Related Experiment Video
Updated: Feb 3, 2026

Assessing the Particulate Matter Removal Abilities of Tree Leaves
Published on: October 7, 2018
Ocular Exposure to Particulate Matter and Development of Pterygium: A Case-Control Study
Carlos Alberto Ramirez1, Manuel Pérez-Martinot2, Delia Gil-Huayanay3
1Escuela de Posgrado, Universidad ESAN, Lima, Perú.
Background:
Formation of pterygium has been mainly attributed to exposure to the ultraviolet (UV) radiation. Other factors such as dry weather, wind exposure and microtrauma with dust particles, have been linked to development of pterygium.
Objective:
To determine the association between ocular exposure to particulate matter and development of pterygium.
Methods:
This case-control study was conducted in a company dedicated to the production and marketing of toilets. We included a total of 90 cases identified in November 2013 and 184 controls. The diagnosis of pterygium was based on clinical examination. Variables studied included age and job tenure of the participants. Logistic regression analysis was used to assess the effect of exposure on developing pterygium.
Results:
All study participants were male. The mean age of the cases and controls was 39.9 (SD 9.5) and 37.8 (SD 7.3) years, respectively. 115 (42%) of the participants had a job tenure of 5-8 years. The percentages of cases and controls exposed to particulate matter were 31.1% (n=28) and 30.4% (n=56), respectively (OR 1.08, 95% CI 0.61 to 1.91).
Conclusion:
We could not observe any association between ocular exposure to particulate matter and development of pterygium.
Related Concept Videos
Classifying Matter by State
Classifying Matter by Composition
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures.
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.
A mixture is composed of two or...
Physical and Chemical Properties of Matter
What is Matter?
The Atomic Theory of Matter
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...

