As patients who have corneal inlays age, cataracts inevitably develop. Therefore, a discussion is needed on the preoperative evaluation, surgical technique, and postoperative management of these patients.
Preoperative Evaluation
The comprehensive preoperative assessment begins with a careful slit lamp exam and detailed corneal topography, identifying the inlay’s condition, location, and its effect on corneal curvature. These items must be performed, so both the patient and surgeon can decide whether it’s best to keep or remove the inlay prior to cataract surgery.
If the inlay is well tolerated in the patient’s eyes, the preference may be to keep it in place to help maintain depth of focus after their cataract surgery.
If there are signs of corneal haze, corneal thinning, or scarring, it may be best to remove the inlay prior to cataract surgery. This is because these problems could threaten the long-term health of the cornea, and affect the precision of IOL calculations needed for a successful surgical outcome.
Surgical Technique
The surgery technique choice is a nuanced decision. Traditional phacoemulsification is widely used due to its efficacy and safety profile. Additionally, femtosecond laser-assisted cataract surgery (FLACS) offers precision and safety. If there is an opaque corneal inlay, then femtosecond laser should not be used, as that may interfere with the laser delivery. Also, femtosecond lasers (cornea or lens based) are contraindicated in the presence of opaque corneal inlays. However, if a refractive or shape-changing inlay is present, femtosecond lasers may be considered.
Opaque inlays necessitate careful surgical planning to ensure the pupil is large enough to allow for visualization outside the inlay’s margins for cataract removal. Safe cataract surgery may be completed in situations of an opaque inlay being in place, but the patient and surgeon should be prepared that the inlay may need to be removed at the time of cataract surgery if the surgery cannot proceed safely secondary to visualization concerns.
IOL selection is an important consideration when corneal inlays are in place. Typically, in the presence of a corneal inlay, a monofocal IOL would be the logical choice due to the depth of focus provided by the inlay. However, should the inlay be removed, and assuming the cornea’s integrity and clarity is uncompromised, an extended depth-of-focus or multifocal IOL may be considered.
Opaque inlays typically don’t interfere with IOL power calculations; however, many patients with these inlays have undergone concurrent LASIK surgery, requiring surgeons to integrate this consideration into their calculations.
Targeting for a slight myopic outcome can enhance the inlay’s depth of focus performance, extending its benefits to a wider range of distances. In fact, it has been shown that aperture optics work best when the target is slightly myopic, as the defocus curve works both “to the left and right” of the refractive target, enabling it to sharpen both distance and near vision from an intermediate refraction.1
In a phakic patient with whom the patient had some accommodation, the target is typically around -0.75 D. In a pseudophakic patient with no accommodation, a target of -1.00 D to
-1.50 D may be preferable.
Postoperative Management
Postoperative management in corneal inlay patients is similar to traditional cataract surgery patients, though enhancement strategies may be necessary in corneal inlay patients, due to a high risk of missed target in pseudophakic eyes.
Additionally, enhancement strategies may be challenging in corneal inlay patients. This is because the inlay may be a contraindication to LASIK. Thus, enhancement strategies may require PRK or an
IOL exchange.
Regular follow-up based on clinical presentation is essential to detect and manage any long-term complications, such as corneal edema or haze secondary to long-term inlay biocompatibility issues, which could affect visual acuity. It is important that patients don’t get lost to follow-up when corneal inlays are present, as corneal inlays develop haze or scar tissue that could require explantation.2
Managing This Intersection
Cataract surgery in patients who have corneal inlays requires careful preoperative planning and intraoperative technique adaptation. Postoperative management must be vigilant and proactive. The intersection of cataract surgery and corneal inlays is a testament to the dynamic nature of ophthalmic medicine, demanding constant innovation and adaptability. CP
References
1. Kohnen T, Suryakumar R. Extended depth-of-focus technology in intraocular lenses. J Cataract Refract Surg. 2020;46(2):298-304.
2. Romito N, Basli E, Goemaere I, Borderie V, Laroche L, Bouheraoua N. Persistent corneal fibrosis after explantation of a small-aperture corneal inlay.
J Cataract Refract Surg. 2019;45(3):367-371.
