Why I recommend PRK

October 24, 2013

Patient satisfaction with PRK is similar to that of LASIK, with greater than 95% reporting satisfied or extremely satisfied. When PRK is the best procedure for your patient, help him understand the benefits of surface ablation while alleviating his disappointment about not qualifying for LASIK.

One of the most common questions I hear from patients: Why am I not a good candidate for LASIK, and why are you recommending PRK? I answer by assuring the patient that I am recommending PRK because it is the procedure that gives you the best chance of 20/20 vision safely. Let’s discuss the clinical findings that can lead to a recommendation of PRK.

Why PRK?Thin corneas. One of the most important factors when considering elective corneal surgery is safety. Patients who have thinner corneas (less than 500 mµ) may be at greater risk for corneal destabilization or the development of ectasia.1 While every cornea is biomechanically unique, we know that the more collagen fibers we alter, the greater the risk for biomechanical instability. Because surface ablation does not require a stromal corneal flap created during LASIK, we alter fewer of the collagen fibers most important for corneal stability.

Topographic irregularity. While keratoconus is reported to have an incidence of 1 in 2,000 in the general population, higher incidence is reported in certain populations, such as 1 in 436 in Asian populations.2 As many as 32% of corneal topography studies have some asymmetry or irregularity.3 (Figure 1). Many surgeons prefer to minimize tissue removal for patients with topographic irregularities.4

 

Figure 1. Irregular topography. (Photo courtesy William Tullo, OD)

Dry eye. The majority of patients who undergo surface ablation has some subjective dry eye symptoms during the post-operative period, but studies show a return to baseline for most patients after 12 months.5 Some studies also suggest fewer dryness symptoms after PRK as compared to patients who have LASIK surgery.6

Epithelial disease. Patients who suffer from certain types of epithelial disease such as recurrent corneal erosion or epithelial basement membrane dystrophy may increase their risks of increased symptomatology if a LASIK flap is created. Surface ablation may indeed offer a therapeutic treatment for patients with epithelial disease.7

Research supports that visual outcomes of surface ablation are similar to LASIK in low to moderate myopia with or without astigmatism with experienced surgeons.8 PRK also offers the following advantages as compared to LASIK:

  • No risk of flap complications

  • Surgery itself is faster, more comfortable, and less complex

  • More room for enhancements or additional surgery

  • Occupation/hobby with high risk of ocular trauma

It is important to remind patients who have surface ablation that visual recovery is slower than LASIK, and many patients can experience discomfort during the early post-operative period. I explain to patients that PRK is more comfortable than LASIK during the actual procedure, but less comfortable for a few days afterwards. I assure them that they will be provided medication to minimize any discomfort and a bandage contact lens will be placed on their eye for about 4 days to maximize comfort and vision. Most patients can expect legal driving vision within the first week, which will gradually improve to their best acuity in several weeks.

Patient satisfaction with PRK is similar to that of LASIK, with greater than 95% reporting satisfied or extremely satisfied.9 When PRK is the best procedure for your patient, help him understand the benefits of surface ablation while alleviating his disappointment about not qualifying for LASIK. Setting proper patient expectations and educating patients with clinical information will allow your patient to make the choice best for his vision.ODT

References
1. Randleman JB, Trattler WB, Stulting RD. Validation of the Ectasia Risk Score System for preoperative laser in situ keratomileusis screening. Am J Ophthalmol. 2008 May;145(5):813-8.

2. Pearson AR, Soneji B, Sarvananthan N, Sandford-Smith JH. Does ethnic origin influence the incidence or severity of keratoconus? Eye (Lond). 2000 Aug;14 (Pt 4):625-8.

3. Tabbara KF, Koth AA.  Risk factors for corneal ectasia after LASIK. Ophthalmology. 2006 Sep;113(9):1618-22.

4.  Hardten DR, Gosavi VV. Photorefractive keratectomy in eyes with atypical topography. J Cataract Refract Surg. 2009 Aug;35(8):1437-44.

5. Murakami Y, Manche EE. Prospective, randomized comparison of self-reported postoperative dry eye and visual fluctuation in LASIK and photorefractive keratectomy. Ophthalmology. 2012 Nov;119(11):2220-4.

6. Albietz JM, McLennan SG, Lenton LM. Ocular surface management of photorefractive keratectomy and laser in situ keratomileusis. J Refract Surg. 2003 Nov-Dec;19(6):636-44.

7. Jain S, Austin DJ. Phototherapeutic keratectomy for treatment of recurrent corneal erosion. J Cataract Refract Surg. 1999 Dec;25(12):1610-4

8. el Danasoury MA, el Maghraby A, Klyce SD, Mehrez K. Comparison of photorefractive keratectomy with excimer laser in situ keratomileusis in correcting low myopia (from -2.00 to -5.50 diopters). A randomized study. Ophthalmol. 1999;106(2):411-420; discussion 420-421.

9. Manche EE, Haw WW Wavefront-guided laser in situ keratomileusis (Lasik) versus wavefront-guided photorefractive keratectomy (Prk): a prospective randomized eye-to-eye comparison (an American Ophthalmological Society thesis). Trans Am Ophthalmol Soc. 2011 Dec;109:201-20.