AMERICAN JOURNAL OF OPHTHALMOLOGY VOLUME 62 NOVEMBER, 1966 NUMBER 5

CHOROIDAL DETACHMENT AND RETINAL SURGERY

A CLINICAL AND EXPERIMENTAL STUDY

W. R. HAWKINS, M.D., AND C. L. SCHEPENS, M.D. Boston, Massachusetts

Choroidal detachment, in association with retinal surgery, results from either hem­orrhagic1,2 or serous2'8 accumulation of fluid. The hemorrhagic process occurs dur­ing the operative procedure and presents as a rapidly forming elevation of the choroid. The serous effusion causes a more slowly developing detachment of the choroid that becomes clinically manifest during the post­operative period. Hemorrhagic and serous detachments of the choroid also occur in as­sociation with anterior segment surgery al­though the etiologic factors are somewhat different.4

The present study was undertaken to in­vestigate the incidence, pathogenesis, and significance of choroidal detachment occur­ring in association with retinal detachment surgery. The report is divided into two sec­tions, clinical and experimental.

CLINICAL STUDY

MATERIAL AND METHODS

Data were extracted from records of the Retina Associates and the Retina Service of the Massachusetts Eye and Ear Infirmary. Alphabetically consecutive records were re­viewed of 1,500 patients who had undergone surgery for retinal detachment between

From the Department of Retina Research, In­stitute of Biological and Medical Sciences, Retina Foundation, and the Department of Ophthalmol­ogy, Massachusetts Eye and Ear Infirmary. This work was supported by a Public Health Service research grant B3489 of the National Institute of Neurological Diseases and Blindness, U. S. Pub­lic Health Service.

1961 and 1964. Only primary procedures were included. Details relating to the inci­dence of both hemorrhagic and serous de­tachment of the choroid were studied statis­tically. The findings were considered significant when the probability that they had occurred by chance was less than 5% ( P < 0 . 0 5 ) . Clinical features of choroidal detachment were abstracted from postopera­tive fundus sketches. These sketches were made by the surgeon following examination with an indirect stereoscopic ophthal­moscope. Complications resulting from de­tachment of the choroid, and their manage­ment, were also reviewed.

FINDINGS

Hemorrhagic detachment of the choroid. Among the 1,500 cases reviewed, subchoroi-dal hemorrhage occurred during the opera­tive procedure in 15, an incidence of 1%. In all cases the hemorrhage followed the cho­roidal perforation and the acute hypotony associated with the release of subretinal fluid. The dark, convex elevation of the choroid was located in the same quadrant as the perforation site in 11 of the 15 cases (73%). However, external bleeding from the perforation site immediately following choroidal puncture was noted in three cases only (20%).

As the subchoroidal hemorrhage in­creased in size there was an accompanying increase in intraocular pressure. In eight cases (53%) the pressure became markedly elevated. Drainage through a sclerotomy

813

814 AMERICAN JOURNAL OF OPHTHALMOLOGY NOVEMBER, 1966

was necessary in these cases to control glau­coma. Drainage also was performed in two additional cases (14%) in which the hemor­rhage was quite large. In the five other cases (33%) the hemorrhage was small and surgi­cal drainage was not necessary.

The patients with subchoroidal hemor­rhage often had high myopia. Eight of the 15 cases (53%) had refractive errors of — 8.0D or more. This differed significantly from the 7% incidence of comparable myopia in all 1,500 cases. In each of these patients with high myopia, degenerative changes of the peripheral choroid and retina had been noted during the preoperative ex­amination.

Another common feature of the cases with hemorrhagic choroidal detachment was the posterior position of the scleral buckle. The average distance from the limbus to the posterior edge of the retinal breaks was 18 mm. In 13 of the 15 cases (87%) the retinal breaks were located posterior to the equator of the globe. The presence of vortex veins complicated the undermining of the sclera in seven cases (47%).

In the postoperative period, a progressive extension of the choroidal detachment com­monly occurred before absorption began. Four cases (27%) required drainage of the subchoroidal fluid in a subsequent proce­dure, and at this time serosanguinous fluid was released. In all cases absorption was complete within four to six weeks.

Serous choroidal detachment. During the postoperative period, 348 cases of serous choroidal detachment were noted, an inci­dence of 23% for the 1,485 operations re­maining after exclusion of the 15 cases with hemorrhagic choroidal detachment.

Clinical features. Typically, serous de­tachment of the choroid was noted on the first or second postoperative day (table 1), and appeared as a prominent, brown-col­ored, smooth and immobile elevation. In many cases, however, the choroid was mini­mally elevated and its extent difficult to ap­preciate by ophthalmoscopic examination. Serous detachment of the choroid occurred

TABLE 1 DETECTABLE ONSET OF SEROUS TYPE

Postoperative Day No. Patients Percentage

First Second Third Fourth Fifth Sixth More than

TOTAL

six days

98 96 46 41 22 22 23

348

28 28 13 12 6 6 7

100%

most frequently at the level of the equator with extension anteriorly. Following scleral buckling procedures it was generally found in a meridian that was either adjacent to or opposite the area of the buckle. Less fre­quently serous choroidal detachment was noted in the area of the buckle. In these cases the choroidal detachment usually was noted on either the anterior or posterior as­pect of the buckle. It was exceptional for a prominent elevation of the choroid to occur over the convexity of the buckle.

In approximately 10% of the 348 cases reviewed, the serous choroidal detachment became extensive and involved all quad­rants. In such instances (fig. 1) the entire ora serrata was visible without scleral in­dentation. The rounded choroidal elevations had a scalloped contour since the vortex am-pullas maintained an attachment to the sclera. Occasionally the detachment was deeply creased along the horizontal meridian when the choroid remained adherent to the sclera along the course of the long ciliary artery and nerve.

The serous detachment of the choroid often increased in size for two to four days after onset. Then absorption began and was usually complete by the end of the second postoperative week, except in extensive cases. Following a slow absorption, a mild, but diffuse, pigmentary proliferation occa­sionally developed in the area of previous choroidal detachment. Sometimes faint pig­ment lines formed, resembling demarcation lines.

Incidence. The incidence of serous cho­roidal detachment increased with the pa-

VOL. 62, NO. S C H O R O I D A L D E T A C H M E N T A N D R E T I N A L SURGERY 815

tient's age (table 2) . The incidence was 3% up to the age of 20 years. It was 20% for patients between 21 and 60 years of age. For patients 61 and over, the incidence was 33%. The differences between these three percentages are significant.

Data relating to the operative procedure showed that subretinal fluid was released through a choroidal perforation in 1,314 cases, of which 26% subsequently developed a choroidal detachment. In cases which did not require perforation, the incidence was 7%, which was significantly lower (table 3) . It should be noted that the hypotony associ­ated with release of subretinal fluid was transient. In the scleral buckling procedures the intraocular pressure was restored when the scleral sutures were pulled up. Further­more, at the termination of the procedure, the intraocular pressure was adjusted to ap­proximately IS mm Hg.

Vortex veins interfered with the under­mining of the scleral flaps in 77 of the 1,485 cases (5%) . These were generally the most difficult cases with breaks located posterior to the equator. Several varieties of insult to the vortex veins were noted in the operative reports: (1) the intrascleral course of a vein was cut during the scleral undermining on 14 occasions; (2) 30 veins were obliterated by diathermy; (3) on 46 occasions the in­trascleral course and scleral exit of a vein were encountered during the dissection of the scleral bed; and (4) thrombosis of a vortex vein was noted in two instances dur­ing the operation, apparently as a result of surgical manipulations. Among the 77 eyes in which the vortex veins were subjected to

TABLE 2 INFLUENCE OF AGE ON INCIDENCE OF SEROUS TYPE

Age Group

(yr)

0-20 21-40 41-60

61 and over

TOTALS

Cases of Cases of Retinal Choroidal

Detachment Detachment

131 157 625 572

1,485

4 29

126 189

348

Percentage

3 18 20 33

23

TABLE 3 INFLUENCE OF CHOROIDAL PERFORATION ON

INCIDENCE OF SEROUS TYPE

Cases of Cases of Retinal Choroidal

Detachment Detachment

Perforation 1,314 336 No Perforation 171 12

TOTALS 1,485 348

Percentage

26 7

23

TABLE 4 INFLUENCE OF VORTEX VEIN TRAUMA ON

INCIDENCE OF SEROUS TYPE

Vein Cases of r l . . , Involve- Retinal D e t a c h m e n t Percentage

ment Detachment U e t a c n m e n t

None One Two

1,408 62 15

314 23 11

22 37 73

TOTALS 1,485 348 23

one or more of the insults described, a sin­gle vein was involved in 62 cases (4%) and two or more in 15 (1%) . Choroidal detach­ment occurred after the operation in 37% of the eyes in which one vein was damaged, and in 73% of those in which two veins were involved (table 4) . The incidence of choroidal detachment associated with trau­ma to either one or two vortex veins was significantly higher than the incidence of 22% in operations which did not affect vor­tex veins.

Other factors such as sex of the patient, refractive error, aphakia and extent of the area treated with diathermy did not signifi­cantly affect the incidence of serous choroidal detachment.

Complications. In almost all cases the choroidal detachment absorbed without com­plicating the postoperative course. The most frequent complication noted was secondary glaucoma which developed in four of 15 eyes (27%) with hemorrhagic detachment and in 19 of the 348 eyes (5%) with serous detachment. Corneal edema, noted on the first or second postoperative day, usually

816 AMERICAN JOURNAL OF OPHTHALMOLOGY NOVEMBER, 1966

suggested an increase of intraocular pres­sure. In nine of the 23 eyes (39%) with postoperative glaucoma, the anterior cham­ber became shallow, especially in the periph­ery. Four eyes were aphakic. In eight of the 23 eyes (35%) vortex veins had compli­cated the dissection of the scleral bed. In spite of the fact that corneal edema made visualization of the fundus unsatisfactory, the choroidal detachment was noted to in­volve all quadrants in 10 of the 23 eyes (43%).

The glaucoma was controlled in 17 of the 23 cases (74%) by treatment consisting of acetazolamide, 250 mg four times daily, and 1% levo-epinephrine drops, twice daily. Occasionally, 4% pilocarpine drops were used. Medical therapy was ineffective in six cases. Surgical drainage of the sub-choroidal fluid with saline injection into the anterior chamber was performed in five of these cases. In the remaining case, because of wound infection in addition to the cho­roidal detachment, the silicone implants and sutures were removed. These surgical proce­dures resulted in successful control of the glaucoma in all six cases. Following absorp­tion of the subchoroidal fluid, it was possi­ble to discontinue the antiglaucomatous medication in all cases.

One other postoperative complication, ex­tensive choroidal detachment, which threat­ened to involve the macula, developed in two of the 15 eyes (13%) with hemorrhagic de­tachment and in five of the 348 eyes (1%) with serous detachment. These cases were treated with drainage of the subchoroidal fluid through a sclerotomy. In aphakic eyes, ocular volume was restored by injecting sa­line into the anterior chamber. But in phakic eyes saline was injected into the vitreous body in order to restore satisfactorily the ocular volume.

EXPERIMENTAL STUDY

The experimental procedures were de­signed to yield information relating to the pathogenesis of choroidal detachment fol­

lowing retinal surgery. The effects of scleral diathermy and hypotony were studied indi­vidually in animal eyes. Then, the effects of the combination of scleral diathermy with hypotony were investigated. And, finally, the effects of diathermy, hypotony, and vor­tex vein occlusion were observed.

MATERIAL AND METHODS

The operative procedures were performed on the eyes of eight squirrel monkeys, weighing 480 to 640 gm. Lateral canthotomy, removal of the lateral wall of the orbit, and tenotomy of the inferior rectus muscle were performed in each case to obtain satisfacto­ry exposure of the globe. On the fourth postoperative day the monkeys were an­esthetized and the eyes were examined and then enucleated. Formalin was used for fixation. The globes were opened and exam­ined with a dissecting microscope. The spec­imens were then embedded in paraffin and sections were stained with hematoxylin and eosin.

The 16 eyes used for experimentation were divided into four groups:

1. In two eyes, diathermy was applied in a 150-degree circumferential arc between the equator and the ora serrata. The intensi­ty was similar to that used clinically in reti­nal detachment surgery.

2. In two other eyes, hypotony was cre­ated by needle aspiration of approximately 0.2 ml of liquid vitreous through a scleroto­my located over the pars plana ciliaris.

3. In five eyes, scleral diathermy was ap­plied as just described and, following this, hypotony was created by aspiration of vitre­ous.

4. In seven eyes, the two inferior vortex veins were diathermized in addition to scler­al diathermy and vitreous aspiration.

FINDINGS

By ophthalmoscopic examination choroi­dal detachment was not recognized in any of the 16 eyes. Gross examination after open­ing the eyes showed the presence of an ante-

VOL. 62, NO. S CHOROIDAL DETACHMENT AND RETINAL SURGERY 817

riorly located choroidal detachment in two of the seven eyes subjected to diathermy, aspiration of fluid vitreous, and vortex vein occlusion.

Histologic preparations of the two eyes subjected to scleral diathermy only showed a vascular congestion and choroidal edema that was primarily localized to the diather-mized area. No choroidal edema was noted in the two eyes in which vitreous aspiration alone had been performed.

A suprachoroidal edema was noted in the five eyes subjected to diathermy and vitre­ous aspiration. The eosinophilic-staining edema fluid was present anterior to the equator. It separated the outer lamellar ele­ments of the choroid and ciliary body. In three eyes the edema extended all around the globe.

In the seven eyes subjected to diathermy, vitreous aspiration, and occlusion of two vortex veins, there was a prominent edema of the suprachoroidea. There was also congestion of choroidal vessels with some extravasation of red blood cells, especially in the quadrants drained by the occluded vortex veins. In two eyes the lamellar ele­ments of the suprachoroidea had been exten­sively separated by edema fluid. An ante­riorly located and prominent detachment of the choroid and ciliary body resulted (figs. 2 and 3) .

DISCUSSION

Our study of clinical records indicates that the following are significant factors in the occurrence of choroidal detachment

Fig. 3 (Hawkins and Schepens). Squirrel mon­key eye. Prominent detachment of choroid which extended almost to the optic disc. (X9.)

after operation for retinal detachment: acute hypotony following drainage of subre-tinal fluid, age of patient, and involvement of vortex veins during operation.

Hypotony is considered to be an impor­tant factor in the pathogenesis of serous choroidal detachment following anterior segment surgery.*"7 The acute decrease in pressure which occurs when the eye is opened is thought to cause an increased per­meability of the choroidal capillaries.5 As a result, edema fluid accumulates in the supra­choroidea during the postoperative period. The persistent hypotony that occurs from a leaking corneoscleral wound also has been emphasized as a cause of choroidal detachment.7 Persistent low intraocular pressure causes an increased pressure differential across the wall of the choroidal capillaries and promotes the transudation of fluid.6

In retinal detachment surgery, hypotony

Fig 2 (Hawkins and Schepens). Squirrel monkey eye. The choroid and ciliary body are elevated by serous fluid in which there is also extravasation of red blood cells. The choroidal detachment extended from the equator to the scleral spur and encircled the globe. (X9.)

818 AMERICAN JOURNAL OF OPHTHALMOLOGY NOVEMBER, 1966

occurs with the release of subretinal fluid. In scleral buckling procedures, this hypot-ony usually is relieved when the scleral mat­tress sutures are pulled up. If, however, the indentation of the implant fails to compen­sate for the evacuation of a large volume of subretinal fluid, balanced salt solution is in­jected to restore intraocular pressure to a normal level. Despite the pressure adjust­ment, subchoroidal fluid may begin to ac­cumulate, and the resulting choroidal de­tachment is noted typically on the first or second postoperative day.

In our clinical survey, the frequency of serous choroidal detachment following reti­nal surgery was found to be related to the patient's age. Recently, it has been demon­strated that aging is associated with degen­erative changes in the choriocapillaris as manifested by increased periodic-acid-Schiff staining and decreased cellularity of the ves­sel walls.8 These pathologic changes may predispose to increased permeability of the vessel walls and cause a significantly higher frequency of serous choroidal detachment in older patients.

Finally, vortex vein trauma was associ­ated with serous choroidal detachment. In that situation a transient increase in hydro­static pressure probably occurs within the choroidal capillaries. As a result there is a transudation before a new equilibrium is es­tablished.

The analysis of postoperative records re­vealed that the incidence of serous choroidal detachment was 23%. The real incidence was probably higher since a minor degree of choroidal detachment could easily escape no­tice clinically.

The location of serous choroidal detach­ment following scleral buckling procedures is an interesting feature that has been em­phasized previously.2 As a rule, serous cho­roidal detachment in humans does not ex­tend over the convexity of the scleral buckle. This may be due to stretching of the sclera and choroid over the silicone implant which would preclude accumulation of subchoroi­dal fluid in that area.

Hemorrhagic choroidal detachment oc­curred in 1% of the cases reviewed. The tendency for the highly myopic eye to de­velop this complication is possibly related to the degenerative changes which are known to occur in the choroidal vessels of such eyes.9 Hemorrhage may also occur in highly myopic eyes without trauma and one exam­ple is subretinal hemorrhage at the macula or Fuchs' spot. Initially, the subchoroidal hemorrhage was frequently located near the perforation site. In these cases, a choroidal vessel had been punctured, presumably by the perforating electrode. Postoperatively, a progressive extension of the choroidal de­tachment occurred before slow absorption began. This increase was due to a serous ac­cumulation of fluid following the hemorrha­gic insult, since serous as well as sanguinous fluid was obtained when a choroidal tap was performed.

Glaucoma was the most important compli­cation of choroidal detachment. The rise in pressure is probably related to a forward extension of the choroidal detachment. When the detachment reaches the scleral spur, it may cause a shallowing of the ante­rior chamber by forcing the ciliary body to rotate forward. This in turn compromises the filtration angle.

In the squirrel monkey scleral diathermy and release of fluid vitreous caused supra-choroidal edema with minimal elevation of the choroid. When two vortex veins were occluded, in addition, the suprachoroidal edema was more intense and a detachment of the choroid occurred in two of seven eyes. It has been noted that choroidal de­tachment is difficult to produce in ex­perimental animals.3 Hypotony,5'6 scleral trauma and hypotony,6 diathermy and hypotony10 and the introduction of fluid or instruments into the suprachoroidal space11

have been employed in previous experi­ments. Usually, an edema of the choroid was produced without significant choroidal de­tachment.

The exact relationship between the cho­roidal edema observed in experimental ani-

VOL. 62, NO. 5 CHOROIDAL DETACHMENT AND RETINAL SURGERY 819

mals and the choroidal detachment that oc­curs in humans is difficult to determine. In this regard, a factor not previously consid­ered is the age disparity. Since most labo­ratory animals are young, it may be that only a minimal accumulation of supracho­roidal edema fluid is to be expected.

A final consideration is the role of scleral diathermy in the pathogenesis of choroidal detachment accompanying retinal surgery. In our clinical survey the circumferential extent of the diathermized area did not affect the incidence of choroidal detachment. However, 12 cases of choroidal detachment occurred when no perforation was done to release the subretinal fluid. Thus, the di­athermy reaction obviously participated in the mechanism of the edema formation. Furthermore, in the animal experiments it was noted that edema and detachment of the choroid occurred only when diathermy was also used in the procedure. It would seem, therefore, that the choroidal injury pro­duced by diathermy is another factor that influences the incidence of choroidal detach­ment in association with retinal surgery.

SUMMARY

Choroidal detachment is a common sequel of retinal surgery. It may occur as either a hemorrhagic or a serous accumulation of fluid. In a series of 1,500 cases, hemorrhagic and serous choroidal detachments were ob­served in 1% and 23% of cases, respective-

Hemorrhagic choroidal detachment oc­curred following perforation and the acute hypotony associated with drainage of subretinal fluid. It was most common in highly myopic eyes. The development of se­rous choroidal detachment was associated with drainage of subretinal fluid, age of pa­tient, vortex vein involvement, and scleral diathermy. The clinical features of serous detachments were described.

Glaucoma was the most serious complica­tion of choroidal detachment; it disappeared following absorption of the choroidal de­tachment.

In the squirrel monkey choroidal detach­ment was produced following the combina­tion of scleral diathermy, vitreous aspira­tion, and destruction of two vortex veins. Scleral diathermy with vitreous aspiration produced suprachoroidal edema of a lesser degree.

20 Stamford Street (02114)

ACKNOWLEDGMENT

We wish to acknowledge the assistance of Tay­lor Smith, M.D., and Richard Donovan, V.M.D., in the pathologic studies. The fundus painting is by William J. Stenstrom.

REFERENCES

1. Tolentino, F. I., and Brockhurst, R. J.: Uni­lateral scleral icterus due to choroidal hemor­rhage. Arch. Ophth. 70:3S8, 1963.

2. Schepens, C. L.: Importance of choroidal detachment in fundus diagnosis. (Society Pro­ceedings.) Am. J. Ophth. 51:333, 1961.

3. Bernard, P.: Le decollement de la choroide: Bull. Soc. Ophtal. France. Suppl. 1963, p. 77.

4. Spaeth, E. B., and DeLong, P.: Detachment of the choroid: A clinical and histopathologic analysis. Arch. Ophth. 32 :217, 1944.

5. O'Brien, C. S.: Detachment of the choroid after cataract extraction: Clinical and experimen­tal studies, with report of 75 cases. Arch. Ophth. 14 :S27, 1935.

6. Capper, S. A., and Leopold, I. H.: Mecha­nism of serous choroidal detachment. Arch. Ophth. 55:101, 1956.

7. Verhoeff, F. H., and Waite, J. H.: Separation of the choroid, with report of a spontaneous case. Arch. Ophth. 55:38, 1925.

8. Friedman, E., Smith, T. A., and Kuwabara, T.: Senile choroidal vascular patterns and drusen. Arch. Ophth. 69 :220, 1963.

9. Hogan, M. J., and Zimmerman, L. E.: Ophthalmic Pathology: An Atlas and Textbook. Philadelphia, Saunders, 1962, p. 114.

10. Swan, K. C, Christensen, L., and Weisel, J. T.: Choroidal detachment in the surgical treat­ment of retinal separation. Arch. Ophth. 55:240, 1956.

11. Pau, V. H.: Ueber die Amotio Chorioidae (Spongiosis Chorioidae), Klin. Mbl. Augenh. 130:347, 1957.