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Biomedical subjects

D R Sanders

Publications and source records attributed to D R Sanders.

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

Graded nonintersecting transverse incisions for correction of idiopathic astigmatism.

We present the results of a consecutive series of graded transverse (T) incisions for correcting idiopathic astigmatism evaluated by vector analysis, a method not previously used to report T-incision results. In fact, no clinical studies on the results of the T-incision method have been reported. For comparison with conventional reporting methods, the results of graded T incisions on a series of eyes were evaluated, using both vector analysis and simplified analytic procedures. Sixty eyes were evaluated following surgery based on the Thornton guide for astigmatism correction. The mean preoperative cylinder in the series was 1.5 diopters (D) (SD = 0.43, range 1.00 D to 2.25 D); mean postoperative cylinder was 0.4 D (SD = 0.61, range 0 to 3.75 D). The mean decrease of 1.1 D was statistically significant. The results show that it is possible to quantify astigmatism correction using vector analysis.

Adult↗
PubMed1986

Epikeratophakia for keratoconus. The nationwide study.

The nationwide study of epikeratophakia for the treatment of keratoconus involved 69 surgeons in the United States; they operated on 177 eyes as of Dec 31, 1985. In this first report, the results from 35 surgeons involving 82 cases with 30 or more days of follow-up after suture removal are described. In all but two patients, uncorrected visual acuity improved; 17 patients showed improvement of three Snellen lines, and 38 patients showed improvement of four or more lines. The majority of patients' vision returned to within one line of their best corrected acuity; in 78% it was 20/40 or better postoperatively. Eight patients needed no postoperative overrefraction at all. The mean flattening by keratometry readings was 9.36 diopters, and the mean decrease in myopia in terms of spherical equivalent was 5.26 D. No significant changes in intraocular pressure or endothelial cell counts were noted. Some advantages of epikeratophakia for keratoconus over the traditional penetrating keratoplasty include the lack of serious, vision-threatening complications or permanent vision loss, the reversible nature of the surgery, and the absence of potential immunogenic rejection phenomena.

Adolescent↗
PubMed1986

A survey of intraocular lens explantations.

A survey of intraocular lens (IOL) explantations performed during the 1984 calendar year requested dates of implantation and explantation, lens manufacturer, and lens style for anterior chamber, posterior chamber, and iris-supported lenses. The survey was distributed to 3,640 members of the American Society of Cataract and Refractive Surgery and was published in the September 15, 1985, issue of Ocular Surgery News. Information on 1,087 IOL explantations performed during 1984 by approximately 530 surgeons was received. Extrapolation of our survey's responses to the universe of ophthalmic surgeons suggests that the number of IOL explantations ranges from 7,000 to 11,000 each year. The actual numbers and percentages of explantations as well as reported complications vary with the relative percentage of any given manufacturer's lenses implanted and with the popularity of lens styles during the preceding years of implantation. For these reasons, the individual performance of various lenses should be read in the context of this report, considering the time of implantation and the practices that were then in vogue. This survey provides a general picture of IOL explantation but, more importantly, it provides a better structure for a report on 1985 explantations, which will follow.

Corneal Diseases↗
PubMed1986

Progressive hyperopia in radial keratotomy. Long-term follow-up of diamond-knife and metal-blade series.

In an earlier report, the authors demonstrated a trend toward progressive hyperopia in radial keratotomy (RK) patients examined between one and three to four years postoperatively. In those 109 cases, the surgeries were performed using a metal-blade instrument. In the following study, the metal-blade series was updated to a total of 225 procedures, and a more recent series of 300 procedures performed on 228 patients was examined in which a diamond-knife cutting instrument was used. Patients had uncorrected visual acuity determination, cycloplegic refractions with best corrected visual acuity measurements and keratometry measurements. The authors demonstrated a hyperopic shift in the distribution of postoperative spherical equivalent (SE) values across time such that higher proportions of cases in both metal-blade and diamond-knife series were at least 1.0 diopter (D) away from emmetropia at 24 and 48 months than was the case at 12 months after surgery. Regression analysis determined that none of the preoperative or surgical variables known to affect refractive outcome of RK (alone or in combination) could account for the changes in refraction seen during the course of postoperative time. In general, changes in keratometry paralleled refractive changes, but were somewhat smaller in magnitude.

Cornea↗
PubMed1985

Near-UV radiation from the operating microscope and pseudophakic cystoid macular edema.

We performed a prospective randomized study of 297 patients to determine the effect of a UV-blocking filter on the operating microscope on the angiographic incidence of cystoid macular edema in patients undergoing extracapsular surgery with implantation of a posterior chamber lens. Patients were randomly allocated preoperatively to two groups undergoing surgery with or without a UV filter in place. Of the 297 patients, 205 had angiograms readable for the presence or absence of cystoid macular edema. The incidence of aphakic cystoid macular edema in patients without the filter was 21% v 17.3% in the group with a filter. This difference was not significant. The presence of a UV-blocking filter on the operating microscope makes no difference in the angiographic incidence of cystoid macular edema or the visual outcome in these cases.

Cataract Extraction↗
PubMed1985

Intraocular pressure and the corneal endothelium after neodymium-YAG laser posterior capsulotomy. Relative effects of aphakia and pseudophakia.

We studied intraocular pressure (IOP) changes and specular microscopic findings in 118 consecutive neodymium-YAG laser posterior capsulotomy procedures; 37 cases were aphakic, and 81 were pseudophakic. There was a significantly greater rise in IOP one hour after Nd-YAG laser treatment in the aphakic group than in the pseudophakic group (8.2 mm Hg vs 3.5 mm Hg, respectively). At one week postoperatively, IOPs in the aphakic group were still significantly elevated over baseline levels (3.6 mm Hg), while those in the pseudophakic group had returned to baseline levels. Differences in treatment between the aphakic and pseudophakic groups in total number of pulses, average energy, and total energy did not explain the differences in IOP. No significant change in endothelial cell densities was seen between pretreatment measurements and those taken one week after Nd-YAG laser treatment.

Aphakia↗
PubMed1985

Progressive hyperopia with long-term follow-up of radial keratotomy.

A number of studies have documented the reasonable efficacy and safety of radial keratotomy, but most were based upon results obtained one year or less after surgery. This study reviewed 109 consecutive radial keratotomy procedures performed on 79 patients between Nov 10, 1979, and Jan 31, 1981. In addition to a number of earlier postoperative visits, 81 eyes in 55 patients (74.3%) were examined between eight and 18 months postoperatively (a "one-year visit") and again between 31 and 57 months postoperatively (a "four-year visit"). Patients had uncorrected visual acuity determination, cycloplegic refractions with best-corrected visual acuity measurements, and keratometry. Of the 81 eyes, 17 (21.0%) became more myopic between one and four years postoperatively; five (6.2%) remained the same; and 59 (72.8%) became more hyperopic. With a significant change defined as 1.0 diopter or more, two eyes (2.5%) became significantly more myopic at four years; 54 eyes (66.7%) remained within 1.0 D of their one-year spherical equivalent; and 25 (30.9%) became significantly more hyperopic. Changes in keratometry generally paralleled refraction changes.

Adult↗
PubMed1985

Lenticular energy metabolism during exogenous calcium deprivation and during recovery: effects of dextran-40.

Phosphatic metabolites of the intact rabbit lens were quantitated as a function of time by phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy during in vitro incubations at 37 degrees C in calcium-sufficient and calcium-deficient modified Earle's buffer with and without the osmotic agent, Dextran-40. Intralenticular pH was determined from the resonance shift position of inorganic orthophosphate (Pi). Incubation of lenses in calcium-deficient buffer resulted in a pronounced, time-dependent decrease in lenticular adenosine triphosphate (ATP) levels. The half-life of ATP within the lens was 11 hr under these experimental conditions. A concomitant, essentially stoichiometric increase in adenosine diphosphate and Pi levels was observed also. The other phosphatic metabolites were unaffected by exogenous calcium deprivation except for adenosine and inosine monophosphate which accumulated with time. Dextran-40 (6%), which has been shown to prevent lens swelling under these same experimental conditions, did not influence the metabolic responses of the lens to external calcium deprivation and did not facilitate subsequent restoration of lens phosphatic metabolites following restoration of a physiologic calcium concentration to the supporting medium. The Dextran-40 did, however, promote the retention of intralenticular pH environment during the experimental period. These findings suggest that the previously reported Dextran-40-dependent recovery of intralenticular sodium and potassium concentrations to control levels following 10 hr of incubation in calcium-deficient media cannot be attributed to a direct energy-sparing action of Dextran-40 on lenticular energy metabolism. Instead, the mechanistic basis for the action of Dextran-40 would appear to be related to its colloid osmotic properties and its ability to prevent lenticular swelling, which otherwise occurs in the absence of Dextran under these experimental conditions.

Adenosine Diphosphate↗
PubMed1985

Factors affecting pseudophakic cystoid mascular edema: five randomized trials.

We summarize the findings of five randomized prospective, controlled studies that evaluated the following factors associated with the development of cystoid macular edema (CME) following cataract surgery: ultraviolet (UV) light from the operating microscope; postoperative UV light exposure; primary capsulotomy; retrobulbar hyaluronidase; and prostaglandin synthesis in the eye. The following were the major findings: (1) The presence of a UV-light filter on the operating microscope during cataract surgery made no statistically significant difference in the early postoperative (two to six months) angiographic incidence of CME or the visual outcome. (2) A UV-filtering posterior chamber intraocular lens (IOL) resulted in a statistically significant decrease in the early postoperative incidence of angiographic CME in postcataract-surgery patients but did not affect visual acuity. (3) Patients receiving primary capsulotomy during extracapsular cataract surgery showed a statistically significant higher incidence of early postoperative angiographic CME than did patients with an intact posterior capsule. Again there was no difference in visual acuity. (4) The addition of hyaluronidase to the retrobulbar anesthetic injection made no significant difference in the CME rate or postoperative visual results of patients undergoing extracapsular cataract surgery. (5) Patients undergoing IOL implant surgery who received topical indomethacin before surgery and for nine months postoperatively to inhibit prostaglandin synthesis in the eye showed a statistically significant lower incidence of early postoperative angiographic CME than did placebo-treated patients, but there was no significant difference between the two groups in postoperative visual acuity.

Cataract Extraction↗
PubMed1985

Factors affecting predictability of radial keratotomy.

A major criticism of radial keratotomy (RK) has been its lack of predictability, a lack due in large measure to the use of simple correlational statistics assessing the relationship between refractive result and each predictor-variable being evaluated separately. This report utilizes multivariate analysis in an attempt to account for the effects of a number of predictor-variables simultaneously. Variables studied are patient age, optical zone size, number of incisions, mean incision depth, preoperative average keratometry, preoperative average applanation tension, patient sex, and age-sex interrelationship. The area of the optical clear zone selected by the surgeon was found to be the most important factor determining refractive change as a result of RK, explaining one-quarter to one-half of the variability of the procedure. The effects of the other factors and the limitations of the method are discussed. Although this method cannot produce a fully predictive equation, we believe this analysis can serve as a good starting point for beginning RK surgeons and a method by which experienced RK surgeons can improve their techniques.

Adult↗
PubMed1985

Effect of an ultraviolet-filtering intraocular lens on cystoid macular edema.

A prospective double-masked study of 301 patients was undertaken to compare the effect of ultraviolet (UV) filtering in implant intraocular lenses (IOL) on the angiographic incidence of cystoid macular edema (CME) in patients undergoing extracapsular cataract extraction. Patients were randomized to receive either a posterior chamber IOL that contained UV-absorbing chromophore or an identical IOL which did not contain such a chromophore. All patients were scheduled for fluorescein angiography between three and six months after surgery; 228 angiograms were obtained that were readable for the presence or absence of angiographic CME. The mean interval following surgery was 4.3 months. The incidence of CME was 18.8% (21 of 112) in patients who received lenses without UV-filtering chromophore and 9.5% (11 of 116) in patients who received IOLs that contained UV-filtering chromophore. These findings show that UV-filtering-IOLs resulted in a statistically significant (P = 0.03) decrease in the incidence of CME. The presence or absence of the UV-filtering chromophore did not, however, significantly affect visual acuity in the early postoperative period.

Aged↗
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

Steroidal and nonsteroidal anti-inflammatory agents. Effect on postsurgical inflammation and blood-aqueous humor barrier breakdown.

Two hundred and eighty-three patients scheduled to undergo extracapsular cataract extraction with intraocular lens implantation were randomized into four treatment groups that received 1% topical indomethacin and 0.1% topical dexamethasone sodium phosphate, either drug and the other drug's placebo, or two placebos. Inflammation was assessed by clinical grading, and the breakdown of the blood-aqueous barrier was evaluated by slit-lamp anterior segment fluorophotometry. Patients who used either or both anti-inflammatory agents had significantly less inflammation or blood-aqueous barrier breakdown than did those who used neither agent. Also, the use of both topical indomethacin and dexamethasone resulted in less fluorescein leakage during the second postoperative week than did the use of dexamethasone alone. Since this difference could not be detected by clinical measurement, we believe that fluorophotometry is a more sensitive quantitative measure. Clinical assessment of inflammation did correlate with fluorophotometric measurements, as patients with clinically unacceptable inflammation had 3.7 times more fluorescein leakage in the surgically treated eye than did patients with clinically acceptable inflammation.

Administration, Topical↗
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↗
PubMed1984

Radial keratotomy: an overview of the Kansas City study.

The first 290 consecutive eyes (192 patients) to undergo radial keratotomy by one surgeon were evaluated prospectively. All had had complete preoperative evaluation and 269 (93%) were examined one or more years after surgery. Preoperatively, all patients except one had worse than 20/100 uncorrected visual acuity, 65% had less than 20/400, and mean spherical equivalent (SE) was -4.8 diopters. One year postoperatively, 40% of the patients had uncorrected visual acuity of 20/20 or better and 83% had 20/40 or better. The mean change in SE after 1 year was 5.0 diopters, and 60% of eyes were within 1 diopter of emmetropia. Keratometric changes paralleled refractive changes, and both appeared stable within 1 to 3 months. Complications were few and most were transient or well-tolerated. One case of presumably viral disciform keratitis occurring 8 months postoperatively had a three Snellen line decrease in best-corrected acuity 1 year postoperatively. Factors affecting refractive outcome were studied using stepwise multiple regression analysis. Size of the optical zone, depth of incision, patient age, patient sex, intraocular pressure, number of incisions, preoperative average keratometry, and corneal diameter were each found to affect clinical outcome significantly.

Adolescent↗
PubMed1983

Quantitative assessment of postsurgical breakdown of the blood-aqueous barrier.

Breakdown and reestablishment of the blood-aqueous barrier (BAB) following experimental surgical trauma was evaluated by anterior segment slitlamp fluorophotometry. Substantially more fluorescein leakage was caused by 6-mm limbal incisions for at least the first four postoperative days than was produced by 3-mm incisions. Following 3-mm corneal incisions, leakage of fluorescein closely paralleled that of fluorescein-labeled dextran 70 (molecular weight, 70,000) for the first three postoperative days. On the fourth postoperative day, the BAB appeared reestablished to fluorescein-labeled dextran 70 but was still abnormally permeable to fluorescein. Thus, it appears that although fluorescein is the most sensitive technique of demonstrating breakdown of BAB, it may not always be an indicator of large-molecule permeability.

Animals↗