Comparison of the Efficacy of Sub-Tenon versus Intravitreal Triamcinolone Acetonide Injection during Cataract Surgery for Diabetic Macular Edema.

PURPOSE: We compared the efficacy of sub-Tenon triamcinolone acetonide (STTA) to intravitreal triamcinolone aceto-nide (IVTA) injections during cataract surgery (CS) for patients with diabetic macular edema (DME). METHODS: The medical records of 33 eyes (26 patients) with DME which had undergone CS with STTA were compared to those of 34 eyes (27 patients) with DME which had undergone CS with IVTA. Central foveal thickness and best-corrected visual acuity (BCVA) were measured at the baseline and 1, 3, and 6 months after the surgery. RESULTS: The BCVAs after STTA and IVTA were significantly improved at 3 and 6 months. Thirteen eyes in the IVTA group and 21 eyes in the STTA group required other therapies (p < 0.05). One case developed intraocular pressure elevation after IVTA and underwent selective la ser trabeculoplasty. CONCLUSIONS: Ophthalmologists should consider the merits and demerits of IVTA and STTA for DME treatment after CS.

Comparisons of Efficacy of Intravitreal Aflibercept and Ranibizumab in Eyes with Diabetic Macular Edema.

We compared the efficacy of intravitreal aflibercept (IVA) to intravitreal ranibizumab (IVR) injections in eyes with diabetic macular edema (DME). The medical records of 49 eyes of 36 patients who were diagnosed with DME and had received IVR and 46 eyes of 40 patients who had received IVA treatment were reviewed. The central macular thickness (CMT) and best-corrected visual acuity (BCVA) were measured at the baseline and at 1, 3, and 6 months after the IVR or IVA. The mean number of injections of IVR was 2.6 ± 1.1 and of IVA was 2.7 ± 1.4. At 6 months, the CMT was significantly thinner than the baseline after IVR and after IVA. The mean BCVA was significantly better than the baseline after IVR only at 1 and 3 months and after IVA at 1 and 6 months. The BCVA of eyes with serous retinal detachment (SRD) was significantly better at 1 month after the IVR and at 1 month and 6 months after the IVA. The BCVAs improved more significantly in the SRD+ group than in the SRD- group. The effects of IVA persist longer than that of IVR. The effectiveness of both IVR and IVA was not dependent on the presence of SRD (IRB#2107).

Efficacy of One-Year Treatment with Aflibercept for Diabetic Macular Edema with Practical Protocol.

The purpose of this study was to determine the efficacy of one-year treatment of diabetic macular edema (DME) with intravitreal aflibercept (IVA) injections on a practical protocol. The medical records of 51 eyes of 43 patients who were diagnosed with DME and had received IVA treatments were reviewed. The best-corrected visual acuity (BCVA) and the central macular thickness (CMT) were measured at the baseline and at 1, 3, 6, and 12 months after the IVA. The mean number of IVA injections was 3.8 ± 2.4. The mean BCVA was significantly better and the CMT was thinner after the IVA at all follow-up times (P < 0.05). The BCVA was better in eyes with a serous retinal detachment (SRD) than without a SRD (P < 0.01). There was a significant correlation between the photoreceptor outer segment (PROS) length and BCVA at the baseline and at 12 months after the IVA (P < 0.05). A fewer number of IVA injections significantly improved the BCVA and the CMT in eyes with DME after one-year treatment. IVA was more effective in the SRD+ group than in the SRD- group. The PROS length may be a predictive marker for visual outcomes after one-year treatment with IVA for DME (IRB#2272).

Functional and morphologic outcomes after reoperation for persistent idiopathic macular hole.

PURPOSE: To determine the relationship between preoperative and postoperative characteristics and visual outcomes after successful surgery for unclosed macular hole (MH). METHODS: The medical charts of 166 eyes of 161 patients who underwent vitrectomy for a MH were reviewed. The MH was not closed in 9 eyes of 9 patients after the initial surgery. The second vitrectomy with additional internal limiting membrane (ILM) peeling and gas tamponade was performed. The preoperative and postoperative best-corrected visual acuity (BCVA), optical coherence tomographic images, MH size, duration of MH before the first operation, and area of ILM peeling were studied. RESULTS: The MH was closed in all eyes after the second surgery. The BCVA significantly improved from 0.77 to 0.25 logMAR units (20/118 to 20/36, p = 0.002). The postoperative subfoveal ellipsoid zone (EZ) was distinct and continuous in 3 eyes with good visual recovery. The final BCVA was not significantly correlated with the baseline characteristics and area of ILM peeling but was correlated with the postoperative status of the EZ. CONCLUSIONS: All MHs were closed and the mean postoperative visual acuity was significantly improved. The reason for poor visual recovery was the reduced microstructural recovery after the second surgery.

Effects of cataracts on flicker electroretinograms recorded with RETeval™ system: new mydriasis-free ERG device.

BACKGROUND: The purpose of this study was to evaluate the effects of cataracts on the flicker electroretinograms (ERGs) recorded with the RETeval™ system under mydriatic-free conditions. METHODS: This was a retrospective study of 82 eyes of 60 patients with cataracts and 52 eyes of 38 patients who were pseudophakic. Flicker ERGs were recorded with the RETeval™ system (LKC Technologies, Gaithersburg, MD) under mydriatic-free condition with skin electrodes. Flicker ERGs were elicited by white light delivered at a frequency of 28.3 Hz and intensity of 8 Td-s. The implicit times and amplitudes of the ERGs recorded from the Grade 2 cataract, Grade 3 cataract, and pseudophakic groups were compared. RESULTS: The mean amplitude was significantly smaller in both cataract groups than the pseudophakic group (Grade 2 cataract vs pseudophakic group, P < 0.0001; Grade 3 cataract vs pseudophakic group, P < 0.0001; Grade 2 cataract vs Grade 3 cataract, P = 0.027). The mean implicit times was significantly longer in both cataract groups than the pseudophakic group (Grade 2 cataract vs pseudophakic group, P = 0.046; Grade 3 cataract vs pseudophakic group, P = 0.0004; Grade 2 cataract vs Grade 3 cataract, P = 0.0084). CONCLUSIONS: The results indicate that the presence of Grade 2 or more cataracts will affect both the amplitude and the implicit time of the flicker ERGs. The presence of cataracts should be taken into consideration when interpreting the flicker ERG recorded with RETeval™.

Effects of sub-Tenon's capsule triamcinolone acetonide injection combined with microaneurysm photocoagulation on diabetic macular edema.

PURPOSE: To compare the effects of sub-Tenon's capsule triamcinolone acetonide (STTA) injection to that of STTA injection combined with microaneurysm photocoagulation (MAPC; STTA + MAPC) on eyes with diabetic macular edema (DME). PATIENTS AND METHODS: The medical records of 138 eyes of 138 patients with DME treated by either STTA or STTA + MAPC were reviewed. The degree of DME was determined by the optical coherence tomographic features: patients with serous retinal detachment (SRD+; 38 eyes) and patients without SRD (non-SRD; 100 eyes). The central macular thickness (CMT) and the best-corrected visual acuity (BCVA) were measured periodically for 6 months after the treatments. RESULTS: The BCVA was significantly improved in the non-SRD group after STTA + MAPC. The CMT was significantly improved in all groups and improved considerably more in the non-SRD group than in the SRD+ group after STTA + MAPC. CONCLUSION: Our findings indicate that MAPC has an additive effect in the non-SRD type.

Correlation between N2 amplitude of multifocal ERGs and retinal sensitivity and retinal nerve fiber layer thickness in glaucomatous eyes.

PURPOSE: To determine whether there are significant correlations between the N2 amplitude of the multifocal electroretinograms (mfERGs) and the retinal sensitivity and retinal nerve fiber layer (RNFL) thickness in glaucomatous and normal eyes. METHODS: Thirty-eight glaucomatous and 11 normal eyes were studied. The mfERGs were elicited by red stimuli presented on a blue background. The responses from the central five elements within a 20° stimulated area were analyzed. The retinal sensitivity was determined by Humphrey Field Analyzer and the RNFL thickness by spectral-domain optical coherence tomography. The correlations between the N2 amplitude and the retinal sensitivity and the RNFL thickness were calculated. RESULTS: The N2 amplitude was significantly smaller in the glaucomatous eyes than the normal eyes in all areas (P < 0.05). There was a significant correlation between the N2 amplitude and the retinal sensitivity (1/Lambert linear unit) of the HFA for the superior retina (r = 0.36, P = 0.01), for the central retina (r = 0.54, P < 0.0001), and for the inferior retina (r = 0.51, P = 0.0001). There were significant correlations between the N2 amplitude and the RNFL thicknesses in the superior retina (r = 0.49, P = 0.0003), the central retina (r = 0.79, P < 0.0001), and the inferior retina (r = 0.52, P = 0.0001) for both normal and glaucomatous eyes. CONCLUSIONS: These results indicate that the activity of the retinal ganglion cells contribute to the amplitude of the N2 of the mfERGs and thus can be used as an objective monitor of retinal ganglion cell function.

Risk Factors for Refractory Diabetic Macular Oedema after Sub-Tenon's Capsule Triamcinolone Acetonide Injection.

The purpose of this study is to identify the risk factors for a recurrence or persistence of diabetic macular oedema (DME) after a sub-Tenon's capsule triamcinolone acetonide (STTA) injection. The medical records of 124 patients (124 eyes) treated by STTA were reviewed. The age, sex, HbA1c level, best-corrected visual acuity, central macular thickness, insulin use, pioglitazone use, systemic hypertension, serous retinal detachment, proteinuria, panretinal photocoagulation, microaneurysm photocoagulation (MAPC), subthreshold micropulse diode laser photocoagulation (SMDLP), cataract surgery, and history of vitrectomy were examined by logistic regression analysis. Procedures of MAPC and SMDLP were significantly associated with DME treated with STTA (P = 0.0315, P = 0.04, resp.). However, a history of vitrectomy was found to have significantly fewer recurrences or persistent DME after STTA (P = 0.0464). In conclusion, patients who required combined MAPC or SMDLP with a STTA injection had significantly higher refractoriness to STTA, but postvitrectomy may prevent the recurrence or persistence of DME after STTA injection.

Regional reduction of ganglion cell complex after vitrectomy with internal limiting membrane peeling for idiopathic macular hole.

Purpose. To determine whether the reduction of ganglion cell complex (GCC) thickness is uniform in the parafoveal region after vitrectomy with internal limiting membrane (ILM) peeling for idiopathic macular hole (MH). Methods. Thirty-nine consecutive eyes were studied. Vitrectomy was performed with ILM peeling with brilliant blue G (BBG) staining, and room air was used for an intraocular tamponade. The GCC thickness and retinal sensitivity were measured at the superior, inferior, nasal, and temporal quadrants around the fovea using spectral domain-optical coherence tomography (SD-OCT) and microperimetry (MP-1). The measurements were made at baseline, and at 3 and 6 months postoperatively. Results. In 38 of the 39 eyes, the MH was closed after the initial surgery. At three and six months, the percentage of eyes with significantly thinner GCC areas was higher at the temporal quadrant (40.5% at 3 months and 46.0% at 6 months) than that at the other quadrants (P < 0.001, P < 0.001, resp.). The retinal sensitivity was also significantly lower in the temporal area than in the other areas (15.7 dB at 3 months, P = 0.003; 15.4 dB at 6 months, P = 0.006). Conclusion. These findings indicate that the inner retina in the temporal area may be more vulnerable to surgical manipulations than the other areas.

The effect of posterior sub-Tenon's capsule triamcinolone acetonide injection to that of pars plana vitrectomy for diabetic macular edema.

PURPOSE: To compare the effect of posterior sub-Tenon's capsule triamcinolone acetonide (STTA) injection to that of pars plana vitrectomy (PPV) for diabetic macular edema (DME). PATIENTS AND METHODS: The medical records of 50 patients (52 eyes) with DME were reviewed. Twenty-six eyes underwent STTA (20 mg) and the other 26 eyes underwent vitrectomy combined with cataract surgery. The central macular thickness (CMT), measured by optical coherence tomography, and best-corrected visual acuity (BCVA) were determined before and 1, 3, and 6 months after treatment. RESULTS: The differences in the BCVA and the CMT between the STTA group and the PPV group were not significant before or at any time after the treatment. In both the STTA and PPV groups, there were significant differences between the pre-treatment CMT and BCVA at any time after treatment. CONCLUSION: We recommend STTA injection for the treatment of DME.

[Comparison of visual acuity and central macular thickness after vitrectomy for diffuse diabetic macular edema with or without preoperative treatments].

PURPOSE: To compare the surgical outcomes during pars plana vitrectomy (PPV) for diffuse diabetic macular edema (DME) with pretreatment to those without pretreatment. METHODS: The medical charts of 43 eyes of 46 patients who underwent PPV for DME were reviewed. The previously treated (Prev. Tx) group included 19 eyes of 20 patients who were pretreated with intravitreal bevacizumab, sub-Tenon injection of triamcinolone acetonide, and/or subthreshold micropulse diode laser photocoagulation before the PPV. The treatment naïve (Tx.Naïve) group included 24 eyes of 26 patients who underwent PPV alone. The central macular thickness (CMT) and best-corrected visual acuity (BCVA) were measured before treatment and 1, 3, and 6 months after. RESULTS: In both groups, BCVA at 3 and 6 months and CMT at 1 month or later were significantly better than preoperative visual acuity. CMT at 1 month or later significantly decreased from the preoperative value (p<0.05). The differences in the BCVA and CMT between the Prev. Tx and Tx.Naïve group were not significant. CONCLUSIONS: PPV either with or without preoperative treatments can significantly improve the BCVA and reduce the CMT in patients with diffuse DME.

Comparison of vitrectomy with brilliant blue G or indocyanine green on retinal microstructure and function of eyes with macular hole.

PURPOSE: To evaluate the microstructure of the inner and outer retina and the visual function after macular hole (MH) surgery using brilliant blue G (BBG) or indocyanine green (ICG) to make the internal limiting membrane (ILM) more visible. DESIGN: Comparative, retrospective, interventional case series. PARTICIPANTS: Sixty-three eyes of 63 consecutive cases with MH were studied. Thirty-five eyes of 35 cases were treated with BBG between January and August 2011. Twenty-eight eyes of 28 MH cases were treated with ICG from April 2009 through April 2010. METHODS: Vitrectomy was performed with a 23-gauge system and 0.25 mg/ml BBG or with 0.125% ICG. MAIN OUTCOME MEASURES: The best-corrected visual acuity (BCVA) and the microperimetry-determined retinal sensitivity were measured at baseline and at 3 and 6 months after surgery. The length of the defect of the photoreceptor inner segment/outer segment (IS/OS) junction and external limiting membrane (ELM), the central foveal thickness (CFT), and the thickness of the ganglion cell complex (GCC) were measured in the spectral-domain optical coherence tomographic images. RESULTS: The average BCVA was significantly better in the BBG group than in the ICG group at 3 months (P = 0.021) and 6 months (P = 0.045) after surgery. The mean retinal sensitivity in the BBG group was improved significantly in the central 2° at 3 and 6 months (P = 0.001 and P = 0.030, respectively), but was not significantly improved in the adjacent 10°. The length of IS/OS junction defect was significantly shorter in the BBG group at 3 months (P = 0.048), but was not significantly different at 6 months (P = 0.135). The length of ELM defect and the GCC thickness were not significantly different between the 2 groups at 3 and 6 months. The CFT was significantly thinner in the ICG group than in the BBG group at 3 and 6 months (P = 0.013 and P = 0.001, respectively). CONCLUSIONS: The postoperative BCVA and retinal sensitivity in the central 2° were better in eyes after BBG-assisted vitrectomy. The restoration of IS/OS junction was faster in the BBG group, and the CFT was significantly thinner in eyes after ICG. Brilliant blue G may be a better agent than ICG to make the ILM more visible. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Outer retinal thickness and retinal sensitivity in macula-off rhegmatogenous retinal detachment after successful reattachment.

PURPOSE: To determine the relationship between the retinal thickness and sensitivity of the macular region after successful reattachment of an acute macula-off rhegmatogenous retinal detachment (RRD). METHODS: Twenty-three eyes of 23 patients with an acute macula-off RRD were studied (17 men, 6 women). The mean age of the patients was 53.2±14.7 years with a range from 20 to 73 years. The interval between the decrease in vision and surgery was <14 days in all cases. At 3 and 6 months after the surgery, the thickness of the inner and outer retina was determined by spectral-domain optical coherence tomography, and the retinal sensitivity was measured by microperimetry with MP-1. The values were compared to those obtained from the unaffected fellow eyes. Changes in the best-corrected visual acuity (BCVA), retinal thickness, and retinal sensitivity at 3 and 6 months from the baseline values were studied. RESULTS: Ten eyes were treated by scleral buckling (SB) and 13 eyes by pars plana vitrectomy (PPV), and the retina was reattached in all eyes. The mean BCVA was significantly improved at 3 and 6 months postoperatively (p<0.001, <0.001). The outer retina of macula was significantly thicker after SB than after PPV (p=0.023 at 3 months; p=0.045 at 6 months). The retinal sensitivity of the central 10 degrees of the retinas after SB was lower than that of eyes after PPV (p=0.029 at 3 months and p=0.008 at 6 months). CONCLUSIONS: The delay in the recovery of outer retinal thickness may be the cause of the lower sensitivity of the macula.

Development of macular holes after rhegmatogenous retinal detachment repair in Japanese patients.

Purpose. To determine the factors associated with the development of a macular hole (MH) after successful rhegmatogenous retinal detachment (RRD) surgery. Methods. Of 1260 eyes that underwent surgery for RRD between April 2005 and March 2010 in our hospital, the medical records of 4 cases from our hospital and one case from another hospital that had undergone RRD surgery and later developed MH were reviewed. This is a retrospective study. Results. 837 eyes underwent pars plana vitrectomy (PPV) with or without scleral buckling (SB), and 423 eyes underwent SB. The four cases that developed MH had PPV alone and one case had PPV with SB. After including the results of three earlier reports, the mean interval for the MH to develop after SB alone was significantly shorter than after PPV alone or after PPV with SB. Conclusions. The SB procedures might accelerate the development of MH after RRD surgery.

[Six cases of sterile endophthalmitis developed consecutively after intravitreal injection of bevacizumab].

PURPOSE: To report a series of 6 cases of sterile endophthalmitis that developed consecutively after an intravitreal injection of bevacizumab (IVB). PATIENTS AND METHODS: On April 13 and 14, 2009, we performed IVB for consecutive 12 eyes of 12 patients in a sterile condition. Within two days after injection, blurred vision without ocular pain, anterior chamber inflammation, and vitreous opacity were developed in 6 of the eyes of 6 patients. Hypopyon was not observed in any patient. Anterior chamber fluid from each eye and all syringes of bevacizumab that have been separated from the same bottle of same lot number were sent for bacterial culture examination. RESULTS: No bacterial colony was developed from the anterior chamber fluid of any of the patients nor from any of the syringes. Antibiotic treatment of all 6 patients was unsuccessful. The symptoms improved in all cases following treatment with topical corticosteroid within several days. CONCLUSIONS: Both the clinical course and the results of bacterial culture, lead to the possibility that our patients developed sterile endophthalmitis rather than infectious endophthalmitis. The exact causes of the endophthalmitis were not identified in our cases, but similar events are reported by several institutions, endophthalmitis following IVB needs to be considered a possibility.

Relationship between vision-related quality of life and microperimetry-determined macular sensitivity in patients with retinitis pigmentosa.

PURPOSE: The aim of our study was to determine the relationship between vision-related quality of life (VRQOL) following the National Eye Institute Visual Function Questionnaire-25 (NEI VFQ-25) and the macular sensitivity determined by microperimetry in patients with retinitis pigmentosa (RP). METHODS: The Japanese version of the NEI VFQ-25 was used to assess the VRQOL of 30 patients with typical RP whose decimal visual acuity was ≥0.6. The mean retinal sensitivity within the central 10° was determined by fundus-related microperimetry (MP1). The correlation between the mean of the total composite NEI VFQ-25 score and MP1-determined macular sensitivity was determined. RESULTS: Mean NEI VFQ-25 score was 69.4 ± 14.5 (range 34.6-90.3) in RP patients. There was a significant positive correlation between mean NEI VFQ-25 score and mean retinal sensitivity within 10° (r = 0.673, P = 0.0003). CONCLUSION: The significant correlation between macular sensitivity and VRQOL measured with the NEI VFQ-25 indicates that sensitivity in the macular area is an important consideration in using VRQOL with RP patients.

Vitrectomy alone versus vitrectomy with simultaneous intravitreal injection of triamcinolone for macular edema associated with branch retinal vein occlusion.

BACKGROUND AND OBJECTIVE: To evaluate the efficacy of vitrectomy with simultaneous intravitreal injection of triamcinolone acetonide for macular edema associated with branch retinal vein occlusion. PATIENTS AND METHODS: A retrospective study of 45 eyes with macular edema associated with branch retinal vein occlusion. A posterior vitreous detachment was created and the vitreous cortex was completely removed, after which 23 eyes immediately had an intravitreal injection of triamcinolone acetonide (triamcinolone acetonide group) and 22 eyes did not (no triamcinolone acetonide group). Visual acuity, fluorescein angiograms, and foveal thickness determined by optical coherence tomography were examined preoperatively and postoperatively. RESULTS: Mean postoperative visual acuity at 12 months was significantly better than the preoperative visual acuity in both groups. The fovea was significantly thinner 1 month postoperatively in both groups. Foveal thickness gradually decreased until 12 months in the no triamcinolone acetonide group; however, foveal thickness increased for 12 months in the triamcinolone acetonide group. A recurrence of macular edema was more frequent in the triamcinolone acetonide group than in the no triamcinolone acetonide group (P = .006). CONCLUSIONS: Because there was no significant difference in the improvement of best-corrected visual acuity between the groups 12 months postoperatively, there may be no benefit in the use of intraoperative intravitreal triamcinolone acetonide.

Efficacy of vitrectomy and internal limiting membrane removal for macular edema associated with branch retinal vein occlusion.

AIM: To compare the results of vitrectomy with internal limiting membrane (ILM) peeling to that without ILM peeling for macular edema associated with branch retinal vein occlusion (BRVO). METHODS: The medical records of 47 eyes of 47 patients with BRVO-associated macular edema were examined. To treat the macular edema, a posterior vitreous detachment (PVD) was created, and the ILM was removed in 13 eyes (ILM-removed group), whereas a PVD was created and the ILM was not removed in 34 eyes (ILM-preserved group). The best-corrected visual acuity (BCVA) and the optical-coherence-tomography-determined foveal thickness were obtained preoperatively and at 6 months postoperatively. RESULTS: The mean postoperative BCVA was significantly better than the preoperative BCVA in both the ILM-removed and in the ILM-preserved groups (p = 0.0017 and p = 0.0002, respectively). The fovea was significantly thinner at 1 month after surgery in both groups (p = 0.0007 and p < 0.0001, respectively). The postoperative improvement of the mean BCVA and the foveal thickness were not significantly different for the two groups at any postoperative period. CONCLUSIONS: Because there was no significant difference in the improvement of BCVA between the two groups at 6 months postoperatively, there may be no additional benefit in removing the ILM for BRVO-associated macular edema.

Sodium azide induces necrotic cell death in rat squamous cell carcinoma SCC131.

Sodium azide (NaN(3)) is widely used in industry and agriculture, and also in laboratories as a potent preservative. NaN(3) induces cell death when applied to cultured cells. However, whether the mode of cell death is apoptosis or necrosis remains a subject of debate. There have been no previous reports on NaN(3)-induced cell death in squamous cell carcinoma (SCC), and so we studied the mode of cell death induced by NaN(3) using the rat SCC cell line, SCC131. In this experiment, SCC131 cells died 48-72 h after NaN(3) treatment with concentrations greater than 5 mM. The NaN(3) treatment reduced the mitochondrial membrane potential and ATP content. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and DNA ladder detection assay indicated that no DNA fragmentation occurred. In addition, phosphatidyl serine did not appear on the cell surface, according to the findings of dye-uptake bioassay and flow cytometric analysis of Annexin V labeling. Electron microscopic analysis revealed that the NaN(3)-treated cells showed mitochondrial swelling and rupture of the cell membrane. In conclusion, NaN(3) induces necrotic cell death in SCC131. This experimental model may be used in the study of necrotic cell death.

Changes of electroretinogram without improvement of retinal circulation after radial optic neurotomy for central retinal vein occlusion. ERG changes after RON for CRVO.

PURPOSE: To evaluate the efficacy of radial optic neurotomy (RON) on retinal function in patients with central retinal vein occlusion (CRVO). METHODS: Ten eyes of 10 patients with CRVO underwent pars plana vitrectomy and RON. Standardized combined electroretinograms (ERGs) to full-field bright-flash stimuli were recorded preoperatively and, 3 months postoperatively. The best-corrected visual acuity and foveal thickness were also determined, before and 3 months postoperatively. RESULTS: The mean best-corrected visual acuity and mean foveal thickness were both significantly improved after vitrectomy and RON. The mean amplitudes of a- and b-waves did not change significantly, but the mean b/a wave ratio was increased significantly after vitrectomy and RON. An improvement of the b/a ratio was observed in six eyes, however, an improvement of retinal circulation was confirmed on postoperative fluorescein angiograms in two of these six eyes. CONCLUSIONS: Significant improvements were observed in the b/a wave ratio of the standard combined ERGs after surgery in eyes with CRVO. The improvement of retinal function was most likely due to improved oxygenation of retina caused by vitrectomy and not by RON.