Summary

Keratopathy is defined as disease of the cornea. There are many different types of keratopathy; some have local causes, whereas others have systemic causes. Here, we provide a summary of some of the important types of keratopathy to learn about for the Duke-Elder exam.

Neurotrophic keratopathy

Neurotrophic keratopathy (NK) is caused by loss of trigeminal innervation to the cornea, resulting in anaesthesia (partial or complete) and ulceration of the cornea. Loss of innervation results in intracellular oedema, exfoliation, loss of goblet cells and breakdown of the epithelium, causing persistent ulceration.

Causes:

NK may be caused by any condition that damages the trigeminal nerve.

• Stroke
• Tumour
• Surgical ablation of the trigeminal ganglia (for trigeminal neuralgia)
• Peripheral neuropathy (e.g. due to diabetes)
• Infection - herpes simplex and herpes zoster keratitis

Clinical features:

• Loss of sensation to the cornea (painless)
• Persistent epithelial defect (i.e. ulceration) which can lead to stromal oedema and stromal “melting” (where the cornea becomes very soft due to enzymatic degradation and breakdown of corneal collagen)

Management:

• Discontinue any potentially toxic drugs
• Topical lubricants - for associated dry eye/corneal exposure
• Topical/systemic anticollagenase agents e.g. tetracyclines
• Cenegermin - a topical recombinant human nerve growth factor, has been reported to be of benefit in moderate/severe ulcers (but the long-term effects are not yet known)