Review of Surgical Strategies for Ocular Surface Disease

Dua H.S., Miri A., Said D.G.

Conjunctivalization of the cornea is the hallmark of limbal stem cell deficiency (LSCD). This is often associated with persistent corneal epithelial defects and a fibrovascular pannus. LSCD can be unilateral or bilateral and partial or total. In partial LSCD involving the visual axis sequential sector conjunctival epitheliectomy (SSCE) is a useful option. In total LSCD, transplantation of limbal tissue or of ex vivo expanded sheets is the mainstay. In unilateral cases autolimbal transplant is the procedure of choice. In bilateral cases living (related) and cadaver donors are considered. The former has the advantage of being fresh and can be human leucocyte antigen matched. Procedures for harvesting limbal tissue from living donors are identical. Different strategies are required for harvesting tissue from cadaver whole globes or sclero-corneal rims. Recipient eye preparation requires removal of the fibrovascular tissue. Donor explants are generally sutured directly on the denuded recipient surface without the preparation of a 'bed' to fit the explant. It is imperative that inflammation is meticulously controlled before limbal transplantation especially if tissue from living donors is used. Limbal transplantation, with the exception of a corneal graft, should be the last surgical intervention planned. Meticulous postoperative care and treatment with antibiotics, steroids, artificial tears and autologous serum are required. With allografts long-term immunosuppression is necessary. Limbal transplantation is contraindicated in the presence of severe dry eye. Despite its complexities limbal transplantation does significantly improve vision related quality of life. Autografts give the best results and living related donor grafts are next best. Majority of cadaver grafts fail in 5 years.

Letko E.

To determine the effect of amniotic membrane transplantation (AMT) on persistent corneal epithelial defects (PEDs) and to compare the efficacy between inlay and overlay techniques.Thirty patients (30 eyes) underwent AMT for PED. The use of AMT was restricted to patients in whom all previous measures, including bandage contact lens and tarsorrhaphy, had failed. The amniotic membrane was placed on the surface of the cornea in overlay (group A) or inlay (group B) fashion.The PED healed after the first AMT in 21 eyes (70%) within an average of 25.5 days after surgery and recurred in 6 eyes (29%). Among the 22 eyes treated with an overlay AMT (group A), the PED healed after the first AMT in 14 eyes (64%) within an average of 24.5 days and recurred in 4 eyes (29%). Among the 8 eyes treated with an inlay AMT (group B), the PED healed within an average of 27.4 days after AMT, which did not statistically significantly differ from group A (P = .72). The PED healed after the first AMT in 7 eyes (88%) and recurred in 2 (29%) of 7 eyes.The AMT can be helpful in the treatment of PED in which all other conventional management has failed. However, the success rate in our study was not as high as that previously reported, and our results showed a high incidence of recurrences of epithelial defects. We did not find any difference between overlay and inlay techniques in terms of healing time and recurrence rate.

Tsubota K., Satake Y., Kaido M., Shinozaki N., Shimmura S., Bissen-Miyajima H., Shimazaki J.

Conditions that destroy the limbal area of the peripheral cornea, such as the Stevens-Johnson syndrome, ocular pemphigoid, and chemical and thermal injuries, can deplete stem cells of the corneal epithelium. The result is scarring and opacification of the normally clear cornea. Standard corneal transplantation cannot treat this form of functional blindness.We performed and evaluated 70 transplantations of corneal epithelial stem cells from cadaveric eyes into 43 eyes of 39 patients with severe ocular-surface disorders and limbal dysfunction. Medical treatment had failed in all patients. The patients had a mean preoperative visual acuity of 0.004 (only being able to count the number of fingers presented by the examiner) in the affected eyes, which satisfies the criteria for legal blindness in most countries. In 28 eyes, we also performed standard corneal transplantation. Stem-cell transplantations were performed as many as four times on 1 eye if the initial results were not satisfactory; 19 eyes had multiple transplantations. Patients were followed for at least one year after transplantation.A mean of 1163 days after stem-cell transplantation, 22 of the 43 eyes (51 percent) had corneal epithelialization; of the 22 eyes, 7 eyes had corneal stromal edema and 15 eyes had clear corneas. Mean visual acuity improved from 0.004 to 0.02 (vision sufficient to distinguish the largest symbol on the visual-acuity chart from a distance of 1 m) (P

TSENG S.C., TSUBOTA K.

To outline important concepts for treating ocular surface and tear disorders.A review was conducted of recently published findings.Five concepts were delineated: ocular surface health is ensured by a close relationship between ocular surface epithelia and the preocular tear film; a stable tear film is inherently maintained by external adnexae; the intact protective mechanism is controlled by effective neuroanatomic integration; corneal epithelial stem cells are located at the corneoscleral limbus; and ocular surface epithelial cell function is supported by stromal fibroblasts and matrix.These concepts stress that ocular surface epithelia and the preocular tear film function as a unit and, furthermore, that several corneal and external diseases can be categorized as ocular surface and tear disorders. These concepts also help one formulate unified diagnostic and therapeutic strategies for management of these diseases.

LEE S., TSENG S.C.

To determine whether preserved human amniotic membrane can be used as an alternative substrate for treating persistent corneal epithelial defects with sterile ulceration.Amniotic membrane transplantation was performed in 11 eyes of 11 consecutive patients with corneal ulcers of different causes that had persisted for a mean +/- SD of 17.5 +/- 13.9 weeks.Ten patients healed in 3.9 +/- 2.3 weeks (P < .01) without recurrence for 9.0 +/- 5.9 months. One patient failed to heal because of preexisting corneal perforation pursuant to severe rheumatoid arthritis.Amniotic membrane transplantation may be considered an alternative method for treating persistent epithelial defects and sterile ulceration that are refractory to conventional treatment and before considering treatment by conjunctival flaps or tarsorrhaphy.

Keivyon K.R., Tseng S.C.

Limbal autograft transplantation is presented in 26 consecutive cases comprising both acute and chronic chemical injury (20 cases), thermal burns (2 cases), contact lens-induced keratopathy (3 cases), and ocular surface failure after multiple surgical procedures (1 case), with follow-up ranging from 2 to 45 months (mean, 18 months). The operative technique usually involved transfer of two free grafts of limbal tissue from the uninjured or less injured donor eye to the severely injured recipient eye, the latter having been prepared by limited conjunctival research and superficial dissection of fibrovascular pannus without keratectomy. Clinical results in 21 patients with follow-up of 6 months or more have consistently shown improved visual acuity (17 cases), rapid surface healing (19 cases), stable epithelial adhesion without recurrent erosion or persistent epithelial defect (20 cases), arrest or regression of corneal neovascularization (15 cases), and probable increased success for lamellar or penetrating keratoplasty (8 cases). No intraoperative complications were encountered, and no adverse reactions developed in donor eyes. Impression cytology in selected cases showed restoration of the corneal epithelial phenotype and regression of goblet cells from the recipient cornea. Therefore, limbal autograft transplantation is recommended for treatment of widespread ocular surface damage with loss of limbal epithelial stem cells and, specifically, for chemical or thermal burns, contact lens-induced keratopathy, and selected persistent corneal epithelial defects.

Kenyon K.R., Wagoner M.D., Hettinger M.E.

Abstract The technique and results of conjunctival autograft transplantation for advanced and recurrent pterygium are presented for 57 eyes of 54 patients. The pterygia were primary in 16 eyes and recurrent in 41; among the latter group, 14 patients had diplopia resulting from cicatricial involvement of the medial rectus muscle. In all cases, free conjunctival grafts from the superotemporal bulbar conjunctiva of the same eye were used to resurface exposed sclera and extraocular muscle. There were no intraoperative complications. Postoperative follow-up ranges from 1 to 67 months, with a mean of 24 months. Only three pterygia have recurred (5.3%); two were successfully remedied by a second conjunctival autograft, whereas the third did not require an additional procedure. In all 14 patients with diplopia, extraocular movement was restored. We recommend this surgical approach as a safe and effective means of treating pterygia complicated by conjunctival scarring with extraocular muscle involvement and requiring concurrent fornix reconstruction.