A screening approach to the surveillance of patients with diabetes for the presence of vision-threatening retinopathy

OBJECTIVE

To provide scientifically based screening rules for the primary care setting designed to identify, through evaluation of a prescribed and limited portion of the posterior fundus, those patients with diabetes who have retinopathy severe enough to need referral to eye care specialists.

DESIGN

Retrospective analysis of the Early Treatment Diabetic Retinopathy Study (ETDRS) photographic data base.

PARTICIPANTS

The fundus photographic grading data from 3711 patients with diabetes enrolled in the ETDRS.

METHODS

Multivariate regression techniques were used to identify retinopathy lesions in photographic fields 1, 2, 3, or a combination thereof that predict proliferative diabetic retinopathy (PDR) or clinically significant macular edema (CSME) within the seven standard fields. These were used to construct a family of screening rules with optimal combined sensitivity and specificity on which to base referrals to eye care specialists.

MAIN OUTCOME MEASURES

Presence of moderate to severe nonproliferative diabetic retinopathy (NPDR), PDR, or CSME in graded fundus photographs.

RESULTS

Hemorrhages and microaneurysms (h/ma) temporal to the macula (photographic field 3), as severe as or more severe than ETDRS standard photograph 1 (h/ma 3 > or = 3), identified 87% to 89% of eyes with PDR and 92% to 93% of eyes with moderately severe to severe NPDR, which are at high risk for developing PDR. Extrapolating the results using retinopathy prevalence data from epidemiologic studies for the general older onset diabetic population, the calculated sensitivity for detecting PDR on a single examination is 87%, the specificity 80%; for moderate NPDR or worse, the sensitivity is 81 %, specificity 93%. Applying the presence of h/ma 3 > or = 3 as a screening rule to the older onset population, 26.5% of patients would be referred and 73.5% would not be referred. Any hard exudate within one disc diameter of the macular center detects CSME with sensitivity 94%, specificity 54%. Hard exudate of moderate or worse severity anywhere in the macular region (field 2) predicts CSME with sensitivity 89%, specificity 58%.

CONCLUSIONS

Screening protocols based on assessing retinopathy lesion severity in the posterior fundus have the potential to identify most diabetic patients with vision-threatening retinopathy. If the protocols can be implemented effectively in a primary care setting, patients requiring referral for specialty care could be reliably identified, and the total number of patients needing specialty referral could be substantially reduced from current guidelines.

Impaired color vision associated with diabetic retinopathy: Early Treatment Diabetic Retinopathy Study Report No. 15

PURPOSE

To report color vision abnormalities associated with diabetic retinopathy.

METHODS

Color vision function was measured at baseline in 2,701 patients enrolled in the Early Treatment Diabetic Retinopathy Study, a randomized trial investigating photocoagulation and aspirin in the treatment of diabetic retinopathy. Hue discrimination was measured by the Farnsworth-Munsell 100-Hue test, and errors in color vision were reported as the square root of the total 100-Hue (SQRT 100-Hue) score.

RESULTS

Approximately 50% of the Early Treatment Diabetic Retinopathy Study population had color vision scores (SQRT 100-Hue score) worse than 95% of the normal population reported by Verriest and associates. The factors most strongly associated with impaired hue discrimination were macular edema severity, age, and presence of new vessels. A tritan-like defect was prominent and increased in magnitude with increasing severity of macular edema. However, many patients had color discrimination impairment without macular edema.

CONCLUSIONS

Impaired color vision is a common observation among participants enrolled in the Early Treatment Diabetic Retinopathy Study. Compared with published data on normal subjects, approximately 50% of the patients in the Early Treatment Diabetic Retinopathy Study had abnormal hue discrimination. Macular edema severity, age, and the presence of new vessels were the factors most strongly associated with impaired color discrimination. A tritan-like defect was prominent and increased in magnitude with increasing severity of macular edema. Impaired color vision should be considered in the evaluation and counseling of patients with diabetic retinopathy.

Barriers to compliance with screening guidelines for diabetic retinopathy

OBJECTIVE

To identify barriers to compliance with guidelines for diabetic retinopathy screening.

METHODS

The population studied included 4410 adults, aged 31 to 64, enrolled in an Independent Practice Association (IPA) plan in Upstate New York, who were diagnosed with diabetes, and their Primary Care Physicians (408 PCPs). Claims data were used to calculate variables characterizing patients and their PCPs. Logistic regression models were estimated to identify factors associated with higher probability of screening.

RESULTS

34% of patients were screened in 1993. The probability of screening was significantly higher for older patients, for women, for patients who visit their PCPs more often and for those living in areas of higher average education and lower percentage of blacks. However, only 16% of diabetic patients received an annual screen in two consecutive years (1992 and 1993). The probability of consecutive annual screening was significantly associated only with gender and patient expenditures per month.

CONCLUSION

The very low rate of diabetic retinopathy screening has implications for quality of life of patients with diabetes, long term costs of caring for them and social costs due to lost productivity. Interventions to increase screening rates are needed and should target both patients and their Primary Care Physicians.

Brachydactyly-short stature-hypertension (Bilginturan) syndrome: report on two families

We report on two families with autosomal dominant brachydactyly of hands and feet and hypertension. All affected members of the first family had proportionate short stature. However, the propositus and the affected relatives in the second family were only short compared to unaffected relatives. The hypertension was medically responsive in all cases. The propositus in the second family had poor compliance and a striking generalized vasculopathy. All patients were of normal intelligence and had a normal facial appearance. The brachydactyly-short stature-hypertension syndrome was first reported by Bilginturan et al. [1973] in a Turkish family and the families reported by us are Caucasian and Hispanic. The gene causing this condition in the original Turkish family was recently mapped to 12p. Our report expands our existing knowledge and the ethnic diversity of this syndrome.

Macular heterotopia in proliferative diabetic retinopathy

Macular heterotopia secondary to proliferative diabetic retinopathy has been previously reported in clinical cases. To our knowledge, we present the first clinicopathologic case of macular heterotopia in a young patient with proliferative diabetic retinopathy. The significant pathologic findings included dense fibrovascular tissue on the disc to correspond with nasal tractional retinal detachment, a superonasally displaced fovea, and an area of stripped and recoiled internal limiting membrane overlying a retinal fold. In addition, an area of reduplicated retinal pigment epithelium was noted corresponding to the clinically observed hyperpigmented area superior to the heterotopic fovea. Despite the pathologic changes, the patient maintained 20/40 visual acuity with the heterotopic fovea for several years. The findings are discussed in relation to previous clinical studies.

Paraneoplastic retinopathy associated with antiretinal bipolar cell antibodies in cutaneous malignant melanoma

PURPOSE

It has been shown previously that the sera, from patients with visual paraneoplastic syndrome associated with lung cancer, contain immunoglobulins that are reactive with the tumor and with photoreceptor and large retinal ganglion cells. The purpose of this study is to determine the retinal cell population that reacts with immunoglobulins in the sera of patients with melanoma-associated retinopathy.

METHODS

Clinical and electrophysiologic studies were used to determine the locus responsible for the visual defect in each patient. Sera from two patients with melanoma-associated retinopathy, from a patient with herpes zoster, and from a patient who had a colon tumor were obtained. The sera were incubated with sections of retina obtained from a healthy 3-year-old child who had died of asphyxiation. The tissue sections subsequently were incubated with biotin-labeled anti-human immunoglobulin G, and then with streptavidin-labeled peroxidase. Finally, the tissue sections were developed to show peroxidase activity in the targeted retinal cells.

RESULTS

Clinical and electrophysiologic studies were consistent with a defect in intra-retinal transmission distal to the photoreceptors. The immunoglobulins from the patients with the melanoma-associated retinopathy reacted selectively with the bipolar cells of the retina; approximately 30% of the bipolar cells were immunoreactive. The sera from the other two patients were not reactive with any of the retinal cells examined.

CONCLUSIONS

The sera of patients with the paraneoplastic syndrome, melanoma-associated retinopathy, contain high titer immunoglobulins that are reactive only with a subset of the bipolar retinal cells. The clinical, electrophysiologic, and immunologic studies are all consistent with an intra-retinal transmission defect at the level of the bipolar cells.

Methodologic dependence of electroretinogram oscillatory potential amplitudes

The International Society for Clinical Electrophysiology of Vision (ISCEV) protocol for eliciting oscillatory potentials uses a considerably lower flash intensity and a different preconditioning stimulus than the only oscillatory potential protocol used to predict progression of diabetic retinopathy. To determine if the ISCEV protocol will be useful in predicting progression of diabetic retinopathy, summed oscillatory potential amplitudes were measured by both protocols in a population of diabetics. Summed oscillatory potential amplitudes measured by the ISCEV protocol, although smaller, are highly correlated with the summed oscillatory potential amplitudes measured with the higher-intensity flash. Thus, summed oscillatory potential amplitudes measured with the ISCEV protocol should be useful in predicting outcome in diabetic retinopathy. Different signal processing filters used to extract oscillatory potentials from the electroretinogram waveform have a small, but significant, effect on summed oscillatory potential amplitude. Use of the caliper-square method or the summed peak-to-trough method for measuring oscillatory potential heights had an insignificant effect on measured oscillatory potential amplitude.

Lens-corrected visual field sensitivity and diabetes

PURPOSE

To examine whether peripheral S-cone system and achromatic sensitivity was reduced in patients with diabetes compared to normal controls.

METHODS

Perimetric measurements were obtained to study peripheral S-cone system and achromatic sensitivity in patients with diabetes and normal controls. Measures of individual lens absorption of short-wavelength light were used to correct visual field sensitivity values for attenuation of test light due to lens absorption.

RESULTS

Both before and after correction for lens absorption of test spot light, peripheral field-averaged S-cone system and achromatic sensitivities were not significantly reduced among patients with diabetes compared to normals of the same age. However, localized sensitivity losses in the visual field were found in most patients with diabetes both before and after lens absorption correction, compared to age norms. The amount of localized loss (number of field locations with reduced sensitivity) was significantly correlated with the level of retinopathy. Statistical analysis showed that after the effects of age and duration were removed, field-averaged S-cone system sensitivity in patients with diabetes was also significantly reduced as a function of increasing severity of retinopathy.

CONCLUSIONS

Patients with diabetes may have areas of reduced S-cone system sensitivity with development of diabetic retinopathy.

Characterization of the electroretinographic scotopic B-wave amplitude in diabetic and normal subjects

The intensity-response function of the scotopic b-wave of the electroretinogram may be a useful device for monitoring patients with retinal disease. Three models were evaluated that describe this function in 152 patients with diabetic retinopathy of varying severity and in 40 nondiabetic comparison subjects. The models considered were the Naka-Rushton equation fit to all 21 data points collected, the Naka-Rushton equation fit to the data points below the "second limb" of the function, and a log-linear fit only to data at the nine lowest intensities. In addition, the b-wave amplitude at each intensity tested was evaluated individually. Model parameters and amplitude measurements were compared with respect to (1) their ability to distinguish diabetic from nondiabetic subjects determined from the area under the receiver operating characteristic curve and (2) their correlation with retinopathic severity, graded in a standard fashion in fundus photographs. When all the parameters of each model were used in combination, there were no significant differences among the models with either evaluation criterion. Furthermore, b-wave amplitudes at midrange intensities (near -2.2 log cd-sec/m2) did approximately as well as any model.

Autosomal dominantly inherited macular dystrophy with preferential short-wavelength sensitive cone involvement

We found an apparently inherited tritan-like color vision defect in five members of a family, spanning three generations. The defect was associated with mild macular pigmentary changes, poor foveolar reflexes, or slightly reduced visual acuity in four of the affected individuals. The inheritance pattern appeared to be autosomal dominant. Results of various color vision tests indicated preferential involvement of the short-wavelength sensitive cone system, with relative preservation of the middle- and long-wavelength sensitive cone systems. Both anomaloscope testing with larger (8-degree) fields and short-wavelength sensitive electroretinography indicated some short-wavelength sensitive cone system involvement beyond the central macula in the three affected individuals on whom testing was performed. The condition appeared to be a familial macular dystrophy with preferential short-wavelength sensitive cone involvement. The abnormal macular findings and mild reduction in visual acuity distinguish this condition from congenital tritanopia; the normal optic disks distinguish it from autosomal dominant optic atrophy.

Spinocerebellar ataxia, hypogonadotropic hypogonadism, and choroidal dystrophy (Boucher-Neuhäuser syndrome)

We describe two families (including one previously reported) in which cerebellar or spinocerebellar ataxia, hypogonadotropic hypogonadism, and choroidal dystrophy result from abnormal function of an autosomal recessive gene. Review of the literature adds one other family with this disorder. These three examples confirm the existence of this traid as a specific, pleiotropic, single-gene syndrome. Careful ophthalmologic evaluation of patients with ataxia and hypogonadotropic hypogonadism may identify additional cases.

Oscillatory potential amplitudes. Relation to severity of diabetic retinopathy

The oscillatory potentials of the electroretinogram and other visual function tests were evaluated in a group of 174 diabetic and 54 control subjects. Retinopathy severity in diabetic patients was measured in color fundus photographs and fluorescein angiograms. The summed amplitudes of the oscillatory potentials were significantly lower in diabetic compared with control subjects, and the amplitudes decreased progressively as the retinopathy severity increased. Among diabetic patients, a significant correlation was found between the oscillatory potentials and the other visual function tests; lower amplitudes were associated with lower visual field and visual acuity scores and higher Farnsworth-Munsell 100-hue error scores. Stepwise regression analysis showed that the most important predictors of oscillatory potential amplitudes were retinopathy level, fluorescein leakage, and age; capillary nonperfusion did not add to the predictive power of the model when fluorescein leakage was included.

Predicting progression to severe proliferative diabetic retinopathy

The longer-term progression of retinopathy was observed in a previously described group of 85 diabetic patients enrolled in the Early Treatment Diabetic Retinopathy Study. The probability of progression to severe retinopathy was significantly greater for eyes with the following baseline characteristics: greater overall retinopathy severity, higher fluorescein leakage, higher capillary nonperfusion, and lower electroretinographic oscillatory potential amplitudes. The summed amplitudes of the oscillatory potentials, the overall severity of retinopathy, and the severity of fluorescein angiographic leakage were found to be independent predictors of progression to severe proliferative retinopathy in a regression model; capillary nonperfusion was not found to predict progression independently when fluorescein leakage was included in the model. Probability curves based on the regression model can be used to support clinical decisions concerning when to perform panretinal laser photocoagulation and how often to follow up patients with less than severe proliferative diabetic retinopathy.

Temporal aspects of the electroretinogram in diabetic retinopathy

We measured the temporal aspects of several components of the electroretinogram in 72 patients with diabetes and 29 control subjects. The measurements consisted of the implicit times of the a wave and oscillatory potentials elicited by a bright-flash stimulus and the implicit time of the b wave in response to a 30-Hz flickering light. The a wave and first three oscillatory potential nodes were significantly delayed in the patients with diabetes compared with the controls; among the diabetics, a significant increase in the delay of the second and third nodes occurred as a function of increasing retinopathy severity. Similarly, the 30-Hz flicker implicit times (with and without a background light) were significantly delayed in patients with diabetes, and the magnitude of the delay increased with increasing retinopathy severity. The correlations of 30-Hz flicker implicit times with retinopathy severity were significant for retinopathy level graded in color fundus photographs as well as for retinal capillary nonperfusion and leakage graded in fluorescein angiograms. A comparison of 30-Hz flicker implicit times in 15 patients with one eye treated with panretinal laser photocoagulation and the other eye untreated (treatment was randomly assigned) showed a significant delay in the treated eyes compared with the untreated eyes (paired eye comparison). This suggests that panretinal laser photocoagulation induces a further delay in the b-wave implicit times of eyes treated for diabetic retinopathy.

Diabetic macular edema. A review

Diabetic macular edema can be classified into a focal variety, characterized by focal leakage from microaneurysms, often with accumulation of extravascular lipoprotein in a circinate pattern around the focal leakage, and a diffuse variety, with diffuse leakage from retinal vessels often accompanied by cystoid macular changes. Laser photocoagulation is directed at microaneurysms for focal leakage and is applied in a grid pattern for diffuse leakage. Several prospective randomized clinical trials have shown that laser-treated eyes fare better than untreated eyes: there is a higher rate of modest visual improvement and a lower rate of visual deterioration in eyes treated with laser photocoagulation. In patients with diabetic macular edema, especially the diffuse variety, systemic factors also may play a pathogenic role. Fluid retention and hypertension due to cardiovascular and renal disease exacerbate retinal capillary leakage. Correction of systemic abnormalities (reduced blood pressure, diuresis) may reduce macular edema and should be included as part of the total management of patients with diabetic macular edema.

Association of hue discrimination loss and diabetic retinopathy

The results of Farnsworth-Munsell 100-hue, visual acuity, and visual field testing were compared with the severity of retinopathy in a group of 90 diabetic patients. The patients showed significantly higher than expected Farnsworth-Munsell 100-hue scores, with a tritanlike axis, compared with published age norms for nondiabetic individuals. The magnitude of the acquired blue-yellow hue discrimination defect correlated significantly and to a similar extent with both the severity of overall diabetic retinopathy and the severity of macular edema and hard exudate formation. Visual acuity loss correlated somewhat more significantly with macular edema than with overall retinopathy, whereas the converse was true for visual fields. For all visual function tests, the correlations were more significant for fluorescein leakage in the macula than for capillary nonperfusion in the macula. Abnormal hue discrimination was found in 65% (32/49) of eyes with proliferative diabetic retinopathy, suggesting a potential role for this test in screening for proliferative diabetic retinopathy in primary care facilities. Also, because the ability of diabetic patients with color vision deficiency to perform color-dependent tests for urinary and blood glucose may be impaired, such patients should be made aware of this potential problem.

Karsch-Neugebauer syndrome: split foot/split hand and congenital nystagmus

A family with four members with split foot/split hand malformations and congenital nystagmus is described. The clinical characteristics in this family correspond to those seen in two other families previously reported. Taken together, these three families suggest that a single, pleiotropic dominant gene is causal. Karsch-Neugebauer syndrome is suggested as an appropriate eponymic designation for this disorder.

Urinary glucose testing inaccuracies among diabetic patients. Effect of acquired color vision deficiency caused by diabetic retinopathy

The performance of two urinary glucose tests (Clinitest and Diastix) and several color vision and lightness discrimination tests was assessed in 43 diabetic patients and 43 age-matched controls. Most of the diabetics had proliferative diabetic retinopathy, with normal or mildly reduced visual acuity. The diabetics made significantly more errors on color interpretation of the urinary test results than did controls. The extent of errors for both diabetics and controls correlated with the severity of color vision deficiency but not with lightness discrimination deficiency. The diabetics' performance of the Clinitest test and, to a lesser extent, of the Diastix test was significantly better in bright light than in dimmer light. The type of color vision deficiency among most of the diabetics was characteristic of the acquired blue-yellow defect associated with diabetes mellitus. All of the color vision tests enabled identification of patients likely to make a large number of urine-testing errors with high sensitivity and fairly high specificity.

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.

Electroretinographic oscillatory potentials predict progression of diabetic retinopathy. Preliminary report

The oscillatory potential (OP) amplitudes of the electroretinogram (ERG) were determined in a group of 85 diabetic patients entering the Early Treatment Diabetic Retinopathy Study (ETDRS). The rate of progression among nonphotocoagulated eyes to the Diabetic Retinopathy Study high-risk characteristics (DRS-HRC) during a ten- to 40-month follow-up period was determined. Progression occurred in 19 of 85 eyes at risk. Those eyes with abnormal OP amplitudes (less than or equal to 75 microV) at study entry had a tenfold higher rate of progression to DRS-HRC than did eyes with normal amplitudes (greater than 75 microV). Although the level of retinopathic severity at study entry was a significant factor in the rate of subsequent progression, the amplitudes of the OPs remained a significant risk factor even after correcting the initial retinopathic level. The ERG seems to be a useful clinical tool in predicting the rate of progression of diabetic retinopathy. The reduction in OP amplitudes probably is a quantitative measure of the degree of overall inner layer retinal ischemia.

Autosomal dominant peripheral preretinal deposits

Abnormal yellow-white peripheral preretinal deposits are described as an autosomal dominant disorder in ten members of a large pedigree spanning three generations. The absence of any other major vitreoretinal abnormalities or retinal function disorders suggests that this is a benign disease; the nature and origin of the preretinal deposits is obscure.

Diabetic maculopathy. A critical review highlighting diffuse macular edema

Retinal ischemia and edema are the two major intraretinal components of diabetic maculopathy. Focal macular edema is caused by focal leakage from retinal microaneurysms and dilated capillary segments; diffuse edema is caused by leakage from diffusely dilated retinal capillaries throughout the posterior pole. Diffuse macular edema may be exacerbated by systemic factors such as cardiac or renal failure, and hypertension. It is postulated that dysfunction of the retinal pigment epithelial barrier and transport functions might contribute to the problem of diffuse macular edema. Newer techniques of laser grid photocoagulation for diffuse edema have been proposed. It is postulated that photocoagulative debridement of a disordered retinal pigment epithelium could be a mechanism of action of this treatment.

Butterfly-shaped macular dystrophy in four generations

Four generations in a family were affected by butterfly-shaped macular dystrophy. Affected members ranged in age from 8 to 77 years. In addition to the primary features of autosomal dominant inheritance, bilateral symmetrical pigmented macular lesion, and a low electrooculographic light peak-dark trough ratio, we discovered additional progressive changes: peripapillary and parafoveal chorioretinal atrophy, enlarged blind spots, and paracentral scotomas with diminished visual acuity late. Because of the progressive change in the ophthalmologic appearance of the fundus, the diagnosis could easily be overlooked in advanced cases.

New visual acuity charts for clinical research

Three new visual acuity charts facilitate quantitative use of visual acuity test results. The charts have high-contrast lettering on washable white polystyrene. Each line has five Sloan letters; the lines are of equal difficulty and there is a geometric progression in letter size from line to line. This provides a similar task for each line on the chart with the letter size being the only variable. Charts with different letter sequences are used for testing right and left eyes.

Visual function abnormalities in macular heterotopia caused by proliferative diabetic retinopathy

In seven patients with displacement of the macula in one eye caused by vitreoretinal traction from proliferative diabetic retinopathy, the macula was displaced toward the optic disk in all but one eye. The eyes with macular heterotopia showed (1) reduced visual acuity (ranging from 6/6 (20/20) to 6/24 (20/80), (2) reduced static perimetry sensitivity (particularly in the temporal field) with displacement of the peak sensitivity toward the blind spot, (3) loss of hue discrimination, and (4) metamorphopsia. In two eyes with macular heterotopia, Stiles-Crawford data provided evidence for photoreceptor disorientation; one eye had mixed orientation, and the other a displaced peak suggesting regular photoreceptor tilting. The proposed mechanisms of visual loss in eyes with macular heterotopia secondary to traction from proliferative diabetic retinopathy include detachment of the macula, disorientation of photoreceptors in the macula, and disturbance of normal neural connections within the retina caused by stretching of the retina.

Choroidovitreal neovascular ingrowth after photocoagulation for proliferative diabetic retinopathy

In eight patients with proliferative diabetic retinopathy treated with focal photocoagulation for preretinal new vessels, recurrent preretinal new-vessel systems supplied from the choroid developed. Subsequent treatment in most cases failed to produce permanent obliteration of the new-vessels networks.

Pars plana vitrectomy. Treatment for tractional macula detachment secondary to proliferative diabetic retinopathy

Pars plana vitrectomies were performed on 43 eyes with traction macular detachment secondary to proliferative diabetic retinopathy. Anatomic success, as judged by reattachment of the macula, occurred 28 (65%) eyes. Improved visual acuity occurred in 11 (26%) eyes. Severe complications occurring after vitrectomy included moderate to severe rubeosis iridis diabetica (28%), neovascular glaucoma (16%), vitreous hemorrhage (49%), and phthisis bulbi (14%). Eyes that received scatter photocagulation therapy at some time prior to macular detachment had a substantially lower incidence of successful postoperative reattachment of the macula than eyes never treated with photocoagulation.

Scleral buckling procedure for retinal detachments secondary to proliferative diabetic retinopathy

Ninety-two patients (99 eyes) underwent scleral buckling procedures for retinal detachment associated with proliferative diabetic retinopathy. Fifty-three procedures were for rhegmatogenous retinal detachment and 46 for tractional retinal detachment. The average follow-up period was 38 months. Anatomic success was assessed in terms of closure of retinal breaks (59/69, 86%), macular reattachment (42/90, 46%), and reduction in extent of retinal detachment postoperatively as compared to preoperatively (62/99, 63%). The visual acuity was better postoperatively in 33/99 (34%) of the eyes; 58/99 (58%) of the eyes maintained finger counting visual acuity. Improvement in visual acuity was more frequent in eyes with rhegmatogenous detachment (23/53, 43%) than in those with traction detachment (10/46, 22%). Although improvement is generally limited, some patients are markedly benefitted by scleral buckling procedures.

Retinal wrinkling and macular heterotopia in diabetic retinopathy

Retinal wrinkling of the posterior pole was studied in 40 eyes from 31 patients with diabetic retinopathy. Vitreoretinal traction was thought to produce the wrinkling in 32 of the eyes, in 13 of which macular heterotopia also developed, presumably from the same tractional forces. Epiretinal membrane formation was the apparent causal factor producing retinal wrinkling in six eyes and postphotocoagulation chorioretinal scarring in two eyes, in none of which macular heterotopia developed. Retinal wrinkling alone was associated with only mild or no visual acuity loss. Macular heterotopia was associated with more severe loss of visual acuity and with other visual symptoms. Displacement of retinal vessels was an important clue to the diagnosis of macular heterotopia.

A method for recording vitreoretinal relationships

A method for recording vitreoretinal relationships is described. The system includes designations for the extent and height of posterior hyaloid detachment and for sites of abnormal vitreoretinal adhesions. The method may be used for preoperative evaluation of eyes prior to vitrectomy surgery or for the follow-up of patients with vitreoretinal disease.

Retinal branch vessel occlusion in acute intermittent porphyria

Three patients with acute intermittent porphyria were noted to have retinal branch vessel occlusion. Branch "vein" occlusion, segmental optic atrophy, and soft exudate were the most common ocular manifestation. Two patients had labile elevated hypertension. When patients present with retinal branch vessel occlusion and a constellation of bizarre symptoms that might include hypertension, abdominal pain, acute psychotic behavior and/or cutaneous photosensitivity, the diagnosis of acute intermittent porphyria should be considered.

Postvitrectomy keratopathy

Twenty-six of 75 eyes undergoing pars plana vitrectomy developed significant corneal complications requiring treatment. Slow or nonhealing epithelial abrasions, recurrent corneal erosion, and microcystoid and striate keratitis were among the most frequent problems. Significant predisposing factors included diabetes, surgical trauma such as epithelial debridement and prolonged operative time, aphakia, and postoperative glaucoma or hyphema. Corneal complications may be minimized with careful preoperative and operative precautions.

Clinicopathologic correlations in diabetic retinopathy. II. Clinical and histologic appearances of retinal capillary microaneurysms

One eye of a 21-year-old patient with proliferative diabetic retinopathy was available for clinicopathologic correlation. The fluorescent spots in a fluorescein angiogram were correlated with the changes in color fundus photographs and with the corresponding histologic findings in a trypsin digest preparation of the retina. A round, regular fluorescent spot was the most reliable diagnostic indicator of retinal capillary microaneurysms, although some microaneurysms appeared as irregular fluorescent spots, tiny fluorescent spots, or dark silhouettes with or without fluorescent halos. Very large fluorescent spots correlated with very large irregular pouches that may represent intraretinal neovascularization. Fluorescein angiography was considerably more sensitive than color fundus photography for the detection of retinal capillary microaneurysms.

Choroidal neovascular membrane in Best's vitelliform macular dystrophy

The right eye of a 9-year-old white boy with Best's vitelliform macular dystrophy had an intact egg-yolk lesion and a retinal pigment epithelial defect superiorly, suggesting an early pseudohypopyon stage. The disruptive phase of the left eye showed subretinal hemorrhages, a "signet ring," and a subretinal neovascular membrane.

Retinal ischemia in diabetic retinopathy

Eight patients with proliferative diabetic retinopathy developed extensive retinal arteriolar and capillary obstruction. Ophthalmoscopy showed many white, thread-like retinal arterioles associated with capillary and venous dilatation. Widespread retinal arteriolar and capillary nonperfusion was demonstrated by fluorescein angiography. Ischemic maculopathy resulted in severe loss of visual acuity in some eyes. The severe degree of retinal ischemia was accompanied by optic disc pallor and neovascularization and a high incidence of rubeosis iridis with neovascular glaucoma. Patients with this variety of diabetic retinopathy have a poor prognosis of retaining useful vision.