Table 1 Summary of the reported nanomaterial-laden contact lenses for diagnosis and treatment of glaucoma

Latanoprost-eluting contact lens (CLs)

Treatment

Long-term release of latanoprost, safe in cell and animal studies

Rapid initial release of the drug followed by prolonged drug release over four weeks

[54]

Pueranin-cyclodextrin nanoparticles (NPs)-laden CL

Treatment

Significant drug loading capacity, long drug retention time

Increased retention time of pueranin-cyclodextrin NPs-laden CLs compared to 1% puerarin eye drop (77.45 min vs.12.88 min)

[55]

Timolol maleate (TM)- implant CL

Treatment

Controlled drug delivery, safe in eye irritation and cytotoxicity analysis, enhanced mean residence time compared with eye drop

Prolonged drug release for 168 h, sustained IOP reduction for 192 h in rabbit

[56].

Vitamin E-loaded pHEMA-hydrogel CLs

Treatment

Increased drug loading

Increasing the timolol and brimonidine loading on the lenses by 19.1% and 18.7%, respectively, without significant change in the duration of drug release from the lenses

[57]

latanoprost-loaded PLGA NPs-laden CLs

Treatment

Sustained delivery of latanoprost

Significantly greater IOP reduction compared to the eye drops on day 3, 5, and 8 for the high-dose CLs

[58]

Acetazolamide-loaded polymeric CLs

Treatment

Sustained drug release

Long term drug release from the nano-drug complex for 3 h with the complete destruction of the polymer matrix within 5 min

[59]

Brimonidine @LDH/Thermogel-laden CLs

Treatment

High biocompatibility, non-toxic for human corneal epithelium

In vitro sustained release for up to 144 h, in vivo sustained release for at least 7 days

[60]

Nanogel-laden bicontinuous microemulsion timolol-eluting CLs

Treatment

Good oxygen permeability and optical transmission, controlled release of drugs only when the CLs is worn

Drug release at 35 C while maintaining oxygen permeability and optical transmission

[62]

Bimatoprost/latanoprost -eluting vitamin-E modified CLs

Treatment

Good biocompatibility, extended release of drug

Extended release of bimatoprost by 10 to 40-fold. Sustained delivery of therapeutic doses for more than 10 days

[63]

Timolol maleate-loaded chitosan-alginate NPs-laden CLs

Treatment

Sustained drug delivery and improved patient compatibility

Sustained drug release for 3 days, extending up to 6 days

[64]

Bimatoprost-loaded microemulsion-laden CLs

Treatment

Low burst release, improvement in the retention time of drug

The two-fold increase in the uptake/loading of bimatoprost, improved in vitro release rate profiles up to 48 to 96 h

[66]

Timolol/latanoprost-loaded micelles-laden CLs

Treatment

Sustained release of timolol and latanoprost,

improved bioavailability and residence time

Long-term release of timolol and latanoprost, respectively, for up to 120 and 96 h in tear fluid, improved mean bioavailability (2.2-fold and 7.3-fold) and residence time (79.6-fold and 122.2-fold) compared to eye drops for both timolol and latanoprost, respectively

[31]

Timolol-loaded microemulsion-laden soft CLs

Treatment

High drug loadings, controlled release of drug in deionized water

Slow drug release in deionized water for gels containing timolol-loaded microemulsions, very rapid release in PBS and in saline due to greater solubility of timolol in these solutions compared to deionized water

[68]

Travoprost-loaded microemulsion soaked CLs

Treatment

Improved drug loading, swelling and optical transmission properties

Enhanced drug loading/uptake and improved physical properties of travoprost loaded microemulsion soaked CLs compared with the traditional soaking method, slow (48–120 h) in vitro drug release, high drug retention time in the tear fluid

[69]

Timolol-loaded microemulsion-laden silicone CL

Treatment

Improved drug loading/release, and retention

2-fold improvement in timolol loading, improved drug release up to 48–96 h, improved retention time in rabbit tear fluid, prolonged IOP reduction up to 96 h

[70]

Latanoprost-loaded PEGylated solid lipid NPs- laden soft CL

Treatment

Improved swelling, safe in histopathological studies, improved drug loading and sustained drug release

High drug uptake and sustained drug release up to 96 h for LP-pSLN-L lenses, high drug concentration at all-time points up to 96 h in animal studies

[71]

Timolol maleate (TM)-loaded nanodiamond (ND)-embedded CL

Treatment

Sustained release of drug, retention of drug activity in primary human trabecular meshwork cells

Controlled and sustained release of timolol maleate in the presence of lysozyme

[76]

Timolol-loaded gold NPs (GNPs)-laden CL

Treatment

Significant loading/ uptake of drug with the GNPs without altering their physical characteristics

Significant decrease IOP (72 h), high concentration of timolol with CLs loaded with GNPs compared with the soaked CLs without GNPs, no significant enhancement in the rate of timolol release

[77]

Levobunolol-loaded eudragit NPs-laden CL

Treatment

Improved swelling properties, transmittance, sustained drug release, and enhanced drug permeation

Sustained drug release, enhanced permeation through the CLs compared to commercially available eye drops

[80]

Bimatoprost-loaded graphene oxide-laden CLs

Treatment

Improved swelling properties and transmittance of CL, controlled release of drug

Not improved bimatoprost uptake, enhanced in vitro drug release, substantial decrease in the cumulative and burst release of bimatoprost, substantial improvement in the mean residence time compared to the eye drop solution

[81]

Timolol-eluting graphene oxide-laden silicone CL

Treatment

Improved swelling properties, controlled drug release, sustained drug delivery

Significant reduction in burst release and improved release profiles compared to the respective CLs without GO, significant enhancement in mean residence time

[82]

Timolol maleate-loaded silica poly methacrylic acid (PMAA) NPs incorporated CL

Treatment

Great biocompatibility and high physical/ chemical stability, pH-responsive drug release, sustained drug release at physiological pH

No substantial release of pH-responsive timolol maleate by silica-alginate composite NPs, promising release of pH-responsive timolol maleate by silica-PMAA NPs

[83]

Brimonidine-loaded silica NPs-laden silicone CLs

Treatment

Improved oxygen permeability, transmittance, swelling, and reduced lysozyme adherence, controlled drug delivery, enhanced safety for human applications, increased convenience, and heightened adherence by patients

Controlled release of brimonidine for up to 144 h, high concentration of brimonidine for 96 h in a rabbit tear fluid model, low cumulative drug release

[84]

Drug-eluting mesoporous silica NPs-laden CLs

Treatment

Prolonged drug release, improved drug loading capacity and compatibility, safe for ocular use

Sustained release of glaucoma drugs, controlled drug release over time, good drug loading

[85]

Graphene and carbon nanotubes-laden CL

Diagnosis

Ease of fabrication, good repeatability, linearity, and accuracy in tracking fluctuating IOP levels

High sensitivity (36.01 µV mmHg − 1), capability to track dynamic pressure changes within the normal IOP range of 9 to 34 mmHg

[91]

Graphene nanowalls (GNWs)-laden CL

Diagnosis

Non-invasive technique, continuous IOP monitoring with high sensitivity and minimal power consumption

IOP monitoring with the sensitivity of 42,250 (ppm/mmHg), surpassing that of the IOP tonometer

[92]

Soft and transparent nano -based CL

Diagnosis

Real-time IOP monitoring in human eyes, excellent biocompatibility, achieving accuracy comparable to the gold-standard tonometry, stable against inflammation, thermal exposure, and electromagnetic radiation, causing minimal corneal abrasion, safe in ten human participants

Accurate quantitative measurements of IOP without inducing inflammation, providing the measurements in rabbits that match those of a commercial tonometer

[93]

Transparent silver nanowire-laden smart CLs

Diagnosis

Noninvasive and continuous IOP monitoring

Successful monitoring of IOP changes in living rabbit eyes

[95]

Gold hollow nanowire-based CLs

Diagnosis

High ocular strain sensitivity, chemical stability and biocompatibility

Successful IOP monitoring in glaucoma induced rabbits, ability for on-demand delivery of timolol to regulate IOP

[96]

Gold nanobowls (AuNBs)-based CL

Diagnosis

Convenient, noninvasive, and possibly multifunctional platform for monitoring diagnostic biomarkers in human tears

Dual-functional smart CLs sensor for IOP monitoring, quantitative analysis of MMP‐9 at a low nanomolar range in real tear samples

[97]