Central sparing in annular macular degeneration

Using fluorescein angiography and monochromatic photography, we measured the size of the central sparing in 45 patients with annular maculopathy (mean +/- S.D., 0.34 +/- 0.15 disk diameter; range, 0.10 to 0.65 disk diameter) and compared it with the size of macular yellow pigment in 40 subjects (mean +/- S.D., 0.31 +/- 0.12 disk diameter; range, 0.1 to 0.5 disk diameter). The close approximation of these values suggested that macular yellow pigment contributed to the annular pattern through a photoprotective mechanism.

Histopathologic findings in Best's vitelliform macular dystrophy

Postmortem donor eyes from a 69-year-old man with Best's vitelliform macular dystrophy showed retinal pigment epithelial cells across the entire fundus that had accumulated an excessive amount of lipofuscin as defined by ultrastructural appearance, autofluorescence studies, and staining properties. Lipofuscin accumulation was particularly notable in some pigment epithelial cells in the fovea. An accumulation of heterogeneous material located between Bruch's membrane and the pigment epithelium in the fovea was believed to represent the location of a previtelliform lesion. This material appeared to be derived from degenerating pigment epithelial cells and contained few intact lipofuscin granules. Foveal photoreceptor loss occurred above the lesion and in midperipheral sites where the subretinal space contained collections of outer segment debris and phagocytic cells. Best's vitelliform macular dystrophy appears to be a generalized disorder of the pigment epithelium that secondarily affects focal areas of the retina.

Modified grid pattern treatment of diabetic perifoveal edema by orange dye laser photocoagulation

Diabetic perifoveal edema is a potentially dangerous condition. A consecutive series of 58 diabetic eyes with fluorescein angiographically verified perifoveal edema and decreasing visual acuity and/or metamorphopsia was treated by orange dye laser photocoagulation in a perifoveal grid pattern. Observation periods ranged from 3 to 74 weeks (median 23.5 weeks). Post-treatment fluorescein angiography showed 51 dry foveas, 5 had discrete residual edemata and 2 were not controlled by fluorescein angiography, but were clinically dry. Metamorphopsia decreased simultaneously in most patients. Two eyes deteriorated more than 2 lines on the Snellen chart. Both developed chronic maculopathy, maybe induced by treatment. Except for these two, we found only minor changes in visual acuities and central visual fields. We find the method to be a relatively safe procedure to dry up diabetic foveal edema.

Microholes of the fovea centralis

Foveal microholes are a possible cause of unilateral or bilateral small central visual defects in the absence of other macular pathology. In 18 eyes of 17 patients we noted the following features: small, dark-reddish holes in the centre of the fovea ranging from 50 to 150 micron in size; normal adjacent retinal pigment epithelium and neuroepithelium; unilateral in most cases; males and females are equally affected; mean age 40 years; insidious onset; no history of direct eye trauma or sungazing; non-progressive; relatively favourable visual outcome; no relationship with regular macular holes; aetiology unknown. These distinctive features justify reporting these patients as an important separate group.

X-linked retinitis pigmentosa. Profile of clinical findings

An evaluation of 56 patients with X-linked retinitis pigmentosa revealed a profile of findings that include the following: night blindness within the first two decades of life; spherical refractive errors of -2.00 diopters or greater in addition to an increased prevalence of a cylindrical correction of +1.50 diopters or greater; appreciable impairment of central visual acuity to 20/200 or less by the fifth decade of life; characteristic patterns of field loss; presence of a foveal lesion in up to 75% of the study group; posterior subcapsular lens opacities; and nondetectable electroretinographic amplitudes in more than two thirds of the patients (using conventional full-field recording procedures). These observations are of general value in diagnosis of this disease and for counseling of patients afflicted with this severe form of hereditary night blindness.

Quantification of macular ischaemia in sickle cell retinopathy

Macular ischaemia has a central role in the pathophysiology and prognosis of retinal macular disease. We attempted to quantitate two of its major components as follows: vascular nonperfusion, by measuring the foveal avascular zone (FAZ), using fluorescein angiography; and functional damage, using automated perimetry of the central 30 degrees. Sickle cell disease was chosen for study because it was considered a prototype for a purely ischaemic retinopathy without an exudative component. We found that the FAZ measurement was reproducible and that the patients with maculopathy had statistically larger FAZs than the normal controls (p = 0.016, Wilcoxon rank sum test). In addition, scotomas measured by visual field perimetry were significantly larger in the sickle cell patients with maculopathy than in those without maculopathy. Our results showed that angiography and perimetry of the central 30 degrees were more sensitive tests for the detection of ischaemic macular disease than visual acuity and that macular ischaemia could be quantified by their use.

Photic maculopathy by arc welding. A case report

The authors report the case of a photic maculopathy that developed in an arc welder after 5 to 10 minutes of exposure to the bright light of an electric arc, even though the young worker was wearing protective eye glasses. Pigmented foveal changes and a small central scotoma in both eyes without anomalies on fluorescein angiography characterized this maculopathy, that had a favorable course with corticosteroid therapy. Aetiopathogenetic aspects are discussed.

Uveal melanomas near the optic disc or fovea. Visual results after proton beam irradiation

Proximity to the disc and fovea is a risk factor for visual loss after proton beam irradiation of uveal melanomas. Of 562 eyes treated over a 10-year period with pretreatment visual acuity of 20/200 or better, 363 (64.6%) contained tumors within 2 disc diameters (DD) of the disc or fovea. Rates of visual loss after treatment to worse than 20/200 and causes of visual decline were evaluated using Kaplan-Meier analysis. Cumulative rates of visual loss among subjects with tumors near the disc or fovea were 33 and 47% 1 and 2 years after treatment compared to 17 and 28%, respectively, for subjects with tumors located farther from both structures. The leading cause of visual loss in the first year among eyes with tumors near the disc or fovea was retinal detachment. Controlling for other predictors of visual loss to worse than 20/200, location near the disc or fovea was independently related to visual loss primarily due to retinal detachment, cataract, and radiation retinopathy. Despite the unfavorable location of these tumors, over half of patients with 20/200 or better pretreatment visual acuity had useful vision 2 years after treatment.

Familial retinoschisis in female patients

We report two female patients, a mother and daughter, with bilateral foveal changes that resembled those of X-linked recessive juvenile retinoschisis. The 23-year-old daughter had flat retinoschisis at the temporal periphery with multiple small inner-layer breaks in both eyes. There was foveal retinoschisis with fine radial folds. The optic disc was dragged to the nasal side. The 49-year-old mother also had foveal retinoschisis in each eye but there was no peripheral retinoschisis. In the left eye several retinal breaks with minimal retinal detachment were found. Electrophysiological findings in both cases were similar. Single-flash electroretinogram (ERG) showed normal a-wave and decreased b-wave, presenting a negative shape. Averaged scotopic and photopic ERGs showed slightly reduced b-waves, but they were within normal ranges. Visually evoked potentials were subnormal. Ophthalmoscopic and electrophysiologic findings were compatible with X-linked recessive juvenile retinoschisis, but an autosomal dominant inheritance was most likely. Our cases do not follow previously reported characteristics and may represent a new clinical entity.

Blood-retinal barrier function in patients with cone or cone-rod dystrophy

We assessed blood-retinal barrier function by vitreous fluorophotometry in 24 patients with either cone or cone-rod dystrophy who were segregated into three subgroups. Compared with a normal population, the patients demonstrated increased vitreous fluorescence (breakdown of the blood-retinal barrier) that positively correlated with peripheral pigmentary changes and an appreciable reduction in electroretinographic scotopic b-wave amplitude. A unique subgroup of three women with supernormal electroretinographic scotopic b-wave amplitudes to a high-intensity stimulus had an abnormal increase in permeability of the blood-retinal barrier even without peripheral pigmentary fundus changes.

Foveal cone pigment density difference and reflectance in retinitis pigmentosa

Cone pigment density difference refers to a change in light absorption by cones before and after bleaching of their visual pigments. With a television ophthalmoscope image processor, we measured the foveal cone pigment density difference in patients with retinitis pigmentosa (RP), good central vision, and no clinically apparent foveal lesion. Foveal reflectance was obtained at 12 different wavelengths of illumination. Compared with similar-aged normal subjects, most patients with dominantly inherited RP had normal or minimally reduced cone pigment density difference within the central fovea, relatively lower than normal density difference at the foveal margin, and increased foveal reflectance. Compared with these normal subjects, patients with recessively inherited RP had significantly reduced cone pigment density difference within the central fovea, relatively more normal density difference at the foveal margin, and normal foveal reflectance.

Albinism

Albinism is the term applied to a heterogeneous group of genetically determined disorders characterized by hypopigmentation and affecting the eyes. After describing the clinical features of albinism in general, the authors discuss the various forms of oculocutaneous albinism, ocular albinism, and albinoidism that are of interest to the ophthalmologist. Emphasis is placed on the ocular features of each form. The visual pathway abnormalities and the clinical management of albinism are discussed.

Simulated treatment of recurrent choroidal neovascularization in primate retina. Comparative histopathologic findings

We simulated the treatment of recurrent choroidal neovascular membranes (CNVM) by applying two courses of laser treatment to monkey retinas. Argon green, argon blue-green, and krypton red lasers (KRLs) were used in juxtafoveal, papillomacular bundle, and nonmacular areas. The effects were examined clinically and histopathologically. Results of once-treated control eyes were consistent with those of previous studies. Repeat treatment, however, resulted in full-thickness retinal destruction or necrosis with all laser modalities and in all fundus locations. These results are consistent with the absorptive characteristics of xanthophyll and melanin and suggest only limited advantages to the KRL when treatment of recurrent CNVM is performed in a previously treated area of the fundus. However, treatment of recurrent CNVM is still probably most successful with a KRL, because recurrent CNVM is usually at a border of a photocoagulation scar, where the retina is still untreated, and because histologic studies have demonstrated inner retinal sparing with a KRL in juxtafoveal areas.

Abnormalities of the foveal avascular zone in diabetic retinopathy

The dimensions of the foveal avascular zone (FAZ) were measured in fluorescein angiograms from 36 diabetic patients and 20 nondiabetic controls. The median values for longest diameter, mean diameter, and circumference were significantly greater in the diabetic group than in the control group. Longest diameters greater than 1.0 mm were found almost exclusively in eyes with proliferative diabetic retinopathy. The FAZ dimensions were strongly positively correlated with the severity of capillary nonperfusion in the posterior retina, but not with fluorescein leakage. The presence of proliferative diabetic retinopathy was also strongly correlated with capillary nonperfusion. Retinal capillary occlusion as the cause of FAZ enlargement in diabetic retinopathy is supported by these findings.

Effect of CW YAG and argon green lasers on experimentally detached retinas

We evaluated the effects of argon-green (514.5 nm) and CW neodymium YAG (1060 nm) wavelengths on experimentally detached retinas of primates. Neither laser produced damage to the sensory retina of the fovea. The argon green wavelength, which was absorbed by haemoglobin in the vessel or by extravasated red blood cells, created vasospasm and nerve fiber layer damage. The beam of the CW YAG was not absorbed by haemoglobin; therefore, no vasospasm could be produced on experimentally detached retinas.

Visual acuity related to retinal distance from the fovea in macular disease

The visual potential of patients with macular diseases involving the fovea has not been adequately documented. We evaluated 55 eyes of patients having discrete macular lesions and related best visual acuity to retinal distance from the fovea. Best visual acuity in the parafoveal area extending from the center of the fovea to a distance of 0.25 disk diameters (DD) away was 20/25 to 20/50; from 0.25 to 0.5 DD, 20/50 to 20/100; from 0.5 to 0.75 DD, 20/100 to 20/200; from 0.75 to 1.0 DD, 20/200 to 20/400; and greater than 1.0 DD, counting fingers. The clinical importance of the findings as they relate to the rationale of laser treatment of macular lesions and to the evaluation of the low-vision is discussed.

Observations on monkey eyes exposed to light from an operating microscope

Two cynomolgous monkeys were exposed to the light of an operating microscope. One eye was exposed to the light with the blue end of the spectrum filtered, while the other was exposed to unfiltered light. Neither group of eyes showed ophthalmoscopic evidence of a discrete retinal lesion. The eyes exposed to unfiltered light, however, showed histologic evidence of foveomacular change. The eyes exposed to filtered light showed lesser changes.

The effects of red krypton and green argon laser on the foveal region. A clinical and experimental study

The destruction of senile neovascular membranes in the central avascular region of the macula by argon laser is difficult and associated with complications. Yellow pigment in this region absorbs the blue component of the conventional argon laser radiation. In this study, the authors used lasers of different wavelengths: red krypton and green argon. Optical and electron microscopic studies on nonhuman primates were performed at 1 hour and 6 weeks. Maximum damage was seen at the level of the internal choroid with krypton laser and at the level of the pigment epithelium with green argon laser. A clinical and angiographic study showed that the destruction of the juxtafoveal neovascular membranes by both lasers was possible. Our clinical experience suggests that the red krypton laser offers a better alternative for treatment of neovascular membranes located near the foveola than the green argon laser.

Effects of argon and krypton laser on experimentally detached retinas

Krypton and argon laser photocoagulation on the foveas and blood vessels of experimentally detached monkey retinas were studied clinicopathologically. In this manner heat transmission from the retinal pigment epithelium (RPE) to the overlying sensory retina was avoided. Krypton lesions bypassed the sensory retina on every occasion to produce major photocoagulative effects at the level of the RPE and choroid. Argon laser wavelengths damaged the overlying retina in the foveal areas as well as in perivascular structures. Although the krypton laser appears preferable for treatment of macular diseases, proper parameters should be used to avoid serious complications.