Long-term efficacy and safety of ranibizumab administered pro re nata in Japanese patients with neovascular age-related macular degeneration in the EXTEND-I study

PURPOSE

To evaluate the long-term efficacy and safety of ranibizumab administered pro re nata (PRN) in Japanese patients with choroidal neovascularization secondary to age-related macular degeneration during the extension phase of the EXTEND-I study.

METHODS

EXTEND-I, an open-label, multicenter, Phase I ⁄ II study comprised: a single-injection (Group A); a multiple-injection (Groups A and B; the latter consisted of patients who did not participate in the single-injection phase); and an extension phase. In the extension phase, a PRN regimen of ranibizumab (0.3 or 0.5 mg) guided by monthly best-corrected visual acuity (BCVA) score and other ophthalmic examinations was employed. The efficacy variables included the mean BCVA change from Month 12 to the last visit in Group B. Safety was assessed in all patients.

RESULTS

In the extension phase, efficacy was assessed only in Group B patients. The number of ranibizumab injections per year in the 0.3 and 0.5 mg Group B patients was 4.19 and 4.27, respectively. The mean BCVA change (SD) from Month 12 to the last visit was )3.6 (14.82) letters for 0.3 mg (n = 28) and )2.2 (7.92) letters for 0.5 mg groups (n = 33) in Group B. Conjunctival haemorrhage and nasopharyngitis were the most commonly reported adverse events. Of the 13 serious adverse events reported, cerebral infarction (two incidences) was suspected to be study-drug related.

CONCLUSIONS

Pro re nata regimen of ranibizumab guided by monthly BCVA and other ophthalmic examinations appears effective in sustaining the BCVA gained with 12 monthly injections while reducing the number of injections during the extension phase. Ranibizumab was well tolerated during the extension phase.

Activated protein C rescues the retina from ischemia-induced cell death

PURPOSE

Ischemia causes severe and persistent visual loss in many eye diseases, including central retinal vein occlusion (CRVO) and diabetic retinopathy. Activated protein C (APC) has been demonstrated to reduce the cell death associated with ischemia in the brain and kidney. This study was performed to examine the ability of APC to rescue hypoxia-induced retinal cell death in vitro and in vivo.

METHODS

Retinal pigment epithelium (RPE) and photoreceptor cells were placed in either a normoxic or a hypoxic chamber. Immediately before they were subjected to ischemia, the cultures were treated with APC (3-240 μg/mL). Incubation was followed by an MTT assay to determine the number of viable cells. The activity of caspase-3, -8, and -9 in RPE cells was also analyzed. Various concentrations of APC were intravitreally injected in a rat CRVO model, followed by TUNEL staining to detect the in vivo effects of APC.

RESULTS

Lower concentrations of APC (0.3-30 μg/mL) showed a cell-protective effect against hypoxia in vitro, whereas higher concentrations (≥120 μg/mL) demonstrated cytotoxicity in both RPE and photoreceptor cells. Caspase-3, -8, and -9 were activated when the cells were exposed to hypoxia, but this activation was significantly inhibited by APC. Experimental CRVO-induced retinal cell apoptosis was reduced dramatically by intravitreal injection of APC.

CONCLUSIONS

APC can reduce ischemia-induced cytotoxicity both in vitro and in vivo via blocking the activation of caspase-3, -8, and -9. APC may be a promising candidate for protecting the retina from ischemia.

Simultaneous intravitreal injection of triamcinolone acetonide and tissue plasminogen activator for central retinal vein occlusion: a pilot study

PURPOSE

To evaluate the efficacy and safety of simultaneous intravitreal injection of triamcinolone acetonide (TA) and tissue plasminogen activator (tPA) for macular oedema associated with central retinal vein occlusion (CRVO).

METHODS

Twenty eyes of 20 patients with CRVO were enrolled. A mixture of TA (4 mg) and tPA (25 μg) was injected into the vitreous of 20 eyes with CRVO. Best corrected visual acuity (BCVA) and macular thickness before and 1, 3, 6 and 12 months after the procedure were measured.

RESULTS

The BCVA improved three lines or more in 65%, 55%, 55% and 53% of eyes and the mean macular thickness decreased from 1072 μm to 455, 450, 480 and 409 μm (p<0.001) at 1, 3, 6 and 12 months, respectively. Fifteen (75%) of the 20 eyes required at least one additional injection to prevent a recurrence of macular oedema. The intraocular pressure increased in four eyes.

CONCLUSION

Overall, intravitreal injection of the TA/tPA mixture improved the BCVA by three lines or more in at least 50% of eyes and decreased the mean macular thickness at four time points without serious side effects. A randomised clinical trial is necessary to evaluate the efficacy of this treatment.

EXTEND-I: safety and efficacy of ranibizumab in Japanese patients with subfoveal choroidal neovascularization secondary to age-related macular degeneration

PURPOSE

To evaluate the efficacy and safety of intravitreal ranibizumab for subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) in Japanese patients.

METHODS

This open-label, multicentre, Phase I/II study enroled patients into Group A (single injection of ranibizumab nonrandomized doses of 0.3 or 0.5 mg followed by 11 monthly injections of the same dose) and Group B (12 monthly injections of ranibizumab randomized to 0.3 or 0.5 mg). The primary efficacy endpoint was the mean change from baseline in best-corrected visual acuity (BCVA) score at Month 6. Safety was evaluated in all patients who received ranibizumab.

RESULTS

Of 88 patients enroled, 12 entered Group A (six per dose) and 76 entered Group B (0.3 mg: n = 35; 0.5 mg: n = 41). Mean change from baseline in BCVA was significantly increased for both doses (Group B) at Month 6 (0.3 mg: +8.1 letters, p = 0.0006; 0.5 mg: +9.0 letters, p < 0.0001) and Month 12 (0.3 mg: +9.5 letters, p = 0.0001; 0.5 mg: +10.5 letters, p < 0.0001). At Month 12, one patient (0.3 mg) and 0 patients (0.5 mg) lost > or =15 letters, while 37.1% (0.3 mg) and 31.7% (0.5 mg) of patients gained > or =15 letters. Ocular serious adverse events (SAEs) of the study eye were reported in 1 and 2 patients in the 0.3- and 0.5-mg groups, respectively. Nonocular SAEs were experienced by 2 and 5 patients in the 0.3- and 0.5-mg groups, respectively. No cases of endophthalmitis were reported.

CONCLUSION

Ranibizumab was effective and well tolerated in Japanese patients with subfoveal CNV secondary to AMD.

Ocular risk factors for choroidal neovascularization in pathologic myopia

PURPOSE. To identify the risk factors for development of myopic choroidal neovascularization (mCNV), a major cause of visual impairment. METHODS. Enrolled in the study were 23 consecutive patients with bilateral high myopia (axial length, > or =26.5 mm or refractive error, < or =8 D) and unilateral newly developed mCNV who presented to the Myopia Clinic, Osaka University Hospital. Spectral-domain optical coherence tomography (SD-OCT) showed that the fellow eyes had a normal macula. The parameters in the affected and fellow eyes were compared between the individual patients, including best-corrected visual acuity (BCVA), intraocular pressure (IOP), refractive error, axial length, choroidal thickness (CT) (subfoveal, 1.5 mm superiorly and inferiorly), posterior staphyloma height 3 mm from the fovea, length of retinal pigment epithelium (RPE) curvature within 6 mm measured on SD-OCT images, and choroidal degeneration and lacquer crack formation, graded according to a published

METHOD

RESULTS. The IOP, axial length, refractive error, and chorioretinal degeneration did not differ significantly. Affected eyes had a significantly higher lacquer crack grade (P < 0.05). The superior CT was not significantly different; the subfoveal and inferior CTs were significantly lower in the affected eyes (P < 0.05 and P < 0.001, respectively). The absolute value of the nasal posterior staphyloma height from the fovea was significantly greater in the affected eyes (P < 0.05), and the affected eyes had a significantly (P < 0.05) longer RPE curvature. CONCLUSIONS. Choroidal thinning resulting from increased RPE/choroid curvature is a risk factor for unilateral mCNV.

Prevalence and features of keratitis with quantitative polymerase chain reaction positive for cytomegalovirus

PURPOSE

To assess corneal scrapings and aqueous humor samples analyzed by polymerase chain reaction (PCR) that were positive for cytomegalovirus (CMV) in patients with keratitis of unknown origin and to investigate their clinical manifestations.

DESIGN

Retrospective, interventional case series.

PARTICIPANTS

Seventy-eight patients with epithelial (n=37), stromal (n=12), or endothelial keratitis (n=29) of unknown origin examined at the Osaka University Medical Hospital.

METHODS

Clinical examination and tears, corneal scrapings, and aqueous humor specimens were evaluated by real-time PCR for CMV.

MAIN OUTCOME MEASURES

Quantification of CMV DNA at the diagnosis of each type of keratitis with unknown origin and monitoring during the therapeutic course for CMV-positive cases.

RESULTS

No cases of epithelial or stromal keratitis had CMV DNA. Seven of 29 corneal endotheliitis cases (24.1%) were positive for CMV. Cytomegalovirus-positive cases of corneal endotheliitis characterized by localized corneal edema and keratic precipitates included 4 patients who had undergone penetrating keratoplasty and were refractory to the treatment for graft rejection and 3 patients with idiopathic endotheliitis. Cytomegalovirus DNA copy numbers were estimated and ranged from 6.3x10(4) to 3.6x10(6)/ml. In all positive cases, the numbers of CMV DNA copies decreased within weeks during treatment with systemic and topical ganciclovir (GCV) combined with a topical steroid. Five eyes (62.5%) had clinical improvement. In cases of endothelial keratitis, diabetes mellitus was significantly higher in patients positive for CMV (71.4%) than in patients negative for CMV (18.2%, P=0.016, chi-square test).

CONCLUSIONS

A total of 24.1% of cases with corneal edema of unknown origin were CMV positive and should be included in the differential diagnosis of idiopathic corneal endotheliitis or graft edema after penetrating keratoplasty, especially for bullous keratopathy. Real-time PCR for CMV, based on the diagnosis and monitoring of the clinical course, may be useful. Cytomegalovirus corneal endotheliitis requires early appropriate treatment using GCV. Because clinical remission after GCV may depend on the area of normal endothelium, early diagnosis and therapy are important for CMV corneal endotheliitis.

Efficacy of suprachoroidal-transretinal stimulation in a rabbit model of retinal degeneration

Purpose. To develop a middle-sized animal model of outer retinal degeneration and to evaluate the effectiveness of suprachoroidal-transretinal stimulation (STS) in eliciting cortical potentials from this model. Methods. Twelve rabbits were intravenously injected with 0.47 mg/kg verteporfin and the retinas were irradiated with a red light for 90 minutes. Fluorescein angiography and full-field and focal electroretinography (ERG) were performed at 7 and 28 days after the irradiation. Electrically evoked potentials (EEPs) were elicited by electrical stimulation, with the STS electrode implanted over the irradiated region, 1 month and 1 year after the irradiation. EEPs were also recorded from three rabbits before and after retinotomy of the normal retina surrounding the degenerated area, to eliminate the influence of stray currents. The retina beneath the site of the STS electrode was examined histologically at 1 month (group 1) and 1 year (group 2) after the irradiation. Results. An extensive area of degeneration was detected histologically, mainly in the outer retina after the irradiation. Focal ERGs were not recorded when the stimulus was confined to the irradiated area; however, EEPs were successfully elicited by STS of the same area 1 month and 1 year after the irradiation. The 360 degrees retinectomy did not significantly alter the amplitudes, the implicit times, or the thresholds of EEPs evoked by STS. Conclusions. Verteporfin with light irradiation induces degeneration predominantly in the outer retinal layers in rabbits. The elicitation of EEPs by STS from the degenerated area suggests that the STS system may be useful in patients with retinitis pigmentosa.

Long-term results of intravitreal bevacizumab injection for choroidal neovascularization secondary to angioid streaks

PURPOSE

To investigate the long-term efficacy of intravitreal injections of bevacizumab (Avastin; Genentech Inc, South San Francisco, California, USA) for choroidal neovascularization (CNV) secondary to angioid streaks.

DESIGN

Observational case series.

METHODS

Fifteen eyes of 13 patients (5 men, 8 women; mean age, 59 years; range, 54 to 70 years) treated with 1-mg intravitreal bevacizumab injections were included. The minimum follow-up after the first injection was 12 months. Eyes that had undergone previous treatments were excluded. The best-corrected visual acuity (BCVA) was measured. Optical coherence tomography and fluorescein angiography images were examined before and after treatment.

RESULTS

The mean follow-up was 19 months (range, 12 to 24 months). The mean number of injections for primary CNV was 4.5 (range, 1 to 9). The mean preoperative BCVA (decimal equivalent) was 0.39 (range, 0.08 to 1.5) and 0.47 (range, 0.06 to 1.2) at the final visit (P = .355). The BCVA improved by 2 lines of logarithm of the minimum angle of resolution visual acuity at the final visit in 5 eyes (33%), was unchanged in 8 eyes (54%), and decreased in 2 eyes (13%). The final fluorescein angiography examination showed no leakage in 10 eyes (67%), minimal leakage in 2 eyes (13%), and persistent or recurrent leakage in 3 eyes (20%). Five eyes (33%) had a recurrence 4 to 7 months (mean, 5.1 months) after the last bevacizumab injection. New CNV lesions developed in different areas in 3 eyes (20%) 6 to 14 months after the last bevacizumab injection for primary CNV.

CONCLUSIONS

An intravitreal injection of bevacizumab seems to maintain visual acuity. However, CNV frequently recurred or new CNV developed during the long follow-up.

Intravitreal bevacizumab vs sub-tenon triamcinolone acetonide for choroidal neovascularization attributable to pathologic myopia

PURPOSE

To compare the visual outcomes of intravitreal bevacizumab (Avastin; Genentech Inc, South San Franciso, California, USA) and sub-Tenon triamcinolone acetonide (TA) for choroidal neovascularization attributable to pathologic myopia (mCNV).

DESIGN

Retrospective, comparative, interventional case series.

METHODS

Fifty-four consecutive eyes of 53 patients with mCNV treated with either sub-Tenon TA or intravitreal bevacizumab in an institutional setting were included. Twenty eyes were treated with sub-Tenon TA and 34 eyes were treated with intravitreal bevacizumab. The main outcome measures included best-corrected visual acuity (BCVA) 12 months after the initial injection and logarithm of the minimum angle of resolution gain from baseline compared with analysis of covariance (ANCOVA).

RESULTS

At 12 months, the BCVA improved by 1.9 lines in the intravitreal bevacizumab group and worsened by 0.3 lines in the sub-Tenon TA group. Thus, the intravitreal bevacizumab group had significantly greater visual improvement than the sub-Tenon TA group (P < .01). Statistical analysis (ANCOVA) revealed that age (P = .01), pretreatment BCVA (P < .01), and the treatment choice (intravitreal bevacizumab or sub-Tenon TA; P < .01) correlated significantly with the BCVA and the BCVA gain at 12 months. The refractive error was of borderline significance (P = .06).

CONCLUSIONS

Although this study is limited because of its retrospective nature, intravitreal bevacizumab seems to result in a more favorable visual outcome than sub-Tenon TA in the treatment of mCNV. Patient age, the BCVA before treatment, and the refractive error must be considered to initiate the treatment.

Effects of Kallidinogenase on Ischemic Changes Induced by Repeated Intravitreal Injections of Endothelin-1 in Rabbit Retina

PURPOSE

Repeated intravitreal injections of endothelin-1 (ET-1) lead to alterations in the visually evoked potentials (VEPs) and loss of retinal ganglion cells (RGCs) in rabbits. The purpose of this study was to determine whether kallidinogenase can offset the alterations induced by ET-1.

METHODS

ET-1 (2.5 x 10(-7) M, 20 microL) was injected into the vitreous of the right eye of rabbits (ET-1-treated eyes, n = 30) twice a week for 4 weeks. The vehicle for ET-1 was injected into the left eye on the same schedule (vehicle treated eyes, n = 30). During this 4 weeks period, kallidinogenase (1.0 unit/kg/day, kallidinogenase-treated group) or saline (saline-injected control group) was continuously delivered intravenously by an implanted osmotic pump. VEPs were recorded before, and 2 weeks and 4 weeks after, the first ET-1 injection, and all rabbits were sacrificed at 4 weeks. The number of RGC cells was counted in hematoxylin- and eosin-stained retinal sections. In the analyses, the ET-1 induced alterations were normalized to the values in the vehicle treated control eyes, i.e., kallidinogenase (K) + ET-1/K+ vehicle or saline (S) +ET-1/S + vehicle. Retinal sections were also examined by immunohistochemistry with antibodies to single-stranded DNA (ssDNA) or to glial fibrillary acidic protein (GFAP). The effect of kallidinogenase on the ONH blood flow was determined by a hydrogen gas clearance flowmeter.

RESULTS

The significant prolongation of the relative VEP implicit times (ITs) 4 weeks after the ET-1 injection (P < 0.01, paired t test; post-ET-1 vs. pre-ET-1) was significantly decreased by kallidinogenase (P < 0.001, t test, K + ET-1/K+ vehicle vs. S +ET-1/S + vehicle). The relative number of RGCs was decreased in the saline-injected group, and this decrease was also decreased by kallidinogenase (P < 0.05, t test, K + ET-1/K+ vehicle vs. S +ET-1/S + vehicle). ssDNA staining showed fewer apoptotic cells in the retina of kallidinogenase-treated rabbits. Intravitreal injection of ET-1 also decreased the blood flow in the optic nerve head and increased the GFAP immunostaining and axonal degeneration. These changes were also counteracted by kallidinogenase.

CONCLUSION

These results indicate that kallidinogenase can counter the effects of ET-1 and should be considered for the treatment of ischemic retinal and optic nerve disorders related to abnormal ET-1 production.

Imaging of titanium:sapphire laser retinal injury by adaptive optics fundus imaging and Fourier-domain optical coherence tomography

PURPOSE

To examine and observe the subtle retinal injuries caused by a titanium:sapphire laser with a high-resolution adaptive optics (AO) fundus camera and with Fourier-domain optical coherence tomography (FD-OCT).

DESIGN

Observational case series.

METHODS

Four eyes of 2 individuals who experienced an accidental exposure to reflected light from a titanium:sapphire laser were examined. High-resolution retinal images were obtained with the AO fundus camera and by FD-OCT, and the images were compared with the findings obtained by standard clinical tests, including the Amsler test and fluorescein angiography (FA).

RESULTS

The photoreceptor mosaic was absent in a localized area of the fovea in the images obtained by the AO fundus camera, and the photoreceptor outer segments (OS) were disrupted at the corresponding area in the FD-OCT images. The changes were detected not only in the symptomatic eye but also in the asymptomatic fellow eye in both patients. In 3 eyes, the geographic dark area in the AO image decreased during the follow-up examinations.

CONCLUSIONS

Very small, localized photoreceptor disruptions can be detected in patients with minimal titanium:sapphire laser injury by cross-sectional imaging using OCT, but their extent was delineated more precisely by en face AO imaging. Because the area of the photoreceptor disruption is very small, especially in the nonsymptomatic fellow eye, it is strongly recommended that laser workers--even those without visual symptoms--be examined by FD-OCT, an AO camera, or both if they have not worn protective goggles while using a laser.

Histological evaluation of mechanical epithelial separation in epithelial laser in situ keratomileusis

PURPOSE

To evaluate the effect of mechanical epithelial separation with an epikeratome on the histologic ultrastructure of epithelial flaps and stromal beds from human corneas.

SETTING

Departments of Ophthalmology, Osaka University Medical School, Osaka, and Tohoku University School of Medicine, Sendai, and Institute of Advanced Biomedical Engineering and Science and Medical Research Institute, Tokyo Women's Medical University, Tokyo, Japan.

METHODS

Eye-bank eyes were deepithelialized using an Epi-K epikeratome. Epithelial flaps and stromal beds were assessed by light and electron microscopy. Immunofluorescence staining for types IV and VII collagens, integrins alpha(6) and beta(4), and laminin 5 was also performed.

RESULTS

Four eyes were evaluated. On scanning electron microscopy, the cleavage planes of epithelial flaps and stromal beds were relatively smooth. On transmission electron microscopy, epithelial flaps were separated partially within the lamina fibroreticularis and partially within the lamina lucida. Immunofluorescence showed positive staining for type VII collagen and discontinuous staining for type IV collagen in stromal beds. Discontinuous linear staining for types IV and VII collagens was observed in epithelial flaps. Staining for integrins alpha(6) and beta(4) was positive in some regions and discontinuous in other regions of epithelial flaps. In stromal beds, integrins alpha(6) and beta(4) had a patchy expression pattern. Staining for laminin 5 was intermittently positive along the basal side of epithelial flaps and stromal beds.

CONCLUSIONS

Epithelial flaps created with an epikeratome were mechanically separated partly within the lamina fibroreticularis and partly within the lamina lucida. Stromal beds had relatively smooth surfaces with no obvious trauma to Bowman layer.

Tissue plasminogen activator-assisted vitrectomy: surgical drainage of submacular hemorrhage

A thick subretinal hemorrhage involving the macula is currently treated with pneumatic displacement or surgical removal. We evaluated the long-term effects of tPA-assisted surgical drainage of a submacular hemorrhage by reviewing the medical records of 12 eyes with submacular hemorrhage followed for a mean follow-up time of 6.9 years. The final best corrected visual acuity (BCVA) improved in 10 eyes (83%), was unchanged in 2 (17%), and was reduced in 0 (0%). The mean preoperative BCVA was 6/200, and the best postoperative BCVA was 20/47, and the final BCVA was 20/143. The late postoperative complications, including recurrent submacular hemorrhage, enlargement of the CNV, and retinal degeneration, reduced the final BCVA. These results indicate that tPA-assisted surgical removal of a subretinal hemorrhage can lead to improved long-term vision. Controlling the choroidal neovascularization may be important for retaining the best postoperative vision.

Marginal crack after intravitreal bevacizumab for myopic choroidal neovascularization

PURPOSE

To report new indocyanine green angiographic (ICGA) findings after intravitreal bevacizumab (IVB) for myopic choroidal neovascularization (mCNV).

CASES REPORT

Three eyes of three patients with mCNV were examined with fluorescein angiography (FA) and ICGA using Heidelberg Retinal Angiograph 2 and the conventional fundus camera before and after IVB. The cessation of angiographic leakage on FA was achieved in all eyes (100%) after IVB, however the hypofluorescent line delineating the margin of the neovascular tissue appeared in ICGA seemingly according to the contraction of mCNV. It was not detected either on FA or ICGA with the conventional camera. This hypofluorescence line enlarged over the time.

CONCLUSION

The contraction-associated hypofluorescence line, namely marginal crack line, indicates the early damage of retinal pigment epithelium and seems to lead to expanding macular chorioretinal atrophy typically seen in mCNV.

Ranibizumab (Lucentis) in neovascular age-related macular degeneration: evidence from clinical trials

BACKGROUND

Neovascular age-related macular degeneration (AMD) has a poor prognosis if left untreated, frequently resulting in legal blindness. Ranibizumab is approved for treating neovascular AMD. However, further guidance is needed to assist ophthalmologists in clinical practice to optimise treatment outcomes.

METHODS

An international retina expert panel assessed evidence available from prospective, multicentre studies evaluating different ranibizumab treatment schedules (ANCHOR, MARINA, PIER, SAILOR, SUSTAIN and EXCITE) and a literature search to generate evidence-based and consensus recommendations for treatment indication and assessment, retreatment and monitoring.

RESULTS

Ranibizumab is indicated for choroidal neovascular lesions with active disease, the clinical parameters of which are outlined. Treatment initiation with three consecutive monthly injections, followed by continued monthly injections, has provided the best visual-acuity outcomes in pivotal clinical trials. If continued monthly injections are not feasible after initiation, a flexible strategy appears viable, with monthly monitoring of lesion activity recommended. Initiation regimens of fewer than three injections have not been assessed. Continuous careful monitoring with flexible retreatment may help avoid vision loss recurring. Standardised biomarkers need to be determined.

CONCLUSION

Evidence-based guidelines will help to optimise treatment outcomes with ranibizumab in neovascular AMD.

Retinal and choroidal biometry in highly myopic eyes with spectral-domain optical coherence tomography

PURPOSE

Morphologic changes in the retina and choroid are closely related with high myopia-related diseases. This study was conducted to evaluate the morphologic characteristics of normal highly myopic eyes.

METHODS

Thirty-one phakic highly myopic eyes with no posterior abnormalities (18 patients; mean +/- SD age, 51.7 +/- 11.4 years) were enrolled. Retinal-choroidal thickness at the fovea 1.5 mm superiorly, inferiorly, nasally, and temporally and the choroidal curvature were measured in the 512 x 128 three-dimensional scan mode with spectral-domain optical coherence tomography. The degree of posterior staphyloma was determined as the sum of the vertical distance from the retinal pigment epithelial line beneath the fovea to the nasal, temporal, superior, and inferior edge of the image, including the fovea. The association of clinical data with these parameters was evaluated.

RESULTS

The mean +/- SD central retinal thickness was 200.9 +/- 39.3 microm. The mean choroidal thickness at the fovea (100.5 +/- 56.9 microm) was significantly different from the temporal (125.4 +/- 59.7 microm), nasal (81.9 +/- 35.0 microm), and superior (129.4 +/- 57.5 microm) thicknesses (P < 0.01). Central retinal thickness did not correlate with age, sex, refractive error, axial length, or central choroidal thickness. Central choroidal thickness was significantly associated with refractive error (P < 0.05) and posterior staphyloma height (P < 0.01). Posterior staphyloma height was significantly correlated with refractive error and axial length (P < 0.01). Stepwise analysis indicated that choroidal thickness correlated significantly with age and posterior staphyloma height (P < 0.01).

CONCLUSIONS

Posterior staphyloma formation was a key factor in choroidal thinning in highly myopic eyes. Choroidal thickness had a greater effect than retinal thickness in highly myopic eyes.

[Towards clinical application of a visual prosthesis]

We have conducted studies to develop a visual prosthesis for blind patients with outer retinal disorders such as retinitis pigmentosa, using a suprachoroidal transretinal electrical stimulation (STS) system. The consortium of the Japan Artificial Vision Project brought together medical researchers and engineers in close cooperation. Various aspects of the STS system have been assessed such as safety, stability in animal eyes, measurements of spatial resolution, development of animal models of retinal degeneration, neuroprotective effects of transcorneal electric stimulation, development of a CMOS LSI-based flexible. A unique artificial vision system has been developed using suprachoroidal electrical stimulation. The system provides spatial resolution equivalent to counting fingers. Animal models of external retinal disorders have been developed. Transcorneal electrical stimulation proved successful in providing neuroprotection in these models. The commercially available visual prosthesis will be further developed using the STS system.

Analysis of soluble vascular endothelial growth factor receptor-1 secreted from cultured corneal and oral mucosal epithelial cell sheets in vitro

BACKGROUND

In clinical trials, eyes transplanted with cultured oral mucosal epithelial cell sheets have shown increased neovascularisation compared with eyes treated with cultured corneal epithelial cell sheets. As reported recently, soluble vascular endothelial growth factor receptor-1 (soluble VEGFr-1) is a main factor to maintain a corneal avascularity.

AIM

To investigate soluble VEGFr-1 of cultured corneal epithelial cells (CCE) and cultured oral mucosal epithelial cells (COE) in vitro.

METHODS

Rabbit corneal and oral mucosal epithelial cells were co-cultured with mitomycin C-treated NIH/3T3 cells on culture plates. After CCE and COE were multilayered, culture medium was replaced by basal medium and incubated. Protein secretion of soluble VEGFr-1 was assessed in conditioned medium from CCE and COE by ELISA. Angiogenic potential was examined by invasion, migration assays with human umbilical vein endothelial cells (HUVECs) in addition to recombinant soluble VEGFr-1.

RESULTS

CCE secreted a significantly higher amount of soluble VEGFr-1 than did COE. Recombinant soluble VEGFr-1 significantly suppressed HUVEC migration induced by COE, without suppression in CCE. In conclusion, these findings suggest that low protein levels of soluble VEGFr-1 may lead to corneal neovascularisation after COE sheet transplantation.

Presumed vascular traction-associated recurrence of retinal detachment in patients with myopic macular hole

Optical coherence tomography (OCT) and OCT-ophthalmoscopic examinations were consecutively performed in two patients with focal retinal redetachment despite previously successful repair of the myopic macular hole-related retinal detachment by vitrectomy with removal of the internal limiting membrane. A microfold developed on the redetached retinal surface in both eyes soon after surgery. C-scan analysis by OCT-ophthalmoscope showed that the retinal microfolds coincided with a retinal artery adjacent to the preexisting macular hole. OCT revealed the focal retinal detachment was most prominent beneath the retinal microfold in both study eyes and did not reach the macular hole in one eye. The retinal microfold was most marked at the initiation of the recurrence and then attenuated with the elevation of the detached retina. Inward vascular tractional force appearing as a retinal microfold can be a critical trigger of recurrent retinal detachment in patients with myopic macular hole.

Multi-finger structure and pulsed-powering operation scheme for CMOS LSI-based flexible stimulator for retinal prosthesis

Multi-finger structure was proposed to improve flexibility of the CMOS LSI-based multi-chip retinal stimulator. A dual-finger retinal stimulator was fabricated and its functionality was demonstrated in retinal stimulation experiments on rabbit's retina, We also proposed an idea of pulsed-powering operation scheme for the multi-chip flexible retinal stimulator. We compared the pulsed-powering scheme with conventional one in a simulation, and show that the pulsed-powering can be an alternative operation scheme for the neural stimulator that provides an improved safety to the biological tissue.

Outer retinal folds in highly myopic macular hole and retinal detachment

PURPOSE

To report the intraretinal microstructure in macular hole and retinal detachment in a highly myopic eye using spectral-domain optical coherence tomography.

METHODS

Two eyes of two patients with macular holes and retinal detachment were examined with spectral-domain optical coherence tomography. Fundus photographs and time-domain optical coherence tomography images also were obtained.

RESULTS

Spectral-domain optical coherence tomography disclosed outer retinal fold formation toward the subretinal space at the level of the photoreceptor inner and outer segment layer, the cystoid spaces expanding outside of the macular hole and epiretinal membrane in all eyes.

CONCLUSION

The outer retinal fold may indicate the tension of the inner retina and the redundancy of the outer retina, which may be responsible for the occurrence of macular holes and retinal detachment in these eyes.

Light-controlled retinal stimulation on rabbit using CMOS-based flexible multi-chip stimulator

We implemented a light-sensing function on CMOS-based multi-chip stimulator for retinal prosthesis. Using the light-sensing circuitry attached to each stimulation electrode, the flexible multi-chip stimulator is capable of image-based patterned stimulation. We verified the function of the light-controlled decision based on the light intensity measured just beside the stimulation site. We also experimentally demonstrated in vivo retinal stimulation on rabbit's retina with light-controlled decision. The result of the present work is a simplified demonstration for the concept of retinal prosthesis with on-site imaging.

Pharmacokinetic behavior of intravitreal triamcinolone acetonide prepared by a hospital pharmacy

PURPOSE

We developed a new hospital pharmaceutical preparation of triamcinolone acetonide (TA) for intravitreal injections using sodium hyaluronate as the vehicle. The purpose of this study was to compare the pharmacokinetic behavior of this hospital pharmacy preparation of TA (HPP-TA) to that of a commercial preparation of TA (CP-TA) in rats.

METHODS

We injected the two preparations of TA into the vitreous humor of male Wistar rats. The rats were killed between days 1 and 21, and the concentration of TA in the vitreous was measured by high-performance liquid chromatography to determine the pharmacokinetic parameters. We also examined the microscopic appearance of the TA particles in these preparations.

RESULTS

The elimination half-life was 6.08 days for the CP-TA and 5.78 days for the HPP-TA. A two-compartment model was suitable to approximate the pharmacokinetic behavior of HPP-TA in the vitreous body, but this model was not suitable for CP-TA, because its pharmacokinetic behavior was not sufficiently stable. The particle size of CP-TA was largest, followed by TA powder and HPP-TA. Many particles were agglutinated in the CP-TA preparation, whereas the TA particles were fine and dispersed in the HPP-TA medium.

CONCLUSIONS

The TA particle size and the suspension medium are likely important factors in the preparation of a safe and stable suspension of TA. HPP-TA satisfied these requirements and should be suitable for clinical use.

Generation of a transgenic rabbit model of retinal degeneration

PURPOSE

To generate a transgenic (Tg) rabbit model of retinal degeneration and to characterize the pattern of degeneration by using histology and electrophysiology.

METHODS

Rhodopsin Pro347Leu Tg rabbits were generated by BAC transgenesis. Tg rabbits were identified by Southern blot analysis, and the expression levels were measured by quantitative RT-PCR. Retinal histology was examined by light and electron microscopy and immunohistochemistry. Retinal function was assessed by full-field electroretinograms (ERGs).

RESULTS

Six lines of Tg rabbits were generated, and two lines with higher levels of expression showed rod-dominant progressive retinal degeneration. Retinal histology indicated a marked regional variation in the loss of photoreceptors with the central retina more severely affected than the peripheral retina. The characteristics of the ERGs of transgenic rabbits indicated that the rod components of the ERGs were reduced to only 5% by 48 weeks, whereas the cone components remained at 35% in the wild-type at the same time point. The retinal ultrastructure of Tg rabbits showed a large number of small vesicles that accumulated in the extracellular space of the photoreceptors.

CONCLUSIONS

To the best of the authors' knowledge, this is the first rabbit model of progressive retinal degeneration. Because rabbits have large eyes and are easy to handle and breed, they will provide a useful animal model for the study of the pathophysiology of and new treatments for retinal degeneration.

Human adipose tissue-derived mesenchymal stem cells as a novel feeder layer for epithelial cells

We examined a novel human feeder cell layer of mesenchymal stem cells harvested from human adipose tissues. Gene expression analyses and colony-forming assay with human primary epithelial cells showed that the adipose tissue-derived mesenchymal stem cells produced various factors to support epithelial stem/progenitor maintenance and cell growth. Using the mesenchymal stem cells as novel feeder layers, transplantable epithelial cell sheets could be effectively generated ex vivo on temperature-responsive cell-culture surfaces.

Fundus autofluorescence related to retinal morphological and functional changes in idiopathic macular holes

PURPOSE

To investigate fundus autofluorescence (FAF) characteristics in relation to morphological and functional features of idiopathic macular hole (IMH).

METHODS

Twenty eyes of 20 consecutive patients with stage 3 or 4 macular holes were included. Fundus autofluorescence images were obtained using the Heidelberg retina angiograph 2, retinal structure was evaluated with 3-dimensional (3-D) imaging of Fourier-domain optical coherence tomography (FD-OCT), and retinal function was assessed with microperimetry-1 (MP-1).

RESULTS

Markedly increased FAF in the foveal centre corresponding to the macular hole, confirmed with FD-OCT, was demonstrated in all eyes. A surrounding hypoautofluorescent ring corresponded to the subretinal fluid cuff. The area of relatively reduced FAF around the ring corresponded precisely to retinal oedema. In 15 eyes (75%), a stellate appearance with dark radiating striae was seen in the relatively reduced FAF and was correlated with intraretinal cystic changes in the outer plexiform layer, observed by FD-OCT. Mean preoperative visual acuity was significantly poorer in eyes without a stellate appearance than in those with a stellate appearance (p = 0.023). The MP-1 study confirmed impaired retinal function in the macular hole bed and in the area of the fluid cuff and retinal oedema.

CONCLUSIONS

Fundus autofluorescence imaging reflects anatomic changes and represents the dysfunctional retinal area in IMH. The technique provides 2-D images with 3-D information on the retinal morphology of this disease.