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Cataract Surgery | Apr 2013

Evaluate This: Surgeon-Submitted Case Presentations

A panel of refractive surgery experts proposes treatment plans for a variety of cases.

For the cover focus on decision-making in refractive surgery in this issue, we asked CRST Europe Editorial Advisory Board members to submit challenging cases, and we then invited an international panel of refractive surgeons to respond with their best suggestions for managing these patients’ visual complaints. The results below demonstrate the broad range of options currently available to refractive surgeons worldwide.

SUPHI TANERI, MD

This is a case of a small myopic shift after LASIK performed 6 years earlier in a presbyopic patient. The interesting feature is a meridional thickening of the epithelium of the left eye, which may play a role in the patient’s present refraction.

I would try to validate this epithelial hyperplasia with another diagnostic tool such as anterior segment optical coherence tomography (OCT). If both methods were in agreement, then I would inform the patient about the decreased predictability of any further corneal ablation procedure due to her epithelium. The source of the epithelial thickening may be some epithelial basement membrane dystrophy, which could change the epithelial thickness over time, leading to slowly fluctuating refraction and vision. A discussion about the risks and benefits of a corneal abrasion alone or in combination with phototherapeutic laser ablation would follow.

Another cause of the epithelial thickening could be masking of a beginning ectatic cone. The Pentacam (Oculus Optikgeräte GmbH) maps shown are not quite suggestive of that scenario, but they should nevertheless be compared with the early postoperative measurements to rule out the possibility, which would necessitate corneal collagen crosslinking (CXL).

ROBERT EDWARD T. ANG, MD

First, I would ask this patient how happy she is with her current distance vision and reading vision. Second, I would measure her monocular and binocular uncorrected distance, intermediate, and near vision. Then I would do a trial lens fitting to simulate both eyes corrected for 20/20 distance, one eye corrected for 20/20 distance, and no correction to see which of these three options she would prefer.

Although 6 years ago her priority was good far vision, now that she is presbyopic, it does not hurt to ask if her thoughts on the matter have changed. Currently, she presents with a monovision effect, which may be functional for her. Performing a trial lens simulation of treatment of one eye or both eyes will give her an idea of how to decide.

If she opts for good distance vision, I would perform anterior segment OCT (Visante OCT; Carl Zeiss Meditec) to check the flap and residual bed thickness. If the stromal bed was adequate, I would perform enhancement LASIK by lifting the flap on the dominant eye first. I would then observe and, after 1 to 2 weeks, ask the patient if the improvement in distance vision is acceptable with some reading vision in the fellow eye. Only if she signified she was willing to wear reading glasses all the time would I enhance the second eye.

If the Visante OCT showed a residual bed thickness of less than 300 μm, I would advise the patient to wear glasses for driving or other distance vision activities. I prefer not to perform PRK over a flap for fear of scarring or increased eye pressure caused by prolonged exposure to topical steroids.

DETLEF HOLLAND, MD

With a 120-μm flap, lifting the flap after 5 years should not be a problem, so a retreatment for the myopic astigmatism in both eyes would be acceptable. On the other hand, if the remaining stromal bed was less than 300 μm, we would also consider a transepithelial PRK in our clinic. We would recommend CXL because the map of the right eye shows a slight sign of inferior steepening. I would also recommend a contact lens test with correction of the dominant eye. Perhaps the patient would benefit from monovision at her age and in the future when her presbyopia increases.

DIEGO DE ORTUETA, MD, FEBO

My first option would be to relift the flap if there was adequate stromal thickness. We know that a 120-μm flap was created with the IntraLase. For security, I would calculate the flap thickness as 120 μm plus two standard deviations; the calculated flap would be about 140 μm. Knowing that the stromal thickness for both eyes is 438 μm, which is enough to correct a refractive error of about -1.50 D and have residual stromal thickness of more than 275 μm, we can proceed with LASIK enhancement.

However, in this case, the posterior map shows a difference of 60 μm, and the epithelium is irregular in the left eye. The patient is 45 years old, and the sagittal map of the topography does not show any signs of keratectasia, so I would relift the flap, at least in the right eye, using the same optical zone as in the first surgery. I would perform a corneal wavefront-guided ablation only if there were significant corneal aberrations, such as positive spherical aberration of 0.3 μm or more with a 6-mm pupil.

Because the left eye has an irregular epithelium, I would measure it again another day to see if the same map would be produced. If so, I would prefer to perform surface ablation. In case of a retreatment with an irregular epithelium, I aim to smooth the epithelium and also treat the refractive error. Therefore, I would use transepithelial PRK, in which the epithelium is ablated with an aspheric phototherapeutic keratectomy (PTK) mode, with more ablation at the periphery than at the center, in addition to PRK. The epithelial thickness ablation should cover at least the thickest point of epithelium, to achieve a smooth surface on which the new epithelium can grow. I would increase the epithelial thickness on the Amaris laser software (Schwind eye-techsolutions) from 55 μm in the center to 70 μm to be sure to ablate all of the epithelium. As we perform a surface ablation over the flap, I would use mitomycin C to prevent haze.

JODHBIR S. MEHTA, MD

This 45-year-old presbyopic woman has had LASIK in her late 30s. She now presents with regression in both eyes. Due to her current age, after checking her eye dominance, I would first establish whether she wanted to have any treatment because she already has a monovision correction at the moment. She may well be happy with her current refractive error. If she really wants better distance vision and accepts the fact she will have to wear glasses for near vision, I would first need to establish that the refraction is stable. I would repeat the refraction at least 4 to 6 months following this consultation to ensure stability. If it is stable, the decision for treatment would be dependent on the residual stromal bed. Although her LASIK was performed with the FS60, there is a standard deviation to the flap thickness. Taking into account epithelial thickening, even in the event of a perfectly created 120-μm flap, the residual stromal bed would be 250 μm. In view of that, if the patient insisted on treatment I would offer PRK with adjunctive mitomycin C (MMC), and I would counsel her preoperatively regarding the possible reduction in contrast sensitivity after treatment.

DR. TANERI

This patient has insufficient visual acuity due to irregular astigmatism and subepithelial scarring as a residue of her bullous keratopathy. Because the scarring does not look too dense in the central cornea in the slit-lamp photo, I would recommend a rigid gas-permeable (RGP) contact lens trial. This way, the effect of the irregular astigmatism could be compensated for. If the patient was happy with these contact lenses, I would not push for surgery. However, not many 67-year-olds tolerate contact lenses well. If that is the case, I would recommend a wavefront- or topography-guided ablation (depending on the laser platform available) to minimize both the irregular astigmatism and the subepithelial scarring. A full-thickness corneal transplant would be my last resort.

DR. ANG

This patient’s poor vision may be due to a combination of corneal haze and irregular astigmatism. I would try to fit her with either soft or RGP contact lenses to see if her vision improves. If so, I would advise her to wear the most comfortable contact lenses that fit and then regularly monitor her.

I would probably not perform any surgical intervention, especially if the fellow eye sees well. The only possible surgery I might consider doing is a wavefront-guided PRK with MMC to lessen the irregular astigmatism and remove some of the haze if it is truly subepithelial. At this point, doing less is probably the more prudent approach.

DR. HOLLAND

The patient’s thick cornea indicates that laser refractive surgery would be a good option. Because of the corneal irregularity and the subepithelial scarring, I would recommend transepithelial PRK based on corneal wavefront analysis with intraoperative MMC application.

DR. DE ORTUETA

This is an aberrated eye with refractive error, irregular epithelium, and some subepithelial scars. Because the patient has previously undergone corneal surgery, most aberrations in this eye will likely be corneal. With topography, we probably get a reliable measurement and can therefore at least diminish the aberrations. I would perform transepithelial PRK. The primary advantage of this is that we treat what we see, as the topography measures the surface and therefore the epithelium that is masking the stroma. I would also inform the patient that a second treatment may be necessary. With a second surface ablation, we have the advantage that the subepithelial scars will no longer be there, as they will likely have been ablated with the first ablation. The difficulty in treating higher- and lower-order aberrations, as in this case, is that the higher-order aberrations also affect the lowerorder aberrations of sphere and cylinder, and, although this is accounted for by our software, it is not always easy to calculate.

DR. MEHTA

This patient has irregular surface astigmatism following DSAEK. To be certain there is no irregularity from the DSAEK, not only is documentation of the central graft thickness important but also the ratio of the central to peripheral graft thickness, as a steep posterior meniscus curve can induce a hyperopic shift. Therefore, I would first ascertain this. I presume that any sutures have been removed as well. If the visual deficit was from irregular surface astigmatism, I would then perform a trial with RGP contact lens over-refraction to establish whether there is improvement in the visual acuity. Potential acuity meter measurement may also be useful. If there was improvement with over-refraction, the next thing to ascertain would be the depth of the scarring. If the subepithelial scarring was mainly superficial, I would consider a topography-guided PRK with MMC. If it was deeper, I would consider a hemi-automated lamellar keratoplasty.

DR. TANERI

Generally, I would not surgically treat an emmetropic patient with perfect unaided distance vision because of medicolegal issues that may differ from country to country. First, even if only one eye was made myopic (-1.75 D), then, in Germany, the patient would legally be obliged to wear spectacles while driving. Second, many German ophthalmologists would consider it unethical to operate on an emmetropic eye. So, in this case, if the patient was not 100% happy after the procedure, a surgeon would have a hard time defending himself or herself.

Moreover, in this particular case, the topography and tomography maps reveal an inferior steepening of the cornea that is suggestive of mild forme fruste keratoconus. This inferior steepening is probably stable and may actually be helpful for uncorrected near and intermediate vision. I would recommend waiting for lens opacification to commence before performing refractive lens exchange with multifocal IOLs.

DR. ANG

The patient is emmetropic in both eyes, with mild hyperopia and cylinder in the right nondominant eye. She already underwent a monovision trial and was happy with the results, even with the compromise in distance vision. Her topography and corneal thickness seem to be within normal limits, making her a good candidate for a corneal presbyopia procedure.

My first choice would be to perform Supracor presbyopic LASIK on the right eye. With this treatment, we target a postoperative refraction of -0.50 D. Most patients would achieve 20/25 distance UCVA, 20/25 intermediate UCVA, and J1 near vision.

Another good option for this patient is combined LASIK and Kamra intrastromal corneal inlay (AcuFocus) implantation. I would create a thick flap, perform hyperopic LASIK to target -0.75 D, and place the inlay. Most patients would achieve 20/20 distance UCVA, 20/25 intermediate UCVA, and J2 near vision. Refractive targeting is crucial for both procedures and can be customized depending on the lifestyle of the patient. Aiming for a more myopic outcome yields better near vision but entails some decrease in distance UCVA.

In my experience, more Supracor patients than Kamra inlay patients achieve J1 near vision, but there is a corresponding decrease of distance vision, with most patients having 20/30 distance UCVA. Kamra inlay patients achieve about J2 to J3 but retain good distance vision of 20/20, despite a myopic refraction. With both treatments, it is important to discuss unwanted photic phenomenon such as glare, halos, and decreased contrast vision. Managing patient expectations is crucial.

DR. HOLLAND

Because the patient was happy with monovision, she would likely be happy with monovision in future as well. Her dominant eye is near emmetropic, so I would suggest hyperopic LASIK targeting -1.75 to -2.00 D. The patient should be informed that long periods of reading in the future will require the use of a reading add. Because of the posterior elevation in the right eye seen on the map, intraoperative CXL may be discussed with the patient. The diagnostic images should be repeated because the quality is not perfect (missing rings superiorly and nasally in both eyes).

DR. DE ORTUETA

To create monovison surgically in a patient who has already used the monovision strategy with contact lens correction is a good option. However, this patient’s cornea has a high preoperative keratometry (K) value (45.91 D), which can lead to problems with dry eye and postoperative aberrations. If we treat the 2.00 D to achieve monovision, the predicted postoperative K for the right eye would be about 47.70 D; my limit is around 48.00 D. The problem is that both eyes show asymmetry between the superior and inferior parts of the cornea, which, again, can cause aberrations. Knowing that, I would not perform LASIK in this case.

A phakic IOL such as the Visian ICL (STAAR Surgical) is a good option if the patient has a deep anterior chamber. As long as the patient has some accommodation, I would prefer this option to a refractive lens exchange.

Dr. MEHTA

This 53-year-old woman is keen on presbyopic treatment to provide her with a monovision correction. Despite her age, she seems to tolerate this well with contact lens correction. Her topography scans show high posterior floats in both eyes. There is also inferior steepening on the sagittal curvature in both eyes, although it is more prominent in the left eye than in the right. Due to her age, her risk of ectasia is lower than that of someone in her 20s, but I would still like to examine the progressive thickness map on the Pentacam. In view of the suspicious curvature, I would offer advanced surface ablation.

DR. TANERI

In this presbyopic patient, I would re-treat only the right eye due to the reasons outlined in my response to Case No. 3. In order to avoid potential problems when lifting a flap that was created 5 years earlier (eg, epithelial ingrowth), I would perform an ablation on the flap. This patient is especially bothered by his reduced near vision; therefore, I would discuss a varifocal ablation pattern with him to increase his depth of field. Again, I would recommend waiting for lens opacities to show before proposing a lens exchange with multifocal IOLs.

DR. ANG

It is not unusual to see patients such as this with regression after hyperopic LASIK. For this patient, I would perform a refractive enhancement to target plano in his right eye by correcting approximately 1.25 D, not just 0.75 D, to improve his distance vision to close to 20/20. For his left eye, I would perform an enhancement using the Supracor presbyopic algorithm to target -0.75 D to improve his near vision to J1 and his distance vision to 6/9 to 6/12.

DR. HOLLAND

First, I would repeat the images because of their poor quality (missing rings). This is important because the left eye shows superior steepening. If the second examination shows the same result, intraoperative CXL is recommended. At 5 years after the original LASIK, I would recommend retreatment by lifting the flap and performing a hyperopic ablation profile in both eyes, targeting plano in the right eye and 1.75 D in the left eye.

DR. DE ORTUETA

In this case, hyperopic LASIK in a 50-year-old man shows some regression after 4 to 5 years. The cornea looks normal, the K reading is about 44.00 D, and with the refraction of +0.75 D the patient is happy. I would perform a LASIK enhancement in both eyes after relifting the flap. With the negative spherical aberrations induced, we are also giving the patient greater depth of focus. Good centration is important, although the correction is not very high. I would use the same optical zone and centration as was used in 2008. If I cannot decide where to center, I would use the corneal vertex to preserve the geometric point, with an optical zone of at least 6.5 mm.

DR. MEHTA

This 50-year-old man underwent hyperopic LASIK in 2008. He has regression in both eyes and now requires +0.75 D correction. Again, I would first need to establish that his refraction is stable and hence would require two readings at least 4 to 6 months apart. We would also need to establish the flap thickness of whichever machine was used, so a high-resolution OCT image of the cornea would be useful. If the RTVue (Optovue Inc.) is unable to delineate the flap, then an intraoperative flap lift and pachymetry measurement may be used for confirmation. The posterior floats on the topography are normal. If the residual stromal bed allowed, I would offer LASIK in combination with highspeed CXL to try to obtain more stability.

DR. TANERI

Epithelial ingrowth has become a rare complication after primary LASIK. However, it does occur in a small percentage of patients after relifting a flap, as in this case. Luckily, the ingrowth has not yet affected the patient’s central vision. I would show the patient the distorted rings on her topography exam and explain the deleterious optical effects they will have on her vision once the cells reach further centrally.

If these ingrowing cells are isolated, ie, not in contact with the flap margin (which can only be determined at the slit lamp), I would wait and follow up closely because, ultimately, the ingrowth should resolve spontaneously. If, however, there were a supplement of new epithelial cells from the flap margin, I would advise immediate treatment despite her good UCVA of 20/20. My strategy would be to remove a 1-mm–wide strip of epithelium just outside the flap gutter at the affected corneal sector to prevent recurrence. Next, I would partially lift the flap over the ingrown area. Then I would apply distilled water, which is hypotonic, to loosen the epithelial cells before scraping both the stroma and the underside of the flap. After irrigation, I would put the then-edematous flap back and massage intensively to ensure proper adhesion. I would apply a bandage contact lens and examine the patient the next day.

I would not use alcohol or other agents such as MMC because their effect in these cases is not known. Another appealing option would be to use an Nd:YAG laser to destroy the cells in the interface without needing to relift the flap.

DR. ANG

Under slit-lamp visualization, I would place ink marks on the cornea to delineate the area of ingrowth. Then I would carefully lift the flap and clean the interface and back side of the flap, taking care to lift only the area of ingrowth and hopefully not to encroach on the visual axis to preserve the patient’s good distance vision. I would then swab the bed with a sponge soaked in 20% alcohol to prevent recurrence of the ingrowth. After drying the flap, I would place a bandage contact lens and remove the lens after 1 week.

DR. HOLLAND

If I were seeing this patient for the first time, photodocumentation would be performed, as would a follow-up visit after 4 weeks for comparison. With 20/20 vision, lifting the flap and cleaning the stromal bed and posterior surface of the flap are always a challenge. If the ingrowth and irregularity of the corneal topography were increasing, a treatment of the ingrowth would absolutely be necessary.

DR. DE ORTUETA

In this case, we have the problem of epithelial ingrowth in an eye that underwent a LASIK enhancement 6 months previous. The patient has a good UCVA and no known visual disturbances. I would observe to see what happens after 4 to 6 months and whether the epithelium continues to grow or not. The problem is that, if corneal melting occurs, that would cause a peripheral scar.

If we relift the flap and clean the stroma of the epithelial cells, I would inform the patient of the possibility of epithelial regrowth. If this occurs, the only options to prevent the epithelium from growing again are to place a suture or use fibrin glue; however, aberrations could be induced in both cases. So, again, because the patient is happy, I would observe the epithelium and treat the patient only if the epithelial island grows.

DR. MEHTA

This patient underwent primary LASIK followed by an enhancement. Following this, she had epithelial ingrowth, which can occur quite frequently after flap relifts. There is minimal refractive change, and the keratometric rings show some early changes. In view of her visual acuity and minimal refractive changes, I would photograph the epithelial ingrowth and observe the patient. In the future, if there were progression and changes in the patient’s refraction and keratometry, I would then offer a flap lift and washout with counseling about possible recurrence. I would also advise the patient to come back earlier if any inflammation or blurred vision occurred. Nd:YAG laser has also been used to eliminate epithelial ingrowth, and this may be an option if treatment is needed.

DR. TANERI

I would try to treat the nighttime glare of this young trauma patient conservatively by recommending application of brimonidine tartrate 0.1% eye drops before dawn. This alpha-adrenergic receptor agonist is widely used in glaucoma therapy and has an interesting side effect: It prevents the pupil from widening under lowlight conditions, without constricting it as pilocarpine would. If the patient was not satisfied by this, then I would recommend a sector-shaped iris prosthesis to cover the iris defect. However, the associated risk of cataract formation must be discussed in detail with this young patient.

DR. ANG

I would first try giving this patient 0.5% pilocarpine to constrict his pupil and check whether his vision and higher-order aberrations improve. If they improve, I would probably place him on these drops for the long term. The only time I would consider doing surgery would be if unwanted side effects occurred. If pushed to do surgery, I would likely suture the torn section of the iris with polypropylene sutures.

DR. HOLLAND

In my opinion, the patient’s large pupil is the most significant problem. If we look only at the aberrations, one would suggest treatment, especially for coma, trefoil, and spherical aberrations; however, the pupil size would still be problematic.

To start, I would recommend a trial with a colored iris contact lens to see how much the patient profits from the artificial pupil. If this is not successful, pupilloplasty and treatment of the aberrations with wavefront-guided LASIK should be discussed with the patient.

DR. DE ORTUETA

The patient has an inferior ovalization of the pupil after a trauma, which creates symptoms of glare. I would perform topography and ocular aberrometry to determine the source of the aberrations. If they are corneal, we can obtain them from topography, and if they are internal, we can obtain them by subtraction of the ocular aberrations.

I would calculate the ocular aberrations from the first Purkinje reflex, for modifying the pupil contour. The advantage of this is that this reflex is nearer to the visual axis, therefore reflecting the real vision of the patient. I would present the effect of blurred vision to the patient in a graphic, as shown in the figure, and ask if he sees in a similar way. I would ask the patient whether his blurred vision is similar to ocular aberrometry centered on the pupil center or centered on the first Purkinje reflex. If the coma is still high, we should determine whether the lens is subluxated, and, if so, then potentially observe whether the patient develops a cataract.

I would discuss performing a surface ablation centered on the first Purkinje reflex or corneal vertex and would inform the patient that, if a cataract develops, we must treat the cornea again, as the aberrations may change if we perform surgery on the lens.

DR. MEHTA

This patient had trauma and now has nighttime glare. There is a high level of trefoil on the wavefront scan. It would be good to be able to differentiate corneal from lens aberrations with iTrace (Tracey Technologies, Corp.) imaging. Given the patient’s type of trauma, I would be highly suspicious of lens pathology or traumatic mydriasis of the pupil causing the underlying symptoms.

A. John Kanellopoulos, MD, is the Director of the LaserVision.gr Eye Institute in Athens, Greece, and is a Clinical Professor of Ophthalmology at New York University School of Medicine. He is an Associate Chief Medical Editor of CRST Europe and a consultant to Alcon Laboratories, Inc./WaveLight. He may be reached at tel: +30 21 07 47 27 77; e-mail: ajkmd@mac.com.

Arthur B. Cummings, MB ChB, FCS(SA), MMed (Ophth), FRCS(Edin), practices at the Wellington Eye Clinic & UPMC Beacon Hospital, Dublin, Ireland. Dr. Cummings is an Associate Chief Medical Editor of CRST Europe. He states that he is a consultant to Alcon Laboratories, Inc./WaveLight. Dr. Cummings may be reached at tel: +353 1 2930470; fax: +353 1 2935978; e-mail: abc@wellingtoneyeclinic.com.

Karl G. Stonecipher, MD, is Director of Refractive Surgery at The Laser Center in Greensboro, North Carolina. Dr. Stonecipher is a member of the CRST Europe Global Advisory Board. He states that he is a consultant to Alcon Laboratories, Inc., Allergan, Inc., Bausch + Lomb, and Nidek and serves on the medical board for LenSx. He may be reached at tel: +1 336 288 8823; e-mail: stonenc@aol.com.

Suphi Taneri, MD, is the Director of the Center for Refractive Surgery, Eye Department, St. Francis Hospital, Münster, Germany. Dr. Taneri states that he has no financial interest in the material presented in this article. He may be reached at tel: +49 251 987 7890; fax: +49 251 9877898; e-mail: taneri@refraktives-zentrum.de.?

Robert Edward T. Ang, MD, is Senior Consultant at the Asian Eye Institute in the Philippines. Dr. Ang states that he has financial interest in AcuFocus, Inc.; Allergan, Inc.; Bausch + Lomb; and Technolas Perfect Vision. He may be reached at e-mail: RTAng@asianeyeinstitute.com.

Detlef Holland, MD, is a cataract and refractive surgeon at the Augenklinik Bellevue, Kiel, Germany. Dr. Holland states that he has no financial interest in the products or companies mentioned. He may be reached at e-mail: d.holland@augenklinik-bellevue.de

Diego de Ortueta, MD, FEBO, is a Senior Consultant at the Aurelios Augenzentrum, Recklinghausen, Germany. Dr. de Ortueta states that he is a consultant to Schwind eyetech- solutions. He may be reached at e-mail: diego.de.ortueta@augenzentrum.org.

Jodhbir S. Mehta, FRCS, MRCOphth, is an Associate Professor of Ophthalmology and Head of Corneal Research at the Singapore Eye Research Institute. Dr. Mehta states that he is a consultant to Carl Zeiss Meditec and an inventor of the lenticule reimplantation patent. He may be reached at e-mail: jodmehta@gmail.com.

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