Etsuo Chihara

Severe Myopia as a Risk Factor for Progressive Visual Field Loss in Primary Open-Angle Glaucoma

The optic nerve head in severely myopic eyes may be particularly vulnerable to glaucomatous damage. To study this hypothesis, we examined 122 primary open-angle glaucoma eyes with fair to good control of the intraocular pressure and a sign of baseline optic nerve damage. Then, parameters for the progression of the visual field defects were evaluated by multivariate analysis. A high mean intraocular pressure (p = 0.007) and a large refractive error (p = 0.023) were significant risk factors for subsequent visual field loss. A high baseline cup-to-disk ratio (p = 0.100) was a marginal risk factor. Nonsignificant parameters included patient age (p = 0.692), the use of beta-adrenergic antagonists (p = 0.384), gender (p = 0.831) and left versus right side (p = 0.977). When the refractive error was used to subclassify patients into severely myopic (< or = -4 dpt), mildly myopic (-0.25 to -4 dpt), or emmetropic and hyperopic (> or = 0 dpt), only severe myopia was a significant risk factor for progressive visual field loss. Severe myopia, but not mild myopia, is a significant risk factor for subsequent visual field loss in patients with primary open-angle glaucoma.

Retinal Nerve Fiber Layer Defect as an Early Manifestation of Diabetic Retinopathy

PURPOSE An incidence of and risk factors for retinal nerve fiber layer defect were investigated in patients with type II diabetes mellitus and compared with that of age-matched control subjects. METHODS The authors photographed the retinal nerve fiber layer of the right eye in each of 137 patients with diabetes and 144 healthy control subjects. The level of diabetic retinopathy ranged from levels 1 (no microaneurysm) to 4 (eyes with localized intra-retinal microvascular abnormalities or venous beading). Risk factors for the nerve fiber layer defect analyzed were age of patients, visual acuity, axial length, optic disc size, glycosylated hemoglobin, systolic blood pressure, and level of diabetic retinopathy. RESULTS Defects of the retinal nerve fiber layer were found in 6/30 (20%) eyes with level 1 retinopathy, 8/14 (57%) eyes with level 2 retinopathy, 24/47 (51%) eyes with level 3 retinopathy, and 36/46 (78%) eyes with level 4 retinopathy. These defect incidences were significantly higher than that of the control group, which had 5/144 (3.5%) defects (P < or = 0.001). Risk factors for this nerve defect were level of diabetic retinopathy (P = 0.002), high systolic blood pressure (P = 0.0232), and patients age (P = 0.0478). Not correlated with the incidence of the retinal nerve fiber layer defect were visual acuity, disc size, axial length, and glycosylated hemoglobin level at the time of examination. CONCLUSION These findings suggest that the retinal nerve fiber layer defect is common in patients with early diabetic retinopathy. Risk factors for this defect were higher level of diabetic retinopathy, systemic hypertension, and advanced age.

Comparison of surgical outcomes of combined viscocanalostomy and cataract surgery with combined trabeculotomy and cataract surgery

PURPOSE To compare the outcomes of combined viscocanalostomy, phacoemulsification, and intraocular lens (IOL) implantation with combined trabeculotomy, phacoemulsification, and IOL implantation in patients with primary open-angle glaucoma (POAG). DESIGN Nonrandomized clinical trial. METHODS Fifty-seven eyes (57 POAG patients) that underwent viscocanalostomy, phacoemulsification, and intraocular lens (IOL) implantation between March 2000 and April 2001 and were followed for over 6 months postoperatively comprised the viscocanalostomy (VCS) group. Fifty-seven of 105 eyes (105 POAG patients) that underwent trabeculotomy, phacoemulsification, and IOL implantation between April 1995 and February 2000 and were followed for over 6 months and < 2 years comprised the trabeculotomy (LOT) group. The reductions of postoperative intraocular pressure (IOP) and antiglaucoma medication use in both groups were compared. Best-corrected visual acuity (VA) and complication rates were secondary outcomes. The success probabilities related to postoperative IOP level in both groups were evaluated by Kaplan-Meier life-table analysis with log-rank test. RESULTS Significant reductions of IOP and antiglaucoma medication use occurred in both groups up to 1 year postoperatively, but were not significantly different between the two groups. The success probabilities of the VCS group for IOP control under 21, 17, and 15 mm Hg were 95%, 74%, and 44%, respectively, at 6 months, 95%, 67%, and 32% at 1 year, and not significantly different from the LOT group. All eyes in the VCS group had VA equal to or better than baseline 3 months postoperatively. The incidences of postoperative fibrin reaction (14 eyes, 25%) and microperforations of the Descemet membrane (14 eyes, 25%) in the VCS group were higher than in the LOT group (P =.0004 and P <.0001, respectively). CONCLUSIONS Intraocular pressure reduction and VA improvement after the two procedures were similar in Japanese patients with POAG and cataract.

Surgical outcome of combined trabeculotomy and cataract surgery.

PurposeTo evaluate the efficacy of combined trabeculotomy and cataract surgery in lowering intraocular pressure and improving visual acuity in adults with primary open-angle glaucoma. Patients and MethodsA consecutive series of 141 eyes with primary open-angle glaucoma or ocular hypertension was prospectively recruited. One hundred five eyes with visual field defects were treated by trabeculotomy combined with phacoemulsification and intraocular lens implantation (TPI group), and 36 eyes without visual field defects underwent cataract surgery (PI group). Patients in the TPI and PI groups were followed for more than 6 months after surgery (578.1 ± 35.8 days and 616.0 ± 58.5 days, respectively). The intraocular pressure reductions after surgery were compared between the groups to evaluate the effect of combined trabeculotomy and cataract surgery. Visual acuity and the complication rate in the two groups were secondary outcomes. The success probabilities of both groups were evaluated by Kaplan–Meier life table analysis with log rank test. ResultsA significant intraocular pressure reduction was observed in the TPI and PI groups up to 3 years and up to 1 year and 6 months after surgery, respectively; the magnitude of the reduction was significantly larger in the TPI group up to 3 years after surgery. The success probabilities of TPI group for intraocular pressure control under 21, 17, and 15 mm Hg were 95.8%, 58.7%, and 30.0%, respectively, 1 year after surgery, and 84.9%, 29.5%, and 13.5%, respectively, 3 years after surgery; the success probabilities were significantly higher than those of the PI group. Of 105 eyes, 104 (99.0%) had visual acuity equal to or better than the baseline acuity 3 months after combined trabeculotomy and cataract surgery. ConclusionCombined trabeculotomy and cataract surgery normalizes intraocular pressure and improves visual acuity in adults with glaucoma and coexisting cataract.

Impact of high myopia on the performance of SD-OCT parameters to detect glaucoma

BackgroundThe aim was to evaluate the effects of high myopia on spectral-domain optical coherence tomography (SD-OCT) parameters, as well as on their ability to detect glaucoma.MethodsNinety-three glaucoma and 86 non-glaucoma patients were divided into highly myopic group (HMG; 90 subjects, ≤ −5 diopters [D]) and emmetropic (EG; 89 subjects, spherical equivalent ≤1 D and ≥ −1D) groups in this cross-sectional comparative study. Macular ganglion cell complex (GCC) and circumpapillary retinal nerve fiber layer (cpRNFL) measurements obtained from the algorithms of the SD-OCT system were compared. The effects of refractive errors and glaucoma were assessed using a generalized linear model, after adjusting for age. A receiver operating characteristic curve was constructed for each parameter, and the areas under the curves (AUCs) were compared.ResultsThe all cpRNFL measurements were significantly related to both refractive errors and glaucoma, while all GCC parameters were not significantly related to the refractive errors. The AUC for average GCC thickness was similar between the HMG (AUC, 0.935) and EG (AUC, 0.933), while the AUC for average cpRNFL thickness differed significantly (p = 0.028) between the HMG (AUC, 0.827) and EG (AUC, 0.939).ConclusionsMacular GCC parameters showed good ability to detect glaucoma in both groups, whereas the ability of cpRNFL measurement in HMG subjects was inferior to that in EG subjects. Assessment of GCC parameters is a useful technique complementary to cpRNFL thickness assessment, for clinically evaluating patients with concomitant glaucoma and high myopia.

Quantitative Retinal Optical Coherence Tomography Angiography in Patients With Diabetes Without Diabetic Retinopathy

Purpose To compare optical coherence tomography (OCT) angiographic parameters in retina and choriocapillaris between control subjects and diabetic patients without diabetic retinopathy (NDR). Correlations were studied between OCT angiography parameters, retinal structure parameters, and systemic characteristics in all subjects. Methods Sixty-two patients were included in the study: control subjects (n = 33) and patients with NDR (n = 29). Optical coherence topography angiographic parameters were as follows: vessel density (%) (in superficial, deep retinal vessel plexus and in choriocapillary layer) and foveal avascular zone (FAZ) area (mm2) in superficial and deep retinal vessel plexus of parafovea. Split-spectrum amplitude decorrelation angiography (SSADA) software algorithm was used for evaluation of vessel density and FAZ area (nonflow area tool). Spectral-domain OCT was used to assess full, inner, and outer retinal thickness and volume in parafovea. Results In superficial and deep retina, vessel densities in NDR (44.35% ± 13.31% and 31.03% ± 16.33%) were decreased as compared to control subjects (51.39% ± 13.05%, P = 0.04; and 41.53% ± 14.08%, P < 0.01). Foveal avascular zone in superficial retina of NDR patients (0.37 ± 0.11 mm2) was greater than in controls (0.31 ± 0.10 mm2, P = 0.02). Superficial vessel density significantly correlated with full retinal thickness and volume in parafovea (r = 0.43, P = 0.01; r = 0.43, P = 0.01) and with outer retinal volume in parafovea (r = 0.35, P < 0.05) of healthy subjects. Systolic blood pressure and ocular perfusion pressure significantly correlated with deep vessel density in NDR (r = -0.45, P = 0.02; r = -0.46, P = 0.01), but not in controls. Conclusions Superficial and deep retinal vessel density in parafovea of diabetic patients without diabetic retinopathy are both decreased compared to healthy subjects. The associations between vessel density with retinal tissue thickness and with subjects clinical characteristics differ between healthy subjects and patients with NDR.

Parameters associated with papillomacular bundle defects in glaucoma

AbstractTo evaluate the relationship between the papillomacular bundle defect and glaucoma types, abnormalities of the optic disc, distance between the disc and foveola, and axial length, we examined one eye of 82 patients with normal tension glaucoma, 117 patients with chronic high tension glaucoma, and 102 controls. Two types (diffuse and focal types) were found in the papillomacular bundle defect, and the former predominated. Eyes with a long axial length (P<0.01), a diagnosis of normal tension glaucoma (P < 0.05), or a large optic disc (P<0.05) tended to have diffuse-type papillomacular bundle defects, while eyes with a short axial length, a diagnosis of high tension glaucoma, or a large ovalness index are less likely to have it. Thus, a long axial length, a large optic disc, and normal tension glaucoma are risk factors for the diffuse-type papillomacular bundle defect. Correspondence to: E. Chihara

Effects of tranilast on filtering blebs: a pilot study.

PurposeTo investigate the effects of topical instillation of 0.5% tranilast eye drops on intraocular pressure (IOP) and bleb formation after glaucoma filtering surgery. Patients and MethodsThis was a prospective, randomized, double-masked, and controlled clinical trial. A total of 52 eyes of 52 patients were randomly assigned to receive either 0.5% tranilast eye drops (24 eyes) or vehicle saline solution (28 eyes) 4 times daily for 3 months after trabeculectomy. Features of the bleb, such as vascularization and size, and intraocular pressure were studied. ResultsThe incidence of vascularized bleb and “pseudopod” formation 6 months post treatment were more common in tranilast-treated eyes than control eyes (P = 0.019 and P = 0.043, respectively). The bleb was significantly larger at 6 and 12 months (P = 0.024 and P = 0.049, respectively), and reduction of the IOP was more significant for 2 years postoperatively (P = 0.002 to P = 0.032) in tranilast-treated eyes than control eyes. No vision-threatening side reactions were associated with tranilast. ConclusionsThe use of topical tranilast after filtering surgery alleviates ischemia of the filtering bleb, reduces IOP, and increases the size of the bleb.

Covariation of optic disc measurements and ocular parameters in the healthy eye

To understand the variations in optic disc topography that may affect the local susceptibility of nerve fibers to glaucomatous damage, we evaluated the correlations between optic disc topography and selected ocular parameters in 210 normal eyes of healthy Japanese. In the total study group, eyes with a longer axial length had a longer distance between the disc and foveola, a larger index of ovalness and a larger disc (P < 0.01). A longer disc-foveola distance correlated with a larger index of ovalness (P<0.01). The optic discs of severely myopic eyes had a considerably different structure from other eyes. Eyes with a tilted optic disc were unique in that the area of the optic disc was not large despite a positive correlation with long axial length (P<0.01) a long disc foveola distance (P<0.01), and a large index of ovalness (P<0.01). Eyes with a rotated optic disc were another special case. This eye type correlated in a contradictory fashion with two parameters: a large axial length (P<0.01) and a short disc-foveola distance (P<0.01). These findings suggest that changes in optic disc topography or susceptibility to glaucomatous damage correlate with selected ocular parameters but are not completely parallel.

A 3-Year Follow-Up Study of Ocular Hypertension by Pattern Electroretinogram

A 3-year following-up study of the pattern electroretinogram (PERG) was performed in 15 eyes of 8 ocular hypertensive (OHT) patients. At first PERG recording, the amplitude of the first positive wave P1 was statistically significantly reduced in the OHT patients compared with age-matched controls (p < 0.05). There was no difference in the amplitude of the second negative wave N2 (p > 0.05). At 40 months, the amplitude of both P1 and N2 decreased and the latency of P1 was elongated. Among the changes, the decrease in N2 amplitude was the most drastic (p = 0.0001 compared with the control, p < 0.05, compared with the first recording). Glaucomatous visual field defects developed 5 years after the first PERG recording and 2 years after the reduction in N2 amplitude in 1 patient. Decreased N2 amplitude of the PERG may be an important warning sign predicting the development of glaucoma in OHT patients.