Intraocular Lens Selection in Irregular Corneas

Educational Objectives

The goal of this program is to improve selection of intraocular lenses for patients with irregular corneas. After hearing and assimilating this program, the clinician will be better able to:

1. Select the most appropriate intraocular lens for a patient based on the type and treatability of the corneal irregularity.
2. Manage treatable corneal irregularities to optimize outcomes after cataract surgery.

Summary

Global consensus on corneal irregularity (2020): slit lamp examination is insufficient to determine presence of an irregularity; corneal topography or tomography is recommended as a point of care for all patients prior to cataract surgery; monofocal intraocular lenses (IOLs) are optimal for patients with irregular corneas, although small-aperture IOLs are approved and are a potential option

Evaluation: lift the upper eyelid to visualize the superior cornea and look for Salzmann nodules (these can often be removed with a superficial keratectomy); evaluate topography to identify subtle corneal irregularities; superficial corneal pathology can lead to irregular astigmatism that may be reversible with an in-office procedure; wait 4 to 8 wk to ensure the topography has stabilized before selecting the IOL and planning cataract surgery; look at the location of the epithelial basement membrane dystrophy (EBMD) irregularities before planning surgery; cataract surgery can be performed if the irregularities are mild, but diffractive optic technology should be avoided because the corneas can shift; if the irregularities are on the central cornea and easily visible on topography, consider superficial keratectomy, placement of self-retaining amniotic membrane, or bandage contact lens, and select the IOL after the topography has stabilized

Keratoconus: toric IOL may yield good outcomes if the astigmatism was treated with spectacles with good-quality vision; patients previously in a rigid gas-permeable lens with central irregularities that are poorly corrected with manifest refraction of the cylinder are unlikely to have good outcomes with a toric IOL

History of radial keratotomy (RK): topography often shows severe irregularities; manifest, topographic, and IOL biometry cylinders are often irregular, and determining the true degree of astigmatism is difficult; patients may have diurnal variation in vision; cataract surgery can further change the biomechanics of the cornea; scleral tunnel may be preferred, particularly if there are >8 RK cuts; placement of sutures may be necessary if old incisions splay open during cataract surgery; refractive stability is difficult to obtain; patient education is important; refraction immediately after surgery may not be maintained 3 mo later, and patients are likely to still need glasses after surgery; small-aperture (AcuFocus IC-8) IOL is a pinhole optic that increases depth of focus; studies showed a large degree of refractive and astigmatism (≤1.5 D) forgiveness

History of laser-assisted in situ keratomileusis (LASIK) and dry eye disease: Trattler et al (2017) found that 60% of patients who presented for cataract surgery were asymptomatic, although 50% had central corneal staining; Gupta et al (2018) found that 80% of patients who presented for preoperative cataract evaluation had ocular surface disease with abnormal tear osmolarity and levels of matrix metalloproteinase-9; patients with dry eye disease may not have symptoms but have fluorescein staining and rapid tear break-up time, which results in irregular corneas, errors in preoperative measurements, and development of symptoms postoperatively; American Society of Cataract and Refractive Surgery Clinical Committee Algorithm recommends aggressive treatment in the preoperative setting, including topical treatment of inflammation, management of meibomian gland disease, and healing of punctate keratitis on the surface of the cornea; perform repeat topography to look for stabilization prior to surgery; light-adjustable IOL is preferred because it is the only one in which outcomes can be guaranteed (corneal powers are unpredictable with other lenses)

Decision tree: for patients with treatable abnormal corneas (eg, pterygium, EBMD, Salzmann nodule), treat the abnormality and perform a follow-up topography; use the IOL of choice if the cornea is normal; if the irregularity persists, consider small-aperture, light-adjustable, or monofocal IOL; for nontreatable abnormalities (eg, keratectasia, keratoconus), consider collagen cross-linking if condition appears to be progressive or unstable

Readings

Dick HB, Gerste RD. Future intraocular lens technologies. Ophthalmology. 2021;128(11):e206-e213. doi:10.1016/j.ophtha.2020.12.025; Franco F, Branchetti M, Vicchio L, et al. Implantation of a small aperture intraocular lens in eyes with irregular corneas and higher order aberrations. J Ophthalmic Vis Res. 2022;17(3):317-323. Published 2022 Aug 15. doi:10.18502/jovr.v17i3.11568; Gupta PK, Drinkwater OJ, VanDusen KW, Brissette AR, Starr CE. Prevalence of ocular surface dysfunction in patients presenting for cataract surgery evaluation. J Cataract Refract Surg. 2018;44(9):1090-1096. doi:10.1016/j.jcrs.2018.06.026; Starr CE, Gupta PK, Farid M, et al. An algorithm for the preoperative diagnosis and treatment of ocular surface disorders. J Cataract Refract Surg. 2019;45(5):669-684. doi:10.1016/j.jcrs.2019.03.023; Trattler WB, Majmudar PA, Donnenfeld ED, McDonald MB, Stonecipher KG, Goldberg DF. The Prospective Health Assessment of Cataract Patients' Ocular Surface (PHACO) study: the effect of dry eye. Clin Ophthalmol. 2017;11:1423-1430. Published 2017 Aug 7. doi:10.2147/OPTH.S120159.

Disclosures

For this program, the following relevant financial relationships were disclosed and mitigated to ensure that no commercial bias has been inserted into this content: Dr. Farid is a consultant for Alcon, Alderya, Allergan, Bausch and Lomb, Bio-Tissue, CorneaGen, Dompe, Johnson & Johnson Vision, Kala, Novartis, Orasis, Sun Ophthalmics, Tarsus, and Zeiss. Members of the planning committee reported nothing relevant to disclose.

Acknowledgements

Dr. Farid was recorded at the 90th Midwinter Conference: Ophthalmology, held on January 7, 2023, in Universal City, CA, and presented by the Research Study Club of Los Angeles. For information on future CME activities from this sponsor, please visit https://researchstudyclub.org/2023-Program. Audio Digest thanks the speakers and Research Study Club of Los Angeles for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0.50 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0.50 CE contact hours.

Lecture ID:

OP611001

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.