The cornea – the clear window at the front of the eye – normally measures around 550 µm at its centre. The corneas of the 7-year-old girl described in the August 2026 issue of Cataract & Refractive Surgery Today (CRST) measured barely 330 µm, and they were also strikingly steep. Four corneal specialists were asked how they would manage these enigmatically ultrathin corneas. Among them was ELZA’s Medical Director, Prof. Farhad Hafezi, MD, PhD, FARVO. Their answers, published in CRST’s Refractive Surgery Case Files series, show how leading experts reason through a case with no textbook answer.

An unusual case of ultrathin corneas

The article, “Enigmatically Ultrathin, Steep Corneas”, was prepared by the series editor, Prof. Suphi Taneri of Münster, Germany. Commentary came from Prof. Claus Cursiefen of Cologne, Prof. George Kymionis of Athens, and Prof. Hafezi. The patient first came for a consultation at the age of 7. She was healthy, had no family history of eye disease, and was patching one eye to treat amblyopia – reduced vision in an eye that has never learned to see sharply. Almost everything in her examination was normal. However, corneal imaging told a different story. Both corneas were uniformly ultrathin and very steep, with 4.5 to 6 dioptres of regular astigmatism – an uneven corneal curvature that blurs vision.

What the expert panel considered

For Prof. Cursiefen, the most likely diagnosis was brittle cornea syndrome. This rare genetic connective tissue disease leaves the cornea extremely thin and at risk of rupture after minor trauma. Consequently, he recommended genetic testing and counselling, protective eyewear, and avoiding risky sports. Prof. Kymionis instead favoured a congenital – present from birth – diffuse corneal thinning or steepening, with keratoglobus high on his list. He advised conservative management: full spectacle correction first, then possibly rigid or scleral contact lenses later. Impact-resistant polycarbonate spectacle lenses would add protection, and he would avoid corneal surgery of any kind.

Prof. Hafezi’s view, stabilise early with cross-linking

Prof. Hafezi also read the pattern as early keratoglobus, a rare condition related to keratoconus. In keratoglobus, the entire cornea – not just a localised zone – thins and steepens. Both belong to the corneal ectasias, diseases in which the cornea progressively weakens and bulges, and in children, ectasias can progress quickly. Corneal cross-linking (CXL) is a treatment that stiffens the cornea using riboflavin (vitamin B2) drops and UV-A light. His group was the first to propose performing it immediately in paediatric ectasia, rather than waiting for documented progression. That approach has since gained the formal support of the Second Global Consensus on Keratoconus.

Corneas this thin, however, fall far below the roughly 400 µm minimum that conventional CXL protocols require. For exactly these situations, his team developed the ELZA-sub400 protocol, an individualised form of cross-linking published in the American Journal of Ophthalmology. It adjusts the UV-A dose so that ultrathin corneas can be treated to a calculated stromal depth of approximately 214 µm. The technique has also been applied to keratoglobus. After a complete corneal work-up, Prof. Hafezi wrote, he would perform CXL to stabilise the girl’s condition. Specialty contact lenses, where feasible, and close monitoring of her amblyopia would follow.

What actually happened over ten years

Prof. Taneri, who has followed the patient since 2016, chose a different path: close observation with regular corneal imaging. At the time she first presented, he noted, no cross-linking protocols suited to such extremely thin corneas were yet available. A decade later, her corneas have remained stable. Her most recent examination, in May 2026, showed healthy corneal cell counts, normal eye length, and no clinical signs of a connective tissue disorder. Because her vision with glasses remained satisfactory, he decided against contact lenses for now, as fitting them could traumatise potentially fragile corneas. From the age of 18, a lens implanted inside the eye (a phakic IOL) could reduce her dependence on strong glasses.

On one point, Prof. Kymionis and Prof. Taneri were emphatic. Ultrathin corneas are a firm contraindication for any corneal refractive or ablative surgery, including laser vision correction.

Cases like this one show why very thin corneas need specialist assessment before any treatment decision. Prof. Hafezi and the ELZA team assess and treat thin and ectatic corneas at the ELZA Institute, including cross-linking for thin corneas using the ELZA-sub400 protocol. The full case discussion is available on the CRST website.

References

  • Taneri S, Cursiefen C, Hafezi F, Kymionis G. Enigmatically ultrathin, steep corneas. Cataract & Refractive Surgery Today. August 2026. crstoday.com
  • Hafezi F, Kling S, Gilardoni F, et al. Individualized corneal cross-linking with riboflavin and UV-A in ultrathin corneas, the sub400 protocol. Am J Ophthalmol. 2021;224:133–142. doi:10.1016/j.ajo.2020.12.011