ARRRRRGH-K: How Do We Best Care for Post-RK Patients?

A pictorial review.

BY SHERAZ M. DAYA, MD, FACP, FACS, FRCS(Ed), FRCOphth

was a promising technique for the the 3- to the 8-mm optical zone correction of low . RK relied were created, rather than the variable Unhappy RK on the effect of a series of deep radial number of 11-mm full-length incisions patients present incisions to relax the peripheral and used in the standard RK technique. flatten the central in patients I was Dr. Lindstrom’s fellow in to with myopia. The number of incisions Minneapolis at that time, and I watched varied from four to 16 and sometimes some of his earliest procedures first- practices ambitiously 32, depending on the level hand. I performed RK for a couple of periodically; know of correction required, but all incisions years in my own practice, and for the extended from the pupil to the corneal past 27 years I have regularly looked how to improve periphery in a radial pattern, like the after patients with RK-related problems. spokes of a wheel. As a result, my perspective on the pro- their quality of life. The RK technique quickly became cedure has changed over the years. more sophisticated and relatively more reproducible through the introduction PROBLEMS AFTER RK of diamond knives, pachymetry, and RK worked by essentially producing ate complications of radial nomograms that were based on the controlled ectasia in the periphery of keratotomy (RK) can occur, patient’s age and level of correction. the cornea. Because the cornea is an and, for the newest generation The Russian technique was felt to be elastic dome, the periphery became of refractive surgeons unfamiliar more effective with deeper incisions elevated, and the central area flattened with this type of incisional sur- centrally, however, there was consider- to produce the desired outcome Lgery, management can be challenging. able risk of entering the visual axis. of correcting myopia. Despite their The goal of this pictorial review is to The main determinants of effect enhance understanding of the common of RK were the size of the optical complications of RK and the rationales zone, the number of incisions, and for several management approaches. the patient’s age. The realization that there was no need to cut to the limbus BACKGROUND gave rise to the concept of minimally RK, pioneered by Professor invasive RK (mini-RK). Introduced by Svyatoslav Nikolayevich Fyodorov in Richard L. Lindstrom, MD, in 1991, 1974, first performed in Russia, and mini-RK (Figure 1) minimized the adopted by US surgeons in particular invasiveness of RK by reducing the and ophthalmologists in the rest of number, depth, and area of incisions. the world in the mid to late 1980s, In mini-RK, incisions extending from Figure 1. This eye underwent mini-RK.

AUGUST 2019 | CATARACT & REFRACTIVE SURGERY TODAY 61 - B Perhaps the most commonmost the Perhaps but patients can develop severedevelop can patients but The simplest option for mostfor option simplest The 4 Another option is the lasso stitch. There areThere stitch. lasso the is option Another Starbursts Diurnal fluctuation Progressive hyperopia Poor visual quality from increased spherical aberration Ectasia TABLE. EARLY AND LATE COMPLICATIONS OF RK vision correction. PRKafter results short-term good described have Some Lasso stitch. Progressive hyperopic shift. shift. Progressive hyperopic A Early Late refractive surgeons, but likely not the best, is to perform laserperform to is best, the not likely but surgeons, refractive usedI shift. the address to PRK) or (LASIK correction vision foundhave I long-term but 1993, in starting technique this hyperopicfurther including problems, more cause to only it 2).(Figure ectasia and progression (MMC), C mitomycin with patient post-RK The keratocytes. activated the by caused haze aAfter MMC. with PRK after haze developed 3 Figure in 3A),(Figure MMC adjunctive with treatment PRK second persistedthat haze significant more developed patient the a perform to microkeratome useda I years. 2 than more for whichkeratoplasty, lamellar anterior homoplastic superficial freea with it replaced and cornea anterior the removed visualpatient’s the of restoration in resulting flap, LASIK-type 3B).(Figure starbursts in reduction a and acuity BruceR. by developed lasso Grene the variations: useful two cantechnique Either stitch. lasso double the and MD, Grene, influctuations diurnal with patients in useful especially be progressivehyperopic arrest or slow also can It acuity. visual atechnique, lasso Grene the In term. long the in change terephthalate;(polyethylene suture nonelastic 10-0 Mersilene optic 7-mm a incisionat RK each through placed is Ethicon) thedouble is that steepening achieve to tightened and zone low-dose pilocarpine to constrict the pupil may resolve resolve may pupil the constrict to pilocarpine low-dose problem. the mostis shift hyperopic progressivea RK, after complication .of symptoms with patients by experienced often presbyopia,from accommodation of loss a to addition In com to used previously mechanism the lost have patients wellsee to unable are thus and hyperopia their for pensate near.and distance at Figure 3. Repeat PRK with MMC was performed on this post-RK eye (A). A microkeratome was performed on this post-RK eye (A). A microkeratome Figure 3. Repeat PRK with MMC lamellar keratoplasty was performed to resolve the superficial homoplastic anterior (B). significant haze that developed

2,3 The 2 aberration. 9 In one study, 31% to31% study, one In 201 In another study of RKof study another In 1 AUGUST |

The location of RK incisions in the pupillary the in incisions RK of location The In some cases, particularly inferotemporal, RKinferotemporal, particularly cases, some In Starbursts. Poor visual quality from increased spherical Ectasia. Ectasia. Shifts, fluctuations, and starbursts. and starbursts. fluctuations, Shifts, zone can cause starbursts. The phenomenon is most is phenomenon The starbursts. cause can zone there when and dilated is pupil the when night at evident to adapt patients RK Mostlight. of sources point are then debilitating, condition the find they if but, starbursts, or solution ophthalmic tartrate brimonidine prescribing RK patients often report a deterioration in visual qualityvisual in deterioration a report often patients RK developedhave patients these cases, most In age. they as which lenses, crystalline their in aberration spherical RK.by induced aberration spherical the compounds MANAGEMENT STRATEGIES predisposed to developing , and ectasia isectasia and keratoconus, developing to predisposed additionalof performance the by exacerbated sometimes ablatingBy correction. hyperopic for surgery ablative corneal thesteepens intervention secondary this areas, elevated therebytissue, weak mechanically thins also but cornea 2).(Figure progression ectatic to contributing at high altitudes that returned to baseline on descent. on baseline to returned that altitudes high at relativea and hypoxia relative be to determined were causes incisions. RK the of because metabolism corneal in reduction oftenis This time. over ectatic more become incisions originallyare or cysts epithelial have that eyes in case the and rupture of the keratotomy scars if traumatized.scarsif keratotomy the of rupture and years12 to 5 hyperopia progressive developed patients of 54% cornealperipheral continued of result a as surgery RK after flattening. central and elevation shifthyperopic moderate a experienced mountaineers eyes, positive effects, RK incisions cause several complications andcomplications several cause incisions RK effects, positive progressivea include These (Table). time over effects side starbursts,acuity, visual in fluctuations diurnal shift, hyperopic aberration,spherical increased from quality visual poor ectasia, Figure 2. Keratoconus developed in this eye after laser to correct a progressive to correct a progressive Figure 2. Keratoconus developed in this eye after laser ablation hyperopic shift. CATARACT & REFRACTIVE SURGERY TODAY

62 s IN REFRACTIVEDEBATES SURGERY DEBATES IN REFRACTIVE SURGERY s

A B A

Figure 4. Single (A) and double (B) lasso sutures. In the single-suture technique, sutures are passed through the incisions; in the double-suture technique, the sutures are passed through the stroma so they lie over the incisions. B intended amount. Patients are myopic Cataract surgery or refractive lens initially. As the suture cheese-wires exchange. Patients who have cataracts through the stroma, however, the cor- or who are of age for a refractive lens nea flattens, and the refraction heads exchange can benefit from lensectomy toward emmetropia. and implantation of a small-aperture In the double-suture technique, lens. The IC-8 IOL (AcuFocus; not two lasso sutures are fashioned at the approved by the FDA) can provide C 7- and 9-mm optical zones. Rather post-RK patients with increased depth than pass the suture through the of focus; I have found that the lens incisions, the surgeon passes the sutures is also forgiving of and through the stroma so that they lie eliminates starbursts. The patients over the incisions. Once the sutures in whom I have implanted the IC-8 cheese-wire into the midstroma, they bilaterally (Figure 6) have achieved provide a similar effect as a single lasso spectacle independence. Piggybacking suture placed through the incisions. is an alternative: An XtraFocus M93L Figure 6. AcuFocus IC-8 IOLs were implanted bilaterally The overlay technique of the double small-aperture IOL (Morcher; not in a patient who had undergone RK. The edge of the lasso is technically easier to perform approved by the FDA) is placed in the small-aperture IOL can be seen within the pupil of the than the Grene lasso and produces a sulcus over a monofocal lens in the right eye (A). In the left eye (B), retroillimination reveals similar effect without disrupting the RK capsular bag. the IC-8 IOL and the RK incisions (C). incisions (Figures 4A and 4B). Meticulous surgical planning is Phakic IOL implantation. A more important regardless of the approach to practices periodically. An understanding accurate alternative compared to lens surgery, and IOL power calculations of the procedure’s complications and lasso suturing and laser ablation is are challenging in RK patients. A options for their management can implantation of a hyperopic phakic variety of options are available, but allow surgeons to help patients achieve IOL (Figure 5) such as the Visian ICL my personal preference is to use the better visual outcomes and improve (STAAR Surgical) or the Artisan/ keratometry readings from the Holladay their quality of life. n Verisyse (Ophtec/Johnson & Johnson Report (Pentacam, Oculus Optikgeräte) Vision). An advantage of this approach and the Holladay 2 formula. 1. Deitz MR, Sanders DR, Raanan MG, DeLuca M. Long-term (5- to 12-year) follow-up of metal-blade procedures. Arch Ophthalmol. is that the IOL can be removed or Placement of the incision to 1994;112(5):614-620. replaced later if need be. access the anterior chamber is also 2. Ng JD, White LJ, Parmley VC, et al. Effects of simulated high altitude on pa- tients who have had radial keratotomy. Ophthalmology. 1996;103(3):452-457. important. RK incisions are best 3. Sanders DR, Deitz MR, Gallagher D. Factors affecting predictability of radial avoided by performing a scleral incision. keratotomy. Ophthalmology. 1985;92(9):1237-1243. Alternatively, a limbal or corneal incision 4. Ghoreishi M, Abtahi AM, Seyedzadeh I, et al. Photorefractive keratectomy in the management of postradial keratotomy hyperopia and astigmatism. J Res is best placed between the RK incisions Med Sci. 2017;22:82. and set as posteriorly as possible.

CONCLUSION SHERAZ M. DAYA, MD, FACP, FACS, FRCS(Ed), In the late 1980s, RK was considered FRCOphth to be a phenomenal procedure and the n Medical Director, Centre for Sight, East Grinstead, only option available to correct myopia. United Kingdom The drawbacks of RK became evident n Chief Medical Editor, CRST Europe Figure 5. An Artisan IOL was implanted in this eye 10 years over time, and unhappy RK patients n [email protected] after RK to address a 3.50 D progressive hyperopic shift. continue to present to ophthalmology n Financial disclosure: None

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