Keratoconus: Optical and Surgical Management: Management of Post-Keratoplasty Astigmatism Publisher



Raeisi S¹ ; Bejandi ZB¹ ; Mohammadi SF² Show Affiliations
Source: Keratoconus: Optical and Surgical Management Published:2024

Abstract

Grafted corneas have high refractive mismatches with the recipient biometry and generally severe shape distortions. Every refractive correction which we use for virgin eyes have been used for grafted eyes as well, and we review them in the chapte. Contact lenses are used in high degrees of irregular astigmatism and aberrations that are not fully correctable and/or tolerable by spectacles. Astigmatic keratotomy (AK) is 1 or 2 corneal incisions on the steepest meridian of astigmatism and is used to correct high astigmatism not corrected by spectacles or contact lenses. Compression sutures mean placing tight sutures on the flat axis, it may help reduce astigmatism after keratoplasty. They are reversible and easy choices. Nylon 10.0 is usually used for these procedures. A combination of AK on the steep axis and placing compression sutures on the axis 90° away from it has been useful. Indications for excimer laser refractive surgery are anisometropia and contact lens intolerance, and it is considered 3–6 months after complete suture removal, a minimum pachymetry of more than 500μ and simulated keratometry values between 38D and 55D. Lenticule extraction within the graft button is a potential advantage over the LASIK flap because the flap is more likely to breach and weaken the graft host junction scar. Studies recommend that intrastromal corneal ring segment implantation after PKP must be performed a minimum of 1 year after PKP and a minimum of 3 months after complete suture removal. We can use toric intraocular lens during cataract surgery or clear lens extraction after keratoplasty following suture removal with regular astigmatism and minimal HOA. Repeat keratoplasty is recommended when all other interventions have failed to treat high or irregular astigmatism. © 2025 selection and editorial matter, Mehrdad Mohammadpour and Masoud Khorrami-Nejad; individual chapters, the contributors.