eMedicine Specialties > Ophthalmology > Refractive Disorders

Myopia, PRK: Follow-up

Author: Fernando H Murillo-Lopez, MD, Senior Surgeon, Unidad Privada de Oftalmologia CEMES
Contributor Information and Disclosures

Updated: Apr 18, 2006

Outcome and Prognosis

For predictability of outcome, investigators collected the following data from patients who were operated on with a VISX excimer laser in a prospective, nonrandomized, unmasked, multicenter PRK clinical study and followed them for at least 2 years:

  • In myopic PRK, refractive stability achieved at 1 year was maintained up to 12 years with no evidence of hyperopic shift, diurnal fluctuation, or late regression in the long term. Corneal haze decreased with time, with complete recovery of BSCVA. Night halos remained a significant problem in a subset of patients due to the small ablation zone size.
  • After hyperopic PRK, refractive stability achieved at 1 year was maintained up to 7.5 years with no evidence of hyperopic shift, diurnal fluctuation, or late regression. Peripheral corneal haze decreased with time but was still evident in a number of eyes at the last follow-up visit.
  • PRK for severe anisometropic amblyopia in children resulted in long-term stable reduction in refractive error and improvement in visual acuity and stereopsis, with negligible persistent corneal haze.
  • The safety and efficacy of PRK after LASIK show good reduction of refractive error and improvement of UCVA and BSCVA. A significant undercorrection of astigmatism was attributed to surgically induced astigmatism. Further studies are necessary to determine the long-term safety and stability of outcomes.

Future and Controversies

Even though several reports demonstrate that long-term visual outcome of patients treated with PRK versus LASIK is equivalent for mild-to-moderate myopia, PRK has become a second choice procedure for most refractive surgeons.

When using the excimer laser, LASIK has become the preferred technique because of the lack of a significant amount of discomfort, the faster rate of postoperative visual rehabilitation, and the greater amount of stability.

However, PRK remains useful when treating patients whose corneas are too thin to perform LASIK and leaves a 250-µm stromal bed after the ablation is performed. PRK also is the procedure of choice when treating a refractive error associated with an uneven corneal surface or a superficial leukoma.

New tools for mapping the cornea, including wavefront technology, will provide more accurate information that can be linked to the excimer laser and allow a customized ablation. Similarly, technical improvements in the design of excimer machines, such as eye-tracking devices, have minimized potential complications, such as decentration, following PRK.

 


More on Myopia, PRK

Overview: Myopia, PRK
Workup: Myopia, PRK
Treatment: Myopia, PRK
Follow-up: Myopia, PRK
References
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References

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Further Reading

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Keywords

photorefractive keratectomy, shortsighted, vision loss, visual deficit, laser surgery

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Contributor Information and Disclosures

Author

Fernando H Murillo-Lopez, MD, Senior Surgeon, Unidad Privada de Oftalmologia CEMES
Fernando H Murillo-Lopez, MD is a member of the following medical societies: American Academy of Ophthalmology
Disclosure: Nothing to disclose.

Medical Editor

Daniel S Durrie, MD, Director, Department of Ophthalmology, Division of Refractive Surgery, University of Kansas Medical Center
Daniel S Durrie, MD is a member of the following medical societies: American Academy of Ophthalmology and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Pharmacy Editor

Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles
Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Managing Editor

Louis E Probst, MD, Medical Director of Refractive Surgery, Chicago, Madison, Milwaukee, and Windsor Centers, TLC the Laser Eye Centers
Louis E Probst, MD is a member of the following medical societies: American Academy of Ophthalmology, American Society of Cataract and Refractive Surgery, and International Society of Refractive Surgery
Disclosure: Nothing to disclose.

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

 
 
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