Impact of Diquafosol Ophthalmic Solution on Tear Film and Dry Eye Symptom in Type 2 Diabetic Dry Eye: A Four-week Randomized Control, Single Masked Pilot Study.

This study will be conducted in compliance with the tenets of the Declaration of Helsinki and the Institutional Review Board of He Eye Specialist Hospital, Shenyang, China (approval number: IRB2019.K002.01).

Type 2 diabetes mellitus (T2DM) is a prevalent chronic metabolic illness that causes relative insulin insufficiency in target organs owing to pancreatic β-cell dysfunction and insulin resistance [1]. Shift to sedentary lifestyle, ageing population and obesity has significantly contributed to the global rise in the prevalence of T2DM [2]. In 2019 the prevalence of diabetes was documented to be 9.3% (463 million people) and in 2030 it is estimated to rise to 10.2% (578 million) and T2DM accounts for approximately 90% of all diabetic occurrence[3]. Negative alterations to the tear film, corneal epithelium, corneal endothelium, and corneal nerves have been observed in 47-64% of patients with diabetes[4] [5]. Ocular surface manifestation of signs and symptoms secondary to DM has been termed as diabetic keratopathy (DK). DK has been documented to increase central corneal thickness[6], decrease in endothelial cell density[7], leads of superficial punctate keratitis[8], delay and impede wound repair[9], and decrease in corneal sensitivity due to neuropathy[10]. Additionally, DM patients have also been noted to have compromised tear quantity and quality[11][12] due to conjunctival goblet cell loss as documented on cytologic analysis [13]. Goblet cells secrete mucin, which stabilizes the tear film, minimizes tear evaporation, and reduces mechanical friction. Goblet cell loss in animal models suggests that it disrupts the ocular surface's immune tolerance [14] and increased expression of inflammatory cytokines in the conjunctiva[15]. 0.1% hyaluronate (HA) used in artificial tears have been reported to promote corneal re-epithelium and improve corneal healing[16].

Additionally, HA has been reported to decrease the rate of tear evaporation and enhance the stability of tear film [17]. Diquafosol tetrasodium is a dinucleotide polyphosphate which a purinoceptor agonist, when administered to the ocular surface, it binds to P2Y2 receptors and stimulates mucin and tear secretion[18-20]. The corneal epithelium, conjunctival epithelium, lacrimal gland ductal epithelium, meibomian gland sebaceous cells, and meibomian gland ductal cells all express the P2Y2 receptor. [21,22]. Subsequently, enhanced secretion of mucin and tear secretion due to Diquafosol tetrasodium ophthalmic solution (DQS) stabilize the tear film, minimizes tear evaporation, and reduces mechanical friction thereby protecting the corneal epithelium [23]. Various reports have concluded that that 3% DQS is effective in the treatment of dry eye disease [24-26] and Dota et al.'s [19] findings suggest that DQS improves corneal epithelial damage in T2DM rat model.

However, the effect of DQS on the tear film of T2DM humans has not been previously assessed. Therefore, the purpose s to assess subjective and objective diabetic dry eye findings after using 3% DQS or 0.1% HA topical eye drops.