Documenta Ophthalmologica 46,2: 207-213, 1979

IATROGENIC ENDOTHELIAL DAMAGE

DURING CATARACT EXTRACTION

H.J.M. V/3LKER-DIEBEN, C.C. KOK-VAN ALPHEN & E.R. BARTHEN (Leyden)

Key words: Corneal endothelium, Cataract surgery.

ABSTRACT

Morphological changes in the endothelium of rabbits' corneas after rinsing with Ringer's solution, chymotrase 0.05% or acetylcholine could not be demonstrated by vital staining with nitroblue tetrazolium.

Local lesions caused by manipulations in the anterior chamber were conspicuous. Endothelial lesions due to manipulations with an intra-ocular lens were studied in

the same way.

INTRODUCTION

To become more aware of the possible iatrogenic endothelial damage

occurring during cataract extraction, some series of experiments were

performed on rabbits, in which one part of a cataract extraction was carried

out on the left eye of the experimental animal, while the right eye served as

control. Table 1 gives particulars about the number of rabbits per series of

tests and the part of the cataract operation which was being studied.

MATERIAL AND METHODS

For the first two series of tests chinchilla rabbits were used weighing 2 - 3

Kg. For the other series random animals were used of varying weights and

ages.

All the steps were performed as carefully as possible under the operation

microscope and an exact report of each case was made in which special

difficulties or anything unusual were noted.

After the animal had been killed with an overdose of thiopental

(Pentothal) sodium, the anterior chamber was opened with a small incision

at the limbus. Through a fine anterior chamber cannula in this incision the

chamber was then rinsed out for 5 minutes continuously with Ringer's

solution obtained from ampoules. Directly afterwards the eye was enuclea-

ted and the cornea freed via a scleral incision in the same way as the cornea

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Table 1. Survey of tests performed on rabbits' eyes.

Number OS OD

5 min. Ringer 20 ~

5 min. Ringer 35 ~

2 min. 2cc Chymotripsine 0,05%, 5cc Ringer 20 ~

2cc Acetylcholine

Worst-lens, weight 0,015 gram

5cc Ringer 20 ~

Binkhorst-lens

weight 0,02 gr

of a donor eye for corneal transplantations. Great care was taken that the

anterior chamber did not empty during these steps. The chamber angle was

then pulled free, after which the cornea was placed on a Teflon punchblock

and four 6 mm trephine specimens were punched out. These were stained

with nitroblue tetrazolium, an enzyme stain with which only living

endothelial cells stain blue.

The most important result of these first two series was that this

experimental set-up produced no evidence of abnormalities on the cellular

level. Neither did cell-counts per unit of surface area reveal any significant

difference between the eye which had been rinsed with Ringer's solution

and the control eye.

Several 6 mm trephine specimens from the left and right eyes were

cultivated by Dr. Dandrieux and a standard lesion on the endothelial side

was inflicted by a method described in 1975 (Lopes Cardozo et al.). The

regeneration speed of the endothelium of the rinsed and the control eyes

were then measured; again no significant difference was found.

These findings made the severity of the lesions made locally in spite of the

use of the operation even more striking.

Fig. 1 shows a 6 mm corneal trephine specimen enlarged 40 x; the local

lesion made by the contact between the rinsing cannula and the endothe-

lium is obvious. Fig. 2 shows another 6 mm corneal trephine specimen enlarged 40 x. In

this photograph the endothelial damage can be seen caused by directing the

stream of fluid towards the endothelium instead of in the plane of the iris.

As the rabbit cornea is very limp the specimens folded double several times

when they were being freed; in Fig. 3 the curved defects where the two

layers of endothelium touched are visible.

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Fig. 1. Corneal trephine specimen, 6 mm diameter 40 x. Local lesion from contact between cannula and endothelium.

Fig. 2. Corneal trephine specimen, 6 mm 40 x. Endothelial damage caused by directing stream of fluid towards endothelium.

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Fig. 3. Corneal trephine specimen, 6 mm 40 x. Curved defects due to cornea folding double.

u

Fig. 4. Flieringa's ring with long sutures attached to cornea.

In order to avoid these difficulties in the next series of tests we sutured a

very small Flieringa ring lightly to the cornea with 6 or 8, 10 x 0 perlon

stitches. During the experiment the endothelial surface of the cornea could be kept

away from the iris tissue all the time by tightening the long ring sutures

(Fig. 4). After the experiment the cornea could be cut free between the ring

and the limbus, ghile Flieringa's ring was kept raised all the time so that no

disturbing endothelial damage could occur.

For the next 3 series of experiments we used unselected experimental

animals which we could obtain free from the Department of Immuno-

haematology after they had been used for immunisation tests.

Neither in the series with alpha-chymotrypsin 0.05% nor the series with

acetylcholine was evidence of abnormalities on the cellular level obtained.

The effect of local damage, in spite of the maintenance of the anterior

chamber by raising the Flieringa ring, was again striking.

In the last 5 experimental animals the cornea was freed directly after the

ring was stitched on and an implantation lens was placed on the endothelial

surface without exerting any extra pressure.

Fig. 5 shows the effect of this procedure with a Binkhorst iridocapsular

lens with platinum loops (weight 0.02 gram); the contour of the lens can be clearly seen.

Fig. 5. Left. Endothelial damage due to placing iridocapsular Binkhorst lens with pla- tinum loops (weight 0.02 gram) on endothelial surface of cornea. Fig. 6. Right. Endothelial damage due to placing iridocapsular Worst lens with Supra- mid loops (weight 0.015 gram) on endothelial surface of cornea.

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Fig. 6 shows the effect of an iridocapsular Worst lens with Supramid loops

(weight 0.015 gram); in addition to the contour of the lens the junctions of the loops are also clearly visible.

The severity of the local lesion caused by pushing an intra-ocular lens, in

this case an intracapsular Binkhorst lens with platinum loops, over the endothelial surface of the cornea is shown in Fig. 7.

The intra-ocular lens was stained four times after the test with nitroblue

tetrazolium. No endothelial cells could be demonstrated on the surface of

the lens.

RESULTS

Examination of the corneal trephine specimens and whole corneas stained

with nitroblue tetrazolium provided no information about morphological

changes in the corneal endothelium.

The corneas of the animals whose anterior chamber had been rinsed with

Ringer's solution at 20 ~ or 35 ~ showed no significant differences from those

of the control eyes. Differences could not be found either between the corneas of eyes where 2 cc Chymotrase 0.05% or 2 cc acetylcholine had been

introduced into the anterior chamber and the corneas of the control eyes.

Quantitative differences could not be demonstrated by means of cell-

counts per unit of surface area on the endothelial side of the cornea

between the rinsed and the control eye.

When the corneas of the rinsed and the control eye were cultivated and a

standard lesion was inflicted on the endothelial side, measurement of the

speed of regeneration showed no significant difference.

Fig. 7. Endothelial damage due to pushing an intra-ocular lens over the endothelial surface of the cornea.

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The ef fec t of the local lesion caused by the rinsing cannula or the stream

of fluid itself was very not iceable .

The lesions caused by placing an intra-ocular Binkhors t or Worst lens on

the endothel ia l surface of the cornea was also considerable.

The effect of pushing an intra-ocular lens over the endothel ia l surface of

the cornea was disastrous. Unfo r tuna te ly endothel ia l cells could no t be

demons t ra ted on the surface of the lens with n i t roblue te t razol ium staining.

CONCLUSION

Within the limits of this s tudy, no morphologica l changes in the endo-

the l ium of rabbi ts ' corneas could be demons t ra ted after rinsing with

Ringer 's solut ion at 20 ~ or 35 ~ , or after the in t roduc t ion of 2 cc

a lpha-chymotryps in 0.05% or 2 cc acetylchol ine.

The severity of the local lesions on the endothel ia l side of the cornea

which were caused by manipula t ions in the anter ior chamber were very

striking in spite of the use of the opera t ion microscope.

REFERENCES

Kaufman, H.E., Capetla, J.A., & Robbins, J.E. The human corneal endothelium. A m e r J. Ophthal. 61:835 - 841 (1966).

Lopes Cardozo, O., & Dandreux, M.R. Verslag van de 16e federatieve vergadering van medisch-biologische verenigingen en van verenigingen ter bevordering van her klinisch wetenschappelijk onderzoek. 2-4 april 1975. Utrecht 1975. pp. 282.

l~,filler, David & Claes H. Dohlman. Effect of cataract surgery on the cornea. Trans. Amer. Ac. OphthaL & Otolaryng. 74:369 - 374 (1970).

Stocker, F.M., Matton-van Leeuwen, M.Th., & Georgiade, N. Influence of alpha- chymotrypsine on the endothelial corneal dystrophy. Trans. Amer. Ophthal. Soc. 60: 2 0 2 - 212 (1962).

Author's address: University Medical Centre Dept. of Ophthalmology Leyden The Netherlands

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