Examination of the cornea includes an assessment of corneal thickness and whether corneal abnormalities, including edema, ectasia, guttae, or dystrophy, are present. Abnormalities could increase the risk of poor healing and decompensation postoperatively. Specular reflection with the slit lamp may provide an estimate of the endothelial cell count and information regarding cell morphology. Descemet membrane irregularity associated with cornea guttae, as well as any central opacity, may affect the surgeon’s view of the lens during surgery and limit visual acuity after surgery. In patients with pannus due to long-term contact lens use or other conditions, the surgeon can plan to avoid making corneal incisions in areas of vascularization, if possible. Also, weakened or thinned areas in the cornea can be identified so that they can be avoided intraoperatively.
The ocular surface is the first and principal refracting interface of the eye. Tear film quantity and quality are thus critical to visual results. Diagnosis and management of keratitis sicca, blepharitis, and epithelial basement membrane dystrophy are of critical importance in cataract patients, particularly if multifocal or toric IOLs are being considered.
If areas of scarring possibly consistent with a history of herpetic eye disease are present, prophylactic antiviral medication and careful monitoring of steroid therapy in the perioperative period may be advisable to prevent reactivation.
If the patient has undergone previous corneal refractive surgery, it is important to document the type of surgery and any associated corneal findings, including haze after photorefractive keratectomy (PRK), the location of a LASIK (laser in situ keratomileusis) flap, and the placement of radial or astigmatic incisions. It is also important to note any apparent problems with healing. If the patient has undergone previous radial keratotomy (RK), the surgeon must take care to develop a surgical plan that attempts to avoid corneal splitting at the site of the RK incisions. See also Chapters 7 and 12 in this volume and BCSC Section 13, Refractive Surgery.
Excerpted from BCSC 2020-2021 series: Section 11 - Lens and Cataract. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.