Prevention of accidental intraocular injection following inadvertent needle perforation of the eyeball.

To prevent accidental intraocular injection after inadvertent single needle perforation of the eyeball, the authors recommend moving the needle and watching for corresponding movement of the globe following peribulbar or retrobulbar placement of the needle and prior to injecting. The authors have found this technique to be safe and reliable, with negligible morbidity.

Cytokines in the vitreous of patients with proliferative diabetic retinopathy.

Sixteen vitreous and paired serum samples from 13 patients with proliferative diabetic retinopathy, vitreous samples from seven cadaveric control subjects, and aqueous humor samples from 15 normal control subjects were assayed for the cytokines interleukin-1, tumor necrosis factor-alpha, interleukin-6, and interferon-gamma. Interleukin-6 was detected in 15 of 16 vitreous samples (94%) from diabetic patients, but it was not detected in any of the aqueous humor samples. Vitreous interleukin-6 levels positively correlated with ocular disease activity. Interleukin-1 was detected in seven of 16 vitreous samples (44%) and in four of ten aqueous humor samples (40%), whereas tumor necrosis factor-alpha and interferon-gamma were never detected in vitreous or aqueous fluid. Serum samples from diabetic patients and control subjects contained comparable low levels of interleukin-6. Interleukin-1, tumor necrosis factor-alpha, and interferon-gamma were not found in any of the sera. Because interleukin-6 can function as B-cell differentiation factor, this cytokine may have a role in immunoglobulin deposition in the ocular tissues and in the immunopathologic characteristics of proliferative retinopathy.

MK-801 protects retinal neurons from hypoxia and the toxicity of glutamate and aspartate.

The protective effect of the anticonvulsant MK-801 and the antitussive dextromethorphan, which are both N-methyl-D-aspartate receptor antagonists, and kynurenic acid, a broad-spectrum excitotoxin antagonist, was tested in cultured rat retinal cells in an hypoxic environment. The protective effect of these antagonists also was tested in cultured retinal cells and in intact adult rat retinas exposed to the exogenous excitotoxins L-glutamic acid and N-methyl-D-aspartic acid. MK-801 and kynurenic acid protected retinal neurons from hypoxic damage and from the toxicity of exogenous L-glutamic acid and N-methyl-D-aspartic acid. Dextromethorphan, a less potent antagonist, did not protect the retinal neurons from hypoxic damage or the toxicity of exogenous L-glutamic acid, but did attenuate N-methyl-D-aspartate toxicity. These results provide evidence that the synaptic release of excitatory transmitters, most likely glutamate and aspartate, mediate the death of hypoxic retinal neurons. Compounds related to MK-801 may have possible therapeutic applications in the management of retinal ischemia.

Interferon-gamma and tumour necrosis factor induce expression of major histocompatibility complex antigen on rat retinal astrocytes.

Cultured rat retinal astrocytes were tested by indirect immunofluorescence staining for their ability to express class I and II major histocompatibility complex (MHC) antigens under basal culture conditions and after three days of stimulation with two recombinant cytokines, rat interferon-gamma (IFN-gamma) and human tumour necrosis factor alpha (TNF alpha). Under basal culture conditions low levels of class I antigens were detected on a small percentage of cells, but there was no visible class II. IFN-gamma and TNF alpha stimulation enhanced class I expression. TNF alpha had no effect on class II expression, whereas IFN-gamma induced the expression of class II in a dose dependent manner. These findings suggest that retinal astrocytes might play a part in immunological events occurring in the retina.

Laser photocoagulation control of diabetic macular oedema without fluorescein angiography.

This study included 40 eyes in 22 diabetic patients with focal macular oedema. Laser photocoagulation was directed at decompensated or leaking microvascular lesions clinically detected without using pretreatment fluorescein angiograms. Post-treatment fluorescein angiograms performed after adequate clinical control of disease showed complete resolution of the macular oedema in 25 eyes (62.5%), whereas persistent leakage from microvascular lesions closer than 500 microns from the centre of the foveola was noted in 15 eyes (37.5%). These were clinically detected during the pretreatment examination and were found not to impair or threaten the patient's vision. Our data confirm the clinical impression that fluorescein angiography is not necessary for effective treatment and should be used only if necessary.

Monochromatic endoillumination for epimacular membrane surgery.

We attempted to simultaneously increase visualization of epimacular membranes and minimize retinal phototoxicity by filtering the light of the endoilluminator during vitreous surgery. The monochromatic filters we employed to eliminate short wavelengths were not useful because they reduced the level of illumination. We advise using the lowest level of illumination possible and an ultraviolet/infrared filter over the light source when working close to the retinal surface. The filter can be adapted to replace the fluorescein filter in the Ocutome console to facilitate insertion and withdrawal.

The relationship between retina surgery and preretinal macular fibrosis.

A prospective study of 440 eyes of 220 patients following successful operations for primary rhegmatogenous retinal detachment (132 eyes) and prophylactic operations for retinal breaks (103 eyes) revealed an incidence of preretinal macular fibrosis (PRMF) of 47% after scleral buckling surgery and 42% after prophylactic laser or cryopexy. The incidence of PRMF was significantly greater in aphakic vs phakic detachments, in detachments with operculated vs horseshoe breaks, in detachments with horseshoe breaks vs lattice degeneration, in detachments involving the macula, after scleral buckling with cryotherapy vs diathermy, and after prophylactic treatment of retinal breaks of fellow eyes with retinal detachment or retinal breaks that had developed postoperative PRMF. Analysis of the data suggests that PRMF is most likely a result of the retinal break, detachment, and subsequent treatment.

Drusen and drusenoid macular lesions.

Yellow-colored lesions with a similar appearance at the level of the retinal pigment epithelium are frequently called drusen. Direct and indirect ophthalmoscopy, slit-lamp and contact lens examination, and fluorescein angiography allow differentiation among true drusen, retinal-pigment-epithelial detachments, and deposits secondary to retinal-pigment-epithelial degeneration. A combination of these lesions may be present in a single eye especially in patients with age-related macular degeneration. It is important to distinguish among these lesions because prognosis and treatment potential vary.

Scleral buckling for retinal separation: with and without encirclement.

Two similar patient populations with previously unoperated, atraumatic, rhegmatogenous retinal separations were surgically treated using the same technique with encircling elements in one series (290 eyes) and without encircling elements in the other (463 eyes). Nine percent of the encircled group remained detached compared with 7.6% in the other group. The reason for ultimate surgical failure in both groups was proliferative vitreoretinopathy. Encirclement offered no advantage with respect to surgical success.

Decompensation of the retinal pigment epithelium and occult choroidal neovascularization: indications for treatment.

Degenerative changes in the retinal pigment epithelium (RPE) may compromise the patient's visual acuity before the development of frank choroidal (subretinal) neovascularization. A decompensation of the barrier function of the RPE may permit accumulation of subretinal fluid and sub- or intraretinal hard, yellow exudate. Laser treatment may control this inimical process which threatens or impairs vision and may prevent or delay its progression.

Prospective rationale for and results of argon laser treatment of patients with branch retinal-vein occlusion.

A prospective study of 50 patients with branch retinal-vein occlusion (BRVO) treated using argon laser photocoagulation within one week of initial examination is presented. Some patients had acute manifestations and others intermediate or chronic manifestations of BRVO. In the absence of serious irreparable vascular damage, as the result of the natural history of the disease, patients with acute disease and good prognostic factors receiving early treatment did uniformly well with decreased morbidity and retention of good visual acuity. Seventy percent of patients with chronic disease and good prognostic factors showed improvement in visual acuity following treatment. Because of the variable amount of irreversible damage from vaso-occlusion and poor prognostic factors, and the duration of the disease process, argon laser treatment often gave a relative success or stabilization. In view of the uncertainty of the outcome of the natural history of BRVO, the abbreviated morbidity and the diminution of secondary complications observed following argon laser treatment, early treatment seems to be appropriate for patients suffering from BRVO.

Retinopathy associated with acute pancreatitis.

Two patients (a 28-year-old woman and a 23-year-old man) with acute pancreatitis developed severe visual loss. The acute stage of retinopathy consisted of retinal edema, cotton-wool patches, and retinal hemorrhages, predominantly in the posterior pole of both eyes. During the five-year follow-up period, visual acuity improved and sequential fluorescein angiography of both patients demonstrated reperfusion of previously occluded retinal vessels. After resolution of the cotton-wool patches, the previously edematous areas were replaced by foci of retinal thinning which created irregularities in the internal limiting membrane light reflex. Visual fields demonstrated scotomas corresponding to the areas of the previous cotton-wool patches.

Laser treatment for retinal vascular diseases.

To obtain a clinically adequate laser lesion one must adjust four variables, namely treatment spot size, duration of application, wavelength, and power. The intensity of the necessary reaction will depend upon the type of disease and lesion being treated. When retinal vascular diseases are treated using the laser, the pattern of laser lesions is determined by the morphology, type, and distribution of the retinal vascular disease. This pattern varies from focal and multifocal direct treatment to ablative techniques from one to four quadrants and maximally four quadrants and treatment within the temporal retinal vascular arcades usually avoiding treatment within the papillomacular bundle.

Argon vs krypton laser lesions: is the wavelength more important than the power.

Conventionally, unnecessarily intense laser power is advocated for the treatment of subretinal neovascular membranes. Among the four variables determining the adequacy of the laser lesion, namely spot size, duration of exposure, wavelength, and power, the latter is seldom if ever directly considered. Patients with subretinal neovascular membranes may be satisfactorily treated using the unfiltered argon blue-green laser wavelengths and reduced power as an additional option to the filtered argon green and wavelength or krypton yellow or red wavelengths.

Autosomal dominant central pigment epithelial and choroidal degeneration.

Eight of nine individuals of a four-generation family had autosomal dominant central pigment epithelial and choroidal degeneration, which was not entirely consistent with previously described central retinal and choroidal degenerations. The early loss of the choriocapillaris with a relative sparing of the sensory retinal and pigment epithelial function is similar to central areolar choroidal degeneration. Ophthalmoscopically, however, the disease resembled the dominant progressive foveal degenerations; except that our patients additionally had multiple peripheral yellow-white lesions. An exceptional finding in our patients was the preservation of good visual acuity despite marked atrophy of the choriocapillaris.