Evaluation of radial optic neurotomy for central retinal vein occlusion by indocyanine green videoangiography and image analysis.

PURPOSE: To evaluate the effects of radial optic neurotomy (RON) on retinal circulation in patients with central retinal vein occlusion (CRVO) by indocyanine green (ICG) videoangiography and a computer-assisted image analysis. DESIGN: An interventional case series. METHODS: RON was performed in 15 eyes of 15 patients with CRVO. Within 72 hours before the surgery and at 3 months after the surgery, ICG videoangiography was performed with a scanning laser ophthalmoscope, and the images were transferred to a computer. Two measurement points were selected, one on a main retinal artery close to the optic disk and the other on the corresponding retinal vein. At each point, fluorescence intensities were serially measured, and dye dilution curves were obtained. Retinal circulation times (DeltaT(50)) before and after the surgery were calculated. RESULTS: Mean preoperative DeltaT(50) was 6.46 +/- 1.36 seconds, and mean postoperative DeltaT(50) was 6.80 +/- 2.50 seconds. In 8 of 15 eyes, T(50) decreased by 6.8% to 29.6% after the surgery. In the seven eyes that developed chorioretinal anastomosis (CRA) at the site of RON, DeltaT(50) decreased after the surgery. In contrast, DeltaT(50) decreased postoperatively in only one of the eight eyes without CRA. Best-corrected visual acuity improved significantly after the surgery in the group of eyes with improvement in DeltaT(50), but not in the group of eyes without improvement in DeltaT(50). CONCLUSIONS: Some degree of retinal circulation improvement occurred in approximately half of these eyes, which appears to be correlated with the development of CRA.

Time-frequency analysis of electronystagmogram signals in patients with congenital nystagmus.

PURPOSE: To evaluate the usefulness of the short-time Fourier transform (STFT) in the analysis of temporal congenital nystagmus characteristics. METHODS: We carried out an observational case series in patients with congenital nystagmus. An electronystagmogram (ENG) recording was performed for 300 s in 13 consecutive subjects with congenital nystagmus (age: 7-68 years). Digitized ENG signals (12 bits, 100 Hz) were divided into 2-s segments with a Hanning window, and a Fourier transform was carried out for each segment. The power spectrum obtained for each segment was graphically reconstructed as a function of time. The results were compared among the patients. RESULTS: Clear periodicity in the time-frequency distribution was observed in 3 of the 13 patients (23%). One of the three patients was diagnosed with periodic alternating nystagmus, but the other two patients showed periodicity without alternation of beat direction. No significant difference was observed in clinical characteristics, except for sex, between patients who showed periodicity and those who did not. CONCLUSIONS: Some patients with congenital nystagmus showed clear periodicity in the nystagmus waveform without alternation of beat direction. The STFT is a useful tool to evaluate the temporal characteristics of congenital nystagmus in clinics.

Evaluation of arteriovenous crossing sheathotomy for branch retinal vein occlusion by fluorescein videoangiography and image analysis.

PURPOSE: We quantitatively evaluated the effects of arteriovenous (A/V) crossing sheathotomy on retinal circulation in patients with branch retinal vein occlusion (BRVO) accompanied by macular edema. DESIGN: Interventional case series. METHODS: In 18 consecutive patients (18 eyes) with BRVO accompanied by macular edema who underwent A/V crossing sheathotomy between August 1999 and April 2002, changes in retinal circulation after the surgery were evaluated by fluorescein videoangiography with a scanning laser ophthalmoscope and by image analysis using dye dilution technique. At a venule distal to the responsible A/V crossing site and a normal venule, the circulation time (T50) from the beginning of filling to 50% filling of the peak intensity was calculated. The time difference (DeltaT50) between T50 at the point on the affected venule and that at the point on the normal venule, which represents the filling delay at the venule distal to the A/V crossing site, was compared between before and early after the surgery. RESULTS: The preoperative DeltaT50 was 1.36 +/- 1.15 seconds (mean +/- SD), and the postoperative DeltaT50 was 0.72 +/- 0.77 seconds (P =.035, paired t test). In 11 of the 18 eyes, DeltaT50 decreased by 20% or more after the surgery. In the other 7 eyes, DeltaT50 was unchanged or slightly increased after the surgery. CONCLUSIONS: Although a randomized controlled study is needed to confirm the effectiveness of A/V crossing sheathotomy on visual function, this technique could be effective for improving the delay in perfusion in the affected venule.

Evaluation of the dynamics of choroidal circulation in experimental acute hypertensionusing indocyanine green-stained leukocytes.

PURPOSE: To evaluate the dynamics of choroidal circulation in experimental acute hypertension, using the indocyanine green leukocyte angiography (ILA) method, which the authors have developed for the evaluation of leukocyte dynamics in choroidal circulation. METHODS: Japan White rabbits were used in the present study. Leukocytes were collected by centrifugal separation of the autologous blood, and were stained with indocyanine green (ICG) dye. The ICG-stained leukocyte fluid was injected into an ear vein, and fundus images were obtained by infrared laser and a scanning laser ophthalmoscope. Experimental acute hypertension was induced by the intravenous drip injection of angiotensin II (AII). RESULTS: The fluorescent dots rapidly moved in choroidal arteries at a decreasing velocity, passed very slowly through choroidal capillaries and drained into choroidal veins. Under normal blood pressure, the mean leukocyte velocities in arteries, capillaries and veins were 8.63+/-1.68, 0.52+/-0.07, and 6.96+/-2.20 mm/s, respectively. On the other hand, the respective mean velocities in acute hypertension induced by AII were 13.50+/-1.82, 0.81+/-0.09, and 10.54+/-3.91 mm/s. Besides flow velocity, no change in leukocyte dynamics was observed. CONCLUSIONS: Under the condition of acute hypertension induced by AII, leukocytes moved faster in the total choroidal circulation (from arteries to veins) compared to their velocity under the condition of normal blood pressure. Blood velocities might increase in the total choroidal circulation at an early stage in acute hypertension induced by AII, resulting in increased choroidal blood flow. ILA makes it possible to evaluate the changes in choroidal circulation under various pathologic conditions.

Trehalose eye drops in the treatment of dry eye syndrome.

OBJECTIVE: Trehalose can protect human corneal epithelial cells in culture from death from desiccation. This study was designed to test the efficacy and safety of trehalose eyedrops in the treatment of moderate to severe dry eye syndrome. DESIGN: A randomized, double-masked, dose-ranging, fellow eye-controlled clinical trial. PARTICIPANTS: Thirty-four patients with moderate to severe dry eye syndrome. METHODS: The patients used either 100 or 200 mM trehalose dissolved in saline six times daily in one eye and control saline in the other eye for 4 weeks. MAIN OUTCOME MEASURES: Symptoms and signs in both eyes were recorded separately at baseline, 2 weeks, and 4 weeks. RESULTS: Fluorescein and rose bengal staining scores of the ocular surface improved at both 2 weeks and 4 weeks in the eyes with 100 and 200 mM trehalose, compared with eyes with control saline (P = 0.0030 to P < 0.0001, respectively, Mann-Whitney U test). Tear film breakup time became significantly longer at 2 weeks and 4 weeks with 100 mM trehalose (P = 0.0024 and P < 0.0001, respectively), but not with 200 mM trehalose. No adverse effect attributable to trehalose solution was noted. CONCLUSIONS: Trehalose solution was an effective and safe eyedrop for the treatment of moderate to severe dry eye syndrome in this group of patients.

Risk factors for diabetic choroidopathy in patients with diabetic retinopathy.

PURPOSE: To identify risk factors for diabetic choroidopathy in patients with type 2 diabetes. METHODS: Forty-five consecutive patients with diabetic retinopathy underwent simultaneous indocyanine green angiography (ICG) and fluorescein angiography using a double detector and confocal scanning laser ophthalmoscopy in both eyes. Choroidal vascular abnormalities were evaluated by comparing the angiographic findings derived from the two methods. We analyzed the association between the presence of abnormal choroidal lesions evident on ICG angiography and several risk factors. RESULTS: Choroidal abnormalities evident on ICG angiography but not on fluorescein angiography included hypofluorescent spots in 72 eyes (80%) of 40 patients (89%), small hyperfluorescent spots in 61 eyes (68%) of 35 patients (78%), and large hyperfluorescent spots in 32 eyes (36%) of 21 patients (47%). The severity of diabetic retinopathy was significantly associated with the presence of hypofluorescent spots ( P=0.002, Cochran-Armitage test) in both eyes and with the small hyperfluorescent spots in the right eyes ( P=0.047, Cochran-Armitage test). Glycosylated hemoglobin levels were significantly associated with the large hyperfluorescent spots in the right eyes ( P=0.003, Fisher's exact probability test), and the treatment regimen was significantly associated with the small hyperfluorescent spots in the left eyes ( P=0.048, chi-square test). CONCLUSION: These data suggest that risk factors influencing the prevalence of diabetic choroidopathy in patients with type 2 diabetes mellitus may include severity of diabetic retinopathy, degree of diabetic control and treatment regimen.