How a crash landing became a successful failure

June 6, 2015

In his latest blog, Mark Packer, MD, writes of a surgical tale that led him to discover aberrations can sometimes be your friend.

Editor’s Note: Welcome to “Eye Catching: Let's Chat,” a blog series featuring contributions from members of the ophthalmic community. These blogs are an opportunity for ophthalmic bloggers to engage with readers with about a topic that is top of mind, whether it is practice management, experiences with patients, the industry, medicine in general, or healthcare reform. The series continues with this blog by Mark Packer, MD, FACS, CPI. The views expressed in these blogs are those of their respective contributors and do not represent the views of Ophthalmology Times or UBM Advanstar.

 

Fred was a private pilot in his mid-50s who had an unusual right eye, an equally unusual complication during surgery and, in the end, a completely satisfactory result.

Fred’s left eye was relatively normal, with just a little farsightedness and astigmatism, + 0.50 + 0.25 X 180, with 20/15 best-corrected visual acuity (BCVA).

His right eye was highly myopic and also had significant astigmatism, - 9.25 + 4.75 X 63.  Nevertheless, he had a surprisingly good BCVA of 20/30+.  Corneal topography showed some mild irregularity. 

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He had virtually no nuclear opalescence, just normal age-related yellowing.

He had been treated for amblyopia as a child, but most of his life he had just ignored the eye. There were times when he tried to correct the vision with a contact lens, but he did not find wearing a lens comfortable because he had a facial palsy on the same side as his odd eye. 

In his case, an idiopathic Bell’s palsy had persisted for many years, accompanied by intermittent symptoms of exposure keratopathy, usually during dry, cold, or windy weather.  Slit lamp exam showed 1 mm to 2 mm lagophthalmos, and just a few dots of punctate staining inferiorly on the cornea.  He had a decent Bell’s reflex, and only occasionally used artificial tears or gels. 

Fred had no trouble getting a private pilot’s license.  Apparently FAA standards for general aviation are not as strict as one might think.

Fred had come to see me to find out if I could make the vision in this eye “normal.”  By “normal,” he meant like his other eye had been when he was 25.  In other words, he’d like to be able to see clearly at distance and near and “everywhere in between” without glasses.

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Fred was also a close friend of one of my employees.  Fred’s wife and my employee shared a lot through their church.  My employee had encouraged Fred to come see me.  Personal relationships like that always create a bit more pressure for a great result.

So, I was pursuing a quest for perfect vision with freedom from eyeglasses in the face of high myopia and astigmatism, dry eye due to facial palsy, and perpetual updates on his surgical outcome. 

Next: "Good thing I love a challenge"

 

Good thing I love a challenge.

As I mentioned, Fred had a private pilot’s license, which apparently does not require perfect vision in both eyes.  However, he felt he could be a better pilot if he used both eyes when flying.  I tended to agree. 

Also, he was frustrated by having to find reading glasses to do his pre- and post-flight paper work.

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Fred struck me as a very practical man.  He was not expecting a miracle.  He just wanted to know what science had to offer. 

We talked about the halos that come with a multifocal IOL, and he begged off.  I was just as glad, because the intermittent dry eye from his eyelid palsy would degrade his vision with a multifocal lens.  He cherished the idea of having crisp, clean vision in his right eye-and he had a good idea of what that should look like, based on the vision in his left eye. 

Next, I brought up the option of a Crystalens accommodative IOL (Bausch + Lomb), and that grabbed Fred’s imagination (the Trulign toric IOL was not yet available at the time).  Even though he knew he would likely still need glasses for reading small print, he loved the idea that the view out the windshield and the view of the instrument panel would very likely be crystal clear. 

I recommended doing relaxing incisions to reduce the amount of astigmatism at the time of the lens surgery, and then doing a final correction with the excimer laser once everything had settled down, about 6 weeks later.  Because of the dry eye, I told him he would do better to have PRK rather than LASIK, although I also warned him that, due to the mild exposure, his epithelium might take up to a week to completely heal.  He knew he would have to wear a soft contact lens during that time.

Fortunately, Fred’s peripheral fundus exam was normal, and he had a complete PVD, meaning that his risk of retinal complications from lens exchange was probably not unacceptably high.  His axial length, at 26 mm, was enough to give one pause. 

Going into the operating room, the plan was to remove his natural lens, implant the Crystalens and then construct relaxing incisions in his cornea to reduce the astigmatism, measuring and titrating the effect with intraoperative aberrometry.  

Next: Trouble brewing

 

When planning for the Crystalens, it is my standard procedure to discuss a back-up IOL with the patient.  The reason for deciding in advance on a second choice with the Crystalens is that it really demands a pristine, perfect capsule for optimal results.  If there is even a slightly decentered capsulorhexis, a small anterior capsular tear or a bit of retained cortex, not too mention a posterior capsular problem, the accuracy of the postoperative refractive result will generally suffer, and the risk of an anterior vault of Z-syndrome will rise. 

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It is far better to have a plan in place in advance, so the need to switch to a back-up IOL does not come as a complete surprise to the patient or the surgeon. 

In the discussion with Fred, we had already determined that a multifocal IOL was not appealing.  The back-up plan was a monofocal IOL, either in the bag or in the sulcus. 

The trouble with unusual eyes is that they tend to be unusual in more ways than one.  As I performed my routine cortical cleaving hydrodissection, after a technically perfect capsulorhexis, I was expecting the nucleus to easily hydro-express out of the capsule, as relatively clear lenses tend to do.  However, instead of the lens prolapsing anteriorly, Fred’s posterior capsule split open and his lens dropped posteriorly.   

At that point the Crystalens was obviously no longer an option.  And, of course, Fred would need a vitrectomy in the next day or so.  There was just nothing good about this situation.  I placed an AQ 2010 IOL (STAAR surgical) in the sulcus, completed the relaxing incisions with the aid of intraoperative aberrometry, and was done for the day.

Fortunately, Fred was a sober and practical sort of guy.  He understood what had happened and what more had to be done to rectify it.  He knew that his eye was unusual, and maybe half expected things to go awry.  In any case he didn’t moan or complain but just got ready to take the next step with the retina surgeon, see where he landed, and go from there.

Fred came back to see me 2 weeks after his vitrectomy.  He seemed moderately happy, or at least equanimous.  He cracked a half smile (due to his facial palsy) and said he was seeing, “Okay.”  In fact, his uncorrected acuity was 20/30.  He also refracted to 20/30+ with – 0.50 + 0.75 X 75.    Most surprisingly, he could read J3 at about 16 inches, and J2 at 24 inches. 

Next: "I didn't bother to tell Fred"

 

I didn’t bother to tell Fred that this result would have been considered a success even with the Crystalens, particularly given his mild amblyopia.  Instead, I refunded him his premium IOL fee, shook his hand, and asked him to come back in about a month for a check up.

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I figured I’d be getting frequent updates anyway from my employee, his close friend. 

Post Script

Uncorrected near and intermediate range visual acuity with a monofocal IOL can sometimes surprise. 

For example, in the clinical investigation of the Array Multifocal (AMO), “The proportion of eyes achieving J3 (20/40) or better uncorrected near visual acuity was 86% (87 of 101) and 49% (49 of 101) for the multifocal and monofocal eyes, respectively”(measured at 14–18 in).[1]   In the published report of the Tecnis Multifocal (AMO), mean binocular best-corrected distance defocus visual acuity with natural pupil size for subjects implanted with the Tecnis multifocal IOLs or the CeeOn monofocal IOLs demonstrated equivalent acuities at 26 inches, a distance generally regarded as “intermediate range.”[2]

 A small amount of residual myopic astigmatism, such as my patient in this narrative demonstrated, is known to improve uncorrected near vision.[3]  Pupil size and corneal aberrations may also contribute to pseudoaccommodation:  “ . . . in an optical system with a moderate or large amount of wavefront aberrations, the polychromatic modulation transfer function peak value is relatively low, and these values drop more slowly when defocus is added.”[4]

The Crystalens remains the only IOL to have received a labeling indication for accommodation from the FDA (its companion toric IOL, the Trulign, has received a claim for “increased spectacle independence and improved uncorrected near, intermediate, and distance vision,” but not for accommodation). 

While clinical measurements have demonstrated approximately a diopter or more subjective accommodation for both the Crystalens and the Trulign, with intermediate range vision superior to near, objective measurements of accommodation have produced variable results. 

Next: "Sometimes . . . aberrations can be your friend"

 

However, Perez-Merino et al. have produced evidence that reconciles this apparent contradiction by demonstrating statistically significantly greater depth of focus with the Crystalens compared with monofocal IOLs and young phakic eyes.  They write, “the higher amount of aberrations in Crystalens eyes in comparison with young eyes, likely arising from A-IOL tilt and increased corneal aberrations, results in increased depth of focus, which may explain some functional near-vision performance in these eyes (by pseudoaccommodation, rather than by true accommodative changes in optical power).”[5]  

Sometimes, as it turns out, aberrations can be your friend. 

 

[1] Steinert RF, Aker BL, Trentacost DJ, Smith PJ, Tarantino N.   A prospective comparative study of the AMO ARRAY zonal-progressive multifocal silicone intraocular lens and a monofocal intraocular lens.  Ophthalmology. 1999;106:1243-1255.

 

[2] Packer M, Chu YR, Waltz KL, Donnenfeld ED, Wallace RB 3rd, Featherstone K, Smith P, Bentow SS, Tarantino N.   Evaluation of the aspheric Tecnis multifocal intraocular lens: one-year results from the first cohort of the food and drug administration clinical trial.  Am J Ophthalmol. 2010;149:577-584.e1.

 

[3] Huber C.   Planned myopic astigmatism as a substitute for accommodation in pseudophakia.  J Am Intraocul Implant Soc. 1981;7:244-249.

 

[4] Yeu E, Wang L, Koch DD.   The effect of corneal wavefront aberrations on corneal pseudoaccommodation.  Am J Ophthalmol. 2012;153:972-981.e2.

 

[5] Pérez-Merino P, Birkenfeld J, Dorronsoro C, Ortiz S, Durán S, Jiménez-Alfaro I, Marcos S.   Aberrometry in patients implanted with accommodative intraocular lenses. Am J Ophthalmol. 2014;157:1077-1089.