A case-control study of the ocular surface and tear film parameters in gestational diabetes mellitus.

Purpose: Gestational diabetes mellitus (GDM) is fairly common in India. There is an interplay of various factors like androgens, sex hormone-binding globulin (SHBG), estrogen, and progesterone on the tear film in pregnancy. Diabetes mellitus in itself affects the lacrimal function unit (LFU) and ocular surface. This study was therefore performed to assess the effect of the various factors on the tear film function and ocular surface in GDM using different diagnostic tests. Methods: Case-control study includes 49 subjects after calculating the sample size. Cases of newly diagnosed GDM in their second or third trimester of pregnancy without any ocular or systemic comorbidities. The following standard tests were performed, namely, ocular surface disease index (OSDI) scoring, Schirmer's test, tear film breakup time (TBUT), and ocular surface staining (SICCA). Results: The two study groups did not differ significantly in terms of age, gestational age, and presenting symptoms. None of the patients had diabetic retinopathy, and the ocular surface was unaffected in both groups. There was a significant difference in the Schirmer's II test (P = 0.01) between the groups, while Schirmer's I (P = 0.06) and TBUT (P = 0.07) were not significant. Conclusion: Our study suggests that GDM patients can potentially suffer from DES despite the lack of symptoms and may be the basis for conducting larger studies to justify routine screening of GDM for DES in order to improve the quality of life of pregnant women.

Can ultrasonic biometric indices with optimal cut-offs be a potential screening tool for primary angle closure disease? A case-control study.

BACKGROUND/OBJECTIVES: Despite a significant disease burden and potential to cause blindness, primary angle closure disease (PACD) does not have a population-based screening programme. Biometric indices using ultrasound A-scan is a potential tool for glaucoma case-detection. Given that genetic and environmental factors influence these parameters and paucity of data on their discrimination thresholds in Indian populace, we conducted a matched case-control study to determine the biometric indices and their discrimination thresholds associated with PACD. METHODS: We studied 172 eyes of 86 participants (43 cases; 43 controls). We compared the following biometric parameters of cases (PACD, occludable angle ≥180° ± raised intraocular pressure) with age and gender-matched controls (1:1): Anterior chamber depth (ACD), lens thickness (LT), axial length (AXL), lens position (LP), relative lens position (RLP), lens axial factor (LAF), simple crowding value (Cs), ACD/AXL). We performed conditional logistic regression (to identify factors associated with PACD) and Receiver operating characteristic (ROC) analysis (to determine discrimination thresholds). RESULTS: Reduced ACD (Adj OR 0.01; 95% CI: 0.0003-0.15, p < 0.001) and increased LT (Adj OR 10.3; 95% CI:2.42-43.93, p < 0.001) were associated with PACD. On ROC analysis, ACD, Cs, and ACD/AXL had optimum sensitivity/specificity at ≤3.015, ≥0.056 and ≤0.1303, respectively. ACD (88.4%) and Cs (94.2%) had highest sensitivity and specificity, respectively. CONCLUSION: Ultrasonic biometric parameters differed significantly between PACD and controls. ACD and Cs (at discrimination thresholds of ≤3.015 mm and ≥ 0.056, respectively) using ultrasound A-scan could be a potential tool for PACD case-detection that requires evaluation of its diagnostic yield and cost-effectiveness.