Showing papers in "Archives of Ophthalmology in 1988"

Idiopathic senile macular hole. Its early stages and pathogenesis.

Abstract: Evidence is presented that idiopathic senile macular hole is caused by focal shrinkage of the vitreous cortex in the foveal area. The most reliable biomicroscopic signs of impending hole formation (stage 1) are the development of a yellow spot or ring in the center of the fovea, loss of the foveal depression, and no evidence of separation of the vitreous from the foveal retina. Although in a majority of eyes with stage 1 changes there is a progression to hole formation, spontaneous separation of the vitreous without hole formation may occur in some cases (44%) and cause characteristic biomicroscopic changes, including foveal reattachment, disappearance of the yellow spot or ring, and, in some cases, a pseudo-operculum, with one or more lamellar holes or facets. A prospective collaborative study is recommended to confirm these findings and to test the clinical value of surgical peeling of the vitreous cortex in eyes with stage 1 changes as a means of preventing hole formation.

Multicenter trial of cryotherapy for retinopathy of prematurity.

Abstract: The multicenter trial of cryotherapy for retinopathy of prematurity (ROP), whose preliminary results are reported in this issue of theArchives, 1 was designed to resolve the uncertainty about the value of treatment and to evaluate its drawbacks and possible benefits. Preliminary results weigh heavily in favor of treatment, and thus constitute an important contribution to the management of ROP, a disorder with the potential to blind many hundreds of premature infants each year. 2 See also pp 457 and 471. By comparing paired sample data from infants with symmetric disease and independent sample data from infants with asymmetric disease in 172 premature infants at 23 centers, the study confirmed that cryotherapy conferred a clear benefit at three months after treatment. The benefit represents an approximate 50% reduction in unfavorable events defined as the presence of a retinal fold, retinal detachment, or retrolental tissue (21.8% of the treated eyes vs

Oral zinc in macular degeneration.

Abstract: Macular degeneration associated with age and drusen, an important cause of severe visual loss in older persons, is of unknown cause. The sensory retina and retinal pigment epithelium, which are cell layers in zinc, appear to be prominently involved in the disease process. Because zinc plays a role in the metabolic function of several important enzymes in the chorioretinal complex, we undertook a prospective, randomized, double-masked, placebo-controlled investigation of the effects of oral zinc administration on the visual acuity outcome in 151 subjects with drusen or macular degeneration. Although some eyes in the zinc-treated group lost vision, this group had significantly less visual loss than the placebo group after a follow-up of 12 to 24 months. This is the first controlled oral intervention study to show a positive, if limited, treatment effect in macular degeneration, a major public health problem. Because of the pilot nature of the study and the possible toxic effects and complications of oral zinc administration, widespread use of zinc in macular degeneration is not now warranted.

Treatment of Chronic Macular Edema With Acetazolamide

Abstract: • In a prospective study, 41 patients with documented chronic macular edema of various causes were entered into a therapeutic trial of acetazolamide sodium, a carbonic anhydrase inhibitor. Each patient received a five-cycle cross-over regimen of treatment/no treatment with a further two cycles of cross-over with another diuretic, cyclopenthiazide, which does not inhibit carbonic anhydrase. At each cross-over patients were examined for evidence of macular edema. Sixteen of 41 patients showed a reproducible response to acetazolamide with partial or complete resolution of edema and improvement of visual acuity. The therapeutic effect occurred in more than half of the patients with inherited outer retinal disease or uveitis, but in none with primary retinal vascular disorders. There was no correlation between the response to treatment and the extent or duration of the edema. No influence of cyclopenthiazide on macular edema was detected.

Results of Optic Nerve Sheath Fenestration for Pseudotumor Cerebri: The Lateral Orbitotomy Approach

Abstract: • Twenty-eight patients with pseudotumor cerebri underwent 40 optic nerve sheath fenestrations for relief of visual loss or to preserve vision. Twenty women and eight men underwent 16 unilateral fenestrations and 12 bilateral operations. Papilledema disappeared or was strikingly reduced in 24 of 28 patients. The other four patients had gliotic discs (two patients) or were followed up for only a short time. Visual acuity improved in 12 of 40 eyes and remained the same in 22 of 40 eyes. Seventeen eyes had preoperative visual acuity of 20/30 or better. In six eyes visual acuity decreased. Of eight eyes operated on that had visual acuity of 20/200 or worse, only three showed improvement. Visual fields improved in 21 of 40 eyes and remained the same in ten eyes. Five of the ten eyes that did not change had poor vision before surgery. Eight eyes in five patients continued to lose acuity postoperatively. Each of these eight eyes had a concomitant loss of visual field. An additional two eyes developed visual field loss with preserved visual acuity. The indications for surgery are early evidence of progressive loss of visual field or acuity in a patient with pseudotumor cerebri. Severe vision loss presents little opportunity for improvement but fenestration may be used in a last effort to preserve or restore vision.

Correlation of Asymmetric Damage With Asymmetric Intraocular Pressure in Normal-Tension Glaucoma (Low-Tension Glaucoma)

Abstract: • If intraocular pressure plays a role in producing visual field loss in normaltension glaucoma, there may be a possible benefit from therapeutic efforts to lower the pressure. To see whether pressure plays a role in the production of damage, we studied 14 cases of normaltension glaucoma with asymmetric intraocular pressure (1- to 6-mm Hg interocular difference in pressure). In 12 of these 14 cases, we found that glaucomatous cupping and field loss (damage) was greater in the eye with higher pressure. This statistically significant correspondence of the higher pressure with the greater visual damage suggests that the level of pressure is a factor in producing optic nerve damage. Other factors also must contribute to account for the few instances in which damage asymmetry did not reflect interocular pressure-difference and for the occurrence of injury at such low levels of pressure in the first place. Although benefit may be expected from therapeutic lowering of pressure in this condition, the degree of benefit, as well as the side effects from treatment required for successful lowering of pressure, remains to be documented by a future clinical trial.

Retinoschisis Associated With Optic Nerve Pits

Abstract: • Stereoscopic transparencies studied with magnification and projection suggest that the retinal elevation that communicates with optic pits is frequently a schisislike separation of the internal layers of retina. Thirteen of 15 eyes with optic pits and maculopathy fit the schisis pattern. Separation of the outer layers of the retina is a secondary phenomenon that starts in the macula.

Antioxidant status in persons with and without senile cataract.

Abstract: • The relationship between biochemical markers of antioxidant status and senile cataract was examined in 112 subjects aged 40 to 70 years. Seventy-seven of these subjects had a cataract in at least one lens. Antioxidant status was measured using erythrocyte superoxide dismutase, glutathione peroxidase, and glucose-6-phosphate dehydrogenase activity, and indexes that included these enzymes plus plasma levels of vitamin E, vitamin C, and carotenoids. Subjects were grouped by level (low, moderate, or high) of the enzymes and antioxidant indexes. Results suggest that subjects with high levels of at least two of the three vitamins (vitamin E, vitamin C, or carotenoids) are at reduced risk of cataract relative to subjects with low levels of one or more of these vitamins (odds ratio, 0.2). The erythrocyte enzymes, either individually or in combination, did not appear to differ between subjects with and without cataract.

Modified optic nerve sheath decompression provides long-term visual improvement for pseudotumor cerebri.

Abstract: • Twenty-three patients with chronic papilledema associated with pseudotumor cerebri underwent "modified" optic nerve sheath decompression for treatment of visual acuity and visual field loss. Instead of removing a single, rectangular section of optic nerve meninges, the operation was modified by making at least three longitudinal incisions in the sheath and then lysing arachnoid adhesions with a tenotomy hook. Twenty-one of the 23 patients demonstrated improved visual function after the initial surgery for a mean (±SD) follow-up of 21.5 ± 12.3 months (median, 25 months; range, three to 45 months) without reoperation or reinstitution or oral corticosteroid and diuretic therapies. The two patients failing to improve after the first surgical procedure initially had a single meningeal window created and subsequently improved following reoperation with the modified procedure. Twelve of 21 patients with bilateral visual loss had improved visual function bilaterally after unilateral surgery. Six of the 21 patients needed bilateral surgery, and the other three had minor visual field defects in the second eye not severe enough to warrant surgery. Preoperative optic disc pallor did not predict a poor postoperative result. Optic nerve surgery improved the visual function in six patients who had failed to recover vision after one or more lumbar-peritoneal shunts.

Implantation of posterior chamber lens in the absence of capsular and zonular support

Abstract: • We have developed surgical techniques for implanting a posterior chamber lens in the absence of capsular and zonular support by securing both haptics of the posterior chamber lens to the sclera at the ciliary sulcus with 10-0 prolene suture. These techniques have been successfully performed and have produced good visual results in six monocularly aphakic patients who had contact lens intolerance and/or contraindications to anterior chamber lens implantations. In consideration of the high incidence and the great variety of complications associated with anterior chamber lenses, these newly developed surgical techniques will be a useful alternative to anterior chamber lenses, even in patients who do not have definite contraindications to anterior chamber lens implantations.

Lens Opacities Classification System.

Abstract: • The Lens Opacities Classification System (LOCS) is a simple system for classifying age-related human lens opacities at the slit lamp or in retroilluminated and slit-lamp photographs. The system employs a set of standard Neitz CTR retroilluminated black-and-white photographs for classification of cortical and posterior subcapsular cataracts and a single color slit-lamp photograph for classification of nuclear color and opalescence. We present a detailed description of the system.

Natural Course of Poorly Defined Choroidal Neovascularization Associated with Macular Degeneration

Abstract: We obtained follow-up data on 84 eyes with age-related macular degeneration and poorly defined angiographic leakage presumed to represent choroidal neovascularization. A poorly defined neovascular membrane was presumed to be present when subsensory retinal fluid was present in association with choroidal leakage on fluorescein angiography and in which the extent of leakage was not well defined. Among the 84 eyes, the average initial visual acuity was 20/80. In 75 (89%) of 84 eyes, the leakage involved the foveal center at initial presentation. At follow-up (average, 28 months; range, six to 53 months), the average visual acuity was 20/250; the final acuity declined at least three but less than six lines in 18 eyes (21%) and six or more lines in 35 eyes (42%). There was a statistically significant difference in the percentage of eyes that developed moderate or severe visual loss among eyes that progressed to disciform scarring compared with eyes that continued to manifest poorly defined leakage without evidence of scarring. Given that most severe visual loss associated with macular degeneration can be attributed to consequences of neovascular membranes and that many membranes associated with age-related macular degeneration are poorly defined, our study results support the possibility that poorly defined neovascular membranes represent a major cause of severe visual loss among the elderly in the United States.

Histopathologic findings in Best's vitelliform macular dystrophy.

Abstract: • 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.

Comparison of the Tono-Pen to the Goldmann Applanation Tonometer

Abstract: • Oculab Tono-Pen tonometry was compared with Goldmann applanation tonometry in 142 eyes of 71 patients without corneal problems. Overall we found 63% of the Tono-Pen readings to be within ±2 mm Hg of the Goldmann applanation tonometry readings and 77% to be within ±3 mm Hg, while 4% were within at least ±7 mm Hg difference. The correlation coefficient between the readings of the two instruments was.84. The mean value of the paired differences was 0.81 ± 3.09 mm Hg overall, −1.78 ± 1.86 mm Hg in the 4 to 10 mm Hg interval, 0.07 ± 2.97 mm Hg in the 11 to 20 mm Hg interval, 1.27 ± 2.62 mm Hg in the 21 to 30 mm Hg interval, and 4.15 ± 2.28 mm Hg in the 31 to 45 mm Hg interval. We conclude that the Tono-Pen measures intraocular pressure in a manner that corresponds well to the Goldmann tonometer in the 11 to 20 mm Hg interval, and fairly well in the 4 to 10 mm Hg and 21 to 30 mm Hg intervals. It lacks good correspondence in the 31 to 45 mm Hg interval.

Prevalence of Good Visual Acuity Following Surgery for Congenital Unilateral Cataract

Abstract: • The prevalence of good visual acuity following surgery for congenital unilateral cataract was examined in a group of patients seen between 1980 and 1986. Overall, 53% of patients obtained linear distance acuities of 20/80 or better by 3 to 7 years of age. The best outcomes followed surgery during the first two months of life, prompt lens fitting, aggressive occlusion therapy, and regular follow-up. Nonetheless, aphakic eyes did not achieve a visual acuity of 20/20 in the sample. Prospective "preferential-looking" data demonstrated a failure of aphakic eyes to keep pace with the normal developmental course after 18 months of age. Poor visual outcomes following late surgery appear to be due primarily to the development of amblyopia during the first months of life, which may aggravate compliance problems and further deteriorate prospects of visual rehabilitation.

Cellular proliferation after experimental glaucoma filtration surgery.

Abstract: We used light microscopic autoradiography to determine the time course of cellular incorporation of tritiated thymidine (a correlate of cell division) following glaucoma filtration surgery in seven eyes of four cynomolgus monkeys with experimental glaucoma. Incorporation of tritiated thymidine was detected as early as 24 hours postoperatively. Peak incorporation occurred five days postoperatively and had returned to baseline levels by day 11. Cells incorporating tritiated thymidine included keratocytes, episcleral cells, corneal and capillary endothelial cells, and conjunctival and corneal epithelial cells. Transmission electron microscopy was correlated with the autoradiographic results to demonstrate that fibroblasts were dividing on the corneoscleral margin. These findings have potential clinical implications for the use of antiproliferative agents after filtration surgery.

Contrast sensitivity in age-related macular degeneration.

Abstract: • Low-contrast charts were used to investigate the possibility that patients with drusen have visual deficits not detected by standard Snellen charts. We compared performance on Regan letter charts between 52 eyes with drusen and Snellen acuity of 20/20 and 27 control eyes. The drusen group read fewer letters than the control group on all of the charts tested. This difference increased as the contrast of the charts decreased. The loss of performance on all of the Regan charts correlated with drusen severity. Twenty-one eyes with drusen and normal Snellen acuity also were tested with a Ginsburg contrast sensitivity chart and compared with age-matched normal controls. The results showed a loss of contrast sensitivity at high spatial frequencies and a loss of peak contrast sensitivity with increasing drusen severity. These results suggest that in patients with drusen, low-contrast charts may be useful for measuring visual loss not detected by standard Snellen charts.

Vitrectomy for macular traction caused by incomplete vitreous separation

Abstract: • Pars plana vitrectomy was performed in 16 eyes to release vitreomacular traction. All patients had a symptomatic preoperative decrease in visual acuity, most often to 20/200. Partial detachment of the posterior vitreous surface was associated with vitreoretinal attachment remaining in the area of the macula and sometimes to the optic nerve head. The posterior vitreous traction on the macula was released by tangential traction on the posterior vitreous surface, causing it to separate from the retina. The postoperative vision was the same or improved in each case. No operative complications occurred, but progressive nuclear sclerosis developed postoperatively in five of the 15 phakic eyes.

Angiographic cystoid macular edema after posterior chamber lens implantation.

Abstract: • We performed a prospective study evaluating the incidence of angiographic cystoid macular edema (CME) following extracapsular cataract extraction and posterior chamber intraocular lens implantation. Of the 162 eyes in the study, 141 were randomized into either a primary capsulotomy or a capsule intact group. The remaining eyes were not randomized due to intraoperative surgical complications, but they were included in the follow-up studies. Six weeks after surgery, angiographic CME was documented in 24% of the capsulotomy group and in 16% of the capsule intact group. The differences were not statistically significant. Including nonrandomized cases reduced the overall incidence of angiographic CME and the difference between the two groups. Angiographic CME was usually not extensive, and it was associated with a visual acuity less than 20/40 in 2.5% of eyes six weeks postoperatively. A subgroup of 120 eyes was followed up for approximately six months, when angiographic CME was present in 4% of the capsulotomy and capsule intact groups.

Optic nerve sheath decompression for pseudotumor cerebri.

Abstract: • We studied optic nerve sheath decompressions for pseudotumor cerebri performed at the Kresge Eye Institute, Detroit, over the past year. Six patients (ten eyes) were operated on. Visual function improved in all ten eyes. A decision to operate was based on progressive loss of visual acuity or visual field unresponsive to medical therapy, accompanied by echographic evidence of a distended optic nerve sheath (positive 30° test). Follow-up ranged from four to 11 months. Four patients underwent subarachnoid iopamidol (Isovue) contrast injection followed by orbital computed tomography. The subarachnoid space totally filled in all patients. No evidence of fibrosis or obstruction of the optic nerve sheath existed; however, leakage of dye from the optic nerve sheath could not be demonstrated. Postoperative complications included transient diplopia and transient atonic pupil (one patient each). Our results indicate that optic nerve sheath decompression improves and protects visual function in patients with pseudotumor cerebri who demonstrate progressive visual field loss and fluid in the optic nerve sheath.

Reliability indexes of automated perimetric tests.

Abstract: • The "reliability" of a subject's automated perimetric test result is generally assessed by three measures: fixation loss and false-positive and false-negative rates. These reliability criteria were examined for 76 glaucomatous and 248 normal subjects who underwent visual field testing (C-30-2 program; Humphrey Visual Field Analyzer, Allergan Humphrey, San Leandro, Calif). Of the examination results, 45% in glaucomatous subjects and 30% in normal controls were considered unreliable with the use of the manufacturer's reliability criteria. Most test results were unreliable because they failed to meet the criterion for fixation loss. The greater rejection rate among glaucomatous subjects was entirely due to their higher rate of false-negative responses. Factors such as age, pupil diameter, and visual acuity did not explain the difference between the false-negative rates of glaucomatous patients and normal subjects.

Sodium Hyaluronate and Polyvinyl Alcohol Artificial Tear Preparations: A Comparison in Patients With Keratoconjunctivitis Sicca

Abstract: • An unpreserved artificial tear substitute containing 0.1% sodium hyaluronate was compared with a preparation containing 1.4% polyvinyl alcohol and 0.5% chlorobutanol in a controlled, double-masked, randomized study in patients with moderately severe keratoconjunctivitis sicca. Patients were evaluated initially, at 1, 4, and 8 weeks. The dry-eye status was evaluated by means of tear-film osmolality, tear breakup time, rose bengal staining, Schirmer's test (without anesthesia), and ocular surface-impression cytology. In general, neither preparation was found to be superior to the other. In both study groups, the mean tear-film osmolality and rose bengal staining score improved over the eight-week study, but the degree of squamous metaplasia of the bulbar conjunctival surface, as shown by impression cytology, did not change significantly.

Choroidopathy in Systemic Lupus Erythematosus

Abstract: Choroidopathy in association with systemic lupus erythematosus (SLE) is a clinically unusual manifestation, previously described in only six patients, to our knowledge. We have followed up six patients with SLE and choroidopathy manifested by multifocal, serous elevations of the retinal pigment epithelium and sensory retina. In four patients, macular involvement was present, and they suffered visual loss. Two eyes of two patients progressed to large, bullous, exudative retinal detachments. In the three patients in whom control of the systemic disease was achieved, the serous detachments resolved. The pathogenesis is most likely related to choroidal vascular disease with resultant pigment epithelial damage and serous fluid leakage beneath the retina.

Trabecular cell division after argon laser trabeculoplasty.

Abstract: • The usefulness of argon laser trabeculoplasty (ALT) in the treatment of some patients with glaucoma has been established; yet, the mechanism of ALT is not understood. The hypothesis that the mechanism involves trabecular cell division was examined. Autoradiographic assessment of tritiated thymidine incorporation into trabecular cell DNA in a human corneoscleral explant organ culture system demonstrated a basal level of DNA replication that increased by 180% in the two days immediately after ALT. When labeling was initiated five days after ALT, DNA replication declined to 70% of the control level. The autoradiographic findings were confirmed using biochemical evaluation of tritiated thymidine incorporation into acid-precipitable macromolecules (DNA) in excised trabecular meshwork. One biologic response of the trabecular meshwork after laser trabeculoplasty is a change in the level of ongoing trabecular cell division.

X-linked Retinitis Pigmentosa Profile of Clinical Findings

Abstract: • 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 −200 diopters or greater in addition to an increased prevalence of a cylindrical correction of ± 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

Prevention of Pericyte Ghost Formation in Retinal Capillaries of Galactose-Fed Dogs by Aldose Reductase Inhibitors

Abstract: • A distinguishing feature of early diabetic retinal vascular changes is the selective degeneration of pericytes (mural cells) from the retinal capillary vessels. Loss of these pericytes has been proposed to be associated with decreased capillary tonicity, the formation of microaneurysms, and vessel dilation. The role of aldose reductase in the progression of diabetic retinopathy has been investigated in age- and sex-matched beagles fed a 30% galactose diet with or without the aldose reductase inhibitors sorbinil or M79175. Eyes were periodically enucleated from dogs in each group and their retinal capillaries were examined as trypsin-digested flat preparations. Before the clinical appearance of retinal changes, pericyte ghost formation was observed in the eyes of three fourths of the dogs after 21 months and all of the dogs after 24 months of galactose feeding. Many of the capillaries containing pericyte ghosts demonstrated an apparent proliferation of endothelial cells and acellular vessels. No pericyte ghosts or abnormal findings were observed in retinas from either normal control (zero of nine) or galactose-fed dogs treated with aldose reductase inhibitors (zero of 16). These findings indicate that aldose reductase inhibitors can prevent the formation of pericyte ghosts and other subsequent capillary changes in experimental retinopathy.

Surgical decompression of branch retinal vein occlusions.

Abstract: • Many patients with branch retinal vein occlusions can develop significant long-term diminution of vision due to such complications as macular edema, retinal neovascularization, and vitreous hemorrhage. One of us (S.C.) developed a new surgical procedure that involves sectioning or decompression of the common sheath connecting the artery and vein at the crossing where a branch retinal vein occlusion occurs. The patient whose case we report had a visual acuity improvement from 20/200−2 to 20/25+1 eight months after surgery.

Surgical management of premacular fibroplasia.

Abstract: • The results of pars plana vitrectomy and membrane peeling for premacular fibroplasia (PMF) were reviewed retrospectively for 88 eyes of 86 patients. Premacular fibroplasia was idiopathic in 61 eyes (69%) and postdetachment in 27 eyes (31%). All patients had a minimum follow-up of 12 months. Visual symptoms of blurring and metamorphopsia were reduced in 75 (85%) study eyes at the end of the follow-up period. Poor visual outcome was significantly related to preoperative cystoid macular edema and pro onged duration of visual blurring. Posterior retinal breaks occurred in three eyes (5%) with idiopathic PMF and five eyes (19%) with postdetachment PMF. Cataract progression was demonstrated in 35 eyes (48%) at 12 months of follow-up and 49 eyes (68%) at 24 months of follow-up, reflecting an incidence of cataract formation that has not been previously reported (to our knowledge) after limited vitrectomy and membrane peeling for PMF.

The incidence of eye injuries in New England adults

Abstract: • A population-based study examined the incidence of eye injuries among New England adults and its association with demographic characteristics and risk-taking behaviors. In 3253 random digit-dialed telephone interviews, 26 adults reported 27 eye injuries during the preceding year, yielding a rate of 9.75 eye injuries per 1000 New England adults. Fifty-nine percent of eye injuries occurred at work. Men had a risk of eye injuries 5.5 times that of women and there was a steep linear decline in eye injury rates with advancing age. Individuals who had other, noneye injuries during the preceding year and individuals who had recently driven after drinking, used marijuana, received a ticket for a moving violation, or not worn seat belts had higher rates of eye injury, but these elevated rates were not statistically significant. Educational and preventive efforts to avoid eye injuries should be directed toward young males in high-risk occupations.

Neovascularization in Central Retinal Vein Occlusion: Electroretinographic Findings

Abstract: • Electroretinograms (ERGs) were measured in 15 patients with central retinal vein occlusion (CRVO). Seven of the patients had neovascularization of the iris (NVI) at the time of testing, and two developed NVI within one month of testing; six did not have NVI or any other form of neovascularization (NV) and were no longer considered to be at risk for NV from their present occlusion. The ERGs were recorded as a function of the stimulus intensity and to a 30-Hz flickering stimulus. A Naka-Rushton-type function was fit to b-wave amplitudes, measured as a function of stimulus intensity, to evaluate changes in ERG amplitude and sensitivity. Compared with eyes in the no-NV group, eyes developing NVI had significantly reduced ERG sensitivity and amplitudes. The distributions of sensitivity values in these two groups did not overlap. All of the eyes with NV showed large a- and b-wave and 30-Hz implicit time delays, but only one eye had a b/ a-wave amplitude ratio close to or less than 1. A comparison of ERG sensitivity, amplitude data, and flicker timing data with retinal fluorescein angiography in a two-alternative forced-choice analysis showed that ERG sensitivity and amplitude loss were better than retinal fluorescein angiography at discriminating eyes with CRVO and NVI from eyes with CRVO without NVI.