The pathogenesis of corneal arcus formation in the cholesterol-fed rabbit and in man: K. W. Walton...

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th roughou t the heal~ug period, but!virgh~ silk exci ted more tissue reaction and wa~ accompanied by epithelial downg:uwi;h.

Optic Disc .&ngloma

K. Rv-BrSST~t~" ~ ' D J . A. OOSTERI'ILrIs, Birmin4flu~m & Midla~ut 1~!/e Ho,~pital and UniverMgy ~'~.1e C'linie, Leide~

Pre l iminarY E x p e r i m e n t s on H e a l i n g o f Corneal I n j u r i e s

D. F. CoLE .~rD P. K . LEAV]~, Departme~g of Physlolog~j and Bioch~.mi~try, I~.stitut¢ of Ophthal. molocyy, London

It, was t hough t t h a t a s t u d y of pressure-decay curve~ af ter corneal injurY would provide a mean~ of following the process of repair and a series o f pilot exper iments lu~ been carried out using adul t albino rats .

Standardized 2 m m incisions were made in one cornea. At intervals of 0, 2, 4, 8, 14 and 21 d~ys later the animals w¢~re killed and the eye connected to a pressure t ransducer and reservoir. The presst~re in the eye was raised to a pre .de termined level and the rate o f pressure decay ("pressure-dropping curve") recorded using a Sanborn r e ~ r d i n g sys tem. Pressure-dropphag curves were ob ta ined f rom s tar t ing pressures o f 30 up to 200 mmHg, and the ra te constants in each case es t imated f rom semi..logarithmic plots.

The ra te cons tan t for the inci~ed eyes were raised in the 2 and 4 d a y groups but had re turned to normal by 8 days. There was no maasive leakage even in the 2-day group and the increased rate for pressure dec~y is ascribed to seepage a t the site o f injury. In control and healed corneas the ra te constant was the same over the rauge o f s ta r t ing pressures used bu t 2 days af ter in ju ry the ra te-cons tant was marked ly increased a t the higher s tar t ing pressures. This m a y be due to mechanical r~tretching o f the replacement tissue.

Pi lot Study o f O x y p h e n b u t a z o n e (Tanderi l ) Ointment

H. V ~ o , ~ S~rrrH, Bir~nir~ham and Midland Eye Hob'pital

T h e PathogenesL~ o f Corneal Arcus F o r m a t i o n in t he Choles tero l - fed Rabbit and in M a n

K. "W. ~,V.a.r,To~" x_~-D D. J . DITNKERLEX', Department of Ex'l~erimengal Pa~holo,yy, University of B ir~in,£ham

The deposition of lipid in the cornea and cil iary boTAy is broadly correlated with the development of atherosclerosis in humans . A somewhat similar process also occurs in rabbi ts mainta ined on cholesterol- or l ip id-supplemented diets. The pathogenesis of lipid deposi t ion in the eye in both species has been s tudied using immunological methods . I t has been establ ished t h a t in each case the p redominan t form in which the lipid is deposi ted is as plasma low-densi ty (beta) lipoprotein. This protein has previously been shown to be sin~iLarly involved in the fo rma t ion of uncomplicated atherosclerotie lesions in ar ter ie~

The vessel~ o f t he ~ a n d c ~ a r y body have 1~, mfliar F~rmeabil i ty characteristic~ in t h a t t h e y are concerned in producing the protein-rich ul t raf i l t ra te o f the anter ior chamber (aqueous humour) . I n parallel with observat ion of the morphologiCalchanges t h a t occur wi th Hpid deposit ion in the s t ruc tures o f the eye, quan t i t a t i ve and qual i ta t ive Ghanges have been observed in the composit ion o f the aqueous humour . The rela t ion of these changes to the mechanism o f lipid deposit ion in the eye will be discussed a n d c o n t r i v e d wi th pos tu la ted mechanism of ar ter ial atherogenesis.

A Study o f Vasoact lve D r u g s in the R e t i n a l C i rcu la t ion o f an E x t r a c o r p o r e a l P e r f u s e d E y e

R. l~,l~olrva.r~T A~,q) C. l~rvA, Cochin Medir, aJ ~chool, 27 R~ze du Faubourg St-Jac, ffuea, Paris 14 e Fram~

Because o f a generalized react ion in t he organism the behax~iour of the re t ina l vea~els in pharma- colog~caI exper imenta is d i ~ c u l t to evaluate . Fo r instance, Thuransk-y observed t h a t adrenal/he