A New Multifaceted Approach to the Holistic Management of Keratoconus

As a life-long, progressive disease, keratoconus exerts enduring stress on patients’ mental and emotional well-being. Even in those who achieve good visual acuity with gas permeable lenses, keratoconus has been shown to cause continued detrimental effects on patients’ mental health and quality of life.^1,2 Therefore, it is incumbent upon clinicians to consider new and more effective ways of managing patients with keratoconus.

A new cornerstone in managing keratoconus progression

With a condition that typically onsets in a younger population, the cumulative psychological influences that keratoconus generates should not be underestimated. Studies have shown higher rates of mental and emotional distress with keratoconus progression, steeper corneal curvature, and reduced vision.^1,2 Many patients with refractive error have the luxury of wearing spectacles to achieve good functional vision and can freely alternate between glasses and contact lenses. In contrast, those with keratoconus may feel handicapped by their relentless dependence on contact lenses to function, and often fear their loss of independence and the inability to perform at work.³ Moreover, a lifetime economic model has demonstrated substantial financial burdens for patients when corneal crosslinking (CXL) is not performed to arrest keratoconic progression.⁴ As such, early keratoconus diagnosis is becoming increasingly important in the initiation of CXL intervention as soon as disease progression is detected.

CXL

The clinical benefits of CXL have been widely demonstrated.^5-9 Because CXL is the only proven method to clinically arrest progressive keratoconus, a new management paradigm has emerged that recommends standard CXL as a first-line treatment.^7,10 After corneal stabilization, however, it remains important to consider the visual rehabilitative aspect of managing keratoconus, given its detrimental effects on activities of daily living. With increasing advances in surgical techniques, a multifaceted approach to visual restoration should be considered based on individual goals.

ALTERNATIVE APPROACHES to vision management

Gas Permeable Lenses

After halting keratoconic progression with CXL, gas permeable lenses still provide the best vision for the majority of patients. However, for patients who exhibit lower contact lens tolerance or those who need to comply with a more limited contact lens wear time, newer surgical techniques, such as intrastromal corneal ring segments (ICRSs) via allogenic graft, toric implantable collamer lenses (ICLs), and topography-guided photorefractive keratectomy (TG-PRK) may offer corrective capabilities in decreasing visual-related disturbances.¹¹ Studies have demonstrated an overall improvement in post-CXL visual function with these surgical interventions.^12-17

CAIRS

Although polymethyl methacrylate rings are still used as ICRSs, corneal allogenic intrastromal ring segments (CAIRS) have recently been used to enhance visual outcomes post-CXL.^12,17 CAIRS uses allogenic donor tissue cut into segments that are implanted within the stroma, resulting in corneal flattening and regularization. The primary treatment purpose is to improve spectacle-corrected and UCVA in patients with keratoconus. Unlike Intacs Corneal Implants (Addition Technology), CAIRS can be implanted more anteriorly within the stroma, which may produce higher potency in reducing anterior corneal irregularity (Figures 1 and 2).¹² Additionally, allogenic grafts have presumably reduced complication risks when compared with synthetic material. To date, there have been no reports of corneal melts, foreign body sensation, halo or glare effects, or allograft rejections.¹³

Toric ICLs

Toric ICLs have been shown to be a safe and effective management option for patients with stable keratoconus who report satisfactory refractive responses, especially those who have undergone prior CXL. In a study assessing 4-year outcomes in which toric ICLs were implanted after at least 1 year after epithelium-off (epi-off) CXL, UCVA was 20/40 or better in all patients, with 45% achieving 20/20 or better.¹⁴

ICLs are available in the United States for myopic prescriptions of -3.00 D to -20.00 D sphere with cylinder corrections between 1.00 D to 4.00 D and can be considered for patients with keratoconus who desire less dependence on their contact lenses. After CXL, ICL does not induce further changes in the anterior and posterior corneal surfaces, which may help with treatment predictability. In the same study, post-ICL manifest refraction showed > 97% eyes were within ± 1.00 D of the targeted correction.¹⁴

TG-PRK

TG-PRK can also be performed after CXL or simultaneously with CXL. One study suggested better visual outcomes with TG-PRK by waiting for refractive stability at least 3 months after CXL.¹⁵ Similar to CAIRS, the purpose of TG-PRK is to decrease the irregularity of the anterior corneal surface, reduce any higher-order aberrations that are present, and give patients with keratoconus improved refractive responses and/or the ability to better tolerate glasses after contact lens removal. Russo et al reported that most patients achieve an outcome of having a postoperative spherical equivalent within ± 1.00 D.¹⁶

PATIENT CASE

A 28-year-old male with keratoconus presented to the Midwestern University Eye Institute for a TG-PRK evaluation of each eye with complaints of poor, variable vision OU. He had already undergone epi-off CXL OU 3 years prior (Figure 2). Per the patient, given his difficulty inserting and removing scleral lenses and with lens fit and comfort with corneal gas permeable lenses, he was informed that corneal transplants might be the next best management option. His ultimate goal was to improve his vision enough to go through school. He reported a loss of ability to read, which he required to successfully complete his education.

The patient’s entering UCVA was 20/125 OD and 20/200 OS. After evaluation, it was determined that he was not a good candidate for TG-PRK, and alternative surgical options were reviewed with him. He elected to pursue CAIRS OD and toric ICL OS.

One month later, the patient was less satisfied with his vision OS, and CAIRS OS was subsequently recommended. Upon healing from the CAIRS and ICL procedures (Figure 3), his UCVA improved to 20/80+ OD and 20/40-2 OS, allowing him more functional vision without lens wear. Encouraged by the clinical results, he was open to being refit in scleral lenses to further refine his vision. He was first refit into a scleral lens OD 1 month after CAIRS implantation, which yielded BCVA of 20/20. With improved UCVA OU and BCVA OD, he is looking forward to a scleral lens refit OS at his next CAIRS follow-up appointment.

TAKE-HOME POINTS

Keratoconus significantly and negatively affects a patient’s mental health. Despite having better visual acuity, mental health scores have been found to be lower in patients with keratoconus compared with those with other chronic eye diseases, such as glaucoma and age-related macular degeneration.¹ These findings underscore the importance of detecting keratoconic progression early with prompt CXL intervention.

Undoubtedly, many patients with keratoconus achieve their most visually optimal results with specialty contact lenses, which typically can be resumed or refit at 1 month after FDA-approved epi-off CXL.¹⁸ Not to mention that ongoing advancements in specialty contact lenses, such as residual higher-order aberration corrections,¹⁹ will continue to elevate clinical successes in managing patients with stabilized keratoconus. However, it is worth noting that a combined approach of surgical techniques and specialty contact lenses may offer patients more visual freedom, better compliance with a healthier contact lens wearing schedule, and an improved quality of life. With this in mind, partner with a corneal specialist to help your patients with keratoconus obtain functional vision with and without contact lenses and allow them the freedom to choose the visual capacity they need to confidently manage all activities of daily living.