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Background: Retinal function is transiently depressed after photodynamic therapy (PDT) alone. One of the reasons for this functional impairment is a reduction of choroidal circulation caused by the PDT. The purpose of this study was to determine whether PDT combined with intravitreal bevacizumab (PDT+IVB) can reduce or prevent the transient impaired macular function. In addition, we examined whether a significant correlation existed between the changes in the focal macular electroretinograms (FMERGs), optical coherence tomography (OCT)-determined morphology, and changes in choroidal circulation., Methods: Thirty-eight eyes that were treated by full fluence PDT+IVB were studied. FMERGs, OCT, and indocyanine green angiography (ICGA) were performed before and after the PDT. The intensity of the diffuse fluorescence within the PDT site was measured by densitometry (I/N ratio)., Results: The macula was significantly thinner 1 week after PDT+IVB (P < 0.01). The mean a- and b-wave amplitudes of the FMERGs were not significantly decreased 1 week after PDT+IVB. The mean b-wave amplitudes 3 months after PDT+IVB were significantly increased (P < 0.01). The I/N ratio of ICGA 3 months after PDT+IVB was 0.88 ± 0.1. The correlation between the FMERGs and I/N ratio was not significant., Conclusion: The use of IVB with PDT mitigates the reduction of the FMERGs and reduces the macular thickness soon after PDT, regardless of the degree of impairment of choroidal circulation caused by PDT. Finally, the macular retinal function 3 months after PDT+IVB were better than that before the treatment.

Purpose: Retinal function is commonly depressed transiently after photodynamic therapy (PDT). Additional treatment may prevent this impaired retinal function. The purpose of this study was to determine the changes in the focal macular electroretinograms (FMERGs) after PDT combined with TA for age-related macular degeneration., Methods: Thirty-four eyes that were successfully treated by PDT with a posterior juxtascleral injection of TA were studied. FMERGs, optical coherence tomography, and indocyanine green angiography were performed before and after the PDT., Results: The mean amplitudes of the FMERGs were not significantly decreased 1 week after PDT with TA (P > 0.05). The mean ratio of the FMERG b-wave 1 week after PDT to that before PDT was 1.09, with an indistinct hypofluorescence at the site of the PDT (18 eyes), and the ratio was 0.91 in the eyes with a distinct hypofluorescence border (16 eyes; P < 0.05)., Conclusion: The combined use of TA with PDT mitigated the depression of retinal function soon after PDT. However, there were cases of severe choroidal hypoperfusion corresponding to the site of the laser spot that impaired retinal function in comparison to cases with mild hypoperfusion. Even with severe choroidal hypoperfusion, the deterioration in retinal function was relatively mild, with the b-wave FMERG reduced by only 10%.

Purpose: To determine whether a significant correlation exists between the morphology of the macula measured by optical coherence tomography (OCT) and the amplitude of focal macular electroretinograms (fmERGs) in patients with retinitis pigmentosa (RP)., Methods: fmERGs were recorded in 43 patients with RP and 43 age-similar normal subjects, with a 15 degrees stimulus spot, 5.6 to 5.8 mm in diameter on the fundus. The sum of the volume of the neural retina in the central 6 mm (total macular volume) was measured with the OCT system. The length of the photoreceptor inner segment/outer segment junction (IS/OS line) in a 6-mm diameter macular area was also measured in the OCT images., Results: There was a weak correlation between the total macular volume and the fmERG amplitudes (correlation coefficient, 0.46 for the a-wave and 0.54 for the b-wave). The fmERG amplitudes in the patients with RP with IS/OS line longer than 2 mm were significantly larger than those in patients with RP with IS/OS line shorter than 2 mm, but the correlations between these two factors were weak. One major reason for the low correlations between the macular morphology and fmERGs was that there were some patients with RP who had normal macular volume and long IS/OS line, but had severely reduced focal macular ERGs., Conclusions: Although the macular volume and length of the IS/OS line correlated weakly with the amplitude of the fmERGs, a preserved macular morphology does not necessarily guarantee normal-amplitude fmERGs in patients with RP.

Purpose: To study the properties of the focal macular electroretinograms (fmERGs) in eyes with untreated wet-type age-related macular degeneration (AMD)., Methods: fmERGs were recorded from 157 eyes of 157 consecutive patients with untreated wet-type AMD (113 men, 44 women; age, 71.3 +/- 8.0 years). The fmERGs were recorded under direct fundus observation using a modified infrared fundus camera and a 15 degrees stimulus spot. Amplitudes and implicit times of the fmERGs recorded from the AMD patients were compared with those from 21 age-similar healthy controls., Results: The amplitudes of fmERGs in the AMD patients were significantly smaller (P < 0.001) and the implicit times were significantly longer (P < 0.001) than the corresponding values in the control eyes. There was a significant correlation between amplitude and implicit time of the fmERG and visual acuity (logMAR), but the degree of correlation was weak. The difference in the b/a amplitude ratio between the AMD patients and healthy controls was not significant., Conclusions: The significant reduction in amplitude and the severe delay in implicit times of a- and b-waves of the fmERGs indicated significant functional alterations in the inner and the outer retinal layers of the macular area of eyes with wet-type AMD.

Focal macular cone electroretinograms (ERGs) and multifocal ERGs were recorded to study the macular function in patients with the complete-type of congenital stationary night blindness (cCSNB). The waveforms of the focal macular cone ERGs and the on- and off-responses of the multifocal ERGs in the cCSNB patients were similar to those recorded from monkey retinas treated with L-2 amino-4-phosphonobutyric acid (APB), suggesting that patients with cCSNB have a complete defect of the on-pathway even in the central retina. The results also demonstrated that there was a paradoxical positive response in the central retina of cCSNB patients, as compared to the negative full-field ERGs in the same subjects.

Purpose: To study the functional changes in the macula of the retina in the early stage of retinitis pigmentosa (RP), by analyzing each component of the focal macular electroretinogram (fmERG)., Methods: fmERGs were recorded from 39 patients with RP with normal visual acuity (>1.0) under direct fundus observation using a modified infrared fundus camera and 5 degrees , 10 degrees , and 15 degrees stimulus spots. The amplitudes and implicit times of the a-wave, b-wave, and oscillatory potentials (OPs) in the patients with RP were compared to those from 30 age-similar normal control subjects., Results: The amplitudes of the different components of the fmERGs in patients with RP ranged from severely reduced to normal. The degree of amplitude reduction increased as the size of the stimulus spot increased in the patients with RP. The relative amplitudes of the OPs (67% of the mean in normal subjects) were better preserved than that of the b-wave (46%) and the a-wave (39%) in a 10 degrees spot in the patients with RP., Conclusions: The relative preservation of the OPs in the patients with RP could be due to either the buffering effect of the large receptive fields of the OP generators or to the retinal remodeling after the progressive loss of photoreceptors. Recordings of each component of fmERG can provide important information on the different layers of the central retina in RP eyes and can add to the understanding of the pathophysiology of RP.

Purpose: It is known that the amplitudes of the multifocal electroretinograms are generally reduced soon after photodynamic therapy (PDT). The purpose of this study was to determine whether this amplitude reduction correlates with the changes in macular thickness or with changes in choroidal circulation., Methods: Thirty-seven eyes that were successfully treated by PDT were studied. Focal macular electroretinograms (fmERGs) and optical coherence tomography were performed before and 1 week, 1 month, and 3 months after PDT. Indocyanine green angiography was performed before and 3 months after PDT. The indocyanine green angiographic findings were classified into two groups: group A, with indistinct hypofluorescence at the site of the PDT, and group B, with well-defined hypofluorescence borders coinciding with the site of the PDT., Results: The mean amplitudes of the fmERGs were significantly reduced at 1 week after PDT (P < 0.05). The correlations between the changes in the amplitude of the fmERG and the changes in macular thickness were not significant. Sixteen (43%) of the study eyes were classified into group A and 21 (57%) into group B by indocyanine green angiography. The mean ratio of the fmERG b-wave 1 week after PDT to that before PDT was 1.14 +/- 0.62 in group A and 0.65 +/- 0.29 in group B. This difference was statistically significant (P < 0.01)., Conclusions: One of the possibilities that could explain the reduction in the amplitude of the fmERGs soon after PDT is the reduction in choroidal circulation caused by the PDT.

Purpose: The photopic negative response (PhNR) is a negative component of the photopic electroretinogram (ERG) that is observed after the b-wave and is thought to originate mainly from the activity of ganglion cells and their axons. The purpose of this study was to determine whether there are subclinical functional changes in the inner retina after macular hole surgery, by recording the PhNR before and after surgery., Methods: In addition to the routine ophthalmic examinations, photopic ERGs were recorded in 16 eyes with an idiopathic macular hole, before and 3 months after surgery. Photopic ERGs were elicited by white Ganzfeld flashes on a rod-suppressing blue background. The amplitude of the PhNR and the a- and b-waves of the photopic ERGs before and after surgery were compared. PhNRs were also recorded in 14 eyes with epiretinal membrane, before and after surgery., Results: Macular holes were closed and visual acuities were improved without any serious complications in all eyes with a macular hole. The amplitude of the PhNR was significantly reduced after surgery (P < 0.05), whereas the amplitude of the photopic a- and b-waves were not significantly altered. For eyes with an epiretinal membrane, the mean amplitude of the PhNR was slightly decreased after the surgery, but the degree of reduction was only one half of that after macular hole surgery., Conclusions: These results suggest that there are some functional impairments in the inner retina after macular hole surgery, even though the patients did not show any reduction on subjective visual tests. The PhNR can be a useful clinical test to assess the inner retinal function objectively, before and after vitreoretinal surgery.

Purpose: To evaluate the effect of transpupillary thermotherapy (TTT) on foveal thickness and macular function in eyes with choroidal neovascularization (CNV) associated with age-related macular degeneration., Methods: Sixteen eyes with occult CNV and 6 eyes with classic CNV were treated with TTT. Optical coherence tomography and focal macular electroretinograms (FMERGs) elicited by a 15-degree stimulus were performed before, 3 months after TTT in 22 eyes and 6 months after TTT in 18 eyes., Results: Before TTT, the fovea in 20 of the 22 eyes with CNV was significantly thicker than that of normal subjects. The foveal thickness was reduced after TTT in 11 of 14 eyes with occult CNV and remained unchanged in 2 eyes. One eye with occult CNV before TTT developed a classic CNV with significant macular edema and increased foveal thickness 3 months after TTT. The amplitudes of the FMERGs were reduced in all eyes before TTT. In eyes with occult CNV, the mean b-wave amplitude increased significantly after TTT (p = 0.0260 at 3 months, p = 0.0142 at 6 months). When the change of foveal thickness was less than 20% after TTT, all eyes with occult CNV had a 30% or more increase in the b-wave amplitude. In eyes with classic CNV, the mean amplitude of the a- and b-waves did not change significantly after TTT., Conclusions: TTT improves macular function in eyes with occult CNV associated with age-related macular degeneration more when the change of foveal thickness is slight., (Copyright 2005 S. Karger AG, Basel)

Purpose: To evaluate the short- and long-term changes of focal macular electroretinograms (fmERGs) after macular translocation with 360 degrees retinotomy., Methods: This was a retrospective study. fmERGs were recorded in 19 eyes of 19 consecutive patients who underwent macular translocation with 360 degrees retinotomy for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD; 17 eyes) or polypoidal choroidal vasculopathy (2 eyes). The changes in the fmERGs, recorded before, shortly after (6-12 months; mean 8.3 months), and more than 18 months (18-30 months; mean 22.4 months) after surgery from 12 eyes, were analyzed. A 15 degrees stimulus centered on the fovea was used to elicit the fmERGs., Results: The mean logarithm of minimum angle of resolution (logMAR) was 1.06 +/- 0.07 (20/230) before surgery, 0.78 +/- 0.08 (20/121) early after surgery (n = 19), and 0.64 +/- 0.07 (20/87) late after surgery (n = 12). These improvements in visual acuity were significant (P = 0.0074, P = 0.0050, respectively). Before surgery, the amplitudes of all components of the fmERGs were markedly reduced in all eyes. The mean b-wave amplitude in 17 AMD eyes recorded early after surgery was significantly larger (P = 0.0262), and the mean a-wave amplitude was also increased but not significantly (P = 0.1180). The mean amplitudes of the a- and b-waves in 10 AMD eyes recorded after 18 months were significantly larger than those before the surgery (P = 0.0218, and P = 0.0284). The mean implicit time of the b-wave in 17 AMD eyes decreased early after surgery, and a further decrease was detected at the later testing time., Conclusions: These results indicate that macular function is partially recoverable after macular translocation in some patients.

Purpose: To determine if aniseikonia appears on the Hess [Screen] Chart and if it can be measured thereby; and to compare such measurement to the standard Awaya New Aniseikonia Test in both artificial and pathologic aniseikonia., Subjects and Methods: Twenty normal subjects with 20% artificial induced aniseikonia (Group 1) and 21 patients with pathologic aniseikonia (Group 2) were examined with the New Aniseikonia Test (NAT) and the Hess Chart. Group 2 was divided into three subgroups: Group 2-1, 13 patients with aphakia, whose operated eyes were more hypermetropic that their better eyes; Group 2-2, 3 patients with myopic anisometropia more than 5 diopters; and Group 2-3, 5 patients who had received macular translocation surgery (MTS)., Results: In normals, measurement of the 20% artificial aniseikonia ranged from 10% to 21% (mean 15%) using the NAT, and from 16% to 39% (mean 27.1% vertically and 24.6% horizontally) using the Hess Chart. In the 21 patients with pathologic aniseikonia, the NAT measurements ranged from 0% to 24% (upper limit of the NAT) and the Hess Chart measurements ranged from 0% to 65%. A large amount of the aniseikonia that appeared on the Hess Chart disappeared or was significantly reduced by changing the spectacle correction to a contact lens or intraocular lens., Conclusion: The aniseikonia that appeared on the Hess Chart was dynamic aniseikonia, due to rotational magnification inherent and unavoidable in the execution of the aniseikonia measurement on the Hess Chart. Aniseikonia, not due to refractive errors brought on by retinal surgery such as MTS, is difficult to correct with iseikonic lenses or other optical means.

Purpose: To study local retinal cone function in patients with X-linked retinoschisis (XLRS) by multifocal ERGs (mfERGs)., Methods: mfERGs were recorded from seven eyes of seven patients with XLRS (mean age +/- SD, 22.1 +/- 3.2 years; range, 18 to 25 years). Five eyes had microcystic changes in the macula and two eyes had nonspecific macular degeneration. Two eyes had peripheral retinoschisis, and some of the stimuli fell on this area. The stimulus array consisted of 103 hexagons and the total recording time was set at approximately 4 minutes. The amplitudes and implicit times of both focal and summed responses for the first- and second-order kernels were analyzed., Results: The amplitudes of the first-order kernel were markedly reduced in the central retina in all eyes. A large variation was observed in the amplitudes outside the fovea. The amplitudes of the focal cone ERGs at the peripheral retinoschisis did not differ from those recorded from adjacent retinal loci without the retinoschisis. The implicit times of the first-order kernel were significantly delayed, and the amplitudes of the second-order kernels were more affected than the first-order kernels across the whole field in all XLRS eyes., Conclusions: The cone-mediated retinal responses were more impaired in the central than peripheral retina in eyes with XLRS. Delayed implicit times of the first-order kernel and reduced second-order kernel across the whole testing field in all XLRS eyes suggest that there is widespread cone-system dysfunction in XLRS.

Purpose: To evaluate the changes in the focal macular electroretinogram (FMERG) and foveal retinal thickness after vitrectomy for diabetic macular edema (DME)., Methods: FMERGs were elicited from 25 eyes of 21 patients (ages 29-75 years) who underwent vitrectomy for DME by a 15 degrees stimulus. A posterior vitreous detachment (PVD) was created during surgery in 19 eyes (group 1), and 4 eyes had a PVD before surgery (group 2). In the remaining 2 eyes, a PVD could not be created (group 3). FMERGs were recorded before and 3, 6, and 12 months after vitrectomy. The foveal thickness, determined by optical coherence tomography (OCT), and visual acuity were measured on the same day as the FMERG recordings., Results: The postoperative visual acuity (logarithm of the minimum angle of resolution [logMAR]) improved gradually after the surgery and was significantly better at 12 months in eyes in group 1 (P = 0.0393). The postoperative mean foveal thickness was significantly less at 3 months after surgery in group 1 eyes (P = 0.0006), and there was a further decrease thereafter. In the 2 eyes in group 3, the decreased foveal thickness 3 and 6 months after surgery became thicker at 12 months. The mean b-wave amplitude of the FMERGs increased significantly at 12 months in group 1 eyes (P = 0.0297). The mean implicit time of a- and b-waves was more delayed at 3 months, and the change in a-wave was statistically significant in group 1 eyes (P = 0.0474). There was a wide range of changes in the b-wave amplitude at 12 months, however, the increase in the b-wave was correlated with the decrease in foveal thickness (r =.49, P = 0.012)., Conclusions: A disparity in the time course and degree of recovery of the foveal thickness and macular retinal function was found in eyes with DME after vitrectomy. Part of the functional recovery could be attributed to decreased retinal thickness and the absorption of the subretinal fluid.

Objective: To describe retinal and optic disc atrophy and a progressive decrease of visual function in 2 Japanese brothers. Both had a mutation in the CACNA1F gene, the causative gene of incomplete congenital stationary night blindness (CSNB)., Methods: We studied observational case reports and performed comprehensive ophthalmologic examinations including best-corrected visual acuity, biomicroscopy, ophthalmoscopy, fundus photography, and electroretinography. Genomic DNA was extracted from the peripheral blood, and all 48 exons of the CACNA1F gene were directly sequenced., Results: The 2 brothers had retinal and optic disc atrophy and a progressive reduction of visual acuity with increasing age. Although these clinical features are not typical of previous patients with incomplete CSNB, both patients had an in-frame mutation with deletion and insertion in exon 4 of the CACNA1F gene. In both patients, the bright-flash, mixed rod-cone electroretinogram had a negative configuration, a characteristic of incomplete CSNB. However, the full-field scotopic and photopic electroretinograms were nonrecordable, indicating severe, diffuse retinal malfunction, which is not typical in incomplete CSNB., Conclusion: These findings indicate that a mutation of the CACNA1F gene may be associated with retinal and optic disc atrophy with a progressive decline of visual function. Clinical Relevance In patients with retinal and optic disc atrophy associated with negative-type electroretinograms, a CACNA1F gene mutation should be considered.

Purpose: Occult macular dystrophy (OMD) is an inherited macular dystrophy characterized by a progressive macular dysfunction without any visible fundus abnormality. We studied the foveal thickness in patients with OMD using optical coherence tomography (OCT)., Design: Observational case series. Foveal thickness by OCT images., Methods: Foveal thickness obtained from 22 eyes of 11 patients with OMD was compared with that from 27 eyes of 20 age-matched normal controls., Results: Mean foveal thickness in the patients group (96.5 +/- 19.5 microm) was significantly thinner than that in the normal controls (133.3 +/- 9.0 microm, P <.0001, Mann-Whitney U test). Eighteen of 22 eyes with OMD had foveal thickness that were thinner than the lower limit of the normal range. There was no statistically significant correlation between the foveal thickness and visual acuity, age, or duration from onset., Conclusion: These results demonstrated that there are significant anatomic changes in the macula of patients with OMD.

Purpose: To study the function and morphology of the macula of the eye before and after the removal of unilateral idiopathic epiretinal membrane (ERM)., Methods: Focal macular electroretinograms (fmERGs) elicited by a 15 degrees stimulus were recorded in 37 eyes of 37 patients with a unilateral ERM. The amplitudes of the a- and b-waves and the oscillatory potentials (OPs) were compared with the corresponding waves in the normal fellow eyes before and after removal of the ERM. In 29 eyes followed up for more than 6 months after surgery, the fmERGs and foveal and parafoveal thicknesses, measured by optical coherence tomography (OCT), were evaluated., Results: Before surgery, the mean amplitudes of all components of the fmERGs were significantly smaller than in the fellow eyes, with the decrease largest for the OPs, followed by the b-waves and then the a-waves. The eyes with less severely reduced a-wave amplitude (>70% of the fellow eyes) had significantly lower b-wave to a-wave (b/a) ratios. After surgery, the amplitudes of the b-wave and OPs were still significantly smaller in the affected eyes. The mean foveal and parafoveal thicknesses were significantly less after surgery; however, the thickness was still more in the affected eyes. The decrease of the OPs remained after surgery and correlated with increased parafoveal thickness (r = -0.460, P = 0.011)., Conclusions: The decreased fmERGs indicate that macular function is impaired in eyes with ERM. The decrease of the b-wave and OPs in the 29 eyes examined after vitrectomy may be due to the still thickened macular retina.

Purpose: To report a case of enhanced S-cone syndrome associated with subfoveal neovascularization., Design: Observational case report., Methods: A 23-year-old man, who was first examined at age 9 years, was found to have enhanced S-cone syndrome by clinical, electrophysiological, and molecular genetic examinations., Results: At 9 years of age, a subfoveal neovascularization was present in his right eye and corrected visual acuity was RE: 0.15 and LE: 1.0. After he was 20 years old, cystoid changes in the macula of the left eye appeared and visual acuity, in the left eye, decreased from 1.0 to 0.02., Conclusion: The clinical course of enhanced S-cone syndrome is progressive, and we suggest that the subretinal neovascularization is a phenotypic variation of enhanced S-cone syndrome.

Purpose: One of the methods used in macular translocation (MT) surgery for subfoveal neovascularization is to create a temporary total retinal detachment followed by a 360 degrees retinotomy. The whole retina is then shifted from the original surface of the retinal pigment epithelium (RPE), resulting in an unusual retina and RPE complex. The purpose of this study was to assess retinal function after MT surgery., Methods: Full-field electroretinograms (ERGs) were recorded before and 4 to 8 months (mean, 5.4 months) after MT surgery with a 360 degrees retinotomy in 15 consecutive patients with age-related macular degeneration (10 eyes), high myopia (4 eyes), and polypoidal choroidal vasculopathy (1 eye). Their ages ranged from 57 to 74 years. The angle of rotation of the retina ranged from 18 degrees to 45 degrees (mean +/- SE, 30 +/- 2 degrees). In addition to the recording of the standard rod and mixed rod-cone ERGs after 30 minutes of dark adaptation, the cone single flash and 30-Hz flicker ERGs were recorded immediately after a light-adapting background was turned on (LA(0)) and also after 10 minutes of light adaptation (LA(10))., Results: The mean amplitude of the full-field ERGs was reduced after surgery by 44% for the rod response, by 24% for the mixed rod-cone b-wave, by 12% and 35% for the cone single-flash b-wave at LA(0) and 30-Hz flicker ERGs at LA(0), respectively. The mean implicit times were delayed by 8 msec for the rod response, by 2 msec for the mixed rod-cone oscillatory potential (OP1), by 4 msec for the cone single-flash b-wave at LA(0), and by 6 msec for the 30-Hz flicker at LA(0)., Conclusions: These results demonstrated a functional alteration in both the rod and cone components of the ERGs for the entire retina after MT surgery.

Purpose: The removal of the internal limiting membrane (ILM) for traction maculopathy has recently been advocated. However, it is generally believed that the ILM plays an important role in retinal function, because it is the basal lamina of the Müller cells that are involved in the generation of the electroretinogram (ERG) b-wave. To date, there has been no objective assessment of retinal function on removing the ILM. In this study, the changes of each component of the focal macular electroretinograms (FMERGs) were investigated in eyes before and after the ILM was removed in the macular area during surgery for idiopathic macular holes (IMHs)., Methods: FMERGs were elicited by a 15 degrees stimulus centered on the fovea and monitored by an infrared fundus camera. FMERGs were recorded from 49 eyes of 48 patients with IMHs before and 6 weeks after anatomically successful macular hole surgery. Whether an eye had or did not have the ILM removed was randomly determined. The ILM was removed in 30 eyes (ILM-off group) and was not removed in 19 eyes (ILM-on group). Six months after surgery, the same examination was performed in 27 eyes of the ILM-off group and in 15 eyes of the ILM-on group. The amplitudes and implicit times of the a- and b-waves and the mean amplitudes and implicit times of the first three oscillatory potentials (OP1 to OP3) were compared before and after surgery within and between the groups., Results: Visual acuity increased significantly after surgery in both groups. In the ILM-on group, the amplitude of the a- and b-waves and the OPs increased significantly 6 months after surgery (P: = 0.0093, P: = 0.0019, P: = 0.0024, respectively, paired t-test). In the ILM-off group, the a-wave amplitude and mean OP amplitudes were significantly larger 6 months after surgery (P: = 0.0077, P: = 0.0030, respectively, paired t-test). The b-wave amplitude, however, did not change significantly. The percentage increase in the b-wave amplitude 6 months after surgery was significantly higher in the ILM-on group (44.0%) than in the ILM-off group (15.0%; P: = 0.037, t-test)., Conclusions: The removal of the ILM had no adverse effect on visual acuity. However, the selective delay of recovery of the FMERG b-wave 6 months after surgery suggests an alteration of retinal physiology in the macular region.

We determined the clinical usefulness of a new contact lens electrode with built-in, white light-emitting diodes (LEDs) for full-field electroretinograms (ERGs). Three, high-brightness white LEDs were incorporated into a contact lens electrode and served as the source for the stimulus and the background. The stimulus intensity, stimulus duration and background illumination were regulated by a small LED control device. Maximum stimulus and background intensities were 3.9 and 3.6 log cd/m2, respectively. We successfully recorded intensity-response series for scotopic and photopic ERGs. We also recorded a duration-series for photopic ERGs, and ERGs that were comparable to the ISCEV standardized ERGs. The compactness and ease of using this system suggest that it will be clinically useful under different conditions.

Purpose: Occult macular dystrophy (OMD) is an unusual macular dystrophy presenting with an essentially normal fundus and fluorescein angiography but with progressive central visual loss. The authors studied the function of local retinal areas in the posterior pole of patients with OMD using multifocal electroretinograms (ERGs)., Methods: Multifocal ERGs were recorded using the Visual Evoked Response Imaging System with 61 hexagonal elements within a visual field of 30 degrees radius from 8 OMD patients and 20 age-matched, normal subjects. The amplitudes and implicit times of the patients and normal control subjects were compared at the various retinal eccentricities. RESULTs. The amplitudes of the multifocal ERGs in the OMD patients were markedly reduced in the central 7 degrees of the fovea. The difference of the ERG amplitudes between OMD and normal subjects became smaller toward the peripheral retina. Most OMD patients had slight but significantly delayed implicit times across the whole testing field, and the differences between the OMD and the normal subjects did not change with retinal eccentricity., Conclusions: Our results for multifocal ERG amplitudes support the idea that OMD patients have localized retinal dysfunction distal to the ganglion cells in the central retina. The delayed implicit times across the whole test field suggest that the retinal dysfunction has a broader boundary than expected by ERG amplitudes and psychophysical perimetric results.

Purpose: The b-wave of the human photopic electroretinogram (ERG) elicited by a short-flash increases in amplitude with increasing stimulus intensities at lower stimulus levels, but then decreases at higher stimulus intensities. The purpose of the present study was to explore this phenomenon in more detail, using short- and long-flash stimuli., Methods: The intensity-response functions of the b-wave elicited by short- and long-flashes were compared from threshold to higher stimulus intensities in 5 normal subjects. Short- and long-flash ERGs were elicited under rod-saturating background levels using white light-emitting diodes built into a contact lens electrode., Results: Whereas the amplitude of the short-flash b-wave decreased at higher intensities, the amplitude of the long-flash ERG b-wave did not decrease but plateaued. The long-flash ERG d-wave or OFF-response decreased at higher stimulus levels as did the short-flash elicited b-wave., Conclusions: Because it is widely accepted that the b-wave and the OFF-response d-wave interact to produce a single positive response, our results suggest that the decrease in the b-wave amplitude at high stimulus intensity is caused by the decrease of the d-wave at the higher stimulus intensities.

Purpose: To determine using the multifocal ERG technique whether there are any regional differences in the increase in the amplitude of cone electroretinograms (ERGs) during light adaptation., Methods: Multifocal ERGs were recorded with the Visual Evoked Response Imaging System from five normal subjects. Thirty-seven hexagonal stimulus elements and a recording time of 60 seconds were used. After 20 minutes of dark adaptation, multifocal ERGs were repeatedly recorded every 2 minutes over a period of 16 minutes. The amplitudes of the multifocal ERGs at different eccentricities were compared during the 16 minutes of light adaptation., Results: During the 16 minutes of light adaptation, the summed responses of the multifocal ERGs increased in amplitude an average of 36% and 47% for the negative and positive components, respectively. The magnitude of increase was minimal in the central retina at 22% and was significantly larger in the peripheral retina at 58%. The implicit time was slightly increased (<4%) with light adaptation, but there were no regional differences., Conclusions: The results demonstrated that there are topographic variations in the amplitude increase of cone ERGs during light adaptation. This topographic variation indicates that the mechanism for the increase must be based on known regional differences in the retina.