- Email: [email protected]
Cataract surgical problem
CONSULTATION SECTION
I would not recommend surgery but rather fit a rigid contact lens. MICHAEL C. KNORZ, MD Mannheim, Germany
- This patient had moderately high myopic astigmatism, large pupils, and poor BSCVA before surgery. He had a large-zone treatment and now, although acuity is better, has severe problems in dim illumination. An aberrometry-based retreatment was performed in the left eye and resulted in some improvement, but not enough. The primary treatment was performed using a Nidek system, one with which I am not familiar. The platform used to perform the wavefront enhancement was not mentioned. There are a few unanswered questions. We can speculate (which is all we can do with the limited information provided) the poor BSCVA preoperatively could have been caused by underlying visually destructive aberrations. It would be useful to know whether the patient had night-vision issues preoperatively. Preoperative wavefront maps should be obtained for eyes with large pupils, especially if the BSCVA is reduced. A regular treatment of large magnitude was performed. This induced more aberration, which from the maps appears to be spherical. The other issue to bear in mind is that the residual stroma under the flap may not allow further enhancement by LASIK. By calculation from the data provided, the residual stromal bed in the right eye is 291 mm and in the left eye 303 mm after the first treatment and 279 mm after the enhancement. I would evaluate the patient’s eyes using Orbscan and Zywave (Bausch & Lomb). A trial of contact lenses can be attempted; however, based on the level of aberration, this is unlikely to be of benefit. The other alternative is to perform a wavefront enhancement by LASIK (flap lift) or surface ablation. Surface ablation on a previous flap can result in haze; however, some advocate the use of mitomycin-C (MMC) after ablation to avoid this. My preference is to avoid surface ablation and MMC as the long-term effects are unknown. I would perform a wavefront LASIK enhancement using a flap lift and the Bausch & Lomb platform. I have had moderate experience dealing with retreatments using Zyoptix wavefront treatments (‘‘Evaluation of Zyoptix LASIK to Correct Undesirable Visual Symptoms After Previous 1278
Refractive Surgery,’’ presented at the ASCRS Symposium on Cataract, IOL and Refractive Surgery, Washington, D.C., USA, April 2004, and the 8th ESCRS Winter Refractive Surgery Meeting, Barcelona, Spain, January 2004). Correlation of the Orbscan elevation map and the qualitative high-order aberrometry map is very useful in assessing whether a wavefront treatment is likely to be of benefit. For instance, if there are a high magnitude of spherical aberration and a rim of peripheral elevation on Orbscan, the likelihood of a successful enhancement is high. The magnitude of correction will have to be assessed, bearing in mind that correction of spherical aberration results in a myopic shift that needs to be compensated for by central ablation. Because of the magnitude of spherical aberration in this case and the limited residual stroma available, the patient would need to be counseled carefully. He should be told that although quality of vision may improve, he could become more myopic and would probably have to depend on optical correction. That the patient is receiving psychiatric help and is on antidepressants is a concern for 2 reasons: (1) Tricyclic antidepressants can increase pupil size, so it is best to check that patients are not taking these agents; (2) clinically depressed individuals are rarely satisfied, even with documented objective improvement. It would make sense to communicate closely with the patient’s psychiatrist in advance of treatment to ensure that it is truly his vision that is causing the patient a problem rather than something else. This case illustrates the need to obtain a wavefront aberration for all patients who have large pupils, and certainly in those who have reduced BSCVA, and to consider a wavefront treatment to, at the least, reduce preexisting aberrations. Also, careful counseling of patients with large pupils and high magnitude of correction about the risk for night-vision problems is vital. Technology has its limitations, and treating an optical zone matching scotopic pupil size does not necessarily avoid induction of visually destructive aberrations. SHERAZ DAYA, MD, FACP, FACS London, United Kingdom
Editor’s note: The author is an unpaid consultant to Bausch & Lomb and receives reimbursement for travel expenses to meetings.
J CATARACT REFRACT SURG—VOL 31, JULY 2005
I would not recommend surgery but rather fit a rigid contact lens. MICHAEL C. KNORZ, MD Mannheim, Germany
- This patient had moderately high myopic astigmatism, large pupils, and poor BSCVA before surgery. He had a large-zone treatment and now, although acuity is better, has severe problems in dim illumination. An aberrometry-based retreatment was performed in the left eye and resulted in some improvement, but not enough. The primary treatment was performed using a Nidek system, one with which I am not familiar. The platform used to perform the wavefront enhancement was not mentioned. There are a few unanswered questions. We can speculate (which is all we can do with the limited information provided) the poor BSCVA preoperatively could have been caused by underlying visually destructive aberrations. It would be useful to know whether the patient had night-vision issues preoperatively. Preoperative wavefront maps should be obtained for eyes with large pupils, especially if the BSCVA is reduced. A regular treatment of large magnitude was performed. This induced more aberration, which from the maps appears to be spherical. The other issue to bear in mind is that the residual stroma under the flap may not allow further enhancement by LASIK. By calculation from the data provided, the residual stromal bed in the right eye is 291 mm and in the left eye 303 mm after the first treatment and 279 mm after the enhancement. I would evaluate the patient’s eyes using Orbscan and Zywave (Bausch & Lomb). A trial of contact lenses can be attempted; however, based on the level of aberration, this is unlikely to be of benefit. The other alternative is to perform a wavefront enhancement by LASIK (flap lift) or surface ablation. Surface ablation on a previous flap can result in haze; however, some advocate the use of mitomycin-C (MMC) after ablation to avoid this. My preference is to avoid surface ablation and MMC as the long-term effects are unknown. I would perform a wavefront LASIK enhancement using a flap lift and the Bausch & Lomb platform. I have had moderate experience dealing with retreatments using Zyoptix wavefront treatments (‘‘Evaluation of Zyoptix LASIK to Correct Undesirable Visual Symptoms After Previous 1278
Refractive Surgery,’’ presented at the ASCRS Symposium on Cataract, IOL and Refractive Surgery, Washington, D.C., USA, April 2004, and the 8th ESCRS Winter Refractive Surgery Meeting, Barcelona, Spain, January 2004). Correlation of the Orbscan elevation map and the qualitative high-order aberrometry map is very useful in assessing whether a wavefront treatment is likely to be of benefit. For instance, if there are a high magnitude of spherical aberration and a rim of peripheral elevation on Orbscan, the likelihood of a successful enhancement is high. The magnitude of correction will have to be assessed, bearing in mind that correction of spherical aberration results in a myopic shift that needs to be compensated for by central ablation. Because of the magnitude of spherical aberration in this case and the limited residual stroma available, the patient would need to be counseled carefully. He should be told that although quality of vision may improve, he could become more myopic and would probably have to depend on optical correction. That the patient is receiving psychiatric help and is on antidepressants is a concern for 2 reasons: (1) Tricyclic antidepressants can increase pupil size, so it is best to check that patients are not taking these agents; (2) clinically depressed individuals are rarely satisfied, even with documented objective improvement. It would make sense to communicate closely with the patient’s psychiatrist in advance of treatment to ensure that it is truly his vision that is causing the patient a problem rather than something else. This case illustrates the need to obtain a wavefront aberration for all patients who have large pupils, and certainly in those who have reduced BSCVA, and to consider a wavefront treatment to, at the least, reduce preexisting aberrations. Also, careful counseling of patients with large pupils and high magnitude of correction about the risk for night-vision problems is vital. Technology has its limitations, and treating an optical zone matching scotopic pupil size does not necessarily avoid induction of visually destructive aberrations. SHERAZ DAYA, MD, FACP, FACS London, United Kingdom
Editor’s note: The author is an unpaid consultant to Bausch & Lomb and receives reimbursement for travel expenses to meetings.
J CATARACT REFRACT SURG—VOL 31, JULY 2005