Akihiro Kakehashi

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.

Comparison of the prevalence of posterior vitreous detachment in whites and Japanese

The vitreous condition of healthy white (n = 551) and Japanese (n = 528) eyes were reviewed and compared with respect to the prevalence of posterior vitreous detachment (PVD) in the two groups. No white or Japanese patient 39 years of age or younger had PVD; the prevalence among those older than 39 increased with age in the fifth through the ninth decades, i.e., respectively, to 4%, 24%, 37% 59%, and 87% in the whites, and to 5%, 21%, 43%, 72%, and 82% in the Japanese. In none of these decades was there any significant difference between the prevalence of complete or partial PVD in the whites and the Japanese. This finding is significant because the vitreoretinal relationship influences the development and prognoses of the various vitreoretinal disorders.

Molecular Mechanisms of Photochemically Induced Posterior Vitreous Detachment

Vitreous gel contraction and syneresis, commonly associated with age- and disease-related posterior vitreous detachment (PVD), were induced by a hematoporphyrin (HP)-photosensitized reaction. Calf vitreous gel was irradiated by white light in the presence of HP. Gel weights of the vitreous samples after 24 h of irradiation decreased by 14%, the irradiated control without HP by 8% and the control with HP stored in the dark by 8%. No significant difference in vitreous gel compressibility was found between the irradiated controls and the irradiated samples. In separate experiments, collagen gel in a glass capillary and hyaluronic acid (HA) were irradiated with white light in the presence of HP. The control collagen gel (irradiated without HP and stored in the dark with HP) decreased in length by 0.6% after 96 h, the experimental gel with HP decreased in length by 1.3 and 1.9% after 24- and 96-hour irradiation by visible light, respectively. The irradiated HA monitored by high-performance liquid chromatography showed a molecular weight decrease in the HP-treated polymer. Because the HP-sensitized reaction predominantly produces singlet oxygen, collagen gel contraction and HA degradation, in this case, are likely caused by this active oxygen species.

Spontaneous Resolution of Foveal Detachments and Macular Breaks

PURPOSEnTo evaluate the mechanism of spontaneous resolution of foveal detachments and idiopathic macular breaks.nnnMETHODSnWe reviewed the records of 139 consecutive eyes (94 patients) with either a foveal detachment or a macular break in patients who were examined between 1989 and 1992. There were 26 men and 68 women (mean age, 66.9 +/- 6.9 years). They were either unoperated on or observed during the period that preceded surgery. Each patient underwent complete ophthalmic examination in addition to slit-lamp photography of the vitreomacular interface and microperimetry with the scanning laser ophthalmoscope.nnnRESULTSnEight eyes demonstrated spontaneous resolution. A foveal detachment was noted in five eyes (five patients) and a stage 2 macular break in three eyes (three patients). The mean duration of observation was 33 months (range, one to 144 months). Resolution of the foveal detachments occurred without the development of posterior vitreous detachment. In each eye, the presence of a pseudo-operculum, indicating vitreofoveal separation, was accompanied by flattening of the foveal detachment without detectable posterior vitreous detachment. The three eyes with stage 2 macular break resolved after premature development of a posterior vitreous detachment.nnnCONCLUSIONSnFoveal detachment and macular break resolution seem to result from the release or weakening of vitreous traction on the fovea. Reattachment of the foveal retina preserves fair to good visual acuity. Surgical intervention is contraindicated (1) in eyes in which foveal detachment flattens and develops a pseudo-operculum and (2) when a posterior vitreous detachment develops in an eye with a stage 2 macular break. Careful biomicroscopic vitreous examination and microperimetry with the scanning laser ophthalmoscope are extremely useful methods for adequate examination of these patients.

Serum-induced collagen gel contraction

Abstract• Purpose: To understand the molecular events underlying disease-related vitreous gel contraction, the effect of serum components on collagen was investigated. • Methods: Bovine vitreous or dermal collagen was incubated with a mixture of transglutaminase (TG; factor XIIIa) and fibronectin (FN), and the biochemical changes of collagen were monitored by gel electrophoresis. In addition, serum-induced changes in the volume of the collagen gel were monitored. • Results: Gel electrophoresis revealed a new high-molecular-weight band (Mr 240 000) presumably due to intermolecular cross-links of collagen peptides and FN. The serum components also were shown to cause a significant decrease in the volume of the collagen gel. • Conclusion. Collagen gel contraction could be attributed to the collagen-FN-collagen cross-links catalyzed by TG.

Retinal Breaks in Diabetic Retinopathy: Vitreoretinal Relationships

We retrospectively reviewed the eyes of 143 patients with tractional retinal detachment caused by diabetes that had been studied biomicroscopically, and, after some exclusions, divided them into two groups: those with retinal breaks (group 1) (16 patients, 16 eyes), and those without retinal breaks (group 2) (127 patients, 161 eyes). The group 1 eyes were further divided into three subgroups: those with retinal tears from limited anteroposterior vitreous traction (subgroup A), those with macular holes in an area without posterior vitreous detachment (subgroup B), and those with oval retinal holes anterior to the anteroposterior vitreous traction (subgroup C). Subgroup C comprised most of the eyes in group 1 (10 eyes) and was the only subgroup that we compared with group 2. Significant differences between subgroup C and group 2 were found in terms of the extent of tractional retinal detachment (P = .002) and the degree of preretinal fibrosis (P = .009). These data suggest that large tractional retinal detachments and extensive preretinal fibrosis are significant risk factors for the development of retinal breaks in proliferative diabetic retinopathy.

Vitreous observation using a CCD camera and a computerized unit for image processing and storage.

Purpose This study was conducted to evaluate a new technique of vitreous observation. Methods The authors used commercially available devices, including a slit-lamp, monochromatic charge coupled device (CCD) camera, and a computerized unit for image processing and storage, to observe the vitreous and the vitreoretinal relationship. Results The authors obtained good images of the vitreous and the vitreoretinal relationship using the new technique. Furthermore, the image stored in the computer could be accessed and used for patient explanations instantly. Conclusion This technique is useful for documenting the vitreous and can help determine the role of the vitreous in many vitreoretinal disorders.

Vitreous photography with a wide-angle funduscopic lens.

A wide-angle funduscopic lens was used to take slit-lamp photographs of the posterior vitreous. The lens was then evaluated for its optics, magnification, field of view, and photographic usefulness and compared with the photographs taken using double aspheric preset lenses. The advantages of the wide-angle funduscopic lens were its wider field of view and ability to photograph the vitreous in the presence of a small pupil and cataract. The drawbacks were the darker image, low magnification, and artifactitious light reflection from the lens. The slit- lamp photographs using the wide-angle funduscopic lens were very useful in some complicated cases.