Traditional textbooks educate that the incidence of keratoconus is one per 2,000. That will equate to about 170,000 sufferers with keratoconus in the US.
Nevertheless, more moderen research counsel the incidence of keratoconus is a minimum of 10 occasions larger, or one per 200, equating to 1.17 million sufferers. We ophthalmologists know that keratoconus is a standard analysis in our practices, suggesting that the upper quantity is extra correct.
Keratoconus will be suspected with commonplace workplace tools together with retinoscopy, refraction and keratometry, however corneal topography and tomography are the usual for confirming the analysis, staging the situation and following up. Whereas controversy exists, I consider keratoconus is each genetic and environmental. A very powerful environmental danger issue is eye rubbing, and all sufferers with keratoconus or a household historical past of keratoconus ought to be recommended to keep away from eye rubbing.
The optical therapy of the progressive myopia and irregular astigmatism related to keratoconus is becoming with a contact lens, normally a specialty or scleral onerous contact lens. Whereas contact lenses can provide most sufferers improved imaginative and prescient, they don’t arrest illness development and in some circumstances could exacerbate it by long-term corneal contact. As soon as contact lens put on turns into inconceivable, sporting time turns into insufficient or ample imaginative and prescient can’t be achieved, keratoplasty is obtainable. Immediately, most U.S. surgeons make use of penetrating keratoplasty, however there are sturdy advocates for deep lamellar anterior keratoplasty, a tougher and time-consuming process. Keratoplasty is a significant enterprise for each the affected person with keratoconus and their surgeon, with lifetime high quality of imaginative and prescient and high quality of life points. For that reason, corneal surgeon innovators have sought different therapies for his or her sufferers with keratoconus for many years. Having participated on this quest for a greater therapy for keratoconus for five many years, I’ll share just a few private ideas. I disclose that I’ve participated as an organization board of director member, medical advisory board member, scientific investigator and/or investor in a dozen or extra firms innovating higher therapies for the affected person with keratoconus.
The choice therapies I’ll focus on embody thermal keratoplasty, corneal cross-linking, plastic and human tissue implants/lamellar keratoplasty, and excimer laser PRK.
Thermal keratoplasty was first proposed by Antonio Gasset, MD, within the mid-Seventies. I investigated his process and located its profit to be transient. I served on the board of administrators of Refractec and took part within the scientific trials that led to FDA approval of conductive keratoplasty for the short-term enchancment of hyperopia in 2002. I discovered CK to be a secure topical anesthesia outpatient therapy, and in choose circumstances, it was helpful in treating astigmatism together with that related to keratoconus. The problem was the profit regressed with time. Extra on that later.
I additionally engaged with KeraVision and took part within the scientific trials that led to FDA approval of the PMMA Intacs intracorneal ring segments in 1999 for the therapy of low myopia. This process was quickly changed by PRK and LASIK for the therapy of myopia, with each offering superior refractive outcomes. Once more, I discovered Intacs useful in decreasing myopia and astigmatism in choose keratoconus sufferers. With the arrival of the IntraLase femtosecond laser, channel creation turned obtainable, permitting less complicated and extra correct placement of Intacs. Working in our office-based surgical procedure excimer/femtosecond laser suite with the Visx excimer laser adjoining to the IntraLase femtosecond laser, I might place one 0.45 mm inferior Intac and rotate it to the best place to cut back corneal astigmatism utilizing the Visx ring mild mire as a information for clever placement. In lots of circumstances, I might then refine the end result with CK. These procedures have been each off-label functions of an FDA-approved gadget. Our observe, Minnesota Eye Consultants, sought and acquired institutional overview board approval, supplied complete knowledgeable consent and thoroughly adopted our outcomes. Corneal tissue addition keratoplasty (CTAK), as described within the accompanying Healio | OSN cowl story, has now changed Intacs in our observe, and my companions David R. Hardten, MD, FACS, and Elizabeth A. Davis, MD, FACS, are early adopters and advocates. With plastic implants or CTAK, we now had a minimally invasive surgical therapy that would enhance a keratoconus affected person’s refraction with out PK. Our outcomes confirmed we might scale back each myopia and astigmatism however not absolutely arrest keratoconus development. Nevertheless, many sufferers regained useful imaginative and prescient with out a contact lens, permitting them to make use of spectacles within the evenings and weekends.
FDA approval of the excimer laser for PRK and PTK occurred within the mid to late Nineteen Nineties, including it to our armamentarium for treating myopia and astigmatism, and we discovered a superficial excimer laser therapy not exceeding 40 µm of tissue elimination was effectively tolerated within the keratoconus eye as a ultimate therapy. As soon as corneal cross-linking was accepted, we turned much more safe in utilizing this device, and superior therapy algorithms, together with wavefront and topography-guided software program, additional enhanced the outcomes.
Minnesota Eye Consultants then engaged in a 2-decade sequence of corneal cross-linking scientific trials with CXLO, now Epion Therapeutics, and Avedro, now Glaukos. We’re getting into our tenth yr since epithelium-off corneal cross-linking was FDA accepted, and this process has revolutionized the therapy of keratoconus. An arrest of the progressive and disabling myopia and irregular astigmatism is achieved with a single cross-linking therapy in 95% of sufferers and practically 100% with two or extra therapies. As well as, primarily based on the 6-year follow-up of the sufferers handled by Theo Seiler, MD, PhD, and his collaborators, the keratoconus affected person who undergoes cross-linking can anticipate a 3 D discount in myopia and 1 D to 2 D discount of their astigmatism over 3 years after which stability.
The aim right this moment is to acknowledge the early keratoconus affected person, ideally of their teenagers, and cross-link them on the earliest stage as soon as development is confirmed. This requires sturdy collaboration between optometry and ophthalmology, which at current is lower than superb however with the arrival of higher therapies for progressive myopia will be anticipated to enhance. Sooner or later, I see progressive myopes being captured and handled with behavioral modification, specialised optical correction and pharmacologic brokers beginning with low-dose atropine eye drops starting at age 4 to six years. The keratoconus sufferers will evolve out of the progressive myopes at about age 12 to 14 years and ought to be acknowledged instantly by the attention care skilled managing their progressive myopia and handled at an early stage. This therapy shall be helpful in not solely halting keratoconus but in addition in decreasing any coexistent myopia and astigmatism, a win-win. If this state of affairs of early analysis and therapy of keratoconus earlier than vital myopia and irregular astigmatism manifests, therapy with glasses, tender contact lenses and, as soon as the affected person is mature, refractive surgical procedure ought to be adequate for optical correction, and PK as a keratoconus therapy will development towards zero.
Nevertheless, we are going to nonetheless have many keratoconus sufferers with vital refractive error to deal with, and cross-linking together with human tissue addition lamellar keratoplasty (corneal allogenic intrastromal ring segments/CTAK) mixed in choose circumstances with customized excimer laser wavefront or topography-assisted PRK (and sometimes CK) are exhibiting nice promise. I name this mixture of therapies for keratoconus “refractive cross-linking,” and a few of the procedures are third-party pay and a few are money pay. Whether or not the procedures are greatest accomplished with so-called simultaneous same-day surgical procedure or sequentially, together with the best order and timing, is being investigated by many modern pioneers. In my expertise, some sufferers can expertise life-changing enhancements in each greatest corrected and even uncorrected imaginative and prescient. I’ve seen some keratoconus sufferers completely depending on a tough contact lens for helpful imaginative and prescient progress to an end result that permits them to perform effectively completely unbiased from contact lenses or spectacles. It is a modern-day miracle for the keratoconus affected person achieved by a multi-decade collaboration between business and ingenious ophthalmologists, with extra to return.
For extra data:
Richard L. Lindstrom, MD, will be reached at rllindstrom@mneye.com.
Sources/Disclosures
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Disclosures:
Lindstrom stories have monetary disclosures for Alcon, CorneaGen, Epion Therapeutics, Glaukos, Johnson & Johnson Imaginative and prescient, Minnesota Eye Consultants and Unifeye Imaginative and prescient Companions.
