September 21, 2018
1 min read

Topography-guided ablation enhances PRK results in myopic eyes

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Topography-guided custom ablation treatment PRK showed good outcomes in eyes with low to moderate myopia.

Forty eyes of 25 patients with low to moderate myopia, with or without astigmatism, were included in a retrospective study. They underwent topography-guided custom ablation treatment (T-CAT) PRK with the Alcon WaveLight EX500 excimer laser platform. Patients had no previous ocular surgery, refractive stability for at least 1 year, corrected distance visual acuity (CDVA) of 20/25 or better, spherical equivalent refraction of less than 6 D, refractive astigmatism of less than 3 D, and age between 18 and 40 years.

Corneal topographies were obtained with the Allegro Topolyzer Vario system (Alcon), and collected data were analyzed by a specialist and then transferred to the PRK laser platform software. All patients were treated by the same surgeon.

Patients were examined at 1 day, 1 week, and 1, 3 and 6 months postoperatively.

Primary outcome measures included manifest refraction spherical equivalent (MRSE), uncorrected distance visual acuity (UDVA), CDVA, actual vs. targeted change in spherical equivalent and change in lines of vision.

At 6 months, MRSE, sphere and cylinder were significantly reduced. Mean MRSE was –0.03 D as compared with –2.61 D preop. Ninety-five percent of eyes were within ±0.5 D of intended correction. CDVA improved in 40% of eyes, and postoperative UDVA was the same as or better than preoperative CDVA in 97.5% of eyes.

Due to delayed epithelial healing, one eye presented loss of one line of CDVA at 6 months postoperatively. Ten patients reported transient symptoms related to dry eye, foreign body sensation and light sensitivity up to 3 weeks postop due to superficial punctate keratitis. Twenty-one patients experienced vision fluctuation during the first month.
No symptoms related to visual quality, such as glare, halos or starbursts, were reported. No cases of infections were diagnosed during the follow-up.

“Our results suggest that T-CAT PRK provides good outcomes and improves the visual performance,” the authors wrote. However, they recommended caution with this approach “because distinct algorithms have been described in the literature that may result in complications related to incorrect planning by the surgeon with no experience with customized ablation” – by Michela Cimberle

Disclosure: Faria-Correia reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.