Phakic lenses provide treatment option for keratoconus

Phakic lenses offer an option for treating some patients with keratoconus, according to Carmen J. Barraquer Coll, MD, professor and head of refractive surgery, Barraquer Institute of America, Bogota, Colombia.

The approach to treating keratoconus must be individualized, she stressed, adding that use of the lenses will not cure keratoconus but will improve visual acuity (VA) and "give [suitable patients] a better life."

Cases of primary keratoconus are classified as dystrophies and cannot be cured, Dr. Barraquer said. Cases of secondary keratoconus that are associated with trauma can be cured.

All cases of ectasia are associated with eye-rubbing, long-term use of contact lenses, and systemic pathology, she said.

"Patients [with keratoconus] come to me because they want to improve their visual acuity [VA]," Dr. Barraquer said.

Patients with ectasia may be treated by regularization of the corneal surface with contact lenses, intracorneal segments (rings), or corneal graft, or they may be treated by correction of the refractive defect with glasses or phakic lenses, to see whether the VA improves.

Dr. Barraquer and colleagues studied 82 eyes in which corneas were not suitable for lamellar refractive surgery. Posterior and anterior phakic lenses were used for high emmetropia, and intracorneal segments were used in cases of high astigmatism.

Patients' ectasia or keratoconus was no higher than grade 2.

A total of 82 eyes were treated with regularization using two kinds of corneal rings (Intacs, Addition Technology; Ferrara, Mediphacos). Forty-seven patients were available at 3 months' follow-up, 18 at 1 year, and none at 2 years.

At 3 months, keratography had changed 3 D. Astigmatism proved unpredictable. The dispersion graph of refractive change was not significant.

Best-corrected VA improved from 20/40 preoperatively to 20/30 postoperatively. A t-test Dr. Barraquer developed showed that VA tends to improve with time, she noted.

Phakic lenses were used in 56 cases. Forty cases were available at the 3-month follow-up, and 13 were available at 3 years.

VA without correction improved from 20/30 preoperatively to 20/25 postoperatively.

At 3 years, almost 50% of the patients had VA of 20/20 or better.

"The thing that is very interesting is that the corneas have remained stable," Dr. Barraquer said.

Corneal power increased slightly in two cases, she said; in all other cases, corneal power decreased.

"The only explanation can be that the patients have not rubbed their eyes after the surgery," she said.

Seventy-three percent of patients who received the phakic lenses had VA of 20/25, compared with 17% of patients who received the corneal rings.