PurposeTo evaluate the prevalence of pterygia and associated factors in a rural population in a mostly undeveloped agrarian region. MethodsThe Central India Eye and Medical Study is a population-based study performed in a rural region of Central India. The study comprised 4711 subjects (aged 30+ years). A detailed ophthalmic and medical examination was performed. A pterygium was diagnosed during the slit lamp examination and confirmed on corneal photographs. It was defined as a fleshy fibrovascular growth, crossing the limbus and typically seen on the nasal, and sometimes temporal, conjunctiva. ResultsA pterygium was detected in 798 eyes (prevalence rate: 8.47±0.29%) of 608 (12.91±0.49%) subjects. Bilateral pterygia were present in 190 subjects (4.0% of study population). Pterygia prevalence increased from 6.7±0.8% in the age group 30-39 years, to 13.5±1.2% in the age group 50-59 years, to 25.3±2.1% in the age group 70-79 years. Prevalence of pterygia was associated with older age (P<0.001; regression coefficient B: 0.02; odds ratio (OR): 1.02; 95%CI: 1.01, 1.03), male gender (P<0.001;B:-0.73;OR: .48;95%CI:0.39,0.61), lower level of education (P<0.001;B:-0.30;OR:0.74;95%CI:0.69,0.80), lower body height (P=0.001;B:-0.02;OR:0.98;95%CI:0.97,0.99), and higher cylindrical refractive error (P<0.001;B:0.23;OR:1.26;95%CI:1.18,1.34). If the education level was dropped, the number of hours spent with vigorous activity outdoors (P=0.001;B:0.001;OR:1.001;95%CI:1.000,1.0001) was significantly associated with the prevalence of pterygia, in addition to older age (P<0.001;B:0.03;OR:1.03;95%CI:1.03,1.04), male gender (P<0.001;B:-0.49;OR:0.62;95%CI:0.49,0.77), lower body height (P=0.005;B:-0.02;OR:0.98;95%CI:0.97,0.99), and higher cylindrical refractive error (P<0.001;B:0.23;OR:1.25;95%CI:1.18,1.34). ConclusionsPterygium prevalence in rural Central India is about 13% among adult Indians aged 30+ years. Older age, male gender, lower educational level, lower body height and more time spent outdoors with vigorous work were associated factors. Since the living conditions in the study location were mostly untouched by modern developments, the results may show the prevalence and associations of pterygia without major medical or technologic influences.

In this adult rural Central Indian population with low mean BMI, the prevalence of corneal arcus was 10.7% ± 1.0%. The only systemic parameter associated with corneal arcus was increasing age (P < 0.001). Corneal arcus was not associated with dyslipidemia, diabetes mellitus, arterial hypertension, alcohol consumption, or smoking. In this population with low BMI, corneal arcus was not a clinical biomarker for major metabolic disorders. The intereye associations between corneal arcus and low intraocular pressure, thin central cornea, and hyperopia may be of importance in the ophthalmic examination.