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Biomedical subjects

K Naeser

Publications and source records attributed to K Naeser.

At least 19 recordsLinked to original sources
PubMed1999

Mortality and causes of mortality among cataract-extracted patients. A 10-year follow-up.

PURPOSE: The purpose of this study was to compare the mortality among patients undergoing intracapsular cataract extraction to the mortality in a gender-and age-identical Danish reference population, and to compare the patients' primary causes of death to those in the general population. MATERIALS AND METHODS: We reviewed medical records of patients undergoing ICCE from January 1st 1984 to December 31st 1986 at the Department of Ophthalmology, Aalborg Hospital, Denmark. Information on the deaths of these patients was obtained from the Danish National Population Register. Information on mortality in Denmark was obtained from published statistics. RESULTS: We found an increased mortality among the patients with cataract with an SMR (standard mortality rate) of 1.12 (95% confidence interval 1.02-1.23). The slightly increased mortality was observed for both men and women and for all examined causes of death. CONCLUSION: The slightly increased mortality among patients with cataract may indicate a general deterioration of health for these patients.

Age Distribution↗
PubMed1999

Persistent corneal oedema following ICCE. Influence of IOL type.

PURPOSE: To examine the frequency of persistent corneal oedema following intracapsular cataract extraction (ICCE). To examine whether the type of intraocular lens has any influence on persistent corneal oedema following ICCE. METHODS: A retrospective study of 1041 consecutive ICCE operations followed for at least eight years. The cumulative incidence of persistent corneal oedema was calculated for the whole group and compared to the incidence in subgroups defined by type of intraocular lens. RESULTS: The cumulative incidence of persistent corneal oedema following ICCE was 2.3% for the whole group. The highest incidence (10.3%) was found in the group of patients, who received a 3-M style 77 anterior chamber lens while the lowest incidence (1.0%) were found among patients receiving a Choyce anterior chamber lens. Compared to this, the patients who received no intraocular lens showed a frequency of persistent corneal oedema of 1.4%. Among the patients who developed persistent corneal oedema the number of re-operations was higher (27.3%) compared to the patients who did not develop persistent corneal oedema (4.4%). The frequency of preoperative dystrophy was the same whether or not the patients developed persistent corneal oedema. There were no difference in gender, age or other pre-operative data between the two groups. CONCLUSION: After ICCE 2.3% developed persistent corneal oedema. There was a significant difference between the frequencies of persistent corneal oedema depending on the type of intraocular lens from 1.0% in eyes receiving a Choyce anterior chamber lens to 10.3% in eyes receiving a semi-flexible 3-M style 77 anterior chamber lens.

Aged↗
PubMed1998

Retinal detachment following intracapsular cataract extraction. A 10-year follow-up study.

PURPOSE: To examine the incidence of and risk factors for retinal detachment during a 10-year follow-up on intracapsular cataract extraction (ICCE). METHODS: Retrospective analysis of medical records of 1041 eyes operated on with ICCE in the years 1984-86. A complete follow-up was achieved, and actuarial methods were used in the risk assessment. The risk time averaged 82 months. RESULTS: Twenty-two (2.1%) eyes developed retinal detachment; half of the cases occurred during the first postoperative year, but new cases emerged throughout the period. The cumulative incidence of RD amounted to 2.8%; 95% confidence interval: 1.5-4.2%. Multivariate Cox regression analysis identified younger age at surgery (relative risk for each 10-year increase in age=0.6; 95% confidence interval: 0.39-0.95) and male gender (relative risk=2.5; 95% confidence interval 1.04-6.04) as significant risk factors for RD. Eleven eyes, 50% of eyes with RD and 1% of the total number of eyes, lost useful vision in spite of retinal surgery. CONCLUSION: Even though the risk for both RD and an unfavourable result following retinal surgery may be smaller using contemporary surgical techniques, the present study indicates a substantial morbidity following cataract surgery, when a sufficiently long observation period is considered.

Age Distribution↗
PubMed1997

Intraocular lens power formula based on vergence calculation and lens design.

PURPOSE: To present a new method of intraocular lens (IOL) power calculation that takes into account the power-dependent variation in lens design. SETTING: Department of Ophthalmology, Aalborg, Denmark. METHODS: Information on exact IOL design is derived from the manufacturers' cutting cards. These data were built into an IOL calculation formula based on exact ray tracing and vergence calculation. All algorithms are demonstrated. RESULTS: The method is optically correct as all refractive surfaces are characterized with respect to both position and refractive power. In simulation models, the Naeser and the Holladay formulas performed similarly, while the SRK/T formula predicted higher postoperative refractions for low-power IOLs. CONCLUSION: It is possible to incorporate the exact IOL design into an IOL power calculation formula. Theoretically, the Naeser formula should increase the accuracy of IOL power calculation; however, this has yet to be proved from empirical data. The formula provides an advantage in analysis of postoperative pseudophakia for experimental/scientific purposes because all intraocular distances and powers may be measured or calculated.

Algorithms↗
PubMed1997

Experience with a broth culture technique for diagnosis of bacterial keratitis.

PURPOSE: To determine if a broth culture technique is a practical means for bacteriological investigation of keratitis. MATERIAL AND METHODS: Twenty-seven eyes of 27 patients with a clinical diagnosis of bacterial keratitis were included in a prospective and non-comparative study at a Danish referral hospital. A corneal scrape was inoculated directly into broth medium which was transferred to the diagnostic laboratory for incubation and subculture. RESULTS: Culture was negative in 4 patients, and 19 of the remaining 23 patients had a pure growth of either Pseudomonas aeruginosa (n = 8), Staphylococcus aureus (n = 2), Streptococcus pneumoniae (n = 2), Haemophilus influenzae biotype III (n = 1), Moraxella species (n = 1), Corynebacterium species (n = 1), or coagulase-negative staphylococci (n = 4). In 4 patients there was a mixed gram-positive growth. There was no association between microbiological findings and previous topical antibiotic therapy. Contamination and lack of quantitative assessment of growth proved not to be a problem. CONCLUSIONS: By broth culture technique we identified a definite pathogen (P. aeruginosa, S. aureus or S. pneumoniae) in 44% of patients (95% binomial confidence limits: 25-65%). The technique may replace the standard technique of direct plate culture under circumstances where it is difficult to keep a supply of fresh media or transport inoculated plates.

Adult↗
PubMed1996

Indications for cataract surgery in a Danish county 1980 and 1990.

From 1980 to 1990 the number of cataract extractions in our department increased from 268 to 827, i.e. 209% within the same referral area. A review was made to see if the indications for cataract extraction had changed in that period. The increase in frequency of cataract extractions was statistically significant in all age groups except males aged 60-69. The increase was most noticeable in the older age groups. Preoperative visual activities were moderately higher in 1990 compared with 1980. The frequency of second eye surgery did not change in the period. Females had in 1980 as in 1990 a higher frequency of cataract extractions than males in all age groups > 60 years.

Adult↗
PubMed1995

Retinal detachment following intracapsular and extracapsular cataract extraction.

In 1984, our ophthalmology department switched from intracapsular cataract extraction (ICCE) to extracapsular cataract extraction (ECCE). We reviewed the postoperative incidence of retinal detachment (RD) in two consecutive series: (1) 604 eyes operated on by ICCE from 1982 to 1983 and (2) 1726 eyes operated on by ECCE from 1985 to 1986. Follow-up averaged 39 months in both groups. The RD incidence was 1.30% after ICCE and 0.41% after ECCE, a statistically significant difference. In both groups, the risk of RD was high for patients less than 70 years of age at the time of surgery but minimal for patients older than 70 years. The proportion of younger patients was significantly higher in the ICCE group (29.5%) than in the ECCE group (23.2%). When the data were stratified by age and the difference in age composition adjusted for statistically, the difference between the two groups in the incidence of postoperative RD was less pronounced. We conclude that although not significant at the 5% level after adjusting for age distribution, our results suggest a decreased risk of RD with ECCE.

Aged↗
PubMed1995

Refraction and anterior chamber depth before and after neodymium: YAG laser treatment for posterior capsule opacification in pseudophakic eyes: a prospective study.

Anterior chamber depth and refraction were evaluated in 52 pseudophakic eyes before and about one month after neodymium: YAG laser capsulotomy for posterior capsule opacification. External anterior chamber depth averaged 4.06 mm before and 4.07 mm after laser treatment, a statistically insignificant change. Mean spherical equivalent refraction before laser treatment, estimated from the prescription of spectacles, was 0.30 diopters (D). Mean subjective refraction after laser treatment was 0.24 D. The difference was not significant. Mean capsulotomy opening diameter increased from 3.44 mm +/- 0.61 mm (+/- SD) immediately after the laser treatment to 3.67 mm +/- 0.61 mm one month later. The increase was statistically significant. Intraocular lens position and spherical equivalent refraction did not change after the YAG laser capsulotomy, despite a significant increase in area of the capsulotomy opening.

Adult↗
PubMed1995

Intraocular pressure seven years after extracapsular cataract extraction and sulcus implantation of a posterior chamber intraocular lens.

Seven years after extracapsular cataract extraction (ECCE) and sulcus implantation of a posterior chamber intraocular lens, we measured the intraocular pressure (IOP) in 28 eyes of 28 patients. The results were compared with the preoperative IOP and with the postoperative IOP at four months and 2 1/2 years. The mean IOP value seven years after surgery was 1.3 mm Hg lower than the preoperative mean value. No significant difference was found among the values at four months, 2 1/2 years, and seven years. One patient experienced a marked rise in IOP between 2 1/2 years and seven years and was excluded from the calculations. However, we could not tell whether it was a consequence of the cataract surgery. In this study, we found that IOP stabilized at a postoperative level that was significantly lower than the preoperative value and has remained there for seven years.

Aged↗
PubMed1994

Quantitative assessment of corneal astigmatic surgery: expanding the polar values concept.

The purpose of astigmatic corneal surgery is to flatten the steeper meridian of the preoperative cylinder, to steepen the flatter meridian, or both. Therefore, it may be useful to quantitate the surgical effect by calculating the equivalent dioptric value of the postoperative cylinder in these principal meridians. In this study, the dioptric value projected on the preoperatively steeper meridian is termed the with-the-power (WTP) component, the portion projected on the flatter meridian, the against-the-power (ATP) component. Consider a preoperative net astigmatism of the power N in the meridian a. After astigmatic corneal surgery, the postoperative corneal cylinder is M in the meridian b. For the postoperative cylinder, the WTP component = M x sin2([b + 90]-a). The ATP component = M x cos2([b + 90]-a). The astigmatic polar value is defined as the difference between these magnitudes: AKP = M x (sin2[(b + 90)-a] - cos2[(b + 90)-a]). By calculating the astigmatic polar value, the surgeon immediately knows the outcome of the surgical procedure (i.e., whether the preoperative astigmatism has been undercorrected, overcorrected, or perfectly corrected). We describe the theory behind this new formula and discuss its applications and limitations.

Astigmatism↗
PubMed1993

Calculation of the thickness of an intraocular lens.

Lens manufacturers do not usually supply information about the central thickness of an intraocular lens optic. This paper describes a method to calculate the central lens thickness from variables normally supplied by the manufacturer, i.e., the total lens power in situ, the edge thickness, the optic diameter, and some knowledge of the optic architecture. The formulas are universal and valid for any lens, regardless of lens design and material. There is a correlation between calculated values of optic thickness and values supplied by manufacturers. Individually estimated lens thickness may increase the accuracy of intraocular lens power calculation, pseudophakic anterior chamber depth estimation, and pseudophakic axial length calculation.

Anterior Chamber↗
PubMed1993

Epidemiology of retinal detachment following extracapsular cataract extraction: a follow-up study with an analysis of risk factors.

We reviewed the medical records of 1,726 eyes consecutively operated on with extracapsular cataract extraction to examine the incidence of and the risk factors for retinal detachment (RD). In Denmark, both diagnoses and deaths are registered centrally; therefore, a complete follow-up was achieved in each case and actuarial statistical methods were used in the risk assessment. Seven eyes (0.41%) developed RD and 345 eyes (20.0%) had YAG-laser capsulotomy in the observation period, which averaged 39 months. We identified the following risk factors for RD: age less than 70 years at the time of surgery, intraoperative complications, axial length > or = 25 mm. Nonsignificant factors included male gender and postoperative complications. One eye (0.29%) developed RD following YAG-laser capsulotomy. We concluded that the high risk of RD is concentrated in a small group of myopic patients who have cataract surgery when they are less than 70 years of age. Our results do not suggest a causal relationship between YAG-laser capsulotomy and subsequent RD.

Adult↗
PubMed1993

Retinal detachment following intracapsular and extracapsular cataract extraction. A comparative, retrospective follow-up study.

In a retrospective study we reviewed the post-operative incidence of retinal detachment in a consecutive series of 762 eyes operated on with intracapsular cataract extraction and a consecutive series of 1351 eyes operated on with extracapsular cataract extraction. Follow-up time was 2 1/2-4 1/2 years in both series. The incidence of retinal detachment was 0.79% after intracapsular cataract extraction and 0.44% after extracapsular cataract extraction. The difference was not statistically significant. Age below 70 years was not statistically significantly correlated to retinal detachment.

Adolescent↗
PubMed1991

Intraocular pressure 2 1/2 years after extracapsular cataract extraction and sulcus implantation of posterior chamber intraocular lens.

The intraocular pressure in 50 eyes of 50 patients was measured 2 1/2 years after planned extracapsular cataract extraction with intended implantation of a posterior chamber lens in the ciliary sulcus. The results were compared to the preoperative values, and the pressure observed after 4 months. Although a significant elevation was found from the fourth month (P = 0.015), the intraocular pressure at 2 1/2 years was found to be significantly lower than the preoperative value (P = 0.002). No significant difference was found in two subgroups in which transillumination defects in the iris or pigment in the lower anterior chamber angle was present.

Aged↗