Glass, oxide, chemicals

Eye irritation

Administrative data

Endpoint:

eye irritation

Remarks:

other: Cross-sectional study of an exposed group with a matched nonexposed reference group

Type of information:

other: Human cross-sectional study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well documented publication which meets basic scientific principles.

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Data source

Reference

Reference Type:

publication

Title:

Ophtalmologic effects of man-made mineral fibres.

Author:

Stokholm J, Norn M, Schneider T

Year:

1982

Bibliographic source:

Scand J Work Environ Health; 8:185-190

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

A cross-sectional study of an exposed group with a matched nonexposed reference group. Matching criteria were age, sex and smoking habits.

The investigation program comprised an eye history, based upon a questionnaire and an interview, sampling of conjunctival fluid for quantitative cytology, a general medical examination of the external eye, slit lamp examination, measurement of ruptures in the precorneal film, break-up time, and vital staining of cornea and conjunctiva to reveal any microepithelial defects and dead or degenerated cells.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

MMVF note Q fibres

IUPAC Name:

MMVF note Q fibres

Details on test material:

- Name of test material (as cited in study report): Man-made mineral fibres (Rockwool®)

Test animals / tissue source

Species:

other: human (cross-sectional study)

Test system

Controls:

other: human (cross-sectional study)

Amount / concentration applied:

Occupational exposure.

Duration of treatment / exposure:

At least six months.

Number of animals or in vitro replicates:

15 workers

Details on study design:

The examination of the external eye was carried out in accordance with ophthalmologic practice. For the counting and classifying of cells in the conjunctival fluid, a quantitative method was used. In the exposed group, the coherent mucus in the inferior conjunctival fornix, the mucous thread, was removed from the right eye on the second examination after staining with 0.25% alcian blue (Microme no 24, Edward Gurr). The mucous thread was then examined for accumulated for accumulated test substance.
Break-up time was measured twice with a stop-watch after a 10 -µl drop of 0.125 % fluorescein (resorcinol phthalein) in isotonic sodium chloride had been instilled in the left eye. This procedure was followed by vital staining of the left eye with a 10 -µl drop of a fluorescein-rose bengal mixture. After 1 min of the installation all the fluorescein-stained microepithelial defects were counted in each of the following areas: lateral bulbar conjunctiva, cornea, medial bulbar conjunctiva, and inferior bulbar conjunctiva. Finally, rose bengal-stained degenerated or dead cells were also counted. In each area, the number of defects was subdivided into four groups: 1, 1-30, 31-200, 101-1000, >1000.

The exposed group included 15 workers (13 men and 2 women) who had been occupied with the production (control of production line), cutting, and packing of mineral wool for at least six months. Users of contact lenses were excluded. One woman in the exposed group was sick and absent from work on the second day of investigation. The mean age of each group was 38. The average tobacco consumption was 16 g/d.
The reference group was selected from the clerical staff of the plant and from employees of the National Institute of Occupational Health, Denmark. No member of the reference group had been exposed to dust, fibres, or solvents at work or to any large amount of fibres or dust in their spare time during the week before the investigation started.

Results and discussion

In vivo

Irritant / corrosive response data:

Only mechanical and reversible effects on the eyes are observed.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

Based on the data presented, it is evaluated that the E-glass microfibre is not an eye irritant and shall not be classified as irritating to the eye. This evaluation was also based on the Council Directive 67/548/EEC as the data presented is a human case study (adaptation from the Annex XI, 1.1.2).

Executive summary:

The case study on the effects of the occupational exposure in mineral wool workers was investigated along with a matched non-exposed control group in a cross-sectional study. After 4 working days the workers showed a significantly higher frequency of eye symptoms, microepithelial defects on medial bulbar conjunctiva and neutrophil cell count in conjunctival fluid. The effects were reversible. The mechanism was explained as the same foreign body reaction as is seen for skin irritation. The foreign body reaction can be compared to the mechanical irritant effect from a sand particle. The fibres will align along the surface.

It is evaluated based on the data presented that the E-glass microfibre shall not be classified as irritant to the eye according to the results.