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OCT and Cataract
Letters to the Editor power. Ultraviolet radiation is applied at clearly defined postoperative times. Between these time points and during the first 2 postoperative weeks, it is mandatory for the patient to protect the eye from any unscheduled UV exposure by using UV protection glasses.4,5 The proof of principle of the method was given recently in 2 pilot studies for the correction of myopia and hyperopia.4,5 We here report on the implantation of a ⫹10.0 diopter (D) LAL in the left eye of a 57-year-old female patient with bilateral cataract that we performed in April 2009. Preoperatively, manifest refraction was ⫺9.75 ⫺1.25 ⫻ 175 and best spectacle-corrected visual acuity (BSCVA) was 20/25. Bilateral slit lamp examination and examination of the central and peripheral retina showed no pathological findings except for the cataract. Surgery was uneventful and the postoperative examinations at 1 day and 1 week after surgery showed regular findings. At day 14 after surgery, the point in time when the first UV irradiation is performed following the manufacturer’s protocol, the patient reported decreased vision and halos in the operated eye. Refraction was ⫺1.25 ⫺0.5 ⫻ 115 and BSCVA was 20/40. We performed the UV irradiation as planned. One week later, refraction was sphere (sph) ⫺3.25 and BSCVA had decreased to 20/125. We noted a distinct paracentral elevation in the lens in slit lamp examination (Fig 1 A-B, available at http://aaojournal.org). Upon questioning, the patient admitted that she had not used the UV protecting glasses at several occasions during the postoperative period and had exposed herself to sunlight for several hours. We explanted the LAL and implanted a conventional intraocular lens (⫹10.0 D Acrysof Natural, Alcon Laboratories Inc, Fort Worth, TX) (Fig 1 C-D, available at http://aaojournal.org). At 1 week after the lens exchange, refraction was sph ⫺0.5 and BSCVA was 20/25. This report demonstrates that postoperative compliance might be of extraordinary importance in patients receiving LALs and that the sensitivity by which the lens reacts to unplanned UV exposure might be extraordinarily high.
OCT and Cataract Dear Editor: We read with great interest the study by Takamura et al,1 describing the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery. As the primary outcome measure, they used optical coherence tomography (OCT) for the measurement of retinal thickness before and after cataract surgery. However, they did not report specific exclusion criteria based on OCT measurements. Specifically, the minimum preoperative signal strength required for the present study should have been reported. Previous studies have reported that the lens opacities affect the image quality of OCT scans as indicated by low signalto-noise ratio.2,3 Our experience, as well as other reports, have shown that OCT instrument may not obtain reliable scans when major lens opacities specially cortical and subcapsular types are present.2,3 In a study for evaluation of the influence of cataract on retinal nerve fiber layer (RNFL) thickness measurements by stratus OCT, Savini et al,2 excluded 18.9% of patients because adequate RNFL imaging quality was precluded by posterior subcapsular cataract (grade 3 or higher). Similarly, van Velthoven et al3 reported that 19% of OCT scans in patients with posterior subcapsular cataract had poor quality. Moreover, an increase in signal strength, seen after cataract surgery, was reported to result in an increase in retinal thickness.2– 4 Although this error may be small, the influence of scan quality on retinal thickness measurement may cause a systematic error when series of scans with different qualities are compared.2,3 This should be considered in all studies designed to compare pre-and post-cataract surgery retinal thickness measurements. KHALIL GHASEMI FALAVARJANI, MD MEHDI MODARRES, MD AMINOLLAH NIKEGHBALI, MD Tehran, Iran References
FARHAD HAFEZI, MD, PHD THEO SEILER, MD, PHD HANS PETER ISELI, MD Zurich, Switzerland References 1. Sandstedt CA, Chang SH, Grubbs RH, Schwartz DM. Lightadjustable lens: customizing correction for multifocality and higher-order aberrations. Trans Am Ophthalmol Soc 2006; 104:29 –39. 2. Schwartz DM. Light-adjustable lens. Trans Am Ophthalmol Soc 2003;101:417–36. 3. Schwartz DM, Sandstedt CA, Chang SH, et al. Light-adjustable lens: development of in vitro nomograms. Trans Am Ophthalmol Soc 2004;102:67–72; discussion 72– 4. 4. Chayet A, Sandstedt C, Chang S, et al. Correction of myopia after cataract surgery with a light-adjustable lens. Ophthalmology 2009;116:1432–5. 5. Chayet A, Sandstedt CA, Chang SH, et al. Correction of residual hyperopia after cataract surgery using the light adjustable intraocular lens technology. Am J Ophthalmol 2009; 147:392–7. e1.
1. Takamura Y, Kubo E, Akagi Y. Analysis of the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery. Ophthalmology 2009;116:1151–7. 2. Savini G, Zanini M, Barboni P. Influence of pupil size and cataract on retinal nerve fiber layer thickness measurements by stratus OCT. J Glaucoma 2006;15:336 – 40. 3. van Velthoven MEJ, van der Linden MH, de Smet MD, et al. Influence of cataract on optical coherence tomography image quality and retinal thickness. Br J Ophthalmol 2006;90:1259 – 62. 4. von Jagow B, Ohrloff C, Kohnen T. Macular thickness after uneventful cataract surgery determined by optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2007;245: 1765–71.
Author reply Dear Editor: We thank the correspondents for their interest in our article. In this study, we enrolled patients with diabetes who had significant lens opacity (more than grade 3 for any type of cataract: cortical, nuclear, or posterior subcapsular) by the lens opacities classification system (LOCS) III classifica-
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OCT and Cataract Dear Editor: We read with great interest the study by Takamura et al,1 describing the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery. As the primary outcome measure, they used optical coherence tomography (OCT) for the measurement of retinal thickness before and after cataract surgery. However, they did not report specific exclusion criteria based on OCT measurements. Specifically, the minimum preoperative signal strength required for the present study should have been reported. Previous studies have reported that the lens opacities affect the image quality of OCT scans as indicated by low signalto-noise ratio.2,3 Our experience, as well as other reports, have shown that OCT instrument may not obtain reliable scans when major lens opacities specially cortical and subcapsular types are present.2,3 In a study for evaluation of the influence of cataract on retinal nerve fiber layer (RNFL) thickness measurements by stratus OCT, Savini et al,2 excluded 18.9% of patients because adequate RNFL imaging quality was precluded by posterior subcapsular cataract (grade 3 or higher). Similarly, van Velthoven et al3 reported that 19% of OCT scans in patients with posterior subcapsular cataract had poor quality. Moreover, an increase in signal strength, seen after cataract surgery, was reported to result in an increase in retinal thickness.2– 4 Although this error may be small, the influence of scan quality on retinal thickness measurement may cause a systematic error when series of scans with different qualities are compared.2,3 This should be considered in all studies designed to compare pre-and post-cataract surgery retinal thickness measurements. KHALIL GHASEMI FALAVARJANI, MD MEHDI MODARRES, MD AMINOLLAH NIKEGHBALI, MD Tehran, Iran References
FARHAD HAFEZI, MD, PHD THEO SEILER, MD, PHD HANS PETER ISELI, MD Zurich, Switzerland References 1. Sandstedt CA, Chang SH, Grubbs RH, Schwartz DM. Lightadjustable lens: customizing correction for multifocality and higher-order aberrations. Trans Am Ophthalmol Soc 2006; 104:29 –39. 2. Schwartz DM. Light-adjustable lens. Trans Am Ophthalmol Soc 2003;101:417–36. 3. Schwartz DM, Sandstedt CA, Chang SH, et al. Light-adjustable lens: development of in vitro nomograms. Trans Am Ophthalmol Soc 2004;102:67–72; discussion 72– 4. 4. Chayet A, Sandstedt C, Chang S, et al. Correction of myopia after cataract surgery with a light-adjustable lens. Ophthalmology 2009;116:1432–5. 5. Chayet A, Sandstedt CA, Chang SH, et al. Correction of residual hyperopia after cataract surgery using the light adjustable intraocular lens technology. Am J Ophthalmol 2009; 147:392–7. e1.
1. Takamura Y, Kubo E, Akagi Y. Analysis of the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery. Ophthalmology 2009;116:1151–7. 2. Savini G, Zanini M, Barboni P. Influence of pupil size and cataract on retinal nerve fiber layer thickness measurements by stratus OCT. J Glaucoma 2006;15:336 – 40. 3. van Velthoven MEJ, van der Linden MH, de Smet MD, et al. Influence of cataract on optical coherence tomography image quality and retinal thickness. Br J Ophthalmol 2006;90:1259 – 62. 4. von Jagow B, Ohrloff C, Kohnen T. Macular thickness after uneventful cataract surgery determined by optical coherence tomography. Graefes Arch Clin Exp Ophthalmol 2007;245: 1765–71.
Author reply Dear Editor: We thank the correspondents for their interest in our article. In this study, we enrolled patients with diabetes who had significant lens opacity (more than grade 3 for any type of cataract: cortical, nuclear, or posterior subcapsular) by the lens opacities classification system (LOCS) III classifica-
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