Movement of retinal vessels toward the optic nerve head after increasing intraocular pressure in monkey eyes with experimental glaucoma.

A shift or displacement of the retinal blood vessels (RBVs) with neuroretinal rim thinning indicates the progression of glaucomatous optic neuropathy. In chronic open angle glaucoma, individuals with RBV positional shifts exhibit more rapid visual field loss than those without RBV shifts. The retinal vessels reportedly move onto the optic nerve head (ONH) in response to glaucoma damage, suggesting that RBVs are pulled toward the ONH in response to increased cupping. Whether this phenomenon only applies to RVBs located in the vicinity or inside the ONH or, more generally, to RBVs also located far from the ONH, however, is unclear. The aim of this study was to evaluate the movement of RBVs located relatively far from the ONH edge after increasing intraocular pressure (IOP) in an experimental monkey model of glaucoma. Fundus photographs were obtained in 17 monkeys. High IOP was induced in the monkeys by laser photocoagulation burns applied uniformly with 360° irradiation around the trabecular meshwork of the left eye. The right eye was left intact and used as a non-treated control. Considering the circadian rhythm of IOP, it was measured in both eyes of each animal at around the same time-points. Then, fundus photographs were obtained. Using Image J image analysis software, an examiner (N.E.) measured the fundus photographs at two time-points, i.e. before laser treatment (time 1) and the last fundus photography after IOP elevation (time 2). The following parameters were measured (in pixels): 1) vertical diameter of the ONH (DD), 2) distance from the ONH edge to the first bifurcation point of the superior branch of the central retinal vein (UV), 3) distance from the ONH edge to the first bifurcation point of the inferior branch of the central retinal vein (LV), 4) ONH area, and 5) surface area of the cup of the ONH. We calculated the ratios of UV to DD (UV/DD), LV to DD (LV/DD), and the cup area to disc area ratio (C/D). The mean UV/DD at time 1 (0.656 ± 0.233) was decreased at time 2 (0.542 ± 0.192) (p < 0.01), and the mean LV/DD at time 1 (0.642 ± 0.151) was decreased at time 2 (0.534 ± 0.171) (p < 0.01). The mean C/D at time 1 (0.303 ± 0.035) was increased at time 2 (0.556 ± 0.110) (p < 0.01). The mean IOP at time 1 was 19.8 ± 2.5 and that at time 2 was 54.2 ± 15.8. The amount and rate of the change in LV/DD and C/D between time 1 and time 2 were significantly correlated (r = -0.654 and -0.536, p = 0.004 and 0.026, respectively). Therefore, in an experimental monkey model of glaucoma, RBVs located relatively far from the ONH were pulled toward the ONH as cupping increased.

Changes in the thickness of the macular ganglion cell complex and retinal nerve fiber layer over time after surgery in a case of juvenile glaucoma.

PURPOSE: To report longitudinal changes over time after surgery in the topography of the optic disc, thickness of the circum papillary retinal nerve fiber layer (c-RNFL), and thickness of the macular ganglion cell complex (m-GCC) in a case of juvenile open angle glaucoma. OBSERVATIONS: Case report based on one patient. After significant edema of the optic disc for 2 months, the cup depth and cup volume measured by Heidelberg retina tomograph images showed reversal, which lasted for 3 years. The c-RNFL thickness and m-GCC thickness measured by spectral domain optical coherence tomography first increased for a week and then continued to decrease until 6 months after operation. These two parameters reached a plateau after 3 years. The mean deviation of global visual field indices of the Humphrey visual field revealed a very mild reduction for this 3 year period. CONCLUSIONS AND IMPORTANCE: In juvenile onset glaucoma, changes in c-RNFL thickness and m-GCC thickness after operation were not consistent with changes in optic disc cupping. Changes in the thicknesses of the c-RNFL or m-GCC, rather than changes in the optic disc changes, may be good surrogate measures to confirm the effectiveness of glaucoma surgery.

Optic disc and peripapillary morphology in unilateral nonarteritic anterior ischemic optic neuropathy and age- and refraction-matched normals.

PURPOSE: To compare optic disc morphologic features and peripapillary retinal nerve fiber layer (RNFL) thickness between the unaffected eyes of patients with unilateral nonarteritic anterior ischemic optic neuropathy (NAION) and their affected eyes and the eyes of age- and refraction-matched normal control subjects. DESIGN: Cross-sectional comparative study. PARTICIPANTS: Thirty-one patients with unilateral NAION and 62 age- and refraction-matched normal control subjects. METHODS: Optic disc morphologic features and peripapillary RNFL thickness were evaluated in both eyes of patients with unilateral NAION and in one randomly chosen eye of the normal control subjects. MAIN OUTCOME MEASURES: Optic disc and cup parameters were measured using the Heidelberg Retina Tomograph II (Heidelberg Engineering GmbH, Dossenheim, Germany), and RNFL thickness was measured by scanning laser polarimetry with variable corneal compensation (GDx VCC; Carl Zeiss Meditec, Dublin, CA). RESULTS: There was no significant difference in the disc area between the NAION affected eyes and the unaffected fellow eyes. The cup area, cup-to-disc area ratio, cup volume, and cup shape measure were greater, whereas the peripapillary RNFL thickness was smaller in the former than the latter (P = 0.001 to approximately 0.043). When the unaffected eyes of patients with NAION and the age- and refraction-matched normal control eyes were compared, the disc area, cup area, cup-to-disc area ratio, cup volume, mean cup depth, and cup shape measure were smaller in the former (P = 0.0006 to approximately 0.03); there was no significant difference in the RNFL thickness between the two (P>0.06). CONCLUSIONS: A comparison of the eyes with NAION and the fellow eyes indicated that the cup was slightly larger in the former than in the latter, suggesting the acquired enlargement of the cupping after NAION develops. A comparison of the unaffected fellow eyes in patients with NAION and the age- and refraction-matched normal control eyes suggested that a smaller disc area and smaller cupping were predisposing risk factors for the development of NAION.

Optic disc topography and peripapillary retinal nerve fiber layer thickness in nonarteritic ischemic optic neuropathy and open-angle glaucoma.

OBJECTIVE: To evaluate the results of scanning laser tomography and scanning laser polarimetry (SLP) and the correlations with visual field damage (VFD) in eyes with nonarteritic ischemic optic neuropathy (n-AION) compared with eyes with open-angle glaucoma (OAG). DESIGN: Cross-sectional study. PARTICIPANTS: Thirty-three eyes of 33 patients with n-AION and 33 eyes with OAG whose age and VFD evaluated with the Humphrey field analyzer were matched to those of the n-AION eyes. MAIN OUTCOME MEASURES: The parameters of optic disc topography obtained with the Heidelberg Retina Tomograph II (HRT II) and retinal nerve fiber layer (RNFL) thickness with GDx with variable corneal compensation and the correlation to VFD. RESULTS: The cup area, cup-to-disc area ratio, and mean cup depth were significantly smaller, and the cup shape measure more negative, in the n-AION eyes than in the OAG eyes (P<0.001), whereas rim area was significantly greater (P<0.001). Multivariate analyses showed that none of disc area, rim area, and mean cup depth in the n-AION eyes and only rim area (P = 0.029) in the OAG eyes was significantly associated with mean deviation (MD). Ellipse average of RNFL thickness significantly correlated with MD in the n-AION eyes (P = 0.045) and in the OAG eyes (P = 0.022). CONCLUSIONS: Disc topography of eyes with n-AION was quantitatively characterized by small and shallow cupping and a relatively large rim area compared to eyes with OAG matched for age and VFD. In eyes with n-AION, significant correlation with VFD was found only for the RNFL thickness evaluated with SLP but not for the HRT II parameters.

Frequency doubling technology and scanning laser tomography in eyes with generalized enlargement of optic disc cupping.

PURPOSE: To characterize functional and structural changes in eyes with generalized enlargement of optic disc cupping (vertical cup/disc ratio > or = 0.8), normal intraocular pressure, normal standard achromatic automated perimetry (SAP) results, and no other ophthalmoscopic findings suggesting glaucoma (large C/D eyes) using frequency doubling technology (FDT) and the Heidelberg Retina Tomograph (HRT). METHODS: This comparative observational case series included 30 large C/D eyes (30 subjects), 17 eyes (17 patients) with early-stage normal tension glaucoma with generalized enlargement of optic disc cupping (NTG eyes), and 25 eyes from 25 normal subjects (normal eyes). Results with Humphrey 30-2, FDT N-30 threshold programs, and HRT were compared among these groups. Large C/D eyes were subdivided into FDT-normal and -abnormal eyes according to the predetermined criteria and HRT parameters were compared among them. RESULTS: No significant difference was seen in HRT parameters between the large C/D and NTG eyes. In the large C/D eyes, FDT mean deviation was lower than in the normal eyes and higher than in the NTG eyes, whereas FDT pattern standard deviation was smaller than in the NTG eyes (P = 0.02-0.03). Among HRT parameters, only cup shape measure (CSM) showed significant negative correlation with FDT mean deviation in the large C/D eyes. Between FDT-normal and -abnormal subgroups, only CSM showed significant difference (P < 0.01). CONCLUSION: Frequency doubling technology showed abnormalities in large C/D eyes. Only CSM showed significant correlation with FDT result and difference between those with normal and abnormal FDT results. In management of large C/D eyes, FDT and CSM will be useful to detect functional and structural change.

[The effect of phosphodiesterase type 3 inhibitor on chorio-retinal blood flow in rabbits eyes].

PURPOSE: To investigate the ocular effect of intravenous administration of a phosphodiesterase type 3 inhibitor (NSP-805) and to compare the effect of NSP-805 with that of a calcium antagonist (nicardipine hydrochloride) on chorio-retinal blood flow in anesthetized albino rabbits. METHODS: Twenty-four female albino rabbits (weighting 2.0-4.0 kg) were anesthetized with intravenous injection. NSP-805(40 micrograms/kg and 100 micrograms/kg) and nicardipine of 40 micrograms/kg were intravenously administrated to the anesthetized rabbits. Intravenously administration of 20% dimethyl sulfoxide (DMSO) was used as a vehicle. Chorio-retinal blood flow was measured with a laser Doppler flowmeter at baseline and every 20 minutes after intravenous administration for 120 minutes. Heart rates and systemic blood pressure were monitored. Baseline measurements were compared with every 10 minutes after intravenous administration. Differences between the drug groups and vehicle group were analyzed. RESULTS: After administration of a low dose of NSP--805 (40 micrograms/kg) and nicardipine (40 micrograms/kg), the chorio-retinal blood flow was significantly increased (p < 0.05). A high dose NSP-805(100 micrograms/kg) reduced systemic blood pressure significantly, but the increase of chorio-retinal blood flow was less than that at the low dose of NSP-805(40 micrograms/kg) and nicardipine (40 micrograms/kg). Chorio-retinal blood flow in the NSP 805(40 micrograms/kg) and nicardipine (40 micrograms/kg) groups was significantly increased over that in the control group (20% DMSO) (p < 0.05). CONCLUSION: The results suggest that the NSP-805 has the potential of increasing chorio-retinal blood flow in rabbit eyes.