島田 佳明

We report a case of Fabry disease diagnosed after recurrent cerebral infarction in a patient with central retinal artery occlusion (CRAO). A 23-year-old man presented with vision loss in his right eye (20/2000), showing CRAO. There was no identified cause for the loss of vision; however, corneal verticillata was detected in both eyes on the recurrence of the cerebral infarction. The α-galactosidase activity in leukocytes was significantly reduced to <0.3 nmol/mg of protein/hour, leading to a definitive diagnosis of Fabry disease. Enzyme replacement therapy was commenced concomitant to rehabilitation. It is necessary to identify Fabry disease as a cause of CRAO in young individuals, and the detection of cornea verticillata, used frequently as an ocular finding, is helpful.

PURPOSE: We report a case of neuroretinitis associated with cat scratch disease (CSD) in young children. METHOD: Case report. RESULTS: A 16-month-old boy was admitted for a detailed examination and treatment of a fever of unknown origin. Blood tests revealed no significant findings other than a white blood cell count of 16,100/mm3 and C-reactive protein level of 9.89 mg/dL. Computed tomography revealed no relevant findings to determine the causative disease. Antibiotic therapy with cefotaxime was initiated; however, the fever did not resolve. The patient was referred to our department for further examination to detect the cause of the fever. Fundoscopy revealed neuroretinitis in the right eye. His mother reported a history of breeding cats. Cat scratch disease (CSD) was suspected based on the clinical course and fundus findings. Cefotaxime was discontinued, and azithromycin, rifampicin, and prednisolone were administered, following which the fever disappeared and fundus findings improved. Immunoglobulin G (IgG) and IgM antibodies against Bartonella henselae was positive, leading to a definitive diagnosis of CSD. CONCLUSION: Infants cannot complain of decreased visual acuity; therefore, these findings may be overlooked unless a fundus examination is performed. As in this case, the early detection of neuroretinitis by an ophthalmologist may help in the diagnosis of CSD. It is extremely difficult to capture a photograph of the fundus of an infant, and recording with a smartphone is relatively simple and useful for monitoring continuous changes. Summary. We describe a case of neuroretinitis associated with cat scratch disease (CSD) that was diagnosed on the basis of fundus findings. The findings suggest the importance of an aggressive ophthalmologic examination when CSD is suspected in young children who are unable to describe their symptoms.

Background: The acute physiological changes induced by focal retinal photocoagulation (PC) have been largely unexplored. Methods: This was a case-series study. We recorded multifocal electroretinograms (mfERGs) just before PC, and mfERGs were also recorded 5′, 15′, one hour, 24 h, and one week after the PCs. Transient changes of mfERGs were analyzed in eyes which underwent PCs to treat diabetic macular edema. The mfERGs recorded from the predominantly irradiated area and that from non-irradiated areas were analyzed separately. Results: Fifteen eyes of 15 patients were included in this study. The mfERGs elicited from non-irradiated areas did not change after PC, but the mfERGs elicited from the irradiated area changed with time; the amplitude was larger at 60′ than that before (p &lt; 0.05) and at 5′ after PC (p &lt; 0.01) and significantly smaller at 24 h and 1 week than that before and at 60′ after the PC (p &lt; 0.01). The implicit time was significantly prolonged after PC. mfERG on irradiated area with the severe diabetic change was less altered after PCs. Conclusions: The transient increase in the amplitude at 60′ likely resulted from a biological amplification of partially damaged cells adjacent to the PC spots. The mfERGs manifested the dynamic alterations of the retinal function following PCs.

OBJECTIVES: We compared the effects of sub-Tenon's capsule anesthesia (STA) and trans-Tenon's capsule retrobulbar anesthesia (TTRBA) in 68 patients with epiretinal membrane. METHODS: Either STA or TTRBA was induced with 3 mL of lidocaine (2%) before vitrectomy combined with phacoemulsification and aspiration (phacovitrectomy). Akinesia was evaluated by range of eye movement (ROEM) in upward, downward, nasal, and temporal directions at 4, 10, and 30 minutes after injection. Analgesia was evaluated with a visual analogue pain score, which ranged from 0 to 10. RESULTS: The mean cumulative ROEMs were 1.44±1.02 corneal diameters (CDs) at 4 minutes, 0.55±0.76 CDs at 10 minutes, and 0.26±0.33 CDs at 30 minutes in patients who received STA; these values were 0.39±0.35 CDs at 4 minutes, 0.22±0.30 CDs at 10 minutes, and 0.13±0.29 CDs at 30 minutes in patients who received TTRBA. At both 4 and 10 minutes, the cumulative ROEMs in all directions, as well as the temporal ROEMs, were significantly larger in patients who received STA than in patients who received TTRBA. Pain scores did not significantly differ between groups at any time point. CONCLUSIONS: STA and TTRBA produced identical degrees of analgesia, but akinesia was slower in patients who received STA. TTRBA might be preferable for patients undergoing brief vitrectomy.

OBJECTIVES: The aim of this study was to determine whether age correlates with amplitude and latency, when full-field electroretinography (ERG) is performed using skin electrodes. The ability of pulse reference power line noise reduction (PURE) to dampen the noise associated with the use of skin electrodes, was also investigated. METHODS: ERG was performed on 77 eyes in 77 healthy subjects (mean age: 55.6±19.0 years; age range: 9 to 86 years). Subjects with -5D or higher myopia, Emery-Little grade III or higher cataracts, retinal disease, uveitis, glaucoma, ≤5 mm mydriasis, or a history of intraocular surgery other than cataract surgery, were excluded. The active, reference, and ground electrodes were placed on the lower eyelid, outer canthus, and earlobe, respectively. Responses were averaged 10 times for dark-adapted (DA) ERGs, and 32 to 64 times for light-adapted (LA) ERGs. Noise was removed using the PURE method. RESULTS: The DA ERGs without PURE were so noisy that the amplitude or latency could not be determined, whereas those with PURE were comparatively quieter. ERG with PURE demonstrated a significant negative correlation between age and amplitude and a significant positive correlation between age and latency. CONCLUSIONS: We could record the measurable ERG waveforms with skin electrodes by using the PURE method, especially in fewer averaged conditions. It is suggested that skin electrode with PURE is suitable to examine the pathological ERGs, and other types of electrodes. It is recommended that the aging effect should be taken into consideration when pathological ERGs are evaluated.

目的:新しく開発したアークスキャン式広画角超音波診断装置を用いて、健常眼の眼軸と赤道部径を計測して眼球の形状を検討した。対象および方法:対象は正常眼41眼。B-mode画像より、眼軸長axial length(AL)、赤道部水平径horizontal diameter(HD)、赤道部垂直径vertical diameter(VD)を定量した。結果:全体でALとHD、VDは正の相関を認めた。長眼軸群と非長眼軸群に分けて検討すると長眼軸群でAL、VD、HDが有意に大きかった。赤道部径/眼軸長は非長眼軸群が有意に大きかった。角膜屈折力平均値とHD、VDは負の相関を認めた。結論:広画角超音波診断装置は眼球赤道部径を測定することができ、眼軸延長に伴う眼球形態の変化を3次元的にとらえることができた。この装置は眼球形態を測定するデバイスとして臨床上有用と考えられた。(著者抄録)

肥厚性硬膜炎は脳脊髄の硬膜に炎症性肥厚を生じ、硬膜を貫通する脳神経や脊髄神経根を圧迫することで痛み、麻痺、失明や難聴、また誤嚥性肺炎などをもたらしうる疾患である。感染や腫瘍など明らかな原因があるものと、ANCA関連疾患やIgG4関連疾患といった免疫機序が関わる場合があり、後者では他臓器の肉芽腫や線維化が生じ、発病の発端が眼科や耳鼻科領域ないしは腎臓などの全身臓器のことがある。原因が特定できないものも多く存在する。診断に造影MRIは必須で、続発性の鑑別のためには治療前に各種自己抗体、抗ANCA抗体、IgG4、β-D-グルカンの測定や細菌学的な検索、副鼻腔や硬膜の可能な限りの生検が必要である。真菌感染では糖尿病を合併することが多く、治療は抗真菌薬を先行させステロイドも使用する。非感染性のものは上記膠原病近縁ないしは免疫介在性と考えられ、種々の免疫修飾療法が試みられ、ステロイド、IVIg、タクロリムス、リツキシマブ、サイクロフォスファマイドなどの使用が報告されている。ステロイド漸減中に再発がみられることが多く、病態別の治療指針の確立が待たれる。(著者抄録)

The current case involved a 59-year-old woman who was referred to our hospital with bilateral optic nerve abnormality and gradually progressive bilateral inferior visual field defects. An ophthalmological examination revealed superficial optic nerve head drusen (ONHD) and bilateral inferior altitudinal hemianopsia, but no intracranial lesions. The results of an angiogram revealed no evidence of retinal vascular occlusion or anterior ischaemic optic neuropathy (AION). Prior reports suggested that drusen-induced hemianopsia was slowly progressive but that ONHD-induced AION caused acute altitudinal hemianopsia, which led us to the diagnosis of bilateral drusen-induced altitudinal hemianopsia.

Purpose: To determine the compliance with the face-down positioning (FDP) of the patients who had undergone vitrectomy and gas tamponade. Methods: One hundred and twenty-seven patients, 45 females and 82 males, who had undergone primary vitrectomy and gas tamponade for rhegmatogenous retinal detachments were studied. The FDP score was determined as 4 per day for 3 days after the surgery. The patient was given a score of one if the nurse found that the patient was in the FDP and zero if not in the FDP. A perfect FDP score was 12. Results: The mean ± SD FDP score was 10.2 ± 1.8 with a range of 3 to 12. Females (10.7 ± 1.2) scored significantly higher than males (9.9 ± 2.1) (Mann-Whitney U test: P , 0.05). Patients who scored a perfect 12 were 38 (29.9% female, 14:31.1% male 24:29.3%). Low scorers ,8 were all males (12:14.6%) and no females (0:0.0%). Age did not seem to be related. Only 1 patient failed to achieve retinal attachment, although she had scored a perfect 12. Conclusion: The compliance was considerably varied among patients. Some patients failed nearly or more than half times, and they were mostly males. The significance of the FDP to treat rhegmatogenous retinal detachment needs to be examined in a further investigation.

BACKGROUND AND OBJECTIVE: The authors developed a new technique for retrobulbar anesthesia and compared it with the conventional transcuta-neous method in 223 eyes undergoing vitrectomy. PATIENTS AND METHODS: In the new technique, a 24-mm-long 19-gauge curved cannula with a 27-gauge straight needle with an oval tip was inserted into the sub-Tenon's space, and then the oval-tipped needle was replaced with a 50-mm-long 25-gauge curved needle. Anesthetic was then injected into the muscle cone from the syringe. The authors compared 118 eyes undergoing vitrectomy with the new technique and 105 eyes undergoing the procedure with conventional anesthesia. RESULTS: The pain scores were 0.1 ± 0.32 for the new technique and 1.57 ± 0.73 for the conventional technique (P &lt .001). Additional anesthetic required was 0.1 ± 0.33 mL using the new technique and 0.3 ± 0.68 mL using the conventional method (P = .03). CONCLUSION: This novel approach to retrobulbar anesthesia using a guarded cannula is safe and effective, causing less pain than the conventional technique.

Purpose: The aim was to evaluate the value of multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) in predicting post-operative visual acuity (post-VA) after removal of an idiopathic epiretinal membrane (ERM). Methods: Fifty-one eyes of 51 patients with an idiopathic macular ERM were examined by OCT and mfERG before three-port pars plana vitrectomy with removal of the ERM. The parameters of the OCT images and mfERGs, pre-operative visual acuity (pre-VA) and the duration of symptoms (DS) were compared with the post-VA. Results: The pre-VA (r = 0.570, p &lt; 0.001) and the duration of the symptoms (r = 0.389, p &lt; 0.035; n = 35) were significantly correlated with the post-VA. The central retinal thickness (CRT) was significantly correlated with the pre-VA (r = 0.379, p &lt; 0.01) and the post-VA (r = 0.318, p &lt; 0.03). The amplitudes of macular electroretinogram (amERGs) were not significantly correlated with the pre-VA or post-VA. The CRT to amERG ratio (CRT/amERG) was correlated with the post-VA (r = 0.429, p &lt; 0.002) but not with the pre-VA (p &gt; 0.1). Comparative analyses among groups of cases based on CRT/amERG showed significant differences in the post-VA but not in the pre-VA and the duration of symptoms. Conclusion: As with the large CRT/amERG, the pre-operative morphologically thickened and electroretinographically reduced retinas have a greater likelihood of being affected by the irreversible photoreceptor damages that could have been masked or modified by other factors before the removal of the ERM. Because the CRT/amERG values are obtained objectively, they should be valuable in predicting the post-operative visual function along with the pre-VA and the duration of symptoms.

PURPOSE. To investigate the functional characteristics of the detached retina on a serous retinal detachment (SRD) in eyes with central serous chorioretinopathy (CSC) with spared visual acuity. METHODS. Multifocal electroretinograms (mfERGs) were recorded with a long recording time of 14 minutes, 34 seconds, to obtain accurate measurement of the second-order kernel (K2.1), an index of functional adaptability of the retina, from seven eyes with CSC (visual acuity, &gt;= 1.0). The first-order kernel (K1) and the K2.1, elicited by stimulating the area of the SRD, were compared with those from the corresponding areas in eyes of 15 age-matched volunteers (controls) and in 6 eyes of patients with diabetic retinopathy (DR) that have been reported to have a K2.1 attenuation. RESULTS. K2.1 was essentially flat in the SRD eye. The K2.1 amplitude and log-scaled amplitude ratio of K2.1 to K1 (K2.1/K1) were severely reduced (to &lt;95% confidence interval [CI] of control levels) in all eyes. The value of K2.1/K1 of the SRD was less than that in any of the control and DR eyes. K1 was moderately reduced but was not smaller than the 95% CI of control eyes. The mfERGs from the area without the SRD and those from the fellow eyes did not differ significantly from those in control eyes. CONCLUSIONS. A possible cause of the flat K2.1 observed on the SRD is the separation of the sensory retina. A substantial disparity between the recovery of cones and rods could contribute to the loss of retinal adaptability, resulting in the flat K2.1 as well as the unique visual impairments in CSC eyes. (Invest Ophthalmol Vis Sci. 2010; 51: 3210-3215) DOI:10.1167/iovs.09-4637

Purpose: To evaluate the effect of photodynamic therapy (PDT) on retinal functions, such as oxygen saturation, blood flow, and electrophysiological function using Fourier transform-based spectral retinal imaging (SRI), Heidelberg retinal flowmeter (HRF), and multifocal electroretinogram (mfERG). Methods: This was a prospective interventional case series. Twenty-two patients with age-related macular degeneration (AMD) with unilateral choroidal neovascularization (CNV) were examined using SRI, HRF, and mfERG before and 1 week and 1 month after PDT. Eleven fellow eyes without CNV and 11 control eyes of 11 age-matched healthy volunteers were also investigated. Eleven of 22 patients with neovascular AMD were retreated using verteporfin PDT and examined using a protocol similar to the one used for the first treatment. Results: Oxygen saturation levels in the macula of eyes with neovascular AMD were significantly higher than those in normal control eyes (P = 0.026) but were not significantly higher in eyes with nonneovascular AMD. Oxygen saturation levels decreased 1 week after a single treatment (P = 4.59 × 10) and retreatment (P = 0.0134) and recovered to baseline levels at 1 month follow-up (P &gt 0.05). HRF demonstrated reduced mean blood flow at 1 week after single treatment (P = 9.22 × 10) and retreatment (P = 0.0307). One month after PDT, mean blood flow tended to show recovery. There was a similar decrease in mfERG amplitude 1 week after treatment, but the logarithm of minimum angular resolution (logMAR) vision was stable or improved throughout follow-up. Conclusion: Oxygen saturation levels, mean blood flow, and mfERG amplitude decreased 1 week after PDT treatment in both single treatment and retreatment groups. Although logMAR vision is stable or improved, our data showed transient functional deterioration in the retina after PDT treatment. © The Ophthalmic Communications Society, Inc.

To report three cases of idiopathic Creutzfeldt-Jakob disease (CJD) with visual symptoms. Patient 1 initially visited our ophthalmology department complaining of blurred vision. Electro-retinography (ERG) showed a selective reduction of the b wave before she was diagnosed with CJD. Patient 2 had normal ERG results even with severely advanced CJD. However, a reduction of the b wave on ERG was observed 1 month before the patient died. Patient 3 had visual disturbances at the initial visit, but the ERG result was normal even after the CJD had advanced. Atrophy of the visual cortex was later observed. CJD can alter the vision in various ways. The selective reduction of the b wave on ERG indicates the retinal involvement. However, visual disturbances may occur without the retinal implications. Ophthalmologists should be aware that the visual impairment can be the first symptom of CJD.

A 51-year-old man had reduced vision and bilateral optic disc swelling as the initial clinical manifestation of multiple myeloma. Brain imaging failed to disclose any abnormalities. Before any therapy was begun, visual function began to improve substantially. Three months after chemotherapy was started, visual function and optic disc appearance returned to near normal. There were no features to suggest polyneuropathy-organomegaly-endocrinopathy-M protein-skin changes (POEMS) syndrome. Visual loss in myeloma is usually caused by compression or infiltration of the optic nerves by tumor. The mechanism of the optic neuropathy in this case remains unknown. © 2006 Lippincott Williams &amp Wilkins, Inc.

Objective: To determine retinal function after transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularization using multifocal electroretinograms (mfERGs). Methods: Multifocal electroretinograms were recorded before and after TTT (wavelength, 810 nm diameter, 3 mm duration, 60 seconds power, 350 mW) in 9 eyes in 9 patients with subfoveal choroidal neovascularizations. The stimulus consisted of 7 hexagons the central hexagon covered the laser-irradiated area and the surrounding 6 hexagons covered the nonirradiated area. Each recording was completed within 1 minute, and mfERGs were recorded periodically during the first 60 minutes after TTT and also at 24 hours and 1 week after TTT. Results: The amplitude of mfERGs from irradiated areas was significantly reduced at 1 minute after TTT (P&lt .01) and then recovered soon. The peak time was prolonged at 15 minutes after TTT (P&lt .01), recovered to pre-TTT levels at 60 minutes, and then was prolonged again at 24 hours (P&lt .05) and 1 week (P&lt .05) after TTT. The mfERGs in nonirradiated areas were unchanged during the observational period. Conclusions: We found amplitude reduction in central focal ERGs at 1 minute after TTT, transient peak-time delay at 15 minutes, and a delay at 24 hours. Early reduction is probably directly caused by an increase in temperature during TTT as previously reported in focal flicker ERGs. Peak-time delays at 15 minutes and 24 hours may be caused by other factors, such as increased intracellular calcium (Ca 2+), the release of nitric oxide or heat shock proteins, vasodilation, or change in choroidal neovascularization. Our findings indicate that recording mfERGs may be a useful tool for evaluating TTT procedures. ©2005 American Medical Association. All rights reserved.

The multifocal VEPs (mfVEPs) obtained from the right and left eyes are practically identical in shape and amplitude, however small differences in the implicit times (ITs) have been reported. We have analyzed the ITs in detail to show that they are dependent on the radial location of the stimulus in the visual field. The differences are large, up to 8.3 ms, near the horizontal meridian, and are probably due to differences in the distances of the nasal and temporal ganglion cell axons from the optic disc. The intraretinal conduction velocity of ganglion cell axons, determined by dividing the axonal length to the optic disc by the ITs, was 0.29 m/s at an eccentricity of 0.5-1.4degrees and 1.39 m/s at 8-12degrees. (C) 2004 Elsevier Ltd. All rights reserved.

Purpose: To investigate the retinal responses generated by flash interactions in a recently introduced "global (full-screen) flash" stimulus paradigm to record the multifocal electroretinogram (mfERG). Methods: Five normal individuals were studied with stimulation combining multifocal (pseudorandom) flashes with interleaved global (periodic, full-screen) flashes. The intensities of the two flashes were independently varied. Two distinct first-order response components were obtained: the mean response to the focal flashes (referred to as the direct response, DR) and the effect of the focal flash on the responses evoked by the global flash (the induced component, IC). Results: Increasing the global flash luminance reduced DR amplitude and shortened DR implicit time. IC amplitude peaked with a moderate global flash (1.33-2.67 cds/m2). With a global flash of the right intensity, a weak focal flash could evoke a considerable IC even when the DR was barely detectable. Moderate global flashes maximized the IC, and its intersubject variability was reduced at lower focal flash luminances. IC topography had a large naso-temporal asymmetry. Conclusions: While the DR is the average response generated by the local flashes regardless of the context of preceding and following flashes, the IC represents the difference in the global flash response in the presence and absence of the preceding focal flash. As the focal flashes were always preceded by the periodically occurring global flashes, the DR reflects the resulting adapted or desensitized state of the retinal patch. The pure, nonlinear IC is thought to reflect predominantly inner retinal function.

We describe a technique for removing lens fragments dropped into the vitreous cavity during cataract surgery using an optical fiber-free intravitreal surgery system (OFFISS) that was developed for bimanual vitrectomy. The dropped nucleus was removed by 2-port corneal vitrectomy using the OFFISS in 3 patients during complicated cataract surgery. No complications occurred, and good visual recovery was achieved. The OFFISS provided a good view of the fundus without fiber optics and allowed the use of 2 ports for vitrectomy through the corneal wound. This technique is suitable for cataract surgeons who have not been trained in 3-port pars plana vitrectomy.

PURPOSE. To study multifocal electroretinograms (mfERG) in patients with early-stage central alveolar choroidal dystrophy (CACD) with well-demarcated atrophic areas. METHODS. Eight eyes of eight patients with CACD (ages, 47-67 years) and 20 normal control subjects were examined. The first- and second-order kernels (K1 and K2) were extracted from the responses elicited by 61 standard hexagonal elements of a visual response imaging system. The amplitudes and peak times of the focal responses at various retinal eccentricities were studied. RESULTS. The amplitudes of K1 were reduced in the visibly atrophic areas, and they were also decreased in areas with no visible atrophy. The peak time was slightly delayed in many loci, but the delay was not as long as that in congenital stationary night blindness or diabetic retinopathy. The amplitude of K2 was very small in the central and peripheral areas, but the K2/K1 ratio in both areas was not significantly reduced, compared with that in normal subjects. CONCLUSIONS. Although the atrophic area was ophthalmoscopically well demarcated in patients with CACD, the abnormality of retinal function extended beyond the borders of the ophthalmoscopic and angiographic lesions. The retinal dysfunction outside the atrophic areas suggests a centrifugal progression of the disease, and abnormal K2 and K1 with preserved K2/K1 ratio are consistent with a presynaptic mechanism for the retinal dysfunction in this disease.

PURPOSE. To evaluate the characteristics of stray light-induced response in multifocal ERG (mfERG) elicited by the stimulus falling on the disc. METHODS. A patient with an enlarged optic disc (4 X 4 disc diameters of disc of normal fellow eye) and four normal volunteers served as subjects. The mfERGs elicited by different stimulus intensities (0.67- 4.67 cd-sec/m(2)) were recorded from the patient, and the mfERGs obtained with stimuli on the enlarged optic disc. For comparison, full-field pseudorandom ERGS (ffprERGs) were also recorded in all subjects. The first-order kernels (K1) and the second-order kernels (K2.1) were analyzed. RESULTS. A small and delayed K1 was recorded on the enlarged disc, but K2.1 was flat on the disc at all intensities. The implicit time of K1 at lower intensities was longer than at higher intensities. ffprERGs at very low intensities in the patient and normal subjects were similar to the mfERG on the disc (delayed K1 associated with flat K2. 1). CONCLUSIONS. The responses elicited by stimulating the disc were delayed in K1 and flat in K2.1. Because similar ffprERGs were observed at very low intensities, it is likely that an optic disc with high reflectance scattered the stimulus light to create a weak full-field stimulus. Thus, care must be taken when focal lesions are investigated with mfERGs.

A transparent irrigation cannula was developed to facilitate bimanual removal of subincisional lens cortex after phacoemulsification. The cannula allows visualization of the proximal cortex and provides ample inflow to maintain an inflated anterior chamber even at a high aspiration pressure. © 2002 ASCRS and ESCRS.

Objectives: To describe a new system for fiberopticfree bimanual vitrectomy and to present the outcome of 37 eyes with preretinal membranes due to diabetic retinopathy or proliferative vitreoretinopathy that underwent surgery using this system. Methods: The system consists of a 40-diopter aspheric field lens suspended from the operating microscope and a prismatic inverting device. The aspheric lens is placed above the cornea, and the illumination from the operating microscope creates an inverted image of the fundus, which is made erect by an inverter system. No fiberoptics are required, and both hands are free to use 2 microinstruments. Main Outcome Measures: The practical utility of this system and its surgical results and complications. Results: The system was used successfully in all cases. Membrane dissection and hemostasis were performed without incident. An improvement in visual acuity of 2 or more lines was found in 30 of 37 eyes. Five eyes did not reveal change of 2 or more lines, and 2 eyes had a decrease in visual acuity of more than 2 lines. There was no evidence of phototoxicity. Conclusion: This system is very useful for bimanual vitrectomy.

Aims - To assess early functional retinal changes in diabetics without retinopathy, a new multifocal stimulus paradigm was used that emphasises fast adaptive response contributions. Methods - 25 normal control subjects (25 eyes) and 11 diabetics without retinopathy (22 eyes) served as subjects. Stimulation and analysis were performed with Veris Science 4.0. A stimulation protocol was used that combines regular multifocal flicker stimulation with a periodic "global" flash inserted between the multifocal stimuli. The multifocal stimuli were presented four video frames apart. The global flash covered the entire screen in the third frame of the four frame interval. The remaining two frames were dark. The periodic global flashes could only contribute to the focal responses if they were affected by the multifocal stimulation. A non-linear component induced by the interaction of the focal and global flashes was observed. The differences between control subjects and diabetics were assessed in both the multifocal responses and their induced effect on the following global flashes. Results - The responses to focal flashes were reduced significantly in diabetics matched in age to the control subjects. The induced components showed large intersubject variability in controls and patients, and did not differ significantly between the two groups. Conclusion - The periodic global flashes produce a greater multifocal response reduction in diabetics than in normals, indicating impairment in the rate or magnitude of recovery from the bright preceding stimulus. The new stimulation protocol reveals early changes in retinal function of diabetics.

PURPOSE. To evaluate the usefulness of a new multiple-letter visual acuity chart (MLAC) for the measurement of visual acuity in patients with macular hole. METHODS. Visual acuity was measured using a standard visual acuity chart (Landolt rings, also referred to as C's) and with the MLAC in normal subjects and in patients with a cataract or a macular hole. The MLAC has 14 plates (45 × 45 cm), and on one plate, many Landolt C's were printed with the gaps pointing in the same direction and all of one size. The sizes of the letters and gaps were made to give equivalent visual acuities of 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.5, and 2.0. The spacing between the letters was 33.3% of the diameter of the C's. Each chart projected many C's onto the macular area (5° × 5°), which permitted the measurement of visual acuity at an extrafoveal point without the patient having to search for the extrafoveal point with the best acuity. RESULTS. There was no difference in the acuity measurement determined with the standard chart and the MLAC in normal subjects and patients with cataracts. Twelve of 16 patients with open macular hole, however, demonstrated higher acuity measurement (more than two lines) on the MLAC than on the standard chart. The improvement of visual acuity measurement after successful macular hole surgery was significantly less with the MLAC than with the standard chart. CONCLUSIONS. Our results suggest that the standard acuity chart, when administered before surgery, underestimates the patient's potential visual acuity after surgery, whereas the MLAC provides a better estimate of the patient's postoperative acuity. The MLAC can be a useful tool for measuring visual acuity in patients with macular hole.

We developed a new visual stimulating system for recording visual evoked cortical potentials and electroretinograms. The stimulus was a color checkerboard, in which each check kept its chromaticity but changed its luminance with its corresponding check. Color-coded pattern stimuli using red and green checks did not produce visual evoked cortical potentials, while yellow checks produced clear responses in a normal subject. Moreover, five color stairs from red and green to yellow showed only that the more colors are different, the smaller the visual evoked cortical potentials become. In addition electroretinogram recordings indicated that color-coded patterns behave in the same way as in visual evoked cortical potentials. The mechanism that causes the small color visual evoked cortical potentials may already be present in the retina. Color perception may be able to induce a suppression of responses for luminance contrast that appears to be formed already in the retina. Retinal responses were affected whether the stimulus field was color coded or not. Pattern electroretinograms appear to be more than the sum of local on and off responses.