AMNIOTIC MEMBRANE TRANSPLANT IN INFLAMMATORY CORNEAL ULCERS: INTEREST AND MODALITY OF FOLLOW-UP BY ANTERIOR SEGMENT OCT

Taieb El Baroudi, Sarah Belghmaidi, Darfaoui Zainab, Ibtissam Hajji, Abdeljalil Moutaouakil and Hassna Soummane ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 05 February 2021 Final Accepted: 10 March 2021 Published: April 2021

1. Clinical assessment and photographs at the slit lamp at D2, D8, D25 then monthly. 2. OCT of the anterior segment in the case of Amniotic membrane transplant (assessment of the thickness of the amniotic membrane and receptor cornea, degree of membrane integration with corneal stroma, epithelialization of the amniotic membrane and stability of the thickness of the corneal stroma).

Results:-
We included 87 patients, 48 men and 39 women and a sex ratio of 55.17%. The average age was 53.15 years (ranging between 32 and 92 years). The main reasons for consultation were; photophobia and eye pain.
The corneal impairment was unilateral in 57% cases and central location in 51% cases and an ulcer size that varied between 2 to 5.5mm.Etiologies were dominated by rheumatoid arthritis (22 patients), Gougerot syndrome (18 patients), ocular rosacea in 2 patients, 1 case of ocular pemphigoid, 2 cases of inflammatory psoriasis, 3 patients followed for ankylosing spondylitis, 1 case of Crhon disease revealed by an eye injury and an idiopathic ulcer in 38 patients ( Fig.1).

Anatomical result.
Complete recovery was obtained in 62% of our patients, the average recovery time was 33 days. A recurrence was reported in 11 patients. The anterior segment OCT was performed before the surgical procedure whenever it was possible. At day2, the average thickness of the inlay amniotic membrane was 226±129m. At day 8, this thickness has decreased to 109±40m. At day 25, more than 90% of patients integrated the membrane into the corneal thickness, with an average corneal thickness of 489±83m.The integration of this membrane has been associated with partial fibrosis, allowing thus the anatomical restitution of corneal thickness and corneal regeneration in 100% of patients. The epithelialization of the graft was obtained after an average of 5 weeks (Fig. 3).

Functional recovery result.
The appreciation of functional recovery consisted on measuring visual acuity under correction for all our patients.
After an average decline of 6 months, the best visual acuity under correction was more than 5/10 in 39 patients, between 1/10 and 5/10 in 28 patients and lower than 1/10 in 11 patients, 85% of patients retained central or peripheral sequellar opacity and only 1 patient displayed anatomical and functional loss of the globe (Fig. 4).

Discussion:-
Inflammatory pre-perforative ulcers and pre-perforating ulcers are rare and severe situations that involve the anatomical and functional prognosis of the eye. The etiologies are multiple and diverse resulting mainly from autoimmune rheumatic diseases. The immunological mechanisms involved in the ontogeny of these diseases are variable, involving either cellular or humorous immunity mechanisms of immediate hypersensitivity.
The clinical diaspora is rich but insufficient to make an adequate and accurate etiological diagnosis. Multidisciplinary management is therefore essential involving ophthalmologists, internists and dermatologists.
Complementary explorations are considered as corner stones in the diagnosis of these pathologies: immunological blood check-up, radiological examination, scratching of a corneal ulcer, conjunctival smear, conjunctiva biopsy with immunohistochemical study, detection of IgE in tears, electrophoresis of tears.
The treatment of these ulcers must be early and aggressive, it consisted mainly on local applications of antiinflammatory and immunosuppressive drugs (corticosteroids, ciclosporin) and/or general applications (intravenous methylprednisolone bolus, cyclophosphamide in monthly intravenous cars in cases of pathologies involving immunity humor therapy, biotherapy. Finally, orally, prednisone or various immunosuppressants such as mycophenolate mofetil can be used).
The choice of the surgical techniques to be used depend upon the size and location of the perforation and ulcer: conjunctiva resection exposing the sclera, the application of cyanoacrylic glue on the bottom of the ulcer, amniotic membrane transplantation, peripheral lamellar keratoplasty, or even transfixitic keratoplasty(3). Among these surgical techniques, amniotic membrane transplantation is a simple and effective technique for definitive or temporary reconstruction of the corneal surface, especially in countries where the availability of corneas is limited (4).The surgical use of the human amniotic membrane in pathology goes back to several decades. In context of ophthalmology, it was first used in the treatment of symblephons and conjunctivas deficits(5), IN 1995, Tseng(6) reassessed this technique in the treatment of surface eye pathologies. In 1997, Lee and Tseng (7) conducted for the first time a clinical study reporting the outcomes of amniotic membrane usage in the treatment of trophic corneal ulcers.
The amniotic membrane serves as a substrate for deficient epithelial regrowth and partially replaces the matrix of the missing stroma. The surgeon aims to integrate the amniotic membrane into the cornea; it is then used in corneal epithelial and stromal ulcers. In the case of loss of stromal substance, the best technique is to perform a multilayered amniotic transplant. This technique has been reported for the first time by Kruse (8) in the management of deep ulcers. Amniotic membrane transplantation has also demonstrated its effectiveness in repairing corneal perforations in several studies (9-10).
In the follow-up of the amniotic membrane transplant, the examination with the slit lamp remains essential, hence allowing to appreciate the formation of the anterior chamber, the presence of a Seidel, the epithelialization of the amniotic membrane and the stability of the thickness of the corneal stroma.
Optical coherence tomography (OCT) of the anterior segment is an imaging technique that allows real-time, goodresolution images of the entire anterior chamber and cornea (11).
The OCT is usually performed before surgery allowing the examination of morphological parameters of the receptor cornea and ulcer (size, depth) (12) (13). OCT has also tremendous benefits in the case of keratitis since it allows an accurate appreciation of necrosis and infiltration areas (14)  The demarcation line remains visible at OCT until the third month in the form of a hyper-reflective line between the transplanted amniotic membrane and the residual corneal stroma. Subsequently, the demarcation line becomes less visible and the amniotic tissue could no longer be distinguished from the surrounding corneal stroma (18). Monitoring by OCT complements clinical monitoring and makes better quantification of corneal thickness, which tends to decrease before stabilizing around the 6th month (15.18).

Conclusion:-
Immune pathologies of the cornea have in common the immune-like inflammation of the cornea. Therapeutic management must be rapid because the anatomical and functional integrity of the globe is often threatened.
Our study demonstrate clearly that the amniotic membrane transplantation remains the best surgical alternative in the management of deep or pre-perforative ulcers. Its integration with corneal thickness is always associated with the re-epithelialization. The OCT is therefore the best assessment to monitoring the integration of this membrane.