Does Keratoconus Cause Blindness?

Keratoconus rarely leads to complete blindness, but if you leave it without treatment it can reach a point of very severe damage to vision, where the patient cannot walk, read or drive without help. This is the distinction I explain to my patients between "blindness" in the strict medical sense and "severe visual impairment", because this difference changes the way we deal with the anxiety a patient brings into the clinic.

Most of the people who ask me this question come after seeing a diagnosis of keratoconus, in themselves or in a family member, afraid that the story will end in a total loss of sight. The truth is that keratoconus is a progressive disease, meaning it develops gradually over years, and it does not involve a sudden loss of vision except in one exceptional situation that we will come to below. And as long as it is diagnosed early and we start the appropriate treatment, the likelihood of the story reaching a dangerous stage becomes very small.

What actually happens if the disease is left without treatment?

Keratoconus happens when the cornea (the transparent layer at the front of the eye) starts to thin and take on a cone shape instead of its regular spherical shape. This thinning does not stop on its own. If there is no medical intervention, it keeps getting worse in stages:

• Early stage: irregular astigmatism and mild blurring, usually corrected with glasses or ordinary contact lenses.
• Moderate stage: the astigmatism increases, glasses are no longer enough, and the patient needs specialist rigid contact lenses (RGP) in order to see well.
• Advanced stage: the cornea thins further and takes on a clearly cone-shaped profile, vision becomes blurred even with lenses, and scarring may appear on the cornea itself.
• Severe stage: very marked thinning with the possibility of a sudden internal tear in the cornea, which is what we call hydrops (acute corneal oedema).

What matters is that this deterioration is not necessarily inevitable. On our page about keratoconus we explain that early diagnosis stops the condition from deteriorating in a very large proportion of patients, and that is exactly why we focus on regular examination for anyone with a family history or early symptoms such as constant itching in the eyes, or changing their glasses more than once a year.

Hydrops (acute corneal oedema): the acute complication that really can threaten vision quickly

This is the exception I mentioned above. Acute hydrops happens when the inner layer of the cornea (Descemet's membrane) tears suddenly, so fluid from inside the eye enters the corneal tissue and causes sudden, severe swelling. The patient feels it as a sudden pain, redness and severe blurring that come on over hours, not weeks, and that is completely different from the usual gradual deterioration of the disease.

The good news is that most cases of hydrops improve on their own over weeks to months with supportive treatment (anti-inflammatory drops and concentrated saline to reduce the swelling), and after that we can assess the need for a surgical intervention such as a corneal transplant if a scar remains that affects vision. I have explained this condition in more detail, and how we deal with it step by step, in a separate article about acute hydrops. If you feel its symptoms suddenly, that is the moment when you need to call your clinic immediately, not wait for your ordinary appointment.

The treatment ladder that stops the disease before it reaches a dangerous stage

In our clinic we deal with keratoconus as a disease that we grade on a treatment ladder, not as a single decision taken once. Each rung of the ladder is determined by the stage of the disease:

1. Corneal collagen cross linking (CXL): the first line of defence

The main aim of CXL is not to improve vision, but to stop the disease from progressing altogether. The procedure relies on riboflavin drops (vitamin B2) together with ultraviolet light at a calculated dose, which strengthen the collagen bonds inside the corneal tissue. According to the data published on the corneal cross linking cost page, the procedure stops the condition from progressing in a proportion that reaches 95% of cases within 12 months, and in a proportion of patients (roughly 30-50%) there is also a slight partial improvement in vision within 6-12 months after the session, but this is not guaranteed in every case and results may vary from one patient to another.

CXL prices vary according to the protocol used (same source):

• Accelerated cross linking: from about 400 to 560 dollars (roughly 20,000-28,000 Egyptian pounds)
• The conventional protocol (Dresden): from 500 to 700 dollars (roughly 25,000-35,000 Egyptian pounds)
• Without removing the outer layer (Trans-Epi): from 600 to 800 dollars (roughly 30,000-40,000 Egyptian pounds)
• A CXL package together with ICRS rings: from 1,200 to 1,800 dollars (roughly 60,000-90,000 Egyptian pounds)

These prices include the riboflavin, the ultraviolet device, the surgeon's fee, the room and the local anaesthesia, and the first week's medication.

2. Intracorneal rings (ICRS / Intacs): for moderate cases

If vision has become hazy and the irregular astigmatism has a significant effect, but the disease is still at an early to moderate stage, we turn to ICRS rings. These rings are implanted inside the corneal tissue through a fine tunnel created with the femtosecond laser (without a blade), and they help to redistribute the irregular curvature of the cornea so that the quality of vision improves. According to the ICRS rings cost page, the price ranges between 600 and 1,200 dollars per eye (roughly 30,000-60,000 Egyptian pounds), the procedure takes 20 to 30 minutes per eye, and recovery takes about two weeks. These rings are often done alongside CXL in the same session or a following session, so that we combine stopping the progression with improving the vision.

3. Corneal transplant: the last resort if the damage has reached an advanced stage

If the cornea has thinned a great deal, or has scarring that affects vision and has not benefited enough from CXL or the rings, we come to the option of a corneal transplant. What matters is that this is never a first choice, it is the solution when the other rungs of the treatment ladder are no longer enough. According to the corneal transplant cost page, there are two main types for these cases: DALK (a partial transplant that preserves the healthy inner layer of the patient's own cornea) at a price of 2,500 to 3,000 dollars, and PKP (a full transplant) for late cases at a price of about 3,000 dollars, with a general price range of 2,500 to 4,500 dollars depending on the technique, including the donor tissue, the surgeon's fee, the anaesthesia and the operating room. A partial DALK transplant is preferred whenever possible, because it preserves part of the patient's own tissue and reduces the likelihood of the body rejecting the graft.

Signs you must take seriously and contact me about immediately

Not every decline in vision should worry you to the same degree, but there are certain signs that deserve an urgent phone call rather than an ordinary appointment:

• Sudden pain in the eye with severe blurring that increases over hours: possible acute hydrops.
• Sudden redness accompanied by severe sensitivity to light.
• A rapid, noticeable drop in vision over a few days, not over weeks.
• The usual contact lenses no longer being able to stabilise vision the way they used to, even though they were working well.

If you have not noticed symptoms like these, that is an indication that the disease is progressing at its natural speed, and the priority becomes booking a regular examination and following up with your doctor, not waiting until the symptoms get worse. I advise my patients to take the corneal assessment test if they are not under regular follow-up, so that we know early if there are early indicators we need to act on before they get worse.

Frequently asked questions

Can keratoconus cause complete blindness?

It is very rare. The vast majority of patients keep a useful degree of vision with the right treatment at the right time, even in the advanced cases that need a corneal transplant. Complete blindness only happens in cases of prolonged severe neglect over long years without any medical follow-up.

Does CXL bring back the vision that has been lost?

No, its main aim is to stop the deterioration, not to recover vision. A slight improvement in vision may occur in a proportion of cases, but it is not the main aim, and results may vary from one patient to another.

Does acute hydrops mean I will definitely need a corneal transplant?

Not necessarily. A large part of hydrops cases improve with supportive treatment without surgery, and the decision is taken after the swelling has settled and we see the size of the remaining scar, if there is one.

How do I know whether I am at an early stage or an advanced one?

This assessment needs corneal topography with a specialist doctor, not just an ordinary vision test. If you have a family history or early symptoms, get checked early instead of waiting.