EyeWorld Asia-Pacific June 2024 Issue

CORNEA

Physician Perspective: Why are cornea specialists failing patients with limbal stem cell deficiency?

by Edward Holland, MD, and Albert Cheung, MD

Despite breakthroughs in our ability to manage severe ocular surface disease (OSD) with Limbal Stem Cell Deficiency (LSCD) effectively both medically and surgically, the majority of patients with this condition are either not treated at all, or appropriately. Safe and effective treatment options with Ocular Surface Stem Cell Transplantation with Systemic Immunosuppression (OSSTx with SI) have been developed and presented at major meetings, in peer-reviewed journals as well as textbooks. Techniques and protocols for OSSTx with SI have been published for more than 25 years. 1–6 Despite this, only a few corneal specialists have adopted these treatments, and many of these patients are not referred to the few centers that perform these procedures. Misdiagnosis and mismanagement of these patients are sadly all too common. This has led to the inappropriate application of penetrating keratoplasty or keratoprosthesis, often worsening an already bad situation. While it is difficult to assess the exact prevalence of LSCD, approximately 1–5 per 10,000 has been estimated. 7 Given the U.S. population of greater than 335 million, that would affect approximately 33,500 to 167,500 people. Too often, LSCD patients are only medically managed based on a diagnosis of dry eye disease or viral keratitis. When they are managed surgically, substandard surgeries are commonly offered. Superficial keratectomy (with

or without amniotic membrane) and phototherapeutic keratectomy can buy time with only short-term visual improvement for mild disease with anterior stromal scarring. 8 Ultimately, this strategy will be unsuccessful, as it fails to address the underlying problem of limbal stem cell failure. Penetrating Keratoplasty (PK) is the most common erroneously applied corneal procedure we encounter for total LSCD patients. 8 Corneal specialists should be well aware that there is no chance of long-term success with a primary PK for these patients. 1,8–10 The total LSCD leads to a failed PK due to ocular surface failure, inflammation, and neovascularization of the cornea with subsequent rejection and worse vision. 8,11 Many corneal specialists perform the Boston keratoprosthesis (KPro) for LSCD. Overall, KPros have a reasonable success rate in non-inflamed eyes, such as failed PKs or high-risk PKs due to immunologic reasons. However, KPro for LSCD is a different story. Studies have noted worse KPro outcomes in the setting of LSCD and OSD. In a large multicenter cohort of Boston type 1 KPro eyes, Srikumaran et al. noted the following rates of sterile corneal necrosis (19.5%), retinal detachment (18.6%), endophthalmitis (15.5%), and infectious keratitis (without endophthalmitis, 3.4%) for all KPro eyes. 12 They noted that in eyes with severe OSD (defined as severe keratoconjunctivitis sicca, LSCD, and cicatrizing conjunctivitis) had significantly lower retention rates (35%

Chemical injury with severe symblepharon and total limbal stem cell deficiency.

Two years postoperative after a living-related conjunctival limbal autograft and keratolimbal allograft with subsequent PK.

Sixteen years postoperative after a living-related conjunctival limbal autograft and keratolimbal allograft with subsequent PK.

Chemical injury with conjunctival scarring, total limbal stem cell deficiency and failed PK.

Twenty years postoperative after a living-related conjunctival limbal allograft and keratolimbal allograft. Source (all): Edward Holland, MD.

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EyeWorld Asia Pacific | June 2024