Enlargement of the photorefractive keratectomy optical zone

F A Eggink, W H Beekhuis, S L Trokel, J M den Boon

    Research output: Contribution to journalArticleResearchpeer-review


    PURPOSE: To evaluate the safety and efficacy of a photorefractive keratectomy (PRK) re-treatment procedure that enlarges the optical zone and treats undercorrection.

    SETTING: Rotterdam Eye Hospital and Medisch Centrum Alkmaar, The Netherlands.

    METHODS: This study evaluated 16 eyes that had PRK for myopia with the Summit excimer laser that resulted in a mean undercorrection of -2.82 diopters (D). Patients also reported impaired night vision including difficulty in driving, halos, and stray light and ghost images. These phenomena persisted after spectacle correction of residual refractive error, necessitating further treatment with a larger ablation zone. With a VISX 20/20 excimer laser, the optical zone was enlarged to 6.0 mm and undercorrection treated with a 6.0 mm ablation.

    RESULTS: At 13.5 months after re-treatment, mean reduction in myopia was 1.70 D, resulting in a residual undercorrection of -1.08 D. In seven eyes, final refraction was within 1.00 D of emmetropia. Only two patients continued to report night-driving problems.

    CONCLUSIONS: Re-treating undercorrections combined with enlarging the ablation zone resulted in a reduction in myopia from a mean of 2.82 to 1.08 D. Subjective reports of halos and stray light images were decreased in all cases.

    Original languageEnglish
    Pages (from-to)1159-64
    Number of pages6
    JournalJournal of Cataract and Refractive Surgery
    Issue number9
    Publication statusPublished - Nov 1996


    • Adult
    • Cornea/physiology
    • Female
    • Glare
    • Humans
    • Image Processing, Computer-Assisted
    • Lasers, Excimer
    • Male
    • Myopia/physiopathology
    • Photorefractive Keratectomy
    • Refraction, Ocular
    • Reoperation
    • Safety
    • Treatment Outcome
    • Visual Acuity


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