Home About us Editorial board Ahead of print Current issue Search Archives Submit article Instructions Subscribe Contacts Login 
  • Users Online: 6013
  • Home
  • Print this page
  • Email this page

   Table of Contents      
CASE REPORT
Year : 2020  |  Volume : 68  |  Issue : 1  |  Page : 224-226

Severe focal stromal degeneration up to Descemet membrane after corneal collagen cross-linking


Department of Cornea and Refractive Surgery, Sankara Eye Hospital, Coimbatore, Tamil Nadu, India

Date of Submission14-Mar-2019
Date of Acceptance24-Sep-2019
Date of Web Publication19-Dec-2019

Correspondence Address:
Dr. G V Prabhakar
Department of Cornea and Refractive Surgery Sankara Eye Hospital, Sathy Road, Coimbatore - 641 035, Tamil Nadu
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijo.IJO_475_19

Rights and Permissions
  Abstract 


Corneal collagen cross-linking (CXL) is an effective treatment for arresting progression in keratoconus cases. It is considered safe despite a few complications that have been recorded earlier. In this case series, we report a rare and late complication caused due to severe stromal thinning up to Descemet's membrane in three patients who underwent CXL 3 to 6 years back for keratoconus. Deep anterior lamellar keratoplasty (DALK) was then done for the affected eye with good outcomes. This case series highlights the possible late effects of UVA irradiation post CXL.

Keywords: Collagen cross-linking, descemetocele, keratoconus, stromal thinning, ultraviolet A irradiation


How to cite this article:
Prabhakar G V, Panickar N, Reddy J K, Sivasubramaniam S K, Singh A. Severe focal stromal degeneration up to Descemet membrane after corneal collagen cross-linking. Indian J Ophthalmol 2020;68:224-6

How to cite this URL:
Prabhakar G V, Panickar N, Reddy J K, Sivasubramaniam S K, Singh A. Severe focal stromal degeneration up to Descemet membrane after corneal collagen cross-linking. Indian J Ophthalmol [serial online] 2020 [cited 2020 Apr 10];68:224-6. Available from: http://www.ijo.in/text.asp?2020/68/1/224/273247



Corneal collagen cross-linking (CXL), first introduced by Wollensack et al.,[1] is currently considered as a standard treatment for arresting progression in keratoconus patients. It strengthens the corneal collagen by forming chemical bonds, both within and between the collagen fibrils, thus enhancing the biomechanical and biochemical stability of the corneal collagen.[2] CXL involves photoactivation of riboflavin by exposure to ultraviolet A (UVA) which then increases the collagen cross-linking.

CXL has proved to be an effective treatment for most cases. However, besides the transient reversible side effects, some cases with complications such as corneal haze and scarring, reduced uncorrected and best spectacle-corrected visual acuity (BSCVA), infectious and noninfectious stromal melting, and treatment failure with the progression of ectasia have been reported.[3] In this case series, we highlight a rather rare complication of CXL noted in three patients who came to our centre 3 to 6 years post CXL (done under Dresden protocol),[1] with clinical findings of severe corneal thinning in the treated eye.


  Case Reports Top


Case 1

A 17-year-old female, presented with defective vision in the left eye (OS) for 4 months. There was no history of associated pain or photophobia. The patient was a known case of keratoconus with a history of CXL done under Dresden protocol in the left eye 4 years back.

Preoperative pachymetry values are RE- 456 microns, LE- 420 microns as per old records. On evaluation, the best-corrected visual acuity (BCVA) in the right eye was 20/80 and left eye was 20/200. On slit-lamp biomicroscopy, OS central corneal haze with a localized area of stromal thinning up to Descemet's membrane measuring 3 × 3 mm was noted [Figure 1]. Fluorescein dye showed pooling over the thinned area of cornea. There were no signs of anterior chamber inflammation. Keratometry (OS) showed mean K1 = 48.23D and K2 = 49.73D. Lens was clear and posterior segment was within normal limits. The specular count was 3214 cells/mm 2. In view of the severe stromal thinning, deep anterior lamellar keratoplasty (DALK) was done for the same eye [Figure 2]. On evaluation, the right eye was within normal limits.
Figure 1: Slit-lamp biomicroscopy image (OS) of case 1 showing central corneal haze with a localized area of stromal thinning stroma with bare Descemet's membrane

Click here to view
Figure 2: Slit-lamp biomicroscopy image (OS) of case 1 post DALK

Click here to view


Case 2

A 22-year-old male approached with complaint of defective vision in the right eye (OD) for 6 months, with past history of CXL done in the right eye 3 years back for keratoconus. The patient had no history of associated pain or photophobia. BCVA in the right eye was recorded as 20/63. Preoperative pachymetry was RE -412 microns, LE – 515 microns. On slit-lamp examination, corneal thinning up to Descemet's membrane was seen in central cornea (area 3 × 3 mm) with surrounding stromal haze, [Figure 3] with corresponding optical coherence tomography (OCT) findings [Figure 4]. The pooling of fluorescein dye was seen over the descemetocele. Anterior chamber showed no signs of inflammation. Posterior segment was within normal limits. Mean K1 = 38.4D and K2 = 50.1 D were recorded. The specular count was 3110 cells/mm 2. DALK was advised for the same eye.
Figure 3: Slit-lamp biomicroscopy image (OD) of case 2 showing severe stromal thinning in central cornea with surrounding stromal haze

Click here to view
Figure 4: OCT image (OD) of case 2 showing focal stromal thinning

Click here to view


Case 3

A 21-year-old male came to our hospital with defective vision (OD) for 4 months. The patient gave a history of CXL in the right eye 6 years back. Preoperative pachymetry was RE- 410 microns, LE- 510. He had a known case of keratoconus. On presentation, recorded BCVA was 20/200. Slit-lamp examination showed severe stromal thinning up to Descemet's membrane measuring 2 × 3 mm in the affected eye involving the central corneal area [Figure 5]. Fluorescein stain pooling was seen over the bare Descemet's membrane. Specular was 3200 cells/mm 2. Posterior segment was within normal limits. Mean K1 = 42.03D and K2 = 45.73D were recorded. In view of the severe stromal thinning, deep anterior lamellar keratoplasty (DALK) was done for the same eye. The left eye was within normal limits.
Figure 5: Slit-lamp biomicroscopy image (OD) showing severe stromal thinning with bare Descemet's membrane in central cornea

Click here to view



  Discussion Top


CXL is considered a gold standard treatment for progressive keratoconus. Our case series reports a rare complication and a long-term follow up highlighting deleterious effects of UV radiation. The continued effect of CXL resulting in stromal degeneration up to Descemet's membrane between 3 to 6 years post CXL can be attributed to the following hypotheses reported in literature.

Zare et al.,[4] conducted a study which showed that anterior and mid-stromal keratocyte density decreases greatly after CXL. Keratocyte repopulation occurs but does not complete after 6 months of the procedure. If considerable regeneration of stromal keratocytes fails to occur, it could result in stromal thinning.

The same study also demonstrated that besides the neurotrophic deficit resulting from keratoconus, CXL treatment in itself contributes to the problem by UV rays causing deeper nerve damage. Their results indicated that nerve regeneration occurs gradually, however even after 6 months post CXL the nerve plexus was not well defined. The cases in our study also reported painless diminution of vision owing to the corneal thinning that resulted during post CXL treatment.

Lim LS et al.,[5] in their study showed that, UVA exposure which causes keratocyte death may show a sublethal effect in the deeper stroma which receives lower dose of radiation, resulting in fibroblastic transformation of the keratocytes with subsequent scar formation which may further decrease the supply of nutrition from aqueous to the superficial stroma.


  Conclusion Top


This is a first-ever case series reporting a rare complication of stromal thinning up to Descemet's membrane 3 to 6 years post CXL. This case series highlights the fact that effect of CXL continues in a long course of time and a better understanding of long-term effects of UVA irradiation is needed. Intraoperative parameters during CXL treatment such as exposure time and UVA dose play an important role in the outcomes.

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

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-A–induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003;135:620-7.  Back to cited text no. 1
    
2.
Spoerl E, Huhle M, Seiler T. Induction of cross-links in corneal tissue. Exp Eye Res 1998;66:97-103.  Back to cited text no. 2
    
3.
O'Brart DP. Corneal collagen cross-linking: A review. J Optom 2014;7:113-24.  Back to cited text no. 3
    
4.
Zare MA, Mazloumi M, Farajipour H, Hoseini B, Fallah MR, Mahrjerdi HZ, et al. Effects of corneal collagen crosslinking on confocal microscopic findings and tear indices in patients with progressive keratoconus. Int J Prev Med 2016;7:132.  Back to cited text no. 4
  [Full text]  
5.
Lim LS, Beuerman R, Lim L, Tan DT. Late-onset deep stromal scarring after riboflavin–uv-a corneal collagen cross-linking for mild keratoconus. Arch Ophthalmol 2011;129:360-71.  Back to cited text no. 5
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]



 

Top
 
 
  Search
 
    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
Abstract
Case Reports
Discussion
Conclusion
References
Article Figures

 Article Access Statistics
    Viewed237    
    Printed1    
    Emailed0    
    PDF Downloaded64    
    Comments [Add]    

Recommend this journal