Jun Akiba

Association between the Short-term Natural History of Diabetic Macular Edema and the Vitreomacular Relationship in Type II Diabetes Mellitus

PURPOSE The authors ascertain the association between the short-term natural history of untreated diabetic macular edema and the vitreomacular relationship. METHODS The authors prospectively studied 82 type II diabetic patients with clinically significant macular edema over a six-month period. They used multiple linear regression analysis to evaluate the effect of ten variables on the short-term natural history of macular edema 6 months after diagnosis: age; gender; diabetes duration at diagnosis of macular edema; hemoglobin A1; insulin use; presence of proteinuria; presence of systemic hypertension, cardiac disorders, or both; degree of diabetic retinopathy; history of panretinal photocoagulation; and vitreomacular relationships, as determined by present lens biomicroscopy. RESULTS At study entry, 22 (27%) eyes had vitreomacular separation and 60 (73%) eyes did not. Macular edema spontaneously resolved in 27 (33%) eyes 6 months after diagnosis. Of the 22 eyes with vitreomacular separation at study entry, 12 (55%) had spontaneous resolution of macular edema after 6 months, whereas only 15 of 60 (25%) of the eyes with vitreomacular adhesion at study entry had spontaneous resolution (P = 0.01). Stepwise regression analysis indicated that vitreomacular separation (P = 0.01) and diabetes duration (P = 0.03) contribute to resolution of macular edema. Of the 27 eyes with resolved macular edema, 17 (63%) had improved visual acuity of more than two lines, whereas no eyes had improved visual acuity if macular edema persisted. The prevalence of improved visual acuity of more than two lines was significantly higher in eyes with vitreomacular separation at study entry (36%, 8/22) than in eyes without (15%, 9/60; P = 0.04). CONCLUSION Our findings suggest that vitreomacular separation may promote the spontaneous resolution of diabetic macular edema and consequently improve visual acuity.

Posterior vitreous detachment induced by injection of plasmin and sulfur hexafluoride in the rabbit vitreous.

PURPOSE To investigate whether an injection of plasmin and sulfur hexafluoride (SF6) can induce posterior vitreous detachment (PVD) without vitrectomy. METHODS One eye each of 15 New Zealand white rabbits was assigned to one of three groups. Eyes in group 1 received a vitreous injection of 1 unit of human plasmin (0.1 mL reconstituted in balanced salt solution) and 0.5 mL of SF6; eyes in group 2 received a vitreous injection of plasmin alone; eyes in group 3 received a vitreous injection of SF6 alone. Seven days after injection, all animals were monitored electroretinographically and killed, and the eyes were enucleated. After fixation, scanning electron microscopy was performed. RESULTS In group 1 eyes, the retinal surface was smooth except for the vitreous base, which showed complete separation of the vitreous cortex from the retina, indicating PVD. In group 2 and 3 eyes, sparse collagen fibers remained on the retinal surface. CONCLUSION Vitreous injection of plasmin combined with SF6 can induce PVD without vitrectomy.

Retinal thickness measurements with optical coherence tomography and the scanning retinal thickness analyzer.

Purpose To assess the reproducibility of retinal thickness measurements in normal subjects and to compare foveal thickness using optical coherence tomography (OCT) and the scanning retinal thickness analyzer (RTA). Methods Two examiners performed foveal thickness measurements in 24 eyes of 12 healthy subjects using both OCT and the scanning RTA. Intraclass correlation coefficients (ICC) (intra-examiner and inter-examiner) were calculated for the paired foveal thickness measurements obtained with each instrument. Results The average foveal thicknesses measured with OCT and the scanning RTA were 155.1 ± 14.9 &mgr;m and 107.8 ± 18.6 &mgr;m, respectively. The intra-examiner ICCs from the two sessions using the OCT and the scanning RTA were 0.99 and 0.78 and 0.89 and 0.99, respectively. The inter-examiner ICCs of the OCT and the scanning RTA were 0.99 and 0.99, respectively. There was a significant correlation between the foveal thickness measurements with these two instruments (R2 = 0.629, P < 0.0001). Conclusion The foveal thicknesses measured using OCT and the scanning RTA in healthy subjects agreed with the previously reported data on foveal thickness. Both instruments can reproducibly quantitate foveal thickness.

Prevalence of Posterior Vitreous Detachment in High Myopia

BACKGROUND Posterior vitreous detachment is known to develop early in high myopia. However, the prevalence of posterior vitreous detachment in relation to patient age and degree of myopia has not been studied by modern vitreous examination methods. METHODS The vitreous conditions of 224 eyes with high myopia (> -6 diopters [D]) were examined biomicroscopically with a +90-D present lens and a Goldmann three-mirror contact lens. The vitreous conditions of 220 eyes with emmetropia (between -1 and +1 D) also were studied and served as controls. RESULTS In high myopia, no patients 29 years of age or younger had posterior vitreous detachment. Thereafter, the prevalence of posterior vitreous detachment increased with age (i.e., 23%, 29%, 44%, and 72% in the fourth through seventh decades, respectively, and 100% of patients 70 years or older). Moreover, posterior vitreous detachment developed earlier in severe high myopia (> -10 D) than in moderate high myopia (> -6 to -10 D). In emmetropia, no patients 39 years of age or younger had posterior vitreous detachment, and its prevalence also increased with age (i.e., 8%, 23%, 44%, 74%, and 86% in the fifth through ninth decades, respectively). CONCLUSION In high myopia, posterior vitreous detachment develops increasingly with age and degree of myopia. Although the sample size in each age group was small, the results suggested that posterior vitreous detachment may develop nearly 10 years earlier in highly myopic than in emmetropic eyes.

POSTERIOR VITREOUS DETACHMENT AND NEOVASCULARIZATION IN DIABETIC RETINOPATHY

The authors evaluated the effect of posterior vitreous detachment (PVD) in 172 eyes (114 patients) with nonproliferative diabetic retinopathy on the development of retinal or optic disc neovascularization. Patients were followed for more than 6 months after the initial vitreous examination (mean, 32 months). None of the patients 39 years of age or younger had PVD, but this condition became more prevalent thereafter with age. In 124 eyes of patients 40 years of age or older, neovascularization developed eventually in 20 (22%) of 93 eyes without PVD but in only 1 (3%) of 29 eyes with complete PVD (P less than 0.05). A vitreous examination was invaluable in predicting the development of retinal or optic disc neovascularization in diabetic patients 40 years of age or older.

Retinal detachment associated with a macular hole in severely myopic eyes

PURPOSE To investigate factors associated with extensive retinal detachment in severely myopic eyes with a macular hole. METHOD Fifty-two consecutive eyes with a macular hole and severe myopia were retrospectively studied. RESULTS An extensive retinal detachment, defined as extending beyond the cuff of subretinal fluid, was observed in 37 eyes (71%). Extensive retinal detachment developed in 36 (95%) of 38 eyes with a posterior staphyloma and in one (7%) of 14 eyes without a posterior staphyloma (P<.0001). Extensive retinal detachment also developed in 32 (89%) of 36 eyes with complete posterior vitreous detachment and in five (31%) of 16 eyes without posterior vitreous detachment (P<.0001). CONCLUSION Posterior staphyloma rather than anteroposterior vitreomacular traction may contribute to the development of retinal detachment associated with a macular hole in severely myopic eyes.

Vitreous Findings in Cases of Optic Nerve Pits and Serous Macular Detachment

We examined biomicroscopically the relationship between the optic nerve and the vitreous in 17 eyes of 16 consecutive patients with pits of the optic nerve that demonstrated an associated serous detachment of the macula. The posterior vitreous was attached in 15 eyes (88%); the posterior vitreous was partially detached with a vitreous strand terminating at the optic pit in two eyes (12%). Of the 15 eyes without posterior vitreous detachment, 11 (73%) had an anomalous Cloquets canal that was markedly condensed and terminated at the margin of the pit. During ocular movement, we observed a back-and-forth movement of the anomalous Cloquets canal and a pulsating translucent membrane that covered the pit. Our findings suggest that the intravitreal traction on the optic pit by the anomalous Cloquets canal may have a role in the development of macular detachment.

Natural outcomes of stage 1, 2, 3, and 4 idiopathic macular holes.

AIMS--A study was carried out to ascertain the natural outcome of each stage of idiopathic macular hole. METHODS--One hundred and fifty four eyes with different stages of idiopathic macular holes were retrospectively studied: stage 1 (40 eyes), 2 (25 eyes), 3 (58 eyes), and 4 (31 eyes). RESULTS--Of 27 of 40 eyes with a stage 1 lesion with posterior vitreous attachment to the macula initially, nine (33%) eyes developed a full thickness macular hole. No stage 1 lesions with posterior vitreous separation from the macula initially progressed to full thickness holes. Twenty one (84%) of 25 eyes with a stage 2 lesion, 32 (55%) of 58 eyes with a stage 3 lesion, and five (16%) of 31 eyes with a stage 4 lesion underwent macular hole enlargement during the median follow up period of 3 years. Visual acuity decreased two or more lines of Snellen equivalent during the follow up period in 12 (30%) eyes with a stage 1 lesion, 17 (68%) eyes with a stage 2 lesion, 17 (29%) eyes with a stage 3 lesion, and four (13%) eyes with a stage 4 lesion. The percentage was significantly higher in eyes with stage 2 lesions than the other stages (p < 0.01). CONCLUSION--The results suggest that the different stages of idiopathic macular holes have different natural outcomes, and the management depends on the stage at presentation.

Variations of posterior vitreous detachment

AIMS To identify variations in posterior vitreous detachment (PVD) and establish a clinical classification system for PVD. METHODS 400 consecutive eyes were examined using biomicroscopy and vitreous photography and classified the PVD variations—complete PVD with collapse, complete PVD without collapse, partial PVD with thickened posterior vitreous cortex (TPVC), or partial PVD without TPVC. RESULTS In each PVD type, the most frequently seen ocular pathologies were as follows: in complete PVD with collapse (186 eyes), age related changes without vitreoretinal diseases (77 eyes, 41.4%) and high myopia (55 eyes, 29.6%); in complete PVD without collapse (39 eyes), uveitis (23 eyes, 59.0%) and central retinal vein occlusion (8 eyes, 20.5%); in partial PVD with TPVC (64 eyes), proliferative diabetic retinopathy (30 eyes, 46.9%); and in partial PVD without TPVC (111 eyes), age related changes without vitreoretinal diseases (62 eyes, 55.9%). This PVD categorisation was significantly associated with the prevalence of each vitreoretinal disease (p<0.0001, χ2 test on contingency table). CONCLUSIONS PVD variations can be classified into four types, which is clinically useful because each type corresponds well to specific vitreoretinal changes.

Effect of the vitreous on the prognosis of full-thickness idiopathic macular hole

We studied 112 eyes with full-thickness idiopathic macular holes (mean follow-up period, 5.7 years) to ascertain the effect of the vitreous on prognosis. Eyes were divided as follows: group 1, 58 eyes with no posterior vitreous detachment; group 2, 25 eyes with no posterior vitreous detachment initially and development of complete posterior vitreous detachment during follow-up; and group 3, 29 eyes with complete posterior vitreous detachment. In group 1, the macular hole enlarged in 37 eyes (64%), and the surrounding retinal detachment enlarged in 29 (50%); visual acuity decreased in 20 eyes (34%) by two or more Snellen lines. These percentages were significantly higher than in group 3 (14%, 10%, and 10%; P = .01, P = .01, and P = .03, respectively). Eyes with a full-thickness macular hole with no posterior vitreous detachment may have a greater risk of enlargement of the macular hole and surrounding retinal detachment, and thus a worse prognosis than eyes with posterior vitreous detachment.