Role of oral bio-enhanced curcumin in dry eye disease

Abstract

Purpose:

To assess the role of oral bio-enhanced curcumin in dry eye disease (DED).

Design:

Randomized, double-masked, placebo-controlled clinical study conducted at a tertiary eye center.

Methods:

Forty patients of bilateral mild to moderate DED were randomized in two groups – group A (topical carboxy methyl cellulose QID + oral placebo) and group B (topical carboxy methyl cellulose QID + oral bio-enhanced curcumin). The objective parameters of DED were quantified at baseline and compared at 3 months follow-up.

Results:

At three months follow-up, there was significant improvement in curcumin group in terms of Ocular Surface Disease Index (OSDI) score (P = 0.002), tear meniscus height (TMH) (P = 0.002), tear volume (P = 0.006), tear break-up time (TBUT) (P < 0.001), non-invasive break-up time (NIBUT) (P = 0.026), lipid layer thickness (LLT) (P = 0.01), and decrease in bulbar redness (P = 0.002). There was no significant improvement in limbal redness (P = 0.097), corneal-staining score (P = 0.93), and Schirmer’s test (P = 0.42). Mild adverse drug reaction was observed in three cases of the curcumin group and one case of group A.

Conclusions:

Oral bio-enhanced curcumin is a safe and effective treatment modality in cases of mild to moderate DED. It effectively improves the tear film stability, LLT, and TMH and reduces the bulbar redness.

Dry eye disease (DED) is a multifactorial disorder with underlying chronic ocular surface inflammation.[1] The mainstay of DED therapy involves instillation of lubricant eye drops to provide temporary symptomatic relief and treating the underlying inflammation to break the cascade of DED. The two main classes of topical anti-inflammatory agents, corticosteroids, and immunomodulators are currently used for DED management. Corticosteroids target ocular surface inflammation, but their potential long-term adverse effects include cataracts and steroid-induced glaucoma. This limits their use to control the acute exacerbation episodes. Topical cyclosporin A is a fungal antimetabolite that is used as a topical immunomodulator to inhibit interleukin-induced activation of lymphocytes.

Novel oral supplements and therapies offer alternative anti-inflammatory effects on the eye modulating systemic cytokine production. One of these is oral curcumin which is being increasingly investigated in the treatment of eye conditions, showing potential value in the treatment of several ocular disorders. Curcumin is a major phytochemical isolated from the plant Curcuma longa and is the principal curcuminoid of the popular spice turmeric which has been extensively used as a coloring agent in South Asian countries.[2]

DED is associated with increased tear osmolality and inflammation of the ocular surface. Presence of proinflammatory cytokines like interleukins (IL) IL-6, IL-8, and IL-1β has been observed in corneal cells and in patients with DED in hyperosmotic conditions. Curcumin exhibits potential protective effects due to its anti-inflammatory properties and anti-allergic properties.[3] The role of curcumin has been studied in various inflammatory diseases of the eye, including DED, conjunctivitis, pterygium, corneal neovascularization, corneal wound healing, cataract, anterior uveitis, age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy.[4] Additionally, its role in slowing down the inflammatory process in retinal diseases like proliferative vitreoretinopathy and AMD has been studied.[5]

However, the oral usage of curcumin is associated with a few adverse effects like gastroesophageal reflux, nausea, diarrhea, and dizziness. In addition to it, another limitation of the usage of oral curcumin is the inadequate bioavailability of oral curcumin to ocular tissues due to intestinal metabolism. Considering the ophthalmic penetration of the drug, the concentration that reaches the ocular tissue is quite low. Novel drug delivery systems like the inclusion of phospholipids as bioenhancers, encapsulation in liposomes, and inclusion of components like piperine and cyclodextrin result in improved uptake and absorption.[6] The bio-enhanced formulation of curcumin micronizes curcumin with additional turmeric essential oils and has greater bioavailability, improved pharmacokinetic profile, and increased efficacy. However, the role of oral bio-enhanced curcumin as a therapeutic option in cases of DED has not been explored in the past. This prospective pilot study was conducted with the aim to assess the role of bio-enhanced curcumin in cases of DED as there are limited studies in the literature which assess the efficacy of oral bio-enhanced curcumin in dry eye disease.

Methods

This was a randomized, double-masked, placebo-controlled study conducted at a tertiary eye center from May 2021 to August 2022. The study was approved by the institute ethical committee (IECPG-134/24.02.2021) and registered with the Clinical Trials Registry – India (CTRI/2022/01/039537). It was conducted in accordance with the tenets of the Declaration of Helsinki.

It included 40 patients of bilateral mild to moderate DED who presented to outpatient department (OPD). Both eyes were tested for all clinical parameters; however, for analysis, the right eye parameters were recorded and considered. The diagnosis of mild to moderate (non-severe) DED was based on objective criteria – tear break-up time (TBUT) <10 s and Schirmer’s one test > 5 mm. The patients of DED with age ≥ 18 years, best corrected visual acuity ≥ 20/40, and IOP ≤ 21 mm Hg in both eyes who were willing to participate and follow up in the study were included. The cases with diabetes mellitus, history of consuming oral curcumin supplements in the past three months before enrollment, recent contact lens wear, any systemic medication (including over-the-counter, herbal, prescription, or nutritional supplements) which may affect tear film, Sjogrens, or autoimmune diseases, presence of any of any active ocular infection, inflammation or allergy, severe blepharitis, and occluded lacrimal puncta were excluded.

Randomization

The eligible patients were randomized to intervention and placebo groups on 1:1 basis. Block randomization was performed in Microsoft (MS) Excel creating blocks of 4. Opaque, sealed envelopes containing a treatment allocation namely “A” or “B” were kept in a box in OPD and were allocated to each patient in sequence. This randomized sequence was prepared using MS Excel. Participants were assigned to one of two arms: group A: placebo group (Roasted rice powder was used as capsules) and topical lubricant (CMC); group B: active drug supplement group (Bio-enhanced curcumin tablets) and topical lubricant (CMC). The bio-enhanced curcumin capsules were the same as the BCM-95 formulation of bio-enhanced curcumin.

Blinding

The placebo capsules were also prepared by the same manufacturer ensuring same external appearance of the capsule in terms of color and size making both groups indistinguishable from the outside. They were handed over the formulations as “A” and “B” in a transparent plastic boxes to the OPD team.

Both groups consumed the assigned tablets of 500 mg twice a day (BD dosage) for 90 days. Participants were masked to treatment allocation, as achieved by all investigational products being dispensed in identical opaque containers; all participants also consumed the same number of capsules per day. All study personnel, including the principal investigator, clinical outcome assessor, laboratory outcome assessors, and co-investigators, were masked to participant allocation. Following the completion of all participant visits, data were analyzed only with knowledge of the simple randomization code (i.e. group A and B allocation). Full unmasking of treatment allocation by the provider only occurred after statistical analyses were complete [Fig. 1].

Figure 1.

CONSORT diagram showing the study methodology

Procedure

A detailed history was taken including information on treatment history. Symptom assessment using a validated 12-item OSDI scoring system which assesses symptoms of ocular discomfort, effects on visual function, and the impact of environmental triggers was done. The ocular examination included best corrected visual acuity (BCVA), anterior segment evaluation using a slit lamp, assessment of intraocular pressure, Schirmer’s one test, meniscometry using anterior segment optical coherence tomography (AS-OCT), Schirmer’s test, invasive TBUT using fluorescein stain, non-invasive TBUT and staining score. A change of > 5 s in TBUT was considered as responders. A decrease of NEI score by 5 was considered as responders. An improvement of test value of > 5 mm of wetting on Schirmer’s test at 5 min was considered as responders. The bulbar redness and limbal redness were graded on slit lamp using the validated Efron scales. Each parameter was assigned a grade, from 0.0 to 4.0, using increments of 0.1. Corneal-staining was assessed using National Eye Institute grading using sodium fluorescein stain in cobalt blue illumination. The patients were followed up at points: day 1 (presentation), day 30, day 60, and day 90.

Outcome parameters

The primary outcome measure was the mean change in OSDI score between day 1 and last follow-up. Secondary outcomes included mean change in tear meniscus height (TMH), Schirmer’s test, TBUT, non-invasive break-up time (NIBUT), lipid layer thickness (LLT), decrease in redness, staining score, and assessment of safety.

Sample size calculation

A target sample size of 20 participants per arm was targeted. A 25% change from baseline in OSDI score in the intervention group was assumed to be significant.[7] With a significance level of 0.05 and keeping the power of study at 90%, a target of 16 patients per group was calculated. A standard deviation of 30% was assumed. However, considering 20% participant attrition, an additional four participants per group were included, giving a recruitment target of 20 per group (n = 20 per group).

Statistical analysis

Analysis was performed using the intention to treat principle. Data were recorded in Microsoft Excel Spreadsheet. Data were expressed as median ± standard error, mean ± standard deviation, and percentage as applicable. Nominal data were compared using the Chi-square test or Fisher exact test, as appropriate. Non-parametric quantitative data were compared using Kruskal Wallis and Mann-Whitney U tests. One-way analysis of variance was used to compare intergroup means for parametric quantitative data, and Bonferroni correction was used to analyze post-test results.

Results

A total of 40 eyes of 40 patients (n = 40) were recruited in the study in two equal groups. Based on Schirmer’s test, the ratio of mild to moderate cases in group A and B was 8:12 and 10:10, respectively. Their results were summarized as sociodemographic and socioeconomic result, clinical results, and safety profile.

The mean age in group A was 31.7 ± 9.16 years, while in group B, it was 37.55 ± 14.54 years (P = 0.12). The percentage of male cases in group A was 55%, while in group B, it was 40%. The rest were female (P = 0.34). The group A had 90% urban population and 10% rural population, whereas group B had 80% urban population and 20% rural population (P = 0.78). Majority of cases in both groups belonged upper lower class (group A 65% and group B 55%) (P = 0.83) according to modified Kuppuswamy and Udai Pareekh’s scale.[8] Both the groups were comparable in terms of sociodemographic and socioeconomic terms.

There was no significant change in visual acuity and intraocular pressure from baseline to 3 months follow-up in both the groups. All baseline parameters have been enumerated in Table 1. The mean OSDI scores at recruitment and follow-up month and 3 months for group A studied were 51.5279 ± 14.55 and 42.2875 ± 12.19, respectively while for the group B, the mean OSDI scores at baseline and 3 months were 52.6180 ± 17.40 and 29.0480 ± 9.97, respectively. Based on the OSDI score, all cases were initially classified as severe DED (OSDI > 32). After 3 months of treatment, only three cases in the CMC group improved to a moderate grade of DED. In contrast, in the curcumin group, out of 20 cases, five improved to a mild grade, 10 improved to a moderate grade, while five remained at the severe grade. There was a statistically significant improvement in OSDI score at the end of 3 months (P = 0.002) [Fig. 2].

Table 1.

Baseline characteristics of both groups

Parameter		Group A (n=20)		Group B (n=20)		P
Visual acuity (log MAR)		0.1056±0.003		0.088±0.002		0.83
IOP (mm Hg)		13.9±2.6		13.9±2.29		0.98
OSDI		51.5279±14.55		52.6180±17.40		0.834
TMH		0.267±0.084		0.27±0.076		0.91
NEI score		7.05±1.50		7.91±1.663		0.79
LLT (nm)		56.3±22.29		54.45±21.8		0.79
Schirmer’s test (mm)		12.7±6.9		10.25±5.2		0.15
TBUT (seconds)		5.8±3.0		5.0±2.9		0.4
NIBUT (seconds)		8.26±1.73		8.24±2.17		0.97
Bulbar redness		2.10±0.553		2.30±0.85		0.259
Limbal redness		2.15±0.489		2.10±0.718		0.71

Figure 2.

Shows the decrease in OSDI score in both the groups from presentation to 3 months follow-up with a steeper drop in group B (curcumin group)

Tear volume was quantified using TMH. TMH values at baseline and 3 months for the placebo group were 0.267 ± 0.084 and 0.256 ± 0.065 mm, respectively, while for group B, it was 0.27 ± 0.076 and 0.33 ± 0.078 mm, respectively, at day 0 and 3 months. There was a significant improvement in TMH in group B at 3 months as compared to the placebo group (P = 0.006). The mean TBUT at recruitment and 3 months following intervention in group A was 5.8 ± 3.0 and 5 ± 1.9 s, while in group B, it was 5 ± 2.9 and 8.93 ± 2.8 s, respectively. Group B had significant improvement at the end of three months as compared to group A (P < 0.001). The NIBUT improved in group B at all subsequent follow-ups. On comparing the baseline values with those at the last follow-up, a significant improvement was observed (P = 0.026). The first significant intergroup difference was evident at 2 months in group B (curcumin) (8.56 ± 2.3 s), compared with placebo (7.97 ± 1.83 s), this effect was maintained in both groups at 3 months (9.04 ± 2.26 s vs 7.34 ± 1.65 s).

The mean values of LLT for group A at baseline and 3 months were 56.3 ± 22.29 nm and 50.25 ± 21.6 nm, respectively, while for group B, they were 54.45 ± 21.8 nm and 67.13 ± 16.9 nm, respectively. The LLT improved significantly in group B as compared to group A at 3 months (P = 0.011). The degree of limbal redness decreased in both the groups at 3 months follow-up. The decline in redness was greater in group B (2.10 ± 0.718 to 1.07 ± 0.458) as compared to group A (2.15 ± 0.489 to 1.44 ± 0.727), however, it could not reach statistical significance (P = 0.097). Similarly, the bulbar redness declined in both groups, but it was significantly less in group B (2.30 ± 0.85 to 1.00 ± 0.535) as compared to group A (2.10 ± 0.553 to 1.75 ± 0.683) (at the end of 3 months (P = 0.002).

The mean NEI corneal-staining scores at recruitment and 3 months following curcumin intervention were 7.91 ± 1.663, 8.72 ± 1.0, 7.65 ± 1.105, and 7.33 ± 1.113, respectively. In the placebo group, NEI corneal-staining scores were 7.05 ± 1.50 and 6 ± 1.54 at recruitment and 3 months, respectively. No significant difference or improvement in either of the two groups was observed (P = 0.93). The mean Schirmer’s test score at recruitment and 3 months following interventions in group A was 12.7 ± 6.9 and 13.8 ± 6.4 mm, respectively, while the mean Schirmer’s test values at recruitment month and 3 months following intervention in group B were 10.25 ± 5.2 and 15.5 ± 5.2 mm, respectively. Statistical analysis showed that P value was not significant at the end of 3^rd month (P = 0.42). All results at all follow-ups have been summarized in Table 2.

Table 2.

Highlights the results of all dry eye assessment parameters of the study

Parameter		Timepoint		Group A (n=20)		Group B (n=20)		P
OSDI		Baseline		51.5279±14.55		52.6180±17.40		0.002
		1 month		48.1505±14.22		43.6989±13.51
		2 month		47.0517±14.95		38.5618±14.03
		3 month		42.2875±12.19		29.0480±9.97
TMH (mm)		Baseline		0.267±0.084		0.27±0.076		0.006
		1 month		0.275±0.078		0.28±0.064
		2 month		0.250±0.084		0.32±0.071
		3 month		0.256±0.065		0.33±0.078
NEI		Baseline		7.05±1.50		7.91±1.663		0.93
		1 month		6.84±1.42		8.72±1.07
		2 month		6.78±1.4		7.65±1.105
		3 month		6±1.54		7.33±1.113
LLT (nm)		Baseline		56.3±22.29		54.45±21.8		0.01
		1 month		53±19.9		57±20.2
		2 month		51.39±18.9		59±19.7
		3 month		50.25±21.6		67.13±16.9
Schirmer’s test (mm)		Baseline		12.7±6.9		10.25±5.2		0.43
		1 month		13.5±6.8		11.3±5.3
		2 month		13.78±6.5		13.6±5.15
		3 month		13.8±6.4		15.5±5.2
TBUT (seconds)		Baseline		5.8±3.0		5.0±2.9		<0.001
		1 month		5.26±2.3		6.6±2.8
		2 month		5.44±2.15		8.29±3.1
		3 month		5±1.9		8.93±2.8
NIBUT (seconds)		Baseline		8.26±1.73		8.24±2.17		0.026
		1 month		8.33±1.86		8.37±2.5
		2 month		7.97±1.83		8.56±2.3
		3 month		7.34±1.65		9.04±2.26
Bulbar redness		Baseline		2.10±0.553		2.30±0.85		0.002
		1 month		2.15±0.745		1.56±0.705
		2 month		2.00±0.594		1.06±0.556
		3 month		1.75±0.683		1.00±0.535
Limbal redness		Baseline		2.15±0.489		2.10±0.718		0.097
		1 month		1.85±0.671		1.44±0.705
		2 month		1.50±0.707		1.06±0.556
		3 month		1.44±0.727		1.07±0.458

The number of cases which had adverse drug events were four (three in group A and one in group B). All instances of adverse events were mild. Two cases in group A experienced nausea, and one had bloating and heartburn, while in group B, one case had nausea. The number of cases having adverse effects was comparable in both the groups (P = 0.152). None of the cases in curcumin group and one case in placebo group discontinued the drug.

Discussion

The study included patients with mild to moderate DED divided in two groups that were comparable at presentation. Schirmer’s test along with TBUT was used for screening cases of DED. Schirmer’s test is subject to several factors and does not always yield repeatable results. TBUT is a sensitive and reliable criterion for diagnosing DED. A combination of two tests was used to minimize errors and exclude cases of severe aqueous deficiency. This is a limitation of the study; however, the tests were used, owing to their relevance in clinical assessment, ease to conduct, good diagnostic value, and cost-effectiveness for diagnosing DED in an outpatient department setting.[9] The mean age of both the groups in the study was in the 30s, emphasizing that the disease entity affects young individuals and may have an association with altered lifestyle and high screen time. The socioeconomic status of the study population was majorly affecting those from urban areas. This could be probably owing to a greater health-seeking behavior among the urban population coupled with greater usage of digital devices. The visual acuity and intraocular pressure in both groups were comparable at baseline and 3 months follow-up. The proportion of males and females in our study was comparable. As the study was conducted in a tertiary eye center, it does not reflect the prevalence of DED in a specific gender within the broader population of DED.

This study demonstrates the beneficial effects of curcumin in reducing Ocular Surface Disease Index (OSDI) in DED. At day 90, the mean OSDI score was reduced by an average of 23 units from baseline in the curcumin group, being statistically significant as compared to the placebo group (which improved on average by 9.24 units). Other nutritional supplements have also been studied based on improvement on OSDI scores. In a study by Kangari et al.,[10] oral consumption of omega-3 fatty acids was associated with a decrease in the rate of tear evaporation, an improvement in dry eye symptoms, and an increase in tear secretion. A similar study assessed the effect of two forms of oral long-chain ω-3 essential fatty acid supplementation in moderate DED. This study compared fish oil and krill oil against a placebo. At day 90, the OSDI score was reduced by an average of 19 units from baseline with krill oil supplementation, and 18 units from baseline with fish oil supplementation both being statistically different from the placebo group (which improved on average by 10.5 units).[7]

The Ocular Surface Disease Index (OSDI) evaluates the impact of ocular surface disease on a patient’s quality of life. As a patient-centered measure, it exhibits high sensitivity to change and employs a standardized set of questions, minimizing measurement bias. The OSDI encompasses comprehensive aspects, including symptom severity, environmental triggers, and their effects on daily activities. It has been evaluated as a valid and reliable objective criterion as an endpoint in clinical trials testing the efficacy of new treatments for DED.[11]

Curcumin also conferred significant improvement in tear film stability. The TBUT was increased in the curcumin group, reaching statistical significance on days 60 and 90 in comparison with the placebo group. On average, TBUT improved from 5 s at baseline to 8.9 s at the study endpoint in the curcumin group. Given that normal TBUT is 10 s or longer this degree of improvement is of major clinical significance and exceeds the criteria for a clinically important difference in TBUT (change of at least 30%).[12,13] The results were statistically significant, although the mean improvement in TBUT was 3.93 units from baseline. This implies that bio-enhanced curcumin group had better tear film stability than the control group. In the curcumin group, although the increase in TBUT is statistically significant, it is minute in terms of absolute units. Therefore, a study with a larger sample size, longer follow-up, and an assessment of tear inflammatory markers is needed to determine the clinical impact of oral bio-enhanced curcumin in DED. LLT has been correlated with the severity of DED in a study by Blackie et al.[14] Patients with severe DED have thinner lipid layers as compared to those with milder symptoms. This study also demonstrated improvement in LLT in patients of DED with curcumin supplementation as compared to a placebo. Although the study included only cases of mild to moderate DED, the LLT improved significantly in the curcumin group. Cases of DED with TBUT >10 s (false negatives of TBUT) may have been excluded in the study due to study inclusion criteria. This is one of the limitations of the study. In this study, there was a tendency of improvement in tear production with oral supplementation of curcumin in terms of Schirmer’s test; however, this could not achieve statistical significance. Tear volume was also quantified using TMH. Other studies too document a statistical improvement in Schirmer’s test, TMH, and other objective parameters of DED after administration of oral curcumin.[15,16]

The role of topical steroids has been evaluated in decreasing conjunctival hyperemia in cases of chronic DED. It was assessed using the Efron scale which quantified the reduction by 27.5% with topical corticosteroids vs 23.9% in the standard treatment group with no statistical difference between the two groups.[17] In this study, there was a significant decrease in the Efron score of the bulbar conjunctiva in the curcumin group. This suggests the anti-inflammatory action of oral curcumin. However, there are confounding factors associated with conjunctival hyperemia such as eye rubbing. The lack of assessment of these parameters is a limitation of the study.

Curcumin is known to possess anti-inflammatory, antioxidant, antimicrobial, hepatoprotective, immunostimulant, antiseptic, and antimutagenic properties. It is known to play an effective role in chronic inflammatory conditions such as rheumatic diseases, chronic kidney disease with hemodialysis, metabolic syndrome, rheumatoid arthritis, and cardiovascular diseases. It improves cellular health by impacting inflammatory markers like C-reactive protein (CRP), hs-CRP, IL-1, IL-6, and tumor necrosis factor (TNF) across diverse health challenges.[18,19,20] Studies have shown that curcumin can suppress the expression of proinflammatory cytokines such as IL-4 and IL-5 in conjunctival tissue in mice induced with ovalbumin.[4,21] Moreover, in vitro research has demonstrated that curcumin can mitigate the upregulation of IL-1β induced by hyperosmotic conditions in corneal epithelial cells, involving the p38 mitogen-activated protein kinase (MAPK/NF-κB) pathways.[22] Thus, curcumin may be a potentially effective therapeutic agent for alleviating inflammation associated with DED.

A study by Borselli et al.[16] randomized 48 cases of DED into two groups – oral curcumin group and tear substitute group in addition to topical sodium hyaluronate 0.25%. The study was conducted in European eyes. An oral formulation of 100 mg curcumin with 200 mg soy-phospholipid was used. At 90 days follow-up, there was greater improvement in OSDI score and ocular and bulbar redness in the curcumin group. Contrarily, this study was a double-blinded study comparing placebo with bio-enhanced curcumin on Indian eyes with non-severe DED. The dose and formulation in our study were different (bio-enhanced curcumin 500 mg BD). The objective parameters (TMH, staining score, LLT, TBUT, non-invasive TBUT, bulbar redness) in addition in the OSDI score were significantly better than the placebo group. This study highlights the efficacy of bio-enhanced curcumin in Indian eyes with non-severe DED.

Other studies broadly discuss the therapeutic role of curcumin in various eye diseases in addition to other oral supplements.[4,5,6,11]

Curcumin is an active ingredient of turmeric which constitutes an important part of spices that are used in Indian households. The amount of curcumin available through diet may range from 60–100 mg curcumin. However, since the bioavailability may vary depending of metabolism, this may have played a similar role in both the groups of the study. The study lacks to estimate the role of dietary curcumin in addition to supplements. This is one of the limitations of the study. The formulation and dosage (1000 mg bio-enhanced curcumin daily) used in the study improves the bioavailability to 6.93-folds as compared to normal curcumin and about 6.3-folds compared to the curcumin-lecithin-piperine formula.[23] However, the absence of assessment of tear inflammatory markers and evaluation of serum curcumin levels is one of the limitations of the study. There are studies exploring the role of topical curcumin too; however, they are in the early stages.[24,25]

The study has various strengths. The randomized, double-masked, placebo-controlled study provides higher evidence of the effectiveness of oral bio-enhanced curcumin in treating DED. The OSDI score correlates with the results of various objective tests. However, the study has a few limitations as well. The dosage of bio-enhanced curcumin was prescribed as advised by the manufacturer. A smaller dosage may result in similar benefits. Few objective parameters improved at 1 to 2 months in the study and remained stable at 3 months. Another limitation of the study is that the OSDI score was taken as the primary outcome parameter despite being a subjective test. Other objective tests like NIBUT were considered as secondary outcome parameters. Only one eye readings were taken for analysis, generalized models taking account of the parameters of both eyes would have enhanced the reliability of the study. The sample size of the study was small, and a study with improved methodology and a larger sample size may provide more comprehensive results. A shorter duration of consumption of oral curcumin may probably result in similar benefits. The study limits its inclusion to mild to moderate (non-severe) DED. Thus, the minimum required drug dosage, duration of prescription, and effect of oral curcumin in cases of severe DED still remain unexplored.

Conclusion

Oral bio-enhanced curcumin is a safe and effective adjunctive treatment for mild to moderate DED. It significantly improves tear film stability, tear meniscus height, tear volume, lipid layer thickness, and reduces bulbar redness. While no significant changes were observed in limbal redness, corneal staining, or Schirmer’s test, its overall benefits suggest potential as a supportive therapy for DED management. Mild adverse reactions were minimal, indicating good tolerability. Further studies with larger sample sizes and longer follow-ups are warranted to validate these findings and explore its long-term efficacy.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.