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Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.

These are tiny cystic vesicles present on the outer (epithelial) surface of the cornea. They can arise in a number of different conditions:

  • Associated with certain types of contact lens.[1]
  • Associated with recurrent corneal erosion syndrome.[2]
  • In the presence of vapours of certain industrial chemicals, eg aliphatic, alicyclic and heterocyclic amines.
  • Associated with certain corneal dystrophies (epithelial basement membrane dystrophy (EBMD) or Cogan's microcystic corneal dystrophy and Meesmann's dystrophy).[3]
  • They have been more recently associated with interferon therapy and exemestane.
  • There are reports of corneal microcysts developing after belantamab-mafodotin treatment for relapsed or refractory multiple myeloma.[4]
  • They may be found in pre-invasive carcinoma of the cornea.

This varies with the aetiology, the most common being microcysts associated with contact lens wear.

Some may be asymptomatic. Others may cause ocular irritation or transient blurred vision and - if they rupture - cause painful corneal erosions which show up as punctate epithelial erosions (there will be scattered pinpoints of fluorescein uptake across the corneal surface).

This depends on the underlying cause but, generally, these patients are managed in an ophthalmology clinic. The source is removed where possible (such as in the case of contact lenses) and intensive lubrication with the aim to limit cyst formation and rupture is the mainstay of treatment.

If they persist and repeatedly rupture, they may be treated as would a case of recurrent corneal erosion syndrome, ie topical chloramphenicol, lubricants and - if there is no improvement - a period wearing a bandage contact lens (a soft lens with no refractive power that sits over the cornea and protects it from the shearing forces of the blinking lids). In severe cases, focal debridement may be required.

If they fail to heal adequately, the patient may go on to develop the self-perpetuating condition of recurrent corneal erosion syndrome, whereby there is an ongoing cycle of cyst formation and rupture as the epithelium does not have the time to heal fully.

This depends on the cause. Microcysts associated with wearing contact lenses should settle when the lenses are removed. Microcysts associated with corneal erosion syndrome, as are found in dry eye, should settle with intensive (and ongoing prophylactic) lubrication. Cysts arising as a result of industrial chemical vapour exposure settle over a few hours after vacation of the vapour, with no long-term sequelae. Corneal dystrophies are generally progressive disorders which worsen over time.

Good patient education with regards to wearing contact lenses, and lubrication.

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Further reading and references

  1. Gurnani B, Kaur K; Contact Lens-Related Problems and Complications.

  2. Napoli PE, Braghiroli M, Iovino C, et al; A study of refractory cases of persistent epithelial defects associated with dry eye syndrome and recurrent corneal erosions successfully treated with cyclosporine A 0.05% eye drops. Drug Des Devel Ther. 2019 Jun 1913:2001-2008. doi: 10.2147/DDDT.S207453. eCollection 2019.

  3. Moshirfar M, Bennett P, Ronquillo Y; Corneal Dystrophy.

  4. Mencucci R, Cennamo M, Alonzo L, et al; Corneal Findings Associated to Belantamab-Mafodotin (Belamaf) Use in a Series of Patients Examined Longitudinally by Means of Advanced Corneal Imaging. J Clin Med. 2022 May 1911(10):2884. doi: 10.3390/jcm11102884.