Purpose To compare optical coherence tomography (OCT) and confocal scanning la ser tomography (cSLT) for quantitative retinal thickness mapping of the macula a nd their ability to detect macular edema. Design Prospective, comparative, clini cal observational study. Methods The study population of 138 eyes (97 patients) was divided into a study group consisting of 45 (32.6%) eyes with macular edema and a control group consisting of 93 (67.4%) eyes without macular edema. All p atients underwent OCT and cSLT of the macula. Retinal thickness measurements obt ained by OCT were compared with signal width and edema index, determined by cSLT . Results The OCT measurements and cSLT edema index were significantly (P< 0 .00 1) correlated with each other. Correlation coefficients decreased (P< 0.001)with increasing diameter of the measurement circle. In the macular edema group, corr elation coefficients were significantly (P< 0.001) higher than in the control gr oup. To separate the study and control groups, receiver operator characteristic curves covered a larger area for OCT measurements than for cSLT measurements. Re tinal thickness measurements and edema index correlate with visual acuity (corre lation coefficient r=-0.653 for OCT, r=-0.608 for cSLT; P < .001). Conclusions Macular edema can be quantitatively mapped by OCT and cSLT. The retinal thickne ss and edema index measurements correlate with visual acuity. The fast and stand ard examination modes of OCT give similar measurements. Both OCT and cSLT can di fferentiate between eyes with and without macular edema, with OCT showing a high er predictive value. Purpose To compare optical coherence tomography (OCT) and confocal scanning la ser tomography (cSLT) for quantitative retinal thickness mapping of the macula a nd their ability to detect macular edema. Design Prospective, comparative, clini cal observational study. Methods The study population of 138 eyes (97 patients) were divided into a study group consisting of 45 (32.6%) eyes with macular edema and a control group consisting of 93 (67.4%) eyes without macular edema. All p atients underwent OCT and cSLT of the macula. Retinal thickness measurements obtined by OCT were compared with signal width and edema index, determined by cSLT. Results The OCT measurements and cSLT edema index were significantly (P <0.001) correlated with each other. Correlation coefficients decreased ) with increasing diameter of the measurement circle. In the macular edema group, corr elation coefficients were significantly (P <0.001) higher than in the control gr oup. To separate the study and cont rol groups, receiver operator characteristic curves covered a larger area for OCT measurements than for cSLT measurements. Re tinal thickness measurements and edema index correlate with visual acuity (corre lation coefficient r = -0.653 for OCT, r = -0.608 for cSLT; P < .001). Conclusions Macular edema can be quantitatively mapped by OCT and cSLT. The retinal thickne ss and edema index measurements correlate with visual acuity. The fast and stand ard examination modes of OCT give similar similarities. Both OCT and cSLT can di fferentiate between eyes with and without macular edema, with OCT showing a high er predictive value.