New research published in Graefe’s Archive for Clinical and Experimental Ophthalmology offers updated insight into the current prevalence of keratoconus—starkly contrasting with previous, long-held estimates.
Give me some background.
Going back to 1986, keratoconus has been considered a rare corneal disease with a varying prevalence in the literature estimated between 1 in 20 to 1 in 2,000.
However, more recent reports across the globe have been scattered and seemingly dependent on varying factors such as gender and ethnicity or sample sizes and selection, diagnostic methods, and disease definitions.
Thus, researchers have been unable to come to a universal consensus on keratoconous’s prevalence.
Now this research.
Investigators conducted a prospective, population-based cohort study (the Gutenberg Health Study [GHS]) in Germany from 2012 to 2017.
At a 5-year follow-up, 12,423 Caucasian participants (ages 40 to 80) underwent a detailed medical history and general exam, as well as an ophthalmic exam that included Scheimpflug imaging (Pentacam, Oculus).
How did they test for keratoconus?
Two ophthalmologists performing a masked double grading on the corresponding imaging, in which they analyzed the axial / sagittal images of the anterior and posterior corneal surface, pachymetry, keratoconus indices, and the Belin/Ambrósio Enhanced Ectasia Display.
Investigators used an automatic analysis (via the Pentacam) based on the Amsler classification.
Go on …
Researchers assessed potential associations between keratoconus with age, sex, body mass index (BMI), thyroid hormone, smoking, diabetes, arterial hypertension, atopy, steroid use, sleep apnea, allergies, and asthma.
And the result?
Out of 10,419 German participants, 75 eyes (51 participants; 0.49%) were classified with keratoconus.
Based on this, the prevalence of keratoconus among a Caucasian population is closer to 1:200.
Disease prevalence was distributed fairly equally across four age groups:
- 40–49 years: 0.49%
- 50–59 years: 0.55%
- 60–69 years: 0.51%
- 70–80 years: 0.44%
Further, no major differences were noted between genders: male (0.52%) vs female (0.45%)
What about the other factors?
Per logistic regression, no association was found between keratoconus and any of the tested factors (listed above).
Expert feedback?
Based on the data findings, the study authors recommended that large population-based studies are needed in order to assess the burden of disease. “In our experience, the numbers of patients in ophthalmologic practices and clinics are increasing significantly, suggesting that the prevalence may be much higher,” they wrote.
Takeaway?
The authors concluded that, among the studied German population, the prevalence of keratoconus is an estimated tenfold higher than previous research have reported.
They stated that the design of the study and technology used (Scheimpflug imaging) “enables a reliable statement on the prevalence and association with possible risk factors.”