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Up Front | Sep 2001

Cataract Challenge

Keratoconus in a 71-Year-Old Male

CASE PRESENTATION
A 71-year-old black male had been experiencing decreased vision over the past few years and requested consultation for management. He inquired whether he was a candidate for laser vision correction. In 1997, he had 20/30 BSCVA. By January 2000, he had BSCVA of 20/40 OD and 20/25 OS with correction of -7.50 + 6.00 X 145 OD and -1.50 + 2.00 X 048 OS. Early cataracts were detected, and keratoconus was discovered upon topography.

The patient grew increasingly unhappy with his inability to see and tried a gas permeable contact lens fitting in an attempt to improve his vision, which unfortunately was unsuccessful.

By 2001, the patient reported nighttime glare, which limited his ability to drive; his eyesight was deteriorating, and he could not see well enough to recognize familiar faces. The patient now had 2+ nuclear sclerosis, dense cortical changes, and a posterior subcapsular cataract in the right eye. His BSCVA was 20/70 OD and 20/60 OS.

HOW WOULD YOU PROCEED?
1. What is the proper management of this case?
2. How much visual loss was attributable to cataracts versus keratoconus?
3. How reliable do you expect the A-scan to be?
4. What type of IOL should be inserted?

SURGICAL COURSE
I performed cataract surgery and implanted two STAAR toric lenses in this patient to alleviate the excessive astigmatism caused by the keratoconus. In the OD eye, four Sonomed A-scan measurements revealed four completely different outcomes due to irregular K readings. Toric IOLs required to approach emmetropia ranged from 13.5 + 3.5 up to 16.0 + 3.5. It was impossible to rely on any of the measurements, due to the extreme variations.

I decided to insert a 16.0 + 3.5 X 130 (based on reasonably consistent axis readings, the spherical component was the hypothesis). The Ks ranged from 43.37 @ 37 and 50.50 @ 131 OD; the axial length measurements ranged between 23.75 and 24.75. OS axial length was 23.81 with Ks of 43.62/178 and 46.12/88. An 18.5 + 3.5 D X 88 STARR toric IOL was inserted.

The patient's surgery was performed, and his vision on postoperative day 1 was 20/40 OD and 20/40 OS uncorrected. He is now able to read 20/30 without correction, and his postoperative refraction is -2.00 + 2.00 X 125 OD, correctable to 20/30-2 and -2.75 + 1.50 X 48, correctable to 20/25.

OUTCOME
The patient was ecstatic with the results, and sees very well both near and far without correction. I believe this toric lens technology will allow us to treat complex keratoconus patients without any ill effects on their corneas.

The patient's axis of astigmatism remained the same over the past 10 years, and even if the diopters of cylinder increase, he will still benefit greatly by having at least 2.5 D corrected by the IOL. In this case, the patient improved by more than 5.0 D, reducing his cylinder from >7.0 D to 2.0 D, an unexpected, but positive result.

Toric IOL technology is slowly gaining popularity, and if used correctly will be a great adjunct to all cataract and intraocular refractive technology. The lens is always oriented along the steep axis of astigmatism, that is, the highest number using the plus cylinder. It is never based on the refraction of the patient as the lens can contribute to that number, skewing the effect of correcting corneal astigmatism only. It is difficult to ascertain exactly how we eliminated 5.0 D of astigmatism in this patient's right eye; however, the crystalline lens must have contributed to his extreme astigmatism. I have found this to be true in cataract and refractive patients using this technology, but I am truly overwhelmed by these results in a keratoconus patient. n

Sheri L. Rowen, MD, is an Assistant Clinical Professor at the University of Maryland, Baltimore, Maryland, Director of the Eye & Cosmetic Surgery Center at Mercy Medical Center, Baltimore, Maryland, and Director of Rowen Laser Vision & Cosmetic Center, Towson, Maryland. Dr. Rowen has no financial interest in any companies mentioned within this case study. (410) 332-9500; srowdance@aol.com
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