Posterior lip sclerectomy vs trabeculectomy in West Indian Blacks

Surgical treatment in a West Indian black population with primary open angle glaucoma was randomized to full-thickness posterior lip sclerectomies or partial thickness trabeculectomies. Forty-five posterior lip sclerectomies and 35 trabeculectomies were performed. With a mean follow-up period of 28.3 months, the eyes with posterior lip sclerectomies had lower intraocular pressures, reduced glaucoma medication requirements, and less failures. Decline of visual acuity did not differ significantly between the two groups, but early visual acuity loss due to accelerated cataract formation was noted more frequently with posterior lip sclerectomies. The incidence of flat anterior chambers also did not differ significantly, but shallow anterior chambers were more frequent and persisted for a longer time with posterior lip sclerectomies. Other complications were more frequent with posterior lip sclerectomies. (AU)

Filtration surgery in Black patients: early results in a West Indian population

We reviewed the early results of 80 filtration procedures when used as the initial surgical treatment in a Saint Lucian West Indian black population with primary open angle glaucoma. Two techniques were used: trabeculectomy under a scleral flap with fornix-based conjunctival flap (Group 1) and full thickness posterior lip sclerectomy with limbal-based conjunctival flap (Group 2). Postoperatively, with an average follow-up of six months, Group 2 had significantly lower intraocular pressures, reduced glaucoma medication requirements, and increased cystic pleb formation. Vision did not differ significantly between the two groups postoperatively, although two Group 1 patients developed progressive glaucomaous visual loss. Complications were slightly more frequent in Group 2. The results of this study suggest that a full thickness sclerectomy technique merits consideration as the initial filtration procedure of choice in West Indian blacks with advanced open angle glaucoma.(AU)

Growth of scleral cartilage

The eye wall of most submammalian vertebrates contains an ocular skeleton including a cup of hyaline cartilage in the sclera. During embryonic development the changes in the size and shape of this plate of cartilage match the growth of the choriod coat, pigmented epithelium and neural retina. In microphthalmic eyes which were experimentally produced by draining the vitreous body from the eye during early development, the sclera is smaller in area but thicker than normal. This is also true in spontaneously occurring microphthalmia . Thus, the area of the sclera adjusts to the size of the eye, probably under the control of mechanical factors generated by an expanding vitreous body. The problem remains whether the total mass of sclera continues to increase at a normal or at a reduced rate in eyes growing at subnormal rates. The growth of the untreated sclera was reflected by increases in its water, dry mass, DNA, hydroxyproline and protein nitrogen. There was a relative dehydration of the sclera during its development. The growth of the untreated sclera was reflected by increase in its water, dry mass, DNA, hydroxyproline and protein nitrogen. There was a relative dehydration of the sclera during it development. The sclerae of experimentally produced microphthalmic eyes of 16 days old chick embryos had a smaller wet weight, dry weight, DNA content, hydroxyproline content and protein nitrogen content than did the sclerae of the normal, unoperated contralateral eyes. The low DNA content indicates a failure of the cell population to increase in these slow growing eyes. On the other hand, the ratios of hydroxyproline and protein nitrogen to DNA, are the same in both the microphthalmic and normal eyes indicating that the mean output of extracellular components per cell is the same in both groups. It seems probable, therefore, that the growth of the sclera is regulated by the expanding vitreous body, and this regulation is mediated by the control of the number of cells which are mobilized into the cell population of the sclera (AU)