June 2015 Online Photo Diagnosis
BY LUCIANO BASTOS
This image shows dimple veiling in a keratoconic cornea with an intracorneal ring segment. The patient is a surgeon who underwent intracorneal ring implantation in his right eye about 15 years ago. Several years after the procedure, he experienced a spontaneous extrusion of the temporal segment. The patient is a very busy professional and, even though he is a medical doctor, he does not comply with our recommendations for follow-up visits. He only comes to the office every two or three years when he needs a replacement lens.
During biomicroscopy at the patient’s first visit in 2008, we noted inferior neovascularization, light corneal nebula where the temporal ring segment had been (Figure 2), and significant staining at the central and paracentral cornea OD. Also, there were calcium deposits along the nasal ring segment channel and an indentation induced by the patient’s current GP lens, which had been fit elsewhere (Figure 3).
Figure 2. Nebula, inferior corneal neovascularization, and the nasal ring segment.
Figure 3. Corneal indentation and scarring induced by a poorly designed and fit GP lens.
We normally would have discontinued lens wear for a few days to allow his cornea to return to baseline before refitting a new lens. However, despite our best efforts to convince the patient of this, he said it was not possible due to a full schedule of surgeries he needed to perform; he could not stop wearing lenses. We proceeded with refitting a new lens (Figure 4). The result was good. The patient continued to have success with this lens until recently.
Figure 4. Fitting achieved with an Ultracone PCR (Post-Corneal Ring) GP lens (Ultralentes).
In March 2015, the patient visited us and asked for new lenses. We again had the problem that the patient did not cooperate to achieve a better result—he was going on vacation in another country and could not even return to receive his lenses. Dr. Marcelo, MD, and I agreed to send the new lenses to the patient and to see him in one month.
At the same visit, the patient presented with the clear dimple veiling pattern seen in Figure 1. We did not have the time and the cooperation from the patient to determine how it had developed, so we indicated that we needed to perform anterior segment tomography as soon as he returned from his vacation.
We observed that he was wearing the lens fitted in 2012 and that his corneal topography had changed significantly—not progression, but more like a flattening effect in his superior paracentral cornea and an oblate but clearly irregular shape. It seemed clear that the nasal intracorneal ring segment was still tractioning part of the central cornea. The topography was more abnormal compared to seven years ago. This was probably due in part to some mild change in his condition, but mostly because he is not compliant with returning for follow-up care. In our experience, intracorneal ring implants only add more complexity to an existing irregular cornea, although we may be biased by the fact that we generally only see the unsuccessful cases.
As I stated in a previous column, sometimes we need to divert from our normal protocol to help a patient who urgently needs new lenses and simply cannot stop wearing his old ones. In this particular case, because the patient was a busy surgeon, he just could not afford to stop wearing his GPs. Desperate times sometimes require desperate measures, so we refit him with a steeper base curve Ultracone PCR GP lens design and instructed him to instill preservative-free artificial tear drops every two hours.
The new lenses were sent to the patient three days later, and he promised to return for a follow-up visit as soon as he returned from vacation. That was in March 2015, and we are still waiting for him.
Figure 5 shows the trial lens that we tested to achieve a better lens-to-cornea alignment. In the final lens, we reduced the overall diameter, flattened the central base curve, and steepened the secondary base curve. Hopefully, we did not flatten the central base curve too much; if the lens touches the inferior nasal portion of the cornea where the segment creates an anterior elevation, this would result in corneal erosion.
Figure 5. A rushed refit for a difficult case and patient.
I am sure that every practitioner has dealt with difficult patients such as this one. It is often frustrating, because we could achieve a better result if such patients would comply with our instructions. If we do not help these patients, they may end up with a poorly fitting lens from elsewhere that could cause more serious complications.
The presence of ring segments usually leads to a difficult GP lens fit; scleral lens fitting may be a healthy alternative, if possible.
Mr. Bastos is the director and clinical instructor of specialty contact lenses at the Instituto de Olhos Dr. Saul Bastos (IOSB), and is the director and specialty lens consultant of Ultralentes, a small laboratory specializing in GP and scleral lens designs in Porto Alegre, RS, Brazil.