Alzheimer’s disease (AD) is an age-related progressive neurodegenerative brain disorder that represents the most common type of dementia. It poses a significant diagnostic challenge that requires timely recognition and treatment. Currently, there is no effective therapy for AD; however, certain medications may slow down its progression. The discovery of AD biomarkers, namely, magnetic resonance imaging, positron emission tomography and cerebrospinal fluid molecules (amyloid-β and tau) has advanced our understanding of this disease and has been crucial for identifying early neuropathologic changes prior to clinical changes and cognitive decline. The close interrelationship between the eye and the brain suggests that tears could be an interesting source of biomarkers for AD; however, studies in this area are limited. The identification of biomarkers in tears will enable the development of cost-effective, non-invasive methods of screening, diagnosis and disease monitoring. In order to use tears as a standard method for early and non-invasive diagnosis of AD, future studies need to be conducted on a larger scale.

Sexual dimorphism significantly impacts the lacrimal gland’s structure, function, and ageing processes, playing an important role in dry eye disease (DED) pathophysiology. This multifactorial disorder, characterised by tear film instability, inflammation, and visual impairment, disproportionately affects women, especially after menopause. It highlights the interplay between sex steroid hormones, lacrimal gland function, and environmental factors. Systemic and local androgens are vital for maintaining lacrimal gland health and tear production, while the role of oestrogens remains less clear. Evidence suggests dose and context-dependent effects on inflammation and glandular function. Histopathological and molecular studies reveal significant sex differences in the lacrimal gland, with women exhibiting more pronounced age-related degenerative changes, including fibrosis and acinar atrophy, contributing to their increased susceptibility to DED. Despite these findings, the underlying mechanisms connecting sex steroid hormones, receptor expression, and local tissue regulation to these disparities remain poorly understood, highlighting the need for further research. This review synthesises the current knowledge of sex-specific differences in the lacrimal gland, emphasising the importance of integrating systemic and local biomarkers, histological data, and molecular insights into personalised therapeutic strategies. By tailoring treatments to patients’ unique hormonal and molecular profiles, personalised medicine has the potential to transform DED management, addressing unmet clinical needs and improving outcomes.

Dry eye disease (DED) is a highly prevalent multifactorial disorder of the ocular surface that extends beyond local tear film pathology to involve systemic immune, neuroendocrine, and neurosensory mechanisms. Increasing evidence reveals a strong and bidirectional association between DED and psychiatric disorders, particularly depression, anxiety, post-traumatic stress disorder (PTSD), and sleep disturbances. This review synthesises the current knowledge on shared molecular, neuroimmune, and neuropathic pathways that underlie this comorbidity. Key mechanisms include hypothalamic–pituitary–adrenal (HPA) axis dysregulation, systemic and ocular inflammation, oxidative stress, mitochondrial dysfunction, and impaired neurotrophic signaling, especially reduced brain-derived neurotrophic factor (BDNF). Dysregulation of monoaminergic neurotransmitters such as serotonin and norepinephrine not only contributes to mood disturbances but also alters tear secretion and corneal pain perception. Corneal nerve changes and trigeminal–limbic sensitisation further reinforce the overlap between neuropathic ocular pain and affective dysregulation. Psychotropic medications, while essential for psychiatric care, may exacerbate ocular surface dysfunction through anticholinergic effects, altered neurotransmission, and tear film instability, highlighting the iatrogenic dimension of this interface. Conversely, tear-based biomarkers, including cytokines, serotonin, and BDNF, offer promising translational tools for patient stratification, diagnosis, and treatment monitoring across ocular and psychiatric domains. Recognising DED as part of a systemic, biopsychosocial continuum is critical for effective management. Multidisciplinary strategies that integrate ophthalmologic and psychiatric care, alongside novel therapies targeting shared molecular pathways, provide a framework for improving outcomes. Future research should prioritise longitudinal studies, biomarker validation, and personalised interventions to address this complex comorbidity.

Mitochondrial reactive oxygen species (mtROS) play a dual role in retinal physiology, acting as essential redox signalling mediators under homeostatic conditions but driving oxidative damage and neurodegeneration once regulatory thresholds are exceeded. Owing to the exceptionally high energetic demands of retinal neurons and supporting cells, even subtle perturbations in mitochondrial redox balance can precipitate progressive retinal dysfunction. Increasing evidence indicates that retinal neurodegenerative diseases, including glaucoma, diabetic retinopathy (DR), age-related macular degeneration (AMD), and inherited optic neuropathies, are characterised not by uniform oxidative stress, but by disease- and stage-specific mtROS signatures shaped by mitochondrial quality control capacity. This review synthesises current insights into the sources, regulation, and signalling functions of mtROS in the retina, with particular emphasis on threshold-dependent redox transitions, reverse electron transport, and the progressive failure of mitochondrial quality control mechanisms, including mitophagy, mitochondrial dynamics, and redox-responsive transcriptional networks. The limitations of non-selective antioxidant strategies are critically examined, highlighting why indiscriminate ROS suppression has yielded limited clinical benefit. In contrast, emerging therapeutic approaches aimed at recalibrating mitochondrial redox homeostasis, rather than abolishing physiological signalling, are discussed in the context of disease stage, metabolic state, and mitochondrial competence. By integrating redox biology with mitochondrial quality control and precision medicine concepts, this review proposes a unifying framework in which retinal neurodegeneration is governed by regulated mtROS signalling and the progressive exhaustion of mitochondrial resilience. This model defines critical therapeutic windows for mitochondria-targeted intervention and provides a framework for biomarker-guided patient stratification.

Obstructive sleep apnoea (OSA) is a prevalent condition characterised by intermittent upper airway obstruction during sleep, resulting in recurrent hypoxia and sleep fragmentation. Emerging evidence highlights the significant impact of OSA on neuro-ophthalmological health, linking it to conditions such as glaucoma, optic neuropathy, papilledema, and visual field defects. These associations emphasise the importance of understanding the mechanisms connecting OSA to neuro-ophthalmological disorders to enhance early diagnosis and management. This review explores the pathophysiological pathways, including hypoxia-induced vascular dysregulation, oxidative stress, inflammation, and intracranial pressure fluctuations, that contribute to ocular and neurological impairments in OSA patients. Advanced diagnostic tools, such as optical coherence tomography and polysomnography, offer promising avenues for detecting subclinical neuro-ophthalmological changes, enabling timely intervention. Management strategies, primarily centred on continuous positive airway pressure therapy, have shown efficacy in mitigating OSA-related neuro-ophthalmological complications. However, surgical and pharmacological interventions and lifestyle modifications remain vital components of a multidisciplinary approach to care. Despite advancements, significant research gaps persist, particularly in understanding the long-term impact of OSA treatment on neuro-ophthalmological outcomes and identifying specific biomarkers for early detection. Future research should prioritise longitudinal studies, interdisciplinary collaborations, and personalised medicine approaches to address these challenges. Recognising and treating neuro-ophthalmological disorders in OSA patients is imperative for improving quality of life and preventing irreversible visual and neurological damage.

Ocular melanomas, comprising uveal melanoma (UM) and conjunctival melanoma (CoM), represent the most common primary intraocular and ocular surface malignancies in adults. Although rare compared with cutaneous melanoma, they exhibit unique molecular landscapes that provide critical opportunities for biomarker-driven precision medicine. In UM, recurrent mutations in GNAQ and GNA11, together with alterations in BAP1, SF3B1, and EIF1AX, have emerged as key prognostic biomarkers that stratify metastatic risk and guide surveillance strategies. Conversely, in CoM, the mutational spectrum overlaps with cutaneous melanoma, with frequent alterations in BRAF, NRAS, NF1, and KIT, offering actionable targets for personalised treatment. Beyond genomics, epigenetic signatures, microRNAs, and protein-based markers provide further insights into tumour progression, microenvironmental remodelling, and immune evasion. In parallel, liquid biopsy has emerged as a minimally invasive approach for real-time disease monitoring. Analyses of circulating tumour DNA (ctDNA), circulating tumour cells (CTCs), and exosome-derived microRNAs demonstrate increasing potential for early detection of minimal residual disease, prognostic assessment, and evaluation of treatment response. However, the clinical integration of these biomarkers remains limited by tumour heterogeneity, technical variability, and the lack of unified translational frameworks. This review synthesises current knowledge of molecular and liquid biopsy biomarkers in ocular melanoma, highlighting their relevance for diagnosis, prognosis, and treatment personalisation. The integration of established tissue-based molecular markers with novel liquid biopsy technologies will enable a unique framework for biomarker-guided precision oncology and risk-adapted surveillance in uveal and conjunctival melanoma, offering insight into strategies for early detection, therapeutic monitoring, and personalised clinical management.