Clark Chang, OD, MSA, MSc, FAAO, recently shared what he considers to be the top-five innovations in eye care during a session at SECO 2016.
Atlanta-Clark Chang, OD, MSA, MSc, FAAO, recently shared what he considers to be the top-five innovations in eye care during a session at SECO 2016.
It’s all about precision and control with femtosecond laser-assisted cataract surgery, says Dr. Chang.
“Just as we can use femtosecond laser-which is a great, great invention-to assist in kerotoplasty, we can now use femtosecond laser to assist in cataract surgery,” he says. “And because of demographic shifts, you and I are going to be taking care of a lot of cataract patients, so therefore, I think this is one thing that has a lot of impact going forward with regard to patient outcome after cataract surgery.”
Dr. Chang says that outcomes were already good with the manual cataract extraction method, but manual capsulorhexis can be difficult.
“One of the most important things for a successful outcome in a cataract surgery is actually the capsulorhexis-the act of tearing apart the very thin membrane on the anterior capsule, making it as symmetrical-hopefully-as possible,” he says. “The important thing about having a symmetrical capsule is that we know the capsule contracts slightly after an intraocular lens (IOL) is inserted, so the contraction can change the position of the lens, and if it is not done symmetrically, the lens can tilt.”
Femtosecond laser offers perfect centration, no radial tears, and easy and complete removal of the capsule. Dr. Chang says that because the procedure is more predictable and precise, it has more reproducible outcomes.
“If a surgeon thinks that automated instruments are going to replace optometrists, I’m going to tell them that lasers are going to replace them-so I’m not afraid,” says Dr. Chang.
It is not uncommon for a patient to not be completely happy with the outcome of his cataract surgery, and that outcome could be blamed on a number of different factors.
“What happens when a surgeon no longer wants to exchange the lens but the IOL is already implanted? Well, a light-adjustable IOL may be a solution,” says Dr. Chang.
Ophthalmology Times: Light-adjustable lens addresses challenges of refractive target concerns
In the post-operative phase, a light-adjustable IOL can change its geometric shape and therefore lens power with UV exposure. Changing the lens power can happen in stages, says Dr. Chang.
“You can wait a couple of days or weeks and see if that is the refractive power that is suitable for your patient-if it is, then you irradiate the whole lens and the final confirmation of the lens will be locked in,” he says. “This does offer a very nifty solution to the post-refractive surprises in a cataract case.”
Dr. Chang says that presbyopes present a unique challenge for eyecare providers.
“If a patient is age 45 or 50, I’m not going to push that patient to get cataract surgery just to get a premium IOL,” he says. “And if that patient chooses not to wear spectacles or multifocal contact lenses, is there something that we can do?
“There is that missing gap, I feel, in our patient population segment where they don’t seem to have any surgical choices,” he says. “So, a corneal inlay may be a suitable idea.”
Related: New correction option for presbyopes
Dr. Chang says there are three strategies in use in corneal inlays:
• Bifocal or refractive lens power (Flexivue, Presbia)
• Aspheric enhanced depth of focus (Raindrop, ReVision Optics)
• Pinhole enhanced depth of focus (Kamra, AcuFocus)
Using Kamra as an example, Dr. Chang says the corneal inlay is easily implanted and reversible with excellent outcomes in more than 20,000 inlays implanted to date. The design allows for ocular assessments and secondary surgical procedures.
“One thing I have found is that optimization of the ocular surface seems to be extremely important in a post-inlay situation,” he says. “It shows you how important the tear film is to everything we do.”
On that note, Dr. Chang says that our understanding of dry eye has evolved, thanks in part to new dry eye diagnostic technology. And osmolarity is becoming the gold standard in dry eye testing, he says.
“The good thing is that we no longer have to collect a huge amount of tear volume like we used to in a laboratory setting where you had to collect 5 microleters-because let me tell you, if you can collect 5 microleters, that patient probably doesn’t have dry eye,” he says.
Another important sign of dry eye is inflammation, which can be identified by evaluating MMP-9 with the InflammaDry test (RPS). Both MMP-9 and osmolarity testing can be combined to dictate your treatment algorithm, says Dr. Chang.
Dr. Chang says one of the most feared outcomes of PRK or LASIK is ectasia.
“You don’t want to misscreen your patient and perform this procedure that you think is beneficial, and then a few years down the road, your patient turns out to have ectasia,” he says. “Is there anything we can do to strengthen our defense and be able to pick out these patients better? Well, corneal biomechanics testing may be an answer.”
Using an air pulse and observing the time it takes the cornea to cave in and come back to normal shape gives you a sense of the viscoelastic properties of the cornea and indirectly reflects the strength of the cornea, says Dr. Chang.