Fuchs’ Dystrophy: An Overview

Moussa Al-Rufayie

Introduction

Fuchs’ dystrophy, a progressive disorder affecting the cornea, is a condition characterised by the gradual deterioration of endothelial cells in the cornea, leading to vision impairment and, in severe cases, blindness. Ernst Fuchs, an Austrian ophthalmologist, first described the dystrophy in 1910 (1). His detailed observations laid the groundwork for understanding the disease’s clinical and pathological features. Initially, there were no effective treatments, and patients often faced significant vision loss. The primary management strategies involved symptomatic relief through hypertonic saline drops and ointments to reduce corneal oedema temporarily (2).

Pathophysiology of Fuchs’ Dystrophy

The cornea, a transparent, dome-shaped surface that covers the front of the eye, is vital for vision. It functions as the eye’s outermost lens, contributing significantly to focusing incoming light (3). The cornea is composed of five layers: the epithelium, Bowman’s layer, stroma, Descemet’s membrane, and the endothelium. The endothelium, a single layer of cells on the inner surface, is crucial for maintaining corneal transparency by regulating fluid and solute transport between the cornea and the aqueous humour (3).

In Fuchs’ dystrophy, the endothelial cells progressively die off, leading to an accumulation of fluid within the cornea, known as corneal oedema. This fluid buildup causes the cornea to swell and become cloudy, resulting in impaired vision (1). The disease typically presents in multiple stages. In the early stage, individuals may experience blurred vision, especially upon waking. As the disease progresses, the symptoms worsen, leading to constant visual impairment and pain due to the formation of epithelial blisters on the cornea’s surface (1,4).

The endothelial cells of the cornea are responsible for pumping excess fluid out of the stroma, maintaining the cornea’s dehydrated state and thus its transparency. This fluid regulation is achieved through ion transport mechanisms and water channels known as aquaporins (5). In Fuchs’ dystrophy, the dysfunction and loss of endothelial cells impair this pump function, leading to fluid accumulation in the corneal stroma (4).

Aetiology and Pathogenesis

The exact cause of Fuchs’ dystrophy remains unclear, although genetic factors play a significant role. It often runs in families, indicating a hereditary component. Mutations in certain genes, such as COL8A2 and SLC4A11, have been associated with the disease (6). Environmental factors and ageing also contribute to the onset and progression of Fuchs’ dystrophy (7).

Presentation

Patients with Fuchs’ dystrophy typically present with blurred vision that is worse in the morning and gradually improves throughout the day. This fluctuation is due to the accumulation of fluid in the cornea during sleep, which decreases as the eye remains open and the fluid evaporates. As the disease progresses, vision becomes consistently blurry, and patients may experience pain, glare, halos around lights, and sensitivity to light (2).

Diagnosis & Investigations

The diagnosis of Fuchs’ dystrophy is primarily clinical, based on patient history and slit-lamp examination. Key findings include corneal guttata (tiny wart-like excrescences on the endothelium) and stromal oedema (2). Advanced stages may show subepithelial bullae (blisters) and corneal scarring (4). Specular microscopy can be used to assess endothelial cell density and morphology, while optical coherence tomography (OCT) helps in visualising corneal thickness and structure (8).

Management

The introduction of corneal transplantation in the mid-20th century marked a significant advancement (9). Penetrating keratoplasty (PK), a full-thickness corneal transplant, became the standard procedure.

The first successful Corneal transplant, or penetrating keratoplasty (PK) was performed by Eduard Zirm in 1905 (9). This procedure became a significant advancement in the treatment of corneal diseases, including Fuchs’ dystrophy, providing a pathway to restore vision in affected patients. However, PK was associated with long recovery times and complications such as graft rejection (10).

In recent years, endothelial keratoplasty (EK) techniques, such as Descemet’s stripping endothelial keratoplasty (DSEK) and Descemet’s membrane endothelial keratoplasty (DMEK), have revolutionised treatment (11). These methods involve selectively replacing the diseased endothelial layer while preserving the healthy corneal tissue, leading to faster recovery and fewer complications (12).

Treatment-related complications also exist. Penetrating keratoplasty carries risks such as graft rejection, infection, and astigmatism (13). Although EK techniques have reduced these risks, potential complications include graft detachment, primary graft failure, and the need for repeat surgeries (12).

Conclusion

Fuchs’ dystrophy, once a mysterious and debilitating disease, has seen significant advancements in understanding and treatment over the past century. Ongoing research into its genetic basis and the development of novel therapeutic approaches continue to improve outcomes for patients. Early diagnosis and advancements in surgical techniques offer hope for preserving vision and enhancing the quality of life for those affected by this challenging condition.

References

  1. Eghrari AO, Gottsch JD. Fuchs’ corneal dystrophy. Expert Review of Ophthalmology [Internet]. 2010 Apr;5(2):147–59. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897712/
  2. Majid Moshirfar, Somani AN, Uma Vaidyanathan, Patel BC. Fuchs Endothelial Dystrophy (FED) [Internet]. Nih.gov. StatPearls Publishing; 2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545248/
  3. Sridhar MS. Anatomy of cornea and ocular surface. Indian journal of ophthalmology [Internet]. 2018 Feb;66(2):190–4. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5819093/
  4. Nanavaty MA, Wang X, Shortt AJ. Endothelial keratoplasty versus penetrating keratoplasty for Fuchs endothelial dystrophy. Cochrane Database of Systematic Reviews. 2014 Feb 14; Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4260402/
  5. Kenney MC, Atilano SR, Zorapapel N, Holguin B, Gaster RN, Ljubimov AV. Altered expression of aquaporins in bullous keratopathy and Fuchs’ dystrophy corneas. The Journal of Histochemistry and Cytochemistry: Official Journal of the Histochemistry Society [Internet]. 2004 Oct 1 [cited 2024 Jun 17];52(10):1341–50. Available from: https://pubmed.ncbi.nlm.nih.gov/15385580/
  6. Nanda GG, Alone DP. REVIEW: Current understanding of the pathogenesis of Fuchs’ endothelial corneal dystrophy. Molecular Vision [Internet]. 2019 Jun 5;25:295–310. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6571125/
  7. Chang YS, Ho CH, Wang JJ, Tseng SH, Jan RL. The Sociodemographic and Risk Factors for Fuchs’ Endothelial Dystrophy: A Nationwide, Matched Case–Control Study in Taiwan. Journal of Personalized Medicine. 2022 Feb 18;12(2):305. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8877330/
  8. Iovino C, Fossarello M, Giannaccare G, Pellegrini M, Braghiroli M, Demarinis G, et al. Corneal endothelium features in Fuchs’ Endothelial Corneal Dystrophy: A preliminary 3D anterior segment optical coherence tomography study. Malik RA, editor. PLOS ONE. 2018 Nov 29;13(11):e0207891. Available from: https://pubmed.ncbi.nlm.nih.gov/30496218/
  9. Güell JL, El Husseiny MA, Manero F, Gris O, Elies D. Historical Review and Update of Surgical Treatment for Corneal Endothelial Diseases. Ophthalmology and Therapy [Internet]. 2014 Dec 1 [cited 2021 Apr 22];3(1-2):1–15. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4254859/
  10. Gurnani B, Kaur K. Penetrating Keratoplasty [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2023. Available from: https://www.ncbi.nlm.nih.gov/books/NBK592388/
  11. Tandon R, Singh R, Gupta N, Vanathi M. Corneal transplantation in the modern era. Indian Journal of Medical Research [Internet]. 2019;150(1):7. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6798607/
  12. Moshirfar M, Thomson AC, Ronquillo Y. Corneal Endothelial Transplantation [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK562265/
  13. Mukhija R, Henein C, Lee H, Phee J, Nanavaty MA. Outcomes of Descemet’s membrane endothelial keratoplasty performed in combination with, before, or after cataract surgery in Fuchs’ endothelial dystrophy: A review of the literature and meta-analysis. Indian Journal of Ophthalmology [Internet]. 2023 Mar 1 [cited 2024 Jun 17];71(3):707–16. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10230002/
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