Lacquer crack formation after LASIK

Abstract

The possible effects of LASIK on the posterior segment of the eye are not thoroughly known. Retinal detachment after LASIK, choroidal neovascularization, macular hemorrhage, and macular hole after LASIK have been described.1Ruiz-Moreno J.M. Pérez-Santonja J.J. Alió J.L. Retinal detachment in myopic eyes after laser in situ keratomileusis.Am J Ophthalmol. 1999; 128: 588-594Abstract Full Text Full Text PDF PubMed Scopus (81) Google Scholar, 2Ruiz-Moreno J.M. Pérez-Santonja J.J. Alió J.L. Choroidal neovascularization in myopic eyes after laser-assisted in situ keratomileusis.Retina. 2001; 21: 115-120Crossref PubMed Scopus (33) Google Scholar, 3Ellies P. Pietrini D. Lumbroso L. Lebuisson D.A. Macular hemorrhage after laser in situ keratomileusis for high myopia.J Cataract Refract Surg. 2000; 26: 922-924Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, 4Ruiz-Moreno J.M. Artola A. Pérez-Santonja J.J. Alió J.L. Macular hole in a myopic eye after laser in situ keratomileusis.J Refract Surg. 2002; 18: 746-749PubMed Google ScholarWe describe the characteristics and potential mechanisms of a macular lacquer crack in a myopic patient corrected by LASIK.A 37-year-old female patient with high myopia in both eyes attended our clinic to have her myopia surgically corrected. The spherical equivalent (SE) was −10.00 diopters (D) in her right eye and −8.25 D in her left eye. Preoperative best-corrected visual acuity (BCVA) was 20/32 in the right eye and 20/28 in the left. No myopic macular alterations were present in either eye before surgery. Corneal pachimetry revealed insufficient corneal thickness (520 μm for the right eye and 500 μm for the left) to be corrected with our laser (Technolas 217-C, Chiron Vision, St. Louis, MO). A phakic intraocular anterior chamber lens (Morcher GmbH, Stuttgart, Germany) implantation was performed in August 2001. The postoperative period was uneventful. By October 2001, BCVA was 20/25 (SE = −1.75) in the right eye and 20/25 (SE = −0.75) in the left. The patient asked for further correction of her myopic defect, which was performed by LASIK without complications on December 11, 2001. She described loss of vision in the same day after LASIK in her right eye. BCVA was 20/50 (SE = 0.00) in the right eye and 20/28 (SE = 0.00) in the left. Indirect ophthalmoscopy disclosed a macular hemorrhage and a lacquer crack (Fig 1A). Fluorescein angiography showed no choroidal neovascularization. No treatment was performed, and the patient was kept under observation. Three months later BCVA was 20/25 (SE = −0.50) and the macular hemorrhage had disappeared completely, leaving a residual lacquer crack (Fig 1B).Reasons for the development of lacquer cracks remain unclear. They may be the healed mechanical breaks of retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris complex and have been related to a weak Bruch's membrane. It is believed that lacquer cracks as well as other macular degenerative changes in pathologic myopia are caused by mechanical stretching of the retina and choroid within the posterior staphyloma.5Klein R.M. Green S. The development of lacquer cracks in pathologic myopia.Am J Ophthalmol. 1988; 106: 282-285Abstract Full Text PDF PubMed Google ScholarThe occurrence or extension of a lacquer crack can be associated with a macular hemorrhage that may occur in the absence of subretinal neovascularization. In highly myopic eyes subretinal hemorrhages and lacquer cracks are often found simultaneously. Klein and Curtin reported subretinal bleeding in 33% of lacquer cracks.6Klein R.M. Curtin B.J. Lacquer crack lesions in pathologic myopia.Am J Ophthalmol. 1975; 79: 386-392Abstract Full Text PDF PubMed Scopus (64) Google ScholarDifferent hypotheses have tried to explain the posterior segment pathology after LASIK, such as mechanical stress caused by the intraocular pressure (IOP) elevation produced by the pneumatic suction ring, which may induce tangential stress at the posterior segment and even cause a rupture in Bruch's membrane. Another cause of stress might be the impact of excimer laser energy on the cornea producing stress waves along the axis of the eye. Stress wave amplitudes during photoablation reach a maximal pressure focus of up to 100 atmospheres located in the posterior lens and anterior vitreous and then decrease to <10 atmospheres at the retina.7Krueger R.R. Seiler T. Gruchman T. et al.Stress wave amplitudes during laser surgery of the cornea.Ophthalmology. 2001; 108: 1070-1074Abstract Full Text Full Text PDF PubMed Scopus (59) Google ScholarIn this case subretinal bleeding signals the development of a rupture of Bruch's membrane. Increased IOP and, less probably, the wave shock during laser ablation cause significant mechanical stress on fragile highly myopic eyes.To our knowledge new lacquer cracks have not been previously described in myopic patients immediately after LASIK. Macular hemorrhages after LASIK correction of high spherical defects (−12 to −25.87 D) are often associated with poor preoperative BCVA, thinning of RPE and previous choroidal neovascularization, and Fuchs' spots. Their appearance after LASIK can be easily explained in terms of the high probability of highly myopic eyes developing lacquer cracks with time, and in many cases result in poor visual outcome. This may be due, in part, to the association of lacquer cracks with highly myopic patients in whom LASIK is nowadays not indicated as a primary surgical procedure.This is the only case of a lacquer crack appearing in a large series of myopic patients undergoing LASIK in our clinic (more than 9000 eyes). We have been able to establish a definite relationship between LASIK and the development of lacquer cracks and subretinal hemorrhages, since it appeared, and the patient described vision loss immediately after the procedure. Ohno-Matsui considers that lacquer cracks are often underdiagnosed because of their small size and the difficulty of detecting them in myopic fundi.8Ohno-Matsui K. Ito M. Tokoro T. Subretinal bleeding without choroidal neovascularization in pathologic myopia a sign of new lacquer crack formation.Retina. 1996; 16: 196-202Crossref PubMed Scopus (63) Google ScholarLacquer cracks often lead to poor visual outcomes because of choroidal neovascularization and macular atrophy in pathologic myopia. The risk of developing lacquer cracks in highly myopic patients corrected by LASIK, though uncommon, must be kept in mind. This is true especially in highly myopic patients with myopic retinopathy in whom LASIK could be used to correct residual defects after posterior chamber or phakic intraocular lens implantation. The possible effects of LASIK on the posterior segment of the eye are not thoroughly known. Retinal detachment after LASIK, choroidal neovascularization, macular hemorrhage, and macular hole after LASIK have been described.1Ruiz-Moreno J.M. Pérez-Santonja J.J. Alió J.L. Retinal detachment in myopic eyes after laser in situ keratomileusis.Am J Ophthalmol. 1999; 128: 588-594Abstract Full Text Full Text PDF PubMed Scopus (81) Google Scholar, 2Ruiz-Moreno J.M. Pérez-Santonja J.J. Alió J.L. Choroidal neovascularization in myopic eyes after laser-assisted in situ keratomileusis.Retina. 2001; 21: 115-120Crossref PubMed Scopus (33) Google Scholar, 3Ellies P. Pietrini D. Lumbroso L. Lebuisson D.A. Macular hemorrhage after laser in situ keratomileusis for high myopia.J Cataract Refract Surg. 2000; 26: 922-924Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, 4Ruiz-Moreno J.M. Artola A. Pérez-Santonja J.J. Alió J.L. Macular hole in a myopic eye after laser in situ keratomileusis.J Refract Surg. 2002; 18: 746-749PubMed Google Scholar We describe the characteristics and potential mechanisms of a macular lacquer crack in a myopic patient corrected by LASIK. A 37-year-old female patient with high myopia in both eyes attended our clinic to have her myopia surgically corrected. The spherical equivalent (SE) was −10.00 diopters (D) in her right eye and −8.25 D in her left eye. Preoperative best-corrected visual acuity (BCVA) was 20/32 in the right eye and 20/28 in the left. No myopic macular alterations were present in either eye before surgery. Corneal pachimetry revealed insufficient corneal thickness (520 μm for the right eye and 500 μm for the left) to be corrected with our laser (Technolas 217-C, Chiron Vision, St. Louis, MO). A phakic intraocular anterior chamber lens (Morcher GmbH, Stuttgart, Germany) implantation was performed in August 2001. The postoperative period was uneventful. By October 2001, BCVA was 20/25 (SE = −1.75) in the right eye and 20/25 (SE = −0.75) in the left. The patient asked for further correction of her myopic defect, which was performed by LASIK without complications on December 11, 2001. She described loss of vision in the same day after LASIK in her right eye. BCVA was 20/50 (SE = 0.00) in the right eye and 20/28 (SE = 0.00) in the left. Indirect ophthalmoscopy disclosed a macular hemorrhage and a lacquer crack (Fig 1A). Fluorescein angiography showed no choroidal neovascularization. No treatment was performed, and the patient was kept under observation. Three months later BCVA was 20/25 (SE = −0.50) and the macular hemorrhage had disappeared completely, leaving a residual lacquer crack (Fig 1B). Reasons for the development of lacquer cracks remain unclear. They may be the healed mechanical breaks of retinal pigment epithelium (RPE), Bruch's membrane, and choriocapillaris complex and have been related to a weak Bruch's membrane. It is believed that lacquer cracks as well as other macular degenerative changes in pathologic myopia are caused by mechanical stretching of the retina and choroid within the posterior staphyloma.5Klein R.M. Green S. The development of lacquer cracks in pathologic myopia.Am J Ophthalmol. 1988; 106: 282-285Abstract Full Text PDF PubMed Google Scholar The occurrence or extension of a lacquer crack can be associated with a macular hemorrhage that may occur in the absence of subretinal neovascularization. In highly myopic eyes subretinal hemorrhages and lacquer cracks are often found simultaneously. Klein and Curtin reported subretinal bleeding in 33% of lacquer cracks.6Klein R.M. Curtin B.J. Lacquer crack lesions in pathologic myopia.Am J Ophthalmol. 1975; 79: 386-392Abstract Full Text PDF PubMed Scopus (64) Google Scholar Different hypotheses have tried to explain the posterior segment pathology after LASIK, such as mechanical stress caused by the intraocular pressure (IOP) elevation produced by the pneumatic suction ring, which may induce tangential stress at the posterior segment and even cause a rupture in Bruch's membrane. Another cause of stress might be the impact of excimer laser energy on the cornea producing stress waves along the axis of the eye. Stress wave amplitudes during photoablation reach a maximal pressure focus of up to 100 atmospheres located in the posterior lens and anterior vitreous and then decrease to <10 atmospheres at the retina.7Krueger R.R. Seiler T. Gruchman T. et al.Stress wave amplitudes during laser surgery of the cornea.Ophthalmology. 2001; 108: 1070-1074Abstract Full Text Full Text PDF PubMed Scopus (59) Google Scholar In this case subretinal bleeding signals the development of a rupture of Bruch's membrane. Increased IOP and, less probably, the wave shock during laser ablation cause significant mechanical stress on fragile highly myopic eyes. To our knowledge new lacquer cracks have not been previously described in myopic patients immediately after LASIK. Macular hemorrhages after LASIK correction of high spherical defects (−12 to −25.87 D) are often associated with poor preoperative BCVA, thinning of RPE and previous choroidal neovascularization, and Fuchs' spots. Their appearance after LASIK can be easily explained in terms of the high probability of highly myopic eyes developing lacquer cracks with time, and in many cases result in poor visual outcome. This may be due, in part, to the association of lacquer cracks with highly myopic patients in whom LASIK is nowadays not indicated as a primary surgical procedure. This is the only case of a lacquer crack appearing in a large series of myopic patients undergoing LASIK in our clinic (more than 9000 eyes). We have been able to establish a definite relationship between LASIK and the development of lacquer cracks and subretinal hemorrhages, since it appeared, and the patient described vision loss immediately after the procedure. Ohno-Matsui considers that lacquer cracks are often underdiagnosed because of their small size and the difficulty of detecting them in myopic fundi.8Ohno-Matsui K. Ito M. Tokoro T. Subretinal bleeding without choroidal neovascularization in pathologic myopia a sign of new lacquer crack formation.Retina. 1996; 16: 196-202Crossref PubMed Scopus (63) Google Scholar Lacquer cracks often lead to poor visual outcomes because of choroidal neovascularization and macular atrophy in pathologic myopia. The risk of developing lacquer cracks in highly myopic patients corrected by LASIK, though uncommon, must be kept in mind. This is true especially in highly myopic patients with myopic retinopathy in whom LASIK could be used to correct residual defects after posterior chamber or phakic intraocular lens implantation.