1. Assessment of macular thickness and function by optical coherence tomography and multifocal electroretinogram in uncomplicated cataract surgery Yang Li, Jason Dilly, Michael Ober, Gary Trick Department of Ophthalmology, Henry Ford Hospital, Detroit, MI Authors have no financial interest

2. Purpose To determine whether there is an increase of macular thickness and /or impairment of photoreceptor function in patients following uncomplicated cataract surgery. To determine whether there is an association between changes in macular thickness and photoreceptor function.

3. Methods Prospective study 12 patients undergoing uneventful small– incisional cataract surgery Patient’s mean age: 69 years Pre-op evaluation and post-op evaluation at 2 weeks & 3 months - Complete ophthalmic examination - Complete ophthalmic examination - OCT (Stratus 3) - OCT (Stratus 3) - mfERG (Veris 5.0.5): the mfERG responses were analyzed within the 3 central concentric rings which correspond to the foveal and parafoveal area measured by the OCT - mfERG (Veris 5.0.5): the mfERG responses were analyzed within the 3 central concentric rings which correspond to the foveal and parafoveal area measured by the OCT

4. Results: Post-op 2 weeks OCT - Pre-op central retinal thickness was 221.3 ± 4.7µm (mean ± standard error of mean [SEM]). - Pre-op central retinal thickness was 221.3 ± 4.7µm (mean ± standard error of mean [SEM]). - In 6 of 12 patients (50%) retinal thickness increased by at least 2 SEM at 2 weeks post-op. In this group the central retinal thickness increased from 218.5 ± 4.1 µm to 234.9 ± 3.7 µm. - In 6 of 12 patients (50%) retinal thickness increased by at least 2 SEM at 2 weeks post-op. In this group the central retinal thickness increased from 218.5 ± 4.1 µm to 234.9 ± 3.7 µm.mfERG - Ten of 12 patients (83.33%) had an increased mfERG response (mean = 32.88%) post-op. - Ten of 12 patients (83.33%) had an increased mfERG response (mean = 32.88%) post-op. - Two of 12 patients (16.67%) had decreased mfERG response (mean = 19.8%) post-op. - Two of 12 patients (16.67%) had decreased mfERG response (mean = 19.8%) post-op.

5. OCT : mfERG - Both patients with decreased photoreceptor responses exhibited increased central retinal thickness. - Both patients with decreased photoreceptor responses exhibited increased central retinal thickness. - In patients with increased central retinal thickness the change in mfERG amplitude (20.03%) was less than in the patients with no increase in central retinal thickness (28.17%). Excluding one mfERG outlier (pre-op mfERG substantially lower than other subjects) the difference between the two groups is significantly increased (5.28% vs 28.17%). - In patients with increased central retinal thickness the change in mfERG amplitude (20.03%) was less than in the patients with no increase in central retinal thickness (28.17%). Excluding one mfERG outlier (pre-op mfERG substantially lower than other subjects) the difference between the two groups is significantly increased (5.28% vs 28.17%).

6. Pre-op: 228umPost-op: 241um A patient with increased central retinal thickness Pre-op: 237umPost-op: 240um A patient with unchanged central retinal thickness

7. Pre-opPost-op: 2 weeks A patient with decreased mfERG response 2 weeks post-op Pre-opPost-op: 2 weeks A patient with increased mfERG response 2 weeks post-op

8. Results: post-op 3 months OCT - Pre-op central retinal thickness was 221.9 ± 5.4µm (mean ± SEM). - Pre-op central retinal thickness was 221.9 ± 5.4µm (mean ± SEM). - In 3 of 6 patients (50%) retinal thickness increased by at least 2 SEM at 3 months post-op. In this group the central retinal thickness increased from 224 ± 8.7µm to 247 ± 21.6µm. - In 3 of 6 patients (50%) retinal thickness increased by at least 2 SEM at 3 months post-op. In this group the central retinal thickness increased from 224 ± 8.7µm to 247 ± 21.6µm.mfERG - Four of 6 patients (66.67%) had an increased mfERG response (mean = 22.78%) post-op. - Four of 6 patients (66.67%) had an increased mfERG response (mean = 22.78%) post-op. - Two of 6 patients (33.33%) had decreased mfERG response (mean = 8.46%) post-op. - Two of 6 patients (33.33%) had decreased mfERG response (mean = 8.46%) post-op.

9. OCT : mfERG - Both patients with decreased photoreceptor responses exhibited increased central retinal thickness. - Both patients with decreased photoreceptor responses exhibited increased central retinal thickness. - In patients with increased central retinal thickness the change in mfERG amplitude (- 1.50%) was less than in the patients with no increase in central retinal thickness (26.22%). - In patients with increased central retinal thickness the change in mfERG amplitude (- 1.50%) was less than in the patients with no increase in central retinal thickness (26.22%).

10. Conclusions Subclinical central retinal thickening occurs in many patients after uncomplicated standard small–incisional cataract surgery. In most patients, the mfERG response increases or remains unchanged after uncomplicated cataract surgery. Even mild increase in central retinal thickness on OCT (subclinical CME) may be associated with decreased retinal function as manifested by decreased mfERG amplitude.