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Cataract and Fuchs’

Many factors determine if surgery will be combined or sequential

Cheryl Guttman Krader

Posted: Friday, December 7, 2018

A slit-lamp image of a patient with Fuchs’ dystrophy

When patients with Fuchs’ dystrophy develop cataract, surgeons are faced with deciding whether to operate on the cataract, the cornea or both and in what order if they choose to stage the procedures.

Discussing these questions at the 36th Congress of the ESCRS in Vienna, Austria, Jesper Hjortdal MD, PhD, and Donald Tan MD agreed that there are no one-size-fits-all answers. Both surgeons said that they generally do a triple procedure because then patients need only one surgery and benefit with a faster visual recovery. However, the decision is multifactorial.

“We need to take into account patients’ rising expectations for visual quality along with the rapidly changing field of corneal transplantation. Surgeon experience and the learning curve of Descemet membrane endothelial keratoplasty (DMEK) remains a major factor in the process of deciding whether to stage or combine the surgeries. When in doubt, the safest approach is always defensible. Although there are advantages of a combined procedure, it is probably often safer to do the surgeries sequentially,” said Dr Tan, Adjunct Professor, Singapore National Eye Centre, Singapore.

KEY QUESTION
Whether the patient’s visual symptoms are related to the corneal disease and/or the cataract is a primary consideration for surgical planning. Whereas blurred vision is a symptom of both cataract and Fuchs’ dystrophy, diurnal fluctuation is a sign of early corneal decompensation from Fuchs’ dystrophy.

“Patients with significant Fuchs’ dystrophy will notice difficulty in the morning and improvement later in the day,” said Dr Hjortdal, Clinical Professor of Ophthalmology, Aarhus University Hospital, Aarhus, Denmark.

Other features to look for when assessing the severity of the corneal disease include the presence of bullae, which is seen on slit lamp examination and associated with intermittent pain, poor low contrast visual acuity and increased corneal thickness.

Dr Hjortdal noted that in a study including 89 patients with grade 2 or worse Fuchs’ dystrophy and needing cataract surgery, only 35 patients went on to endothelial keratoplasty (EK) after cataract surgery. The only factors that predicted need for EK were epithelial valley determined by confocal microscopy and central cornea thickness (CCT). A CCT cut-off of 611 microns had 80% specificity and 63% sensitivity for predicting later EK surgery.

Dr Tan outlined indications for choosing among the surgical options that considered the various clinical scenarios that are encountered along the spectrum of coexisting cataract and Fuchs’ dystrophy and the advantages and disadvantages of the various surgical options.

He said that cataract surgery alone may be done for an older patient with significant cataract who may be less visually demanding and has minimal corneal changes. At the other end of the spectrum are patients who might be younger who have minimal lens opacity with significant corneal disease and higher visual expectations. Starting by performing EK only in these patients is a good choice because it is easier and will preserve accommodation.

In patients with significant cataract and endothelial disease, a less experienced transplant surgeon may choose to do the cataract surgery first because with a stable IOL complex, EK done as a second procedure will be easier. However, the EK procedure may best be done first if there is severe corneal oedema limiting visualisation for cataract surgery.

“The latest approach among cornea specialists is to do DMEK first and cataract surgery after the corneal curvature has stabilised because this approach gives better refractive accuracy and a better chance of achieving emmetropia,” Dr Tan said.

APPROACH FOR COMBINED SURGERY
Dr Hjortdal said that the triple procedure is usually straightforward. He performs conventional phacoemulsification, makes the capsulorhexis a little smaller to keep the IOL in place during the graft portion of the procedure and does not constrict the pupil. IOL power calculations must account for a hyperopic shift related to the graft procedure.

“In performing the IOL calculations, surgeons should aim for 1.25D more myopia when performing DSAEK and for 0.5-to-1.0D more myopia if doing DMEK,” Dr Hjortdal said.

Because EK does not affect spherical aberration, surgeons can choose an aspheric IOL that compensates for corneal spherical aberration.

Jesper Hjortdal: jesper.hjortdal@clin.au.dk
Donald Tan: donald.tan.t.h@singhealth.com.sg


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