# Femtosecond laser-assisted half top hat penetrating keratoplasty for keratoglobus

## TL;DR

A new corneal transplant technique using a femtosecond laser improves vision and strengthens the cornea in patients with keratoglobus.

## Contribution

A modified donor-only top hat keratoplasty technique using femtosecond laser for keratoglobus is introduced.

## Key findings

- Best corrected visual acuity improved significantly in both patients post-surgery.
- Keratometry values decreased and peripheral corneal thickness increased in both cases.
- No complications were observed during the 12–24 month follow-up period.

## Abstract

To describe a modified technique utilizing femtosecond laser-assisted penetrating keratoplasty for the surgical management of keratoglobus with an extremely thin peripheral cornea.

Two eyes of two patients with advanced keratoglobus underwent a modified, donor-only, top hat keratoplasty. Femtosecond laser-assisted top hat configuration was exclusively performed on the donor cornea (half top hat) and sutured under the recipient's cornea which underwent a regular full thickness trephination. Patients were followed up for 12–24 months after intervention. Visual acuity and anatomical results (measured using corneal tomography and anterior segment OCT) were evaluated after this intervention.

Post-operatively, best corrected visual acuity improved from counting fingers in the first patient and 20/720 in the second to 20/30 in both. Keratometry values markedly decreased, and peripheral thickness was augmented in both cases. No complications during the follow-up period were noted.

Top hat configuration keratoplasty on donor cornea alone may be a unique surgical solution enabling the augmentation of the peripheral cornea in keratoglobus eyes, providing good visual outcomes as well as structural integrity.

•Corneal transplantation in advanced keratoglobus remains a surgical challenge.•Donor only top hat keratoplasty– effective in keratoglobus with good visual outcomes.•Donor only top hat configuration - can be applied in other ectatic corneal settings.

Corneal transplantation in advanced keratoglobus remains a surgical challenge.

Donor only top hat keratoplasty– effective in keratoglobus with good visual outcomes.

Donor only top hat configuration - can be applied in other ectatic corneal settings.