Corneal disease

Keratoconus — slow it down, stabilize it, restore vision

Keratoconus is a degenerative disease of the cornea that gradually deforms it into a cone shape. Today, this condition can be stabilized in the vast majority of cases with appropriate care.

My research work at the Paris Hospitals on eye rubbing — a key causal factor — underpins the comprehensive care I offer at the practice: from precise topographic and tomographic diagnosis (Anterion) to corneal cross-linking (CXL), which slows progression, as well as intracorneal ring segments and scleral lenses to restore functional vision.

Rubbing = modifiable cause Anterion (swept-source OCT) UV-A cross-linking ICRS ring segments Scleral lenses DALK transplant if needed
Diagram illustrating keratoconus: cone-shaped corneal deformation and stromal thinning
Mechanism

Understanding keratoconus

A progressive disease of the corneal collagen — but not an inevitable one. Here is what actually happens in your eye.

Definition

Keratoconus is an ectatic disease of the cornea — in other words, a progressive deformation. The stromal collagen loses its strength and the cornea thins, especially in its inferotemporal part. It then takes on a cone shape, instead of keeping its regular dome curvature.

This deformation produces irregular astigmatism that cannot be corrected with conventional glasses, and a progressive loss of vision that can become disabling.

Epidemiology

  • Prevalence: long estimated at about 1 in 2,000 (Kennedy 1986), it is considerably higher in recent studies. The Dutch cohort of Godefrooij 2017 reports ~1 in 375; the Hashemi 2020 meta-analysis found a highly variable prevalence (≈ 138 per 100,000 on average, range 0.07-2.3% depending on the populations studied, higher in some Middle Eastern populations).
  • Onset: between ages 15 and 35, the most critical phase for progression.
  • Course: rapid during the first 10 to 20 years, followed by gradual stabilization around ages 35-40.
  • Sex: slight male predominance.

Mechanism

Keratoconus results from an alteration of the stromal collagen. The exact causes are only partly understood, but several factors contribute to weakening the cornea:

  • Genetic factor: family predisposition (20-30% of cases)
  • Eye rubbing: a major modifiable cause (see dedicated section below)
  • Eye allergy: chronic inflammation with release of proteases
  • Dry eye disease: destabilization of the tear film
  • Atopic background: eczema, asthma, allergic rhinitis

Why glasses are not enough

Unlike myopia or regular astigmatism, keratoconus creates irregular, fluctuating astigmatism. Spectacle lenses cannot correct this irregular shape: vision remains blurred, distorted and unstable. Only rigid contact lenses (gas permeable or scleral) provide adequate correction.

Dr HAGE's research

Eye rubbing — the major modifiable cause

My research at the CHNO des Quinze-Vingts (Paris) with Prof. Christophe Baudouin documents a central mechanism in the progression of keratoconus.

Why rubbing is a major cause

Chronic eye rubbing is not just an aggravating factor — it is a causal factor. Several mechanisms converge:

  • Direct pressure on the cornea with each rub
  • Local rise in temperature
  • Release of pro-inflammatory cytokines (IL-6, IL-8, TNF-α)
  • Activation of metalloproteinases (MMP-2, MMP-9), which damage collagen
  • Progressive biomechanical weakening of the cornea

The vicious circle of rubbing

Allergy / dry eye → itching → intense rubbing → corneal damage → increased inflammation → itching ↑

This cycle, compounded by a behavioral component that is sometimes addictive, lies at the heart of keratoconus progression.

Associated atopic background

Patients with keratoconus often have an atopic background (Th2 profile): eye allergy (vernal or persistent allergic conjunctivitis), dry eye with meibomian gland dysfunction, eczema, asthma, allergic rhinitis. Treating allergy and dry eye is essential to slow progression.

My scientific work

At the Hôpital National d'Ophtalmologie des Quinze-Vingts (CHNO 15-20, Paris), I contributed to two publications describing the cognitive, behavioral and addictive dimension of eye rubbing in patients with keratoconus:

Hage A, Knoeri J, Leveziel L, Majoulet A, Blanc J-V, Buffault J, Labbé A, Baudouin C. EYERUBBICS: The Eye Rubbing Cycle Study. J Clin Med. 2023;12(4):1529. DOI ↗ · PubMed ↗

Hage A, Knoeri J, Leveziel L, Majoulet A, Buffault J, Labbé A, Baudouin C. From ocular itching to eye rubbing: a review of the literature. J Fr Ophtalmol. 2023;46(2):173-184. DOI ↗ · PubMed ↗

Impact: these studies, discussed in Ophthalmology Times, offer a structured description of the eye rubbing cycle and reinforce the importance of patient education and deliberately breaking the rubbing habit in management.

What this means for you in practice

  • Patient education: learning to stop rubbing (attention-diversion techniques)
  • Treatment of eye allergy and atopy
  • Treatment of dry eye (artificial tears, eyelid hygiene, IPL if MGD)
  • Prevention in children: screening and educating at-risk children
Warning signs

Symptoms — the warning signs

Recognizing the first signs of keratoconus allows earlier and more effective treatment. For an accessible overview, you can also read my article “Keratoconus: diagnosis and treatments explained simply”.

Sign 1

Progressive loss of vision

Vision that deteriorates month after month, regardless of age. Increasing difficulty reading, driving or working on screens.

Sign 2

Prescription that changes often

New glasses several times a year (whereas a stable prescription usually lasts 1 to 2 years), with only ever partial improvement.

Sign 3

Irregular astigmatism

Glasses never fully correct vision. The image is blurred and distorted, and its quality varies with the time of day and lighting conditions.

Sign 4

Double vision / ghosting

Double vision or a shadow around images, especially at low contrast. Light sources show characteristic “streaks.”

Sign 5

Photophobia

Irregular astigmatism causes abnormal light diffraction. Discomfort in bright light; sunglasses are often needed even on overcast days.

Sign 6

Soft contact lens intolerance

Soft lenses slip, do not correct well, and quickly become uncomfortable. Generally, only rigid or scleral lenses provide acceptable vision.

Sign 7

Halos at night

Difficulty driving at night because of halos around lights and headlights. Vision is markedly worse in low light.

Sign 8 — emergency

Acute hydrops (sudden pain)

Rare, in very advanced cases: a break in Descemet's membrane causing sudden pain, corneal edema and loss of vision. Seek urgent care.

When should you see a specialist? If you have at least 2-3 of the signs above, a specialist eye consultation with corneal topography is essential. Do not wait for your vision to deteriorate further.

Do you recognize these symptoms?

Early diagnosis changes everything. A prompt consultation allows a complete topographic assessment and guidance toward the best strategy.

At the practice

Diagnosis — corneal topography and tomography

At the OPHTALIFE practice, I use an Anterion® (Heidelberg Engineering) — an anterior segment swept-source OCT — to precisely characterize your keratoconus and closely monitor how it changes over time.

Core examination

Anterion — topography & tomography

High-resolution swept-source OCT: anterior and posterior elevation maps, full pachymetry, keratometry, and automatic calculation of ectasia indices. 3D imaging of the anterior segment in a few seconds, without contact.

Key indices

KMax, asymmetry, thinnest point

KMax (maximum curvature) flags ectasia. Inferior-superior asymmetry and minimum pachymetry (thinnest point) complete the diagnosis. Combined indices such as BAD-D (Belin-Ambrósio) integrate elevation, thinning and topography.

Biomechanics

ORA & Corvis-ST

The ORA measures corneal hysteresis; the Corvis-ST analyzes how the cornea deforms under an air puff (CBI, Corneal Biomechanical Index). These tests objectively document the biomechanical weakness associated with keratoconus, which is useful for diagnosis and follow-up.

Clinical examination

Refraction and slit lamp

Objective and subjective refraction, and a search for late clinical signs: Vogt's striae, Fleischer ring, Munson's sign, chronic or acute hydrops. Assessment of the tear film and the associated ocular surface.

Forme fruste keratoconus

Screening before refractive surgery

Forme fruste keratoconus is a subclinical form, with no symptoms, detected only on imaging. Every candidate for LASIK, SMILE or PRK undergoes systematic screening: undetected keratoconus treated with laser surgery carries a risk of iatrogenic ectasia.

Monitoring progression

Comparison over time

Tests are repeated at regular intervals (every 3 to 12 months depending on the stage) and compared using difference maps. It is this pattern of progression that guides the decision to perform cross-linking: progressing keratoconus warrants prompt treatment.

How the assessment works: a complete examination (Anterion, biomechanics, refraction, slit lamp) performed during the consultation, with no injection or invasive product. Results are available immediately; I go through them with you on the device screen and give you a written report.

Stages

Classification — the stages of keratoconus

Several systems exist. Here are the most relevant ones for guiding treatment.

Stage KMax (D) Central pachymetry (µm) Spherical equivalent Corneal clarity Symptoms & implications
Stage I
(Mild)
<47 >450 < -6.00 Clear Slightly blurred vision, astigmatism of irregular origin. May be mistaken for simple myopia. Treatment: optical correction, topographic monitoring.
Stage II
(Moderate)
47-52 400-450 -6.00 to -10.00 Clear Significant loss of vision, frequent changes in prescription. Soft lens intolerance. Candidate for cross-linking. RGP or scleral lenses.
Stage III
(Advanced)
52-62 300-400 < -10.00 Clear or slight opacification Severely compromised vision, even with contact lenses. Indication for cross-linking + ICRS ring segments if needed. Close follow-up (every 3-6 months) is mandatory.
Stage IV
(Very advanced)
> 62 <300 Variable Variable central opacity, possible scarring (corneal leukoma) Scarring, possible chronic hydrops. DALK or PK transplant often necessary. Risk of secondary ectasia after previous LASIK.

Amsler-Krumeich classification

In France and Europe, the Amsler-Krumeich classification remains the historical reference and the one most widely used in routine practice. It combines maximum keratometry (KMax), spherical equivalent, central pachymetry and the presence of corneal opacities to define four stages of increasing severity (see table above). It is simple, reproducible and provides a framework for treatment decisions.

ABCD system (Belin)

The more recent ABCD system (Belin & Khachikian) provides a multidimensional view:

Each parameter is scored from 0 to 4. The combined score guides treatment decisions and allows fine monitoring of progression over time.

Key point: classification alone is not enough. What matters most is the pattern of progression. A stage II keratoconus progressing by 1-2 D per year warrants active treatment, whereas a stage III that has been stable for 5 years can be managed conservatively.

Main treatment

Corneal cross-linking (CXL) — slowing progression

A technique validated since Wollensak 2003 (Dresden), corneal cross-linking has significantly improved the prognosis of keratoconus. It aims to halt or slow progression in the vast majority of progressive cases.

Ingredient 1

Riboflavin

Vitamin B2 used as a photosensitizing agent. It soaks into the corneal stroma before illumination.

Ingredient 2

UV-A light

Ultraviolet light at 365 nm, which activates the riboflavin and triggers the photochemical reaction.

Effect

Collagen cross-links

Formation of covalent bonds between collagen fibers: the cornea becomes stiffer and the progression of the cone slows down.

≈ 30 min
Duration of the standard protocol
Progressive
Indication: documented progressive KC
≈ 90%
Reported stabilization at 5 years
12–24 mo
Time to definitive stabilization
Indications
  • Documented progressive keratoconus (progression objectively shown during follow-up)
  • Mainly stages II and III
  • To reduce the risk of hydrops and of progression toward more extensive surgery
  • Ectasia after refractive surgery
  • Pellucid marginal degeneration
Protocol variants
  • Dresden protocol (epi-off): the historical reference since Wollensak 2003
  • Accelerated protocols: shorter duration, higher irradiance, comparable efficacy
  • Transepithelial (epi-on): the epithelium is preserved, less painful, more moderate efficacy — a useful option in children
Aftercare

Recovery

Marked discomfort for the first 2-3 days (epi-off protocol). The epithelium heals in 5 to 7 days, while vision is still blurred. Gradual recovery over 1 to 3 months.

Contraindications

Good to know

Cornea too thin (endothelial risk), history of ocular herpes, pregnancy.

Risks

Risks to be aware of

Infectious keratitis, rare but serious, during healing (close follow-up). Transient corneal haze that usually resolves. Stabilization may fail; retreatment can be considered.

Efficacy

Clinical data

Stabilization reported in about 90% of patients at 5 years. The KERALINK trial, 2021 (Larkin, Ophthalmology), confirmed its efficacy in children and adolescents.

At the practice — how I work

I perform cross-linking in the operating room, with a protocol tailored to each profile (classic Dresden or an accelerated variant depending on pachymetry and age). Follow-up is systematic at day 1, day 7, month 1, month 3, month 6 and month 12, with a topographic check on the Anterion to confirm stabilization.

Surgical option

Intracorneal ring segments (ICRS) — regularizing the cornea

An alternative or complement to cross-linking when regularizing the corneal surface is desirable.

What is an intracorneal ring segment?

An intracorneal ring segment is a small implant made of a biocompatible polymer (PMMA), inserted into the corneal stroma through a tunnel created with a femtosecond laser. Several models exist, including:

  • KeraRing (Mediphacos): PMMA arc segments, available in several thicknesses and arc lengths
  • Intacs (Addition Technology): semicircular PMMA segments, the original model
  • Ferrara Ring: PMMA arc segments with a triangular profile
  • MyoRing: closed circular ring, with a specific profile and indications

Mechanism

The ring segment causes central flattening and regularization of the corneal surface. Irregular astigmatism decreases, which can improve visual acuity and contact lens tolerance. This effect is reversible: the segment can be removed if necessary.

Indications in keratoconus

  • Moderate KC (stage I-II) with contact lens intolerance
  • In addition to CXL: the ICRS + CXL combination is often offered to stabilize the cornea biologically and regularize it optically
  • When an improvement in corrected acuity is desirable
  • An alternative for patients who decline transplantation or for whom it is contraindicated

Technique

A circular intrastromal tunnel is created with the femtosecond laser, deep in the stroma, and one or two segments are inserted into it depending on the corneal profile. Outpatient procedure under topical (eye drop) anesthesia.

Advantages

  • Reversibility (the segments can be removed)
  • Possible improvement in corrected acuity and contact lens tolerance
  • Short outpatient procedure
  • Recovery is usually straightforward

Limitations and risks to be aware of

  • Limited effect in very advanced forms (stage IV)
  • Requires sufficient corneal thickness in the implantation zone
  • Possible halos and double vision at night (optical effect of the segment)
  • Possible decentration or migration of the segment
  • Extrusion of the segment (rare)
  • Low risk of intrastromal inflammation or infection
  • Coverage: intracorneal ring segments implanted for keratoconus are specifically covered by the French national health insurance (Assurance Maladie) when the indication is approved (LPP list of reimbursable products). Your complementary health insurance (mutuelle) may cover the balance depending on your policy.

Recovery

Functional vision from day 2-3, complete stabilization over 3 to 6 months. Follow-up at day 1, day 7, month 1, month 3 and month 6.

Combined strategy: CXL + ICRS is often the best approach for stages II-III: CXL stabilizes biologically, ICRS improves optically.

Optical correction

Specialty contact lenses — restoring functional vision

When glasses fail, specialty contact lenses provide optimal correction of keratoconus.

RGP lenses

Rigid gas permeable

They create a regular refractive surface over the irregular cornea and correct irregular astigmatism far better than glasses. Comfort requires an adaptation period; high-permeability materials improve tolerance.

Hybrid lenses

Rigid center, soft skirt

A rigid center (to correct astigmatism) and a soft periphery (for comfort). A useful intermediate option for patients who cannot tolerate pure RGP lenses, before a possible switch to scleral lenses.

Scleral lenses

Resting on the sclera

These lenses rest on the sclera and not on the cornea. The cornea is bathed in a tear reservoir — a true “liquid bandage.” Comfort and quality of vision are often excellent, even in advanced keratoconus.

A study I contributed to — scleral vs RGP lenses

Knoeri J, Mhenni R, Friquet C, Hage A, Cuyaubère R, Borderie M, Leveziel L, Bouheraoua N, Borderie V. Comparison of optical aberrations in keratoconus with scleral versus rigid gas permeable lenses. Eur J Ophthalmol. 2024;34(2):394-398. DOI ↗ PubMed ↗

Finding: Scleral lenses correct higher-order optical aberrations (irregular astigmatism, coma, trefoil) significantly better than conventional RGP lenses. In advanced keratoconus, they are often the optical option of choice.

Risks and limitations to be aware of

Contact lens fitting at the practice

At the OPHTALIFE practice, I offer personalized fitting of contact lenses (RGP, hybrid, scleral). Fitting follow-up: day 3, month 1, month 3, then yearly.

Last resort

Corneal transplant — when is it necessary?

Today, fewer than 10% of patients with keratoconus need a transplant, thanks to modern therapeutic advances.

Indications

  • Very advanced stage IV KC: central opacification, severely compromised vision despite CXL, ICRS and scleral lenses
  • Chronic hydrops: residual rupture of Descemet's membrane with scarring
  • Severe corneal scarring after acute hydrops or an infectious complication
  • Persistent contact lens intolerance despite all fitting attempts
  • Associated chronic endothelial decompensation

Transplant techniques

DALK (Deep Anterior Lamellar Keratoplasty) is the technique of choice for pure keratoconus. It preserves the patient's own endothelium, which eliminates the specific risk of endothelial rejection and promotes long graft survival (often more than 20 years in published series).

Penetrating keratoplasty (PK): a full-thickness corneal transplant, indicated when the patient's own endothelium is also damaged (chronic decompensation, after-effects of severe hydrops). The cumulative risk of endothelial rejection is estimated at 10 to 20% at 5 years, depending on the series.

Prognosis, recovery and risks to be aware of

  • Gradual visual recovery over 6 to 12 months, sometimes longer
  • Corneal sutures usually removed at around 12 months
  • Sometimes significant post-transplant astigmatism, to be corrected later (glasses, contact lenses, more rarely surgery)
  • Risk of intraoperative conversion from DALK to PK if Descemet's membrane is perforated
  • Lifelong follow-up: monitoring for infection, rejection and endothelial decompensation
  • In pure keratoconus, DALK remains the option of choice when it is technically feasible

When should you be assessed for a transplant?

If any of the indications above apply to you, see a specialist promptly. A detailed assessment (specular microscopy / endothelial cell count, OCT, biomechanics) is needed before any decision.

Useful link: To learn more about corneal transplantation, see the dedicated page Corneal transplant.

At the practice

I personally perform corneal transplants (DMEK, DALK, penetrating keratoplasty) and manage the entire care pathway: indication, pre-operative assessment, surgery in the operating room and long-term post-operative follow-up. See the dedicated page Corneal transplant.

Have you been diagnosed with keratoconus?

I offer comprehensive, personalized care — from detailed diagnosis to current treatments (CXL, intracorneal ring segments, scleral lenses, DALK transplant if needed).

Essentials

Prevention and education — essential

Slowing and stabilizing keratoconus starts, above all, with simple habits and good eye hygiene.

Stop rubbing your eyes

This is the single most important step. I teach you attention-diversion techniques: instead of rubbing, gently press on your closed eyelids, lightly massage the area around the eyes, or apply a cold damp cloth. Educating patients on this point genuinely changes the course of keratoconus.

Treat eye allergy

Topical antihistamines (cromoglycate, alcaftadine), topical corticosteroids during flare-ups, and as background therapy: cyclosporine 0.05% for immune modulation. See my page Eye allergies.

Treat dry eye

Artificial tears, eyelid hygiene (warm compresses, meibomian gland care), sometimes IPL if there is associated meibomian gland dysfunction. See the page Dry eye disease.

Monitoring children

If you have keratoconus or there is a family atopic background, have your children screened from the age of 10-12. Early topography allows preventive action (treatment of allergy/dry eye, education) before symptoms appear.

Regular follow-up

Corneal topography every 6-12 months for stable forms, more often (every 3 months) if progression is rapid. This follow-up detects signs of progression and justifies starting CXL at the right time.

Key message: Combining prevention (stopping eye rubbing, treating allergy/dry eye) + early diagnosis (yearly topography) + proactive treatment (CXL as soon as KC is progressive) = the best prognosis and preservation of vision.

Your follow-up

Patient journey — 4 key steps

Here is how I support you from diagnosis through to stabilization.

1
Initial consultation & assessment
Detailed medical history, complete examination (acuity, refraction, slit lamp). Imaging on the Anterion, biomechanics (ORA, Corvis-ST). Diagnosis and classification. Explanation of the results and a personalized treatment plan.
2
Treatment — CXL ± ICRS ± Contact lenses
Depending on the stage and progression, I may offer: corneal cross-linking (stabilization), ICRS ring segments (optical improvement), fitting of specialty contact lenses (RGP, scleral). Immediate post-op follow-up: day 1, day 7, month 1, month 3, month 6, month 12.
3
Long-term follow-up & screening for associated conditions
Follow-up topography every 6-12 months. Confirmation of stabilization. Treatment and monitoring of associated allergy/dry eye. Screening of children if there is a family history. Adjustment of optical correction (contact lenses).
4
Transplant assessment (if needed)
If the disease is very advanced despite optimal treatment, assessment for a DALK transplant. Collaboration with specialized corneal surgery departments. Long-term post-transplant follow-up (5-10 years and beyond).
FAQ

Frequently asked questions

Next step

Monitor the progression of your keratoconus

Corneal topography, biomechanics, regular follow-up, cross-linking if progressive: a complete assessment allows me to make the diagnosis, stabilize the disease and plan the best strategy to preserve your vision.

Cabinet OPHTALIFE — Boulogne-Billancourt (92)
Former Assistant Specialist surgeon, Hôpital des Quinze-Vingts (Paris)
Book on Doctolib
Resources

Related pages

To learn more about topics related to keratoconus.

Eye allergies

Recognizing and treating eye allergy to slow keratoconus. Antihistamines, corticosteroids, cyclosporine.

Read the page ↗

Dry eye disease

Step-by-step treatment: artificial tears, IPL, cyclosporine, punctal plugs. Closely linked to keratoconus.

Read the page ↗

Corneal transplant

DALK and penetrating techniques, recovery, results. For very advanced forms of KC.

Read the page ↗

Dr HAGE's publications

Explore my research on eye rubbing, KC and dry eye in 3 key publications.

Read the page ↗
Bibliography

Scientific references

This page is based on international guidelines and reference publications in ophthalmology. All sources can be verified via their DOI or PubMed.

  1. 1

    Hage A, Knoeri J, Leveziel L, Majoulet A, Blanc J-V, Buffault J, Labbé A, Baudouin C. EYERUBBICS: The Eye Rubbing Cycle Study. J Clin Med. 2023;12(4):1529.

  2. 2

    Hage A, Knoeri J, Leveziel L, Majoulet A, Buffault J, Labbé A, Baudouin C. From ocular itching to eye rubbing: a review of the literature. J Fr Ophtalmol. 2023;46(2):173-184.

  3. 3

    Knoeri J, Mhenni R, Friquet C, Hage A, Cuyaubère R, Borderie M, Leveziel L, Bouheraoua N, Borderie V. Comparison of optical aberrations in keratoconus with scleral versus rigid gas permeable lenses. Eur J Ophthalmol. 2024;34(2):394-398.

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    Mas Tur V, MacGregor C, Jayaswal R, O'Brart D, Maycock N. A review of keratoconus: diagnosis, pathophysiology, and genetics. Surv Ophthalmol. 2017;62(6):770-783.

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    Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003;135(5):620-627.

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    Gomes JA, Tan D, Rapuano CJ, et al. Global consensus on keratoconus and ectatic diseases. Cornea. 2015;34(4):359-369.

  7. 7

    Larkin DFP, Lanzetta P, Buchdahl J, et al. Effect of corneal cross-linking versus standard care on keratoconus progression in young patients: the KERALINK randomized controlled trial. Ophthalmology. 2021;128(11):1516-1526.

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    Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283.

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    Leonardi A, Bogacka E, Fauquert JL, et al. Ocular allergy: recognizing and diagnosing hypersensitivity disorders of the ocular surface. Allergy. 2012;67(11):1327-1337.

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    Melles GR, Ong TS, Ververs B, van der Wees J. Descemet membrane endothelial keratoplasty (DMEK). Cornea. 2006;25(8):987-990.

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    Belin MW, Ambrósio R Jr. Scheimpflug imaging in keratoconus and ectatic disease. Curr Opin Ophthalmol. 2013;24(4):285-289.

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    Hashemi H, Heydarian S, Hooshmand E, et al. The prevalence and risk factors of keratoconus: a systematic review and meta-analysis. Cornea. 2020;39(2):263-270.

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    Godefrooij DA, de Wit GA, Uiterwaal CS, Imhof SM, Wisse RPL. Age-specific incidence and prevalence of keratoconus: a nationwide registration study. Am J Ophthalmol. 2017;175:169-172.

  14. 14

    Wittig-Silva C, Chan E, Islam FMA, Wu T, Whiting M, Snibson GR. A randomized, controlled trial of corneal collagen cross-linking in progressive keratoconus: three-year results. Ophthalmology. 2014;121(4):812-821.

  15. 15

    Amsler M. Le kératocône fruste et le kératocône classique : keratoconus classique et keratoconus fruste, arguments unitaires. Ophthalmologica. 1946;111:96-101. (Historical reference for the Amsler classification, later adapted by Krumeich et al.)

The content of this website is for information purposes only and is not a substitute for a medical consultation. Any treatment decision should be made together with your ophthalmologist.