Features of abnormal choroidal circulation in central serous chorioretinopathy.

AIMS: To evaluate abnormalities in the choroidal circulation in cases of central serous chorioretinopathy (CSC). METHODS: A complete clinical ophthalmological examination was performed using simultaneous fluorescein and indocyanine green (ICG) angiography with a confocal scanning laser ophthalmoscopy and the digital images analysed in 36 consecutive patients with acute CSC. To quantify the choroidal circulation, the foveal choroidal blood flow was measured in 11 patients using laser Doppler flowmetry. RESULTS: Fluorescein angiography showed focal leakage from the retinal pigment epithelium in all patients. ICG angiography revealed delays in arterial filling in 27 eyes (75%), and fluorescein angiography showed small hypofluorescent points around the leakage in 27 eyes (75%). Abnormal choroidal hyperfluorescence was observed in 30 eyes (83%). The choroidal blood flow in eyes with CSC was 45% lower than in fellow eyes (p<0.01). CONCLUSION: Decreased choroidal blood flow in CSC was demonstrated for the first time. The decreased choroidal blood flow might be correlated with the small, localised hypofluorescent areas, which may indicate non-perfused areas of the choriocapillaris that are frequently seen during ICG angiography.

Scotoma and fixation patterns using scanning laser ophthalmoscope microperimetry in patients with macular dystrophy.

PURPOSE: We used scanning laser ophthalmoscope microperimetry to evaluate the retinal scotoma and the fixation points in the patients with macular dystrophy. METHODS: We studied 10 eyes of five patients with macular dystrophy (three patients with cone dystrophy and two patients with Stargardt disease). The mean patient age was 37 years (range, 13 to 64 years). An estimation of scotoma and fixation points on the retina was performed using scanning laser ophthalmoscope microperimetry. RESULTS: All 10 eyes (100%) had one of two types of dense scotoma: type one was a dense ring scotoma (five eyes, 50%), and type two was a dense central scotoma (five eyes, 50%) that included the center of the fovea. In all eyes with a dense ring scotoma, the fixation points were stable and did not shift. In all eyes with a dense central scotoma, the fixation shifted. The logarithm of minimal angle of resolution of the visual acuity in the eyes with the dense central scotoma was significantly worse than that of eyes with the dense ring scotoma type (P =.005). CONCLUSIONS: Scanning laser ophthalmoscope microperimetry findings demonstrate two types of dense scotoma (dense ring scotoma and dense central scotoma) in the patients with macular dystrophy. The two types of dense scotoma affect the shifting of the fixation points and the stability of fixation and may result in the difference in visual acuity in the patients with macular dystrophy.

Variations of Weiss's ring.

BACKGROUND: Weiss's ring is an important index for diagnosing a posterior vitreous detachment (PVD). The authors studied the configurations of Weiss's ring because the ring has several variations. METHODS: Weiss's ring was examined biomicroscopically in 223 eyes with PVD and documented videographically using a scanning laser ophthalmoscope. The configurations of Weiss's ring were classified into four groups: a complete ring, a partial ring, a ball-like opacity, and a hole without a ring. RESULTS: In the 223 eyes with PVD, Weiss's ring was categorized as a complete ring in 63 eyes (28.3%), a partial ring in 128 eyes (57.4%), a ball-like opacity in 17 eyes (7.6%), and a hole without a ring in 15 eyes (6.7%). A complete ring was observed in 8 (57.1%) of 14 eyes with hyperopia (+3 diopters or more), in 25 (28.7%) of 87 eyes with emmetropia (between -1 and +1 diopter), and in 10 (16.1%) of 62 eyes with myopia (-3 diopters or more). Six months after the initial examinations, the contour of Weiss's ring remained unchanged in 86 (96.6%) of 89 eyes with fresh PVD. CONCLUSIONS: Scanning laser ophthalmoscope is a useful tool for observing Weiss's ring. A "classic" annular opacity around a hole in the prepapillary posterior vitreous cortex represents less than one third of the configurations of Weiss's ring, indicating that the term "ring" is erroneous.

Stereo acuity in patients with unilateral macular hole and after unilateral macular hole surgery.

PURPOSE: To investigate stereo acuity levels in patients with unilateral idiopathic macular hole and after surgical intervention. METHODS: In 31 consecutive patients with a unilateral macular hole and 46 consecutive patients who underwent successful unilateral macular hole surgery, complete ocular examinations, including orthoptic examinations and microperimetry using the scanning laser ophthalmoscope, were performed. RESULTS: A significantly positive correlation was found between VA and stereo acuity (r = 0.87, P < 0.01). After successful surgery, stereo acuity also correlated with the presence or absence of absolute and/or relative scotoma, and was best in eyes without scotomata. Patients with unilateral idiopathic macular hole, suppression, and symptom duration of 24 months or longer had no stereoscopic vision. CONCLUSIONS: The results indicated that in patients with unilateral idiopathic macular hole and after surgery, stereo acuity correlated with VA. Patients with unilateral macular hole should be operated upon as early as possible, resulting in better VA and better stereo acuity.

Pulsatile ocular blood flow study: decreases in exudative age related macular degeneration.

BACKGROUND: Pulsatile ocular blood flow (POBF) is a parameter for evaluating choroidal blood flow. POBF in the patients with non-exudative and exudative age related macular degeneration (AMD) was investigated. METHODS: POBF, pulse amplitude (PA), systolic and diastolic blood pressures, intraocular pressure (IOP), refractive error, and axial length were compared among 10 patients with non-exudative AMD, 11 patients with exudative AMD, and 69 age matched controls. A Langham OBF computerised tonometer was used with the participants in the sitting position to measure POBF and PA. RESULTS: No significant differences were found in age, systolic and diastolic blood pressures, IOP, or refractive error between patients with exudative and non-exudative AMD and the control subjects. In the patients with exudative AMD the POBF (median, 372.7 microl/min) and PA (median, 1.2 mm Hg) were significantly lower than in the patients with non-exudative AMD (median, 607.0 microl/min (p = 0.02) and 2.2 mm Hg (p = 0.04), respectively) and control subjects (median, 547.4 microl/min (p = 0.01) and 2.0 mm Hg (p = 0.01), respectively). CONCLUSIONS: These data show that the POBF and PA in the patients with exudative AMD are lower than in the patients with non-exudative AMD and normal subjects. Decreased choroidal blood flow may have a role in the development of choroidal neovascularisation in AMD.

Factors affecting pulsatile ocular blood flow in normal subjects.

BACKGROUND: The factors that influence pulsatile ocular blood flow (POBF) were evaluated in normal subjects. METHODS: POBF was measured in 80 normal subjects using Langham OBF computerised tonometry. The effect of age, systolic and diastolic blood pressure, refractive error, intraocular pressure, and axial length on POBF was evaluated using multiple regression analysis. RESULTS: The mean (SD) POBF value was 593.3 (203.6) microl/min (range 290.7-1201.6). Of all the independent variables in the model, only the axial length was statistically significant (p = 0.008). The regression coefficient was negative, indicating that the axial length decreased with increasing POBF. CONCLUSIONS: These data suggest that, in normal subjects, the POBF decreases as axial length increases. Choroidal blood flow may decrease as the axial length increases. The axial length may therefore be a major factor affecting POBF.

Corneal advanced glycation end products increase in patients with proliferative diabetic retinopathy.

OBJECTIVE: To evaluate corneal advanced glycation end product (AGE) fluorescence in patients with diabetes and in healthy control subjects. RESEARCH DESIGN AND METHODS: Corneal autofluorescence was measured in 26 eyes of 26 patients with type 2 diabetes (mean age 57.0 years; mean disease duration 12.2 years; mean HbA1c 7.1%) and 13 eyes of 13 healthy age-matched control subjects (mean age 57.9 years). The patients with type 2 diabetes were divided into the following groups: patients without diabetic retinopathy (DR), patients without proliferative diabetic retinopathy (PDR), and patients with PDR. Corneal autofluorescence was measured by fluorophotometry with the wavelength that is characteristic of AGE fluorescence (excitation and emission 360-370 nm and 430-450 nm, respectively). We defined peak corneal autofluorescence levels as corneal AGE fluorescence values. We compared the corneal AGE fluorescence values in the four groups. RESULTS: In the PDR group (11.9 +/- 3.9 arbitrary units [mean +/- SD]), the corneal AGE fluorescence values were significantly higher compared with the control subjects (6.9 +/- 1.3 arbitrary units), the patients without DR (7.4 +/- 2.1 arbitrary units), and the patients without PDR (6.9 +/- 2.2 arbitrary units) (P < 0.05). CONCLUSIONS: We found that corneal AGEs may increase in patients with diabetes and PDR compared with control subjects, patients without DR, and patients without PDR. In the patients with PDR, increased corneal AGEs may play a role in diabetic keratopathy.

Changes in blood-retinal barrier permeability in form deprivation myopia in tree shrews.

To study the correlation between blood-retinal barrier (BRB) permeability and development of form deprivation (FD) myopia, FD was induced in tree shrews. The refractive error and the axial dimensions of the optical elements were measured. Ocular fluorescence was measured before and after fluorescein-Na injection. The inward permeability (P(in)) of the BRB was measured before and 15, 30, and 45 days after FD was induced. FD eyes became significantly myopic 15 days after FD was induced (P<0.01), and myopia progressed 45 days after FD was induced compared with untreated controls. Neither anterior chamber length nor lens thickness changed significantly. The vitreous chamber in FD eyes, however, was significantly elongated from 15 days after FD was induced (P<0.01) compared with controls. The P(in) ratio (P(in) [FD eye]/P(in) [untreated control]), increased significantly 45 days after FD was induced (P<0.05). In FD myopia in tree shrews, the BRB permeability increases abnormally. Impaired BRB function might be a secondary effect of myopia development rather than the cause of myopia.

Scanning laser ophthalmoscope correlations with biomicroscopic findings and foveal function after macular hole closure.

OBJECTIVE: To investigate the relation between foveal findings and visual function in eyes with a resolved idiopathic macular hole after vitreous surgery. METHODS: We divided 28 eyes with postoperative idiopathic macular hole resolution into 3 groups based on postoperative biomicroscopic foveal findings of complete closure, partial closure, or atrophic closure. To evaluate foveal retinal function, scanning laser ophthalmoscope (SLO) microperimetry was performed preoperatively and 6 months postoperatively. RESULTS: Postoperatively in 18 eyes (64%), the foveal images became normal or almost normal and were classified as having complete closure, 6 eyes (21%) were classified as having partial closure, and 4 eyes (14%) as having atrophic closure. The corresponding visual acuity levels 6 months postoperatively were, respectively, 0.10, 0.35, and 0.64 (P<.01) based on LogMAR analysis. Preoperative SLO microperimetry detected an absolute scotoma at the bottom of all macular holes; postoperatively, the absolute scotoma disappeared in the 18 eyes with complete hole closure, but a relative scotoma was detected in 6 eyes. Of 6 eyes with partial closure, 1 had an absolute scotoma and 5 had a relative scotoma. An absolute scotoma was detected in 4 eyes with atrophic closure. CONCLUSIONS: After macular hole closure, SLO findings correlate both with biomicroscopic findings and foveal function. Better anatomical foveal recovery in eyes after macular hole closure results in better improvement of vision than in eyes in which the foveal anatomical findings are not as good.

[Effect of topical levobunolol on retinal, optic nerve head, and choroidal circulation in normal volunteers].

PURPOSE: Using three different techniques of ocular blood flow measurement, we evaluated the effects of topical levobunolol on retinal, optic nerve head, and choroidal circulation. METHODS: Twenty normal volunteers received one drop of levobunolol in one eye and one drop of placebo in the fellow eye. Retinal venous blood flow was measured using multiple scattering laser velocimetry. Retinal capillary blood flow and optic nerve head blood flow were measured by Heidelberg Retina Flowmeter. Pulsatile ocular blood flow was measured by ocular blood flow tonography. Changes in blood pressure, heart rate, retinal venous blood flow, retinal capillary blood flow, optic nerve head blood flow, intraocular pressure and pulsatile ocular blood flow were detected from measurements taken at baseline and at 90 to 120 minutes following the instillation. RESULTS: Intraocular pressure decreased significantly in both eyes. Retinal capillary blood flow increased significantly in both eyes. Optic nerve head blood flow increased significantly in treated eyes but remained unchanged in placebo eyes. There were no significant changes in retinal venous blood flow or pulsatile ocular blood flow in either eyes. CONCLUSION: Our results suggest that one administration of levobunolol may increase the retinal and optic nerve circulation but does not decrease the choroidal circulation.

Oral fluorescein angiography with the confocal scanning laser ophthalmoscope.

OBJECTIVE: To evaluate the efficacy of oral fluorescein angiography with a confocal scanning laser ophthalmoscope (SLO) system. DESIGN: Comparative case series. PARTICIPANTS: The authors used a confocal SLO (Heidelberg Retina Angiograph [HRA]) to perform oral fluorescein angiography in 47 patients, 13 of whom were without any retinal disease and 34 with a variety of retinal diseases including macular holes and pucker, inflammatory diseases, retinal vascular diseases, and age-related macular degeneration. The images were also compared to images taken with a fundus camera after intravenous fluorescein injections in patients on whom both studies were done. INTERVENTION: Color fundus photographs were taken of each eye (30 degrees fundus camera) before drinking 4 ml of 25% sodium fluorescein mixed with 60 ml of orange juice. After oral fluorescein ingestion, images of each eye were taken with a fundus camera (TriX film) and the HRA (using 512- x 512-pixel resolution). The images were repeated at 0-, 2.5-, 5-, 7.5-, 10-, 12.5-, 15-, 20-, 25-, and 30-minute intervals. Twenty of the 47 patients underwent intravenous fluorescein angiography performed with the fundus camera. MAIN OUTCOME MEASURE: Images were analyzed by a masked reader, and foveal avascular zone visualization, branch retinal vessel identification, and image quality were scored. Statistical analysis was performed with a t test for paired data with a two-tailed test of significance (alpha = 0.05). RESULTS: Foveal avascular zone was 100% as seen in 16 eyes (47%) in the HRA machine versus 1 eye (2%) in the conventional fundus camera (P < 0.0001). The third-order branch retinal vessels were identified in 59% of eyes in the HRA versus 26% in the fundus camera group (P < 0.0001), and the image quality was considered comparable to an intravenous angiogram in 47% with the HRA versus 9% with the conventional fundus camera (P < 0.0001). CONCLUSIONS: Oral fluorescein angiography using the HRA produces sufficiently detailed images to diagnose, treat, and follow many types of retinal pathology.

Relationship between autofluorescence and advanced glycation end products in diabetic lenses.

Autofluorescence and advanced glycation end product (AGE) levels were measured in the lenses of 9 diabetic Chinese hamsters and 6 age-matched controls. Lens autofluorescence also was measured in 37 diabetic patients and 14 age-matched controls. Lens autofluorescence values were measured noninvasively with a lens measurement system using color filters with peak transmission at 365- and 434-nm wavelengths (excitation and emission, respectively) that are characteristic of AGE fluorescence. The peak lens autofluorescence level was used as the lens autofluorescence value, and the mean lens autofluorescence values from both eyes of each subject were used for statistical analysis. The AGE levels in one lens from each hamster were measured by noncompetitive enzyme-linked immunosorbent assay with a polyclonal anti-AGE antibody. We found a 2.2 times increase of the mean lens autofluorescence value of diabetic hamsters in comparison with that of controls (P<0.01). We also found a 1.5 times increase of the mean AGE level from the lenses of diabetic hamsters in comparison with that of controls (P<0.01). Moreover, a statistically significant positive correlation between the AGE level and autofluorescence value in the same lenses was observed in all hamsters (rho=0.58, P<0.05). In human subjects, we found a 1.4 times increase of the mean lens autofluorescence value of diabetic patients in comparison with that of age-matched controls (P<0.01). Our results suggest that non invasive measurement of lens autofluorescence may be a guide to AGE levels in lenses.

Corneal and lens autofluorescence in young insulin-dependent diabetic patients.

To study the early ocular abnormalities in young diabetic patients, corneal and lens autofluorescence was measured by fluorophotometry in 30 eyes of 30 insulin-dependent diabetic patients without retinopathy. The lens [f(l)] and the corneal [f(c)] autofluorescence values in diabetic patients were significantly higher than in controls. In diabetic patients, f(l) was significantly correlated with the duration of diabetes, the f(c) was significantly correlated with the duration of diabetes and the indices of metabolic control, i.e. HbA1c and fructosamine. Our study demonstrated that young diabetic patients clearly had corneal and lens abnormalities before the appearance of overt diabetic retinopathy. The f(c) value might be a good indicator of metabolic control in diabetic patients.

Radiating retinal folds detected by scanning laser ophthalmoscopy using a diode laser in a dark-field mode in idiopathic macular holes.

BACKGROUND: The pathogenesis of idiopathic macular hole is unclear. We studied the morphologic features of idiopathic macular holes using a modification of the scanning laser ophthalmoscope (SLO). METHODS: Seventy-two eyes of 57 patients with macular hole (40 women, 17 men; age 66.1 +/- 6.4 years, mean +/- SD) were included in this study. The macular holes were classified according to the Gass classification (1988). The changes around the macular holes were recorded by SLO using both a confocal aperture with a helium-neon laser (633 nm) and a ring aperture (dark-field mode) with a diode laser (780 nm) to detect fine morphologic features. RESULTS: We successfully observed minute retinal wrinkling, i.e., radiating striae (fold type) and a dome configuration (dome type), around the macular holes using the SLO dark-field mode with a diode laser, which provides a deeper retinal image because of the longer wave-length laser and the indirect mode. A helium-neon laser with a confocal aperture sometimes failed to disclose the fine retinal wrinkles. Most of the stage 2 macular holes were of the fold type. The smaller the hole, the higher the prevalence of the fold type. As the holes progressed in size, the prevalence of the dome type increased. The radiating retinal folds disappeared after successful vitreous surgery. CONCLUSION: The SLO dark-field mode with a diode laser might be useful for clear observation of fine retinal features around macular holes. The retinal folds probably indicate the presence of traction on the macula and hence may be good markers for macular repair after vitreous surgery.

The use of scanning laser ophthalmoscope microperimetry to detect visual impairment caused by macular photocoagulation.

BACKGROUND AND OBJECTIVE: To demonstrate the effectiveness of scanning laser ophthalmoscope (SLO) microperimetry in detecting retinal sensitivity and in describing areas of unstable fixation following photocoagulation therapy. PATIENTS AND METHODS: Two patients with iatrogenic vision loss resulting from photocoagulation therapy underwent a fundus examination, SLO microperimetry, and fluorescein angiography. One patient also underwent indocyanine green angiography. RESULTS: Two types of visual acuity decrease--sudden-onset and late-onset--were demonstrated following macular photocoagulation, the former resulting from incorrect identification of the fixation point, and the latter from enlarging photocoagulation scars placed in close proximity to the fovea. In one case, SLO microperimetry detected dense scotoma corresponding to the patient's symptoms and an unstable fixation point. In the other case, different retinal sensitivities were found in the photocoagulation scars. No differences were found with fluorescein angiography or indocyanine green angiography. CONCLUSION: SLO microperimetry might be effective for quantitative assessment of retinal sensitivity in photocoagulation scars and for detecting fixation points and determining their stability.

Comparison of short- and long-term effects of betaxolol and timolol on human retinal circulation.

PURPOSE: To determine the short- and long-term effects of betaxolol and timolol on human retinal circulation. METHODS: In a double-masked, randomised, placebo-controlled study we evaluated the effects of both a one-drop application and a twice-daily 2-week application of either topical 0.5% betaxolol hydrochloride or topical 0.5% timolol maleate on the retinal circulation in 12 healthy volunteers. Laser Doppler velocimetry was used to detect changes in the retinal venous blood flow. RESULTS: In both betaxolol- and timolol-treated eyes, intraocular pressure decreased significantly compared with baseline values after both 90 min and 2 weeks. In betaxolol-treated eyes, retinal blood flow did not change significantly after 90 min, but increased significantly (14 +/- 9%; p = 0.02) compared with baseline after 2 weeks. In timolol-treated eyes, retinal blood flow decreased significantly (18 +/- 5%: p = 0.04) compared with baseline after 90 min, and also decreased significantly (14 +/- 6%; p = 0.04) compared with baseline after 2 weeks. CONCLUSIONS: Retinal blood flow increases as a long-term effect of betaxolol and decreases as both a short- and long-term effects of timolol.