Keratoconus is the most common corneal dystrophy, but it is possible to have more than one corneal dystrophy. If you are living with with both keratoconus and another corneal dystrophy (such as Lattice Dystrophy), obtaining appropriate treatment for your vision loss can be more complicated. While the symptoms of keratoconus often appear in adolescence or early adulthood, Lattice Dystrophy symptoms typically become apparent in early childhood (per Johns Hopkins Medicine). Meanwhile, Granular Corneal Dystrophy symptoms usually appear in afflicted people between 20-30 years of age.
Three of the more than 19 other types of corneal dystrophy besides keratoconus are described below, as well as how your keratoconus treatment may be affected if you are diagnosed with both keratoconus and an additional corneal disorder.
Impact of Fuch’s Dystrophy Diagnosis on Keratoconus Treatment
The second-most common form of corneal dystrophy is Fuch’s Dystrophy, but its symptoms do not usually appear before middle-age. However, the American Academy of Ophthalmology notes that around 30 percent of people with Fuch’s Dystrophy will eventually require surgery. A common early symptom is blurring of vision upon awakening in the morning – with subsequent lessening of blurred vision throughout the day. As this particular corneal disorder progresses, a sensation of a foreign body in the eye is often experienced by people living with Fuch’s Dystrophy.
According to an article in EyeWorld, surgery involving correction of a refraction abnormality in patients with both keratoconus and Fuch’s Dystrophy is more difficult than in patients coping with only one of these corneal disorders. Therefore, determining whether you have both keratoconus and Fuch’s Dystrophy is important before undergoing cornea-involved surgery to correct your worsening eyesight.
Understanding Lattice Dystrophy
The National Organization for Rare Diseases (NORD) characterizes Lattice Dystrophy as a stromal corneal dystrophy (rather than a different type of corneal dystrophy), and describes two variants of this genetic disorder. However, both variants are characterized by the development of lattice-like lesions on the cornea. Keratoplasty surgery (such as a cornea transplant) is often needed in people living with Lattice Dystrophy – although a daily eye drop regimen may be prescribed as the sole treatment earlier in the progression of Lattice Dystrophy.
Three other stromal corneal dystrophies are:
- Granular Corneal Dystrophy (Types 1 and 2);
- Macular Corneal Dystrophy;
- Schnyder Crystalline Corneal Dystrophy
Posterior Polymorphous Dystrophy
This rare type of corneal dystrophy is genetic, and can be asymptomatic if recessively-triggered. Characterized by alterations of the Descemet membrane and the corneal endothelium, corneal clouding may develop in people afflicted with this type of posterior corneal dystrophy.
However – if autosomal dominantly-inherited – Posterior Polymorphous Dystrophy is typically present at birth and symptomatic. Meanwhile, ocular pressure can become increased in people living with Posterior Polymorphous Dystrophy (resulting in an increased risk for the development of glaucoma).
According to the National Center for Biotechnology (NCBI) website, the following are three different genetic mutations identified as causing Posterior Polymorphous Dystrophy:
Notably, an article in 2018 the American Journal of Human Genetics reported a genetic mutation in GRHL2 as another potential underlying cause of the autosomal-dominant form of Posterior Polymorphous Dystrophy.
Can You Wear Contact Lenses if You Have Keratoconus and Another Cornea Disorder?
If you have keratoconus and another cornea disorder, you may still be able to wear Rigid Gas Permeable (RGP) contact lenses or scleral contact lenses depending upon the severity of your symptoms. However, identifying whether you have both keratoconus and another cornea disorder can impact whether contact lenses will be sufficient to manage the impact of your cornea disorders in future. Therefore, determining whether you have more than one cornea disorder (and not solely keratoconus) can aid in developing an optimal treatment plan.
Visiting an office of the Precision Keratoconus Center nearest to your place of residence makes excellent sense if you have been diagnosed with keratoconus.