The primary role of meibomian glands (MGs) is to actively synthesize and secret lipids and proteins spread onto the tear film, and the glandular lipids promote tear stability, prevent evaporation, and reduce friction. Meibomian gland dysfunction (MGD) is the leading cause of dry eye disease and one of the most common ophthalmic problems worldwide. MGs are densely innervated and regulated by hormones and growth factors. However, since the polar and nonpolar lipids are produced through processes in MGs that are not completely understood, a relevant question has been raised: Would the altered systemic lipids metabolism affect the physiology and structure of MGs? This review introduces the recent update regarding the relationships between serum lipid and MGD in clinical and basic research while providing answers to this question. A causal relationship remains to be established; however, serum lipid level or dyslipidemia may be related to MGD directly or indirectly, or both. Further studies are warranted to establish the role of serum lipid level and meibocyte differentiation/maturation and lipid synthesis.

Purpose: To predict the effective lens position (ELP) using conditional process analysis according to preoperative axial length. Setting: Yeouido St. Mary hospital. Design: A retrospective case series. Methods: This study included 621 eyes from 621 patients who underwent conventional cataract surgery at Yeouido St. Mary Hospital. Preoperative axial length (AL), mean corneal power (K), and anterior chamber depth (ACD) were measured by partial coherence interferometry. AL was used as an independent variable for the prediction of ELP, and 621 eyes were classified into four groups according to AL. Using conditional process analysis, we developed 24 structural equation models, with ACD and K acting as mediator, moderator or not included as variables, and investigated the model that best predicted ELP. Results: When AL was 23.0 mm or shorter, the predictability for ELP was highest when ACD and K acted as moderating variables (R2 = 0.217). When AL was between 23.0 mm and 24.5 mm or longer than 26.0 mm, the predictability was highest when K acted as a mediating variable and ACD acted as a moderating variable (R2 = 0.217 and R2 = 0.401). On the other hand, when AL ranged from 24.5 mm to 26.0 mm, the model with ACD as a mediating variable and K as a moderating variable was the most accurate (R2 = 0.220). Conclusions: The optimal structural equation model for ELP prediction in each group varied according to AL. Conditional process analysis can be an alternative to conventional multiple linear regression analysis in ELP prediction.

Dry eye disease (DED) is a multifactorial ocular disorder marked by tear film instability, oxidative stress, and inflammation. Although melatonin is known to exert antioxidant and anti‐inflammatory effects, its precise role in regulating desiccation‐induced stress responses at the ocular surface has not been well defined. In particular, the involvement of the Nrf2 signalling pathway in melatonin‐mediated protection against corneal epithelial inflammation under tear film instability remains unexplored. In this study, we evaluated the therapeutic potential of melatonin in a human corneal epithelial cell (HCEC) model mimicking desiccation stress. Melatonin treatment significantly reduced reactive oxygen species (ROS) levels and upregulated antioxidant enzymes, including catalase (CAT) and heme oxygenase‐1 (HO‐1), via Nrf2 pathway activation. These effects were attenuated by Nrf2 knockdown using siRNA, confirming pathway specificity. Furthermore, melatonin markedly suppressed pro‐inflammatory cytokine production, suggesting a dual mechanism of action involving both redox regulation and immune modulation. Our findings provide novel insight into the Nrf2‐dependent effects of melatonin on ocular surface protection under desiccation conditions. These results suggest melatonin as a promising candidate for the treatment of DED through simultaneous modulation of oxidative and inflammatory pathways specific to tear film instability.

Background/Objectives: This study aimed to analyze the accuracy of the SRK/T, Haigis, Barrett Universal II (BUII), Kane, and EVO intraocular lens (IOL) formulas for normal and long axial length (AL) groups using an ARGOS (Alcon, Fort Worth, TX, USA), which uses the specific refractive indices. Methods: We performed a review of patients who underwent uneventful cataract surgery with the implantation of an Acrysof IQ SN60WF IOL (Alcon, Inc.) between January 2020 and December 2021. Biometry was obtained with the ARGOS; patients were separated into subgroups based on AL as follows: normal (22.0 ≤ AL < 26.0 mm) and long (AL ≥ 26.0 mm). Outcomes included the mean error (ME), the mean absolute error (MAE), the median absolute error (MedAE), and the proportion of eyes within ±0.25, ±0.50, ±0.75, and ±1.00 diopters (D) of the prediction error. Results: A total of 191 eyes of 191 patients were included: 162 eyes of 162 patients in the normal AL group and 29 eyes of 29 patients in the long AL group. The EVO formula was the most accurate for the normal AL group, which had the lowest MAE and MedAE. The MAE and MedAE of EVO were the lowest in the long AL group; EVO showed the highest percentage of eyes within ±0.25, ±0.75, and 1.00 D compared with other formulas. Conclusions: When using an ARGOS, the EVO formula had the lowest MAE and the highest proportion of eyes within ±1.00 D of the predicted target in both the normal and high myopia groups.