Background
Using standardized macular optical coherence tomography (OCT) in the postoperative period, subclinical changes in macular
thickness can be detected. With this method, postoperative development of macular thickness in healthy eyes is evaluated.
The repeatability of the method and the influence of selected surgical (phaco time and phaco energy) and biometric parameters
(axial length and anterior chamber depth) on the results were assessed.
Methods
In a prospective study, 33 patients without macular pathology in both eyes were examined. Phacoemulsification and intraocular
lens (IOL) implantation was performed in one eye, and the contralateral eye served as control. OCT (StratusOCT; Zeiss, Dublin,
CA, USA), mean minimal foveal thickness (MMFT) and mean foveal thickness (MFT) were measured preoperatively, at 1 day, 1 week
and 6 weeks postoperatively.
At these visits, the best-corrected visual acuity (BCVA) tests and slit-lamp examination were performed. To assess the influence
on foveal thickness ocular axial length, anterior chamber depth, phacotime and energy were documented. Statistical analysis
using parametric tests was carried out with standard statistical software (SPSS11, BIAS).
Results
MMFT of the operated eyes and the intraindividual difference of MMFT increased significantly at one day (+12.31 ± 24.2 μm,
P < 0.001) and 6 weeks (+6.76 ± 22.6 μm, P = 0.009). MFT in the operated eyes and intraindividual difference of MFT rose significantly at 1 day, 1 week and 6 weeks
(1 day: +10.66 ± 20.8 μm, P = 0,026; 1 week: +15.23 ± 19.7 μm; 6 weeks: +17.33 ± 14.81 μm, P < 0.001). Repeatability was better for MFT in controls (ICR = 0.92) than for MMFT in controls (ICR = 0.77). No clinical cystoid
macular edema was diagnosed in this study. No correlation between macular thickening and visual acuity and selected surgical
and biometrical parameters could be found.
Conclusions
After cataract surgery, a mild increase of foveal thickness without impact on visual acuity could be observed. This increase
may be due to both subclinical changes and to influence of changes in media opacity on the measurement technique. Surgical
and biometric parameters such as phacotime and energy and axial length did not correlate to the degree of macular thickening.
Keywords Cataract surgery - Phacoemulsification - Subclinical macular edema - Optical coherence tomography - Macular thickness - Intraindividual difference - Phaco time - Phaco energy - Axial length
Presented in part at the meeting of the European Society of Cataract and Refractive Surgeons (ESCRS), London, United Kingdom,
September 2006 and at the meeting of the German Ophthalmological Society (DOG), Berlin, Germany, September 2006.
The authors have no financial or proprietary interest in any material or method mentioned.