Acute Effect of Hypervolemic Hemodilution on Retrobulbar Hemodynamics in Anterior Ischemic Optic Neuropathy.

PURPOSE: Ischemic ocular disorders may be treated by hypervolemic hemodilution. The presumed therapeutic benefit is based on a volume effect and improved rheological factors. The aim was to investigate the acute effect of intravenous hydroxyethyl starch on retrobulbar hemodynamics in patients with nonarteritic anterior ischemic optic neuropathy (NAION). METHODS: 24 patients with acute NAION were included. Retrobulbar hemodynamics were measured using color Doppler imaging before and 15 min after intravenous infusion of 250 cc 10% hydroxyethyl starch (HES). Peak systolic velocity (PSV), end diastolic velocity (EDV), and Pourcelot's resistive index (RI) were measured in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (PCAs). RESULTS: After infusion of HES blood flow velocities significantly increased in the CRA (PSV from 7.53 ± 2.33 to 8.32 ± 2.51 (p < 0.001); EDV from 2.16 ± 0.56 to 2.34 ± 0.55 (p < 0.05)) and in the PCAs (PSV from 7.18 ± 1.62 to 7.56 ± 1.55 (p < 0.01); EDV from 2.48 ± 0.55 to 2.66 ± 0.6 cm/sec (p < 0.01)). The RI of all retrobulbar vessels remained unaffected. Blood pressure and heart rate remained unchanged. CONCLUSIONS: Hypervolemic hemodilution has an acute effect on blood flow velocities in the CRA and PCAs in NAION patients. Increased blood flow in the arteries supplying the optic nerve head may lead to a better perfusion in NAION patients. This trial is registered with DRKS00012603.

Long term effect of trabeculectomy on retrobulbar haemodynamics in glaucoma.

PURPOSE: Previous reports showed increased flow velocities in retrobulbar vessels after glaucoma surgery in the first weeks. Colour Doppler imaging was performed to investigate the long-term effects of trabeculectomy on retrobulbar haemodynamics in patients with primary open-angle glaucoma (POAG). METHODS: In a prospective study 30 patients (mean age 63.2 ± 15.4 years) with POAG were included. Colour Doppler imaging was performed before 1-2 weeks, after 2 months, after 4-6 months, and up to 3 years after trabeculectomy to determine the peak systolic and end-diastolic velocities in the ophthalmic artery, central retinal artery, and the short nasal and temporal posterior ciliary arteries. RESULTS: Mean follow-up was 416 ± 246 days. In the first postsurgical period mean intraocular pressure (IOP) decreased after trabeculectomy from 25 ± 6 mmHg to 9 ± 4 mm Hg (p < 0.0001) and then increased in the further follow-up to 13 ± 3 mmHg (p < 0.05) without any anti-glaucomatous medication. Colour Doppler imaging revealed a significant increase of the end-diastolic velocities of the central retinal artery at all postoperative visits compared to pre-surgery (p < 0.003) and of the end-diastolic velocities in the temporal posterior ciliary arteries (p < 0.003). The change of blood flow parameters that increased during follow-up was significantly correlated to the change in ocular perfusion pressure and IOP. CONCLUSIONS: End-diastolic velocities of the central retinal artery and of the temporal posterior ciliary arteries increased after successful trabeculectomy and remained stable in a longer period - even if IOP rose significantly in the follow-up.

Arteriovenous passage times and visual field progression in normal tension glaucoma.

PURPOSE: Fluorescein angiographic studies revealed prolonged arteriovenous passage (AVP) times and increased fluorescein filling defects in normal tension glaucoma (NTG) compared to healthy controls. The purpose of this study was to correlate baseline AVP and fluorescein filling defects with visual field progression in patients with NTG. PATIENTS AND METHODS: Patients with a follow-up period of at least 3 years and at least 4 visual field examinations were included in this retrospective study. Fluorescein angiography was performed at baseline using a confocal scanning laser ophthalmoscope (SLO, Rodenstock Instr.); fluorescein filling defects and AVP were measured by digital image analysis and dye dilution curves (25 Hz). Visual field progression was evaluated using regression analysis of the MD (Humphrey-Zeiss, SITA-24-2, MD progression per year (dB/year)). 72 patients with NTG were included, 44 patients in study 1 (fluorescein filling defects) and 28 patients in study 2 (AVP). RESULTS: In study 1 (mean follow-up 6.6 ± 1.9 years, 10 ± 5 visual field tests), MD progression per year (-0.51 ± 0.59 dB/year) was significantly correlated to the age (P = 0.04, r = -0.29) but not to fluorescein filling defects, IOP, or MD at baseline. In study 2 (mean follow-up 6.6 ± 2.2 years, 10 ± 5 visual field tests), MD progression per year (-0.45 ± 0.51 dB/year) was significantly correlated to AVP (P = 0.03, r = 0.39) but not to age, IOP, or MD at baseline. CONCLUSION: Longer AVP times at baseline are correlated to visual field progression in NTG. Impaired retinal blood flow seems to be an important factor for glaucoma progression.

Retrobulbar blood flow and visual field alterations after acute ethanol ingestion.

BACKGROUND: The purpose of this study was to test the effect of ethyl alcohol on the koniocellular and magnocellular pathway of visual function and to investigate the relationship between such visual field changes and retrobulbar blood flow in healthy subjects. METHODS: In 12 healthy subjects (mean age 32 ± 4 years), color Doppler imaging, short-wavelength automated perimetry, and frequency doubling perimetry was performed before and 60 minutes after oral intake of 80 mL of 40 vol% ethanol. Mean and pattern standard deviations for short-wavelength automated and frequency doubling perimetry were assessed. End diastolic velocity (EDV) and peak systolic velocity (PSV) were measured in the central retinal and ophthalmic arteries using color Doppler imaging. Systemic blood pressure, heart rate, intraocular pressure, and blood alcohol concentration were determined. RESULTS: Mean PSV and EDV in the central retinal artery showed a significant increase after alcohol intake (P = 0.03 and P = 0.02, respectively). Similarly, we found a significant acceleration of blood flow velocity in the ophthalmic artery (P = 0.02 for PSV; P = 0.04 for EDV). Mean intraocular pressure decreased by 1.0 mmHg after alcohol ingestion (P = 0.01). Retinal sensitivity in short-wavelength automated perimetry did not alter, whereas in frequency doubling perimetry, the mean deviation decreased significantly. Systolic and diastolic blood pressure did not change significantly. Mean blood alcohol concentration was 0.38 ± 0.16 g/L. CONCLUSION: Although ethanol is known to cause peripheral vasodilation, our subjects had no significant drop in systemic blood pressure. However, a significant increase of blood flow velocity was seen in the retrobulbar vessels. Regarding visual function, moderate alcohol consumption led to reduced performance in the magnocellular visual system tested by frequency doubling perimetry, but had no effect on short-wavelength automated perimetry.

Tonometry in corneal edema after cataract surgery: dynamic contour tonometry versus Goldmann applanation tonometry.

INTRODUCTION: Intraocular pressure (IOP) determination using dynamic contour tonometry (DCT) has been considered to be independent of central corneal thickness (CCT), while Goldmann applanation tonometry (GAT) is known to be influenced by various corneal properties. In this study, IOP was measured before and 1 day after cataract surgery using GAT and DCT to investigate the possible effects of corneal edema on IOP measurements. METHODS: Thirty patients with advanced cataracts were included in a pilot study. IOP was measured using GAT and DCT before and 1 day after phacoemulsification. CCT was determined before and after surgery to quantify postsurgical corneal edema. RESULTS: CCT increased significantly (by 89.7 ± 107.4 µm, P < 0.0001) 1 day after surgery. No significant difference was found for IOP measurements using GAT and DCT before surgery (mean IOP GAT: 17.5 ± 5.7 mmHg; mean IOP DCT: 17.9 ± 6.4 mmHg; P = 0.67) and 1 day after surgery (mean IOP GAT: 16.1 ± 6.6 mmHg; mean IOP DCT: 16.8 ± 8.3 mmHg; P = 0.69). IOP values using GAT and DCT were significantly correlated before as well as 1 day after surgery (before surgery: r = 0.82, P < 0.0001; after surgery r = 0.83, P < 0.0001). Bland-Altman plots showed a high variability in the difference in IOP measurements between methods before and 1 day after surgery. CONCLUSION: GAT and DCT seem to be equally valuable in IOP determination in postsurgical central corneal edema, although large differences between both methods are present in individual patients. IOP evaluation in corneal edema remains a difficult clinical challenge.

Retrobulbar hemodynamics before and after oculopression with and without dorzolamide.

PURPOSE: To investigate the effect of intraocular pressure (IOP) reduction by oculopression and topical dorzolamide on retrobulbar hemodynamics. METHODS: Sixty patients (70 ± 8.5) solely with cataract diagnosis solely were included in this prospective study. Patients with other systemic and ocular diseases affecting ocular circulation were excluded. On 30 patients (71 ± 8.5), solely oculopression (Honan IOP reducer) was performed. The other half of the patients (69 ± 8.3) additionally received 2 h prior to oculopression additionally topical dorzolamide. Before and after oculopression, IOP was measured and color Doppler imaging (CDI) was performed for the ophthalmic artery (OA), the central retinal artery, and the short posterior ciliary arteries (PCA). Furthermore, blood pressure and heart rate were monitored. RESULTS: At baseline there was no significant IOP difference between both groups (p = 0.54). IOP, measured prior to oculopression, was significant lower (p < 0.0001) in the group treated with dorzolamide (15.2 mmHg) compared to the other group (17.8 mmHg). Oculopression then led to a significant IOP reduction in all patients (p < 0.0001). There was no significant difference of the delta of IOP reduction between both groups observed (p = 0.47). In either group CDI showed a significant increase of peak systolic velocity (PSV) (p < 0.0001) and end-diastolic velocity (EDV) (p < 0.0001) after oculopression in all vessels. In both groups ocular perfusion pressure increased significantly by 6% (p < 0.0001). After oculopression the PSV of the OA was significantly higher (14%; p < 0.0001) after dorzolamide application than after oculopression alone. Furthermore, in the group with oculopression and dorzolamide treatment EDV of the PCA was significantly higher (21%; p < 0.0001) and resistive index of the PCA was significantly lower (-5.6%; p = 0.001). CONCLUSION: IOP reduction by a pure mechanical procedure like oculopression leads to a significant increase of flow velocities of the retrobulbar vessels. This effect can significantly be increased by using dorzolamide prior to oculopression.

Optic disc fluorescein leakage and intraocular pressure in primary open-angle glaucoma.

PURPOSE: To investigate the relationship between increased fluorescein leakage of the optic nerve head and intraocular pressure (IOP), visual field defect, vertical cup-to-disc ratio, disc size and systemic blood pressure in primary open-angle glaucoma (POAG). METHODS: Twenty-seven patients with POAG (aged 63 ± 11 years) and 15 control subjects (aged 58 ± 9 years, p = 0.14) were included in a pilot study. Fluorescein angiography was performed using a Scanning Laser Ophthalmoscope (Rodenstock Instruments, Germany). Fluorescein leakage of the optic disc was quantified using digital image analysis. The change of optic disc fluorescence from 7-8 min to 9-10 min was calculated and correlated to IOP, visual field mean deviation (MD), vertical cup-to-disc ratio, disc size, mean arterial blood pressure (MAP) and ocular perfusion pressure. RESULTS: The change in optic disc fluorescein leakage was significantly increased in patients with POAG compared to control subjects (POAG: 9.7 ± 6.7%; controls: 3.4 ± 4.9%, p = 0.0025). In POAG, fluorescein leakage was significantly correlated to IOP (r = 0.42, p = 0.029), but not to MD (r = -0.13, p = 0.51), vertical cup-to-disc ratio (r = 0.11, p = 0.60) disc size (r = -0.22, p = 0.30), MAP (r = -0.16, p = 0.42) or ocular perfusion pressure (r = -0.32, p = 0.10). In control subjects, a significant correlation was found with vertical cup-to-disc ratios (r = 0.59, p = 0.034), but not to IOP (r = -0.07, p = 0.80), MD (r = -0.26, p = 0.42), disc size (r = -0.10, p = 0.76), MAP (r = 0.09, p = 0.77), or ocular perfusion pressure (r = 0.11, p = 0.72). CONCLUSION: Increased fluorescein leakage of the optic disc was associated with higher IOP levels in patients with POAG. This might reflect a link between vascular damage with increased permeability and uncontrolled IOP.

Ocular pulse amplitude before and after cataract surgery.

PURPOSE: To investigate the impact of cataract surgery on the association of the ocular pulse amplitude (OPA) and intraocular pressure (IOP) with respect to the interpretation of OPA as an estimate of ocular blood flow. METHODS: Twenty-four patients with cataract were included in a clinical study. OPA was measured using dynamic contour tonometry (DCT, Pascal(®), SMT Swiss Microtechnology AG, Switzerland). IOP was measured by means of Goldmann applanation tonometry (IOP GAT) and DCT (IOP DCT). All measurements were performed before and one day after cataract surgery. RESULTS: At baseline, OPA was correlated to IOP GAT (r = 0.67, P = 0.0002) and IOP DCT (r = 0.82, P < 0.0001), but not to age or axial length. Postoperative OPA was correlated to IOP GAT (r = 0.67, P = 0.0002) and IOP DCT (r = 0.65, P = 0.0004). In 17 patients, IOP GAT decreased after surgery (IOP DCT n = 14), whereas an increase was apparent in seven patients (IOP DCT n = 10). The mean absolute deviation of IOP GAT pre- to post-surgery was 4.54 mmHg ± 2.47 (range 1-10 mmHg) and 5.4 mmHg ± 3.2 (range 1.1-13.1 mmHg) for IOP DCT. The changes of OPA were significantly correlated to changes in IOP GAT (r = 0.48, P = 0.017) and IOP DCT (r = 0.60, P = 0.001). IOP GAT and IOP DCT changes were not correlated to changes in corneal thickness. CONCLUSIONS: The OPA measured with the Pascal(®) device seems to be dependent on IOP changes. Particular caution should be taken in the interpretation of OPA in estimating pulsatile ocular blood flow.

Fluorescein leakage of the optic disc: time course in primary open-angle glaucoma.

PURPOSE: To identify and quantify the time course of fluorescein leakage of the optic nerve head in primary open-angle glaucoma (POAG) and controls. METHODS: Twenty patients with POAG (aged 58 +/- 10 years) and 14 controls (aged 51 +/- 12 years, p = 0.07) were included in a prospective study. Fluorescein leakage of the optic disc was quantified using digital image analysis. A new leakage ratio (fluorescence of the optic disc divided by fluorescence of the surrounding retina) was defined and fluorescein leakage was quantified at 7-8, 9-10, 11-12, and 13-14 min after injection of 2.5 cc sodium fluorescein (10%). RESULTS: The fluorescein leakage exhibited a significantly different time course with higher leakage ratio values in POAG compared to controls (7-8 min: 1.24 +/- 0.32 vs 1.16 +/- 0.12; 9-10 min: 1.37 +/- 0.37 vs 1.19 +/- 0.1; 11-12 min: 1.38 +/- 0.36 vs 1.24 +/- 0.13; 13-14 min: 1.44 +/- 0.36 vs 1.27 +/- 0.13; p = 0.004). The change in optic disc fluorescence from 7-8 min to 9-10 min was significantly higher in POAG compared to controls (0.13 +/- 0.09 vs 0.03 +/- 0.07; p = 0.002). CONCLUSION: The time course of fluorescein leakage is significantly different in POAG compared to controls. This might reflect damage of the optic disc vasculature related to increased vascular permeability.

New treatment option for adult-onset limbal xanthogranuloma.

PURPOSE: The purposes of this study are to report a case of adult-onset juvenile xanthogranuloma and suggest a new treatment option. METHODS: A 35-year-old man presented with an isolated mass of the limbus. Biopsy revealed a histiocytic tumor with Touton's giant cells staining positive for CD68 and S-100 but negative for CD1a, consistent with JXG. Two intratumoral injections of triamcinolone acetonide 6 weeks apart were performed. The main outcome measure was 6-months follow up clinically and by ultrasound biomicroscopy. RESULTS: The lesion regressed, and corneal thickness returned to normal 3 months after the first injection. An increase in intraocular pressure required topical treatment. No recurrence was seen throughout follow up. CONCLUSION: Limbal juvenile xanthogranuloma can be successfully treated with intralesional triamcinolone acetonide, thus avoiding a lamellar keratectomy approach.

Recurrent suprachoroidal dislocation of an anterior chamber intraocular lens.

We present a patient with a history of posterior chamber intraocular lens (PC IOL) implantation and trabeculotomy 9 years previously who recently had IOL exchange for an angle-based anterior chamber IOL. Twenty-four hours after the exchange, he was referred to us with hypotony and "loss" of the IOL. Ultrasound revealed a rigid choroidal detachment and echoes suggestive of a suprachoroidally dislocated IOL. Anterior vitrectomy and resuturing of the incision were performed. Subsequently, the IOL repeatedly migrated in and out of the suprachoroidal space, allowing atraumatic removal. Angle-based IOL implementation should be avoided in eyes with a history of trabeculotomy or cyclodialysis.

Prolonged retinal arteriovenous passage time is correlated to ocular perfusion pressure in normal tension glaucoma.

BACKGROUND: The pathogenesis of normal tension glaucoma (NTG) might be related to impaired autoregulation of ocular blood flow. The purpose of the study is to evaluate retinal haemodynamics by fluorescein angiography and to correlate arteriovenous passage times (AVP) with ocular perfusion pressure in patients with NTG and controls. METHODS: Thirty-five patients with NTG without any topical treatment (mean age 53 +/- 11 years) and 35 age-matched controls (mean age 53 +/- 11 years) were included in this study. Retinal AVP was assessed by video fluorescein angiography using a scanning laser ophthalmoscope (Rodenstock, Germany). Dye dilution curves of temporal superior and inferior arterioles and venules were evaluated by digital image analysis. AVP was correlated to mean arterial blood pressure and ocular perfusion pressure. RESULTS: The AVP was significantly prolonged in patients with NTG compared to controls (1.82 +/- 0.57 versus 1.42 +/- 0.46, p = 0.002). Patients with NTG and controls showed no significant differences in intraocular pressure, mean arterial pressure and mean and diastolic ocular perfusion pressure. The AVP was significantly correlated to mean arterial pressure and mean and diastolic ocular perfusion pressure in patients with NTG (r = -0.54; p = 0.0006, r = -0.51; p = 0.002, r = -0.49, p = 0.002), but not in controls (r = -0.21; p = 0.23, r = -0.19; p = 0.27, r = 0.02, p = 0.93). CONCLUSIONS: Patients with NTG exhibit prolonged retinal AVP compared to controls. A significant correlation of retinal haemodynamics to mean arterial blood pressure and ocular perfusion pressure might reflect impaired autoregulation in NTG.

Dronabinol and retinal hemodynamics in humans.

PURPOSE: To investigate the effects of oral cannabinoids on retinal hemodynamics assessed by video fluorescein angiography in healthy subjects. DESIGN: Interventional study. METHODS: In a self-experiment, the cannabinoid dronabinol (delta-9-tetrahydrocannabinol [THC]) was administered orally to eight healthy medical doctors (7.5 mg Marinol; Unimed Pharmaceuticals, Chicago, Illinois, USA). At baseline and two hours after dronabinol intake, intraocular pressure (IOP) was measured and retinal hemodynamics were assessed by fluorescein angiography. The retinal arteriovenous passage time was determined on the basis of dye dilution curves by means of digital image analysis in a masked fashion. RESULTS: Dronabinol resulted in a significant IOP reduction from 13.2 +/- 1.9 mm Hg to 11.8 +/- 2.0 mm Hg (P = .038). The retinal arteriovenous passage time decreased from 1.77 +/- 0.35 seconds to 1.57 +/- 0.31 seconds (P = .028). Systemic blood pressure and heart rate were not statistically significantly altered. CONCLUSIONS: Cannabinoids, already known for their ability to reduce IOP, may result in increased retinal hemodynamics. This may be beneficial in ocular circulatory disorders, including glaucoma.

Retrobulbar haemodynamics and contrast sensitivity improvements after CO2 breathing.

PURPOSE: Effects of gas mixtures have been widely studied. Carbon dioxide (CO(2)) is known to act as a vasodilator, whereas oxygen (O(2)) acts as a vasoconstrictor. Therefore, the interpretation of results is difficult. In this study, only the effect of an elevated CO(2) level on retrobulbar hemodynamics and contrast sensitivity was investigated. METHODS: Thirty adults (age 31 +/- 7) were examined under normocapnic and hypercapnic conditions. Colour Doppler imaging was used to measure the velocity in the ophthalmic and central retinal artery. Moreover, contrast sensitivity using the CSV-1000 was investigated. Blood pressure, heart rate and intraocular pressure (IOP) were measured and ocular perfusion was calculated. RESULTS: Under hypercapnia, mean end tidal CO(2) increased from 36.4 mmHg to 42.5 mmHg and blood oxygen saturation increased from 98.3% to 98.6% (p < 0.0001). Hypercapnia significantly reduced IOP by 0.94 mmHg (p < 0.0008). In the central retinal artery, the mean PSV increased by 18% (p < 0.0001) and the mean EDV by 21% (p = 0.0054). In the ophthalmic artery, the mean PSV increased by 13% (p < 0.0001) and the mean EDV by 26% (p = 0.0002). Furthermore, there was a significant increase of contrast sensitivity (spatial frequency: 3cpd: p = 0.0016; 6cpd: p = 0.005; 12cpd: p = 0.0012). Systolic blood pressure (p = 0.0225), mean arterial blood pressure (p = 0.0097) and ocular perfusion pressure (p = 0.0013) increased significantly. CONCLUSION: This setting was able to detect an increase in blood flow velocity in normal subjects under hypercapnia. Furthermore, hypercapnia results in a functional improvement in contrast sensitivity, possible due to the increased blood flow or the increase in blood oxygen levels.

Fluorescein filling defects of the optic nerve head in normal tension glaucoma, primary open-angle glaucoma, ocular hypertension and healthy controls.

BACKGROUND: To evaluate fluorescein filling defects of the optic nerve head in normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), ocular hypertension (OHT) and controls. METHODS: Forty patients with NTG (mean age 55 +/- 10 years), 40 patients with POAG (mean age 55 +/- 11 years), 40 patients with OHT (mean age 53 +/- 13 years), and 40 age-matched controls (mean age 54 +/- 11 years) were included in a prospective study. Video fluorescein angiograms were performed by means of a scanning laser ophthalmoscope. The extent of absolute filling defects of the optic nerve head was assessed (as a percentage of the disc area) using digital image analysis. Visual fields were tested by automatic static perimetry (Humphrey Field Analyzer, programme 24-2). RESULTS: Absolute filling defects were significantly larger in patients with NTG (12.2 +/- 15.5%) and POAG (12.9 +/- 13.1%) compared to patients with OHT (1.2 +/- 3.6%) and healthy controls (0.1 +/- 0.5%) (p < 0.0001). The area under the receiver operating characteristic (ROC) curve was 0.806 for NTG vs healthy controls, and 0.812 for POAG vs OHT. Absolute filling defects are significantly correlated to the global indices mean deviation (r = -0.63, p < 0.0001), pattern standard deviation (r = 0.61, p < 0.0001), and corrected pattern standard deviation (r = 0.62, p < 0.0001) and significantly correlated to horizontal (r = 0.50, p < 0.0001) and vertical (r = 0.53, p < 0.0001) cup-to-disc-ratios. CONCLUSIONS: Fluorescein filling defects of the optic disc representing capillary dropout are present in NTG and POAG. The extent of these filling defects is correlated to visual field loss and morphological damage. Fluorescein angiography may be useful in the diagnosis and management of NTG and POAG.

Asymmetric visual field loss and retrobulbar haemodynamics in primary open-angle glaucoma.

PURPOSE: To investigate interocular differences in retrobulbar flow velocities in patients with asymmetric glaucomatous visual field loss. METHODS: Twenty-five patients with primary open-angle glaucoma (POAG) and asymmetric visual field loss were included in this study. Asymmetric visual field loss was defined as a difference of the global index mean deviation (MD) >6 dB between the two eyes. Flow velocities (peak systolic velocity PSV and end-diastolic velocity EDV) and resistive indices (RI) of the ophthalmic artery (OA), central retinal artery (CRA), and nasal and temporal posterior ciliary arteries were measured by means of colour Doppler imaging. RESULTS: MD of eyes with more severe glaucomatous visual field loss was -18.3+/-7.8 dB vs -6.8+/-5.5 dB (p<0.0001) in the less affected eyes. The PSV and the EDV of the CRA and the PSV of the OA were significantly decreased in eyes with more severe glaucomatous visual field loss (CRA PSV: 7.6+/-2.0 cm/s vs 8.3+/-1.7 cm/s, p=0.04; CRA EDV: 2.24+/-0.5 cm/s vs 2.55+/-0.6 cm/s, p<0.007; OA PSV: 29.7+/-9.9 cm/s vs 32.7+/-11.5 cm/s, p<0.02). None of the other differences in velocity or resistive index were significant. CONCLUSIONS: Patients with asymmetric glaucomatous visual field loss exhibit asymmetric flow velocities of the CRA and OA. Patients with more severe damage display reduced flow velocities in retrobulbar vessels in POAG.

Effect of different irrigating solutions on aqueous humour pH changes, intraocular pressure and histological findings after induced alkali burns.

PURPOSE: To evaluate the effects of hypo-osmolar tap water and isotonic saline solution on the intracameral pH, intraocular pressure and histological changes in alkali burned rabbit eyes. METHODS: Four groups of four rabbit corneas each were burned with 2 N sodium hydroxide, and then rinsed with 0.5 l or 1.5 l of saline solution or tap water, respectively. Changes in pH were monitored with an intracameral microelectrode. Intraocular pressure (IOP) was monitored by a transducer placed in the vitreous cavity. After enucleation, histology was performed. RESULTS: The pH increased after 1.5 min following alkali application. Irrigation with different solutions affected the maximum pH levels reached. Following the tap water rinse, the maximum rise was significantly lower than after the saline solution rinse. The maximum rise following rinsing with 1.5 l of tap water showed a significant delay. The increase in IOP was 23 +/- 10 mmHg without differences between the groups; the original pressure was recovered after 18 +/- 9 min. Histology of the eyes revealed a significant oedema in all corneas. Other ocular structures appeared unchanged. CONCLUSIONS: The hypo-osmolarity of tap water led to remarkable corneal oedema. Enlargement of the diffusion barrier and intracorneal dilution inhibit elevated intracameral pH levels. The difference in maximum pH levels reached may influence the degree of subsequent intraocular structure injury. Therefore, the use of iso-osmolar saline solution proves to be less efficacious than tap water as an irrigation agent for ocular burns.

Topical dorzolamide increases pericentral visual function in age-related maculopathy: pilot study findings with short-wavelength automated perimetry.

PURPOSE: Numerous studies have confirmed the enhancement of ocular circulation by carbonic anhydrase inhibitors (CAIs). Topical CAI treatment with dorzolamide averts the significant pericentral visual function loss accompanying retinal and choroidal vasoconstriction during acute hyperventilation-induced hypocapnia. This study was designed to discern whether dorzolamide might similarly enhance macular function in patients with age-related maculopathy (ARM). METHODS: In a masked, placebo-controlled study, 40 patients with ARM and acuity > 20/50 were randomized to receive either dorzolamide or placebo for 12 weeks, thrice daily. After pre-study perimetric training, pericentral function (mean sensitivity) was quantified using Humphrey 10-2 short-wavelength automated perimetry (SWAP), before and after 12 weeks of topical therapy. RESULTS: Dorzolamide-treated eyes demonstrated a significant increase in mean sensitivity of + 1.55 dB (p = 0.04); placebo-treated eyes showed no significant change (+ 0.58 dB; p = 0.10). Given the non-significant increase of mean sensitivity in the placebo-treated group, fewer than 100 subjects per group would be required to afford > 70% power to yield a significant direct comparative difference between treatment and placebo in a prospective, randomized study of equally short duration. CONCLUSIONS: This study demonstrated a significant increase in short-wavelength sensitivity in ARM with dorzolamide and the lack thereof with placebo. These encouraging pilot study data suggest a potential role for topical CAIs in ARM patients, and establish objective parameters for prospective studies to further evaluate the effects of dorzolamide in ARM.