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Biomedical subjects

E Haaskjold

Publications and source records attributed to E Haaskjold.

At least 19 recordsLinked to original sources

A previous abrasion in the contralateral eye influences the cell kinetics during healing of a central corneal abrasion.

PURPOSE: To study the influence of a previous erosion in the fellow eye on the proliferative response during healing of a central corneal erosion. METHODS: A corneal abrasion was made on the right eye of 20 rats. After 1 week a corneal erosion was made in the left eye of the pre-treated animals and in 20 previously untreated animals. Cell kinetic methods were used to estimate the labelling index (LI) and the mitotic rate (MR) after 1, 2, 4, 6 and 12 days. RESULTS: After 24 hours the corneal erosions were covered by epithelial cells in 3 of 4 animals in both groups. The LI and the MR were significantly higher in the pre-treated group on the 2nd day after erosion. CONCLUSIONS: The proliferation measured by LI and MR was increased when an abrasion was made in the contralateral eye 1 week earlier. This might explain the faster healing rate of the second eye reported by other authors (Rask et al. 1996). The healing process in the cornea is modulated by systemic influence.

Animals↗

Phacoemulsification in eyes with pseudoexfoliation.

PURPOSE: To compare intraoperative and postoperative complications in eyes with and without pseudoexfoliation having cataract surgery by phacoemulsification. SETTING: Department of Ophthalmology, National Hospital, Oslo, Norway. METHODS: Of 1152 consecutive phacoemulsification procedures, 164 cases with pseudoexfoliation (Group 1) and 916 cases without (Group 2) were followed for 4 months after cataract surgery in a prospective study. Of all cataract operations performed during that time, 96.2% were phacoemulsification procedures; 90.4 and 97.4% in eyes with and without pseudoexfoliation, respectively (P < .0005). RESULTS: The frequency of capsular/zonular tear or vitreous loss was 9.6 and 3.7% in Groups 1 and 2, respectively (P = .0002). A visual acuity of 0.5 or better was achieved in 86.5% of eyes in Group 1 and 92.4% in Group 2 (P = .02). There were no statistically significant between-group differences in the frequency of a postoperative inflammatory response 1 day (6.7 versus 4.4%), 1 week (2.4 versus 1.6%), or 4 months (1.8 versus 0.9%) postoperatively. CONCLUSION: Phacoemulsification was safe in most eyes with pseudoexfoliation even though significantly more complications occurred intraoperatively in these eyes. The low frequency of an inflammatory response indicates that the presence of pseudoexfoliation does not significantly increase the risk of inflammation.

Adolescent↗

Contrast sensitivity after implantation of diffractive bifocal and monofocal intraocular lenses.

PURPOSE: To compare contrast sensitivity (CS) after implantation of a diffractive bifocal intraocular lens (IOL) and a monofocal IOL of similar design. SETTING: Seven European centers. METHODS: In this randomized, prospective study, CS was tested 5 months after cataract and IOL implantation surgery in 115 patients with a diffractive bifocal IOL and 106 patients with a monofocal IOL. It was also tested in a subgroup of 38 patients who had bilateral implantation of a diffractive bifocal IOL. Contrast sensitivity was tested using the Vision Contrast Test System (VCTS). RESULTS: In patients with a best corrected visual acuity (BCVA) of 1.0 or better, the CS at all spatial frequencies (1.5 to 18 cycles/degree), both at distance and near, was slightly lower in the bifocal IOL group than in the monofocal group. Mean values were within the normal range. In patients with a BCVA of less than 1.0, the CS was lower and the difference between the bifocal and monofocal groups was less. In patients with bilateral bifocal IOLs, CS was better when tested bilaterally than when testing the better eye alone. Pupil size affected the results to a small degree. Contrast sensitivity appeared to improve over time after implantation of a diffractive bifocal IOL. CONCLUSIONS: In patients with cataract and no other eye pathology, the diffractive bifocal IOL with slightly reduce the CS at all spatial frequencies. In those with reduced visual acuity after cataract surgery, CS will be reduced accordingly. In this situation, the reduction from the diffractive bifocal optic would be minor.

Aged↗

Epithelial wound healing of the rat cornea after excimer laser ablation.

Rats with excimer corneal ablations (ArF 193 nm, 228 pulses, diameter 3,5 mm, 17.3 mJ per pulse, depth about 1/2 of corneal thickness) in one eye were killed 1, 2, 4, 6 and 13 days after treatment. The other eye served as control. The cell number per microscopic vision field, the labelling index (LI) and the mitotic rate (MR) were calculated for the peripheral, midperipheral and central areas of the corneal epithelium. The cell number showed a uniform depression in the remaining corneal epithelium at Day 1, normalizing from the centre to the periphery. The LI was only significantly increased at Day 1, while the MR was statistically significantly increased peripherally at Day 2 and in all areas at Day 6. However, when the corneal epithelium was evaluated as a whole, the MR was significantly increased at days 1, 2 and 6. The proliferative response of the epithelium was very homogenous irregardless of the distance to the original lesion. Both the migratory and the proliferative phases of the healing process seemed to be delayed when compared to the healing of pure epithelial wounds. However, the initiation of an increase in DNA synthesis seems not to be delayed, indicating that it is primarily the G2 phase that has been prolonged with this ablation procedure. The stromal thickness was increased from about one half of the normal values immediately after the treatment to above normal values at Day 4, thereafter decreasing to normal values at Day 13. Thus, the regenerative ability of the stroma is more pronounced in rats than in humans, but also in humans regeneration of the stroma can possibly explain the regression of the myopic shift seen some time after excimer laser treatment.

Animals↗

UVB-induced formation of (6-4) photoproducts in the rat corneal epithelium.

The induction of DNA photoproducts in rat corneal epithelium was studied after in vivo exposure to different doses of ultraviolet B light at 297 nm. Affinity-purified antibodies with a major specificity against UV-induced (6-4) photoproducts were used. The results indicate a dose dependent formation of (6-4) photoproducts. Even a minimal erythema dose (25 mJ/cm2) produced (6-4) photoproducts, demonstrating that DNA damage occurs in corneal tissue following exposure to biologically relevant doses of UVB light.

Animals↗

Accuracy of IOL calculation in cataract surgery.

The accuracy of IOL calculation using the SRK II formula was studied in 515 cataract extractions with posterior chamber IOLs. All excessively myopic patients (8 patients) and those where we had predicted an emmetropic postoperative result, from a consecutive series of 994 patients, were included. Preoperatively the patients were divided into different groups according to their refractive status and the mean postoperative refraction was calculated in each group. The mean postoperative refraction increased almost linearly with increasing myopic status. The emmetropic group achieved a mean postoperative refraction of -0.6 D, whilst in the most myopic group mean refraction was -1.8 D. We believe that the SRK II formula is inaccurate for myopic eyes, and that new formulas are needed, taking into account all those factors that make up the dioptric power of an eye.

Aged↗

Comparison of a diffractive bifocal and a monofocal intraocular lens.

PURPOSE: To compare a Pharmacia diffractive bifocal intraocular lens (IOL) with a monofocal lens of the same design without the diffractive grating. SETTING: Multicenter study. METHODS: This randomized, prospective study comprised 70 patients with a monofocal IOL and 79 with a diffractive bifocal IOL. Follow-up was 5 to 6 months. Near and distance visual acuities, contract sensitivity, patient satisfaction, and spectacle use were evaluated. RESULTS: All patients achieved a best corrected visual acuity of 0.5 or better; 80% in the monofocal and 71% in the bifocal group had a best corrected visual acuity of 1.0 or better. Without correction, 93% of the bifocal and 9% of the monofocal group could read J3 or better. With distance correction, 99% and 4%, respectively, could read J3 or better. Contrast sensitivity was slightly lower in the bifocal group at distance and near for all spatial frequencies. In the bifocal group, 46% never used spectacles for near tasks. Overall satisfaction was rated good by 86% of the monofocal and 85% of the bifocal group. CONCLUSIONS: The diffractive bifocal IOL performed well at distance and near. Patients who no longer require spectacles will benefit significantly from a bifocal IOL, but many with a bifocal IOL in one eye will require spectacles for the fellow eye.

Aged↗

Regeneration of rat corneal epithelium is delayed by the inhibitory epidermal pentapeptide (EPP).

The effect of the inhibitory epidermal pentapeptide (EPP) on regeneration of rat corneal epithelium was studied over a 24-h period after removal of the central part of the corneal epithelium by means of n-heptanol and scraping. Both unphosphorylated and phosphorylated EPP inhibited the mitotic rate and the formation of new cells to the same extent. Thus, the mitosis inhibitor that originally was isolated from mouse epidermis, acts even on the ectodermally derived corneal epithelial cells.

Alcohols↗

Causes of decreased visual acuity after cataract extraction.

We analyzed a consecutive series of cataract extractions to determine the causes of unsuccessful results. Our criterion was a decrease in visual acuity from the preoperative measurement. Fourteen of 1237 eyes met this criterion. In three of the 14, visual acuity was decreased by more than two Snellen lines. Vitreous loss occurred in seven of the eyes. In six of these, cystoid macular edema developed. The reasons for reduced visual acuity were cystoid macular edema (eight eyes), an aggravation of age-related maculopathy (three eyes), and vitreous hemorrhage and herpetic keratitis (one eye each). A branch vein occlusion caused macular edema and vitreous hemorrhage in one eye. From this data, we recognize the importance of avoiding vitreous loss. If it does occur, we recommend that meticulous anterior vitrectomy be performed, with as little manipulation as possible.

Aged↗

Early cell kinetic effects of some drugs on the rat corneal and conjunctival epithelia.

The early cell kinetic response in the rat corneal and conjunctival epithelia was studied after a single topical application of dipivefrine, adrenaline and timolol with and without benzalkonium chloride. Benzalkonium chloride alone in different concentrations, 0.004%, 0.01%, 0.02% and 0.04%, respectively, was also evaluated. The stathmokinetic method and the tritiated thymidine technique were used to estimate the mitotic rate and the labelling index. Dipivefrine (Propine) gave a significant depression of the mitotic rate almost to the same extent as adrenaline in the corneal epithelium, whereas no changes were found in the limbal area and in the conjunctiva. Timolol (Oftan) with or without benzalkonium chloride, and benzalkonium chloride in different concentrations gave no obvious changes of the mitotic rate. No distinct drug effects on the labelling index were observed.

Animals↗

Use of collagen shields in cataract surgery.

A randomized, prospective, multicenter study evaluated the efficacy and safety of using collagen shields to deliver drugs after cataract surgery. Collagen shields saturated with an antibiotic and a steroid were placed in 90 eyes postoperatively. A control group of 93 eyes received the same drugs through a peribulbar/retrobulbar injection. One day after surgery, the shield group had significantly less corneal edema, conjunctival hemorrhaging, and postoperative pain and fewer corneal opacities. All symptoms except the conjunctival hemorrhaging disappeared by day seven. Our study suggests that using collagen shields for drug delivery after cataract surgery decreases tissue damage and increases patient comfort without adverse side effects.

Adult↗

Risk factors for an inflammatory response after extracapsular cataract extraction and posterior chamber IOL.

Risk factors for developing an inflammatory response after extracapsular cataract extraction with implantation of posterior chamber IOL have been studied. Out of 1154 cases included in the study, an inflammatory response was encountered in 63 eyes (5.5%). The inflammatory response was defined as increased cellular flare and/or as a fibrinous reaction during a follow-up of 4 months. Thirteen of the 63 eyes (20.6%) developed cellular precipitates, and posterior synechias were seen in 34 of these eyes (54.0%). Among 10 pre- and 10 peroperative putative risk factors analyzed in a logistic regression model, 5 variables had a statistically significant influence on the probability of developing postoperative inflammation; 1) Uveitis in history (p = 0.0001), 2) Pseudo-exfoliation syndrome (p = 0.0224), 3) Inability to obtain adequate mydriasis at the start of surgery (p < 0.0001), 4) Problems with IOL implantation (p = 0.0111) and 5) Pigment effusion during surgery (p = 0.0258).

Aged↗

Cell kinetics of conjunctival and corneal epithelium during regeneration of different-sized corneal epithelial defects.

Rats with small (diam. 1.7 mm), medium sized (diam. 3.5 mm) or large (diam. 5.5 mm) corneal epithelial erosions in one eye were killed 1, 2 or 4 days after the injury. The proliferative response was evaluated by measuring the labelling index and the mitotic rate in the corneal epithelium and in the adjacent conjunctiva. The small erosions triggered a proliferative response in the cornea only with the maximum response occurring midperipherally. The medium sized erosions induced a higher and more extensive response in the cornea and also a slight increase of the labelling index in the limbal area. The large erosions induced an even more pronounced response in the peripheral cornea and an increase both of the labelling index and the mitotic rate well beyond the limbal part of the conjunctiva. It is concluded that the magnitude and the extent both of the conjunctival and the corneal regenerative response to a corneal abrasion is correlated to the size of the corneal defect. Temporary reduction in the conjunctival epithelial cell number shows that both cells in the limbal and the extralimbal conjunctiva migrate centripetally during healing of large corneal wounds. It is suggested that the stem cell theory should be modified. The limbal area is probably an area in which conjunctival epithelial cells or conjunctiva-derivated cells transform or differentiate to corneal epithelial cells.

Animals↗

Extracapsular cataract extraction in eyes previously operated for glaucoma.

Extracapsular cataract extraction with IOL implantation was performed in 32 consecutive cases of glaucomatous eyes which previously had undergone trabeculectomy (group A). The only complication seen during surgery was one tear in the posterior capsule. The mean IOP on postoperative day 1 was 17.7 +/- 7.9 mmHg. After extracapsular cataract extraction in 68 glaucomatous eyes with no previous surgery (group B) the corresponding mean IOP was 21.7 +/- 7.5 mmHg (p = 0.015). However, the mean preoperative IOP level was lower in group A (group A: 14.3 +/- 4.0 mmHg, group B: 17.1 +/- 4.3 mmHg), so the increase in IOP was not significantly different in the two groups. In group A, 15.6% of the eyes had an IOP elevation exceeding 24 mmHg, compared to 30.9% of the eyes in group B. Four months postoperatively, the IOP was significantly reduced in group B and unchanged in group A (compared to preoperatively). Seventy-two percent of the eyes in group A and 79% of the eyes in group B achieved a visual acuity of 5/10 or better, respectively.

Aged↗

Pattern of characteristics in cataract patients.

Cataract extraction was performed in 1261 eyes. The relevant information was complete in 826 cases and thus only these were included in this study. Eleven variables describing clinical history, preoperative findings, operative problems and one variable representing visual acuity 4 months postoperatively were entered into a factor analysis model. Three factors were extracted by factor analysis, and these factors may be considered to be the underlying causes embracing the individual variables. Factor 1: the maculopathy factor; explained 23.3% of the total variance. Sixteen percent of the variance was attributable to Factor 2: the miosis factor. Lastly, Factor 3: operative problems; was responsible for 13.4% of the variance. The maculopathy factor was significantly associated with postoperative visual acuity (p < 0.001). Slight significant association was also found between the factor for operative problems and visual outcome, whereas no association was seen between the miosis factor and the final vision.

Adult↗

Cataract surgery with implantation of IOL in patients with uveitis.

Traditionally, IOL implantation in eyes with uveitis has not been recommended. In the present study 31 eyes with uveitis which underwent extracapsular cataract extraction or phacoemulsification with IOL implantation, are compared to a reference group consisting of 930 eyes. There was increased postoperative inflammation in 29% in the uveitis group, compared to 5.9% in the reference group. The rate of per- and postoperative complications was slightly elevated in the group with uveitis. Corrected visual acuity of 5/8.5 or better was achieved in 58.1%. The major obstacle to good visual acuity postoperatively, was macular pathology.

Cataract↗

The influence of age on characteristics of cataract patients.

The influence of age on 12 pre-, 1 intra-, and 2 postoperative patients' characteristics was investigated in 1261 consecutively performed extracapsular cataract extractions. The following characteristics were shown to be significantly associated with increasing age; cardiovascular disease (p < 0.0005), female gender (p < 0.0005), nuclear sclerosis (p < 0.0005), maculopathy (p < 0.0005), corneal guttate (p = 0.008) and reducing visual acuity in the fellow eye (p < 0.0005). Further, inadequate mydriasis at start of surgery was significantly associated with increasing age even after adjusting for glaucoma and pseudoexfoliation (p = 0.0007). After adjusting for pseudoexfoliation, a statistically significant relationship still existed between age and glaucoma (p = 0.0235). Even after controlling for relevant variables, i.e. maculopathy, a highly significant association was found between reducing visual acuity 4 months postoperatively and increasing age (p < 0.00005). Diabetes mellitus, the degree of cataract maturity, preoperative visual acuity of the operating eye, vitreous loss and postoperative inflammatory response were not significantly associated with increasing age.

Adult↗