ORIGINAL ARTICLE
Analysis of choroidal thickness in eyes treated with focal laser photocoagulation using SD-OCT Mehreen Adhi, MBBS, Ahmad A. Alwassia, MD, Jay S. Duker, MD ABSTRACT ● RÉSUMÉ Objective: To analyze the effect of focal laser photocoagulation on choroidal thickness in patients with diabetic macular edema (DME), using spectral-domain optical coherence tomography (SD-OCT). Design: Retrospective review. Participants: Twenty-two eyes of 22 patients diagnosed with DME and treated with focal laser photocoagulation (treatment group) and 19 fellow treatment-naive eyes (control group) who underwent high-definition 1-line raster scanning using the Cirrus SD-OCT at the New England Eye Center, Tufts Medical Center (Boston, Mass.) between November 2009 and April 2012. Methods: The SD-OCT images were analyzed for the measurement of choroidal thickness by 2 independent observers experienced in analyzing OCT images, before treatment and at 3 months after focal laser photocoagulation in the treatment group, and at baseline (when the fellow eye in the treatment group was treated) and at 3-month follow-up in the control group. Results: There was no significant difference in the mean choroidal thickness in the treatment and control groups (n ¼ 22, p ¼ 0.93 and n ¼ 19, p ¼ 0.1, respectively) at 3-month follow-up. There was no significant association of the number of focal laser treatments with the mean choroidal thickness (n ¼ 41, r ¼ 0.31, p ¼ 0.68). Conclusions: Focal laser photocoagulation does not appear to alter choroidal thickness in eyes with DME in the short term, as assessed using SD-OCT. Long-term follow-up of eyes with DME and other retinal diseases treated with laser photocoagulation may provide further insight into the effects of this treatment modality on the choroid. Objet : Analyse de l’effet de la photocoagulation focale au laser sur l’épaisseur de la choroïde chez les patients qui ont un œdème maculaire diabétique (ŒMD), à l’aide de la tomographie par cohérence optique du domaine spectral (TCO-DS). Nature : Rétrospective. Participants : Vingt-deux yeux de 22 patients ayant un diagnostic d’ŒMD et soignés par photocoagulation focale au laser (« groupe traité») et 19 yeux contralatéraux naïfs au traitement (« groupe témoin ») qui ont subi une balayage tramé d’une ligne de haute définition en utilisant la TCO-DS de Cirrus au Centre oculaire de la Nouvelle-Angleterre, du Tufts Medical Center, à Boston, entre les mois de novembre 2009 et avril 2012. Méthode : Les images de la TCO-DS ont servi à la mesure de l’épaisseur choroïdienne par deux observateurs indépendants et expérimentés dans l’analyse des images de TCO, avant le traitement et 3 mois après la photocoagulation focale au laser dans un « groupe traité », à la ligne de départ (lors du traitement de l’autre œil) et après un suivi de 3 mois dans le « groupe témoin ». Résultats : Il n’y avait pas de différence significative dans la moyenne d’épaisseur de la choroïde dans les groupes de traitement et celui des témoins (n = 22, p = 0,93 et n = 19, p = 0,1 respectivement) après trois mois de suivi. I l n’y avait pas d’association significative entre le nombre de traitements focaux au laser et l’épaisseur moyenne de la choroïde (n = 41, r = 0,31, p = 0,68). Conclusion : La photocoagulation focale au laser ne semble pas modifier l’épaisseur de la choroïde des yeux ayant un ŒMD à court terme, tel qu’évalué par TCO-DS. Le suivi à long terme des yeux atteints de l’ŒMD et d’autres maladies de la rétine, et soignés par photocoagulation au laser peut aider à voir davantage les effets de cette modalité de traitement de la choroïde.
Choroidal vascular damage plays an important role in the pathogenesis of advanced diabetic retinopathy.1–3 Current treatments for chorioretinal diseases, such as anti–vascular endothelial growth factor (anti-VEGF) agents and photodynamic therapy (PDT), have been shown to cause an alteration in choroidal thickness.4–7 Although there is conflicting evidence on the effects of anti-VEGF agents on choroidal thickness,4–6 PDT has been shown to cause a significant reduction in the choroidal thickness.7 Focal laser photocoagulation is a much more focal treatment, when compared with anti-VEGF agents and PDT, and is used as a standard for the treatment of diabetic macular edema (DME).8,9 Changes in retinal function have been demonstrated after focal laser photocoagulation in DME.10 To our knowledge, the effects of focal laser photocoagulation
on the choroid have not been evaluated to date. This study aimed to assess the effects of focal laser photocoagulation on choroidal thickness in eyes with DME, using spectral-domain optical coherence tomography (SD-OCT).
From the New England Eye Center, Tufts Medical Center, Boston, Mass.
Can J Ophthalmol 2013;48:535–538 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.05.010
Originally received Mar. 28, 2013. Accepted May 17, 2013
METHODS A retrospective review identified 22 eyes of 22 patients diagnosed with DME and treated with focal laser photocoagulation (treatment group), and 19 fellow treatmentnaive eyes (control group) who underwent high-definition 1-line raster scanning using the Cirrus SD-OCT at the New England Eye Center, Tufts Medical Center (Boston, Mass.) between November 2009 and April 2012.
Correspondence to Jay S. Duker, MD, New England Eye Center, Tufts Medical Center, 800 Washington Street, Boston, MA 02111; [email protected] CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
535
Effect of focal laser therapy on the choroid—Adhi et al.
Fig. 1 — Effect of focal laser photocoagulation on choroidal thickness (CT). A, Graph representing mean CT at all locations before and 3 months after focal laser photocoagulation (n ¼ 22, treatment group). B, Graph representing mean CT at all locations at baseline and at 3-month follow-up (n ¼ 19, control group). The p values represent the results of paired Student t test; n represents the number of eyes. 0.5, mm from the fovea.
SD-OCT scanning was performed using Cirrus highdefinition 1-line raster (Carl Zeiss Meditec Inc, Dublin, Calif.), which is a 6-mm line scan consisting of 4096 A-scans, an imaging speed of 27 000 A-scans per second, and a 5-μm resolution. The enhanced depth imaging function which theoretically improves visualization of the choroid, was not available at the time these scans were obtained. All scans had an intensity of 6/10 or greater and were taken as close to the fovea as possible to image the thinnest point of the macula. Patients with concomitant ocular conditions such as central serous chorioretinopathy, age-related macular degeneration, high myopia, vascular occlusions, and previous intraocular surgery were excluded. All eyes treated previously or concurrently with anti-VEGF agents and/or corticosteroids during the follow-up period were excluded. SD-OCT images of 22 eyes in the treatment group before treatment and at 3 months after focal laser photocoagulation, and 19 fellow treatment-naive eyes in the control group at baseline (when the fellow eye in the treatment group was treated) and at 3-month follow-up were reviewed. Two independent observers measured the choroidal thickness at 3 locations: beneath the fovea, and
500 μm temporal and 500 μm nasal to the fovea as described previously.3 The total number of focal laser treatments received in each eye (n ¼ 41) since the patients first presented until the most recent focal laser treatment were obtained from the medical charts. This study was approved by the institutional review board at Tufts Medical Center and it adhered to the tenets of the Declaration of Helsinki. All data are presented as mean ⫾ standard error of mean. Paired Student t test and Pearson correlation were used for statistical analysis. A 95% CI and a 5% level of significance were implemented; therefore, the results with a p value r0.05 were considered significant. All statistics was performed using the GraphPad Prism 5.0 for Macintosh (GraphPad Software, La Jolla, Calif).
RESULTS The 22 patients had a mean age of 54.2 ⫾ 9.9 years. There was no significant difference in the mean choroidal thickness in the treatment and control groups (n ¼ 22,
Table 1—Mean choroidal thickness at each of the 3 measured locations before and 3 months after focal laser photocoagulation in the treatment group, and at baseline and 3-month follow-up in the treatment-naive control group Mean Choroidal Thickness (μm) Location (mm from fovea) Treatment Group (n ¼ 22) CT before laser treatment CT 3 months after treatment p* Control Group (n ¼ 19) CT at baseline CT at 3-month follow-up p*
Temporal (0.5)
Fovea (0)
Nasal (0.5)
252.8 ⫾ 13.71 251 ⫾ 14.04 0.72
258 ⫾ 13.41 259.8 ⫾ 14.20 0.74
244.1 ⫾ 15.6 243.8 ⫾ 14.4 0.96
225.6 ⫾ 16.35 233.3 ⫾ 17 0.31
232.4 ⫾ 15.73 236.7 ⫾ 15.98 0.32
224.7 ⫾ 16.98 233.1 ⫾ 17.43 0.15
n, total number of eyes; CT, choroidal thickness. n
p values represent the results of the paired Student t test.
536
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Effect of focal laser therapy on the choroid—Adhi et al.
Fig. 2 — Correlation of the mean choroidal thickness with the number of focal laser treatments in 41 eyes with diabetic macular edema. Graph representing no significant association of the mean choroidal thickness with the number of laser treatments received. The p and r values represent the results of Pearson correlation.
p ¼ 0.93 and n ¼ 19, p ¼ 0.1, respectively, at 3-month follow-up (Fig. 1, Table 1). Of a total of 41 eyes with DME, 10 eyes had received 1, 12 eyes had received 2, 10 eyes had received 3, and 9 eyes had received a total of 4 focal laser treatments. There was no significant association of the number of focal laser treatments with the mean choroidal thickness (n ¼ 41, r ¼ –0.31, p ¼ 0.68; Fig. 2).
DISCUSSION Using SD-OCT, this study demonstrates that in the short-term, treatment with focal laser photocoagulation does not alter choroidal thickness in eyes with DME. Given that choroidal angiopathy has been shown to play an important role in the pathogenesis of advanced diabetic retinopathy,1–3 and current treatments for retinal diseases such as anti-VEGF agents and PDT may cause an alteration of choroidal thickness,4–7 the effects of focal laser photocoagulation on the choroid may be clinically relevant. Any treatment modality that could potentiate the deterioration of the choroid may have clinical implications in terms of disease progression and visual function. Using SD-OCT, studies have shown alterations in choroidal thickness in various diseased states, as well as the effects of various therapies used for chorioretinal diseases on the choroid.2,4–7,11–15 To our knowledge, this study is the first to assess the effect of focal laser photocoagulation on choroidal thickness. Although no alteration of choroidal thickness was observed following treatment with focal laser photocoagulation, this study is limited by a small sample size and a very short-term follow-up. A bigger sample and longer follow-up of eyes with
DME was difficult to achieve, because a large number of eyes with DME treated with focal laser photocoagulation had also received anti-VEGF therapy and/or corticosteroids either previously or concurrently during the follow-up period. Because this study was aimed to assess the effect of focal laser photocoagulation alone, other treatments would have confounded and misrepresented the sole effect of focal laser photocoagulation on the choroid. Thus, the follow-up period is short in this study. In addition, there was no association of the number of focal laser treatments to the mean choroidal thickness; however, the maximum number of laser treatments received in the eyes included in this study was only 4. Studies with long-term follow up, larger number of eyes, and eyes with DME that have received a large number of focal laser treatments may provide a better insight on the long-term effects of focal laser photocoagulation on the choroid. In conclusion, this study shows that focal laser photocoagulation does not appear to alter choroidal thickness in eyes with DME in the short term, as assessed using SD-OCT. Long-term follow-up of eyes with DME and other chorioretinal diseases treated with laser photocoagulation may provide further insight into the effects of this treatment modality on the choroid.
Disclosure: J.S.D. receives research support from Carl Zeiss Meditech, Inc, and Optovue, Inc. The remaining authors have no proprietary or commercial interest in any materials discussed in this article. Supported by: This work was supported by a Research to Prevent Blindness Unrestricted grant to the New England Eye Center, Department of Ophthalmology, Tufts University School of Medicine and by the Massachusetts Lions Eye Research Fund. REFERENCES 1. Cao J, McLeod S, Merges CA, Lutty GA. Choriocapillaris degeneration and related pathologic changes in human diabetic eyes. Arch Ophthalmol. 1998;116:589-97. 2. Fryczcowski A, Sato S, Hodes B. Changes in diabetic choroidal vasculature: scanning electron microscopy findings. Ann Ophthalmol. 1988;20:299-305. 3. Regatieri CV, Branchini L, Carmody J, et al. Choroidal thickness in patients with DR analyzed by spectral-domain optical coherence tomography. Retina. 2012;32:563-8. 4. Sayanagi K, Jo Y, Ikuno Y. Transient choroidal thinning after intravitreal bevacizumab injection for myopic choroidal neovascularization. J Clinic Experiment Ophthalmol. 2011;2:1-5. 5. Ellabban AA, Tsujikawa A, Ogino K, et al. Choroidal thickness after intravitreal ranibizumab injections for choroidal neovascularization. Clin Ophthalmol. 2012;6:837-44. 6. Maruko I, Iida T, Sugano Y, et al. Subfoveal retinal and choroidal thickness after verteporfin photodynamic therapy for polypoidal choroidal vasculopathy. Am J Ophthalmol. 2011;151:594-603. e1. 7. Branchini L, Regatieri C, Adhi M, et al. Effect of intravitreous antivascular endothelial growth factor therapy on choroidal thickness in neovascular age-related macular degeneration using spectral-domain optical coherence tomography. JAMA Ophthalmol. 2013;14:1-2http: //dx.doi.org/ doi: 10.1001/jamaophthalmol.2013.692. 8. Early Treatment of Diabetic Retinopathy Study Research Group. Photocoagulation for diabetic macular edema; Early Treatment Diabetic Retinopathy Study. Report number 1. Arch Ophthalmol. 1985;103:1796-806.
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
537
Effect of focal laser therapy on the choroid—Adhi et al. 9. Early Treatment of Diabetic Retinopathy Study Research Group. Treatment techniques and clinical guidelines for photocoagulation of diabetic macular edema. Early Treatment Diabetic Retinopathy Study. Report number 2. Ophthalmology. 1987;94: 761-74. 10. Greenstein VC, Chen H, Hood DC, et al. Retinal function in diabetic macular edema after focal laser photocoagulation. Invest Ophthalmol Vis Sci. 2000;41:3655-64. 11. Chung SE, Kang SW, Lee JH, Kim YT. Choroidal thickness in polypoidal choroidal vasculopathy and exudative age-related macular degeneration. Ophthalmology. 2011;118:840-5.
538
12. Imamura Y, Fujiwara T, Margolis R, Spaide RF. Enhanced depth imaging optical coherence tomography of the choroid in central serous chorioretinopathy. Retina. 2009;29:1469-73. 13. Maruko I, Iida T, Sugano Y, et al. Subfoveal choroidal thickness after treatment of central serous chorioretinopathy. Ophthalmology. 2010;117:1792-9. 14. Maruko I, Iida T, Sugano Y, et al. Subfoveal choroidal thickness after treatment of Vogt-Koyanagi-Harada disease. Retina. 2010;31:510-7. 15. Manjunath V, Goren J, Fujimoto JG, Duker JS. Analysis of choroidal thickness in age-related macular degeneration using spectral-domain optical coherence tomography. Am J Ophthalmol. 2011;152:663-8.
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Analysis of choroidal thickness in eyes treated with focal laser photocoagulation using SD-OCT Mehreen Adhi, MBBS, Ahmad A. Alwassia, MD, Jay S. Duker, MD ABSTRACT ● RÉSUMÉ Objective: To analyze the effect of focal laser photocoagulation on choroidal thickness in patients with diabetic macular edema (DME), using spectral-domain optical coherence tomography (SD-OCT). Design: Retrospective review. Participants: Twenty-two eyes of 22 patients diagnosed with DME and treated with focal laser photocoagulation (treatment group) and 19 fellow treatment-naive eyes (control group) who underwent high-definition 1-line raster scanning using the Cirrus SD-OCT at the New England Eye Center, Tufts Medical Center (Boston, Mass.) between November 2009 and April 2012. Methods: The SD-OCT images were analyzed for the measurement of choroidal thickness by 2 independent observers experienced in analyzing OCT images, before treatment and at 3 months after focal laser photocoagulation in the treatment group, and at baseline (when the fellow eye in the treatment group was treated) and at 3-month follow-up in the control group. Results: There was no significant difference in the mean choroidal thickness in the treatment and control groups (n ¼ 22, p ¼ 0.93 and n ¼ 19, p ¼ 0.1, respectively) at 3-month follow-up. There was no significant association of the number of focal laser treatments with the mean choroidal thickness (n ¼ 41, r ¼ 0.31, p ¼ 0.68). Conclusions: Focal laser photocoagulation does not appear to alter choroidal thickness in eyes with DME in the short term, as assessed using SD-OCT. Long-term follow-up of eyes with DME and other retinal diseases treated with laser photocoagulation may provide further insight into the effects of this treatment modality on the choroid. Objet : Analyse de l’effet de la photocoagulation focale au laser sur l’épaisseur de la choroïde chez les patients qui ont un œdème maculaire diabétique (ŒMD), à l’aide de la tomographie par cohérence optique du domaine spectral (TCO-DS). Nature : Rétrospective. Participants : Vingt-deux yeux de 22 patients ayant un diagnostic d’ŒMD et soignés par photocoagulation focale au laser (« groupe traité») et 19 yeux contralatéraux naïfs au traitement (« groupe témoin ») qui ont subi une balayage tramé d’une ligne de haute définition en utilisant la TCO-DS de Cirrus au Centre oculaire de la Nouvelle-Angleterre, du Tufts Medical Center, à Boston, entre les mois de novembre 2009 et avril 2012. Méthode : Les images de la TCO-DS ont servi à la mesure de l’épaisseur choroïdienne par deux observateurs indépendants et expérimentés dans l’analyse des images de TCO, avant le traitement et 3 mois après la photocoagulation focale au laser dans un « groupe traité », à la ligne de départ (lors du traitement de l’autre œil) et après un suivi de 3 mois dans le « groupe témoin ». Résultats : Il n’y avait pas de différence significative dans la moyenne d’épaisseur de la choroïde dans les groupes de traitement et celui des témoins (n = 22, p = 0,93 et n = 19, p = 0,1 respectivement) après trois mois de suivi. I l n’y avait pas d’association significative entre le nombre de traitements focaux au laser et l’épaisseur moyenne de la choroïde (n = 41, r = 0,31, p = 0,68). Conclusion : La photocoagulation focale au laser ne semble pas modifier l’épaisseur de la choroïde des yeux ayant un ŒMD à court terme, tel qu’évalué par TCO-DS. Le suivi à long terme des yeux atteints de l’ŒMD et d’autres maladies de la rétine, et soignés par photocoagulation au laser peut aider à voir davantage les effets de cette modalité de traitement de la choroïde.
Choroidal vascular damage plays an important role in the pathogenesis of advanced diabetic retinopathy.1–3 Current treatments for chorioretinal diseases, such as anti–vascular endothelial growth factor (anti-VEGF) agents and photodynamic therapy (PDT), have been shown to cause an alteration in choroidal thickness.4–7 Although there is conflicting evidence on the effects of anti-VEGF agents on choroidal thickness,4–6 PDT has been shown to cause a significant reduction in the choroidal thickness.7 Focal laser photocoagulation is a much more focal treatment, when compared with anti-VEGF agents and PDT, and is used as a standard for the treatment of diabetic macular edema (DME).8,9 Changes in retinal function have been demonstrated after focal laser photocoagulation in DME.10 To our knowledge, the effects of focal laser photocoagulation
on the choroid have not been evaluated to date. This study aimed to assess the effects of focal laser photocoagulation on choroidal thickness in eyes with DME, using spectral-domain optical coherence tomography (SD-OCT).
From the New England Eye Center, Tufts Medical Center, Boston, Mass.
Can J Ophthalmol 2013;48:535–538 0008-4182/13/$-see front matter & 2013 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jcjo.2013.05.010
Originally received Mar. 28, 2013. Accepted May 17, 2013
METHODS A retrospective review identified 22 eyes of 22 patients diagnosed with DME and treated with focal laser photocoagulation (treatment group), and 19 fellow treatmentnaive eyes (control group) who underwent high-definition 1-line raster scanning using the Cirrus SD-OCT at the New England Eye Center, Tufts Medical Center (Boston, Mass.) between November 2009 and April 2012.
Correspondence to Jay S. Duker, MD, New England Eye Center, Tufts Medical Center, 800 Washington Street, Boston, MA 02111; [email protected] CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
535
Effect of focal laser therapy on the choroid—Adhi et al.
Fig. 1 — Effect of focal laser photocoagulation on choroidal thickness (CT). A, Graph representing mean CT at all locations before and 3 months after focal laser photocoagulation (n ¼ 22, treatment group). B, Graph representing mean CT at all locations at baseline and at 3-month follow-up (n ¼ 19, control group). The p values represent the results of paired Student t test; n represents the number of eyes. 0.5, mm from the fovea.
SD-OCT scanning was performed using Cirrus highdefinition 1-line raster (Carl Zeiss Meditec Inc, Dublin, Calif.), which is a 6-mm line scan consisting of 4096 A-scans, an imaging speed of 27 000 A-scans per second, and a 5-μm resolution. The enhanced depth imaging function which theoretically improves visualization of the choroid, was not available at the time these scans were obtained. All scans had an intensity of 6/10 or greater and were taken as close to the fovea as possible to image the thinnest point of the macula. Patients with concomitant ocular conditions such as central serous chorioretinopathy, age-related macular degeneration, high myopia, vascular occlusions, and previous intraocular surgery were excluded. All eyes treated previously or concurrently with anti-VEGF agents and/or corticosteroids during the follow-up period were excluded. SD-OCT images of 22 eyes in the treatment group before treatment and at 3 months after focal laser photocoagulation, and 19 fellow treatment-naive eyes in the control group at baseline (when the fellow eye in the treatment group was treated) and at 3-month follow-up were reviewed. Two independent observers measured the choroidal thickness at 3 locations: beneath the fovea, and
500 μm temporal and 500 μm nasal to the fovea as described previously.3 The total number of focal laser treatments received in each eye (n ¼ 41) since the patients first presented until the most recent focal laser treatment were obtained from the medical charts. This study was approved by the institutional review board at Tufts Medical Center and it adhered to the tenets of the Declaration of Helsinki. All data are presented as mean ⫾ standard error of mean. Paired Student t test and Pearson correlation were used for statistical analysis. A 95% CI and a 5% level of significance were implemented; therefore, the results with a p value r0.05 were considered significant. All statistics was performed using the GraphPad Prism 5.0 for Macintosh (GraphPad Software, La Jolla, Calif).
RESULTS The 22 patients had a mean age of 54.2 ⫾ 9.9 years. There was no significant difference in the mean choroidal thickness in the treatment and control groups (n ¼ 22,
Table 1—Mean choroidal thickness at each of the 3 measured locations before and 3 months after focal laser photocoagulation in the treatment group, and at baseline and 3-month follow-up in the treatment-naive control group Mean Choroidal Thickness (μm) Location (mm from fovea) Treatment Group (n ¼ 22) CT before laser treatment CT 3 months after treatment p* Control Group (n ¼ 19) CT at baseline CT at 3-month follow-up p*
Temporal (0.5)
Fovea (0)
Nasal (0.5)
252.8 ⫾ 13.71 251 ⫾ 14.04 0.72
258 ⫾ 13.41 259.8 ⫾ 14.20 0.74
244.1 ⫾ 15.6 243.8 ⫾ 14.4 0.96
225.6 ⫾ 16.35 233.3 ⫾ 17 0.31
232.4 ⫾ 15.73 236.7 ⫾ 15.98 0.32
224.7 ⫾ 16.98 233.1 ⫾ 17.43 0.15
n, total number of eyes; CT, choroidal thickness. n
p values represent the results of the paired Student t test.
536
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
Effect of focal laser therapy on the choroid—Adhi et al.
Fig. 2 — Correlation of the mean choroidal thickness with the number of focal laser treatments in 41 eyes with diabetic macular edema. Graph representing no significant association of the mean choroidal thickness with the number of laser treatments received. The p and r values represent the results of Pearson correlation.
p ¼ 0.93 and n ¼ 19, p ¼ 0.1, respectively, at 3-month follow-up (Fig. 1, Table 1). Of a total of 41 eyes with DME, 10 eyes had received 1, 12 eyes had received 2, 10 eyes had received 3, and 9 eyes had received a total of 4 focal laser treatments. There was no significant association of the number of focal laser treatments with the mean choroidal thickness (n ¼ 41, r ¼ –0.31, p ¼ 0.68; Fig. 2).
DISCUSSION Using SD-OCT, this study demonstrates that in the short-term, treatment with focal laser photocoagulation does not alter choroidal thickness in eyes with DME. Given that choroidal angiopathy has been shown to play an important role in the pathogenesis of advanced diabetic retinopathy,1–3 and current treatments for retinal diseases such as anti-VEGF agents and PDT may cause an alteration of choroidal thickness,4–7 the effects of focal laser photocoagulation on the choroid may be clinically relevant. Any treatment modality that could potentiate the deterioration of the choroid may have clinical implications in terms of disease progression and visual function. Using SD-OCT, studies have shown alterations in choroidal thickness in various diseased states, as well as the effects of various therapies used for chorioretinal diseases on the choroid.2,4–7,11–15 To our knowledge, this study is the first to assess the effect of focal laser photocoagulation on choroidal thickness. Although no alteration of choroidal thickness was observed following treatment with focal laser photocoagulation, this study is limited by a small sample size and a very short-term follow-up. A bigger sample and longer follow-up of eyes with
DME was difficult to achieve, because a large number of eyes with DME treated with focal laser photocoagulation had also received anti-VEGF therapy and/or corticosteroids either previously or concurrently during the follow-up period. Because this study was aimed to assess the effect of focal laser photocoagulation alone, other treatments would have confounded and misrepresented the sole effect of focal laser photocoagulation on the choroid. Thus, the follow-up period is short in this study. In addition, there was no association of the number of focal laser treatments to the mean choroidal thickness; however, the maximum number of laser treatments received in the eyes included in this study was only 4. Studies with long-term follow up, larger number of eyes, and eyes with DME that have received a large number of focal laser treatments may provide a better insight on the long-term effects of focal laser photocoagulation on the choroid. In conclusion, this study shows that focal laser photocoagulation does not appear to alter choroidal thickness in eyes with DME in the short term, as assessed using SD-OCT. Long-term follow-up of eyes with DME and other chorioretinal diseases treated with laser photocoagulation may provide further insight into the effects of this treatment modality on the choroid.
Disclosure: J.S.D. receives research support from Carl Zeiss Meditech, Inc, and Optovue, Inc. The remaining authors have no proprietary or commercial interest in any materials discussed in this article. Supported by: This work was supported by a Research to Prevent Blindness Unrestricted grant to the New England Eye Center, Department of Ophthalmology, Tufts University School of Medicine and by the Massachusetts Lions Eye Research Fund. REFERENCES 1. Cao J, McLeod S, Merges CA, Lutty GA. Choriocapillaris degeneration and related pathologic changes in human diabetic eyes. Arch Ophthalmol. 1998;116:589-97. 2. Fryczcowski A, Sato S, Hodes B. Changes in diabetic choroidal vasculature: scanning electron microscopy findings. Ann Ophthalmol. 1988;20:299-305. 3. Regatieri CV, Branchini L, Carmody J, et al. Choroidal thickness in patients with DR analyzed by spectral-domain optical coherence tomography. Retina. 2012;32:563-8. 4. Sayanagi K, Jo Y, Ikuno Y. Transient choroidal thinning after intravitreal bevacizumab injection for myopic choroidal neovascularization. J Clinic Experiment Ophthalmol. 2011;2:1-5. 5. Ellabban AA, Tsujikawa A, Ogino K, et al. Choroidal thickness after intravitreal ranibizumab injections for choroidal neovascularization. Clin Ophthalmol. 2012;6:837-44. 6. Maruko I, Iida T, Sugano Y, et al. Subfoveal retinal and choroidal thickness after verteporfin photodynamic therapy for polypoidal choroidal vasculopathy. Am J Ophthalmol. 2011;151:594-603. e1. 7. Branchini L, Regatieri C, Adhi M, et al. Effect of intravitreous antivascular endothelial growth factor therapy on choroidal thickness in neovascular age-related macular degeneration using spectral-domain optical coherence tomography. JAMA Ophthalmol. 2013;14:1-2http: //dx.doi.org/ doi: 10.1001/jamaophthalmol.2013.692. 8. Early Treatment of Diabetic Retinopathy Study Research Group. Photocoagulation for diabetic macular edema; Early Treatment Diabetic Retinopathy Study. Report number 1. Arch Ophthalmol. 1985;103:1796-806.
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
537
Effect of focal laser therapy on the choroid—Adhi et al. 9. Early Treatment of Diabetic Retinopathy Study Research Group. Treatment techniques and clinical guidelines for photocoagulation of diabetic macular edema. Early Treatment Diabetic Retinopathy Study. Report number 2. Ophthalmology. 1987;94: 761-74. 10. Greenstein VC, Chen H, Hood DC, et al. Retinal function in diabetic macular edema after focal laser photocoagulation. Invest Ophthalmol Vis Sci. 2000;41:3655-64. 11. Chung SE, Kang SW, Lee JH, Kim YT. Choroidal thickness in polypoidal choroidal vasculopathy and exudative age-related macular degeneration. Ophthalmology. 2011;118:840-5.
538
12. Imamura Y, Fujiwara T, Margolis R, Spaide RF. Enhanced depth imaging optical coherence tomography of the choroid in central serous chorioretinopathy. Retina. 2009;29:1469-73. 13. Maruko I, Iida T, Sugano Y, et al. Subfoveal choroidal thickness after treatment of central serous chorioretinopathy. Ophthalmology. 2010;117:1792-9. 14. Maruko I, Iida T, Sugano Y, et al. Subfoveal choroidal thickness after treatment of Vogt-Koyanagi-Harada disease. Retina. 2010;31:510-7. 15. Manjunath V, Goren J, Fujimoto JG, Duker JS. Analysis of choroidal thickness in age-related macular degeneration using spectral-domain optical coherence tomography. Am J Ophthalmol. 2011;152:663-8.
CAN J OPHTHALMOL — VOL. 48, NO. 6, DECEMBER 2013
