Ophthalmic Physiol Opt. 2006 Mar;26(2):212.

Astin C.

Department of Optometry, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK.

Purpose: A number of patients who had undergone refractive surgery still required contact lens fitting. Indications for fitting included the correction of residual ametropia, anisometropia, and regular and irregular astigmatism. In some cases, a post-treatment therapeutic bandage soft contact lens was used to protect the treated eye and to promote regular epithelial healing. Lens fitting was reviewed to give recommendations for problem solving and fitting this category of patient.

Methods: Before lens fitting, a full history and symptoms and refraction were obtained. The practitioner explained the results of the refractive surgery, advised on advantages and limitations of lens wear and described the choices available. The fitting procedure involved anterior segment assessment and measurement of ocular parameters. Several steps were often required to achieve a successful lens fit and tolerance. Three main categories of refractive surgery were outlined: (1) Internal procedure, e.g. implantation of an intra-ocular lens or a special soft lens draped over the crystalline lens. (2) Corneal incision, e.g. penetrating and lamellar keratoplasty, radial keratotomy (RK), transverse incision for astigmatism reduction, and stromal lens insertion. (3) Laser techniques, e.g. PRK, LASIK, LASEK, Holmium laser and thermo-keratoplasty.

Results: Contact lenses were fitted aiming to cause least disturbance to the cornea which had already been compromised by previous surgery. Good oxygen transmission, surface wettability and lens design were important features. A rigid gas permeable (RGP) lens could support and protect the cornea, provide a corrective tear lens between the lens and the new corneal contour, and help to stabilise visual acuity. Often a RGP lens of large diameter was required to bridge over the contours of the central cornea region and assist lens centration. Good visual acuity was usually achieved unless residual stromal haze prohibited this. A soft lens draped over the cornea gave good comfort and lens centration. However, it was less effective on irregular astigmatism and led to variable visual acuity on RK or over wide laser ablation zones.

Conclusion: Fitting the post-refractive surgery cornea was challenging. Extra time and assessment were recommended as the new corneal topography could lead to problems with contact lens centration and stability of visual acuity. Waiting 3 months post-treatment to allow the corneal topography to stabilise before commencing fitting is particularly recommended for RK and PRK. Lens aftercare included management of the patients' high expectations.