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Choroidal neovascularization after LASIK in a patient with low myopia
LETTERS
‘‘a steepening of anterior central lens curvature’’ should not have been included in our introduction. As suggested by Galand, a forward shift of the IOL optic is the appropriate statement regarding this topic.dLuis G. Vargas, MD
Long-term results of implantation of phakic posterior chamber IOLs In their article about the long-term results of phakic posterior chamber intraocular lens (IOL) implantation, Lackner et al.1 present the complication rates of cataracts in patients with a phakic posterior chamber IOL with 3 years of follow-up. It is noted that in 76 eyes of patients with a mean age of 48.3 years, there were 11 cases (14.5%) of cataract, of which 5 (45.5%) were progressive and 3 of the 5 eventually required cataract extractions. The authors conclude that the age of the patient is an important risk factor for the development of lens opacification. They also conclude that if one were to follow the suggested criteria in which surgery is performed only in those younger than 45 years of age, the opacification rate would decrease to 5.0%. Whereas 6 cases were presented with early opacification implying intraoperative trauma, 5 cases had late presentation with no apparent predisposing factor. This represented a 6% rate of late cataract complication in which age appears to be the only factor. Considering the number of phakic IOLs implanted each year, it is likely that cataracts can present at a much earlier age in this group of patients as they get older. We think that in contrast to the authors’ conclusion, excluding patients over a certain age may only reduce the incidence of cataracts in the medium term. Long-term results must be validated. ARTHUR C.K. CHENG, MRCSED KENNETH S.C. YUEN, MRCSED DENNIS S.C. LAM, FRCS, FCROPHTH Hong Kong SAR, People’s Republic of China REFERENCE 1. Lackner B, Pieh S, Schmidinger G, et al. Long-term results of implantation of phakic posterior chamber intraocular lenses. J Cataract Refract Surg 2004; 30:2269–2276
Reply: The observation of Cheng et al. is not as far from our conclusions as they may think. We agree that the incidence of late opacifications is associated with a more vulnerable lens in advanced age. However, with the case numbers in this study, it would be inappropriate to apply inferential statistics to this association. At present, the assumption that the lens is constantly traumatized and therefore opacifies more readily after intraocular contact lens (ICL) implantation irrespective of patient age at the time of implantation is as valid as the assumption that it is patient age at the time of surgery that is the risk factor and the effect of surgery decreases with time. In light of recent publications that report significantly lower midterm rates of opacification in patients younger than 45 years (at the time of implantation), the second option may still prove to be more valid. We are as convinced as Cheng et al. that only long-term investigations can tell us more about the reaction of the crystalline lens to ICL implantation, preferably from the centers that have reported
4
a higher incidence of opacification in short-term results.dBirgit Lackner, MD
Choroidal neovascularization after LASIK in a patient with low myopia Saeed et al.1 report a single case of choroidal neovascularization (CNV) 3 months after laser in situ keratomileusis (LASIK) for low myopia. After a discussion featuring indefinite terms such as could, probably, and possibility, they conclude: ‘‘.the potential risks of LASIK outweigh its benefits.’’1 I believe there are 2 errors in the author’s analysis. First, they group the affected eye, which had 2.75 diopters (D) of myopia, with eyes that had more than 13.00 D of myopia. Second, they define a risk for all eyes with low myopia having LASIK on the basis of a single case. Eyes with greater than 6.0 D of myopia in which the basic abnormality is excessive axial elongation are known to be at increased risk for CNV.2,3 The authors admit an incidence of CNV in high myopia of 5% to 10% but do not present evidence for a higher incidence in highly myopic eyes that have had LASIK. Also, CNV is common in some general populations with an incidence of between 0.4% and 1.1% in patients older than 43 years4 and up to 3.5% in the elderly.5 Without proper assessment of the incidence of CNV after LASIK for low myopia and comparison with a matched control group, this report remains an isolated novelty. Therefore, I suggest that the authors’ conclusions are currently unfounded and unjustified and should be moderated. C. STEVEN BAILEY, FRCS, FRCOPHTH London, United Kingdom REFERENCES 1. Saeed M, Poon W, Goyal S, et al. Choroidal neovascularization after laser in situ keratomileusis in a patient with low myopia. J Cataract Refract Surg 2004; 30:2632–2635 2. Avila MP, Weiter JJ, Jalkh AE, et al. Natural history of choroidal neovascularization in degenerative myopia. Ophthalmology 1984; 91:1573– 1580. discussion by BKJCurtin, 1580–1581 3. Hotchkiss ML, Fine SL. Pathologic myopia and choroidal neovascularization. Am J Ophthalmol 1981; 91:177–183 4. Tomany SC, Wang JJ, van Leeuwen R, et al. Risk factors for incident agerelated macular degeneration; pooled findings from 3 continents. Ophthalmology 2004; 111:1280–1287 5. Gregor Z, Joffe L. Senile macular changes in the black African. Br J Ophthalmol 1978; 62:547–550
Proper evaluation of accommodating IOLs In their article on the changes in accommodation postimplantation of the Crystalens AT-45 intraocular lens (IOL), Marchini et al.1 show paired photographs from the unaccommodated and accommodated states of the same eye. The authors show (Figure 1) that both the corneal surface and the anterior surface of the
J CATARACT REFRACT SURG - VOL 32, JANUARY 2006
‘‘a steepening of anterior central lens curvature’’ should not have been included in our introduction. As suggested by Galand, a forward shift of the IOL optic is the appropriate statement regarding this topic.dLuis G. Vargas, MD
Long-term results of implantation of phakic posterior chamber IOLs In their article about the long-term results of phakic posterior chamber intraocular lens (IOL) implantation, Lackner et al.1 present the complication rates of cataracts in patients with a phakic posterior chamber IOL with 3 years of follow-up. It is noted that in 76 eyes of patients with a mean age of 48.3 years, there were 11 cases (14.5%) of cataract, of which 5 (45.5%) were progressive and 3 of the 5 eventually required cataract extractions. The authors conclude that the age of the patient is an important risk factor for the development of lens opacification. They also conclude that if one were to follow the suggested criteria in which surgery is performed only in those younger than 45 years of age, the opacification rate would decrease to 5.0%. Whereas 6 cases were presented with early opacification implying intraoperative trauma, 5 cases had late presentation with no apparent predisposing factor. This represented a 6% rate of late cataract complication in which age appears to be the only factor. Considering the number of phakic IOLs implanted each year, it is likely that cataracts can present at a much earlier age in this group of patients as they get older. We think that in contrast to the authors’ conclusion, excluding patients over a certain age may only reduce the incidence of cataracts in the medium term. Long-term results must be validated. ARTHUR C.K. CHENG, MRCSED KENNETH S.C. YUEN, MRCSED DENNIS S.C. LAM, FRCS, FCROPHTH Hong Kong SAR, People’s Republic of China REFERENCE 1. Lackner B, Pieh S, Schmidinger G, et al. Long-term results of implantation of phakic posterior chamber intraocular lenses. J Cataract Refract Surg 2004; 30:2269–2276
Reply: The observation of Cheng et al. is not as far from our conclusions as they may think. We agree that the incidence of late opacifications is associated with a more vulnerable lens in advanced age. However, with the case numbers in this study, it would be inappropriate to apply inferential statistics to this association. At present, the assumption that the lens is constantly traumatized and therefore opacifies more readily after intraocular contact lens (ICL) implantation irrespective of patient age at the time of implantation is as valid as the assumption that it is patient age at the time of surgery that is the risk factor and the effect of surgery decreases with time. In light of recent publications that report significantly lower midterm rates of opacification in patients younger than 45 years (at the time of implantation), the second option may still prove to be more valid. We are as convinced as Cheng et al. that only long-term investigations can tell us more about the reaction of the crystalline lens to ICL implantation, preferably from the centers that have reported
4
a higher incidence of opacification in short-term results.dBirgit Lackner, MD
Choroidal neovascularization after LASIK in a patient with low myopia Saeed et al.1 report a single case of choroidal neovascularization (CNV) 3 months after laser in situ keratomileusis (LASIK) for low myopia. After a discussion featuring indefinite terms such as could, probably, and possibility, they conclude: ‘‘.the potential risks of LASIK outweigh its benefits.’’1 I believe there are 2 errors in the author’s analysis. First, they group the affected eye, which had 2.75 diopters (D) of myopia, with eyes that had more than 13.00 D of myopia. Second, they define a risk for all eyes with low myopia having LASIK on the basis of a single case. Eyes with greater than 6.0 D of myopia in which the basic abnormality is excessive axial elongation are known to be at increased risk for CNV.2,3 The authors admit an incidence of CNV in high myopia of 5% to 10% but do not present evidence for a higher incidence in highly myopic eyes that have had LASIK. Also, CNV is common in some general populations with an incidence of between 0.4% and 1.1% in patients older than 43 years4 and up to 3.5% in the elderly.5 Without proper assessment of the incidence of CNV after LASIK for low myopia and comparison with a matched control group, this report remains an isolated novelty. Therefore, I suggest that the authors’ conclusions are currently unfounded and unjustified and should be moderated. C. STEVEN BAILEY, FRCS, FRCOPHTH London, United Kingdom REFERENCES 1. Saeed M, Poon W, Goyal S, et al. Choroidal neovascularization after laser in situ keratomileusis in a patient with low myopia. J Cataract Refract Surg 2004; 30:2632–2635 2. Avila MP, Weiter JJ, Jalkh AE, et al. Natural history of choroidal neovascularization in degenerative myopia. Ophthalmology 1984; 91:1573– 1580. discussion by BKJCurtin, 1580–1581 3. Hotchkiss ML, Fine SL. Pathologic myopia and choroidal neovascularization. Am J Ophthalmol 1981; 91:177–183 4. Tomany SC, Wang JJ, van Leeuwen R, et al. Risk factors for incident agerelated macular degeneration; pooled findings from 3 continents. Ophthalmology 2004; 111:1280–1287 5. Gregor Z, Joffe L. Senile macular changes in the black African. Br J Ophthalmol 1978; 62:547–550
Proper evaluation of accommodating IOLs In their article on the changes in accommodation postimplantation of the Crystalens AT-45 intraocular lens (IOL), Marchini et al.1 show paired photographs from the unaccommodated and accommodated states of the same eye. The authors show (Figure 1) that both the corneal surface and the anterior surface of the
J CATARACT REFRACT SURG - VOL 32, JANUARY 2006