In cases of patients with mild or no symptoms, accurate identification can be challenging using only equipment-based tests like corneal CT or slit lamp examinations. In fact, there have been global reports of patients with no observable signs of corneal opacity during equipment-based tests who developed small, sand-like, whitish deposits around the flap post-surgery. Therefore, conducting genetic tests before surgery to accurately diagnose the condition is crucial.

1. [1] Yu-Chih Hou et al., Phenotype&genotype correlations in patients with TGFBI-linked corneal dystrophies in Taiwan, Molecular Vision 2012 18:362-371
2. [2] C Chao-Shem et al. Post-LASIK exacerbation of granular corneal dystrophy type 2 in members of a Chinese family,
3. [3] Extremely varied phenotypes in granular corneal dystrophy type 2 heterozygotes, Molecular Vision 2012 18:1755-1762
4. [4] Zhang FJ et al., Whether does the granular corneal dystrophy indicate for the excimer laser ablation surgery or not, Chin J Ophthalmol, 2011 Jul; 47(7); 580-3

While corneal dystrophy is commonly known to occur around adolescence, the onset can vary due to individual genetic differences and environmental factors. Cases of mutation carriers in their 30s to 70s without symptoms have been reported. Moreover, UV-blocking lenses or glasses may delay the onset of the disease, leading to asymptomatic cases among those preparing for refractive surgery. Thus, it is advisable to conduct genetic testing to confirm the disease(mutation presence) for safety accurately.

1. [1] Reduced penetrance in familial Avellino corneal dystrophy associated with TGFBI mutations, Mol Vis. 2009: 15:70-75
2. [2] Extremely varied phenotypes in granular corneal dystrophy type 2 heterozygotes, Mol Vis. 2012; 18:1755-1762
3. [3] Analysis of TGFBI gene mutations in Chinese patients with corneal dystrophies and review of the literature, Mol Vis, 2010; 16:1186-1193

No, that’s not the case. Sixty-three genetic mutations associated with corneal dystrophies have been discovered in 30 countries. Among these, the most frequently reported worldwide are GCD1, GCD2, LCD1, RBCD, and TBCD. In fact, recent studies from China have reported finding four corneal dystrophy mutations in addition to Avellino Corneal Dystrophy.

1. [1] TGFBI Gene mutation analysis of clinically diagnosed granular corneal dystrophy patients prior to PTK :A pilot study from Eastern China, Scientific Reports. 7:596
2. [2] Pathogenesis and treatments of TGFBI corneal dystrophies, Retinal and Eye Research 50 (2016)67-88

Sixty-three genetic mutations have been reported globally to be associated with corneal dystrophies. Among the five types of corneal dystrophy most frequently reported worldwide, Granular Corneal Dystrophy Type 2 has an established prevalence rate, with 1 in 870 people in Korea carrying the mutation. This equates to an estimated 57,000 individuals with the genetic mutation in Korea’s population. The cases of other four types of corneal dystrophies continue to be reported globally, but studies of exact prevalence have yet to be reported to date.

Most early-stage corneal dystrophy patients have clear corneas, and even in manifested cases, the degree of expression can vary due to individual lifestyle factors and lens wearing period, making it difficult to obtain accurate results. However, genetic testing allows for precise assessment even in patients who are challenging to diagnose with equipment-based tests. Many textbooks and literature also specify that individuals carrying corneal dystrophy-associated genetic mutations should avoid refractive surgeries like LASIK and LASEK.

1. [1] Robert A Copeland Jr., Natalie A Afshari copeland and afshari principles and practice of cornea Pg. 777, 2013 (1st edition)
2. [2] Traboulsl, Elias, Genetics Disease of the Eye, 2nd Edition, Pg. 267

Implantable Collamer Lens surgery involves inserting a specially designed lens behind or in front of the iris without cutting the cornea to correct vision. Although this does not directly affect the corneal stroma, the procedure still involves creating a 2.8 to 3.2 mm incision in the cornea. Hence, it is not 100% safe. Therefore, checking for corneal dystrophy mutations through genetic testing before surgery is advisable.

Corneal dystrophy is fundamentally a genetic disorder. However, even if no family members or relatives have corneal dystrophy mutations, the individual can be the first to develop these mutations, which may be passed on to future generations. Therefore, it’s advisable to undergo genetic testing before procedures like LASIK and LASEK.

If one parent carries the corneal dystrophy mutation gene, there is a 50% chance of this dominant gene being inherited by their children. Therefore, it is possible for children not to carry the mutation even if a parent does.

Although corneal dystrophy can be identified with equipment-based tests, these tests may not be accurate for patients with mild or no symptoms. Therefore, using genetic testing for precise diagnosis is recommended. For example, a 23-year-old patient carrying the corneal dystrophy mutation showed no symptoms when examined with a slit lamp.

Unfortunately, there is currently no cure for corneal dystrophy. Once diagnosed, the best approach is preventive measures to avoid physical damage to the cornea and regular monitoring.

While Phototherapeutic Keratectomy(PTK) can temporarily treat corneal dystrophy by removing part of the clouded corneal layer, the condition can recur over time, as seen in cases where more severe opacity occurs after the surgery. Therefore, it is essential to delay the onset and progression of the disease as much as possible.

1. [1] Homozygous granular corneal dystrophy type II (Avellino corneal dystrophy): natural history and progression after treatment. Cornea 2007;26:1095-100.
2. [2] Pathogenesis and treatments of TGFBI corneal dystrophies, Retinal and Eye Research 50, 2016; 67-88

• 1 It is advisable to avoid refractive surgeries like LASIK and LASEK.
• 2 To slow the progression of the disease, it is vital to avoid external irritants like UV rays. Wearing UV-protective eyewear or wide-brimmed hats is recommended during outdoor activities.
• 3 Be cautious to prevent eye injuries in daily life and during physical activities.
• 4 Regular use of artificial tears is recommended.

1. [1] Corneal Dystrophy and Disease: Diagnosis and Management, Contact Lens Spectrum, Issue: 2010. Dec.
2. [2] Corneal Dystrophy Treatment, American Academy of Ophthalmology, 2015. Oct. 14