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Numerous options available for patients with cataract in one eye
Clinical Challenge posed the following question to a panel of experts:A 59-year-old white man presents for evaluation of symptomatic visual blur in the left eye. Your examination findings are entirely normal with the exception of a moderately advanced nuclear sclerotic cataract in the left eye, but only trace nuclear sclerosis in the right eye. Best-corrected visual acuity is –5.00 sph = 20/20– in the right eye and –5.50 sph = 20/60 in the left eye. The patient would like to proceed with phacoemulsification with an IOL in the left eye. Given the asymmetry of this patient’s presentation and the potential for an extended intraocular surgical interval, how would you counsel him regarding a target outcome for the left eye? Clinical Challenge Team
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Lensectomy in right eye
Thomas Chester, OD, FAAO: My recommendation would be a surgical outcome of –0.50 D sph for the left eye, provided that this patient has a lensectomy on the right eye to limit the duration of his anisometropia. We aim for –0.50 D sph in the left eye to allow for healing variations, which can result in an outcome anywhere from plano to –1.00 D sph, and to reduce the probability of leaving the patient a hyperope.
A prescription within this range best meets the needs of both distance and near activities of a non-dominant eye. Conversely, the target for the right eye should be plano. Careful postoperative observation of the left eye’s healing process and outcome will guide our calculation of the IOL used for the right eye. Being the better functioning of the two eyes, the patient has been using it for distance activities such as driving, and, as a result, maximum distance vision should be preserved.
The visual outcome of the surgery will be slight monovision, allowing the patient to maintain excellent distance vision as well as very good functional near vision. Because the right eye has a best-corrected visual acuity of 20/20–, the surgery would be considered a clear lensectomy rather than a cataract surgery in the traditional sense. Because the patient lacks accommodative ability in either eye, he will not be harmed by the removal of a non-accommodating lens.
Another option would be to forgo the lensectomy in the right eye for LASIK. This achieves a similar refractive outcome, but modifies the cornea, possibly making future cataract surgery calculations more difficult, a viable concern for an older patient. If the patient refuses surgery altogether in the right eye, he could be corrected with a contact lens. However, because a clear lensectomy prevents the need for future cataract surgery, I believe this route presents the best overall outcome for the patient.
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Evaluate right eye options
Deepak Gupta, OD: Before deciding on what refractive error to aim for when operating on the left eye, you should see what options are available for the right eye. Most patients will not tolerate a 5.00 D difference between the two eyes, so shooting for anything around plano for the left eye will not work unless you can fit the patient with a contact lens in the right eye.
If you can do this, then you can shoot for plano (or –0.50 D as most surgeons do). You should do this fit before the cataract surgery in the left eye to make sure it will work. If the patient is contact lens intolerant in the right eye, then you will want to shoot for about –3.00 D. By doing this, you have still lowered the patient’s refractive error, but you kept the difference between the two eyes to less than 3.0 D (the maximum amount most patients can tolerate). Years later, when the right eye is done, then that eye can be reduced to –1.00 D or so.
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Offer four options
Maynard L. Pohl, OD, FAAO: My approach is to offer the patient four options. The first is cataract extraction in the left eye with a target refractive outcome of emmetropia, with the understanding that spectacle wear for distance vision in the right eye postoperatively likely would not be tolerated and that contact lens wear in the right eye would be needed postoperatively to balance vision until future cataract extraction in the right eye. The second option is refractive lensectomy in the right eye, following uncomplicated cataract surgery in the left eye and pending retinal stability in the right eye, rather than contact lens wear in the right eye. The third is cataract extraction in the left eye with a target refractive outcome of between –3.00 sph and –5.00 sph, with the understanding that spectacle wear would be possible and required for distance vision but that the prevailing nearsightedness still would allow for “removing the sliver” or “shaving up close” or “reading in bed” without glasses. A fourth option could be emmetropia in the left eye with corneal reshaping to achieve emmetropia in the right eye, although this would not be my recommendation given the potential for perceptive differences in vision between the eyes with this degree of prescription.
Essentially, the patient would have to decide following a comprehensive discussion of the pros and cons of each option and should be encouraged to choose the option most compatible with his or her lifestyle. This discussion should be documented in the patient record to help avoid potential misunderstandings following surgery.
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Check old records
Chris Quinn, OD: The first step is to see if any old records are available to determine what the patient’s previous refractions were. Despite the clinical description of “trace NS” in the right eye, I’d be suspicious that there in fact is a substantial nuclear cataract in the right eye. If old records show a significant myopic shift in both eyes, then I would be even more suspicious that there is a significant cataract in the right eye.
Many patients with nuclear cataracts and a myopic shift can achieve good visual acuity but have very poor qualitative vision. These patients who undergo cataract surgery in the “bad” eye invariable want surgery in the fellow eye when they realize how poor the quality of vision is in the unoperated eye. In such a case, removing the cataract in the right eye despite measured visual acuity of 20/20– should be a consideration. If old records indicate a significant myopic shift in both eyes, the patient should be carefully counseled about his options.
Option #1: Aim for plano in the left eye with the expectation that the patient will want the cataract removed from the right eye after the left eye.
Option #2: Aim for plano in the left eye, and wear a contact lens in the right eye until surgery is needed in the right eye.
If old records are not available or show no long-term change in refractive error, the patient should again be counseled regarding his options. My order of preference would be:
Option #1: Aim for plano in the left eye and have LASIK in the right eye.
Option #2: Aim for –3.00 in the left eye. Patient would require distance and reading glasses with a small risk of symptoms related to anisometropia. Additionally, the patient would have usable near vision in the left eye without correction.
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