Lawrence A. Raymond

Neodymium:YAG Laser Treatment for Hemorrhages under the Internal Limiting Membrane and Posterior Hyaloid Face in the Macula

BACKGROUND A dense premacular hemorrhage may occur from proliferative diabetic retinopathy, a ruptured retinal artery macroaneurysm, or Valsalva retinopathy. Spontaneous clearing of the hemorrhage in Valsalva retinopathy usually occurs, taking several months. In diabetic retinopathy, a traction macular detachment may result as early as 5 weeks after the hemorrhage. In diabetic retinopathy or a macroaneurysm, only a fibrotic epiretinal membrane overlying the macula may develop. Observation or vitrectomy is the current way of managing a dense premacular hemorrhage. This study was undertaken to investigate an alternative, neodymium:YAG (Nd:YAG) laser membranotomy, in treating this type of hemorrhage. METHODS Six eyes in six patients had Q-switched Nd:YAG laser treatment to open trapped hemorrhage overlying the macula. One to three laser membranotomies were performed. Colored fundus photographs were obtained before and after the hemorrhage was treated. In some cases, fluorescein angiography was done before the hemorrhage was treated. The size of the pretreated hemorrhage was estimated from the photographs and expressed in disc diameters. Patients with diabetes had panretinal laser before Nd:YAG laser membranotomy. RESULTS The premacular bleeding originated from proliferative diabetic retinopathy in four eyes and from a retinal artery macroaneurysm in two. Average estimated area of the pretreated hemorrhage was 14 disc diameters. Five eyes had marked clearing of hemorrhage and rapid improvement of vision after Nd:YAG laser membranotomy. Average follow-up after laser treatment was 20 months. One diabetic eye required vitrectomy for rebleeding. One eye had little visual improvement due to pre-existing subretinal bleeding. CONCLUSION Neodymium:YAG laser membranotomy seems helpful in rapid clearing of premacular hemorrhage in certain eyes. A randomized prospective study is needed to evaluate observation, vitrectomy, and Nd:YAG laser treatment of dense premacular hemorrhage.

The raccoon ascarid. A probable cause of human ocular larva migrans.

The ability of raccoon roundworm larvae, Baylisascaris procyonis, to produce ocular larva migrans (OLM) was studied in various experimental animals. In addition, the clinical and pathologic lesions were compared to those in suspected cases of human ocular baylisascariasis, in patients with diffuse unilateral subacute neuroretinitis (DUSN). Ocular larva migrans was produced in squirrel monkeys, cynomolgus monkeys, mice, hamsters, grey squirrels, and woodchucks orally infected with B. procyonis eggs. The clinical and histologic lesions were primarily those of retinitis, retinal hemorrhages, retinal tracks, disruption, and vasculitis; pigment migration; choroiditis; vitritis; and free or encysted larvae in ocular and extraocular tissues. The lesions of experimental OLM correlated well with those of suspected cases of human ocular baylisascariasis and DUSN. Based on these studies, B. procyonis of raccoons should be considered as a probable cause of OLM and DUSN in humans.

Large suprasellar aneurysms imitating pituitary tumour.

Two patients had large (20--30 mm) suprasellar aneurysms with clinical findings resembling an expanding pituitary tumour. One aneurysm was giant (30 mm). Its delayed diagnosis for six years led to severe chiasmal compression. The other aneurysm was compressing the optic nerve. Visual improvement resulted after surgery.

Short Posterior Ciliary Artery Insufficiency with Hyperthermia (Uhthoff's Symptom)

Transient visual blurring with heart or exercise (Uhthoffs symptom) is associated with multiple sclerosis. To our knowledge, this is the first report of its occurrence in cases of documented vascular disease. Two patients had insufficiency of the short posterior ciliary circulation. In one it was caused by a carotid occlusion and in the other by cranial (giant-cell, temporal) arteritis. The monocular blurring may have occurred during periods of relative arterial hypotension.

A Case of Syphilitic Uveitis

A 38-year-old man had anterior uveitis that failed to respond to increasingly aggressive therapy with topical and systemic corticosteroids and mydriatrics. His disease progressed to panuveitis and neuroretinitis and was finally cured with penicillin injections for acquired syphilis. He suffered secondary optic nerve atrophy. Because of the resurgence of the incidence of syphilis in the general population and the dire consequences for the patient in the absence of appropriate therapy, the ophthalmologist needs to consider the possibility of syphilis in his patients with uveitis. He should obtain serologic studies for syphilis.

Synthesis of chondroitin sulfate by fibrotic vitreous induced by monocytes and lymphocytes.

Vitreous fibrosis was induced in rabbit eyes by intravitreal injection of monocytes and lymphocytes. The fibrotic vitreous and normal vitreous removed from experimental animals were then incubated with [3H]-glucosamine at 37 degrees C for 24 hr. The newly synthesized 3H-labeled glycosaminoglycans (GAGs) were isolated by 4 M GuHCl extraction followed by pronase digestion. The 3H-labeled GAGs were then characterized by gel-filtration column chromatography and by specific enzymatic degradation, i.e. hyaluronidase, chondroitinase AC and/or chondroitinase ABC. The disaccahrides derived from chondroitinase ABC degradation were identified by thin-layer chromatography. Our results indicated that 91% of the total glycosaminoglycan synthesized by normal vitreous was hyaluronic acid. In contrast, in the fibrotic vitreous, the synthesis of hyaluronic acid was decreased to 30% whereas the synthesis of chondroitin sulfate increased to 47% of the total newly synthesized glycosaminoglycans. Control vitreous which was injected with freeze-thawed monocytes and lymphocytes synthesized 70% hyaluronic acid and 12% chondroitin sulfate although no fibrosis was observed.

Cell density dependency of vitreous fibrosis induced by monocytes and lymphocytes

The possible roles of monocytes and lymphocytes in vitreous fibrosis were examined by injecting various numbers of the peripheral cell types into the rabbit vitreous. Our results indicated that the degree of vitreous fibrosis and the presence of traction retinal detachment corresponded to the number of cells injected. It was suggested that these findings are probably similar to vitreous membrane formation and retinal detachment in various clinical ocular diseases or inflammations in humans.

Sea-Fan Neovascularization in Diabetes with Thalassemia

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