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February consultation #4
CONSULTATION SECTION
- This case is very interesting due to the 2 patient complaints; that is, negative dysphotopsia and mild residual myopia. Negative dysphotopsia is a mysterious and somewhat common complaint of patients after cataract removal. Blame has been put on everything from IOLs with a square-edged design1 to temporal incisions2; however, nothing is conclusive. Treatment options for negative dysphotopsia include watchful waiting, making sure the capsulorhexis covers the optic edge, IOL exchange, and piggyback IOLs. In this case, with residual hyperopia and negative dysphotopsia, I agree that a piggyback IOL is an excellent option. The piggyback IOL may help alleviate the negative dysphotopsia and correct the residual myopia. What is interesting is that the piggyback IOL resolved the patient’s negative dysphotopsia but led to a surprising refractive result. Given the C1.00 D of residual hyperopia and using the refractive vergence formula, a C1.50 D sulcus-placed IOL should have led to near emmetropia. Clearly, that was not the case. The UBM shows an unusually large gap between the original PC IOL and the newly placed sulcus IOL. The very anterior position of the sulcus IOL in relation to the in-the-bag IOL is what likely caused the refractive surprise by changing the ELP of both IOLs. The puzzling question is, What is holding the two IOLs apart? Whatever anatomic, physiologic, or biomechanical process is responsible for keeping them in such a position, it seems to be stable. A second, and very unusual, reason for the refractive surprise would be an incorrectly labeled IOL. In any case, the patient’s vision now is stable and safe for correction. The safest option would be to continue with glasses or contact lenses; however, the patient is highly motivated to be free of optical devices. The surgical options include removal and/or exchange of the piggyback IOL or laser refractive surgery. Given the unusual conformation of the 2 IOLs, I would be concerned that removal of the piggyback IOL may lead to an unpredictable refractive error, most likely with a return of the previous hyperopia. This will lead to an unhappy patient who is losing confidence in the surgeon. With the stability in refractive error and lack of IOL-related complications, I would favor laser refractive surgery. If the cornea is not very thin and the topography is normal, the low residual myopia could be treated with LASIK. The low level of myopia will require a small treatment zone and thus a smaller flap diameter, which will likely minimize corneal anesthesia and dry eye. If the patient has risk factors for corneal ectasia, photorefractive keratectomy (PRK) may be a better choice, although I favor LASIK over PRK in this case. The patient should have rapid improvement in vision with minimal pain. Brandon Daniel Ayers, MD Philadelphia, Pennsylvania, USA
423
REFERENCES 1. Davison JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg 2000; 26:1346–1355 2. Osher RH. Negative dysphotopsias: long-term study and possible explanation for transient symptoms. J Cataract Refract Surg 2008; 34:1699–1707
- This patient is unhappy with his surgical result because of a residual refractive error, negative dysphotopsias, and likely anisometropic asthenopia. All patients having presbyopia-correcting IOL implantation must understand that second-eye surgery should be performed soon after the first surgery to achieve good functional outcomes. Otherwise, the patient and the surgeon may find themselves in “refractive purgatory”; that is, the first eye has a suboptimal outcome and the second eye has not been operated on and has a cataract with a refractive error that is causing anisometropia. In this case, the problems in the first eye should have been dealt with much sooner than 6 months after the cataract surgery. The most important issue is the residual hyperopia (C1.00 D), which is unacceptable with a diffractive IOL. The 3 options for addressing it are a corneal refractive procedure (eg, LASIK), IOL exchange, or a piggyback IOL. In most situations, I would choose LASIK if the refractive error can be handled with a contact lens until I could perform the excimer ablation, typically 3 months after IOL surgery. In this setting, LASIK has advantages over an IOL-based procedure, including higher corrective precision, astigmatism correction, and the lack of risks associated with an additional intraocular procedure (eg, endophthalmitis, cystoid macular edema, capsule compromise, endothelial cell damage). The disadvantages of LASIK over an IOL-based procedure include less timely treatment of residual refractive error (must wait for cataract incision to heal), induction of dry eye, possible need for neodymium:YAG capsulotomy before LASIK, and alteration of natural corneal asphericity. Jin et al.1 found no significant difference in efficacy, safety, or predictability between LASIK and lens-based surgical correction of residual refractive error after cataract surgery. The cause of negative dysphotopsia is controversial but likely relates to light bouncing off the IOL edge, leaving a perceived temporal shadow. Osher2 showed that most dysphotopsia becomes less significant over time. He found that the incidence after single-piece acrylic IOL implantation was 15.2% 1 day postoperatively but decreased to 2.4% after 2 and 3 years. At 1 year, only 5 patients (7 of 250 eyes) still reported the dysphotopsia, and all were happy with their results. Here, the patient’s unhappiness likely stems primarily from the residual refractive error, not the dysphotopsia.
J CATARACT REFRACT SURG - VOL 37, FEBRUARY 2011
- This case is very interesting due to the 2 patient complaints; that is, negative dysphotopsia and mild residual myopia. Negative dysphotopsia is a mysterious and somewhat common complaint of patients after cataract removal. Blame has been put on everything from IOLs with a square-edged design1 to temporal incisions2; however, nothing is conclusive. Treatment options for negative dysphotopsia include watchful waiting, making sure the capsulorhexis covers the optic edge, IOL exchange, and piggyback IOLs. In this case, with residual hyperopia and negative dysphotopsia, I agree that a piggyback IOL is an excellent option. The piggyback IOL may help alleviate the negative dysphotopsia and correct the residual myopia. What is interesting is that the piggyback IOL resolved the patient’s negative dysphotopsia but led to a surprising refractive result. Given the C1.00 D of residual hyperopia and using the refractive vergence formula, a C1.50 D sulcus-placed IOL should have led to near emmetropia. Clearly, that was not the case. The UBM shows an unusually large gap between the original PC IOL and the newly placed sulcus IOL. The very anterior position of the sulcus IOL in relation to the in-the-bag IOL is what likely caused the refractive surprise by changing the ELP of both IOLs. The puzzling question is, What is holding the two IOLs apart? Whatever anatomic, physiologic, or biomechanical process is responsible for keeping them in such a position, it seems to be stable. A second, and very unusual, reason for the refractive surprise would be an incorrectly labeled IOL. In any case, the patient’s vision now is stable and safe for correction. The safest option would be to continue with glasses or contact lenses; however, the patient is highly motivated to be free of optical devices. The surgical options include removal and/or exchange of the piggyback IOL or laser refractive surgery. Given the unusual conformation of the 2 IOLs, I would be concerned that removal of the piggyback IOL may lead to an unpredictable refractive error, most likely with a return of the previous hyperopia. This will lead to an unhappy patient who is losing confidence in the surgeon. With the stability in refractive error and lack of IOL-related complications, I would favor laser refractive surgery. If the cornea is not very thin and the topography is normal, the low residual myopia could be treated with LASIK. The low level of myopia will require a small treatment zone and thus a smaller flap diameter, which will likely minimize corneal anesthesia and dry eye. If the patient has risk factors for corneal ectasia, photorefractive keratectomy (PRK) may be a better choice, although I favor LASIK over PRK in this case. The patient should have rapid improvement in vision with minimal pain. Brandon Daniel Ayers, MD Philadelphia, Pennsylvania, USA
423
REFERENCES 1. Davison JA. Positive and negative dysphotopsia in patients with acrylic intraocular lenses. J Cataract Refract Surg 2000; 26:1346–1355 2. Osher RH. Negative dysphotopsias: long-term study and possible explanation for transient symptoms. J Cataract Refract Surg 2008; 34:1699–1707
- This patient is unhappy with his surgical result because of a residual refractive error, negative dysphotopsias, and likely anisometropic asthenopia. All patients having presbyopia-correcting IOL implantation must understand that second-eye surgery should be performed soon after the first surgery to achieve good functional outcomes. Otherwise, the patient and the surgeon may find themselves in “refractive purgatory”; that is, the first eye has a suboptimal outcome and the second eye has not been operated on and has a cataract with a refractive error that is causing anisometropia. In this case, the problems in the first eye should have been dealt with much sooner than 6 months after the cataract surgery. The most important issue is the residual hyperopia (C1.00 D), which is unacceptable with a diffractive IOL. The 3 options for addressing it are a corneal refractive procedure (eg, LASIK), IOL exchange, or a piggyback IOL. In most situations, I would choose LASIK if the refractive error can be handled with a contact lens until I could perform the excimer ablation, typically 3 months after IOL surgery. In this setting, LASIK has advantages over an IOL-based procedure, including higher corrective precision, astigmatism correction, and the lack of risks associated with an additional intraocular procedure (eg, endophthalmitis, cystoid macular edema, capsule compromise, endothelial cell damage). The disadvantages of LASIK over an IOL-based procedure include less timely treatment of residual refractive error (must wait for cataract incision to heal), induction of dry eye, possible need for neodymium:YAG capsulotomy before LASIK, and alteration of natural corneal asphericity. Jin et al.1 found no significant difference in efficacy, safety, or predictability between LASIK and lens-based surgical correction of residual refractive error after cataract surgery. The cause of negative dysphotopsia is controversial but likely relates to light bouncing off the IOL edge, leaving a perceived temporal shadow. Osher2 showed that most dysphotopsia becomes less significant over time. He found that the incidence after single-piece acrylic IOL implantation was 15.2% 1 day postoperatively but decreased to 2.4% after 2 and 3 years. At 1 year, only 5 patients (7 of 250 eyes) still reported the dysphotopsia, and all were happy with their results. Here, the patient’s unhappiness likely stems primarily from the residual refractive error, not the dysphotopsia.
J CATARACT REFRACT SURG - VOL 37, FEBRUARY 2011