The contribution of non-mydriatic fundus photography in the detection of diabetic retinopathy before and after dilatation of the pupils in black diabetics was investigated and compared with direct ophthalmoscopy. Eighty-six patients were examined and good-quality photographs were obtained for 54,7% of eyes before and 86,6% of eyes after dilatation. Photographically documented retinopathy was detected by ophthalmoscopy in only 64,7% of eyes. The two methods were concordant for the presence of retinopathy in 62,2% of eyes before and 56,9% of eyes after dilatation. Photography through dilated pupils also i.mproved the rate of detection of diabetic retinopathy from 24% to 30%. The 45° non-mydriatic fundus camera was found to be a valuable adjunct in the detection of diabetic retinopathy in a busy diabetic clinic

Mollentze, W. F.

Steyn, A.F.

Stulting, A. A.

English

AJOL - African Journals Online

248 SAMJ VOL 78 1 SEPT 1990Ophthalmoscopy versus non-mydriatic fundusphotography in the detection of diabeticretinopathy in black patientsW. F. MOLLENTZE, A. A. STULTING, A. F. STEYNSummaryThe contribution of non-mydriatic fundus Photogr~phY in thedetection of diabetic retinopathy before and after dilatation ofth~ pU~i1s in black diabetics was investigated and comparedwith direct ophthalmoscopy. Eighty-six patients wereexamined and good-quality photographs were obtained for54,7% of eyes before and 86,6% of eyes after dilatation.Photographically documented retinopathy was detected byophthalmoscopy in only 64,7% of eyes. The two methodswere concordant for the presence of retinopathy in 62,2% ofeyes before and 56,9% of eyes after dilatation. Photographythrough dilated pupils also i.mproved the rate of detection ofdiabetic retinopathy from 24% to 30%. The 45° non-mydriaticfundus camera was found to be a valuable adjunct in thedetection of diabetic retinopathy in a busy diabetic clinic.S Air Med J 1990; 78: 248-250.Diabetic eye disease is a leading cause of blindness in theWestern world today, with diabetic retinopathy responsible for70% of cases of diabetic blindness.! Photocoagulation treat-ment has been shown to be effective in preserving vision ineyes with proliferative retinopathy as well as diabetic macu-lopathy.2,3 The prevalence of diabetic retinopathy was found tobe ~6,7% ~ a large diabetic clinic, with 9,5% of patients havings~nou~ ret.m.opathy.4 Screening for diabetic retinopathy in anydiabetIc clinic should therefore be a maner of priority.Res~onsi?ili~ .for screening for diabetic retinopathy in abusy d.labetlc clinic such as our own often rests solely upon theanendmg doctors. Frequently they are inexperienced and notpermanent members of the diabetic team. Furthermore theability of non-ophthalmologists to identify serious diabeticretinopathy has been questioned.5 .Several studies have demonsttated the usefulness of a 45°non-mydriatic fundus camera in the detection of diabeticretinopathy through an undilated pupil.6- 8 A major drawbackof this technique is the fact that the camera covers a field of45° and only the posterior pole of the retina is visualised. Thisincludes the optic disc, the macula, the central retina justtemporal to the macula and both the lower and the uppertemporal vessels (Fig. 1). The possibility that the camera canmiss serious peripheral retinopathy has been pointed out.9 Afurther disadvantage of non-mydriatic fundus photography isthe high rate of poor-quality photographs.7This study was undenaken to evaluate non-mydriatic fundusphotography as a means of detecting diabetic retinopathy inblack patients, whose retinas are more heavily pigmented thanthose of whites. A further objective was to compare the abilityDepartments of Internal Medicine and OphthalmologyUniversity of the Orange Free State, Bloemfontein, OFS 'W. F. MOLLENTZE, M.MED. (11\7.), F.C.P. (S.A.)A. A. STULTING, M.MED (OPHTH.)A. F. STEYN, M.MED.(INT.)Fig..1. Example of a ~o.lour photograph of the right fundus asobtained by non-mydnatic fundus photography. . .of our medical staff to detect diabetic retinopathy with that ofthe camera. The fmal objective was to ascertain the role ofphotography through a dilated pupil in an effort to improvethe quality of photographs. .Patients and methodsPelonomi Hospital is a 1 200-bed teaching hospital, and 90 -100 patients a week are seen at the diabetic clinic. The clinic isstaffed by 1 consultant physician, 2 registrars, 1 medicalofficer, 2 interns and 2 fmal-year medical students. Patientsincluded in this study were on our routine screening pro-gramme for long-term complications. Each week the first 9-10patients who had had diabetes for more than 5 years wereselected. Patients who had undergone previous eye surgerywere excluded.Direct ophthalmoscopy was performed through undilatedand dilated pupils in a darkened room and no time limit wasset to the ophthalmoscopists. A modified World HealthOrg~isationscoring system was used to document the degreeof retInopathy as seen at the posterior pole of the retina thatcorresponded to the photograph obtained, on a schematicchart. 10 Lesions seen outside this area could also·be recorded.Non-mydriatic fundus photography was performed in adarkened room by the official hospital photographer using theCanon CR4-45NM retinal camera with a Polaroid frlm back.Only one exposure of each eye was permined regardless of thequality of the photograph before and after dilatation of theSAMJ VOL 78 1 SEPT 1990 249pupil. Even if a cataract was present an anempt was made toobtain a photograph. A waiting period after the flash forpatients with undilated pupils was allowed so that the othereye could recover from the flash before photography. Thephotographs were graded with the naked eye by an independentobserver (A. A. S.) and the results recorded in a similar way "-on a chart similar to that used to record results of ophthalmo-scopy. The observer was unaware of the results of fundoscopy.The quality of the photographs was recorded as 'good' onlywhen the whole area of interest was visible and sharplyfocused. When part of the photograph was obscured by a darkarea or ring of light at the periphery or when it was out offocus, it was regarded as of 'poor' quality. The photographswere graded as 'unusable' when no retinal detail could be seen.ResultsEighty-six patients, mostly with non-insulin-dependent dia-betes, were examined. The average duration of diabetes was9,5 years (range 5 - 26 years).The number of good photographs obtained was 94 (54,7%)before and 149 (86,6%) after dilatation (Table I).Table II compares the severity of retinopathy according todirect ophthalmoscopy and non-mydriatic photography.Retinopathy was detected by ophthalmoscopy in 43 eyes (34 +9) (25%) before and 70 eyes (50 + 20) (40,7%) after dilatation.The corresponding figures for the camera were 42 eyes (41 +1) (24,4%) and 51 eyes (49 + 2) (29,7%), respectively. Agree-ment between ophthalmoscopy and the camera with regard tothe presence or absence of diabetic retinopathy was reached in107 eyes (62,2%) before and 98 eyes (56,9%) after dilatation.Diabetic retinopathy was detected in 51 of 172 photographs(29,7%) obtained through dilated pupils (Fig. 2). In only 33(20 + 11 + 2) of these (64,7%) was retinopathy detected byophthalmoscopy. Diabetic retinopathy was missed on ophthal-moscopy in 18 eyes.DiscussionThe somewhat more heavily pigmented retinas of black patientsposed no problems and it was possible to obtain photographsFig. 2. Colour photograph of the right fundus obtained through adilated pupil showing background retinopathy and laser spots.of acceptable quality in the majority of cases. The proportionof good photographs obtained before dilatation (54,7%) com-pared favourably with the figure of 41% reported by Ryder era/.7 However, dilatation of the pupil improved the number ofgood photographs by 31,9% (from 54,7% to 86,6%) (Table I).This dramatic improvement in the quality of photographs is ofmajor importance, since the Polaroid fIlms constitute the bulkof the running costs of the system. More important, thedetection rate for retinopathy was also increased from 24% to30% after dilatation (Table I1). Photography through dilatedpupils is also less time-consuming and taxing for both operatorand patient. Photography through a dilated pupil was welltolerated. According to Klein er al.,6 no association was foundbetween dilatation of the pupil and subjective discomfort withthe flash.TABLE I. RATING OF THE QUALITY OF POLAROID PHOTOGRAPHS BEFORE AND AFTER DILATATIONOF THE PUPILTotal No. of photographsUnusable Poor Good takenNo. % No. % No. %Before dilatation 17 9,9 61 35,5 94 54,7 172After dilatation 6 3,5 17 9,9 149 86,6 172TABLE 11. COMPARISON OF SEVERITY OF RETINOPATHY BY DIRECT OPHTHALMOSCOPY AND 45° CAMERABEFORE AND AFTER DILATATION OF THE PUPIL45°cameraNon-proliferative ProliferativeNo retinopathy retinopathy retinopathy Cannot determine TotalOphthalmoscopy Bet. After Bet. After Bet. After Bef. After Bet. AfterNo retinopathy 82 71 16 18 0 0 11 1 109 90Non-proliferative retinopathy 16 30 17 20 0 0 1 0 34 50Proliferative retinopathy 5 7 3 11 1 2 0 0 9 20Cannot determine 8 7 5 0 0 0 7 5 20 12--Total 111 115 41 49 1 2 19 6 172 172Bel. =before dilatation; After =after dilatation.250 SAMJ VOL 78 1 SEPT 1990Agreement between ophthalmoscopy and photography wasnot substantially altered by the status of the pupils, as isevident from the figures of 107 eyes (62,2%) and 98 eyes(56,9%) before and after dilatation, respectively. However, thedetection rate for retinopathy by ophthalmoscopy throughdilated pupils was only 64,7% of that of the camera. This is inline with the results reponed by others.5•7In 37 eyes (21,5%) diabetic retinopathy that could not besubstantiated from the photographs was detected by ophthalmo-scopy through dIlated pupils. It is possible that the lesionsobserved fell outside the field of photography, although theywere documented to be confined to the posterior pole of theretina. Although we are of the opinion that diabetic retinopathywas grossly overdiagnosed by ophthalmoscopy after dilatationof the pupils, these patients must still be referred for fullophthalmological assessment.Rosen et al. 11 found it difficult for patients to follow boththe external and the internal fixation lamps of the non-mydriatic camera, a problem that we did not encounter withthe CR445NM camera. The same authors also criticised non-mydriatic fundus photography on the grounds that it didnot detect peripheral retinal ischaemia, peripheral intraretinalmicro-angiopathy, or even macular oedema. However, thesame applies to most other fundus cameras when fluoresceinangiography is not performed:In conclusion, we found the CR4-45NM camera easy tooperate and no photographs were lost due to malfunction. Wealso found photography through a dilated pupil to be superiorto non-mydriatic fundus photography. The camera proveditself valuable in conjunction with ophthalmoscopy as a meansof screening for diabetic retinopathy under our clinic circum-stances. In addition to providing permanent records of apatient's retina, the camera also provides excellent material forstudent education.We are indebted to Mr R. Taylor for taking the photographsand to the Staff and patients of the diabetic clinic for their co-operation.REFERENCES1. Little HL, Jack RL, Pau A, Forsham PH. Diabecic Rerinopalhy. New York:Thieme-Stranon, 1983: 17.2. The Diabetic Retinopathy Study Research Group. Photocoagulation treat-ment of proliferative diabetic retinopathy: the second repon of diabeticretinopathy study findings. OphlhaImology 1978; 8S: 82-10S.3. British Multicenter Study Group. Photocoagulation for diabetic macula-pathy. Diabetes 1983; 32: 1010-1016.4. Scohie IN, MacCuish AC, Barrie T, Green FD, Foulds WS. Seriousretinopathy in a diabetic clinic: prevalence and therapeutic implications.Lancet 1981; 2: 520-521.5. Sussman EJ, Tsiaras WG, Soper KA. Diagnosis of diabetic eye' disease.JAMA 1982; 247: 3231-3234.6. Klein R, Klein BEK, Neider MW et al. Diabetic retinopathy as detectedusing ophthalmoscopy, a nonmydriatic camera and a standard fundus camera.Ophthalmology 1985; 92: 485-491.7. Ryder REJ, Vora JP, Atiea JA et al. Possible new method to improvedetection of diabetic retinopathy: polaroid non-mydriatic retinal photography.Br MedJ 1985; 291: 1256-1257.8. Williams R, Nussey $, Humphry R, Thomson G. Assessment of non-mydriatic fundus photography in detection of diabetic retinopathy. Br MedJ1986; 293: 1140-1142. .9. Barrie T, MacCuish AC. Assessment of non-mydriatic fundus photograhy indetection of diabetic retinopathy (Letter). Br MedJ 1986; 293: 1304-1305.10. Diabetes Drafting Group, World Health Organisation Multinational Studyof Vascular Disease in Diabetics. Prevalence of small vessel and large vesseldisease in diabetic patients from 14 centers. Diabetologia 1985; 25: 615-640.11. .Rosen ES, Raines M, Hancock R. Use of non-mydriatic cameras to screendiabetic patients for retinopathy. Semin Ophthalmol1987; 2: 37-44.Results of laser treatment for sub-retinalneovascular membranesM. J. N. CARTER, A. A. STULTINGSummaryA retrospective study was carried out to determine the resultsof laser treatment for choroidal neovascular membranes inage-related macular degeneration in 92 patients in whomfluorescein angiography was performed for this conditionover a 7-year period. Twenty-nine of these patients, treatedwith the argon laser, were followed up regularly for 15 months.The treatment comprised overlapping laser spots of 200 J.Lmand an average power of 390 mW. The results of this studydemonstrated that: (i) the majority of membranes were closer·than 500 J.Lm from the foveola; (ii) the second eye involvementrate in the same patient was 15,79% over 15 months; and (iii)a 37,5% significant visual' loss or 41% two lines or greatervisual loss was seen after 15 months, which comparesfavourably with results of laser treatment reported by otherinstitutions.S Atr Med J 1990; 78: 250-253.Department of Ophthalmology, University of the OrangeFree State, Bloemfontein, OFSM. J. N. CARTER, M.MED. (OPHTH.), F.e.S.(S.A.)A. A. STULTING, M.MED. (OPHTH.), F.e. OPHTH. (S.A.)Age-related macular degeneration with subsequent neovascularmembrane formation is a major cause of blindness in patientsin the 6th and 7th decades of life.Neovascularisation results from invasion of the sub-retinalpigment epithelial space by vessels originating in the chorio-capillaris. I•2 The new vessels grow under the retinal pigmentepithelium through breaks caused by degenerative changes inBruch's membrane. 2 It has been suggested that the neovascularmembrane may cause the break and not vice versa. 3Symptoms occur when the macula is affected by serous orhaemonhagic detachment of the retinal pigment epitheliumand sensory· retina produced by exudation from these newvessels. I-l This exudative and sometimes haemorrhagic processoften leads to severe and permanent loss of central visionbecause of sub-retinal fibrovascular organisation.2 Progressivefunctional deterioration has been reponed in the natural courseof neovascular membranes. The Macular PhotocoagulationStudy Group in the USA has demonstrated the definitebenefits of laser photocoagulation in the treatment of choroidalneovascular membranes and has advised treatment of choroidalnew vessels located 200 J.Lm or more from the centre of thefoveal avascular zone.3-7 In their study, severe visual loss waspostponed for ,18 months.

Ophthalmoscopy versus non-mydriatic fundus photography in the detection of diabetic retinopathy in black patients

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Ophthalmoscopy versus non-mydriatic fundus photography in the detection of diabetic retinopathy in black patients

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