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Biomedical subjects

M Norn

Publications and source records attributed to M Norn.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1987

Relation between blink frequency and break-up time?

A possible correlation between break-up time (BUT) and blink frequency was investigated in 32 healthy persons (17 females and 15 males) and in 29 patients suffering from primary Sjögren's syndrome (27 females and 2 males). A significant negative correlation, was found between BUT and blink frequency. In persons with high BUT, the blink frequency is low, probably just sufficient to prevent spontaneous tear breaks. In persons with low BUT, i.e. the Sjögren patients, the blink frequency is high, and tear fluid breaks are mostly prevented.

Adult↗
PubMed1987

Ferning in conjunctival-cytologic preparations. Crystallisation in stained semiquantitative pipette samples of conjunctival fluid.

Two quantitative pipette samples and 3 smears from each of 305 eyes were re-evaluated. Two types of ferning (F) were detected i.e. rectangular (FR) and acute-angled (FA) ramifications, respectively. One FR corresponds in area to 0.11 FA. Ferning was present in 29% of pipette samples, averaging 0.41 mm2 in the form of FR in the total series. Ferning was most frequent in samples with fairly large amounts of mucus, more frequent in neutrophilia than in lymphocytosis, and the rarest in normal cytology. F was seen in several cases of acute infections conjunctivitis (55%), neonatal and follicular conjunctivitis, and keratitis, whereas it was rare in normal eyes (7%). This distribution is presumably due to the amount of mucus in the samples preserving the F-pattern during the preparation procedure. F was rarely seen in smears (0.7%).

Conjunctiva↗
PubMed1985

Pigment spots related to scleral emissaries in Eskimos, Mongols, and Caucasians.

Examinations of a series of 1241 subjects showed episcleral pigment spots bearing relation to scleral canal emissaries to be most frequent among Eskimos (prevalence 85%), somewhat less frequent among Mongols (68%), and the rarest among white Northern Europeans (16%). The prevalence is the highest among women and rises very little with increasing age. The pigmentation is most often bilateral in Eskimos (66%), more rarely so in Caucasians (18%). It is most often localized superiorly (54%). Then follows in decreasing order to frequency:inferiorly (26%), nasally (13%), and - significantly more rarely - temporally (7%). The pigmentation is most often related to an artery (90%), most often one running a radial course (39%) or in the incyclo-direction (32%). Its average length in caucasians is 1.1 mm. Pigmentations are significantly related to the colour of the iris (visible in 8% of blue irides, against in 40% of brown).

Adolescent↗
PubMed1985

Meibomian orifices and Marx's line. Studied by triple vital staining.

The ciliary margins of the lower lids have been vital stained by the lipid-specific Sudan III powder, fluorescein 0.1% and the bottom of the lacrimal river (Marx's line) by lissamine green 1% in 100 cases. The Meibomian orifices are situated in a straight row just in front of the Marx's line in the lipid phase. With increasing age (greater than 50 years) the orifices are more often displaced and also discharge their lipid in the depth of the aqueous phase. The number averaged 21.5 in the lipid phase and 1.7 in the aqueous phase. Active orifices staining with lipid were found in 45% of all orifices in normals, independent of age, and were increased in conjunctivitis in the lipid phase. Lissamine green-stained orifices were independent of age, phase and diagnosis. The anterior edge of Marx's line may run an irregular course in elderly normals (greater than 50 years), significantly more often in conjunctivitis and blepharitis.

Adolescent↗
PubMed1985

Topography of scleral emissaries and sclera-perforating blood vessels.

One hundred persons have been subjected to slit-lamp examination for scleral emissaries. The number registered per subject averaged 12.2. Such were most frequent superiorly at 12 o'clock and inferiorly at 6 o'clock, rarer nasally and the rarest temporally. The courses of the perforating blood vessels were equally often radial (30%), incyclo-directed (28%), and excylodirected (29%), whereas rarely parallel with the limbus corneae (10%), and even more rarely irregularly winding (3%). Episcleral pigmentation in relation to emissaries was most frequently observed superiorly and where the vessels ran radial and limbus-parallel courses, whereas rarely nasally and temporally and at excyclo-directed and winding courses.

Adult↗