2012, Number 1
PDF size: 260.10 Kb.
ABSTRACTBackground: Optical coherence tomography (OCT) quantifies changes of foveal thickness and macular volume after photocoagulation in diabetic macular edema. Macular volume evaluates the whole macula, but it may underestimate changes in foveal thickness induced by photocoagulation. We undertook this study to evaluate the concordance between macular volume and foveal thickness for identifying clinically significant changes of retinal thickness after photocoagulation for diabetic macular edema.
Methods: We carried out an observational, prospective, longitudinal, analytical study. Center point thickness (CPT), central subfield mean thickness (CSMT) and macular volume were measured with OCT before photocoagulation and 3 weeks after in diabetic patients with focal macular edema (January 2006–January 2010). Concordance among variables to detect clinically significant changes (CPT ›17%, CSMT ›11%, macular volume ›3%) was identified using the kappa test.
Results: Sixty eight eyes were included; 47 eyes had nonproliferative retinopathy (69.1%). CPT increased significantly in 14.7% of the sample; CSMT in 8.8%, and macular volume in 11.8%. CPT decreased significantly in 4.4%, CSMT in 8.8%, and macular volume in 42.6%. Concordance was regular for CPT and CSMT increased (57%). Concordance was good for CPT and CSMT decreased (64%). Concordance was regular for CSMT and macular volume decreased in eyes with center involvement (43%). The remaining concordances were poor.
Discussion: Two independent events happen after focal photocoagulation: involution of the original thickening and increase in CPT. In order to detect both events, evaluation of either foveal thickness alone or macular volume alone is insufficient.
Conclusion: Identifying the efficacy and safety of treatments for diabetic macular edema requires simultaneous measurement of CPT and macular volume.
Cheung N, Mitchell P, Wong TY. Diabetic retinopathy. Lancet 2010;376:124-136.
American Academy of Ophthalmology, Retina Panel. Diabetic Retinopathy. Preferred practice patterns. San Francisco: American Academy of Ophthalmology, 2008. p. 13.
Bhagat N, Grigorian RA, Tutela A, Zarbin MA. Diabetic macular edema: pathogenesis and treatment. Surv Ophthalmol 2009;54:1-32.
Nonaka A, Kiryu J, Tusjikawa A, Yamashiro K, Nishijima K, Kamizuru H, et al. Inflammatory response after scatter laser photocoagulation in nonphotocoagulated retina. Inv Ophthalmol Vis Sci 2002;43:1204-1209.
Alasil T, Keane PA, Updike JF, Dustin L, Ouyang Y, Walsh AC, et al. Relationship between optical coherence tomography retinal parameters and visual acuity in diabetic macular edema. Ophthalmology 2010;117:2379-2386.
Voo I, Mavrofrides EC, Puliafito CA. Clinical applications of optical coherence tomography for the diagnosis and management of macular diseases. Ophthalmol Clin North Am 2004;17:21-31.
Polito A, Del Borrello M, Isola M, Zemella N, Bandello F. Repeatability and reproducibility of fast macular thickness mapping with Stratus optical coherence tomography. Arch Ophthalmol 2005;123:1330-1337.
Muquit MMK, Gray JCB, Marcellino GR, Henson DB, Young LB, Patton N, et al. Barely visible 10-millisecond Pascal laser photocoagulation for diabetic macular edema: observations of clinical effect and burn localization. Am J Ophthalmol 2010;149:979-986.
Browning DJ, Glassman AR, Aiello LP, Beck RW, Brown DM, Fong DS, et al. Diabetic Retinopathy Clinical Research Network. Relationship between optical coherence tomography-measured central retinal thickness and visual acuity in diabetic macular edema. Ophthalmology 2007;114:525-536.
Krzystolik MG, Strauber SF, Aiello LP, Beck RW, Berger BB, Bressler NM, et al. Reproducibility of macular thickness and volume using Zeiss optical coherence tomography in patients with diabetic macular edema. Ophthalmology 2007;114:1520-1525.
Browning DJ, Glassman AR, Aiello LP, Bressler NM, Bressler SB, Danis RP, et al. Optical coherence tomography measurements and analysis methods in optical coherence tomography studies of diabetic macular edema. Ophthalmology 2008;115:1366-1371.
Shimura M, Yasuda K, Nakazawa T, Kano T, Ohta S, Tamai M. Quantifying alterations of macular thickness before and after panretinal photocoagulation in patients with severe diabetic retinopathy and good vision. Ophthalmology 2003;110:2386-2394.
Sandhu SS, Birch MK, Griffiths PG, Talks SJ. Short-term effects of focal argon laser treatment in diabetic maculopathy as demonstrated by optical coherence tomography. Retina 2007;27:13-20.
Sadda SR, Wu Z, Walsh AC, Richine L, Dougall J, Cortez R, et al. Errors in retinal thickness measurements obtained by optical coherence tomography. Ophthalmology 2006;113:285-293.
Lima-Gómez V, Osornio-Castro NA. Comparación del grosor retiniano en diabéticos sin retinopatía, con y sin fondo coroideo. Rev Mex Oftalmol 2006;80:301-305.
Chan A, Duker JS. A standardized method for reporting changes in macular thickening using optical coherence tomography. Arch Ophthalmol 2005;123:939-943.
Scott IU, Danis RP, Bressler SB, Bressler NM, Browning DJ, Qin H, et al. Effect of focal/grid photocoagulation in visual acuity and retinal thickening in eyes with non-center-involved diabetic macular edema. Retina 2009;29:613-617.
Toth CA, Birngruber R, Boppart S, Hee MR, Fujimoto JG, DiCarlo CD, et al. Argon laser retinal lesions evaluated in vivo by optical coherence tomography. Am J Ophthalmol 1997;123:188-198.