DED is defined as a multifactorial condition that affects the tears and the ocular surface, leading to discomfort, visual disturbances, tear film instability, and potential damage to the ocular surface. It is characterised by increased tear film osmolarity and subacute inflammation of the ocular surface.¹

The impact of DED on daily life

DED poses a considerable burden on individuals' daily lives. It impairs functional vision, particularly during activities such as reading, computer usage, and driving.¹

Reduced reading speed is a common consequence of DED and is correlated with the severity of the disease. Furthermore, DED can lead to a reduced quality of life (QoL), akin to the decrease reported in QoL for angina pectoris. Many patients also experience decreased work efficiency due to DED symptoms.¹

Classification of DED

DED can be classified into two main categories:²

• Dry eye with reduced tear production (aqueous-deficient), which affects ~10% of patients.
• Dry eye with increased evaporation of the tear film (hyper-evaporative), which affects >80% of patients.

Symptoms of DED

The symptoms of DED are often non-specific but can include redness, burning, stinging, foreign body sensation, pruritus (itchiness), and photophobia (sensitivity to light). In severe cases, conjunctival scarring or corneal complications may develop.²

Multifaceted risk factors

Several risk factors contribute to the development of DED, transcending the conventional notion of age as the primary risk factor.¹

• Age and lifestyle: While age is a significant risk factor, studies have shown unexpectedly high rates of DED among younger individuals, highlighting the influence of non-age-related factors. Lifestyle and behavioural elements such as contact lens use, excessive screen time, poor sleep quality, allergies, arthritis, smoking, certain medications, ocular surgery, and environmental conditions like low humidity and air-conditioning have been linked to DED in young adults and children.¹
• Gender: Women are at a higher risk of DED across various population studies, encompassing both Sjögren and non-Sjögren types. Gender-related differences in pain perception and tolerance may play a role in reporting ocular surface and DED symptoms. However, an African study showed very little difference in the prevalence of DED in women (44%) compared to men (42%).^1,3
• Ethnicity: Significant ethnic variations in DED prevalence exist, with Southeast Asians having a notably higher risk. The prevalence of DED in Africa is ~42%.^1,3
• Genetics and environment: The interplay between genetics and the environment contributes to DED. Heritability for dry eye symptoms ranges from 25% to 80% for different symptoms, with moderate heritability noted for clinician-diagnosed dry eye.¹
• Comorbidities: DED is frequently associated with various systemic conditions, including allergies, arthritis, thyroid disease, and renal failure. Neuropsychiatric diseases such as depression and anxiety have also been linked to more severe DED symptoms. Medication use, including proton pump inhibitors, anticholinergic drugs, and topical anti-glaucoma medications, is independently linked to DED symptoms.¹
• Societal factors: Nutritional status and eating behaviours significantly impact ocular surface health. Smoking, substance use (including alcohol, caffeine, and recreational drugs), traditional medicines, and recreational activities and sports can all affect the ocular surface.¹

The role of artificial tears in DED management

Patient education is pivotal in managing DED, given its chronic nature and the need for long-term treatment. The treatment approach varies based on disease severity and associated factors, such as meibomian gland dysfunction and ocular surface inflammation.⁴

Artificial tears stand as a cornerstone therapy for DED across all severity levels, offering several benefits, including enhancing tear film stability, reducing ocular surface stress, improving contrast sensitivity, and enhancing overall quality of life.⁴

Artificial tears come in various formulations, with the choice depending on disease severity. Products without benzalkonium chloride as a preservative are preferred for ocular surface disorders. For meibomian gland dysfunction, artificial tears containing lipids have shown promise.⁴

In severe cases, autologous serum eyedrops, rich in growth factors and anti-inflammatory substances, have demonstrated significant improvements in tear film stability and subjective symptoms.⁴

Conclusion

DED is a multifactorial condition that affects individuals of all ages. While age remains a significant risk factor, a myriad of other factors, including lifestyle, gender, ethnicity, genetics, comorbidities, and societal influences, contribute to its development. Recognising these diverse risk factors and implementing appropriate management strategies, such as artificial tears, is crucial in alleviating the symptoms and improving the QoL for individuals living with DED.

References

1. Stapleton F, et al. TFOS lifestyle: Impact of societal challenges on the ocular surface. Ocul Surf, 2023.
2. Messmer EM. The pathophysiology, diagnosis, and treatment of dry eye disease. Dtsch Arztebl Int, 2015.
3. Akowuah PK, Kobia-Acquah E. Prevalence of Dry Eye Disease in Africa: A Systematic Review and Meta-analysis. Optom Vis Sci, 2020.
4. Semp DA, Beeson D, Sheppard AL, Dutta D, Wolffsohn JS. Artificial Tears: A Systematic Review. Clin Optom (Auckl), 2023.