Association of the HTRA1 gene variant with age-related macular degeneration in the Japanese population

The purpose of this investigation was to determine whether the high-temperature requirement A-1 (HTRA1) gene polymorphism is associated with age-related macular degeneration (AMD) in native, unrelated Japanese patients. A total of 123 patients with AMD and 133 control subjects without AMD were recruited for this study. The single-nucleotide polymorphism (SNP) rs11200638 in the HTRA1 gene was assessed using a TaqMan assay. The risk A allele frequencies in the AMD cases and control patients were 0.577 and 0.380, respectively, and were associated with a significant risk of developing AMD (p=7.75x10(-6)). The results were more significant in subtype analyses with wet AMD (p=5.96x10(-7)). We conclude that the rs11200638 variant in the HTRA1 gene is strongly associated with AMD in the Japanese population. This result supports the hypothesis that the HTRA1 gene may increase susceptibility to AMD development and can participate in a potential new molecular pathway for AMD pathogenesis by extending this association across diverse ethnicities.

[Case of corneally displaced malignant conjunctival melanoma]

BACKGROUND

We studied the clinicopathologic characteristics in a patient with malignant conjunctival melanoma associated with corneal invasion.

CASE

A 62-year-old man had a small melanocytic lesion of the inferior palpebral conjunctiva. Previously he had undergone excisional biopsy and was diagnosed as having melanocytic hyperplasia without cytological atypia at an other hospital. He developed recurrence and was referred to us. The pigmentary lesion was observed in the entire inferior palpebral conjunctiva. Biomicroscopic examination revealed that there was a granular pigment lesion in the cornea. The patient was diagnosed as having conjunctival melanoma with corneal invasion and treated with orbital exenteration and chemotherapy in our hospital. Clinicopathologic tests revealed malignant melanoma cells invading through the bulbar conjunctiva and into the cornea. Ultrastructural study by electron microscopy of the pigmented tumor cells in the cornea showed several lobations of the nuclei, a large active-appearing nucleolus, and an aberrant granular melanosomal morphology.

CONCLUSIONS

The infiltration of palpebral malignant conjunctival melanoma was limited to the epidermis of the cornea.

Intraocular Biodistribution of Mono-L-aspartyl Chlorin e6 in a Primate Choroidal Neovascularization Model

BACKGROUND AND OBJECTIVE

To describe the biodistribution of a hydrophilic sensitizer, mono-L-aspartyl chlorin e6 (NPe6), in a primate model of choroidal neovascularization (CNV).

MATERIALS AND METHODS

NPe6 (25 mg/kg) and indocyanine green (ICG, 15 mg/kg) were intravenously administered simultaneously in monkeys with laser-induced CNVs. Eyes were enucleated and examined by fluorescence microscopy immediately, 20 minutes, and 1, 4, and 24 hours after dye injection.

RESULTS

Fluorescence peaked in retinal vessels immediately after dye administration; rapid washout began 1 hour postinjection. In contrast, experimental CNV demonstrated little fluorescence immediately after injection, with increased intensity at later time points. Peak dye fluorescence in CNV occurred 1 hour following dye injection. NPe6 fluorescence diminished rapidly and washed out completely by 24 hours. The dye accumulation and retention pattern of ICG dye resembled that of NPe6.

CONCLUSIONS

This study demonstrated the selective accumulation of NPe6 photosensitizer and ICG dye within experimental CNV and rapid clearance from the circulation and retinochoroidal tissue.

Treatment of stage 2 macular hole by intravitreous injection of expansile gas and induction of posterior vitreous detachment

PURPOSE

To demonstrate the morphological and functional outcomes of intravitreous injection of an expansile gas bubble for the treatment of stage 2 macular holes.

DESIGN

Prospective interventional case series.

PARTICIPANTS

Twenty eyes of 20 consecutive patients with unilateral stage 2 macular holes.

METHODS

The patients underwent intravitreous sulfur hexafluoride injection, followed by postoperative facedown positioning for 3 to 5 days. The patients were observed per protocol schedule with complete ophthalmological examination, including determination of corrected visual acuity (VA), slit-lamp biomicroscopic examination, funduscopic examination, and optical coherence tomography (OCT). Follow-up was greater than 12 months for all patients (mean, 19.5).

MAIN OUTCOME MEASURES

Posterior vitreous detachment, anatomical closure of the hole, VA, and hole diameter as measured by OCT.

RESULTS

Detachment of the posterior vitreous at the macula was achieved in 19 of 20 eyes (95%). Ten cases (50%) had anatomical closure of the hole with intravitreous gas injection alone. The remaining 10 cases (50%) achieved anatomical closure of the hole after subsequent vitreous surgery. There was a significant difference in hole diameter (P = 0.004) and in pretreatment vision (P = 4.5x10(-5)) in patients for whom gas alone resulted in hole closure and those proceeding to vitreous surgery. Hole closure by gas injection alone was achieved in 7 of 7 eyes (100%) with pretreatment vision better than 20/40 and in 6 of 7 eyes (86%) when the hole was smaller than 200 mum. There were no major complications in this series of patients. Successfully treated macular holes remained closed at all follow-up points during the study period.

CONCLUSION

An intravitreous injection of an expansile concentration of the inert sulfur hexafluoride gas alone frequently induces detachment of the posterior vitreous in the aged eye. Anatomical closure of the hole without major complications is more likely in smaller holes with better pretreatment vision. This technique may have clinical application for stage 2 holes in selected cases. A number of potential advantages including decreased morbidity and a potential cost savings may result from successful utilization of this procedure.

Transpupillary thermotherapy-induced modification of angiogenesis- and coagulation-related gene expression in the rat posterior fundus

PURPOSE

To study gene expression changes in the rat retina and choroid following transpupillary thermotherapy (TTT) and to identify molecular mechanisms that may enhance treatment of choroidal neovascularization, complicating age-related macular degeneration.

METHODS

One fundus of Brown Norway rats was treated with an 810 nm diode laser while the contralateral fundus received no treatment. The mRNA was extracted and processed for cDNA microarray analysis. Genes with increased expression were validated by semiquantitative reverse transcription polymerase chain reaction (PCR) and quantitative real-time PCR (qRT-PCR).

RESULTS

Of the 14,815 cDNA elements on the array, 12 genes were up-regulated in TTT treated eyes. Upregulation of eight of these 12 genes could be verified by semiquantitative RT-PCR. The eight verified genes were EPCR, IL-1beta, MCP-1, TSP-1, Fgl, Asns, MT-2, and NMDMC, which included 4 angiogenesis- and coagulation-related genes.

CONCLUSIONS

This study demonstrates upregulation of angiogenesis- and coagulation-related genes following TTT. The response profile and its temporal relationships provide insight into the molecular mechanisms that lead to vascular occlusion and antiangiogenesis induced by TTT.

Bilateral Optic Neuropathy Associated with Multiple Myeloma

A 51-year-old man had reduced vision and bilateral optic disc swelling as the initial clinical manifestation of multiple myeloma. Brain imaging failed to disclose any abnormalities. Before any therapy was begun, visual function began to improve substantially. Three months after chemotherapy was started, visual function and optic disc appearance returned to near normal. There were no features to suggest polyneuropathy-organomegaly-endocrinopathy-M protein-skin changes (POEMS) syndrome. Visual loss in myeloma is usually caused by compression or infiltration of the optic nerves by tumor. The mechanism of the optic neuropathy in this case remains unknown.

[Ultra-late phase of indocyanine green angiography in a case with metastatic choroidal tumor]

PURPOSE

To report a case with metastatic choroidal tumor evaluated with ultra-late phase of indocyanine green (ICG) angiography.

CASES

A 43-year-old woman had metastatic choroidal tumor originating from the thymus with an associated serous retinal detachment. ICG video-angiography demonstrated the tumor as hypofluorescent during the arterio-venous phase and hyperfluorescent during the conventional late phase (about 30 minutes after dye injection), and in the ultra-late phase (24 hours after dye injection). The original and metastatic tumors were treated by radiotherapy, resulting in flattening of the choroidal tumor and resolution of the serous retinal detachment. After the treatment, ICG angiography showed decay of ICG fluorescence and no apparent late accumulation of residual ICG in the tumor.

CONCLUSION

In a case with metastatic choroidal tumor, ICG dye accumulated in the tumor tissue before the treatment, but it decreased after treatment. This finding suggested that dye accumulation may be correlated with the tumor activity and requires a further study, enrolling patients with metastatic choroidal tumor for ICG angiographic evaluation.

[Melanoma-associated retinopathy with unknown primary site in a Japanese woman]

BACKGROUND

We report the clinical features of the first case of a Japanese person with melanoma-associated retinopathy.

CASE

A 44-year-old woman complained of photopsia and blurred vision in her right eye, and was treated with steroids for uveitis by an ophthalmologist. She was referred to our hospital for further examination. After one month of treatment, she still complained of photopsia in her right eye. The best corrected visual acuity in the right eye was 0.8 and these was sensitivity loss in the central visual field test. Ophthalmoscopy and fluorescein angiography showed some retinal vasculitis in the right eye. A full-field electroretinogram demonstrated a negative-type electroretinogram (ERG) waveform with attenuation of the b-wave amplitude in the right eye. A dark adaptation test revealed sensitivity loss of the rods. The lymph nodes on the right side of her neck were examined and the diagnosis was made of metastic cutaneous melanoma with unknown primary site; her visual dysfunction was diagnosed as melanoma-associated retinopathy. The retinal inflammation improved after steroid treatment, but her visual dysfunction remained. Chemotherapy and an immunotherapy regimen was begun, but 36 months later she died of metastatic melanoma in the lungs.

CONCLUSIONS

A woman treated for uveitis without any prior systemic and ocular diseases was diagnosed with melanoma-associated retinopathy and metastatic melanoma in the cervical lymph nodes of unknown primary origin. The first ocular symptoms were photopsia and blurred vision, not night blindness. ERG was useful for diagnosing this rare ocular condition in an early stage.

TRANSPUPILLARY THERMOTHERAPY

PURPOSE

To correlate changes in primate fundus after transpupillary thermotherapy (TTT) at two wavelengths.

METHODS

Twelve primate eyes were treated with TTT using a wavelength of 635 nm (n=7) or 810 nm (n=5). Laser parameters were as follows: 635 nm (spot size, 1 mm; duration, 30-8 seconds; and fluence [power over time], 20-91.4 J/cm) and 810 nm (spot size, 2 mm; duration, 60 seconds; and fluence, 96-436 J/cm). Fundus photography, fluorescein and indocyanine green angiography, and enucleation were performed at time 0 or 2 weeks after TTT for histologic analysis.

RESULTS

Threshold for fundus lesions (91.4 J/cm at 635 nm and 191 J/cm at 810 nm), acute and chronic retinal damage shown by histologic analysis (79.2 J/cm at 635 nm and 96 J/cm at 810 nm), and choroidal vessel occlusion (50 J/cm at 635 nm and 96 J/cm at 810 nm) were lower at 635 nm. Disorganization of the retina and retinal pigment epithelium was seen for both wavelengths at time 0 and 2 weeks after TTT. Occlusion of the choriocapillaris and choroidal stromal vessels was noted only in specimens obtained 2 weeks after TTT.

CONCLUSIONS

TTT resulted in acute and delayed damage to the neurosensory retina that persisted at 2 weeks. The 635-nm wavelength demonstrated a lower threshold fluence for visible fundus lesions, retinal damage, and choroidal vascular occlusion than the 810-nm laser.

Laser Photocoagulation and, to a Lesser Extent, Photodynamic Therapy Target and Enhance Adenovirus Vector–Mediated Gene Transfer in the Rat Retina

PURPOSE

To evaluate the transduction efficiency and localization of a reporter gene after intravitreous injection of adenovirus vector in laser photocoagulation (PC)- and photodynamic therapy (PDT)-treated eyes.

METHODS

Adult Lewis rats received fundus PC, fundus PDT, or no treatment. Intravitreous injection of an adenovirus vector containing the construct expressing beta-galactosidase (AdlacZ.11D) was performed in each group. All eyes were then enucleated for histochemistry and processed for quantitative image analysis.

RESULTS

In eyes with no treatment, there was moderate to intense staining for lacZ in the anterior segment, but little in the retina. In eyes treated with PC and PDT, there was significantly more LacZ staining in the retina. The increased staining corresponded closely with the sites treated with PC and PDT. Gene transduction in PC-treated eyes was enhanced and extended to at least 135 days after virus delivery, but not extended in PDT-treated eyes. Gene transfer and expression were targeted and enhanced at the site of laser burns, at all doses tested (3 x 10(5) to 3 x 10(9) particles per eye).

CONCLUSIONS

Compared with untreated eyes, eyes treated with PC and to a lesser extent PDT, manifest increased transduction efficiency, in areas of the retina that are targeted by laser treatment. This finding suggests a new and promising strategy for the treatment of retinochoroidal neovascularization. Adenovirus gene therapy in combination with PC or PDT would have the advantage of increased transduction efficiency; increased duration of transgene expression; targeted delivery; and, potentially, a lower effective dose of virus.

Functional VEGF C-634G polymorphism is associated with development of diabetic macular edema and correlated with macular retinal thickness in type 2 diabetes

Since vascular endothelial growth factor (VEGF) has a strong effect on induction of vascular permeability, VEGF is an attractive candidate gene for development of diabetic macular edema (ME). Among the 378 patients with type 2 diabetes studied, 203 patients had no retinopathy, 93 had non-proliferative diabetic retinopathy (NPDR), and 82 had proliferative diabetic retinopathy (PDR). ME was present in 16 patients with NPDR and 47 patients with PDR. We genotyped three VEGF polymorphisms: C-2,578A, G-1,154A, and C-634G. Genotype and allele distribution of C-634G, but not C-2,578A or G-1,154A, were significantly different between patients with and without diabetic retinopathy. Logistic regression analysis revealed that the C-634G genotype was a risk factor for DR (p = 0.002), and furthermore for ME (p = 0.047), independently from severity of DR, with the -634C allele increasing the risk. Macular thickness measured by optical coherence tomography was correlated with the C-634G genotype, with the trend increasing with the presence of more -634C alleles (p = 0.006). Stepwise regression analysis showed that duration of diabetes and presence of the C-634G genotype were independent predictors of macular thickness. In addition, basic transcriptional activity levels associated with the -634C allele were greater compared to those seen with the -634G allele in human glioma and lymphoblastic T-lymphocyte cells. These results demonstrate that the VEGF C-634G polymorphism is a genetic risk factor for ME as well as DR.

DECREASED ARTERIAL DYE-FILLING AND VENOUS DILATION IN THE MACULAR CHOROID ASSOCIATED WITH AGE-RELATED MACULAR DEGENERATION

PURPOSE

To compare the angioarchitecture of choroidal arteries and veins in patients with age-related macular degeneration (AMD) to the angioarchitecture of age-matched normal subjects using indocyanine green (ICG) angiography.

METHODS

ICG angiography was performed in 35 consecutive AMD patients and 18 normal age-matched volunteers with a fundus ICG camera. ICG video images, including the arterial and venous phases, were quantitatively analyzed using image analyzing software.

RESULTS

In patients with AMD, the choroidal arterioles are dilated, fewer, run a straighter course, and possess fewer bifurcations. The number of choroidal arteries and the macular fluorescent intensity in the arterial phase of choroidal filling was significantly less in patients with AMD as compared to age-matched normal controls (P = 0.008). The mean and maximum caliber of choroidal veins in the macula was dilated in AMD eyes than in age-matched normal control eyes (P < 0.001). There was no statistically significant difference in arterial dye filling or venous caliber observed in AMD eyes, with or without choroidal neovascular membrane (CNV).

CONCLUSION

Choroidal arterial perfusion in the macula was significant decreased in eyes with AMD with and without CNV, and was associated with choroidal venous dilation. These observations implicate poor choroidal perfusion of the macula in the pathogenesis of AMD.

Midperipheral mottling pigmentation with familial choroidal osteoma

PURPOSE

To describe a rare presentation of familial choroidal osteoma in two siblings.

METHODS

The clinical findings in two siblings over 4 years' follow-up.

RESULTS

Two brothers (15 and 12 years old) had bilateral choroidal osteomas. Both had bilateral peripapillary yellowish-white lesions and midperipheral mottling pigment appearance, which are not seen in sporadic cases. Extensive midperipheral area with mottling pigment appearance was noted by fluorescein angiography (FA) as scattered multiple hyperfluorescent dots. The yellowish-white lesions showed diffuse hyperfluorescence with FA and hypofluorescence with indocyanine green angiography (ICG). ICG also revealed irregular hyperfluorescent areas within the tumor, indicating abnormal choroidal vessels on the tumor. In the left eye of the younger brother, the subretinal fibrosis due to choroidal neovascularization superior to the macula extended down toward the foveal region over 2 years, resulting in visual deterioration.

CONCLUSION

The midperipheral mottling pigment appearance of familial choroidal osteoma cases is unique and different from most sporadic cases, suggesting that familial choroidal osteoma might have separate etiologic or modified factors.

[A new approach for studying the retinal and choroidal circulation]

One advantage of advanced computer technology is the high throughput with which the retinal and the choroidal circulation can be evaluated from new aspects. To study the choroidal circulation, we first reevaluated indocyanine green video angiography to improve the visualization of indocyanine green (ICG) images, then applied computer technology to analyze images obtained by an ICG video camera system. We also developed a new instrument to measure oxygen saturation levels in the fundus using spectral retinal imaging technology. I. Choroidal circulation. 1. Reevaluation of ICG video camera system: For this purpose, the bio-chemical nature of ICG was studied. 1) Spectral absorption of ICG: The peak absorption of ICG in distilled water was 780 nm as measured with a spectrophotometer. Its maximum absorption shifted from 780 nm to 805 nm after gradually mixing ICG with human serum protein. Conjugation time of ICG as well as fluorescein sodium with human serum protein was then measured by a stopped flowmeter. It was found that fluorescein sodium conjugated with human serum protein within a few milliseconds, while ICG required more than 600 seconds before equilibrium of the binding was reached. From these observations, we developed a new ICG video system with dual light sources; one, a 780 nm diode laser for the early dye filling phase, and the other, a 805 nm diode laser for the later phase of ICG angiography. 2) Binding properties of ICG in human blood: Blood samples were obtained from three healthy volunteers after intravenous administration of ICG. The resulting plasma samples were fractionated by agarose gel immunoelectrophoresis and polyacrylamide gel DISC electrophoresis. The electrophoretic pattern obtained by each method was observed with an ICG fundus video system. We also studied the affinity of ICG for lipids that are common molecular components of lipoproteins such as high-density lipoprotein (HDL) and low-density lipoprotein (LDL). Four kinds of ICG solutions mixed with phospholipid, free cholesterol, esterified cholesterol, and triacrylglycerol were observed with the ICG fundus video system. Both electrophoretic studies showed that ICG bound intensely to HDL and moderately to LDL, and only the solution with phospholipid fluoresced brightly when observed with the ICG fundus video system. 2. Residual fundus ICG fluorescence: Residual fundus fluorescence observed in the late phase of ICG angiography may be delineated differently in normal subjects and in patients with age-related macular degeneration (ARMD). We performed ICG angiography on 8 normal subjects aged below 36 years (8 eyes), 9 normal subjects aged above 62 years (9 eyes), and 21 patients with ARMD aged 50 to 88 years (37 eyes). The intensity and pattern of fluorescence from angiograms obtained in the ultra-late phase, 24 hours after dye injection, was recorded and analyzed. In the ultra-late phase, 95% of ARMD eyes with choroidal neovascularization (CNV) showed geographic hypofluorescent lesions. These hypofluorescent lesions occurred in 73% of ARMD eyes without CN, while age-matched normal subjects had no hypofluorescent lesions. The mean intensity of fluorescence in the normal elder subject group was significantly higher than that seen in the normal younger subject group. These findings may reflect aging change and bio-distribution of lipid on the Bruch-RPE complex. 3. The early dye filling pattern of the choroid: We performed ICG angiography on 10 healthy young volunteers aged 22 to 26 years (23.4+/-1.3; mean+/-standard deviation) using an improved ICG video camera system. ICG (50 mg) dissolved in 2 ml in distilled water was injected through the antecubital vein. Although the choroidal dye filling varied among subjects, it always began in the macular area. In the 10 subjects, initial dye filling had two patterns: reticular (n=8) and flush (n=2). The choroidal circulation filled completely before the retinal circulation did. Bright fluorescence in the macula and fast blood flow may be correlated with ample blood volume and abundant blood vessels in the macular area. 4. The spreading pattern of ICG fluorescence in the choroid: The ICG images obtained for observing the early dye filling pattern of the choroid were further processed with a computer-assisted image analyzer. Subtracted images were made using the early ICG frames with a time interval of 0.12 second. Ninety frames of time-sequential images for 3 seconds starting from the initial dye appearance in the choroid were prepared to construct an animated image. In the initial phase of eye filling, patchy fluorescence appeared in the fovea. The fluorescence then spread centrifugally in all directions in a wave-like pulsatile manner towards the peripheral fundus with increasing brightness. Thus an animated video of subtracted images allowed us to evaluate flow dynamics at the level of the choriocapillaris. Using this new approach, pathogenic involvement of choroidal circulation in varied chorioretinal diseases such as central serous chorioretinopathy can be studied with precision. II. Retinal circulation. We developed a new device to study the oxygen saturation (OS) levels in a wider fundus area. We call this device a spectral retinal image (SRI) system. We are pursuing the possibility of this instrument being in clinics to evaluate chorioretinal diseases. 1. Introduction of the device: The instrument consists of a Sagnac interferometer that has been mounted on top of a fundus camera, and a software module which consists of an acquisition module and an analysis module. The image acquisition process takes 6 seconds during which the fundus is illuminated by the white incandescent light of the fundus camera at the regular power settings. OS values in each pixel of the fundus image with a 35-degree view can then be estimated from the respective spectrum that is obtained by Fourier-transforming the interferometer signals. Each OS value is represented by a specific color, and each pixel of the fundus image is painted accordingly. 2. Clinical applications. 1) Control study: OS levels of both retinal arteries and veins within a 1 disc diameter (DD) area around the disc were measured from 20 SRIs obtained from 10 healthy volunteers, and were 96.65+/-3.30% and 56.05+/-4.69%, respectively. Then 30 healthy volunteers were recruited for further study in which the OS values were calculated in five retinal regions: (1) juxta-papillary area within 1.75 DD, (2) fovea within 1.0 DD, (3) papillomacular region within 1.0 DD, (4) superior area of the posterior fundus within 1.0 DD, and (5) inferior posterior area of the posterior fundus within 1.0 DD. The OS level of the juxta-papillary area was the highest, while that of the fovea was the lowest and the other three posterior retinal regions were in the middle. Thus OS levels differed at various areas in the retina with statistical significance. In spite of abundant choroidal circulation in the fovea, the overlying retina may have a relative by low oxygen level. As the retinal pigment epithelium may be efficient enough to block the effect of the choroid optically, our results may indicate that the OS levels represent the OS of the retina. 2) Measurement of OS levels in eyes with retinal circulatory disturbances: Eleven eyes of 10 patients with central retinal vein occlusion (CRVO), which showed various degrees of severity, and 4 fellow unaffected eyes of selected patients were examined by both fluorescein angiography (FAG) and the new SRI system. The fluroescein angiograms were correlated with OS maps that were calculated from the SRI. OS grading demonstrated by OS maps correlated well with severity of CRVO, as estimated by FAG. Thus our SRI system is noninvasive with reproducible results, and may prove to be a useful clinical tool to evaluate the degree of retinal ischemia. 3) Measurement of OS levels in eyes with glaucoma: Forty-seven eyes with open angle glaucoma (OAG) of 47 patients and 21 eyes of 21 age-matched normal subjects were recuited for the study. Twelve eyes with low-tension glaucoma (LTG) were included in the OAG eyes and the rest of the OAG eyes had primary OAG. All patients and normal subjects were examined by SRI. Visual field tests for OAG eyes were done with a Humphrey Field Analyzer using the 30-2 program, Swedish interactive threshold argorithm (SITA). OS levels in the retina at 5 different points: superior, inferior, superio- and inferio-temporal, and nasal region within a juxta-papillary area of 200 microm in diameter were calculated from the SRI. OS levels of retinal arteries were also measured and there were no significant differences between OAG and the control group. OAG eyes showed reduced OS levels in the inferio-temporal retina with statistical significance. This observation was more prominent in LTG eyes. The reduced OS levels observed in OAG eyes correlated well with mean deviation (MD) and the sum of total deviation of the 17 points in corresponding areas in the visual field analysis.

Endothelial nitric oxide synthase gene is associated with diabetic macular edema in type 2 diabetes

OBJECTIVE

We examined the endothelial nitric oxide (eNOS) gene polymorphisms to assess its possible association with diabetic retinopathy and macular edema.

RESEARCH DESIGN AND METHODS

A total of 226 patients with type 2 diabetes and 186 healthy subjects were studied. Type 2 diabetic patients consisted of 110 patients without retinopathy, 46 patients with nonproliferative diabetic retinopathy, and 71 patients with proliferative diabetic retinopathy. Diabetic macular edema was present in 48 patients. Three polymorphisms of the eNOS gene were determined: T-786C in the promoter region, 27-bp repeat in intron 4, and Glu298Asp in exon 7.

RESULTS

Close linkage disequilibrium was observed between the T-786C polymorphism and the 27-bp repeat, as has been previously reported, but Glu298Asp was not in linkage disequilibrium with the other two polymorphisms. The eNOS gene polymorphisms were not significantly associated with the presence of retinopathy or with retinopathy severity or type 2 diabetes itself. However, by both association study and multiple logistic regression analysis, the T-786C and 27-bp repeat polymorphisms were significantly associated with a risk of developing macular edema with the -786C allele and the "a" allele increasing the risk.

CONCLUSIONS

The present study suggests that the eNOS gene is a novel genetic risk factor for diabetic macular edema. The eNOS gene polymorphisms may contribute to the development of macular edema by impairing basal eNOS expression and resulting in the breakdown of the blood-retina barrier.

Enhanced documentation of slit-lamp images of the human vitreous stained with fluorescein sodium

BACKGROUND AND OBJECTIVE

To develop a new method to document the slit-lamp image of the vitreous body as stained with fluorescein sodium.

PATIENTS AND METHODS

The system consists of a Goldmann-type slit-lamp biomicroscope, a highly sensitive monochromatic charge-coupled device camera, and a video attachment for real-time observation and recording. As a standard procedure, observation of the vitreous was conducted 60 minutes after intravenous administration of 500 mg of fluorescein sodium. This method was applied to 19 eyes with various eye diseases.

RESULTS

Fine details of the vitreous were observed in all of the eyes. Posterior vitreous detachment could be recorded in 5 of the 19 eyes examined. Vitreoschisis and large lacunae were documented in 11 eyes.

CONCLUSION

This method promises to be of value in detecting early age-related and pathological changes of the vitreous such as posterior vitreous detachment and vitreoschisis in clinics.

Asymmetry of choroidal venous vascular patterns in the human eye

PURPOSE

To describe the angioarchitecture of choroidal veins in normal subjects using indocyanine green (ICG) angiography.

DESIGN

Consecutive observational case series.

PARTICIPANTS

Thirty-six eyes of 33 healthy volunteers ranging in age from 21 to 81 years (50.0+/-18.2 [mean +/- standard deviation]).

METHODS

Indocyanine green angiography was performed with a modified Topcon fundus ICG camera. Montage images were obtained during the venous phase of the ICG angiogram.

MAIN OUTCOME MEASURES

Indocyanine green angiographic montage images covering all areas of the observable fundus.

RESULTS

Eighteen of 36 eyes examined (50%) showed asymmetry of choroidal venous vascular patterns consistent with a preferential route of choroidal venous drainage of the macular region. Twelve of the 18 eyes with a preferred drainage route drained superotemporally; the remaining 6 eyes drained by either an inferotemporal or a superonasal route. A preferential choroidal venous drainage route in the macula was identified with equal frequency in young and old subjects. Of 36 eyes examined, 27 (75%) lacked ICG angiographic evidence of symmetric separation of outer choroidal veins.

CONCLUSIONS

There is ICG angiographic evidence of asymmetry of choroidal venous drainage in one half of normal individuals. The relative frequency of a resulting preferential drainage route in a group of normal subjects and the equal distribution in young and old subjects indicate that this finding is neither pathologic nor attributable to aging. There is also ICG angiographic evidence for a lack of symmetric separation in the outer choroidal venous system in the majority of normal human subjects tested, indicating that classic watershed zones may not be present or are less prominent in this portion of the choroidal vasculature.

COMPARISON OF EPIRETINAL MEMBRANES OF DIFFERING PATHOGENESIS USING OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To compare optical coherence tomography (OCT) images of idiopathic epiretinal membranes (ERMs) with those of secondary ERMs.

METHODS

OCT was performed on 70 eyes of 63 consecutive patients with biomicroscopic evidence of ERMs and 23 eyes of 23 healthy volunteers without ERMs. OCT findings were correlated with the clinical pathogenesis of the ERM.

RESULTS

Evaluation by OCT established that 48 of 70 ERMs were globally adherent to the retina and that 22 of 70 ERMs were focally adherent to the retina. When correlated to clinical pathogenesis, 20% of idiopathic membranes and 52% of secondary membranes were focally attached to the retina. There was a significant difference in the pattern of membrane attachment to the retina in the two pathogenic groups (P = 0.007). Eight of nine eyes with macular pseudoholes were associated with globally adherent membranes.

CONCLUSION

Secondary ERMs are more likely to be characterized by focal retinal adhesion than are primary ERMs. Primary ERMs tend to be globally adherent. This finding may contribute to understanding the underlying mechanisms of ERM formation in different clinical settings.

Intraocular gene transfer of pigment epithelium-derived factor rescues photoreceptors from light-induced cell death

In this study, we investigated whether intraocular gene transfer of pigment epithelium-derived factor (PEDF) ameliorates the extent of light-induced photoreceptor cell death. Lewis rats received intravitreous injection of 3 x 10(9) particles of adenoviral vector expressing PEDF (AdPEDF.11) in one eye and 3 x 10(9) particles of empty adenoviral vector (AdNull.11) in the contralateral eye. The rats were then dark-adapted for 3 days after which they were continuously exposed to fluorescent light (2,500 lux) for 0, 6, 24, 96, and 168 h. Both eyes were then enucleated and processed for morphometric analysis. Cell death in the retina was examined using TUNEL staining with a propidium iodide counterstain. The photoreceptor cell counts in each of the three groups were significantly different (P < 0.001). Eyes that received intravitreous injection of AdNull.11 or no injection showed a greater number of pyknotic photoreceptor cells and a reduced photoreceptor cell density as compared to eyes treated with intravitreous AdPEDF.11 injection. AdNull.11 treated eyes showed a lesser but still significant protection of photoreceptor cells when compared to untreated eyes. Fewer TUNEL-positive photoreceptor cells were present in AdPEDF.11 treated eyes than in AdNull.11 treated or untreated eyes (P = 0.004). The amplitudes of the ERG a-wave, b-wave, and oscillatory potentials (OPs) were increased significantly by treatment (P < 0.05). These data suggest that adenovirus vector-mediated intraocular expression of PEDF significantly increases photoreceptor cell survival following excessive light exposure. Neuroprotection may result from inhibition of light-induced apoptotic processes. This study provides proof of concept for a gene transfer approach to modulating retinal cell death resulting from photo-oxidative damage and supports the hypothesis that gene transfer of PEDF is broadly applicable to modulating apoptosis in the retina.