Suspect keratoconus on topography

[Whiteshepherd]

I was curious if any of you guys know if the ete has keratoconus if the topography machine says "suspect keratoconus" at the top of the topography? My lasik doc's machine said "suspect keratconus" on the topographies for a couple of years prior to diagnosis. I am wondering if they actually knew something was amiss and didn't tell me. Just curious if you guys have any knowledge.

Brad

[Andrew MacLean]

Brad

Good question, I'm sure that there will be somebody along in a moment with an answer.

Andrew

[Lynn White]

Hi there

Topography machines usually have a mathematical formula (algorithm) by which the degree of keratoconus is calculated. Information, such as differences in the rate of curvature of the curvature above and below the midline, is gathered and used to calculate the probability of KC. Occasionally, some KC eyes come out as normal and vice versa but I would always personally take notice of such a read out and discuss it with the patient.

If a machine falsely identifies a cornea as keratoconic, this is called a false positive but you do have to make sure you have other data to call on to be sure the suggestion is indeed false. Obviously, in your case, it was an accurate detection.

Lynn

[Whiteshepherd]

Hi there

Topography machines usually have a mathematical formula (algorithm) by which the degree of keratoconus is calculated. Information, such as differences in the rate of curvature of the curvature above and below the midline, is gathered and used to calculate the probability of KC. Occasionally, some KC eyes come out as normal and vice versa but I would always personally take notice of such a read out and discuss it with the patient.

If a machine falsely identifies a cornea as keratoconic, this is called a false positive but you do have to make sure you have other data to call on to be sure the suggestion is indeed false. Obviously, in your case, it was an accurate detection.

Lynn

Hi Lynn,

So in other words it is probable that my lasik surgeon saw the aberrations of the cornea on the slit lamp evaluations when the topography machine said, "Suspect keratoconus"?

In your experiences which lenses work best for a smaller but further protruding ectasia on the lower portion of the eye? Just curious as to what you suggest. My left eye protrudes more and is giving me a fit and the right eye has a larger ectasia but does not protrude as much. The standard rgp works pretty well on the right eye and I have tried the Synergeyes Clearkone on the left eye but I can't get it out so I am returning the lens. Thanks

Brad

[Lynn White]

HI Brad,

Slit lamp shows up visible changes (with a certain amount of magnifcation) within the cornea. If you are "suspect keratoconus" it is unlikely that anything would show up on slit lamp. If it did, that would confirm keratoconus and it would no longer be suspect.

No-one can suggest what to fit on any particular cornea without a proper assessment. This is partly because keratoconic eyes are fairly unique to each individual but mainly because it would be unprofessional to attempt to predict what would work for you without seeing you!

I personally begin, for most cases that are mild to moderate, by looking at soft lenses, starting with disposables and working my way up through lathe cut torics to specialist soft lenses such as KeraSoft. Then if none of these work, I go to rigid lens types. The reason for this is many fold, not least that soft lenses are easier to tolerate and work better in dusty environments.Also, its far easier to fit from soft to RGP than the other way around, as RGPs tend to change the shape of the cornea slightly and this has to "wash out" before the cornea is stable for a soft lens fitting.

Soft lenses do work a good deal more often than people think - I saw a patient not long ago who had worn RGPs for KC in both eyes for 10 years and had real trouble all that time with the lens in the right eye. When I examined him, the right eye was virtually normal and could see 6/5 in glasses! He now wears a disposable soft in that eye and is much more comfortable.

Spectacles and normal soft lenses should always be considered first before dismissing them as an option. After that, whichever lens works best in terms of vision and wearability is the lens that is best for you.Only a proper examination can determine that.

Lynn