354 AMERICAN JOURNAL OF OPHTHALMOLOGY August, 1985

_______ Reply _

EDITOR:I appreciate Dr. Girard's comments on my

article. I agree with him in that the differen­tial diagnosis of Brown-McLean syndromeshould include Fuchs' endothelial dystrophy.As I said in my article, it may be that thesyndrome may be caused by a subclinical en­dothelial dystrophy that is decompensated byiridodonesis and endophthalmodonesis inaphakic eyes. However, I think that theBrown-McLean syndrome and Fuchs' dystro­phy are different conditions because of thefollowing:

The Brown-Mckean syndrome may be ob­served in patients of any age, even youngpeople, after some years of aphakia or pseu­dophakia of any kind. I have not observedthe syndrome in phakic patients although Ionce suspected it in a myopic middle-agedwoman.

In my experience, the Brown-McLean syn­drome never involves the center of the corneaand very seldom evolves with cornea guttata.

After a three-year stay in the United Stateson ophthalmic fellowships in different places,I came to the conviction that Fuchs' endothe­lial dystrophy is much more common there,perhaps because of racial factors, than inChile. In Chile Fuchs' dystrophy is a rare con­dition, but the Brown-Mcl.ean syndrome hasbeen diagnosed much more often sinceQuintana and I reported the first cases in theChilean ophthalmic Iiterature.!

The Brown-Mcl.ean syndrome almost al­ways evolves with a peculiar orange punctatepigmentation on the endothelium of theedematous areas of the cornea. I am notaware of any such finding in Fuchs' dystro­phy.

In my experience, the Brown-McLean syn­drome occurs with equal frequency in bothsexes, but it is more common in aphakic my­opic eyes, probably because of a more pro­nounced endophthalmodonesis.

RAIMUNDO CHARLIN, M.D.. Santiago, Chile

Reference

1. CharIin, R., and Quintano, R.: Edema cornealperiferico post facoeresis. Sindrome de Brown­McLean. Arch. Chilenos Of talmoI. 37:17, 1980.

Momentary Fluctuations of IntraocularPressure in Normal and Glaucomatous

EyesEDITOR:

In the article, "Momentary fluctuations ofintraocular pressure in normal and glaucoma­tous eyes" (Am. J. Ophthalmol. 99:333, March1985), J. R. Piltz, R. Starita, M. Miron, and P.Henkind reported a greater mean range ofintraocular pressure readings in glaucomatouseyes (4.4 mm Hg) than in normal eyes(2.7 mm Hg), and a positive correlation be­tween mean intraocular pressure and meanrange of intraocular pressure for glaucoma­tous eyes but not in normal eyes.

This study agreed with that of Perkins' whoalso showed greater ranges of intraocularpressure in glaucomatous eyes. We questionwhether such information can be correlated toglaucoma and its pathogenesis without alsoconsidering certain cardiovascular features,including autoregulation.

Because about 85% of the total ocular bloodflow is to the choroid, it is believed that cho­roidal blood flow generates the intraocularpulse wave or ocular pulse.! The similaritiesin shape that exist between the systemic arte­rial pulse wave and intraocular pulse wave,"as well as specific changes in the ocular pulsewith alterations in respiration, 1 blood pres­sure." heart rate, and posture, indicate theclose relationship between the ocular pulseand the cardiovascular system.

To'mey and associates! found evidence tosupport a positive correlation between meanintraocular pressure and mean range of intra­ocular pressure in normals. They reportedfinding higher amplitudes with higher intra­ocular pressures in normal controls. The lowmean pressure (11.9 mm Hg) in the 18 nor­mals described by Piltz and associates maynot have provided an adequate stimulus foractivation of the autoregulatory function be­lieved to exist in the eye." Normal eyes, there­fore, are sensitive to changes in intraocularvolume but may require an appropriate intra­ocular pressure challenge to activate the auto­regulatory forces in the choroidal bed. Con­versely, eyes with ocular hypertension andthose with early glaucoma may demonstrate apositive correlation between mean intraocularpressure and range of intraocular pressure byvirtue of intact autoregulation despite highermean intraocular pressure and higher meandiurnal intraocular pressure variations.