• Users Online: 289
  • Print this page
  • Email this page

 Table of Contents  
Year : 2023  |  Volume : 3  |  Issue : 1  |  Page : 35-37

Coincidental occurrence of severe hydrops after corneal collagen cross-linking

1 Cornea and Anterior Segment Services, L J Eye Institute, Ambala, Haryana, India
2 Cornea and Anterior Segment Services, Sankara Nethralaya, Chennai, Tamil Nadu, India
3 Department of Ophthalmology, AIIMS, Nagpur, Maharashtra, India

Date of Submission27-May-2022
Date of Acceptance26-Aug-2022
Date of Web Publication20-Jan-2023

Correspondence Address:
Vikas Mittal
Cornea and Anterior Segment Services, L J Eye Institute, 251, Model Town, Ambala City - 134 002, Haryana
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1325_22

Rights and Permissions

This case report describes a case of acute corneal hydrops (ACH) within 4 days following collagen cross-linking that was done to arrest the progression of keratoconus in a 15-year-old girl. She developed pain, redness, and watering in the left eye within 4 days of undergoing an uneventful bilateral corneal collagen cross-linking. The diagnosis of ACH was made and was managed medically with a course of topical steroids. A large fluid-filled stromal pocket with iris adhering to the posterior surface was observed that resolved with stromal scarring after the treatment. Thus, ACH may be precipitated by cross-linking and needs to be managed appropriately.

Keywords: Acute corneal hydrops, anterior segment optical coherence tomography, corneal collagen cross-linking, keratoconus

How to cite this article:
Mittal V, Jain N, Agarwal M, Narang P. Coincidental occurrence of severe hydrops after corneal collagen cross-linking. Indian J Ophthalmol Case Rep 2023;3:35-7

How to cite this URL:
Mittal V, Jain N, Agarwal M, Narang P. Coincidental occurrence of severe hydrops after corneal collagen cross-linking. Indian J Ophthalmol Case Rep [serial online] 2023 [cited 2023 Feb 1];3:35-7. Available from: https://www.ijoreports.in/text.asp?2023/3/1/35/368132

Acute corneal hydrops (ACH) is one of the complications seen in patients with progressive keratoconus. It has been known that many factors such as increased epithelial thickening, stromal thinning at the keratoconus cone, anterior hyper reflectivity at the Bowman's layer level, and the absence of stromal scarring are associated with a high risk of developing ACH.[1] Corneal collagen cross-linking (CXL) has been shown to prevent the progression of keratoconus.[2] However, hydrops has been reported after 3 years in a young patient who underwent CXL and intra-corneal ring segment with an intervening episode of exacerbation of allergic conjunctivitis. They postulated young age, eye rubbing, and allergic conjunctivitis as the causative factor for ACH in this patient.[3] Hereby, we present an unusual case of keratoconus where a patient underwent bilateral CXL and one eye developed ACH 4 days after the procedure.

  Case Report Top

A 15-year-old girl underwent an uneventful standard epithelium-off CXL using Dresden protocol in both the eyes (with isotonic riboflavin over central 8-mm cornea) at another facility.[4] On her preoperative topography, maximum keratometry of 51.3 D, minimum keratometry 46.2 D, and thinnest pachymetry 414 μ were seen in the right eye (OD). Whereas in the left eye (OS), maximum keratometry 58.0 D, minimum keratometry 50.5 D, and thinnest pachymetry 390 μ were seen. She was diagnosed with keratoconus in both eyes[Figure 1]a and [Figure 1]b. Vision before she underwent CXL was not available as the procedure was done at another facility.
Figure 1: (a) The left eye image depicting localized corneal edema in the central 4-mm cornea with iris plugging the posterior corneal endothelium after corneal collagen cross-linking (b) Anterior segment optical coherence tomography (AS-OCT) of the left eye showing increased central corneal thickness. An encapsulated hypoluscent lesion can be seen suggestive of large stromal fluid pocket. Iris plugging can be seen posteriorly (c) 18 months follow-up showing central corneal scarring with adherent iris strands (d) AS-OCT of left eye showing corneal scar and iris tissue adhering to posterior stroma

Click here to view

Four days after the procedure, she developed sudden onset of pain, redness, swelling, diminution of vision, and whitish opacity in OS. She was started on lubricants and topical anti-glaucoma medications and 10 days later, was referred to a cornea specialist for further management because of the non-resolving corneal edema. Her clinical records showed that the best-corrected visual acuity (BCVA) in OD was 20/40 and in OSwas hand movements. There was no past history of eye rubbing, vernal keratoconjunctivitis, or other atopic diseases. Slit-lamp examination in OD showed mild anterior stromal haze, prominent nerves, and conical cornea. In OS, dense central corneal edema with a large fluid pocket in the stroma and central iris adhering to the posterior corneal surface with a quiet anterior chamber was seen [Figure 1]c. No obvious Descemet's membrane (DM) break was visible. Intraocular pressure (IOP) by applanation tonometry in OD was 10 mmHg and digital IOP in OS was normal. Anterior segment optical coherence tomography (AS-OCT) showed a central corneal thickness of 440 μm in OD and 2230 μm in OSwith a large intra- stromal fluid pocket [Figure 1]d. The patient was started on topical hypertonic sodium chloride 5% and carboxymethylcellulose sodium 0.5%, six times a day each in OS. A bandage contact lens of 18 mm was applied. Two weeks later, visual acuity improved to 20/300 in OS. Slit-lamp examination showed a decrease in the extent of corneal edema (883 μ on AS-OCT).

Because of the logistic issues as it was difficult for the patient to follow-up at the previous centers in view of travel restrictions, she was then referred to our center. On slit-lamp examination, localized corneal edema with a adherent leucoma at 9 o'clock in the para-pupillary was seen. She was started on topical prednisolone acetate 1% (six times daily and then tapered) and homatropine 2% eye drops in OS. After 2 weeks, a decrease in corneal edema was seen associated with improved BCVA of20/80. At 2 months, her BCVA in OS was 20/50 with an early posterior subcapsular cataract. At the last follow-up, at 18 months, the BCVA in OS was 20/40 with mild central corneal scarring. The topography maps showed stable keratoconus in both eyes. As her cataract was not progressing and the patient was comfortable with the vision, cataract surgery was deferred and she was advised to follow-up six monthly.

  Discussion Top

ACH develops following a split in DM (as a consequence of exposure to distending IOP forces that are more than corneal resistance to them), which allows aqueous to enter the stroma with gross epithelial and stromal edema.[5],[6] Although CXL is presumed to be a safe and effective procedure to strengthen the ectatic cornea, few associated complications such as corneal haze, delayed epithelial healing, corneal infection, endothelial burns, anterior uveitis, raised IOP, etc., have been published.[7],[8],[9] Corneal hydrops associated with progression of keratoconus secondary to failure of CXL procedure has been reported in a 15-year-old patient that occurred 3 years post the procedure but corneal hydrops precipitated within 4 days of CXL is quite unusual.[3]

The clinical presentation of hydrops in the present case was also different and hence, we tried to analyze the possible mechanisms involved. Our patient underwent simultaneous CXL in both eyes and the eye with more severe keratoconus (thinner pachymetry and higher keratometric values) developed hydrops. According to the study by Barsam et al.,[10] a minimum keratometry of ≥ 48 D was associated with a significantly increased risk of ACH. It may be possible that an already high keratometry (Kmax > 58.00 D) in OS and the natural history of disease were responsible for hydrops in our case and CXL was just an association. However, although the worse eye had hydrops, the cornea in this eye was around 400-μm thick, and it is uncommon to see hydrops at this corneal thickness.

The edema noticed in the present case was localized to the central 5 mm of the cornea with peripheral cornea almost unaffected; the stroma had a large fluid pocket stretching it to 2.3 mm[Figure 1]d, and the iris was adherent to the endothelium. This presentation of ACH is quite unusual and difficult to explain. The possible explanation could be inadvertent localized endothelial damage in the central endothelium by UV light. The corneal edema seen in such cases is diffuse uniformly. As in the present case, localized corneal edema was seen with intra-stromal clefts as seen on AS-OCT, it goes more in favor of CH rather than endothelial toxicity secondary to UV light in CXL. The second explanation can be an influx of fluid into the ectatic central part of the cornea through a possible DM tear (although not visible) during or immediately after cross-linking caused because of the unknown reasons. This influx of fluid was perhaps sudden causing the iris to move forward and plug the tear. The peripheral cornea is thick and rigid and resisted the spread of the DM tear and the edema. The other eye that underwent CXL on the same day had good results (evidenced by stable keratoconus over one year) pointing towards less likelihood of an iatrogenic reason. We feel, this presentation of hydrops can be related mainly to CXL and the exact mechanism is yet to be understood. Also, although the ACH was not a result of simultaneous CXL but had preferred sequential CXL been done here, one would have avoided using the same protocol or technique of CXL in the other eye after one eye would have shown such deterioration.

  Conclusion Top

In conclusion, ACH may be precipitated by a procedure such as CXL that is intended to strengthen the cornea. Although the presentation of ACH after CXL could be different, the treatment and outcome remain similar to that in non-CXL eyes. Further reports may confirm the actual incidence and mechanism involved in hydrops developing after cross-linking.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Fuentes E, Sandali O, El Sanharawi M, Basli E, Hamiche T, Goemaere I, et al. Anatomic predictive factors of acute corneal hydrops in keratoconus: An optical coherence tomography study. Ophthalmology 2015;122:1653-9.  Back to cited text no. 1
Wollensak G. Crosslinking treatment of progressive keratoconus: New hope. Curr Opin Ophthalmol 2006;17:356-60.  Back to cited text no. 2
Antonios R, Dirani A, Fadlallah A, Chelala E, Hamadeh A, Jarade E. Acute corneal hydrops 3 years after intra-corneal ring segments and corneal collagen cross-linking. Middle East Afr J Ophthalmol 2016;23:156-9.  Back to cited text no. 3
[PUBMED]  [Full text]  
Wu D, Lim DK-A, Lim BXH, Wong N, Hafezi F, Manotosh R, et al. Corneal cross-linking: The evolution of treatment for corneal diseases. Front Pharmacol 2021;12:686630.  Back to cited text no. 4
Barsam A, Petrushkin H, Brennan N, Bunce C, Xing W, Foot B, et al. Acute corneal hydrops in keratoconus: A national prospective study of incidence and management. Eye (Lond) 2015;29:469-74.  Back to cited text no. 5
Fan Gaskin JC, Patel DV, McGhee CNJ. Acute corneal hydrops in keratoconus-new perspectives. Am J Ophthalmol 2014;157:921-8.  Back to cited text no. 6
Alhayek A, Lu P-R. Corneal collagen crosslinking in keratoconus and other eye disease. Int J Ophthalmol 2015;8:407-18.  Back to cited text no. 7
Cagil N, Sarac O, Cakmak HB, Can G, Can E. Mechanical epithelial removal followed by corneal collagen crosslinking in progressive keratoconus: Short-term complications. J Cataract Refract Surg 2015;41:1730-7.  Back to cited text no. 8
Kymionis GD, Karavitaki AE, Grentzelos MA, Liakopoulos DA, Tsoulnaras KI, Kontadakis GA. Topography-based keratoconus progression after corneal collagen crosslinking. Cornea 2014;33:419-21.  Back to cited text no. 9
Barsam A, Brennan N, Petrushkin H, Xing W, Quartilho A, Bunce C, et al. Case-control study of risk factors for acute corneal hydrops in keratoconus. Br J Ophthalmol 2017;101:499-502.  Back to cited text no. 10


  [Figure 1]


Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

  In this article
Case Report
Article Figures

 Article Access Statistics
    PDF Downloaded18    
    Comments [Add]    

Recommend this journal