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Second lens-based surgery can correct dysphotopsia after initial lens exchange
Some patients are unable to adjust to unwanted visual symptoms after initial refractive lens exchange. A second exchange may be needed.
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The development of presbyopia-correcting IOLs has improved upon our already successful lens replacement surgery, whether in the form of refractive cataract surgery or clear lens exchange.
David C. Brown |
As with any new medical device, there have been some unexpected consequences related to these advanced lens technologies. One of the most discouraging sequelae for patients is the dysphotopsia that can be associated with acrylic lenses, which occasionally requires a second surgery due to patient dissatisfaction with postop vision. Dysphotopsia can include various visual symptoms, such as reflections, temporal darkness or visual field defect, unsettling vision arc, glare, central flash and halos, all of which can be visually incapacitating.
Many patients are ultimately able to adjust to these symptoms due to neural adaptation, in which it is presumed that the brain learns to act as a filter to cancel the disturbing phenomena. There are some patients, however, who are never able to adjust to the unwanted symptoms. Additionally, some multifocal lenses have been found to cause glare, halos and loss of contrast sensitivity.
Counseling the patient to adjust to these unwanted symptoms, or to “wait it out,” is not an option for some patients. This article presents brief case studies of patients who were adamant that their visual problems be corrected immediately via a second lens surgery.
Case 1
A 66-year-old man presented with complaints of difficulty with halos around lights at night when driving and the inability to see at distance, even with spectacle overcorrection. The patient did not feel that he could carry on with his vision, and he requested help, even if a second surgery was needed.
He had undergone implantation of the Alcon ReSTOR apodized diffractive lens in the right eye about 1 month before and in the left eye 3 weeks before. Manifest refraction was –1.50 + 0.25 × 105 = 20/30 in the right eye, and –1.75 +0.25 × 180 = 20/25 in the left. In addition to the distance complaints, reading vision was “double” in each eye, he reported. Overcorrection with spectacles did not improve vision or lessen symptoms.
The examination revealed well-centered ReSTOR lenses in both eyes. The capsules were clear, and the fundi were normal. The patient was advised of these findings, but he said that he could not tolerate the lenses and requested an exchange, preferably with an accommodative lens. Subsequently, he underwent uncomplicated lens exchange (Figures 1a, b, c, d), with implantation of a 17 D eyeonics crystalens in the left eye and a 16.5 D crystalens lens in the right eye.
Postoperatively, symptoms of glare and visual disability were resolved.
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Images: Brown DC |
Case 2
A 65-year-old retired man, an active golfer and a fitness enthusiast, complained of difficulty with vision related to cataracts. History included bilateral LASIK with monovision. Preoperative refraction was –1.25 + 0.25 × 160 = 20/40 in the right eye and +0.25 × 45 = 20/30 in the left.
Slit-lamp exam showed evidence of previous LASIK with a well-healed corneal flap in each eye and no interface changes. There were nuclear sclerotic and posterior subcapsular cataractous elements in each lens. The remainder of the eye exam was normal.
The patient requested cataract surgery with presbyopic correction. He had been interested in both the crystalens and the Advanced Medical Optics ReZoom multifocal lens. After a thorough informed consent, the patient elected to have a ReZoom lens placed in his right eye and a crystalens in the left.
Each cataract extraction with lens implantation was accomplished without complication. Postoperatively, the patient complained of blurred vision, double vision, and starburst and halos at night in the right eye. Additionally, at near, letters with the right eye appeared double.
After more than 2 months, the patient said he was totally dissatisfied with the right eye due to “intolerable glare.” He also said that he wished a lens exchange, even if a monofocal implant was used.
The patient was offered a lens exchange. He was told that an attempt would be made to replace the multifocal with a crystalens, but if this was not possible the lens would be exchanged for a monofocal lens.
Lens exchange was accomplished (Figures 2a, b, c, d), and the crystalens was placed in the capsular bag with good contraction and positioning. Postoperatively, visual symptoms were relieved and he is now essentially independent of spectacles.
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Images: Brown DC |
Case 3
A 63-year-old retired physician and active outdoorsman who enjoys skiing, golf and tennis developed symptoms of bilateral cataracts with visual function impairment.
Examination revealed vision to be 20/40 in the right eye and 20/30 in the left eye with best correction. Under glare conditions, the visual acuity dropped to 20/200 in the right eye and 20/100 in the left eye.
The eye exam was normal except for the presence of lenticular opacities. The patient had been an active medical practitioner until his recent retirement, and he easily understood the lens replacement options.
He elected to undergo a combination of crystalens in one eye and the ReSTOR in the other, with the hope of maximizing his near vision while preserving good intermediate and distance vision.
Successful crystalens implantation was performed in his right eye, with 20/20 acuity at distance without correction postoperatively. Near acuity was J3 without correction.
He underwent uncomplicated cataract extraction and implantation of a ReSTOR lens in the capsular bag of the left eye. The ReSTOR lens eye was prepared as a normal implantation with a 5-mm capsulorrhexis of equal symmetry to the crystalens eye.
At 1 month postop, the patient complained that he could not tolerate the glare and blurred vision in the ReSTOR eye. He did not feel that he would be able to adjust, no matter how long the period was, and he noted additional subtle differences in the lack of clarity of the ReSTOR eye, although he measured 20/20 distance, J2 near without correction in that eye.
At this time a lens replacement was performed, removing the ReSTOR lens and replacing it with a crystalens in the capsular bag.
His symptoms were immediately relieved, and the postoperative course was uneventful.
Patient selection
There are steps that one can take to avoid the issues of dysphotopsia, glare and unsettling visual phenomena with presbyopia-correcting lens options. First is patient selection, which should include a thorough assessment of the patient’s lifestyle, ability to adjust and personality.
After you and the patient decide on the appropriate presbyopia-correcting lens option, surgery should be performed so that the eye can undergo lens exchange if the patient is unable to accept the outcome. This should include preparing the eye with a perfect curvilinear capsulorrhexis of about 5 mm in diameter. The integrity of the capsule must be preserved.
Lens removal
My technique for removing an acrylic lens such as the ReSTOR is to inject viscoelastic beneath the lens optic and use the viscous substance to dissect the lens away from the capsule. The capsule tends to form fibrous tissue relatively quickly on the acrylic material, and consequently, patience must be observed to slowly extract the lens from the capsular bag. Once the capsule has been separated, a Kuglen hook or other similar instrument can be used to stabilize the capsule, providing counter-traction as the lens haptics are dialed out of the capsule and into the anterior chamber with a second instrument.
The corneal incision is large enough to remove the IOL without cutting it. This also facilitates implantation of the crystalens, which can be inserted flat and placed into the capsular bag.
A similar technique can be used for the ReZoom lens, although the haptics of that lens are not as broad as those of the ReSTOR.
If lens replacement with the crystalens is impossible due to the capsular fibrosis, the surgeon must be sure that the patient is willing to accept a monofocal lens implant in the ciliary sulcus, or he may even brave an attempt at sulcus implantation of a multifocal IOL of another design.
For more information:
- David C. Brown, MD, FACS, is the president and medical director of Eye Centers of Florida. Dr. Brown can be reached at Eye Centers of Florida, 4101 Evans Ave., Fort Myers, FL 33901; 239-939-3456, fax: 239-939-1575; e-mail: David.Brown@ecof.com. Dr. Brown has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.