December 2022

PURPOSE: To evaluate agreement of nonmydriatic confocal scanning laser ophthalmoscopy (SLO; EIDON [CenterVue]) and the 7-standard field ETDRS area on ultrawide-field (UWF) SLO imaging for identification of diabetic retinopathy (DR) severity. DESIGN: Single-site, prospective, comparative, instrument validation study. PARTICIPANTS: One hundred ten eyes of 55 patients with diabetes mellitus were evaluated. METHODS: Each patient underwent nonmydriatic, nonsimultaneous stereoscopic imaging using the EIDON camera and 4 fields of 60° × 55° were acquired (macula centered, disc centered, temporal macula, superotemporal). Mydriatic UWF retinal images were acquired using a nonsimultaneous stereographic protocol with UWF imaging (California; Optos plc). Before grading, a standardized ETDRS 7-field image mask was applied to all UWF retinal images. Images from each device were graded independently by 2 masked graders using the ETDRS clinical DR classification. Any discrepancy in DR grading between the devices was adjudicated by a third grader. MAIN OUTCOME MEASURES: κ Levels of agreement, sensitivity, and specificity for DR thresholds. RESULTS: Severity by ETDRS grading was as follows: no DR, 10.9%; mild nonproliferative DR (NPDR), 45.5%; moderate NPDR, 16.5%; severe NPDR, 11.8%; proliferative DR, 12.7%; high-risk proliferative DR, 2.7%; and ungradable, 0%. After adjudication, the level of DR identified on EIDON images agreed exactly with that of UWF ETDRS imaging in 87% of eyes (n = 96) and was within 1 step in 99.1% of eyes (n = 109) with a simple κ value of 0.8244 ± 0.0439 (95% confidence interval [CI], 0.7385-0.9104) and weighted (linear) κ value of 0.9041 ± 0.0257 (95% CI, 0.8537-0.9545). Sensitivity and specificity compared with ETDRS field grading for any DR were 0.96 and 0.75, for moderate NPDR or worse were 0.96 and 0.97, and for severe NPDR or worse were 0.91 and 1.00, respectively. CONCLUSIONS: Nonmydriatic 4-field stereoscopic widefield imaging using the EIDON device was comparable with the DR severity identified within the ETDRS 7-standard field area of UWF images. Future studies will need to evaluate the applicability of this device as a clinical and research tool and the impact of different widefield coverage areas.

OBJECTIVE: To describe the relationships between the cumulative incidences of long-term complications in individuals with type 1 diabetes (T1D) and assess whether observed associations are independent of age, duration of diabetes, and glycemic levels. METHODS: Proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), reduced estimated glomerular filtration rate (eGFR), amputations, cardiovascular disease (CVD), and mortality were assessed in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study over ∼30 years. RESEARCH DESIGN AND RESULTS: The cumulative incidence of complications ranged from 3% (amputations) to 37% (CSME). There were large differences in the cumulative incidence of PDR between participants with versus without prior CSME (66% vs. 15%), reduced eGFR (59% vs. 29%), and amputation (68% vs. 32%); reduced eGFR with or without prior PDR (25% vs. 9%), amputation (48% vs. 13%), and CVD (30% vs. 11%); CVD with or without prior reduced eGFR (37% vs. 14%) and amputation (50% vs. 16%); and mortality with or without prior reduced eGFR (22% vs. 9%), amputation (35% vs. 8%), and CVD (25% vs. 8%). Adjusted for age, duration of T1D, and mean updated HbA1c, the complications and associations with higher risk included PDR with CSME (hazard ratio [HR] 1.88; 95% CI 1.42, 2.50), reduced eGFR (HR 1.41; 95% CI 1.01, 1.97), and CVD (HR 1.43; 95% CI 1.06, 1.92); CSME with higher risk of PDR (HR 3.94; 95% CI 3.18 4.89), reduced eGFR (HR 1.49; 95% CI 1.10, 2.01), and CVD (HR 1.35; 95% CI 1.03, 1.78); reduced eGFR with higher risk of CVD (HR 2.09; 95% CI 1.44, 3.03), and death (HR 3.40; 95% CI 2.35, 4.92); amputation(s) with death (HR 2.97; 95% CI 1.70, 2.90); and CVD with reduced eGFR (HR 1.59; 95% CI 1.08, 2.34) and death (HR 1.95; 95% CI 1.32, 2.90). CONCLUSIONS: Long-term micro- and macrovascular complications and mortality are highly correlated. Age, diabetes duration, and glycemic levels do not completely explain these associations.

Infectious uveitis is a sight-threatening infection commonly caused by herpesviruses. Vitreous humor is often collected for molecular confirmation of the causative agent during vitrectomy and mixed in large volumes of buffered saline, diluting the pathogen load. Here, we explore affinity-capture hydrogel particles (Nanotrap®) to concentrate low abundant herpesviruses from diluted vitreous. Simulated samples were prepared using porcine vitreous spiked with HSV-1, HSV-2, VZV and CMV at 105 copies/mL. Pure undiluted samples were used to test capturing capability of three custom Nanotrap particles (red, white and blue) in a vitreous matrix. We found that all particles demonstrated affinity to the herpesviruses, with the Red Particles having both good capture capability and ease of handling for all herpesviruses. To mimic diluted vitrectomy specimens, simulated-infected vitreous were then serially diluted in 7 mL TE buffer. Diluted samples were subjected to an enrichment protocol using the Nanotrap Red particles. Sensitivity of pathogen detection by qPCR in diluted vitreous increased anywhere between 2.3 to 26.5 times compared to non-enriched specimens. This resulted in a 10-fold increase in the limit of detection for HSV-1, HSV-2 and VZV. These data demonstrated that Nanotrap particles can capture and concentrate HSV-1, HSV-2, VZV and CMV in a vitreous matrix.

Candida species are the most common causes of sight-threatening fungal ocular infections in temperate regions of the world. Despite their relevance, little is known about the emergence of novel species and the molecular epidemiology of these infections. Here we molecularly characterized 38 yeast isolates collected from patients diagnosed with endophthalmitis or keratitis at Massachusetts Eye and Ear from 2014-2021. Sequencing of the ITS1-5.8S-/ITS2 regions demonstrated that this population of yeasts was dominated by Candida spp. (37 out of 38; 97%), with 58% of the cases caused by C. albicans (n = 22), and the remaining by emerging non-albicans species, predominantly by C. parapsilosis (n = 8) and C. dubliniensis (n = 6). One isolate each was identified as C. tropicalis and Clavispora lusitaniae. Interestingly, all C. dubliniensis were isolated from endophthalmitis and most C. parapsilosis from keratitis. MLST analysis of C. albicans showed a prevalence of CC-1 isolates that has DST69 as the putative founder, with 64% of them belonging to this clonal complex. Isolates grouped within this cluster were more predominant in endophthalmitis (10 out of 14; 71%). One C. albicans CC-1 isolate was multi-azole resistant. In conclusion, we observed that nearly half of the ocular infections caused by yeasts are associated with C. albicans, with evidence for the emergence of non-albicans species that are differentially enriched in distinct ocular niches. Candida albicans isolates clustered within the predominant CC-1 group were particularly more common in endophthalmitis, demonstrating a potential pattern of ocular disease enrichment within this clade.

PURPOSE: To determine prevalence of probable polypoidal choroidal vasculopathy (PCV) among White patients with neovascular age-related macular degeneration (nAMD) using non-indocyanine green angiography (ICGA) criteria DESIGN: Multicenter, multinational, retrospective, cross-sectional study. METHODS: A total of 208 treatment-naive eyes from Hispanic and non-Hispanic White individuals diagnosed with nAMD were included. All underwent color fundus photography (CFP), optical coherence tomography (OCT), and fluorescein angiography (FFA). De-identified images of study eyes were sent to 2 groups of graders. Group 1 reviewed CFP, OCT, and FFA to confirm nAMD diagnosis. Group 2 reviewed CFP and OCT to determine highly suggestive features for PCV. Probable PCV diagnosis defined as the presence of ≥2 of 4 highly suggestive features for PCV: notched or fibrovascular pigment epithelial detachment (PED) on CFP, sharply-peaked PED, notched PED, and hyperreflective ring on OCT. RESULTS: Eleven eyes were excluded because of poor image quality (6) or non-nAMD diagnosis (5). Of 197 eligible eyes (197 patients), the mean age (SD) was 78.8 years (8.9), 44.2% were men, 26.4% were Hispanic, and 73.6% were non-Hispanic White individuals; 41.1%, 23.4%, 9.1%, and 2.5% had ≥1, ≥2, ≥3, and 4 highly suggestive features. Results showed that 23.4% (95% CI, 17.6%-29.9%) had probable PCV diagnosis. Predominantly occult CNV was more frequently found in probable PCV than nAMD subgroup (84.8% vs 64.9%, P = .01). Hispanic White individuals had a lower prevalence of probable PCV than non-Hispanic White individuals (9.6% vs 28.2%, P = .006) CONCLUSIONS: These findings suggest that probable PCV occurs between 17.6% and 29.9% in White individuals with nAMD, and more commonly in non-Hispanic than in Hispanic White individuals.

This study aimed to develop a miltefosine-eluting contact lens (MLF-CL) device that would allow sustained and localized miltefosine release for the treatment of Acanthamoeba keratitis. MLF-CLs were produced in three different miltefosine doses by solvent-casting a thin miltefosine-polymer film around the periphery of a methafilcon hydrogel, which was then lathed into a contact lens. During seven days of in vitro testing, all three formulations demonstrated sustained release from the lens at theoretically therapeutic levels. Based on the physicochemical characterization of MLF-CLs, MLF-CL's physical properties are not significantly different from commercial contact lenses in terms of light transmittance, water content and wettability. MLF-CLs possessed a slight reduction in compression modulus that was attributed to the inclusion of polymer-drug films but still remain within the optimal range of soft contact lenses. In cytotoxicity studies, MLF-CL indicated up to 91% viability, which decreased proportionally as miltefosine loading increased. A three-day biocompatibility test on New Zealand White rabbits revealed no impact of MLF-CLs on the corneal tissue. The MLF-CLs provided sustained in vitro release of miltefosine for a week while maintaining comparable physical features to a commercial contact lens. MLF-CL has a promising potential to be used as a successful treatment method for Acanthamoeba keratitis.

PURPOSE: To evaluate the prevalence of retinal disease on fluorescein angiography (FA) in patients with incontinentia pigmenti (IP) and to compare the severity of retinal disease in those with and without known central nervous system (CNS) disease. DESIGN: Multi-institutional consecutive retrospective case series. SUBJECTS: New patients with a diagnosis of IP were seen at the Casey Eye Institute at the Oregon Health and Science University (OHSU), Moran Eye Center, University of Utah, or Bascom Palmer Eye Institute, University of Miami from December 2011 to September 2018. METHODS: Detailed ophthalmoscopic examination and FA were recommended for all new patients and performed on every patient who had parental consent. Ophthalmoscopic findings and FA images were graded for severity by 2 masked graders on a 3-point scale: 0 = no disease, 1 = vascular abnormalities without leakage, 2 = leakage or neovascularization, and 3 = retinal detachment. The presence of known CNS disease was documented. Additional cases were obtained from a pediatric retina listserv for examples of phenotypic variation. MAIN OUTCOME MEASURES: The proportion of eyes noted to have disease on ophthalmoscopy compared with FA and the severity of retinal disease in those with and without known CNS disease. RESULTS: Retinal pathology was detected in 18 of 35 patients (51%) by indirect ophthalmoscopy and 26 of 35 patients (74%) by FA (P = 0.048) in a predominantly pediatric population (median age, 9 months). Ten patients (29%) had known CNS disease at the time of the eye examination. A Wilcoxon rank-sum test indicated that the retinal severity scores for patients with CNS disease (median, 2) were significantly higher than the retinal severity scores for patients without CNS disease (median, 1), z = -2.12, P = 0.034. CONCLUSIONS: Retinal disease is present in the majority of patients with IP, and ophthalmoscopic examination is less sensitive than FA for detection of disease. There may be a correlation between the severity of retinal and CNS disease.

PURPOSE: To present a literature review on various immunopathologic dysfunctions following COVID-19 infection and their potential implications in development of rhino-orbital-cerebral mucormycosis (ROCM). METHODS: A literature search was performed via Google Scholar and PubMed with subsequent review of the accompanying references. Analogies were drawn between the immune and physiologic deviations caused by COVID-19 and the tendency of the same to predispose to ROCM. RESULTS: Sixty-two articles were reviewed. SARS-CoV-2 virus infection leads to disruption of epithelial integrity in the respiratory passages, which may be a potential entry point for the ubiquitous Mucorales to become invasive. COVID-19 related GRP78 protein upregulation may aid in spore germination and hyphal invasion by Mucorales. COVID-19 causes interference in macrophage functioning by direct infection, a tendency for hyperglycemia, and creation of neutrophil extracellular traps. This affects innate immunity against Mucorales. Thrombocytopenia and reduction in the number of natural killer (NK) cells and infected dendritic cells is seen in COVID-19. This reduces the host immune response to pathogenic invasion by Mucorales. Cytokines released in COVID-19 cause mitochondrial dysfunction and accumulation of reactive oxygen species, which cause oxidative damage to the leucocytes. Hyperferritinemia also occurs in COVID-19 resulting in suppression of the hematopoietic proliferation of B- and T-lymphocytes. CONCLUSIONS: COVID-19 has a role in the occurrence of ROCM due to its effects at the entry point of the fungus in the respiratory mucosa, effects of the innate immune system, creation of an environment of iron overload, propagation of hyperglycemia, and effects on the adaptive immune system.

Proliferative vitreoretinopathy (PVR) is a fibrotic eye disease that develops after rhegmatogenous retinal detachment surgery and open-globe traumatic injury. Idelalisib is a specific inhibitor of phosphoinositide 3-kinase (PI3K) δ. While PI3Kδ is primarily expressed in leukocytes, its expression is also considerably high in retinal pigment epithelial (RPE) cells, which play a crucial part in the PVR pathogenesis. Herein we show that GeoMx Digital Spatial Profiling uncovered strong expression of fibronectin in RPE cells within epiretinal membranes from patients with PVR, and that idelalisib (10 μM) inhibited Akt activation, fibronectin expression and collagen gel contraction induced by transforming growth factor (TGF)-β2 in human RPE cells. Furthermore, we discovered that idelalisib at a vitreal concentration of 10 μM, a non-toxic dose to the retina, prevented experimental PVR induced by intravitreally injected RPE cells in rabbits assessed by experienced ophthalmologists using an indirect ophthalmoscope plus a + 30 D fundus lens, electroretinography, optical coherence tomography and histological analysis. These data suggested idelalisib could be harnessed for preventing patients from PVR.

PURPOSE: To evaluate the efficacy of topical netarsudil 0.02% as adjunctive therapy in children with refractory pediatric glaucoma. METHODS: The medical records of patients ≤18 years diagnosed with pediatric glaucoma treated with topical netarsudil 0.02% from June 2019 to March 2022 were reviewed retrospectively. Data collected included age, sex, ethnicity, etiology of glaucoma, history of previous or subsequent glaucoma surgery, and intraocular pressure (IOP) before and after the addition of topical netarsudil. RESULTS: A total of 21 eyes of 16 patients (11 males) were included. Five patients used topical netarsudil in both eyes. Eight patients were Hispanic. The mean number of glaucoma surgeries and medications before initiating topical netarsudil was 1.8 ± 1.2 and 3.7 ± 0.5, respectively. The mean age prior to starting topical netarsudil was 8.9 ± 4.1 years. The mean follow-up after initiating topical netarsudil was 11.3 ± 8.2 months. The IOP was significantly reduced from 26.3 ± 6.2 mm Hg before topical netarsudil to 19.6 ± 6.02 mm Hg at 1 month in 15 eyes (P < 0.01), 18.2 ± 6.9 mm Hg at 3-months in 18 eyes (P < 0.01), 18.3 ± 7.3 mm Hg at 6 months in 13 eyes (P = 0.01), 17.6 ± 5.07 mm Hg at 9 months in 14 eyes (P = 0.002), and 17.4 ± 3.1 mm Hg at 12 months in 13 eyes (P = 0.002). Nine eyes (43%) underwent additional glaucoma surgery due to long-term failure of topical netarsudil to reduce IOP despite an initial reduction, and one eye had persistent IOP elevation ≥21 mm Hg despite the addition of topical netarsudil. CONCLUSIONS: In our small cohort of patients with refractory pediatric glaucoma, the addition of topical netarsudil reduced IOP, potentially delaying the need for surgery.

PURPOSE: Secreted protein acidic and rich in cysteine (SPARC) is a matricellular glycoprotein abundantly expressed in basement membranes and capsules surrounding a variety of organs and tissues. It mediates extracellular matrix organization and has been implicated in cell contraction. Here, we evaluated the expression of SPARC in the murine lacrimal gland at adulthood and during inflammation. METHODS: Lacrimal glands of young mice (4-6 weeks old) and adult mice (32-40 weeks old) were used for extraction of DNA, RNA, and protein. The presence of SPARC was assessed by quantitative PCR, ELISA, and immunofluorescence microscopy. 5-Methylcytosine and DNA methylation were evaluated using ELISA and bisulfite genomic sequencing, respectively. The effects of cytokines and inflammation in Sparc expression were evaluated in vitro and in the non-obese diabetic (NOD) mouse model of Sjögren's syndrome. RESULTS: The mRNA and protein levels of SPARC were downregulated in lacrimal glands of mature adult mice presenting age-related histological alterations such as increased deposition of lipofuscin and lipids. Epigenetic analyses indicated that glands in adult mice contain higher levels of global DNA methylation and show increased hypermethylation of specific CpG sites within the Sparc gene promoter. Analysis of smooth muscle actin (SMA)-green fluorescent protein (GFP) transgenic mice revealed that SPARC localizes primarily to myoepithelial cells within the gland. Treatment of myoepithelial cells with IL-1β or TNF-α and the development of inflammation in the NOD mice led to decreased transcription of Sparc. CONCLUSIONS: SPARC is a novel matricellular glycoprotein expressed by myoepithelial cells in the lacrimal gland. Loss of SPARC during adulthood and chronic inflammation might have detrimental consequences on myoepithelial cell contraction and the secretion of tear fluid.

BACKGROUND: Visual display terminal (VDT) use is a key risk factor for dry eye disease (DED). Visual display terminal (VDT) use reduces the blink rate and increases the number of incomplete blinks. However, the exact mechanisms causing DED development from VDT use have yet to be clearly described. PURPOSE: The purpose of the study was to conduct a review on pathophysiological mechanisms promoting VDT-associated DED. METHODS: A PubMed search of the literature investigating the relationship between dry eye and VDT was performed, and relevance to pathophysiology of DED was evaluated. FINDINGS: Fifty-five articles met the inclusion criteria. Several pathophysiological mechanisms were examined, and multiple hypotheses were extracted from the articles. Visual display terminal (VDT) use causes DED mainly through impaired blinking patterns. Changes in parasympathetic signalling and increased exposure to blue light, which could disrupt ocular homeostasis, were proposed in some studies but lack sufficient scientific support. Together, these changes may lead to a reduced function of the tear film, lacrimal gland, goblet cells and meibomian glands, all contributing to DED development. CONCLUSION: Visual display terminal (VDT) use appears to induce DED through both direct and indirect routes. Decreased blink rates and increased incomplete blinks increase the exposed ocular evaporative area and inhibit lipid distribution from meibomian glands. Although not adequately investigated, changes in parasympathetic signalling may impair lacrimal gland and goblet cell function, promoting tear film instability. More studies are needed to better target and improve the treatment and prevention of VDT-associated DED.

PURPOSE: Estimates of diabetic eye disease in American Indian and Alaska Natives (AI/AN) vary over time, region, and methods. This article reports recent prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME) in AI/AN served by the Indian Health Services' (IHS) teleophthalmology program, as identified using ultrawide field imaging (UWFI). METHODS: This was a retrospective analysis of 2016-2019 clinical data (n = 53,900). UWF images were acquired by certified imagers using a validated protocol, and graded by licensed, certified optometrists supervised by an ophthalmologist. Graders evaluated the extent/severity of retinal lesions in comparison to standard photographs. DR lesions predominantly in any peripheral field were considered "predominantly peripheral lesions" (PPL). The analyses calculated prevalence of any DR, any DME, DR and DME severity, sight-threatening disease, and PPL. RESULTS: Patients averaged 56 years of age with a 68 mmol/mol A1c and 55% had had diabetes for 5+ years. Prevalence of any DR, any DME, and sight-threatening disease was 28.6%, 3.0%, and 3.0%. In patients with mild nonproliferative DR, PPL was seen in 25.3%. PPL suggested a more severe level of DR in 8.7% of patients. DR increased with age. DME decreased with age. Males and patients in the Nashville IHS area had more diabetic eye disease. CONCLUSION: AI/AN have a high burden of diabetes and its complications. The IHS is resource-constrained, making accurate disease estimates necessary for resource allocation and budget justifications to Congress. These data update the estimates of diabetic eye disease in Indian Country and suggest that UWFI identifies early DR.

Management of pediatric choroidal hemangioma complicated by large exudative retinal detachment can be challenging, with few options available. Limited data have been published on outcomes following proton radiotherapy (PRT) for management of these patients. In this retrospective case series, nine patients were treated with a low-dose PRT regimen of 20 Gy(relative biological effectiveness [RBE]) in 10 fractions, and two were treated with 15 Gy(RBE) in four fractions. Visual acuity improved in seven patients (64%) and remained stable in the remaining four (36%). In patients with imaging follow-up (10 patients), subretinal fluid resolved in nine patients (90%) and tumor thickness decreased or remained stable in 10 (100%). Complications were observed in eight of 11 patients (73%). One patient developed grade 2 cataract; otherwise, no grade ≥2 complications were observed.

Glaucoma is a highly heritable disease that is a leading cause of blindness worldwide. Here, we identified heterozygous thrombospondin 1 (THBS1) missense alleles altering p.Arg1034, a highly evolutionarily conserved amino acid, in 3 unrelated and ethnically diverse families affected by congenital glaucoma, a severe form of glaucoma affecting children. Thbs1R1034C-mutant mice had elevated intraocular pressure (IOP), reduced ocular fluid outflow, and retinal ganglion cell loss. Histology revealed an abundant, abnormal extracellular accumulation of THBS1 with abnormal morphology of juxtacanalicular trabecular meshwork (TM), an ocular tissue critical for aqueous fluid outflow. Functional characterization showed that the THBS1 missense alleles found in affected individuals destabilized the THBS1 C-terminus, causing protein misfolding and extracellular aggregation. Analysis using a range of amino acid substitutions at position R1034 showed that the extent of aggregation was correlated with the change in protein-folding free energy caused by variations in amino acid structure. Extracellular matrix (ECM) proteins, especially fibronectin, which bind to THBS1, also accumulated within THBS1 deposits. These results show that missense variants altering THBS1 p.Arg1034 can cause elevated IOP through a mechanism involving impaired TM fluid outflow in association with accumulation of aggregated THBS1 in the ECM of juxtacanalicular meshwork with altered morphology.

A 77-year-old Asian female with a history of left orbit exenteration and lid-sparing reconstruction for recurrent sebaceous carcinoma presented with fluid-like sensation of the left orbit. Magnetic resonance imaging (MRI) demonstrated bright T2 signal and a cyst-like cavity within the exenterated orbit. Decision was made to proceed with surgical exploration and excision. A calcified, bone-like cavity was encountered intraoperatively and removed. Histopathology revealed dense fibrous connective tissue with areas of calcification without osseous metaplasia, suggestive of retained blood in the orbit that underwent dystrophic calcification. This case report illustrates a rare occurrence of a bone-like calcific cyst following exenteration.

Dry eye disease (DED) is a highly prevalent and debilitating condition affecting several hundred million people worldwide. Hyaluronic acid (HA) is a naturally occurring glycosaminoglycan commonly used in the treatment of DED. This review aims to critically evaluate the literature on the safety and efficacy of artificial tears containing HA used in DED treatment. Literature searches were conducted in PubMed, including MEDLINE, and in Embase via Ovid with the search term: "(hyaluronic acid OR hyaluronan OR hyaluronate) AND (dry eye OR sicca)". A total of 53 clinical trials are included in this review, including eight placebo-controlled trials. Hyaluronic acid concentrations ranged from 0.1% to 0.4%. Studies lasted up to 3 months. A broad spectrum of DED types and severities was represented in the reviewed literature. No major complications or adverse events were reported. Artificial tears containing 0.1% to 0.4% HA were effective at improving both signs and symptoms of DED. Two major gaps in the literature have been identified: 1. no study investigated the ideal drop frequency for HA-containing eyedrops, and 2. insufficient evidence was presented to recommend any specific HA formulation over another. Future investigations assessing the optimal drop frequency for different concentrations and molecular weights of HA, different drop formulations, including tonicity, and accounting for DED severity and aetiology are essential for an evidence-based, individualized approach to DED treatment.