At Issue: Retinal problems after refractive surgery

At Issue posed the following questions to a panel of experts: What types of retinal problems do you encounter in patients with previous refractive surgery? What management strategies have you developed to combat these problems?

Retinal detachment complications

Albert J. Augustin, MD: Retinal problems following refractive surgery are rare events and thus mostly case observations. Among the refractive procedures, photorefractive keratectomy, LASIK and laser epithelial keratomileusis (LASEK) appear to be the safest. I have seen only a few retinal detachments following LASIK. Those patients were treated by encircling band, vitrectomy and gas tamponade. One patient could be treated by pneumatic retinopexy only.

Macular bleeding due to choroidal neovascularization in a myopic patient required r-TPA and gas treatment followed by photodynamic therapy. In another patient we saw macular bleeding due to lacquer cracks without CNV. This bleeding was successfully treated by means of r-TPA and gas.

Clear-lens extraction in myopia appears to be the procedure with the highest risk for retinal complications such as retinal detachment. This is especially true if YAG capsulotomy is performed earlier than 3 months postop. We saw several patients with such complications. The treatment was similar to the treatment of retinal detachments in other pseudophakic patients (buckling procedure and/or vitrectomy and gas tamponade).

Iris claw anterior chamber implants reduce the visibility and the treatment options if retinal complications occur. These procedures should not be performed in patients with a potential for retinal complications such as diabetes mellitus.

I also saw some patients with proliferative diabetic retinopathy and ischemic maculopathy following LASIK. According to information from the refractive surgeons, these patients suffered from background retinopathy before the procedure. The patients needed panretinal laser coagulation. There was no treatment option for the maculopathy. I personally believe that patients suffering from diabetic retinopathy should not be treated by LASIK. If refractive procedures are performed, LASEK or PRK are adequate procedures for patients with ischemic retinal disorders because they do not require suction leading to additional retinal ischemia.

Today, radial keratotomy is not performed very often. However, in our department we saw two patients with retinal detachment following RK. Vitrectomy was performed and visibility was dramatically reduced. Surgery could only be successfully completed with the use of a noncontact wide angle observation system.

Albert J. Augustin, MD, can be reached at the Department of Ophthalmology, Moltkestrasse 90, Karlsruhe 76133, Germany; +(49) 721-974-2001; fax: +(49) 721-974-2009; e-mail: 106020.560@compuserve.com.

Depends on procedure

Roberto Bellucci, MD: Let’s divide refractive surgery into two main categories: corneal surgery with the excimer laser and intraocular surgery with phakic IOLs. These two procedures usually apply to different categories of eyes with different amounts of myopia.

Before excimer laser surgery, four cases of unnoticed retinal detachment were discovered in eyes with relatively low myopia. After surgery, I saw retinal detachment as the only retinal complication. During 12 years and out of more than 3,000 surgeries performed (70% PRK and 30% LASIK), I observed six retinal detachments, two after LASIK and four after PRK. Time from surgery to detachment ranged from 2 to 11 months. In five eyes a simple buckling procedure solved the problem, but in one eye after PRK, vitrectomy and silicone oil tamponade was required. Original myopia was –13 D in this eye, too high for laser surgery according to present selection criteria. The buckling procedure always led to an increase in myopia, and in two eyes a new laser procedure was employed with success to improve the refractive outcome.

I have implanted about 100 phakic IOLs from 1997 to present. Retinal detachment with giant tears developed in three eyes soon after posterior chamber phakic IOL implantation, (ie, during the first postop month). All three eyes were highly myopic, more than –20 D, and they all required phakic IOL and lens removal, posterior vitrectomy and intraocular tamponade with silicone oil. All developed secondary glaucoma but retained useful vision, even better than preop. An additional eye developed macular hemorrhage after foldable phakic IOL implantation in the anterior chamber. This eye lost useful vision despite photodynamic therapy. This brings my figure of retinal complications after phakic IOLs to an unacceptable 4%.

Narrow selection criteria are currently applied for phakic IOL implantation, and patients are told about the increased risk of retinal complications, especially in the case of rhegmatogenous retinal detachment. I do not believe in argon or diode laser retinopexy, as 10 years ago I observed a giant tear forming along the photocoagulation border after clear lens extraction.

Roberto Bellucci, MD, can be reached at via degli Abeti 17, 25087 Salo (BS), Italy; +(39) 347-657-5001; fax: +(39) 036-543-678; e-mail: roberto.bellucci@azosp.vr.it.

Most problems myopia-related

John C. Chen, MD: Since most of the patients who undergo refractive surgery are moderate to high myopes, most of the retinal problems we see after such intervention are related to myopia. The most common problem is that of retinal detachment and retinal tears. Less commonly seen are Fuchs’ hemorrhage and macular changes secondary to degenerative myopia.

Following clear lens extraction or phakic anterior chamber IOL implantation, there may be an increased incidence of retinal tear or detachment, similar to that following cataract extraction surgery. On the other hand, for corneal refractive surgeries such as excimer or LASIK, although some of these retinal complications seem to be temporally related, I most often see them many months or years after the intervention.

Therefore, I do not think the corneal refractive surgery procedure in and of itself is a cause of these retinal problems. However, I do think a detailed retinal examination is mandatory prior to refractive surgery. I have seen cases where a subclinical retinal detachment was discovered on such routine retinal examination. Should one find lattice degeneration, or retinal breaks, I would recommend prophylactic laser photocoagulation or cryotherapy.

For rhegmatogenous retinal detachment in postrefractive surgery patients, I usually do not use a scleral buckling procedure. The induced myopia and astigmatism following scleral buckling can be quite troublesome due to anisometropia. Also, some authors have reported late flap dehiscence during scleral buckling due to surgical maneuvering of the globe. Either pneumatic retinopexy or pars plana vitrectomy is recommended, because these procedures are refraction-neutral.

Because nuclear sclerosis cataract is an almost-certain complication following pars plana vitrectomy in older patients who are already presbyopic and who have early cataracts, I often do simultaneous cataract extraction with vitrectomy. It is important to remember that the IOL power calculation should be based on the original keratometry readings.

John C. Chen, MD, can be reached at the Montreal Retina and Laser Institute, 2021 Union St., 1288 Montreal QC H3A 2S9, Canada; +(1) 514-285-8838; fax: +(1) 514-285-8897; e-mail: john.chen@mcgill.ca.

Treat according to pathology

Joseph R. Ferencz, MD: I will answer for two kinds of refractive surgery: LASIK and clear lens extraction.

I have seen several patients with symptomatic retinal tears that appeared a few weeks following LASIK. I performed laser treatment with no further complications.

I saw one patient with macular hemorrhage without CNV. It was noticed a few days following LASIK. The blood resolved spontaneously.

I treated a patient with rhegmatogenous retinal detachment without proliferative vitreoretinopathy (PVR) and macula, 1 year after LASIK. She underwent encircling buckle surgery. She had a very good anatomic and visual result following this surgery.

A patient with myopia underwent LASIK and 2 months later he had a giant retinal tear with PVR. He underwent several surgeries, including encircling buckle, vitrectomy silicon oil injection and endolaser. This patient had poor visual outcome in this eye.

A patient with bilateral clear lens extraction developed bilateral retinal detachments. In one eye, the detachment appeared a few months postop, and in the other eye it appeared a few years later. In both eyes, he underwent vitrectomy and encircling buckle. Another patient was examined by me as a second opinion. She underwent bilateral clear lens extraction for high myopia. On one of her eyes she developed vitreous hemorrhage and a large retinal tear on the next day. She underwent vitrectomy and silicone oil injection.

In conclusion, I manage the eye problem according to the type of the pathology. Previous refractive surgery does not change my management strategies.

Joseph R. Ferencz, MD, can be reached at the Meir Hospital, Department of Ophthalmology, Sapir Medical Center, Kfar Saba, Israel; +(972) 9-7672914; e-mail: ferencz@zahav.net.il.

Retinal tears can be a common risk

Hideharu Fukasaku, MD: I perform over 2,000 refractive surgery cases each year, mostly LASIK. I operate occasionally on patients with risks for retinal complications following these procedures, but I am very selective and thorough in my preop evaluations. Patients always receive extensive counseling before any refractive surgery, and follow-up is mandatory.

Perhaps the most common risk is that of retinal tears. The eye is subjected to tremendous internal forces during the application of the vacuum ring. I have measured changes in IOP of 150 mm Hg, and there must certainly be shear forces experienced across the retina as well. I always perform a careful retinal examination, and any holes or tears are prophylactically sealed to prevent detachment. In cases of lattice degeneration in which I might have taken a wait-and-see approach, I will often wall off suspect areas as a safety measure.

High myopes can experience macular degeneration in their later years. It is uncertain if refractive surgery hastens this process. I believe elevated IOP may contribute to myopic macular degeneration and, as such, I always attempt to achieve maximal lowering of IOP using timolol or latanoprost.

Diabetic retinopathy is a relative contraindication to LASIK due to the potential for vitreal hemorrhage and potential for increased macular edema. I will perform LASIK in nonproliferative diabetic retinopathy, but only after careful retinal photocoagulation, both for focal lesions and any areas of ischemia. Wound healing is also an issue in diabetic patients, and I use fibronectin obtained from the patient’s blood to aid corneal epithelial healing.

Any degree of uveitis, either anterior or posterior, is an absolute contraindication to any refractive surgical procedure. Not until the eye is completely clear for at least several months will I attempt surgery, and then I always employ extended use of anti-inflammatory agents.

Retinal vascular occlusive disease is another contraindication for LASIK. In patients with risk factors such as hypertension, lipidemia and glaucoma, I use the minimum vacuum pressure possible and ensure the shortest surgical time. It is interesting to note that I have never induced an arterial or venous occlusion with LASIK. In fact, I have used the Moria vacuum ring to elevate IOP rapidly in order to drive emboli into the distal vasculature on several cases.

Finally, glaucoma can, of course, be considered a “retinal” disease since the end state of elevated IOP is damage to the axons of the ganglion cells. I always ensure the lowest IOP prior to surgery, the lowest vacuum ring pressure possible and the shortest surgical time. It is also important to remember that, following any refractive surgery (LASIK, PRK, LASEK or RK), IOP measurement will be lower than the true IOP. Treatment goals in patients who have undergone refractive surgical procedures need to adjusted accordingly.

I would not immediately discount patients with these retinal conditions or risks, but I would advise extreme caution and diligence in their management.

Hideharu Fukasaku, MD, can be reached at the Yokohama S.T. Building 1-11-15 Kitasaiwai, Nishi-ku, Yokohama 220-0004, Japan; +(81) 45-325-0055; fax: +(81) 45-325-0054; e-mail: h-feye@po.iijnet.or.jp.

Most problems due to myopia

Zdenek J. Gregor, FRCS, FRCOphth: Patients with posterior segment problems after previous refractive surgery usually present with conditions due to their myopia, such as acute retinal detachment or CNV. Complicating factors tend to be related to impaired visualization of the posterior segment pre- and peroperatively and to the abnormal vitreoretinal relationship in relatively young individuals.

Patients who had RK tend by now to be older and not infrequently have lens opacities in addition to numerous corneal RK scars, making the preoperative assessment of the retina and the state of the vitreous difficult. The latter is particularly pertinent when deciding between a scleral buckle and vitrectomy for retinal detachment repair. A careful ultrasound examination in the surgeon’s presence may be helpful.

Photorefractive keratoplasty, as well as LASIK, may induce troublesome distortion of peripheral retinal view, and deeper-than-usual scleral indentation is required.

Retinal detachments after refractive surgery tend to be complex due to the unusual vitreoretinal relationships in a young myopic eye, such as multiple large and posteriorly placed breaks with incomplete vitreous separation. The vitrectomy approach is often required in such situations, and the use of the wide-angle viewing systems fortunately overcomes many of the difficulties experienced preoperatively.

Occasional problems with the separation of the LASIK flap have become even rarer with the noncontact viewing systems.

Patients who had previously undergone intraocular surgery such as clear lens extraction or phakic IOL implantation may develop fibrinous anterior uveitis as a result of breakdown of the blood-ocular barrier associated with their acute retinal detachment. An adequate retinal view may be difficult to obtain, even using a wide-angle system, and the removal of the IOL and/or lensectomy is required.

Zdenek J. Gregor, FRCS, FRCOphth, can be reached at Moorfields Eye Hospital, City Rd., London EC1Y2PD, England; +(44) 207-935-0777; fax: +(44) 207-935-6860; e-mail: zdenek.gregor@moorfields.nhs.uk.

Neuropathy with long suction time

Thomas Kohnen, MD: In order to answer these questions, I would like to divide refractive surgery into corneal and lens surgery.

A sophisticated preop examination before corneal refractive surgery includes a thorough fundus examination of the eye. If any retinal pathology is found, it should be treated prior to corneal refractive surgery, ie, LASIK or LASEK/PRK. I personally have not found any difference in dealing with retinal complications from those appearing typically in a myopic population. My upper range for corneal refractive surgery has been 10 D of myopia, but I have reduced this to 8 D of myopia lately.

Therefore, I have my own exclusion criteria for the highly myopic patients to corneal refractive procedures. If any postop complications occur, like peripheral retinal breaks or holes, I do not see any major difference from the preop status. In the literature, the incidence of retinal detachment following LASIK and PRK has not been higher than in the normal myopic population.

Optic neuropathy has been an issue with long suction time. However, with modern microkeratomes and sophisticated surgical techniques, this should not occur. Therefore, I do not approach the possible retinal pathology different than the way I do in any untreated refractive myopic patient.

Refractive lens surgery should be regarded from a different angle, in terms of retinal complications. If a phakic IOL is placed in the eye, a cataract could develop (which can occasionally be the case with posterior chamber phakic IOLs). We would have to deal with the cataract producing a pseudophakic eye and, with all complications known, for example, the increased risk of retinal detachment for high myopia. This situation should be avoided.

I prefer anterior and iris-supported phakic IOLs in younger patients, because I haven’t seen the cataract formation in these eyes so far. The situation is again different in clear lens extraction. With myopia, I do not perform clear lens extraction in patients younger than 50 years old, unless the eye had developed vitreous detachment. The lower range for hyperopic treatment would be 45 years old, as retinal detachment does not typically occur in these patients.

In all my patients, the possibility of retinal detachment and retinal complications are discussed, and we emphasize that after the procedure the eye still is myopic and the patient ought to have his eyes examined carefully every year.

Thomas Kohnen, MD can be reached at Johann Wolfgang Goethe University, Theodor Stern kai 7, Frankfurt am Main, 60590, Germany; +(49) 696-301-6739; fax: +(49) 696-301-3893; e-mail: kohnen@em.uni-frankfurt.de.

Lesions sometimes found

Tomoaki Nakamura, MD: In myopic patients, lesions including lattice degeneration with hole and retinal breaks are sometimes found. Since we consider those lesions as high-risk factors for retinal detachment, they should be treated with laser or cryopexy prior to refractive surgery to prevent it.

However, these treatments do not necessarily provide perfect and permanent retinal attachment in all cases. As already known, if the vitreous traction is stronger than the force of adhesion between sensory retina and retinal pigment epithelium, retinal re-detachment may develop, indicating our treatments had no effect, or there may be some cases where there existed retinal breaks other than the ones treated, and these unexpectedly develop retinal detachment.

Therefore, it is essential to carefully examine the peripheral retina and vitreoretinal surface around the treated lesions with binocular indirect ophthalmoscopy with scleral pressure or Goldmann three-mirror lens, etc. Nevertheless, it is still not possible to diagnose whether patients will suffer from retinal detachment in the future. We suggest LASEK instead of LASIK if patients have multiple retinal breaks, where we assume the vitreous traction is strong. With LASEK, we do not have to worry about the disruption of the LASIK flap during surgery.

I believe the incidence of retinal detachment after refractive surgery is low. In our clinic, only one eye of 2,194 (1,108 patients) was found to have retinal detachment after LASIK. There also are several papers reporting that such incidence is infrequent.

However, once retinal detachment is developed, we face some issues about which we need to interview patients. We must select the best surgical procedure for LASIK patients, and explain any advantages and disadvantages of the selected procedure. If patients are young and do not have posterior vitreous detachment (PVD), we recommend scleral buckling, as myopic correction can be preserved in most cases. Yet if the vitreous traction is strong and there is lattice degeneration with a hole or retinal breaks at the opposite side of original tear, we must add an encircling procedure. In such cases, myopic correction will not be preserved.

There is also a situation where we have to select vitrectomy when there are multiple retinal breaks and retinal breaks are located more posterior than vortex vein. However, in young patients, PVD is not developed in most cases and vitreous may generate proliferative changes after vitrectomy; accordingly, we must explain that PVR may develop postoperatively.

Another disadvantage of vitrectomy is cataract. For younger patients, loss of the crystalline lens means loss of accommodation, so this becomes a serious problem. When PVD is developed and retinal break is located in the upper part of the retina, we can select pneumatic retinopexy as an option. This has advantages including a simple, easy technique and no pain for patients, but there is a possibility of developing cataract at the same time.

To preserve myopic correction, it is desirable to select scleral buckling, vitrectomy and pneumatic retinopexy. When considering keeping the LASIK flap, it is desirable to select vitrectomy and pneumatic retinopexy. When taking account of postop cataract, it is not desirable to select vitrectomy or pneumatic retinopexy. In any case, the most important thing is attachment of the retina and maintaining visual function.

Tomoaki Nakamura, MD, can be reached at the Refractive Eye Clinic, 3F 25-1 Namiyose-cho Atsuta-ku, Nagoya 456-0002, Japan; +(81) 52-872-0490; fax: +(81) 52-872-0491; e-mail: rec@bc5.so-net.ne.jp.

Retinal detachment not caused by LASIK

Maurizio Zanini, MD: The worst problem I have experienced is a rhegmatogenous retinal detachment in a 54-year-old myopic patient who had undergone uneventful LASIK (preop spherical equivalent –7.5). This complication occurred more than 2 years after surgery. As in any other case reported until today, it is hard to establish a direct causal link with refractive surgery. Most eyes undergoing LASIK belong to specific subgroups in which the incidence of rhegmatogenous retinal detachment is well recognized as being much higher. Hence, I believe that retinal detachment was not caused by LASIK but rather it is characteristic of the natural history of the myopic eye.

Careful preop examination of the retinal periphery is mandatory in order to treat any retinal condition predisposing the patient to a retinal detachment. As far as postop surgical treatment is concerned, both vitrectomy and scleral buckling may be used. In either case, surgeons should be aware of the risk of flap complications, such as dehiscence, during vitreoretinal surgery.

Another condition that may be noted after refractive surgery is the development or worsening of myopic maculopathy. We had a case like this. Although it has been proposed that shock waves produced by the excimer laser might contribute to maculopathy, there is no consistent proof to demonstrate a cause-and-effect relationship in this case as well.

In conclusion, it is very important to inform patients that refractive surgery only corrects the refractive aspects of myopia, and that the myopia itself is still potentially vulnerable to serious complications.

Maurizio Zanini, MD, can be reached at Centro Salus, Via Saffi 4/h, 40131 Bologna Italy; +(39) 051-555-311; fax: +(39) 051-524-486; e-mail: salus@eyeproject.com or m.zanini@eyeproject.com.