A long-term study of photorefractive keratectomy

Rajan, Madhavan S.; Jaycock, Philip D.; O’Brart, David; Nystrom, H. Hamberg; Marshall, John

doi:10.1016/j.ophtha.2004.05.019

Cited by 62 publications

(35 citation statements)

References 62 publications

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“…PRK continues to represent an alternative to laser in situ keratomileusis (LASIK) for many patients, including those with thinner corneas or corneal topographic abnormalities (Netto et al, 2006b; Rajan et al, 2004). The corneal wound healing process following PRK involves a very complex, and sometime unpredictable, biological response.…”

Section: Loss Of Corneal Transparency Related To Corneal Surgery mentioning

confidence: 99%

Cellular and extracellular matrix modulation of corneal stromal opacity

Torricelli

Wilson

2014

Experimental Eye Research

100

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Stromal transparency is a critical factor contributing to normal function of the visual system. Corneal injury, surgery, disease and infection elicit complex wound healing responses that serve to protect against insults and maintain the integrity of the cornea, and subsequently to restore corneal structure and transparency. However, in some cases these processes result in prolonged loss of corneal transparency and resulting diminished vision. Corneal opacity is mediated by the complex actions of many cytokines, growth factors, and chemokines produced by the epithelial cells, stromal cells, bone marrow-derived cells, lacrimal tissues, and nerves. Myofibroblasts, and the disorganized extracellular matrix produced by these cells, are critical determinants of the level and persistence of stromal opacity after corneal injury. Decreases in corneal crystallins in myofibroblasts and corneal fibroblasts contribute to cellular opacity in the stroma. Regeneration of a fully functional epithelial basement membrane (BM) appears to have a critical role in the maintenance of corneal stromal transparency after mild injuries and recovery of transparency when opacity is generated after severe injuries. The epithelial BM likely has a regulatory function whereby it modulates epithelium-derived growth factors such as transforming growth factor (TGF) β and platelet-derived growth factor (PDGF) that drive the development and persistence of myofibroblasts from precursor cells. The purpose of this article is to review the factors involved in the maintenance of corneal transparency and to highlight the mechanisms involved in the appearance, persistency and regression of corneal opacity after stromal injury.

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Section: Loss Of Corneal Transparency Related To Corneal Surgery mentioning

confidence: 99%

Cellular and extracellular matrix modulation of corneal stromal opacity

Torricelli

Wilson

2014

Experimental Eye Research

100

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“…Outcomes of PRK and LASIK are reported to be comparable, 1 and both procedures are reasonably safe, effective, and predictable for correcting low to moderate myopia. 2,3 Nevertheless, the most frequently reported complications include glare, halos, difficulty with night vision, decreased contrast sensitivity, transient increases in intraocular pressure, myopic regression, and mild subepithelial haze. [2][3][4][5] The plasminogen activator cascade has been implicated in many physiological and pathologic events such as wound repair, inflammation, angiogenesis, ovulation, neuronal plasticity, and neoplasia.…”

mentioning

confidence: 99%

“…2,3 Nevertheless, the most frequently reported complications include glare, halos, difficulty with night vision, decreased contrast sensitivity, transient increases in intraocular pressure, myopic regression, and mild subepithelial haze. [2][3][4][5] The plasminogen activator cascade has been implicated in many physiological and pathologic events such as wound repair, inflammation, angiogenesis, ovulation, neuronal plasticity, and neoplasia. 6 Urokinase-type plasminogen activator (uPA) and tissuetype plasminogen activator (tPA), 2 extracellular serine proteases, convert plasminogen to plasmin and thereby catalyze extracellular proteolysis.…”

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confidence: 99%

Plasminogen activator inhibitor in human tears after laser refractive surgery

Csutak

Silver

Tőzsér

et al. 2008

Journal of Cataract and Refractive Surgery

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The similarity in the general time pattern of PAI-2 after PRK and LASIK suggests commonality in the enzymatic control response to corneal surgical wounding. Taken in the context of previous work, the observed levels of PAI-2 concentration in eyes with and without opacification suggest that in the postsurgical period, PAI-2 is not the controlling mechanism for the later development of corneal opacification and haze.

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“…Our results also matched with study by Salz J I, Maguen E, Nesburn AB et al 6 and study by Rajan Madhavan. 7 With high corrections, the stromal wound healing after PRK can lead to haze formation in high percentage of cases. Haze is probably the major complication of PRK because not only does the loss of transparency results in visual loss, also stromal reaction induce refractive regression and increase corneal surface irregularity.…”

Section: Discussionmentioning

confidence: 99%

PRK – Photo Refractive Keratectomy in Correction of Myopia: How Useful Is It?

Pande¹,

Mahatme²,

Borkar³

et al. 2015

jemds

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ABSTRACT:The study comprised of retrospective and prospective evaluation of 30 eyes treated with PRK -Photo Refractive Keratectomy at Mahatme Eye Bank Eye Hospital, Nagpur India. Our results show that PRK is less safe, less effective and less predictable procedure in correcting high and extreme myopia and myopic astigmatism. KEYWORDS: Myopia, refractive surgery, Photo Refractive Keratectomy -PRK, keratome, hansatome, spherical equivalent (SE) refraction, BSCVA (Best surgically corrected visual acuity), UCVA (Uncorrected visual acuity), corneal haze, astigmatism. INTRODUCTION:PRK stands for Photo Refractive Keratectomy. PRK was the first type of laser eye surgery for vision correction and is the predecessor to the popular LASIK procedure. First PRK procedure was performed in 1987 by Dr. Theo Seiler, 1 then at the Free University Medical Center in Berlin, Germany. The main difference between PRK and LASIK is that in LASIK surgery a thin, hinged flap is created on the cornea to access the treatment area, whereas in PRK the cornea's entire epithelial (outer) layer is removed to expose the area and no flap is created. PRK is still commonly performed and offers advantages over LASIK for some patients.PRK advantages includes less depth of laser treatment than LASIK, suitable for patients with a thin cornea, no risk of corneal flap complications and reduced risk of compromised corneal thickness. The disadvantages of PRK are slower recovery than LASIK, best vision takes longer to obtain, increased risk of post-surgery infection, inflammation and haze and more eye discomfort during early PRK recovery, compared with recovery after LASIK surgery. 2 Unlike LASIK, in PRK corneal flap is not created. Instead, the outer layer of the cornea is removed to expose an area for a laser to reshape. This makes PRK a better choice for people whose eyes meet certain criteria, such as having thin corneas or chronically dry eyes. The most significant differences between PRK and LASIK are the initial discomfort and the speed of visual recovery. Recovery from PRK takes a little longer than from LASIK because the outer layer of the cornea needs time to heal.The present study aimed at finding out efficacy, safety, predictability and visual outcome of PRK in high myopia.

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A long-term study of photorefractive keratectomy

Cited by 62 publications

References 62 publications

Cellular and extracellular matrix modulation of corneal stromal opacity

Cellular and extracellular matrix modulation of corneal stromal opacity

Plasminogen activator inhibitor in human tears after laser refractive surgery

PRK – Photo Refractive Keratectomy in Correction of Myopia: How Useful Is It?

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