Biomedical subjects
Publications and source records attributed to T Autzen.
Central corneal thickness was measured in 13 premature babies with a gestational age below 33 weeks. No difference was found between the thickness in the first and third post-natal week. At the age of 3 months the thickness had decreased significantly to the same level previously reported in full-term newborns. There was no correlation between gestational age, birth length and weight and central corneal thickness.
The technique of retinal nerve fibre photography has been developed and tested in specialized centres and glaucoma clinics. The usefulness of a modified technique in clinical practice is the subject of this prospective study. Retinal nerve fibre photos from 41 patients with open-angle glaucoma and 40 normal patients were examined in a blind study, a total of 161 eyes. Photos from 5 eyes were of insufficient quality to allow evaluation. Nerve fibre loss was found in 36% of the normal eyes, 42% of glaucomatous eyes without visual field defects, and 87% of eyes with glaucomatous visual field defects. Sensitivity was 86% and specificity was 62% totally. In the younger patients aged less than 65 years both values were 82%. Photographic nerve fibre loss was found in 69% of normal eyes from patients aged more than 65 years, leading to a low specificity of 31% in this age group. Age related nerve fibre loss and clinically insignificant cataracts were the most obvious causes of non-glaucomatous nerve fibre loss.
Correlation of psychophysical tests and structural changes is essential in the management of glaucoma. We compared the mean sensitivity and the short-term fluctuation in eyes with and without defects in the retinal nerve fibre layer in 41 glaucoma patients and 40 controls. In the glaucoma group 87.2% of eyes with visual field defects and 42.3% without visual field defects showed nerve fibre loss. In the control group 36.3% showed nerve fibre loss. In manifest glaucoma the mean sensitivity was 10.9 +/- 7.2 dB in eyes with nerve fibre loss and 19.2 +/- 3.9 dB in eyes without nerve fibre loss. This difference was statistically significant. The corresponding difference in glaucoma suspects and controls was not statistically significant. There was no difference between the short-term fluctuation in the three groups regardless of nerve fibre loss.
Knowledge of the effect of perimetric experience is essential in evaluation of visual fields. In the present study we report on the learning effect on short-term fluctuation (SF), and mean sensitivity (MS) correlating this effect with age in the older age groups. A sample of 33 volunteers with no history of ocular disease was subjected to two automated static perimetry tests. Program 32 of the Octopus 2000 was used for evaluation of the learning effect on SF and MS of the whole field, single quadrants and three eccentric zones. The learning effect on MS of the whole field and single zones of the first and the second session was statistically significant except in the upper temporal zone. Further, the learning effect showed a positive correlation with age on MS of the whole field, the lower quadrants and the eccentric zones from 0 to 20 degrees. The SF showed a significant learning effect, but no correlation with age could be demonstrated. However, SF increased significantly with age.
The central corneal thickness (CCT) was measured in 30 full-term newborns in the first week post partum using ultrasonic pachometry. The mean CCT in the right eyes was 0.581 +/- 0.047 mm. In 19 babies the CCT was measured twice. The mean CCT in the second reading was 0.584 +/- 0.042 mm. This difference was not statistically significant. There was no correlation between gestational age, birth weight and length, and CCT. The small difference between girls and boys was not statistically significant. The values in the left eyes were similar to the data for the right eyes. These results confirm the results in the only previous study on CCT in newborns, that is, that CCT is significantly larger than the CCT in adults.
Two patients with pigmented paravenous chorioretinal atrophy are presented. Both patients had chorioretinal atrophy with pigment clusters located in the paravenous areas, and one of the patients had macular affection. This patient had exotropia and juvenile cataract, the other patient had senile cataract. Electroretinography showed decreased, but not totally extinguished potentials. Automatic and manual perimetry revealed relative and absolute scotomas corresponding to the atrophic paravenous areas. To our knowledge this is only the sixth report of pigmented paravenous chorioretinal atrophy with macular affection.
Five patients with acute posterior multifocal placoid pigment epitheliopathy (APMPPE) have been subject to a follow-up study. All the patients had bilateral lesions. The follow-up period ranged from 1 month to 8 years (mean 4 years). All had resumed their previous work, although two patients had severe visual loss in one eye (6/36). No recurrences were observed. Automatic perimetry of the central visual field revealed moderate central scotomata between 5 and 10 db, corresponding to derangement of the pigment epithelium. This may indicate that the pigment derangement may be caused by alterations in the pigment granules in the pigment epithelial cells, and that the pigment epithelial cells have recovered. There were absolute scotomata in two eyes corresponding to chorioretinal atrophy.
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Timolol of 0.5% was applied in 6 eyes prior to cataract extraction, while 7 eyes were not treated. Aqueous humor was drawn after retrobulbar analgesia with 2% lidocaine and analyzed for epinephrine and norepinephrine using a radioenzymatic assay. Epinephrine levels averaged 15.8 +/- 16.2 and 19.3 +/- 27.5 pg/ml in the timolol treated group and controls respectively. The corresponding values for norepinephrine were 1.59 +/- 0.55 and 1.87 +/- 0.90 ng/ml. These differences were not statistically significant. Norepinephrine levels in this study were somewhat higher than in previous reports of catecholamine levels in human aqueous humor and considerably higher than plasma levels of norepinephrine. There was no significant correlation between aqueous humor norepinephrine levels and age in the two groups combined. The mean norepinephrine levels for men and women in the two groups combined were 1.73 +/- 0.89 and 1.76 +/- 0.56 ng/ml. The difference was not statistically significant. Timolol resulted in a decrease in the intraocular pressure.
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