Surgical Planning and Technique
Although RLE is similar to cataract surgery, there are some additional considerations for planning and performing the procedure, as the primary surgical goal is refractive rather than restoration of vision lost due to cataract. In contrast to keratorefractive procedures, which are usually performed bilaterally in the same surgical session, RLE is usually performed as sequential surgery on separate days to minimize the potential for bilateral endophthalmitis. However, practices continue to evolve, and some surgeons are performing bilateral RLE in the same surgical session.
Preoperative corneal topography is essential to detect irregular astigmatism and to identify patients with corneal ectatic disorders, such as keratoconus and pellucid marginal degeneration. Patients with these conditions may still have RLE performed; however, they must understand the limits of vision correction obtainable and that the quality of vision may still suffer postoperatively from their irregular astigmatism. These patients must further understand that they are not good candidates for postoperative treatment with LASIK or photorefractive keratectomy to refine the refractive correction.
Surgeons must identify the degree of corneal versus lenticular astigmatism present, as only the corneal astigmatism will remain postoperatively. The patient should be informed if substantial astigmatism is expected to remain after surgery, and a plan should be devised to correct it in order to optimize the visual outcome. Small amounts of corneal astigmatism (<1.00 D) may be reduced if the incision is placed in the steep meridian.
Limbal relaxing incisions and arcuate keratotomies with either blade or femtosecond laser may be used to correct residual corneal astigmatism of less than 2.00 D (see Chapter 3). Supplemental surface ablation or LASIK could also be considered (see the following discussion on bioptics). Although glasses or contact lenses are an alternative for managing residual astigmatism, refractive surgery patients frequently reject this option.
Some surgeons obtain preoperative retinal OCT to identify potential macular pathology. Careful attention should be paid to the peripheral retinal examination, especially in patients with higher myopia. If relevant pathology is discovered, appropriate treatment or referral to a retina specialist is warranted. In patients with high axial myopia, retrobulbar injections should be performed with caution because of the risk of perforating the globe. Peribulbar, sub-Tenon, topical, and intracameral anesthesia are alternative options.
Most surgeons believe that an IOL should be implanted after RLE in a patient with high myopia rather than leaving the patient with aphakia, even when little or no optical power correction is required. Plano power IOLs are available if indicated. The IOL acts as a barrier to anterior prolapse of the vitreous, maintaining the integrity of the aqueous–vitreous barrier, in the event that Nd:YAG laser posterior capsulotomy is required. Some IOL models also reduce the rate of posterior capsule opacification.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.