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Biomedical subjects

M Norn

Publications and source records attributed to M Norn.

At least 19 recordsLinked to original sources
PubMed1994

Quantitative tear ferning. Clinical investigations.

The tears of 225 subjects were examined for several disorders of the eye by means of a newly developed method, the quantitative tear ferning test. Of the 225 subjects, 89 were normal controls, 24 were examined before and after cataract extraction, and 112 had some disease of the external part of the eye. Using the quantitative tear ferning test, it was shown that compared to normals, the ferning area was significantly decreased in cases of keratoconjunctivitis sicca, in primary and in secondary Sjögren's syndrome. This was also the case in infectious conjunctivitis and after cataract extraction, possibly due to exudation from the conjunctival vessels. In simple conjunctivitis, however, the ferning area was normal. The ferning method has a sensitivity and a specificity of the same order as the commonly used tests for Sjögren's syndrome (Schirmer I, BUT, rose bengale, lactoferrin).

Adult↗
PubMed1992

Pollution keratoconjunctivitis. A review.

In 'sick building syndrome' and other questionable environmental conditions, it is important to consider eye troubles. This review deals with several objective methods relevant for pollution keratoconjunctivitis. A hypothesis is put forward: A reduced lipid layer of the tear film causes reduced break-up time, increased vital staining and increased number of cells in the conjunctival fluid.

Air Pollution, Indoor↗
PubMed1992

Sampling methods for tear stix tests.

Four different methods for transferring conjunctival fluid to stix test pads were studied. One hundred and twenty eyes from 120 cataract-extracted patients (35 in the operated eye 0-5 days post-operatively and 85 in the contralateral eye) were included in the study. Transfer of fluid by a glass rod from the lateral part of the inferior fornix was demonstrated to be the most suitable method, showing the highest sensitivity to leucocyte-esterase (83%, N = 120, p < 0.05) and with a specificity equal to that of the other methods tested (cotton, spongostan, Schirmer paper strip). The glass rod method is suitable for detecting blood, nitrite, albumin, pH, and glucose, and is a both quick and unintrusive procedure. All four transferring methods may, however, cause an increased desquamation of epithelial cells and an increased amount of mucus.

Adult↗
PubMed1991

Quantitative tear meniscus cytology versus quantitative conjunctival fluid cytology.

A technique for quantitative cytology of tear fluid collected by a micropipette from the tear meniscus is presented. This technique has been compared with that using the standardized Norn-pipette collecting fluid from the lateral part of the inferior fornix. The two methods show the same magnitude of sensitivity and specificity, the same coefficient of variation, as regards neutrophilic leucocytes and erythrocytes (200 samples). The normal tear meniscus contains less than 40 leucocytes or erythrocytes per microliter. The tear cell concentration is about 200 times lower in the meniscus than in the fornix inferior in normal eyes. This observation supports the compartment-theory of a rapid flow in the tear meniscus and a slow flow with insignificant admixture in the conjunctival fluid in the fornices. The tear meniscus cytology is of use in association with testing of other parameters in the tears, for instance. The conjunctival fluid cytology is quicker and more convenient for the patient. In addition, it is necessary in connection with observation for pathological epithelial desquamation, because the tear meniscus cytology brings about an artificial increase of the epithelial cell concentration.

Conjunctiva↗
PubMed1991

Occult haemolacria in females.

A series of 125 healthy subjects were examined by the stix method (chemical response) for occult occurrence of blood in tears. Blood was found in 18% of fertile women, definitely most often in the menstrual phase (in 39% of 51 samples within the first week, reckoned from the first day of menstruation). The incidence was independent of use of the contraceptive pill. On the other hand, occult haemolacria was observed in no more than 7% (= 30) of pregnant women and in none at the menopause (N = 7). Among males the phenomenon was noticed in 8% (N = 24). Occult haemolacria in fertile women thus seems to be induced by hormones, whereas haemolacria most often is provoked by local factors (bacterial conjunctivitis, environmental damage, injuries).

Female↗
PubMed1991

Long-term changes in the outer part of the eye in welders. Prevalence of spheroid degeneration, pinguecula, pterygium, and corneal cicatrices.

Biomicroscopical examination of possible cumulative changes in the outer part of the eye in 217 male welders with variable welding exposure time showed conjunctival spheroid degeneration in 24% of the welders. The prevalence of changes was significantly increased in welders with the higher exposure time in an age-matched reduced material (98 x 2 eyes; respectively, over and under 40 h.y (number of daily hours of welding multiplied by number of years of welding), welders with stays abroad over one year being withdrawn. The prevalence was also increased in the latter group (41%, N = 40, against 21%, N = 177). Pinguecula was present in 57% of the welders, with a tendency towards larger area with increasing welding exposure. The frequency was increased as compared with that in a control material examined on a previous occasion (41%). Pterygium proper was found in only one subject, pseudopterygium in 5%. Corneal cicatrices were present in about one half of the subjects. The prevalence increased with increasing welding exposure (24% in subjects with short, 42% in those with long exposure; 98 x 2 eyes). Acute welding light keratopathy was experienced by 73%. The mean number of attacks in the 217 welders was 6.4. The frequency was highest in subjects with long welding exposure. The risk of chronic impairment of sight owing to cumulative welding light injuries is very little in the present material, since only 2% had spheroid degeneration on the cornea (only discrete, peripherally located); there was no preponderance of pterygium. On the other hand, the many foreign bodies on the cornea (cicatrices) constitute a risk that apparently does not decrease with increasing welding experience nor repeated attacks of welding light keratopathy.

Adolescent↗
PubMed1990

[A tear strip test in the control of contact lens wearers].

A series of 86 contact lens wearers has been examined by tear-stix tests (35 wearing hard lenses and 51 soft). Of these, 52 showed no infection (group A), while 34 had signs and/or symptoms of infection (group B). Leucocyte-esterase positivity was seen in 8% of group A and 62% of group B. Stix-positive were 13% of group A and 85% of group B (positive leucocyte-esterase and/or positive nitrite and/or positive hemoglobin). The examinations are quick and easy to carry out, with a reasonable sensitivity and specificity.

Clinical Enzyme Tests↗
PubMed1990

Hudson-Stähli's iron line in the cornea. Occurrence in 1968 and in 1988.

Examination of 700 persons in 1968 showed presence of Hudson-Stähli's iron line in 29%. A similar examination by the same author 20 years later revealed a significantly lower occurrence (18%) and fewer cases of binocular occurrence (70% against 43%). The line is most often horizontal. If oblique, it generally passes from the upper nasal to the lower temporal region.

Adolescent↗
PubMed1989

Tear stix tests for leucocyte-esterase, nitrite, haemoglobin, and albumin in normals and in a clinical series.

Tears are absorbed by a tuft of cotton and subjected to stix test for leucocyte-esterase (L), nitrite (N), haemoglobin (H), and albumin (A). Testing of 84 cases of infectious conjunctivitis and 282 normals revealed nosographic sensitivity to L in 89% and a specificity of 98%. By including N (only 26% positive with infectious conjunctivitis) and H the sensitivity rose to 98% while the specificity fell to 95%. A was generally raised in cases of infectious conjunctivitis. An additional number of 607 stix tests were carried out on a clinical series. The reaction was controlled before, during, and after cataract extraction. Conjunctivitis patients were observed for possible infection, the result of antibiotic treatment was studied, and contact lens wearers were controlled for infection. Predominantly stix-positive reaction was noticed in keratitis, allergic conjunctivitis, and ocular prosthesis socket. Predominantly negative reaction was seen in chronic simple conjunctivitis, sicca, scleritis, and iritis, the latter despite pronounced ciliary hyperaemia. Contralateral reflexly induced L and H were rendered probable. H-positive reaction predominated immediately after removal of suture. The tear stix test is easy to carry out, reasonably precise, and valuable in the clinical work.

Adolescent↗
PubMed1989

Hudson-Stähli's iron-line of cornea in Eskimos.

The Incidence of Hudson-Stähli's iron-line of the cornea (HS) has been studied in 1988 in a series of 265 Eskimos in the Angmagssalik district, East Greenland, and compared with that among 287 Caucasians in Copenhagen, Denmark. The author employed the same method of investigation for both series. HS is absent in young Eskimos less than 19 years), but present in 8 to 20 per cent in the remaining age groups. Eskimos and Caucasians are alike with regard to incidence, binocularity, grade, colour, and site. This goes to show that HS is of endogenous origin, bearing no relation to the frequent occurrence of haemolacria, pterygium, and astigmatism among Eskimos.

Adult↗
PubMed1988

Quantitative tear ferning. Methodologic and experimental investigations.

The reproducibility of different tear-ferning methods has been investigated by double tests on 122 subjects. Rough grading according to Rolando gives identical recovery in only 42 to 50%. Quantitative test (mm2 ferning per 1 microliter) of conjunctival fluid drawn with a glass rod according to Rolando gave a coefficient of variation of 99 to 128%. Aspiration with a quantitative pipette acc. to Norn 79%, and 55% for a standardized dilution (2.5 microliters of water) in the same pipette. The coefficient of variation was lower between tear samples aspirated through a thin capillary tube (1 mm = 0.5 microliter) from the lateral part of the tear meniscus (35%), and with a standardized tear volume (2.5 microliters) only 6.4%. Ferning is obstructed by ointment, fat emulsion dropped on the conjunctiva and mucous thread, but not by a glass slide rubber with stearin. A quantitative test with a capillary tube (2.5 microliters of aspirated lacrimal fluid) showed reduced ferning 30 sec after instillation of methylcellulose (2.5%) and arachis oil, and after expression of meibomian gland secretion. No significant alteration was observed after instillation of water or stimulation of the tear secretion by nasal inhalation of NH4OH.

Crystallization↗
PubMed1988

Double vital staining of corneal epithelium after corneal transplantation with a rose bengal-fluorescein mixture.

Longitudinal double vital staining with 1% rose bengal (RB) and 1% fluorescein (Flu) has been carried out on 33 eyes subjected to penetrating corneal transplantation. At the conclusion of the operation pronounced desiccation of both donor's and recipient's epithelium was seen in a scant 50%, but abrasion in only 8%. the desiccation subsided during the first post-operative day, but the donor's epithelium was rejected in the majority (91%). Healing started on the third day, manifesting itself by Flu-punctate whorl-shaped epithelium invading or gliding across the wound. By the fifth day nearly complete healing had occurred. In 9% no renewal of epithelium was noticed. Subsequent control examinations revealed loose sutures (RB-stained mucous adhesions), evanescent cicatricial defects, and open suture canals (Flu). Graft rejection occurred in 8 cases. In 5 of these, well-defined massive peripheral staining of donor epithelium was seen (RB most widespread and sharply outlined), and in the remaining 3, uncharacteristic, diffuse, punctate staining.

Cornea↗
PubMed1987

Expressibility of meibomian secretion. Relation to age, lipid precorneal film, scales, foam, hair and pigmentation.

The lower lids of 274 normal subjects have been examined in the slit-lamp for expressibility of secretion from the Meibomian glands. Secretion could be expressed from on an average 10 glands (median 11), dependent on age, decreasing with increasing age (from 14.5 glands at about the age of 20 to 7 glands above the age of 80). The expressibility was seen to be positively correlated to the thickness of the lipid layer of the precorneal film, estimated by the semiquantitative interference method. It was positively correlated to pigmentation and to ordinary greasy scales on the lid margin. The expressibility negatively correlated to retraction of the Meibomian orifices. The expressibility was found not to be correlated to elevated orifices, foam formation in the external part of the eye, cysts in the tarsus, nor with casts round the eyelashes. It is important to distinguish between cylindric casts (Demodex-induced) and ordinary greasy scales on eye lashes and lid margin.

Adult↗
PubMed1987

Foam in the external part of the eye.

Foam in the external part of the eye has been measured at the slit-lamp on 274 normal subjects. Foam occurred in 78%, most frequently in the outer canthus, on the skin round this, and in the lateral half of the lid margin. The age group of 30-50 years predominated. The foam-covered areas averaged 1.1 mm2, the largest amount always being found laterally (0.93 mm2). The lateral amount of foam was maximal in the age group of 30-50 years, while the medial maximum was seen in the age group of 60-70 years. The incidence of foam was not correlated to the lipid layer on the precorneal film, expressibility of Meibomian secretion, scales on the lid margin, or greasy hair. A hypothesis has been advanced for the mainly lateral position of the foam: blinking whips up the foam, which possibly has sebum admixed.

Adult↗