% with clinically traumatic implantations. Corneal thickness measurements did not correlate with endothelial cell loss or trauma observed clinically at the time of surgery and did not seem helpful in the preoperative evaluation of cataract cases.

Cataract Extraction↗
PubMed1980

Membrane formation after implantation of polyvinyl alcohol-coated intraocular lenses.

Two PVA-coated intraocular lenses were implanted. In the first case there was an acute onset of severe intraocular inflammation and dense membrane formation on the surface of the implant. The inflammation developed on the fifty-third postoperative day in a previously quiet eye. The second case demonstrated a relentless increase in intraocular inflammation that was unresponsive to medical therapy. An acute exacerbation with membrane formation occurred between the fortieth and forty-fifth postoperative days. In both cases the fibrinous membranes and the implants were removed with prompt resolution of symptoms.

Aged↗
PubMed1980

Computerization of intraocular lens data.

We have developed a method of computerization to collect intraocular lens research data in a private office practice. More than 30 separate variables are now being collected on all patients, and over 1300 cases have been studied. Information is transcribed from patient records to data sheets and typed directly into an office Teletype 43 terminal, which is connected by an acoustic coupler to an IBM 370-148 computer. The data are stored in a systems library which is equipped with an editing mode for rapid updating and addition of data. It also allows jobs to be submitted and returned through the remote terminal. The system is compatible with a statistical package which allows a wide range of statistical analyses.

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