Tear film layers and meibomian gland assessment in patients with type 1 diabetes mellitus using a noninvasive ocular surface analyzer: a cross-sectional case-control study.

PURPOSE: To assess the tear film layers and Meibomian glands by a noninvasive ocular surface analyzer in patients with and without type 1 diabetes mellitus (T1DM). METHODS: Eighty-eight participants were enrolled in this study: 44 patients with T1DM without diabetic retinopathy, and 44 patients as a control group, between 18 and 49 years old. Limbal and bulbar redness classification, lipid layer thickness (LLT), tear meniscus height (TMH), first and mean noninvasive tear break-up time (FNIBUT and MNIBUT, respectively), and Meibomian glands loss (MGL) were assessment through the ICP Ocular Surface Analyzer (OSA). Schirmer's I test (SIT), the fluorescein tear break-up time test (TFBUT), OSDI and SPEED questionnaires, and percentage of glycosylated hemoglobin (HbA1c) were also tested. RESULTS: The T1DM group showed higher limbal and bulbar redness (p = 0.010) and lower LLT (p < 0.001), TMH (p < 0.001), FNIBUT (p < 0.001), MNIBUT (p < 0.001), SIT (p = 0.001), and TFBUT (p < 0.001) than the control group. A higher percentage of MGL was found in the T1DM group in the upper (p = 0.097) and lower (p < 0.001) eyelids. No significant differences were found in dry eye symptoms across the OSDI and SPEED questionnaires between the two groups. CONCLUSION: Patients with T1DM without signs of retinopathy showed involvement of the mucoaqueous and lipid layers of the tear film, as well as a higher percentage of MGL, using a noninvasive analyzer. Dry eye disease in people with T1DM cannot be ruled out by anamnesis and subjective symptom questionnaires alone; therefore, these patients should undergo regular anterior pole examinations.

Contrast Sensitivity Assessment in Early Diagnosis of Diabetic Retinopathy: A Systematic Review.

INTRODUCTION: The purpose of this systematic review was to study whether contrast sensitivity assessment in people with diabetes could be a reliable test in early detection of diabetic retinopathy. A systematic search based on population, intervention, comparison, and outcome strategy was performed. METHODS: PubMed, Scopus, and Web of Science were searched for English articles of human patients with type 1 and type 2 diabetes and contrast sensitivity measurements as domain studied. RESULTS: Twentyone comparative cross-sectional studies were included. All of them showed significant loss of contrast sensitivity in people with diabetes and diabetic retinopathy regarding control patients of the same age, regardless of the method used. However, those without diabetic retinopathy, involve a loss of contrast sensitivity, although not always significant. CONCLUSION: Changes in contrast sensitivity suggest that there is damage to the retina prior to the vascular ones and that they could be detected by this test.

Choroidal thickness assessment in keratoconus patients treated with cross-linking compared to healthy population.

PURPOSE: To analyze the choroidal thickness between patients with keratoconus undergoing cross-linking treatment and a healthy population, as well as to determine the factors that influence choroidal thickness. METHODS: This was an observational, analytical, case-control study that was conducted from February 2021 to June 2021. Choroidal thickness was measured at different locations, including the subfoveal, nasal (1000 µm), temporal (1000 µm), superior (1000 µm) and inferior (1000 µm) locations using a Spectral-domain optical coherence tomography with enhanced depth imaging, which allowed us to obtain horizontal and vertical B-scans centered on the fovea. RESULTS: This study included 21 patients with keratoconus (mean age, 21.86 ± 5.28 years) and 28 healthy patients (mean age, 24.21 ± 4.71 years). Choroidal thickness was significantly greater in patients with keratoconus than in healthy patients in each of the following measured locations: subfoveal (P < 0.001); nasal (1000 µm) (P < 0.001), temporal (1000 µm) (P < 0.001), superior (1000 µm) (P < 0.001) and inferior (1000 µm) (P < 0.001) locations. Variables such as age (ρ = - 0.09; P = 0.50) and refraction (ρ = 0.14; P = 0.34) were not found to be associated with choroidal thickness. In a stepwise multiple linear regression, the group was the single variable correlated with choroidal thickness (ß = 0.88; P < 0.001). CONCLUSION: Choroidal thickness is thicker in keratoconus patients treated with cross-linking than in the healthy population. This finding could be associated with inflammatory choroidal mechanisms in keratoconus patients, but more studies are needed. Age and refractive error do not seem to influence choroidal thickness.

Dry eye disease and tear film assessment through a novel non-invasive ocular surface analyzer: The OSA protocol.

We describe the role of OSA as a new instrument in the study of dry eye, and we recommend a protocol for conducting the tests as well as describe the advantages and disadvantages compared with other instruments. A comparison with other ocular surface devices (Tearscope Plus, Keratograph 5M, anterior-segment ocular coherence tomography, Easy Tear View-Plus, LipiView, IDRA, and LacryDiag) were presented due to manual or automatic procedure and objective or subjective measurements. The purpose of this study was to describe the OSA as new non-invasive dry eye disease diagnostic device. The OSA is a device that can provide accurate, non-invasive and easy-to-use parameters to specifically interpret distinct functions of the tear film. This OSA protocol proposed a lesser to higher non-invasive ocular surface dry eye disease tear film diagnostic methodology. A complete and exhaustive OSA and OSA Plus examination protocol was presented within the subjective questionnaire (Dry Eye Questionnaire 5, DEQ5), limbal and bulbar redness classification (within the Efron grade Scale, interferometry lipid layer thickness (LLT) (according to Guillon pattern), tear meniscus height (manually or automatic), first and mean non-invasive break up time (objective and automatic) and meibomian gland (MG) dysfunction grade and percentage (objective and automatic). The OSA and OSA Plus devices are novel and relevant dry eye disease diagnostic tools; however, the automatization and objectivity of the measurements can be increased in future software or device updates. The new non-invasive devices supposed represent a renewal in the dry eye disease diagnosis and introduce a tendency to replace the classic invasive techniques that supposed less reliability and reproducibility.