04/10/2021
Treatment options for keratoconus have changed over the years…
I shared my thoughts on the changing landscape of keratoconus management and my clinical experience with the disease in an article in the news magazine EyeWorld Asia-Pacific (Vol 16 No 2, Jun 2020, Pg 33).
The article can be found through the following links:
https://www.drcordeliachaneye.com/media/
http://eyeworldap.apacrs.org/ewap/2020/june/8/index.html
For those of you who are unable to view the article, here are the key points:
THE CHANGING LANDSCAPE OF KERATOCONUS MANAGEMENT
Back in the early 1990s when I was a Resident in Ophthalmology, keratoconus patients had limited options. Treatment was confined to glasses, contact lenses and penetrating keratoplasty.
Fast forward three decades and the landscape has changed tremendously. Management paradigms have shifted to target not only improvements in functional visual acuity but also cessation of disease progression and simultaneous complete correction of the refractive component of keratoconus. Keratoconus is also identified earlier in the disease where vision is relatively preserved due to the existence of advanced topography systems and the advent of cosmetic refractive surgery, where asymptomatic patients present themselves to be screened for suitability.
There have been remarkable improvements in contact lens technology and besides rigid gas permeable (RGP) lenses, other available options include piggy-back, hybrid and scleral lenses. The game-changer in keratoconus management has to be corneal collagen cross-linking (CXL), a procedure which promises to re**rd keratoconus progression and afford some extent of refractive correction in suitable patients. A technically straight-forward procedure, CXL is not without its issues. Post-operative pain, delayed epithelial healing, risk of infection and keratocyte loss with corneal haze, melting and opacification together with contradictory reports of its efficacy have plagued the procedure. The original Dresden protocol has had many modifications to address the inconsistencies of the effectiveness of the technique, but these modifications too have had their inconsistencies. However, CXL is still currently widely used to treat keratoconus as it has fulfilled an unmet need in keratoconus management, with its advantages prevailing over the disadvantages.
A complete surgical approach in keratoconus management has become increasing appealing with some surgeons combining CXL with adjunctive refractive procedures to re**rd the ectatic process and enhance functional vision. These “CXL-plus” procedures include CXL with photorefractive keratectomy (PRK), intrastromal corneal ring segments (ICRS), phakic intraocular lenses, conductive keratoplasty or a combination of these. While results of CXL plus PRK have been encouraging, there are still questions on its long term effect on the biomechanical stability of the cornea. The downstream effect of CXL-induced stromal changes that cause persistent variations in pachymetric and topographic indices over time make outcomes unpredictable and excimer laser treatment planning tricky. With ICRS, issues with accurate ring placement without established nomograms and decreased predictability of refractive outcomes makes ICRS a less favoured procedure. Most of the published studies on these CXL-plus procedures are relatively small case series, with variable findings among different protocols. Larger randomized controlled trials with longer follow-up periods are thus required.
To date, there are no specific guidelines on keratoconus management, with individual surgeons having their own treatment algorithms. With such a wide armamentarium of procedures now available to our keratoconus patients, how aggressive should we be?
Eye rubbing is an important cause of keratoconus that is often overlooked or inadequately emphasized in clinical practice. Eye rubbing should be addressed or excluded in every keratoconus patient before CXL or any surgical intervention is considered, as cessation of eye rubbing alone has been found to arrest or re**rd the progression of keratoconus in some patients. We should be open to the “plus” in CXL-plus procedures but not be overzealous, as many keratoconus patients with stabilized corneas are able to achieve good functional vision with well-fitted modern day RGP or scleral lenses. Besides, not all keratoconus patients demand spectacle or contact lens independence, which is difficult to achieve even with CXL-plus procedures.
As clinicians, it is important to select the optimal treatment options for our patients and individualize them to their needs. For some of these patients, less is the new more.
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