Post-penetrating keratoplasty astigmatism

Postoperative astigmatism is one of the common complications affecting visual outcomes after a penetrating keratoplasty. It can result from various factors related to host, donor and surgical technique, resulting in suboptimal visual outcome. While some of the measures taken during preoperative planning and during actual surgery can reduce the magnitude of postoperative astigmatism, postoperative correction of astigmatism is often required in cases with high degrees of astigmatism. When spectacles and contact lenses fail to provide optimal visual outcomes, various surgical techniques that include astigmatic keratotomy, compression sutures, toric intraocular lens placement, and laser refractive procedures can be considered. When none of these techniques are able to achieve a desired result with in the acceptable optical range, a repeat keratoplasty is considered a last option. We discuss the various causes and management of complication of postoperative astigmatism occurring after a full thickness corneal transplantation surgery.

Optical pachymetry-guided custom excimer laser-assisted lamellar keratoplasty for the surgical treatment of keratoconus

PURPOSE

To evaluate the anatomic and functional results of optical pachymetry-guided custom excimer laser-assisted lamellar keratoplasty in keratoconus patients.

SETTING

Eye Clinic, University of L'Aquila, L'Aquila, Italy.

DESIGN

Prospective noncomparative case series.

METHODS

Patients with keratoconus having unilateral surgery using custom excimer laser-assisted lamellar keratoplasty were evaluated. A transepithelial excimer laser ablation was planned to leave an estimated uniform thickness residual stromal corneal bed of 200 μm. The donor lamella was prepared with the excimer laser and subsequently sutured to the host cornea using 16 single 10-0 nylon sutures. The eyes were examined preoperatively and 3, 6, 12, and 24 months postoperatively. Outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, computerized videokeratography, pachymetry, and endothelial specular microscopy.

RESULTS

Of the forty-three treated eyes, 35 were available at the 24-month follow-up visit, at which time the UDVA was better than 20/60 in 16 patients (45.7%) and the CDVA was 20/40 or better in 31 patients (88.6%). The mean refractive astigmatism was -2.11 diopters (D) (P<.05) and the mean spherical equivalent manifest refraction, -2.60 D (P<.05). No statistically significant changes in mean corneal endothelial cell density were observed postoperatively. In 1 case, the donor lamella was exchanged secondary to an altered reepithelialization process with initial corneal melting.

CONCLUSION

Two-year findings indicate that pachymetry-guided custom excimer laser-assisted lamellar keratoplasty is a useful surgical treatment for moderate to advanced keratoconus, preventing the need for the more invasive procedure of penetrating keratoplasty.