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Biomedical subjects

B L Lundh

Publications and source records attributed to B L Lundh.

At least 19 recordsLinked to original sources
PubMed2003

Bilateral same day phacoemulsification: 220 cases retrospectively reviewed.

BACKGROUND/AIMS: The relative frequency, basic patient data, results, and complications of planned same day bilateral phacoemulsification were studied from April 1999 to May 2001 at the Department of Ophthalmology, Linköping University Hospital, Sweden. METHODS: Retrospective study of patient records (n=220) regarding preoperative and postoperative visual acuity, applied indications, concurrent disease, preoperative, peroperative, and postoperative complications, and number of unplanned postoperative visits. The monthly rate of bilateral phacoemulsification to all cataract procedures was monitored. RESULTS: Mean corrected preoperative visual acuity was 0.27 (worse eye) and 0.39 (better eye), and postoperatively (all eyes) 0.71. Visual acuity was 0.5 or better in 78% of eyes. Preoperative considerations included type of cataract, to avoid anisometropia, social circumstances, and concurrent eye disease. Reasons for unplanned postoperative visits included secondary cataract (n=10), iritis (n=6), corneal oedema (n=3), cortex in the anterior chamber (n=2), and unilateral endophthalmitis (n=2). During the study period, 10.5% of patients were operated upon bilaterally on the same day. CONCLUSIONS: Same day bilateral phacoemulsification was found to be a safe and cost effective way of rapidly rehabilitating selected cataract patients. The patient must be informed of the added potential risks as well as the benefits of the procedure.

Adult↗
PubMed2000

Colour contrast sensitivity in cataract and pseudophakia.

PURPOSE: To study the influence of cataract on peripheral and central colour contrast sensitivity. METHODS: Peripheral and central colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes. Included were 30 patients with cataract divided into three sub-groups: cortical cataract, nuclear sclerosis and posterior subcapsular cataract. Colour contrast was measured before and after cataract operation. RESULTS: There were significant differences in peripheral colour contrast thresholds comparing the preoperative and postoperative results. This difference existed even in patients (n=19) with a pre-operative visual acuity > or = 0.5 (mean 0.6). The tritan axis was the one most affected by cataract. There was no significant difference between cataract sub-groups. Also, the central colour contrast sensitivity was affected by cataract. Again, the tritan axis was the most affected one. There was no significant difference between the cataract sub-groups. We also found large and significant differences in central colour contrast thresholds between normal subjects and postoperative values from the cataract group in all colour axes. The colour contrast sensitivity was poorer in pseudophakes than in normals. There was a difference between the three groups of different IOL material used (PMMA, acrylic and silicone). The difference was significant in the protan axis, the acrylic group having the best colour contrast sensitivity. CONCLUSION: Peripheral colour contrast sensitivity was affected by cataract, even when only moderately developed. This finding is of importance and should be considered when the method is used to study other eye diseases e.g. glaucoma. Central colour contrast sensitivity was also affected by cataract. The pseudophakes were found to have poorer colour contrast sensitivity than normals. The material in the IOL seemed to be of importance for colour contrast.

Acrylates↗
PubMed1995

Peripheral contrast sensitivity for dynamic sinusoidal gratings in early glaucoma.

Automated contrast thresholds were established for dynamic, 2 reversals per sec phase-shifted, sinusoidal gratings in a 5 degrees circular test field centred 7.5 degrees from the fixation point in six positions in the visual field in 16 patients (age 56-76 years) with clinically established (optic disc or nerve fibre layer damage) early glaucoma, without visual field defects. For reference, contrast thresholds were also obtained in 16 sex-matched and age-matched controls. For all three spatial frequencies, thresholds were raised in the glaucoma group (0.5 c/deg: p = 0.0034-0.041, 2 positions n.s.; 1.0 c/deg: p = 0.0093-0.049, 1 position n.s.; 2.0 c/deg: p = 0.0011-0.041, 1 position n.s.). Deficiencies did not correlate to glaucoma type (simplex vs capsular), intraocular pressure level at examination, visual acuity, or local therapy (beta-blockers vs miotics). In the glaucoma group, there was a general loss of contrast sensitivity in all six positions tested in the visual field, reflected in roughly similar threshold elevations. Losses appeared slightly greater in the lower hemi-field. Definite contrast threshold elevations from the early glaucomatous process were established in this group of glaucoma patients without visual field defects. However, the method was considered to be of less value in glaucoma detection for individual subjects, due to the large overlap in threshold values between glaucoma patients and controls.

Aged↗
PubMed1994

Normal human contrast sensitivity for static and dynamic sinusoidal gratings. A comparison between two automated threshold determination designs.

Contrast thresholds for static and dynamic (phase-shifted at 2 rps) sinusoidal gratings were established for seven spatial frequencies 0.5-32 c/deg. An HP-85 desktop computer ran an automated stimulus descending algorithm. Subjects reported stimulus presence by pressing a switch. Two stimulus presentation designs were used. In method 1, the screen was blanked to mean luminance between presentations, while in method 2 the pattern remained unchanged until the next contrast level was presented. Mean thresholds were calculated from three successive threshold passages using 2 dB steps. Fifty-nine volunteers from a military unit, mean age 20 years, participated in the study. Method 1 always gave lower thresholds with less variability. For static gratings, this was statistically significant at 0.5 and 16 c/deg (p < 0.01 and 0.05, respectively) and for dynamic gratings at all spatial frequencies except 32 c/deg (p < 0.1 for 0.5 and 16 c/deg, p < 0.001 for 1-8 c/deg). An accuracy index was calculated from two determinations at 4 c/deg. Method 1 gave higher indices for both static and dynamic patterns, although not statistically significant. However, method 1 was significantly more time consuming. Method 1 was considered the more reliable of the two contrast threshold determining designs.

Adolescent↗
PubMed1992

Superoxide dismutase in the anterior chamber and the vitreous of diabetic patients.

Total superoxide dismutase (SOD) activity was examined in the anterior humor of 32 diabetic patients and 34 nondiabetic controls during cataract extraction. Median age (95% confidence interval) was 77.5 yr (73.3-81.0) and 79.3 yr (76.0-83.2), respectively. The SOD activity also was examined in posterior vitreous sampled peroperatively in 10 diabetics with proliferative retinopathy and post-mortem in seven diabetic patients and 35 nondiabetic controls. Ages were 57.2 yr (35.0-73.9), 74.4 yr (40.7-83.6), and 73.8 yr (65.0-80.2), respectively. In nondiabetic patients, the total SOD activity was much lower in the anterior chamber, 9.9 U/ml (8.1-12.6), than in the posterior vitreous, 106.3 U/ml (range 65.6-119.0), P < 0.001. We found no difference between the SOD levels in the anterior chamber of nondiabetic controls and diabetic patients, who had 9.6 U/ml (7.6-13.7). The SOD activity in posterior vitreous in diabetic patients sampled peroperatively, 23.9 U/ml (8.9-39.2), P < 0.0001, and post-mortem, 39.5 U/ml (6.5-214.2), P < 0.04, was significantly lower than in the controls sampled post-mortem, 106.3 U/ml (65.6-119.0). Low levels of SOD in the anterior chamber may be involved in cataract development, in diabetic patients and nondiabetic controls. That diabetics had decreased SOD activity in the posterior vitreous points to a possible role of SOD in the complex process of diabetic retinopathy development.

Adult↗
PubMed1991

Long-term efficacy and safety of simvastatin alone and in combination therapy in treatment of hypercholesterolaemia.

The 3-years efficacy and safety of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor simvastatin (S) (previously called synvinolin or MK-733) has been studied in single and combined therapy with cholestyramine (C) in 48 hypercholesterolaemic patients. Plasma lipids, lipoproteins and apolipoproteins A-I and B, and blood safety tests (haematology, liver function, creatine phosphokinase (CPK), creatinine, blood glucose and thyroid function) were determined regularly throughout the study. Extensive ophthalmological examinations with particular focus on the lens were done before initiation of therapy and at every 6 months during drug treatment. Maximal reductions of mean plasma total cholesterol concentration (34% with S; 47% with S + C) and low-density lipoprotein (LDL)-cholesterol concentration (42% with S; 56% with S + C) were achieved after 4 weeks on full-dose therapy. During continued treatment, years 1 through 3, the reduction of mean plasma total cholesterol was 26-29% with S alone, and 31-41% with S + C. Significant reductions of plasma triglycerides (15-27%) and very low density lipoprotein (VLDL) triglycerides (10-27%) were achieved in the group treated with S as single therapy. In this group there was also a significant increase (10-14%) of high-density lipoprotein (HDL)-cholesterol. In liver aspartate (AST) and alanine (ALT) aminotransferases, as well as alkaline phosphatase (ALP), minor and variable, but usually transient, increases were seen. Repeated ophthalmological examinations did not demonstrate any drug-related side effects. It is concluded that simvastatin is a safe and efficient cholesterol-lowering drug for long-term therapy, both as a single drug and in combination with cholestyramine.

Adult↗
PubMed1990

Lens changes in matched normals and hyperlipidemic patients treated with simvastatin for 2 years.

Simvastatin, a potent blood lipid reducer, has been suspected of inducing cataract in dogs. Twenty-nine type II hyperlipidemic patients on simvastatin were followed over 2 years at half-year intervals. A parallel group of sex- and age-matched normolipidemics were followed over a half year. Patients and controls had similar nuclear and cortical lens opacities, and water clefts. Vacuole number did not differ significantly between right and left eyes, nor between nasal and temporal parts of the lenses. General vacuole index (total vacuole number in a patient) for left eyes was analysed further. Controls showed significantly higher indices than patients, for no obvious reason. Indices for controls increased significantly over the half-year test period, and among patients over each half-year interval. The speed of this increase did not differ significantly from that of the controls. Furthermore, the increase was judged to be clinically insignificant. No deleterious effect of simvastatin on the lens could be established.

Adult↗
PubMed1986

Two years' clinical experience with the preferential looking technique for visual acuity determination in infants and young children.

Two years' experience with a preferential looking technique for visual acuity determination was evaluated. Ninety-three patients were tested during this period, but selected groups (34 patients) were reported on earlier. In 59 patients aged 2 months to 13.75 years 131 testing procedures were performed. Diagnostic groups included uncomplicated strabismus (n = 26), strabismus combined with neurological disturbances (n = 16), neurological disturbances alone (n = 11) and other ocular diseases (n = 6). In addition, several of the children were mentally retarded. In 52 of the 59 patients in this study valuable results were obtained, while no useful information could be gathered from the remaining 7 patients. The findings influenced therapy strategies in 24 patients, and subsequent testing reflected therapeutic effectiveness. The test was successful in 7 of 8 patients referred from other clinics for estimation of visual function. Although established acuity thresholds should be regarded as conservative estimates, and not directly comparable to Snellen letter acuity notations, the preferential looking technique proved to be quite valuable in a paediatric ophthalmology unit. Main indications were amblyopia detection, control of therapeutic measures in strabismics, including pre-operative evaluation, and estimation of visual capacity in children with psychomotor retardation.

Age Factors↗
PubMed1986

Endothelial cell density after penetrating keratoplasty using long-time banked donor material after long distance transportation (Denmark-Sweden).

Central corneal cell density was evaluated from photographs obtained by a clinical non-contact specular microscope (Zeiss) in 48 patients at a mean post-operative time of 7 1/2 months after penetrating keratoplasty for a number of different causes, keratoconus being the most frequent indication. Cell density decrease on this occasion was compared to pre-operative data from the Eye Bank in Arhus, Denmark, which supplied corneo-scleral preparations transported by ferry and train to Linköping, Sweden. A mean decrease in cell density of 4.4% was recorded during bank time (11-27 days). A further mean decrease from final preparation to post-operative photography of 36.5% was found. Mean total cell density decrease amounted to 39.4%, which compares well with results found in other studies. Among several factors studied, the only one associated with significantly (P less than 0.02) greater cell density decrease than other factors was long post-mortal time periods (death to bank preparation). Mean final endothelial cell density was 1899 cells/mm2, which should correspond to a good functional reserve of donor endothelium. Neither the long bank time, nor the transportation seemed to be of major importance with respect to donor material quality. Foreign material supply can be a good solution to local corneal shortage.

Cell Count↗
PubMed1985

Central contrast sensitivity tests in the detection of early glaucoma.

The value of contrast sensitivity testing in glaucoma is still unsettled. To determine their value in screening for glaucoma 2 methods were applied to glaucoma patients (12 simplex, 9 pseudo-exfoliative). The techniques included an oscilloscope method generating centrally presented gratings and the Arden grating test. Results obtained were compared to those of age-matched normals (n = 11, one eye randomly selected). Unacceptable false negative rates were found for both methods, as well as a high false positive rate (2/11 normals) with the Arden grating test, confirming findings in earlier studies. No correlation could be demonstrated between contrast sensitivity deficits and visual field disturbance, glaucoma type or duration. It was concluded that central contrast sensitivity for static gratings is unable to reliably indicate the presence or absence of early glaucoma.

Aged↗
PubMed1985

Central and peripheral contrast sensitivity for static and dynamic sinusoidal gratings in glaucoma.

Contrast sensitivity testing in glaucoma patients was extended from central, static patterns to include peripheral areas and dynamic gratings. The results were compared with age-matched normals in visuograms, and sensitivity defects were correlated to the location of visual field defects. Tested spatial frequencies included 0.3, 0.5 1, 2 and 4 c/d. Definite sensitivity losses for all spatial frequencies were found for dynamic patterns in testing positions located 10 degrees eccentrically above and below fixation. For static patterns in the periphery sensitivity was reduced only for medium spatial frequencies. For central viewing, reduced sensitivity was found with dynamic medium spatial frequencies only. No centrally presented static gratings were of subnormal sensitivity. Dynamic patterns in the periphery were superior to other combinations regarding the capacity for indicating the presence of glaucomatous influence. Peripheral sensitivity losses also occurred when perimetric disturbances were located outside the area tested in the same hemi-field. Depressed sensitivity was observed even in hemifields with normal/near-normal perimetric fields. These findings might be indicative of an early glaucomatous impairment. It thus seems that testing peripheral dynamic contrast sensitivity might be a potentially valuable method for glaucoma screening.

Aged↗
PubMed1983

Prizidilol, a combined vasodilatory and beta-adrenoceptor blocking drug, in primary hypertension. A long-term efficacy, tolerance and pharmacokinetic study.

After an initial placebo period of four weeks 24 patients with primary hypertension were treated with prizidilol, a hydrazinopyridazine derivative with combined vasodilator and non-selective beta-adrenoceptor blocking actions, for a dose titration period of 14 weeks. Prizidilol 200 to 800 mg was given once daily to achieve a target supine diastolic blood pressure (BP) less than 90 mmHg. Supine and standing BP recorded 24-27 h after drug intake decreased from 172 +/- 17/106 +/- 6 mmHg (mean +/- SD) and 167 +/- 18/111 +/- 8 mmHg, respectively, after placebo to 159 +/- 16/99 +/- 8 and 154 +/- 18/101 +/- 9 mmHg after active treatment for six weeks (mean dose 447 mg), and to 154 +/- 16/97 +/- 7 and 148 +/- 14/97 +/- 7 mmHg after treatment for 14 weeks (mean dose 687 mg/day). A slight reduction in HR was seen after treatment for six weeks and in plasma renin activity and urinary methoxycatecholamine excretion after treatment for 14 weeks. A sustained decrease in BP was observed for 10 h after prizidilol 800 mg (n = 9), with a maximum antihypertensive effect (mean reduction in supine BP 33/18 mmHg) 2.5 h after dosing, which coincided with the mean peak plasma concentration. The plasma elimination half-life of the drug was 3.9 h (range 2.0-8.9 h). Changing to a twice daily regimen in 17 patients (mean daily dose 748 mg at six months) did not produce any further reduction in the BP (recorded 12-15 h after dosing) as compared to the once daily regimen at 14 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylation↗
PubMed1983

Central and peripheral normal contrast sensitivity for static and dynamic sinusoidal gratings.

Contrast sensitivity for moving and stationary sine grating patterns was determined in central and peripheral parts of the visual field. The method was primarily developed as a possible screening procedure for visual defects in glaucoma. Contrast sensitivity to moving patterns seemed maximal both in central and in 10 degrees of eccentric viewing for square wave reversals of temporal frequencies 0.5-5 Hz. We selected 2Hz for the clinical procedure. Further, we have determined normal central and peripheral contrast sensitivity in 10 subjects 61-71 years-old, to serve as a basis for the glaucoma studies. We used this age group since glaucoma mainly affects elderly people. We confirmed that contrast sensitivity was higher for dynamic than for static presentation of gratings of low spatial frequencies (below 1 c/d) both centrally and peripherally. For patterns of medium or high spatial frequencies, dynamic and static stimuli were equally detectable. The absolute level of contrast sensitivity was higher centrally than peripherally in the interval 0.3-4 c/d. The lower visual hemifield exhibited greater sensitivity, for both static and dynamic gratings, than the upper one.

Adult↗
PubMed1983

Effects of amblyopia therapy on contrast sensitivity as reflected in the visuogram.

A quantitative evaluation of the Cambridge amblyopia treatment on contrast sensitivity was performed for 2 groups, one comprising 11 children with strabismic amblyopia (S) and another of 10 children with combined strabismic and anisometropic amblyopia (S & A). Contrast sensitivity deficits were expressed in dB CSL (Contrast Seeing Level) in relation to normal sensitivity of the same age group and represented in the form of visuograms. Mean contrast sensitivity losses in dB CSL were estimated within the low, medium and high spatial frequency ranges, as well as over the total frequency band. On an average S & A amblyopia was found to affect contrast sensitivity of all spatial frequencies, while S amblyopia affected mainly the higher frequency band, but to a smaller extent. After therapy average contrast sensitivity improved for both S and S & A groups, and reached the same, subnormal levels. The relation between highest resolvable spatial frequency (according to our method) and Snellen acuity was different for the 2 amblyopia groups. No correlation was found between improvements in contrast sensitivity and Snellen acuity, which is why both parameters should be estimated.

Adolescent↗
PubMed1981

Effects of grating stimulation on visual acuity in amblyopia.

Thirty-one children with amblyopia were treated with CAM vision stimulation. Twenty-one of them had previously been treated with conventional methods but failed to improve further. The conventional therapy was continued during and after CAM. Grating stimulation was the first treatment attempted for the rest of the children. Most children in both groups showed improved distance visual acuity after CAM-treatment and no one suffered a loss. The average visual acuity improvement was the same in both groups of children and did not vary with age. The improvement amounted to about 50% of the visual acuity before CAM, irrespective of the pre-treatment acuity level. We conclude that CAM-stimulation can be useful in cases where occlusion or other amblyopia treatment has failed, but that some form of treatment must be continued if visual acuity is to be maintained after the CAM-treatment period.

Adolescent↗
PubMed1981

Picture simulation of contrast sensitivity in organic and functional amblyopia.

We have tried to illustrate some contrast sensitivity defects by picture simulation. We have used data obtained from 2 patients: a woman with optic nerve lesion (Snellen VA 0.5) and a 7.5-year-old boy with anisometropic amblyopia (VA 0.6). The optic nerve lesion was represented by profound contrast sensitivity loss for all spatial frequencies, while the anisometropic eye showed loss only at high spatial frequencies. A positive picture was decomposed into 1.25 X 10(6) pixels (picture elements), using a drum scanner. In a computer each spatial frequency component of the picture was multiplied by the ratio between the patient sensitivity value and that of an age-matched reference group and a modified image was processed. The pictures illustrate the poor image quality that is associated with general contrast sensitivity loss, even when Snellen visual acuity is only moderately impaired.

Amblyopia↗