## 1 Introduction
### Magnetic Nanotechnology  
The field of nanotechnology has demonstrated significant potential for enhanced and targeted drug delivery to the cornea [35]. Nanoparticles, ranging in size from 1 to 100 nm, exhibit unique interactions with cells and tissues at the molecular level, offering advantages such as sustained drug release and precise targeting capabilities [36]. Magnetic nanoparticles (MNPs) possess the distinct ability to align their magnetic spins with an external magnetic field, thereby achieving magnetisation. Originally recognised for their application in magnetic resonance imaging (MRI) for diagnostic purposes, MNPs have experienced substantial growth in biomedical applications over the past few decades [37]. This versatile class of nanoparticles includes metallic, bimetallic, and superparamagnetic iron oxide nanoparticles (SPIONs) [38]. MNPs serve as effective drug delivery systems due to their reactive surfaces, which allow for functionalisation with biocompatible coatings, bioactive molecules, or targeting moieties, thereby enhancing specificity for cellular targets while reducing interactions with healthy tissues [39; 40]. Furthermore, MNPs can be manipulated using non-contact forces, thereby extending their potential beyond simple molecular transport [41]. When comparing nanoparticles to microparticles (typically around 4 \(\upmu\)m), [PERSON] et al. showed that nanoparticles demonstrated significantly lower toxicity, as evidenced by higher corneal endothelial cell (CEC) counts and reduced iron deposition compared to microparticles [42]. Additionally, nanoparticles generated fewer reactive oxygen species (ROS), which minimises oxidative stress and potential cellular damage. These properties contribute to their lower toxicity profile and improved biocompatibility, making nanoparticles particularly promising for ophthalmic applications [42]. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline
**Comeal Endothelial Disease** & **Current Treatments** \\ \hline Fuchs’ Endothelial Corneal Dystrophy & Conservative Management: Hypertonic saline drops Surgical Options: Endothelial keratoplasty (EK), Descemet’s stripping endothelial keratoplasty (DSEK), Descemet’s membrane endothelial keratoplasty (DMEK) \\ \hline Bullous Keratopathy & Conservative Management: Hypertonic saline drops, bandage contact lenses Surgical Options: EK, DSEK, DMEK \\ \hline Endothelial Decompensation due to Contact Lens Wear or Infections & Antimicrobial Therapy: Treatment of underlying infections Surgical Options: EK, DSEK, DMEK \\ \hline Congenital Hereditary Endothelial & Medical Management: Symptomatic relief with lubricating drops Surgical Options: EK, DSEK, DMEK \\ \hline Posterior Polymorphous Corneal Dystrophy (PPCD) & Conservative Management: Monitoring for progression Medical Management: Hypertonic saline drops Surgical Options: Glaucoma Drainage Implants, EK, DSEK, DMEK \\ \hline Iridocorneal Endothelial Syndrome (ICE) & Medical Management: Hypertonic saline drops, Topical medications to control intraocular pressure Surgical Options: Trabeculectomy, Glaucoma Drainage Implants, EK, DSEK, DMEK \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Overview of current treatments for corneal endothelial diseases. This table summarises the various treatments available for common corneal endothelial diseases, highlighting both conservative and surgical options. While MNPs are proposed for therapeutic injection of CECs, they have also demonstrated the ability to target the posterior segment of the eye. In a study by [PERSON] et al., MNPs were functionalised with vascular endothelial growth factor (VEGF), a bioactive molecule known for its transcytosis capability from the retinal pigment epithelium (RPE) to deeper ocular layers, effectively directing the MNPs to the choroid [43]. These results highlight the potential of MNPs combined with various bioactive molecules to enhance targeted cell delivery within the eye.