A 41-year-old gentleman was referred to me by a corneal specialist in the United Kingdom for evaluation and management. His main complaint was increasing difficulty driving. He said it looked to him as though automobile headlights and streetlights formed a large tail coming down from the source and spilled onto the road. He provided a drawing of what he saw (Figure 1), and he said that he believed that his left eye was worse than the right.

The patient had radial keratotomy in his right eye 20 years earlier and reported better vision, however, he had starbursts and did not choose to have the left eye treated. He was managing with soft contact lenses in both eyes. A trial of hard contact lenses did not eliminate his visual symptoms.

At examination, his UCVA was 20/100 OD and 20/400 OS. His refraction in the right eye was -2.50 D, giving him an acuity of 20/15 and -4.50 -1.00 X 34 in the left, giving him an acuity of 20/25.

Slit-lamp evaluation revealed a superior abnormality of the cornea in both eyes, worse in the left. This consisted of mild thinning and vascularization with what appeared to be lipid deposition (Figure 2). Orbscan imaging (Bausch & Lomb, Rochester, NY) revealed mild elevation superiorly in both eyes (Figure 3) and central flattening from RK was evident in the right eye.

PRESENCE OF COMA
Zywave aberration maps (Bausch & Lomb) were obtained and confirmed the presence of coma. The point spread function image bore a strong resemblance to the image drawn by the patient. The predicted phoropter refraction was different from our refraction particularly in terms of axis and magnitude of cylindrical correction; this was also a concern. Central ultrasound pachymetry readings were 525 µm OD and 527 µm OS and superior pachymetry readings were 580 µm OD and 605 µm OS. The pupil sizes in mesopic conditions were 6 mm OD and 5.5 mm OS.

At this point, the gentleman was not able to drive and in danger of losing his job. He indicated he was desperate to have something done to improve his vision. What options were available? Neither spectacle correction nor soft or hard contact lenses eliminated his problem. Refractive errors were present in both eyes and were greater in the left. The Orbscan showed mild elevation and the abnormality did not really match the level of coma. Was the origin of coma the corneal pathology? As the anterior elevation map did not totally account for this, was there another source (eg, the posterior cornea)?

Because of the opacification, posterior corneal imaging using the Orbscan was not likely to be accurate. After much discussion, we decided to perform a wavefront treatment. The options were to perform LASEK or LASIK with IntraLase (IntraLase Corp, Irvine, California) with the hinge positioned superiorly. We felt that the use of a microkeratome might be hazardous, and the applanation and direct visualisation of flap creation using IntraLase were felt to be an advantage.

DETAILED COUNSELING
The patient was counseled in detail, and risks (including worsening of his condition) were outlined in no uncertain terms. We also felt that treating only one eye (the left eye) was the best initial way forward. The patient opted for Zyoptix Wavefront LASIK (Bausch & Lomb) with IntraLase to his left eye. This was performed with a 9.0-mm-diameter superior hinged flap and of 90-µm thickness. Iris recognition was accomplished successfully, and the treatment was uncomplicated.

On day 1 following surgery, his unaided visual acuity was 20/25 +2, and he reported a marked reduction in visual symptoms, although they were still present. At 1 month his acuity was 20/20 +2, and his symptoms were markedly reduced to almost no significance. His refraction was 0.00 -1.00 X 107, but there was no visual improvement. At 3 months, his acuity remained at 20/20 +2. At last follow-up (9 months) the acuity remained at 20/20, and refraction of 0.00 -0.75 X 90 improved acuity to 20/15.

Seven months following treatment of the left eye, the patient indicated that driving was better, however, the right eye visual aberration was still interfering with his ability to function properly. He requested surgery in the right eye and was happy to take the risk. We discussed the possible issues including problems that might occur with the flap as a result of previous RK. Treatment was performed, and a double raster pass was used this time with the 30-kHz IntraLase laser. The flap lift was straightforward, however, iris registration could not be obtained. Laser ablation was carried out using the eye tracker without recognition, and the flap was replaced without complication

On postop day 1, I was relieved to see the patient's UCVA at 20/30, though he complained of double vision. At 1 month, this improved to 20/25 and with a refraction of -0.25 D improved to 20/20. He reported that his symptoms were 90% better, and he was now able to drive.

SUMMARY
This gentleman had severe visual problems as a result of coma. We presume this was caused by superior corneal disease consistent clinically with Terrien's marginal degeneration. Fortunately, he did not have excessive thinning from the degeneration. Performing IntraLase LASIK with a superior hinge avoided the area involved, and ablation was confined to the normal cornea.

Zyoptix Wavefront (Zypotix Custom Wavefront LASIK system, Bausch & Lomb) correction resulted in a tremendous improvement in visual symptoms and refractive correction in the left eye in particular. Although the patient had RK in the right eye and iris registration did not work, he still had a good outcome. Hopefully, both eyes will continue to remain stable with no further progression of Terrien's marginal degeneration.

This case presented as a dilemma in terms of management. Ultimately, we were happy to proceed to a wavefront treatment on the basis that at worst the patient might still need contact lenses or spectacle correction. He was fortunate enough to benefit from both improved visual quality and elimination of the need for optical correction in both eyes.

Sheraz M. Daya, MD, FRCS(Ed), is director and consultant at the Centre for Sight, Corneoplastic Unit and Eye Bank, the Queen Victoria Hospital in East Grinstead, UK. He receives travel expenses from Bausch & Lomb and has received honoraria from IntraLase. Dr. Daya may be reached at sdaya@centreforsight.com or +44 1342 321 201.