Refractive surgery

Cataract surgery is one of these refractive procedures today, as the patient’s successful postoperative refractive surgery is the focus of attention. Here are additional rules that are not always easy to follow for the classic cataract surgeon! It is therefore helpful if the referring ophthalmologist, who usually knows the patient better, provides the surgeon with instructions that make the desired result possible. Not infrequently, patients are overwhelmed when asked about their desired refraction. Here, the phenomenon of the “agony of choice” occurs too often. In order to achieve the result that the patient expects from the operation with premium lenses, there are now numerous calculation formulas. However, these are only as good as the preoperatively determined data. And this is where the Pentacam® comes into play:

A 2 second measurement gives all the important information that helps to fulfill the desire of the patient (and also the doctor):

The ‘cataract pre-op’ panel shows:

■ The corneal anterior surface:

At a glance, a regular or irregular astigmatism is shown, for. B. to address a toric premium IOL. A sometimes unknown keratoconus would be z. An exclusion for a multifocal premium IOL. A possibly unrealistic expectation of the patient is to be relativized.

■ The corneal back surface:

If the front surface astigmatism is genuine, this is also evident on the back surface. Is the front surface design of the cornea z. B. contact lens induced = corneal warpage, this is reflected in an asymmetry of the back surface to the front surface. If one overlooks a contact lens-induced change, the desired refraction is usually clearly missed.

■ corneal thickness:

Is a very helpful information z. B. after a corneal refractive surgery such as PRK before z. B. 10 years, the patient has forgotten to specify, or in the state after a keratoplasty.

■ Scheimpflug:

Shows the anatomical findings whether phak, aphak, pseudophak or phakic IOL as well as the severity of the cataract. This is becoming increasingly important as private insurers often question the medical indication of cataract surgery. It is well known to payers that cataract surgery can also be “misused” as a refractive intervention. Then the question arises about the medical indication. This discussion can only be with facts such. B. the Schleimpflugdarstellung the cataract solve.

■ Table in the printout bottom left:

The simulated keratometer values with index 1.3775 use most of the IOL calculation formulas.

Helpful are the measured keratometer values from the center to 4 mm. This data is important if you have corneal refractive surgery and you want to use the Ray Tracing formula or an online IOL calculator. The Pentacam® offers in an additional program this Ray Tracing calculation on the same computer. The online calculator for calculating the IOL after refractive surgery is helpful. Often, however, the calculation spreads up to 5 dioptres. Ray tracing with Pentacam® measurements is far safer in our experience.

■ The spherical aberration of the cornea Z4.0:

Aspheric monofocal premium IOLs are the most commonly implanted in the world. The juvenile eye compensates the positive asphericity of the cornea with the negative asphericity of the lens so that most of the total asphericity of the optical system is balanced, that is equal to zero. If one balances the positive asphericity of the cornea with the appropriate negative asphericity of the IOL, one approaches the ideal state of the young eye. Consequence is z. B. increased contrast vision. The WFA Z40 is an important parameter whose importance is still underestimated. However, this value is significantly changed after corneal refractive surgery, so this is also an important clue.

■ Anterior chamber depth, corneal diameter, and pupil diameter provide additional helpful information, such as: For example, how well the pupil is expandable for surgery, how shallow the anterior chamber is, or whether nanoparticles may be present with a small corneal diameter.

■ And how reliable are these measured data? The table line QS = reliability of the measurement says so.

Since biometrics uses keratometer data almost at a factor of one, it is helpful not only to know the presentation of the measured data, but to see how it is distributed over the cornea and thus to be assessed realistically. If the measurement data is valid, then it makes sense to offer patients the individualized premium lens. If the patient does not want a premium lens, because the health insurance does not reimburse everything, then that’s his right. However, if you have not suggested or recommended the possibility of a premium lens to the patient, then as a doctor you have to put up with the reproach of the patient: “If I had known that there was a better lens, then I would have absolutely chosen it. … “or even more embarrassing:” my wife has paid 500 euros and a better one

Get a lens and I have no one offered! “For premium lens consulting has the Federal Association of German

Ophthalmic surgeons created a settlement proposal, which may be the basis for the profitability of a premium lens consultation with the Pentacam®.

After the surgical care z. B. with a toric premium lens is usually helpful to control or prove the correct fit of a toric intraocular lens. The objective and subjective refraction are crucial, but sometimes the refraction is not as intended. In case of a problem search, the Pentacam® can provide a very useful software function: the projection of the measured astigmatism together with the iris image (Bildl). If one additionally knows the operative axis planning, the precision of the operative lens implantation can be easily understood and shown to the patient

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