Eye (1988) 2,547-551

The Blood-Retinal Barrier in Angioid Streaks

R. BROWNI and M. F. RAINES2

Manchester

Summary The blood retinal barrier was investigated in a group of patients with angioid streaks and , using the technique of vitreous fluorophotometry. Angioid streaks are breaks in the elastic layer of Bruch's membrane with atrophy of the adjacent pigment epithelium. The retinal pigment epithelial cells and their intercellular junctions form part of the blood retinal barrier. In this study it was found that despite the presence of' angioid streaks and extensive areas of pigment epithelial atrophy the blood retinal barrier was intact. In contrast, when disciform degeneration had occurred the blood retinal barrier was abnormal. It is proposed that vitreous fluorophotometry could be used to identify those patients developing disciform degeneration at an early and therefore potentially treatable stage.

Angioid streaks are ophthalmoscopically visi­ epithelium overlying the defects in Bruch's ble red-brown streaks that radiate from the membrane in patients with angioid streaks is peripapillary area of the fundus. They are atrophic, it may be expected that the BRB in often associated with pseudoxanthoma elas­ these areas will be abnormal. ticum, a generalised disturbance of elastic tis­ Vitreous fluorophotometry is a sensitive. sue throughout the body. 1,2 reproducible and quantitative method of The important complications of angioid detecting abnormalities in the BRB.y,1II streaks are subretinal neovascularisation and We undertook to study the blood-retinal choroidal haemorrhage, either of which may barrier in a group of patients with angioid present clinically with disturbance or loss of streaks, by the technique of vitreous vision. }.) fluorophotometry, and to comment on its Angioid streaks represent breaks in the application in the clinical setting. elastic layer of Bruch's membrane accom­ panied by varying degrees of disturbance and atrophy of the overlying retinal pigment Patients and Methods epithelium.6 Patients with angioid streaks were selected The retinal pigment epithelial cells and from the diagnostic index of our retinal their junctions form part of the blood-retinal photography department. Of these patients, barrier (BRB).H When this barrier is dis­ seven agreed to take part in this study. Three turbed there is a potential for choroidal of these seven were members of the same extra-cellular fluid to pass into the neuro­ family. The opportunity was taken to and vitreous. Since the pigment examine another three members of this

Correspondence to: Mr. R. Brown, Retinal Photography Department, Manchester Royal Hospital, Oxford Road, Manchester. M13 9WH.

Presented at the Annual Congress of the Ophthalmological Society of the United Kingdom, April 1988.

IFrom Manchester Royal Eye Hospital, Oxford Road, Manchester, M13 9WH. England. 2Birmingham .and Midland Eye Hospital, Church Street, Birmingham, B3 2NS. England. 548 R. BROWN AND M, F. RAINES family (see pedigree). In total therefore, ten termed the measurement scan, was per­ patients were investigated. formed at 60 minute post fluorescein injec­ All patients with angioid streaks in this tion. Two samples of venous blood were study showed the skin changes of pseudoxan­ obtained from each patient. The first taken thoma elasticum. Informed written consent between 5 and 10 minutes, the other at 60 was obtained from all patients. minutes post injection. The exact times of the The ocular examination consisted of ; vis­ scans and the venepunctures were recorded. ual acuity as measured by Snellen chart, slit The plasma fluorescein values were entered lamp examination of the anterior segments, into a computer algorithm to obtain the direct and indirect ophthalmoscopy of the plasma fluorescein integral. A posterior vit­ vitreous and retina, colour fundus photo­ reous penetration ratio (PR) was calculated graphy, and vitreous using the scans and plasma data.!3 This fluorophotometry. penetration ratio is a measurement of the None of the patients had any other ocular integrity of the blood retinal barrier. or systemic conditions known to influence To establish a normal range, twenty five f1uorophotometric measurements. age and sex matched normal individuals (30 Fundal examination and fluorescein ) also underwent vitreous f1uoro­ studies were performed following pupil photometry according to the above method. dilataton which was achieved by the instilla­ tion of topical Tropicamide 1 % and Phenylephrine 10%. Vitreous f1uorophoto­ Results metry was performed using the Fluorotron The pedigree of the family examined is Master™ (Coherent, Palo Alto, California). shown in Figure 1. The parents, generation The technique has been described in detail A, were not examined and were reported by elsewhere11.12 and will be briefly reviewed family members not to have any known ocu­ here. Initial fluorotron scans, termed the lar problems. No consanguinity has been background scans, were obtained from each known in the family. eye. These background scans measure the The Table shows the examination findings natural fluorescence of the ocular tissues. A of each patient. In a total of six eyes angioid bolus of sodium fluorescein (14 mg/kg body streaks were present without neovascularisa­ weight) was then injected intravenously. tion or disciform scar (Fig. 2). In all these Standard fluorescein angiography was per­ eyes the posterior vitreous penetration ratio formed. Between 3 and 5 minutes post injec­ was within normal limits. Eight eyes showed tion, a further scan termed the bolus scan was angioid streaks with sub retinal neovasculari­ performed. The bolus scan is used in the final sation or disciform scar (Fig. 3). In all these calculation to minimise the influence of eyes the penetration ratio was elevated above chorioretinal fluorescence on the vitreoLls the normal range. fluorescence measurement. A final scan, The six eyes without angioid streaks all had a normal penetration ratio. The twenty five A normal individuals studied had a penetration ratio of 2.35±O.76xlO-6/min (mean +/­ S.D.).This value is similar to previously pub­ lished normal ranges which used the same method of analysis.!3 C 1

o = Mele, Not Affected Discussion • = Mele, Affected This study has shown that patients with 0= Femele, Not Affected uncomplicated angioid streaks and pseudo­ • = Femele. Affected xanthoma elasticum have a normal posterior Fig, L Pedigree of family studied with vitreous penetration ratio. To our knowledge Pseudoxanthoma Elasticum. this finding has not previously been reported. THE BLOOD-RETINAL BARRIER IN ANGIOID STREAKS 549

Table

P. Ratio Patient Sex Age Eye VIA Ophthalmoscopyl FFA xlO-6/min

Bl M 38 R: CF Extensive angioid streaks 23.743 L: CF and bilateral macular 17.628 disciform degeneration.

B2 F 37 R: 6/24 Angioid streaks and macular 6.138 disciform scar L: 6/6 Angioid streaks and peripheral 1.619 pigmentary disturbance.

B3 F 36 R: 6/6 Normal. No angioid streaks 1.539 L: 6/6 Normal 1.148

84 F 34 R: 6/5 Angioid streaks 2.789 L: 6/9 Extensive angioid streaks 2.627

B5 F 27 R: 6/6 Normal. No angioid streaks 2.538

L: 6/6 Normal 1 . 629

C7 M 14 R: 6/5 Normal. No angioid streaks 1.971 L: 6/5 Normal 1.863

F 28 R: 1/60 Angioid streaks and macular 7.514 disciform degeneration L: 6/6 Angioid streaks 1.711

2 M 49 R: 6/36 Bilateral angioid streaks and 4.617 L: CF macular disciform scars 6.754

3 M 45 R: 6/5 Angioid streaks 1.940 L: 6/5 Angioid streah 1.80S

4 F 52 R: 6/6 Bilateral angioid streaks with 8.354 marked macular pigmentary L: 6/9 disturbance amd peripheral 10.967 SRNV.

Patients B I to ('7 were all members of the family investigated. (see Pedigree). The other patients examined arc numbered I to 4. VI A= ViSlla/ Acuity as measured br Snellen charI. CF=CounttinKers at / metre. FFA = Fundus fluorescein angiogram. /'.Ratio= Penelratiofl Rmio (Normal rangc=2.35 ±O. 76x/I)-I'llnin)

SRNV = Subretinal neovascularislltioll.

The blood-retinal barrier therefore blood-retinal barrier. The normal members appears to be functionally intact in these of the family studied also had penetration patients despite the presence of breaks in ratios within the normal range. Bruch's membrane and accompanying In those patients with associated disciform atrophy of the adjacent pigment epithelium. degeneration however, the blood-retinal bar­ This finding is surprising since the pigment rier is markedly abnormal in all cases. This epithelium is regarded as forming part of the reflects the disturbance in the BRB that 550 R. BROWN AND M. F. RAINES

Fig. 2: Patient B4. Left Eye. Fluorescein angiog­ Fig. 3. Patient B2. Right Eye. Fluorescein ram. arterial phase. Showing hyperfluorescence of angiogram, late phase. Showing hyperfluorescence the angioid streaks. of the angioid streaks and extensive disciform scar­ ring. occurs when subretinal new vessels are pre­ 2 Hogan JF, Heaton CL: Angioid streaks and sys­ sent. A similar breakdown of the BRB has temic disease. Br J Dermatol 1973; 89: 411 - been shown previously by a study in which 16. 3 Shilling JS, Blach RK: Prognosis and therapy of four patients with age related macular degen­ angioid streaks. Trans Ophthalmol Soc UK eration and subretinal neovascularisation all 1975; 95: 301-6. had elevated penetration ratios.14 Sub-retinal 4 Hilton GF: Late serosanguineous detachment neovascularisation, occurring in patients with of the macula after traumatic choroidal rup­ angioid streaks, often affects the macular ture. Am J Ophthalmol1975; 79: 997-. area, resulting in a severe loss of form vision. 5 Hagedoorn A: Angioid streaks and traumatic The results of treatment are often disappoint­ ruptures of Bruchs membrane. Br J Ophthal­ ing. Early treatment may potentially improve mol 1975; 59: 267-. the visual prognosis, although early subreti­ 6 Green WR: of angioid streaks. In nal neovascularisation in association with an Spencer WH cd.: Ophthalmic Pathology. An atlas and textbook. Philadelphia: WB Saun­ angioid streak may be difficult to detect. ders. 1985: Vol 2: 1023-1032. Fluorescein angiography may not be helpful 7 Shiose Y: Electron Microscope Studies on as new vessel hyperfluorescence may be Blood Retinal and Blood Aqueous Barriers. superimposed over the pigment epithelial Jpn J Ophthalmol1970; 14: 73-. defect. H Shakib M, Cunha-Vaz JG: Studies on the Per­ In conclusion, breakdown of the BRB can meability of the Blood Retinal Barrier. IV. be demonstrated by vitreous fluorophoto­ Junctional Complexes of the Retinal Vessels metry, and as it appears that this breakdown and their role in the Permeability of the Blood occurs with angioid streaks only when sub­ Retinal Barrier. Exp Eye Res 1966, 5: 229-. 9 retinal new vessels are present, it may be pos­ Cunha-Vaz JG, Faria Dc Abreu JR, Campos AJ et al: Early Breakdown of the Blood Reti­ sible to use vitreous fluorophotometry to nal Barrier in Diabetes. Br J Ophthalmol identify those patients developing new ves­ 1975; 59: 64 9- 56. sels at an early and potentially treatable III Waltman SR, Oestrich CA, Krupin T, Hanish stage. S, Ratzan S, Santiago J, Kilo C: Quantitative Vitreous Fluorophometry. A Sensitive References Technique for Measuring Early Breakdown of 1 Shields JA, Federman JL, Tomer TL, Annesley the Blood Retinal Barrier in Young Diabetic WH: Angioid streaks 1. Ophthalmoscopic Patients. Diabetes 1978; 27: 85-. variations and diagnostic problems. Br J 11 Zeimer RC, Blair NP, Cunha-Vaz JG: Vitreous Ophthalmol1975; 59: 257-66. Fluorophotometry for Clinical Research. 1. THE BLOOD-RETINAL BARRIER IN ANGIOID STREAKS 551

Description and Evaluation of a new MC, Ishimota BM, Leite E: Characterization Fluorophometer. Arch Ophthalmol 1983; 101: of the Early Stages of Diabetic Retinopathy 1753-6. by Vitreous Fluorophotometry. Diabetes 12 Zeimer RC, Blair NP, Cunha-Vaz JG: Vitreous 1985; 34: 53-9. Fluorophotometry for Clinical Research. 1l. 14 Merin S, Blair NP, Tso MOM: Vitreous Method of Data Acquisition and Processing. Fluorophotometry in Patients with Senile Arch Ophthalmol 1983; 101: 1757-61. Macular Degeneration. Invest Ophthalmol Vis 13 Cunha-Vaz JG, Gray JR, Zeimer RC, Mota Sci 1987; 28: 756-9.