Cryotherapy and photocoagulation in the management of retinoblastoma: treatment failure and unusual complication.

Ophthalmologists treating children with retinoblastoma need to be aware of the limitations of new forms of therapy and their complications. For this reason the following case of a child with a small peripheral retinoblastoma that failed to respond to treatment with both cryotherapy and photocoagulation is recorded. The development of a rapidly growing juxtapapillary lesion prompted immediate enucleation. Histological examination revealed viable tumor cells remaining in the areas that were previously treated. The juxtapapillary mass consisted of optic nerve and detached peripapillary retina that were "dragged" towards the tumor by a thick fibrocellular membrane containing many myofibroblasts.

Pars plana vitrectomy for asteroid hyalosis.

Asteroid hyalosis is a common, usually asymptomatic, benign vitreous disease affecting older individuals. A case report of an aphakic patient who developed anterior segment complications with no visualization of the fundus is presented. A pars plana anterior and posterior vitrectomy was performed using the Ocutome system. An excellent technical result with moderate restoration of vision was achieved. Preoperative evaluation with ultrasound was helpful. Pathology confirmed the diagnosis of calcium-containing lipids. Other indications for vitrectomy for asteroid hyalosis include retinal detachments in which the tear cannot be seen and diabetic retinopathy in which laser cannot be performed. Differential diagnosis includes synchysis scintillans, which is usually bilateral and seen in younger individuals after severe ocular inflammation, trauma, or hemorrhage.

Normal and staphylomatous sclera of high myopia. An electron microscopic study.

The posterior sclera of three normal eyes and five staphylomatous, myopic eyes was examined by electron microscopy. The following notable differences were found in myopic sclera: a predominantly lamellar, collagen fiber bundle arrangement; a reduction in the diameter of the fibrils; a greater dispersion for the range of fibril diameters; an increase in unusual star-shaped fibrils on cross section; and a greater prevalence of fibril groups with uniform but extremely fine diameters. These findings essentially agree with those in other studies of the myopic sclera. The ultramicroscopic changes encountered inpathologic myopia are judged to be compatible with an abnormal proteoglycan composition of the interfibrillary substance in the ectatic sclera.

Impact resistance of ophthalmic lenses of various strengths and the influence of frame design.

Protection of the eyes by safety type spectacle, sunglass and goggle lenses has received considerable attention in recent years. Such protection can be enhanced by design of the frame. We report from 476 lenses mounted in 238 frames and subjected to 9,397 impacts. Maximum blows were delivered by a one inch diameter steel ball falling from a height of 122 inches. Results indicated that the force required to fracture lenses in plastic frame mountings was more than twice that required for fracture of identical strength lenses in wire rims. Minus cylindrical lenses were the most frangible. The lowest fracture and posterior dislocation rates were found in industrial plastic frames with a retaining lip. Greater energy attenuation can be induced in a heat tempered glass lens by even edge compression. Good lens and frame design, when properly correlated, should provide impact attenuation distinctly exceeding conventional standards.