Andrzej W. Fryczkowski

Diabetic choroidal and iris vasculature scanning electron microscopy findings

Scanning Electron Microscopy (SEM) was used to study vascular casts of twenty-four autopsy eyes taken from patients with long-standing insulin-dependent Diabetes Mellitus. These casts were compared to casts of ten ‘normal’ autopsy eyes from patients without a history of diabetes or other vascular disease. The SEM findings in the choroidal vessels of the diabetic eyes included: increased tortuosity, focal vascular dilations and narrowings, hypercellularity, vascular loops and microaneurysm formation, ‘drop-out’ of choriocapillaries, and sinus-like structure formation between choroidal lobules in the equatorial area. In the iris, neovascularization was evident in the vascular casts in cases with clinically recognized rubeosis iridis. These findings indicate that there is significant involvement of the uveal tract in diabetic eyes. The present study strongly supports the Hidayat and Fine light microscopic observation that the diabetic choroid demonstrates significant vascular changes (e.g. narrowed vessels with possible ‘drop-out’ of capillaries and neovascularization). Changes in the diabetic choroid, especially in the choriocapillaris, may be a contributing factor in diabetic retinopathy, resulting in decreased oxygenation of the outer layer of the retina. Short reviews and updated information of diabetic eye disease provide some additional insights into the vascular problems in the eye.

Anatomical and functional choroidal lobuli

The purpose of this paper is to clarify the controversy between anatomists and clinicians regarding the choroidal angioarchitecture. Vascular casts from 36 human and 10 Rhesus monkey eyes were studied using scanning electron microscopy (SEM). Both the human and monkey choriocapillaris (CC) are non-homogenous structures. They have patterns which change from the peripapillary to peripheral areas. Anatomically, the ‘lobular’ appearance of the CC exists only in part of the posterior pole. One or more collecting venules were found in the center of 86% of the anatomical lobules, while a central feeding arteriole was observed in 14%. Both major and minor feeding arterioles supply the CC areas which may be recognized as the choroidal functional vascular unit (CFVU) or functional lobule described in the past by Hayreh. Our vascular casts and SEM study show that the choroidal anatomical lobuli are not identical with those observed by angiographical study. Thus, two distinct models of choroidal lobuli, anatomical and functional, should be recognized. The CFVU seen on fluorescein (FA) and indocyanine green (ICG) angiographies as a lobular appearance is most likely caused by the pressure gradient of the blood flow.

Congenital Glaucoma Associated With Cutis Marmorata Telangiectatica Congenita: Two Case Reports

Two cases of cutis marmorata telangiectatica congenita are described in association with nevus flammeus and congenital glaucoma. Approximately 65 cases have been reported and the association with nevus flammeus and congenital glaucoma has only been reported in one of those cases. Unlike the glaucoma associated with nevus flammeus of Sturge-Weber, this type of congenital glaucoma appears to be associated with an abnormal filtration angle rather than an increased episcleral venous pressure.

Observations on the lobular organization of the human choriocapillaris

Vascular casts (Batson mixture) of ocular angioarchitecture were prepared from ten human orbits removed at autopsy. The age of donor specimens ranged from seven months to 68 years. The time interval between death and injection of the orbits averaged seven hours with a range of five hours. The resulting vascular casts were examined using light microscopy and scanning electron microscopy (SEM). We present photomicrographs of our vascular casts that demonstrate predictable variations of the human choriocapillaris angioarchitecture according to the region of the choriocapillaris under examination (i.e. posterior pole, equatorial, peripheral, peripapillary, or submacular areas). Our discussion represents an effort to help clarify some persistent controversies concerning the human choroidal angioarchitecture.

Blood Vessels of the Eye and their Changes in Diabetes

The ocular vasculature has been the subject of detailed study in the past [2,6,7,13,16,21–24, 27–29,31,34,37–39,41,43,44,46,47], however, in several areas controversies among researchers still exist. For example, does the choroidal vasculature extend into the lamina cribrosa (LC)? What is the exact blood supply to the lamina cribrosa, the region crucial for optic disc changes, where many disorders occur? Further controversies include the choriocapillaris structure, the location of the feeding arteriole (s) and collecting venules (central position of arteriole and peripheral venules) [22,24,37–39,46], or vice versa [27,43], or the mixed distribution of these vessels changing in different areas [13], and the submacular choriocapillaris (with regard to the presence [6,39] or absence [13,23,37,38,46] of the submacular artery).