Eric D. Donnenfeld, MD

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For practices yet to jump into CXL, changes may warrant a closer look.


	
	Corneal collagen crosslinking (CXL) for the treatment of keratoconus is a procedure that has stood the test of time.
	
	Available in Europe for the past 15 years and nearly 4 years in the United States, it is by now well established as a great option for patients with progressive keratoconus.


	
	Unlike any other treatment for keratoconus, CXL is effective at slowing or halting disease progression,

 while improving vision- and health-related quality of life.

Many cornea practices were early adopters of CXL technology, but the time may be right for comprehensive ophthalmologists to explore this technology, as well. CXL is certainly well within the skill set of any anterior segment surgeon.
	
	

Traversing the CXL pathway: Where do we go from here?


	
	As our practices emerge from the global health and financial crisis caused by the COVID-19 pandemic, CXL is a procedure that can begin sooner than some others, given its minimally invasive nature and younger candidate pool.
	
	Recent data suggest a higher level of patient need for treatment than previously thought.

 And we now have a much clearer reimbursement path and lower barriers to entry than existed in the early years of CXL availability in the United States.
	 

Higher incidence of prevalence of keratoconus

 has generally been accepted to be approximately 1 in 2,000 or 1 in 3,000, making it a relatively rare condition.


	
	More recently, an analysis of 4.4 million patients covered by the Netherlands’ largest health insurer found an annual incidence and estimated prevalence of keratoconus that is 5- to 10-fold higher than historical estimates 


	
	The researchers found that keratoconus affected about 1 in 7,500 people in the 10- to 40-year-old age group each year, for an overall prevalence within the population of 1 in 375 people, or 265 per 100,000.

A number of factors have likely contributed to this jump in prevalence. First, computer-based corneal imaging technologies have improved dramatically, leading to earlier and more accurate diagnoses.

Corneal collagen crosslinking imperative in paediatric keratoconus 


	
	We know that keratoconus has a genetic predisposition, which is often compounded by iatrogenic factors such as eye rubbing, and that it is more common in patients with longer axial length and more highly myopic eyes.


	
	So, with rising rates of myopia/high myopia and obesity, which have been associated with sleep apnea and eye rubbing, it is not surprising that we are seeing more cases of keratoconus.

Given the higher estimates of keratoconus prevalence in the population, we likely do not have enough cornea specialists or current CXL providers to treat everyone who would benefit right now. There is a need for CXL; providing the procedure is a significant service to the community.
	
	

PACK-CXL researchers continue to clear hurdles of topical drugs


	Early on, as with many new ophthalmic procedures, there were problems with reimbursement for CXL that made many practices hesitant to offer it.
	
	Today, the majority of commercial health plans in the United States-representing more than 95% of commercially covered lives-recognize CXL with the FDA-approved drugs and device as a covered service, so the barriers to launching CXL within a practice have been significantly lowered. 

The procedure can be performed in the office or in a surgery center environment.  There is only 1 CXL system approved in the United States: The KXL system, used along with Photrexa Viscous (riboflavin 5’-phosphate in 20% dextran ophthalmic solution) and Photrexa (riboflavin 5’-phosphate ophthalmic solution) (all from Avedro, now part of the Glaukos Corneal Health Division).
	
	

Estimating the total corneal power key in keratoconus patients 


	
	The return on investment is rapid, with most practices able to recoup their investment in a year or less. The company has recently expanded both its reimbursement support and financing options to ease the acquisition process for practices.  

The ophthalmic solutions now have a J code for reimbursement, so there is not as much concern about receiving adequate compensation for needed supplies.
	
	The procedure typically takes a total of 1 to 2 hours, so practices need to allocate appropriate clinical staff time and space in the office for a procedure of that duration.  

CXL is indicated and reimbursed for progressive keratoconus, so it is important to establish procedures for documenting progression. This process does not need to be daunting.
	
	

Keys to assessing true crosslinking outcomes


	Although the ideal would be to have serial topographies demonstrating progression, we also know that the chance of progression in patients younger than 25 years of age is very high, and historical topography may not be available.  

In these younger patients, a significant increase in the manifest refraction (myopia or cylinder) over the course of 1 to 2 years with a keratoconus topography map may be sufficient evidence of progression. In the absence of patient records, prior spectacles may be useful in evaluating changes in refraction.
	
	Although keratoconus progression slows or stops, on average, by age 40, there are certainly individuals who progress well beyond the typical range, into their 60s.

Microscopy study suggests stem cell success in keratoconus 


	
	In my experience, these patients are most likely to be significant eye rubbers, particularly with floppy eyelid syndrome

With a clear reimbursement pathway and fewer hurdles to beginning CXL, ophthalmologists can now viably perform the procedure, meeting a significant patient need.

This, of course, also requires a redoubling of efforts to educate local physicians and optometrists about keratoconus and CXL. I believe we are moving rapidly toward a new paradigm in which any young patient who develops myopia and astigmatism should undergo corneal topography.
	
	We need low-cost, accessible topographers so that more optometrists can routinely perform this diagnostic test as part of their exam. Making the diagnosis and undergoing CXL even a year or 2 earlier can mean the difference between a lifetime of quality vision with glasses and the need to wear specialty rigid gas permeable or scleral contact lenses.
	
	Patients who are able to successfully remain in contact lenses have a reduced risk of requiring a corneal transplant in the future.

 We owe it to our patients to give them the opportunity to achieve the best possible outcomes.
	
	

Dr. Donnefeld is in private practice with Ophthalmic Consultants of Long Island in Garden City, New York. He is a trustee of Dartmouth Medical School and a clinical professor of ophthalmology at New York University Medical Center. He is a consultant for many ophthalmic companies, including Glaukos. 

Gomes JAP, Tan D, Rapuano CJ, et al; Group of Panelists for the Global Delphi Panel of Keratoconus and Ectatic Diseases. Global consensus on keratoconus and ectactic diseases. 

Hersh PS, Stulting RD, Muller D, et al; United States Crosslinking Study Group. United States Multicenter Clinical Trial of Corneal Collagen Crosslinking for Keratoconus Treatment. 

Shetty R, Pahuja NK, Nuijts RM, et al. Current protocols of corneal collagen cross-linking: visual, refractive, and tomographic outcomes. 

Raiskup F, Theuring A, Pillunat LE, Spoerl E. Corneal collagen crosslinking with riboflavin and ultraviolet-A light in progressive keratoconus: ten-year results. 

Cingu AK, Bez Y, Cinar Y, et al. Impact of collagen cross-linking on psychological distress and vision and health-related quality of life in patients with keratoconus. 

Brooks NO, Greenstein S, Fry K, Hersh PS. Patient subjective visual function after corneal collagen crosslinking for keratoconus and corneal ectasia. 

Godefrooij DA, de Wit GA, Uiterwaal CS, et al. Age-specific incidence and prevalence of keratoconus: a nationwide registration study. 

Kennedy RH, Bourne WM, Dyer JA. A 48-year clinical and epidemiologic study of keratoconus. 

Masiwa LE, Moodley V. A review of corneal imaging methods for the early diagnosis of pre-clinical keratoconus. 

. pii: S1888-4296(19)30104-9. doi: 10.1016/j.optom.2019.11.001

Mas Tur V, MacGregor C, Jayaswal R, et al. A review of keratoconus: diagnosis, pathophysiology, and genetics. 

Gokul A, Patel DV, Watters GA, McGhee CNJ. The natural history of corneal topographic progression of keratoconus after age 30âyears in non-contact lens wearers. 

Donnenfeld ED, Perry HD, Gibralter RP, et al. Keratoconus associated with floppy eyelid syndrome. 

Naderan M, Rezagholizadeh F, Zolfaghari M, et al. Association between the prevalence of obstructive sleep apnoea and the severity of keratoconus. 

Dana MR, Putz JL, Viana MA, et al. Contact lens failure in keratoconus management. 

Articles

Is the time right for crosslinking?

While the number of candidates for cataract surgery continues to rise, the number of cataract surgeons is declining. Physicians who are willing to make a commitment to excellence in their practice and go that extra mile can succeed.

As the global population that is prone to developing cataracts continues to grow, ophthalmologist could be facing challenges as people live longer, increasing their odds for cataracts. Though this is a worldwide issue, in the United States, surgeons are performing about 

It is estimated that there are about 30 million people worldwide who have 

 of 20/400 or worse, and there are almost 250 million people who have cataracts between the range of 20/60 and 20/200. Cataracts are endemic.

As technology improves, patients are more willing to undergo cataract surgery at an earlier stage as the reward of cataract surgery becomes much greater than the risk associated with it because it provides an opportunity to improve their quality of life.

Here are my thoughts on the ever-changing current landscape of cataract-refractive surgery. Patients’ growing confidence in cataract surgery is a byproduct of better technology. As technology has improved, it has made cataract surgery not only more efficacious but also safer. When I evaluate cataract surgery, I look at a procedure that has become extraordinarily successful, with much less risk and much greater reward.

Cataract surgery, for many patients, has become the “

” because they can reverse the aging process and restore natural vision in a way that was not possible before. When I first started practicing in 1985, cataracts were the defining moment of old age, and postoperative quality of vision was significantly diminished. Therefore, it was common to wait until patients’ visual acuity was 20/70 before performing surgery.

Our goal was to remove the cataract and restore the patient’s vision with glasses. Now we can remove the cataract to improve their quality of vision and remove their refractive error- including hyperopia, myopia, and astigmatism. We can also improve their vision at near as well-with either monovision, 

, or multifocal IOLs-to resolve refractive error and in some cases presbyopia as well.

Study: Intracameral moxifloxacin reduces endophthalmitis cases

During my career, I have noticed an extraordinary increase in patient expectations, and that frightens many cataract surgeons. I view that in a different light and consider demanding patients to be opportunities to meet or exceed their expectations. Demanding patients, while more challenging, also present an opportunity to provide patients with better-quality vision.

These are the patients who need to have the best diagnostic instruments available to make sure the cataract surgery is done with the greatest chance of achieving emmetropia.

It means you should have good surgical technique, and you should use the best equipment available to achieve these results. Part of any refractive cataract surgery procedure is having an “escape valve,” a technique for resolving residual 

That “escape valve” might be limbal-relaxing incision, an IOL exchange, 

LASIK, PRK, or small-incision lenticule extraction (SMILE)

. New technologies help improve outcomes, allowing refractive cataract surgery to truly come of age. Surgical technologies should allow cataract surgery that is extremely accurate, low risk, and effective.

That means using advanced diagnostic technology to make certain that we diagnose patients correctly with cataracts, rule out concomitant pathologies, implant the correct IOL with a high degree of accuracy, and treat astigmatism accurately.

Cataract patients may benefit from new drug-delivery methods

Refractive cataract surgery began with the advent of optical biometry (IOLMaster, Carl Zeiss Meditec) because it dramatically improved the accuracy of IOL measurements that allow us to achieve emmetropia in significantly more patients than we ever could with previous generations of biometry.

As optical biometry has improved, we have new generations of this technology that provide telocentric keratometry, which is able to locate the fovea and diagnose foveal disease; it can see through dense cataracts and improve the accuracy of IOL power and toric IOL measurements.

Macula OCT (Cirrus-HD OCT, Carl Zeiss Meditec)

 is another diagnostic technology that I use preoperatively to image macular pathology and health prior to cataract surgery. When I can view the macula, I can more accurately advise patients on what IOL is in their best interest because I have different levels of expectations for patients who have macular pathology, which is difficult to diagnose just by visualizing the retina.
	
	I also use a 

 to familiarize myself with the health of the cornea and the existence of astigmatism. Being able to document the cylinder quantitatively and qualitatively is predicated on having a good topography image. It aids in managing both their astigmatism and irregular astigmatism, which may change my choice of IOLs.

Once diagnostic decisions have been made, the next step is the execution of the cataract surgery. In our operating room, we also use a surgical microscope with stereo coaxial illumination 

For astigmatism management, we use a computer-assisted cataract surgery instrument (Callisto, Carl Zeiss Meditec), which takes information from the optical biometry to find the steep axis of the cornea and is instrumental for accuracy of toric IOL placement.

) that have great optics with aspheric optics as well, including EDOF IOLs and multifocal lenses. I have found that low-add lenses provide better-quality vision.

PEDIG focusing on binocular activities for amblyopia

Out-of-pocket spending is now more frequent and accepted among patients. Patient-shared billing has become an important part of cataract surgery in the United States as refractive outcomes are not covered by 

Providing technology that improves the accuracy of refractive outcomes or treats astigmatism or presbyopia, benefit patients’ quality of life. These are technologies that patients want, and they believe that it’s a worthwhile investment in their future.

There is little that patients will benefit from more than cataract surgery. Many patients are willing to pay out of pocket for the best technology that meets their needs. As the technology gets better, patients are more willing to use patient-shared billing because the delta between the traditional surgery and the premium surgery has become more significant.

We anticipate that 2019, in hindsight, will have been another great year for cataract surgery. The number of surgical patients continues to increase, along with their expectations. 

The number of cataract surgeons is declining, however

Surgeons who are willing to make a commitment to excellence in their practice and go that extra mile to give patients the quality of vision they desire, will have extraordinarily successful practices, grateful patients, and will be able to practice ophthalmology at the highest possible level. Refractive-cataract surgery is the future of our profession, and one of the most rewarding aspects of being an ophthalmologist.

Image-reading accuracy Increases with deep-learning DR algorithms

Dr. Donnenfeld is a consultant to AcuFocus, Alcon Laboratories, Allergan, Aquesys, Bausch + Lomb, Beaver-Visitec International, Glaukos, Johnson & Johnson Vision, Novaliq, Ocular Therapeutix, Omeros, Pfi zer, and Shire Pharmaceuticals. He consults and has investment interests in Katena, Novabay Pharmaceuticals, PRN Pharmaceuticals, and RPS Diagnostics.

1. Market Scope estimate based on WHO 2014 Global Data on Vision Impairment.

2. Chandra S. U.S. Consumer Confidence Just Hit Its Highest Level in Almost 17 Years. https://www.bloomberg. com/news/articles/2017-10-31/u-sconsumer-confidence-index-rises-tohighest-level-since-2000 Accessed May 13, 2019.

Demographic shifts, improving technology continue to bring patients in at younger age

Eric D. Donnenfeld, MD

Articles

Is the time right for crosslinking?

Refractive-cataract surgery: Overview of the current landscape

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