[Three cases of retinal arterial macroaneurysm on the optic disc].

BACKGROUND: Retinal arterial macroaneurysm typically involves the second order arterioles and is relatively uncommon on the optic disc. Here, we present three cases of retinal arterial macroaneurysm. REPORT OF CASES: Case 1 was a 56-year-old woman, Case 2 was a 78-year-old man, and Case 3 was an 86-year-old man. In Cases 1 and 3, the fundus could not be observed visually at the time of initial examination because of vitreous bleeding. Retinal arterial macroaneurysm was revealed during vitrectomy. In Case 2, retinal arterial macroaneurysm was found on the optical disc along with a retinal hemorrhage which disappeared without any treatment. In all three cases, visual acuity was normal after treatment. CONCLUSIONS: Since retinal arterial macroaneurysm on the optical disc may be overlooked when treating vitreous bleeding in cases where the cause is not known, we believe that retinal arterial macroaneurysm should be taken into consideration as a possible underlying cause. While photocoagulation of retinal arterial macroaneurysm on the optic disc is infrequently used to, localized photocoagulation retinal arterial macroaneurysm on the optic disk is considered to be difficult. We are of the opinion that progression should be observed carefully till the macroaneurysm is absorbed.

Improvement of central retinal sensitivity six months after topical isopropyl unoprostone in patients with retinitis pigmentosa.

AIMS: Isopropyl unoprostone (IU), a maxi-K channel activator, is used topically to treat glaucoma, and has been reported to have neuroprotective effects on retinal neurons in vitro and in vivo. The purpose of this non-comparative pilot study was to determine whether topical IU will alter the sensitivity of the central retina in patients with retinitis pigmentosa (RP). SETTINGS AND DESIGN: Non-comparative pilot study. MATERIALS AND METHODS: IU was given topically twice a day for 6 months to both eyes of 30 patients with typical RP. The visual acuity was measured with a Japanese Snellen chart, and the mean retinal sensitivities were obtained by fundus-related microperimetry (MP-1). The mean deviation (MD) of the visual field was determined with a Humphrey field analyzer (HFA). All measurements were made before and 6 months after the treatment. STATISTICAL ANALYSIS USED: Wilcoxon and the Mann-Whitney U tests (SPSS, SPSS Inc., Chicago, IL). RESULTS: After the treatment, the mean retinal sensitivity within the central 2° and 10° improved significantly from 12.3 ± 4.8 dB to 14.7 ± 5.5 dB (P = 0.001) and from 9.1 ± 5.4 dB to 11.0 ± 6.2 dB (P = 0.001), respectively. CONCLUSIONS: These short-term results suggest topical IU can improve the central retinal sensitivity in RP patients. It will be necessary to examine longer treatment periods in a controlled study to determine the effectiveness of topical IU in RP patients.

Evaluation of contrast visual acuity in patients with retinitis pigmentosa.

BACKGROUND: The purpose of this study was to determine visual acuity at different contrast levels under photopic and mesopic conditions in patients with retinitis pigmentosa. METHODS: Sixty eyes of 31 normal controls, 92 eyes of 52 patients with retinitis pigmentosa without other ocular disorders (RP-1 group), and 20 eyes of 14 patients with retinitis pigmentosa with cataracts and without other ocular disorders (RP-2 group) were studied. Conventional visual acuity was measured using a conventional Landolt ring chart with 100% contrast and luminance of 150 cd/m(2). All of the patients with retinitis pigmentosa had a decimal visual acuity better than 1.0. Contrast visual acuity was measured with the same Landolt ring chart with contrasts of 100% and 10% and under photopic (200 cd/m(2)) and mesopic (10 cd/m(2)) conditions. Decimal visual acuities were converted to logMAR units for the analyses. RESULTS: The 100% contrast visual acuity and the 10% contrast visual acuity determined under both photopic and mesopic conditions were significantly poorer in both the RP-1 and RP-2 groups than in the controls. The differences between the conventional visual acuity and the 100% contrast visual acuity were significantly greater in the RP-1 and RP-2 groups than in the controls under both photopic and mesopic conditions. The differences between the 100% contrast visual acuity and the 10% contrast visual acuity were not significant among the three groups under photopic and mesopic conditions. CONCLUSION: Contrast visual acuities were greatly reduced in patients with retinitis pigmentosa with relatively well preserved conventional visual acuity, and the contrast visual acuity was largely influenced by ambient light levels in patients with retinitis pigmentosa. Although a longitudinal study for confirmation has to be performed, our findings indicate that contrast visual acuity is a better test to follow changes in visual function in patients with retinitis pigmentosa.

Macular abnormalities in patients with retinitis pigmentosa: prevalence on OCT examination and outcomes of vitreoretinal surgery.

PURPOSE: To determine the prevalence of macular abnormalities detected by optical coherence tomography (OCT) in patients with retinitis pigmentosa (RP), and to report the results of pars plana vitrectomy (PPV) in five patients with RP. METHODS: OCT images of the macula of 622 eyes of 323 patients with RP were evaluated. All patients had a complete clinical examination, and PPV was performed on two RP patients with a macular hole (MH), two patients with vitreomacular traction (VMT) syndrome, and one patient with cystoid macular oedema (CME). RESULTS: A macular lesion was detected by OCT in 46 eyes (7.4%) of 37 patients (11.5%). CME was detected in 34 eyes (5.5%) of 26 patients, an epiretinal membrane in four eyes of four patients, VMT in five eyes of four patients, and full-thickness MH in three eyes of three patients. PPV was performed on five of these eyes. The MH was closed with vision improvement after a single surgery in one eye, and was closed after repeated PPVs with a decrease of vision in another eye. In both patients with VMT, the visual acuity decreased after the surgery. The macular morphology and visual acuity did not improve postoperatively on the one patient with CME who underwent PPV. CONCLUSION: When OCT is used, macular abnormalities are present in 7.4% of patients with RP, which is lower than the prevalence reported earlier. Although vitrectomy can improve the macular morphology in some patients with RP, improvement of visual function may be limited most likely because of the long-standing retinal dysfunction.

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.

Changes in multifocal oscillatory potentials after internal limiting membrane removal for macular hole: multifocal OPs after ILM removal.

PURPOSE: To determine whether removal of the internal limiting membrane (ILM) during macular hole (MH) surgery alters the retinal function. METHODS: Multifocal electroretinograms (mfERGs) were recorded preoperatively and 3 months after surgery from 11 eyes of 10 patients with an idiopathic MH treated successfully by pars plana vitrectomy accompanied by ILM removal. A low frequency (9.4 Hz) pseudorandom binary m-sequence stimulus was used to elicit the mfERGs from different retinal loci. The bandpass of the amplifier was set at 10-300 Hz to record the mfERGs and at 100-300 Hz to record the oscillatory potentials (OPs). RESULTS: An anatomical closure of the MH was achieved in all patients, and the mean visual acuity was significantly improved postoperatively. No significant difference was observed in both the amplitudes and implicit times of the negative and positive waves of the mfERGs and the OPs recorded preoperatively to those recorded postoperatively. CONCLUSIONS: MH surgery with ILM removal does not alter the electrophysiological function of both the outer and inner retina of the posterior pole where the ILM was removed.

Built-in LED contact lens electrode for S-cone electroretinographic recordings.

PURPOSE: To characterize the cone electroretinograms (ERGs) elicited by chromatic stimuli obtained from a newly-developed contact lens electrode with built-in light-emitting diodes (LEDs) emitting different colors. METHODS: Cone ERGs were recorded from normal subjects with a contact lens electrode with built-in blue (430 nm), red (644 nm), and white LEDs. These LEDs have a wide range of luminance intensities (3 log units), and can be used as either the background illumination or the stimulus in any combination. The stimulus duration was fixed at 1 ms. For comparison, cone ERGs were recorded with Ganzfeld color flash stimuli using Wratten color filters on a bright white background. RESULTS: With a bright background illumination provided by the white LED (2.0 log cd/m2), the blue LED stimulus elicited an ERG with two positive peaks similar to that recorded with conventional Ganzfeld blue flashes. The peak time of the early b-wave was 24 to 28 ms, and that of the later one was 43 to 48 ms, and these values were identical to the L,M-cone and S-cone b-wave, respectively, elicited by Ganzfeld flashes. The ERGs elicited by the red LED lacked the second peak. CONCLUSION: These results indicate that the S-cone and L,M-cone ERGs can be recorded simultaneously under the same background with this contact lens electrode. This relatively simple technique can be used to examine the human S-cone system in a routine clinical setting.

Selective reduction of S-cone response and on-response in the cone electroretinograms of patients with X-linked retinoschisis.

PURPOSE: To examine the electroretinograms (ERGs) of the short-wavelength-sensitive (S-) and the mixed long- and middle-wavelength-sensitive (L,M-) cones, and the ON- and OFF-responses of the cone ERGs in three patients with X-linked juvenile retinoschisis (XLRS). METHODS: Cone ERGs elicited by different color flashes and those elicited by long duration stimuli under Ganzfeld conditions were recorded from three patients with XLRS. RESULTS: The S-cone b-waves were undetectable to short-wavelength stimuli in all three XLRS patients, while the L,M-cone ERG b-waves were within the normal range. To long-duration white stimuli, the ON-response (b-wave) was reduced and delayed in all patients compared with that of the normal subjects, while the d-wave or OFF-response appeared normal in amplitude and implicit time. CONCLUSIONS: These results support the hypothesis that the normal S-cone ERG arises primarily from the ON-pathway of the cone ERGs and the hypothesis that ON-bipolar cells are predominant in the S-cone system.

Morphological and functional changes of the macula after vitrectomy and creation of posterior vitreous detachment in eyes with diabetic macular edema.

The purpose of this study was to determine the morphological and functional changes in the macula after pars plana vitrectomy with the creation of a posterior vitreous detachment in eyes with diabetic macular edema (DME). A simple posterior vitreous detachment was created during pars plana vitrectomy accompanied by simultaneous cataract surgery in 19 eyes of 17 patients with DME. The visual acuity (log MAR units), multifocal electroretinograms (mfERGs), and optical coherence tomographically (OCT)-determined foveal thickness were determined preoperatively and at 6 months postoperatively. The median preoperative log MAR visual acuity was 0.7 (20/100; range, 0.3-1.1), and it improved significantly to 0.4 (20/50; range, 0.15-1.0) postoperatively (p = 0.016). The median foveal thickness was 510 (range, 194-800) microm preoperatively and was significantly reduced to 201 (range, 60-631) microm postoperatively (p =0.0002). The median of response density of the mfERGs in the macular area was 6.3 nV/ deg2 (range, 2.8-14.8) preoperatively, and 6.1 nV/deg2 (range, 2.4-14.3) postoperatively, a non-significant change (p = 0.27). The median of peak latency of the macular response was 30.0 ms (range, 25.0-44.2) preoperatively and it decreased significantly to 28.3 ms (range, 26.7-35.0) postoperatively (p = 0.003). In conclusion, vitrectomy with the creation of a PVD in eyes with DME improved the visual acuity and foveal thickness significantly. In addition, a decrease of the peak latency of the macular mfERGs suggested an improvement of the physiological function of the macula although the amplitude of the mfERGs was not changed significantly.