Aetiology

Corneal hydrops is a rare complication of primary corneal ectasias such as keratoconus in which aqueous humour enters the cornea, leading to corneal oedema. It is conventionally believed to be due to rupture of Descemet’s membrane, although hydrops can occur with an intact Descemet’s membrane.
The estimated UK annual incidence of acute corneal hydrops in keratoconus is 1.4 per 1000
Most cases occur in the second or third decade of life, with men affected 2-3 times more than women

Predisposing factors

Keratoconus, keratoglobus, pellucid marginal degeneration or other primary corneal ectasia; high risk in advanced keratoconus

Vernal keratoconjunctivitis

Asthma

Eye rubbing may be a risk factor

Symptoms of corneal hydrops

Sudden reduction in visual acuity
Pain
Photophobia
Watering
Contact lens intolerance

Signs of corneal hydrops

Gross stromal oedema with or without epithelial oedema

• usually over a clearly demarcated area (typically inferior to the cone)
  • Descemet’s membrane rupture may be visible
• peripheral cornea usually spared, except in pellucid marginal degeneration

Differential diagnosis

Other causes of corneal oedema including Fuchs dystrophy and infective keratitis

Management by optometrist

Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere

Acute hydrops

• cease contact lens wear
• avoid bandage contact lens (hypoxia may induce corneal vascularisation)
• initially, review weekly for appearance of vascularisation or other complication
  • majority of cases resolve over 2-4 months, often with a degree of stromal scarring
  • if corneal vascularisation appears, refer urgently to ophthalmologist

After resolution

• reassess corneal topography (often less steep after hydrops)
• will probably still need contact lens for optimum acuity; lens fit will need to be reviewed as corneal profile may have changed

(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Topical lubricants for symptomatic relief
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Cycloplegia for symptomatic relief, e.g. gutt. cyclopentolate 1% twice daily for at least a week
(GRADE*: Level of evidence=low, Strength of recommendation=weak)

Systemic analgesia if necessary (e.g. ibuprofen, or paracetamol if contraindicated) 
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Consider prophylactic topical antibiotic (e.g. gutt. chloramphenicol 0.5%) if epithelial surface acutely disturbed by oedema and if secondary infection seems likely to occur
(GRADE*: Level of evidence=low, Strength of recommendation=weak)
 

Referral category

B2: alleviation/palliation: normally no referral
A3: first aid measures and urgent referral (if vascularisation present)

Possible management by ophthalmologist

Treat pain, prophylactic antibiotic if indicated, topical steroid if corneal vessels proliferate, penetrating keratoplasty if scarring reduces acuity following resolution.
Possible intracameral gas injection with or without compression sutures to bring the oedematous and biomechanically weak cornea in closer proximity to the endothelium.

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)

Sources of evidence

Barsam A, Brennan N, Petrushkin H, Xing W, Quartilho A, Bunce C, Foot B, Cartwright NK, Haridas A, Agrawal P, Suleman H, Ahmad S, MacDonald E, Johnston J, Tuft S. Case-control study of risk factors for acute corneal hydrops in keratoconus. Br J Ophthalmol. 2017;101(4):499-502

Barsam A, Petrushkin H, Brennan N, Bunce C, Xing W, Foot B, Tuft S. Acute corneal hydrops in keratoconus: a national prospective study of incidence and management. Eye (Lond). 2015;29(4):469-74

Chaurasia S, Ramappa M, Murthy S.Rapid. Resolution of Large and Non- Resolving Corneal Hydrops using a modified technique of compression sutures. Semin Ophthalmol. 2022;37(5):637-642. 

Fan Gaskin JC, Patel DV, McGhee CN. Acute corneal hydrops in keratoconus – new perspectives. Am J Ophthalmol. 2014;157(50):921-8

Musayeva A, Santander-García D, Quilendrino R, Parker J, van Dijk K, Henrat C, Dapena I, Binder PS, Melles GRJ. Acute hydrops after Bowman layer transplantation for keratoconus may indicate that Descemet membrane rupture Is secondary to hydrops. Cornea. 2022;41(12):1512-1518

Panda A, Aggarwal A, Madhavi P, Wagh VB, Dada T, Kumar A, Mohan S. Management of acute corneal hydrops secondary to keratoconus with intracameral injection of sulfur hexafluoride (SF6). Cornea 2007;26(9):1067- 9

Rowson NJ, Dart JK, Buckley RJ. Corneal neovascularisation in acute hydrops. Eye (Lond). 1992;6:404-6

Sharma N, Maharana PK, Jhanji V, Vajpayee RB. Management of acute corneal hydrops in ectatic corneal disorders. Curr Opin Ophthalmol. 2012;23(4):317-23

Corneal hydrops
Version 14
Date of search 08.06.23
Date of revision 08.08.23
Date of publication 17.10.23
Date for review 07.06.25
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