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Cataracts and Open-Angle Glaucoma
CATARACTS A N D OPEN-ANGLE
GLAUCOMA
T H E EFFECT OF CATARACT EXTRACTION ON VISUAL FIELDS JOHN F . BIGGER, M . D . , AND BERNARD BECKER, M . D . St. Louis, Missouri
Serial testing of the visual fields in patients with glaucoma provides the basis for our therapeutic regimens. However, the interpretation of visual field changes in glaucoma is often complicated by a miotic pupil and particularly by axial lens opacities. ' The present study reports the alterations in visual fields in 90 eyes with primary openangle glaucoma subjected to uncomplicated cataract extraction. 1 2
METHODS
The records of 64 patients with primary open-angle glaucoma, who had undergone uncomplicated cataract extraction in one or both eyes, were reviewed. The criteria for inclusion in this study are reported elsewhere, but they are summarized here. The diagnosis of glaucoma was based on the presence of glaucomatous visual field loss in at least one eye of 50 of the 64 patients ( 7 8 % ) . The remaining patients demonstrated spontaneous intraocular pressures of 30 mm Hg or greater prior to institution of therapy. All eyes had gonioscopically open angles, and all were on medical therapy at the time of cataract extraction. Only eyes with uncomplicated intracapsular cataract extractions were included. In the 64 patients, there were 100 eyes which met the above criteria. Of these there were 90 eyes in which both preoperative and postoperative visual fields were available for 8
review. These are the subject of the present report. In 51 eyes, the visual fields were done with the Goldmann perimeter. The remainder were done using the tangent screen. The preoperative visual fields were reviewed and grouped according to the presence or absence of specific glaucomatous field defects. Visual fields which demonstrated partial or complete arcuate scotomas, with or without associated peripheral field changes, were considered glaucomatous. Generalized depression of all isopters, enlargement of the blind spot and baring of the blind spot were considered visual field changes nonspecific for glaucoma. Following cataract extraction, the visual fields during the first postoperative year were compared to the preoperative fields for evidence of change. Also noted was the visual acuity at the onset of the visual field defect, the duration of the visual field defect prior to cataract extraction, and the intraocular pressure. RESULTS
For the 90 sets of visual fields evaluated, Table 1 summarizes the prevalence of preoperative visual field defects. There were 41 eyes which, by our criteria, demonstrated a field defect characteristic of glaucoma. The other 49 eyes demonstrated either no field defect preoperatively or a defect which was felt to be nonspecific for glaucoma.
From the Department of Ophthalmology, Washington University School of Medicine, Saint Louis, Missouri. This study was supported by grant EY 00336 from the National Eye Institute, Bethesda, Maryland. Presented in part at the Spring National Meeting of the Association for Research in Ophthalmology, Sarasota, Florida, May 1-5, 1970. Reprint requests to Bernard Becker, M . D , Department of Ophthalmology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, Missouri 63110. 335
TABLE 1 PREVALENCE OF VISUAL FIELD DEFECTS PRIOR TO CATARACT EXTRACTION Type of Field Defects Nonspecific Glaucomatous Total
No. Eyes 49 41 90
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TABLE 2
No change Improved Worse
1971
TABLE 3
ALTERATIONS IN GLAUCOMATOUS FIELD DEFECTS IN 41 EYES FOLLOWING CATARACT EXTRACTION
Postoperative Status
JANUARY,
VISUAL ACUITY AT THE ONSET OF THE GLAUCOMATOUS FIELD DEFECT
No. Eyes 23 17 1
For those eyes without specific glaucomatous visual field defects preoperatively, the only change which occurred following cataract extraction was improvement in sensitivity, which could be expected from improved visual acuity. Consequently, this group is not considered further in this report. It is interesting to note that the loss of sensitivity with constriction of fields in these eyes did not mask the presence of true glaucomatous defects, as none of these were found postoperatively. Table 2 summarizes the visual field changes which occurred following cataract extraction in those eyes with preoperative glaucomatous field loss. Twenty-three eyes showed only improved sensitivity without alterations in the basic configuration of their field defects. These eyes were classified as unchanged. There were seventeen eyes which demonstrated disappearance of partial or complete arcuate scotomas. These visual fields were classified as improved. The preoperative and postoperative visual fields of six of these eyes are shown in Figures 1 through 6. Thus, 41% of the eyes with glaucomatous field loss demonstrated disappearance of part or all of their field defect. One eye with advanced field loss lost central fixation following cataract surgery. The eyes with recovery and those without recovery of visual field are compared, in Tables 3, 4 and 5, with respect to visual acuity and glaucoma control at the onset of the visual field defect and to the duration of the visual field defect prior to cataract extraction. There are no differences between the
Postoperative Field Visual Acuity
Improved (No. eyes)
No. Change (No. eyes)
20/20-20/40 20/50-20/70 20/80-20/100 20/200 20/400
3 5 3 3 3
4 8 5 3 3
17
23
Total
TABLE 4 GLAUCOMA CONTROL AT ONSET OF VISUAL FIELD DEFECT
Postoperative Field Glaucoma Control
Improved (No. eyes)
Good (IOP<20) Marginal (IOP 20-25) Poor (IOP > 25) Total
No Change (No. eyes)
4 6 7
3 8 12
17
23
TABLE 5 DURATION OF FIELD DEFECT PRIOR TO CATARACT EXTRACTION
Postoperative Field Duration
0-6 months 6-12 months 1-2 years Over 2 years Total
Improved (No. eyes)
No Change (No. eyes)
9 6 1 1
2 4 12 5
17
23
two groups with respect to either the visual acuity or glaucoma control at the onset of their visual field defects. However, as shown in Table 5, 15 of the 17 field defects ( 8 9 % )
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Fig. 1 (Bigger and Becker). Case No. 14. Top: Visual field showing baring of the blind spot and a superior arcuate scotoma, three months prior to cataract extraction ( V 4 and III4 white) ; vision 20/200, intraocular pressure 24 mm Hg. Bottom: Same eye six months following cataract extraction (IV4 and 114 white) ; vision 20/30, intraocular pressure 22 mm Hg.
Fig. 2 (Bigger and Becker). Case No. 22. Top: Visual field showing a superior arcuate scotoma, six months prior to cataract extraction (114 and 14 white) ; vision 20/100, intraocular pressure 24 mm Hg. Bottom : Same eye seven months following cataract extraction (114 and 12 white) ; vision 20/30, intraocular pressure 14 mm Hg.
which disappeared postoperatively had developed within one year of the time cataract extraction was done. In contrast, only six of the 23 field defects (26% ) which did not improve were of this duration.
TABLE 6
Comparison of the mean intraocular pressures during the preoperative and one year postoperative period for the same groups revealed no differences. This is presented in Table 6. Both groups demonstrate a period of lower intraocular pressure during the first weeks following cataract extraction, but the mean intraocular pressure for each group is the same at all times.
PRE- AND POSTOPERATIVE MEAN I O P IN EYES WITH GLAUCOMATOUS FIELD DEFECTS
Mean IOP Time (in months)
Postoperative Improved Fields
Postoperative Unchanged Fields
Preoperative
21.2
19.7
Postoperative 0-1 2-4 5-9 10-15
14.1 20.3 19.1 20.7
14.0 20.4 19.4 19.3
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«HO
Fig. 3 (Bigger and Becker). Case No. 25. T o p : Visual field showing a superior arcuate scotoma and nasal step, one month prior to cataract extraction (14 white) ; vision 20/60, intraocular pressure 24 mm Hg. Bottom: Same eye nine months following cataract extraction (114 and 13 white) ; vision 20/30, intraocular pressure 21 mm Hg.
DISCUSSION
The present series has demonstrated that 41% of glaucomatous visual field defects may disappear following cataract extraction. This occurred in spite of stringent criteria for classifying a defect as glaucomatous. T o explain this, there are two possible mechanisms which must be considered. It has been demonstrated that field defects in eyes with axial lens opacities and a miotic pupil may occur from the conditions of decreased retinal illumination. - These defects may, in all respects, simulate defects occur1
2
JANUARY, 1971
m
Fig. 4 (Bigger and Becker). Case No. 32. Top: Visual field showing a superior arcuate scotoma two months prior to cataract extraction (14 and 13 white) ; vision 20/200, intraocular pressure 20 mm Hg. Bottom: Same eye seven months following cataract extraction (114 and 13 white) ; vision 20/30, intraocular pressure 23 mm Hg.
ring secondary to elevated intraocular pressure. In addition to the generalized reduction in retinal illumination from generalized lens opacities, it is also possible that a focal opacity, especially posteriorly in the lens, may lead to a focal visual field defect. Field defects, when due to these causes, should be expected to disappear following cataract extraction as those conditions which create the decreased illumination are removed. On the other hand, it should also be possible to reproduce these defects postoperatively if the target size and illumination are sufficiently 4
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Fig. 5 (Bigger and Becker). Case No. 41. T o p : Visual field showing double arcuate scotoma, present for one year prior to cataract extraction (III4 white) ; vision 20/200, intraocular pressure 20 mm Hg. Bottom: Same eye six months following cataract extraction ( 14 white) ; vision 20/70, intraocular pressure 17 mm Hg.
Fig. 6 (Bigger and Becker). Case No. 65. Top: Visual field snowing superior arcuate defect and nasal step, eight months prior to cataract extraction (II14 and 114 white) ; vision 20/100, intraocular pressure 23 mm Hg. Bottom : Same eye four months following cataract extraction (III4 and 14 white) ; vision 20/50, intraocular pressure 17 mm Hg.
reduced. T o date, we have not been able to do this. Decreased retinal illumination by both the lens opacities and the pupillary miosis may well explain some of the reversible field defects of the present series. However, it should be noted that other eyes with similarly decreased retinal illumination and visual acuity continued to demonstrate their field defects following cataract extraction. An alternative mechanism for recovery of visual field in this series must also be considered. It has been demonstrated that glaucomatous visual field defects are reversible. -
According to Kölker and associates, this occurs with lowering of intraocular pressure and is most likely to occur when the field defect is of recent onset. In the present series it was shown that visual field recovery occurred in 15 of 21 eyes ( 7 1 % ) with defects present for less than one year, but in only two of 19 eyes ( 1 1 % ) with defects of longer duration (Table 5 ) . These findings strongly suggest that recovery of visual field may occur, in defects of short duration, when the intraocular pressure is lowered during the early postoperative period following cataract
5
8
5
340
AMERICAN JOURNAL OF OPHTHALMOLOGY
extraction. T o prove this mechanism, one should be able to find a visual field defect which persists following cataract extraction and subsequently disappears during the period of lower intraocular pressure. Unfortunately, visual field testing was not done in the very early postoperative period in any of the eyes in the present series. Analysis of the preoperative records of all eyes with glaucomatous field defects revealed that the visual acuity at the time of development of the field defect and the status of glaucoma control had no predictive value in determining which field defects recovered after cataract extraction. Nor was there any difference in the mean intraocular pressures following cataract extraction in those eyes with or without recovery of visual field. The only factor which appeared to have predictive value was the duration of the field defect, as those of shorter duration had a much greater incidence of recovery. Although it is likely that decreased retinal illumination secondary to lens opacities and miotic pupils contributed to the field defect as plotted, our data is more consistant with the possibility that reversal of the visual field defects of recent onset occurred during the period of lower intraocular pressure which follows cataract extraction. It is apparent that a number of our patients who were showing progressive field loss, at a time when the intraocular pressure of many was not well controlled, might likely be considered candidates for primary glaucoma surgery or for combined cataract extraction and glaucoma surgery. W e have elected to treat such patients by cataract extraction alone as the primary procedure. The efficacy of this management is shown by the improvement in glaucoma control and ease
JANUARY, 1971
of management of the glaucoma, and by the frequent reversal of visual field changes in this series. Ultimately, only two eyes in our series required glaucoma surgery, considerably fewer than one would have predicted from preoperative evaluation. 3
SUMMARY
The visual fields were examined in 90 eyes of 64 patients with primary open-angle glaucoma and cataract. Following uncomplicated cataract extraction, 17 ( 4 1 % ) of the 41 eyes with glaucomatous visual field loss preoperatively demonstrated disappearance of a partial or complete arcuate scotoma. Although it is likely that decreased retinal illumination secondary to lens opacities and miotic pupils contributed to the field defect as plotted, the possibility must be considered of reversal of the recent defects during a period of hypotony following cataract surgery. When indicated, cataract extraction is an effective primary procedure not only for restoration of vision but also for control of glaucoma and reversal of field loss. REFERENCES
1. Harrington, D. O.: The Visual Fields, 2nd ed. St. Louis, Mosby, 1964, chaps. 7, 8, and 11. 2. Forbes, M. : Influence of miotics on visual fields in glaucoma. Invest. Ophth. 5:139, 1966. 3. Bigger, J. F , and Becker, B.: Cataracts and open-angle glaucoma. The effect of uncomplicated cataract extraction on glaucoma control. T o be published. 4. Lyne, A. J, and Phillips, C. I. : Visual field defects due to opacities in the optical media. Brit. J. Ophth. 53:119, 1969. 5. Kölker, A. E., Becker, B , and Mills, D. W . : Intraocular pressure and visual fields : Effects of corticosteroids. Arch. Ophth. 72:772, 1964. 6. Armaly, M. F. : The visual field defect and ocular pressure level in open angle glaucoma. Invest Ophth. 8:105, 1969.
GLAUCOMA
T H E EFFECT OF CATARACT EXTRACTION ON VISUAL FIELDS JOHN F . BIGGER, M . D . , AND BERNARD BECKER, M . D . St. Louis, Missouri
Serial testing of the visual fields in patients with glaucoma provides the basis for our therapeutic regimens. However, the interpretation of visual field changes in glaucoma is often complicated by a miotic pupil and particularly by axial lens opacities. ' The present study reports the alterations in visual fields in 90 eyes with primary openangle glaucoma subjected to uncomplicated cataract extraction. 1 2
METHODS
The records of 64 patients with primary open-angle glaucoma, who had undergone uncomplicated cataract extraction in one or both eyes, were reviewed. The criteria for inclusion in this study are reported elsewhere, but they are summarized here. The diagnosis of glaucoma was based on the presence of glaucomatous visual field loss in at least one eye of 50 of the 64 patients ( 7 8 % ) . The remaining patients demonstrated spontaneous intraocular pressures of 30 mm Hg or greater prior to institution of therapy. All eyes had gonioscopically open angles, and all were on medical therapy at the time of cataract extraction. Only eyes with uncomplicated intracapsular cataract extractions were included. In the 64 patients, there were 100 eyes which met the above criteria. Of these there were 90 eyes in which both preoperative and postoperative visual fields were available for 8
review. These are the subject of the present report. In 51 eyes, the visual fields were done with the Goldmann perimeter. The remainder were done using the tangent screen. The preoperative visual fields were reviewed and grouped according to the presence or absence of specific glaucomatous field defects. Visual fields which demonstrated partial or complete arcuate scotomas, with or without associated peripheral field changes, were considered glaucomatous. Generalized depression of all isopters, enlargement of the blind spot and baring of the blind spot were considered visual field changes nonspecific for glaucoma. Following cataract extraction, the visual fields during the first postoperative year were compared to the preoperative fields for evidence of change. Also noted was the visual acuity at the onset of the visual field defect, the duration of the visual field defect prior to cataract extraction, and the intraocular pressure. RESULTS
For the 90 sets of visual fields evaluated, Table 1 summarizes the prevalence of preoperative visual field defects. There were 41 eyes which, by our criteria, demonstrated a field defect characteristic of glaucoma. The other 49 eyes demonstrated either no field defect preoperatively or a defect which was felt to be nonspecific for glaucoma.
From the Department of Ophthalmology, Washington University School of Medicine, Saint Louis, Missouri. This study was supported by grant EY 00336 from the National Eye Institute, Bethesda, Maryland. Presented in part at the Spring National Meeting of the Association for Research in Ophthalmology, Sarasota, Florida, May 1-5, 1970. Reprint requests to Bernard Becker, M . D , Department of Ophthalmology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, Missouri 63110. 335
TABLE 1 PREVALENCE OF VISUAL FIELD DEFECTS PRIOR TO CATARACT EXTRACTION Type of Field Defects Nonspecific Glaucomatous Total
No. Eyes 49 41 90
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TABLE 2
No change Improved Worse
1971
TABLE 3
ALTERATIONS IN GLAUCOMATOUS FIELD DEFECTS IN 41 EYES FOLLOWING CATARACT EXTRACTION
Postoperative Status
JANUARY,
VISUAL ACUITY AT THE ONSET OF THE GLAUCOMATOUS FIELD DEFECT
No. Eyes 23 17 1
For those eyes without specific glaucomatous visual field defects preoperatively, the only change which occurred following cataract extraction was improvement in sensitivity, which could be expected from improved visual acuity. Consequently, this group is not considered further in this report. It is interesting to note that the loss of sensitivity with constriction of fields in these eyes did not mask the presence of true glaucomatous defects, as none of these were found postoperatively. Table 2 summarizes the visual field changes which occurred following cataract extraction in those eyes with preoperative glaucomatous field loss. Twenty-three eyes showed only improved sensitivity without alterations in the basic configuration of their field defects. These eyes were classified as unchanged. There were seventeen eyes which demonstrated disappearance of partial or complete arcuate scotomas. These visual fields were classified as improved. The preoperative and postoperative visual fields of six of these eyes are shown in Figures 1 through 6. Thus, 41% of the eyes with glaucomatous field loss demonstrated disappearance of part or all of their field defect. One eye with advanced field loss lost central fixation following cataract surgery. The eyes with recovery and those without recovery of visual field are compared, in Tables 3, 4 and 5, with respect to visual acuity and glaucoma control at the onset of the visual field defect and to the duration of the visual field defect prior to cataract extraction. There are no differences between the
Postoperative Field Visual Acuity
Improved (No. eyes)
No. Change (No. eyes)
20/20-20/40 20/50-20/70 20/80-20/100 20/200 20/400
3 5 3 3 3
4 8 5 3 3
17
23
Total
TABLE 4 GLAUCOMA CONTROL AT ONSET OF VISUAL FIELD DEFECT
Postoperative Field Glaucoma Control
Improved (No. eyes)
Good (IOP<20) Marginal (IOP 20-25) Poor (IOP > 25) Total
No Change (No. eyes)
4 6 7
3 8 12
17
23
TABLE 5 DURATION OF FIELD DEFECT PRIOR TO CATARACT EXTRACTION
Postoperative Field Duration
0-6 months 6-12 months 1-2 years Over 2 years Total
Improved (No. eyes)
No Change (No. eyes)
9 6 1 1
2 4 12 5
17
23
two groups with respect to either the visual acuity or glaucoma control at the onset of their visual field defects. However, as shown in Table 5, 15 of the 17 field defects ( 8 9 % )
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337
Fig. 1 (Bigger and Becker). Case No. 14. Top: Visual field showing baring of the blind spot and a superior arcuate scotoma, three months prior to cataract extraction ( V 4 and III4 white) ; vision 20/200, intraocular pressure 24 mm Hg. Bottom: Same eye six months following cataract extraction (IV4 and 114 white) ; vision 20/30, intraocular pressure 22 mm Hg.
Fig. 2 (Bigger and Becker). Case No. 22. Top: Visual field showing a superior arcuate scotoma, six months prior to cataract extraction (114 and 14 white) ; vision 20/100, intraocular pressure 24 mm Hg. Bottom : Same eye seven months following cataract extraction (114 and 12 white) ; vision 20/30, intraocular pressure 14 mm Hg.
which disappeared postoperatively had developed within one year of the time cataract extraction was done. In contrast, only six of the 23 field defects (26% ) which did not improve were of this duration.
TABLE 6
Comparison of the mean intraocular pressures during the preoperative and one year postoperative period for the same groups revealed no differences. This is presented in Table 6. Both groups demonstrate a period of lower intraocular pressure during the first weeks following cataract extraction, but the mean intraocular pressure for each group is the same at all times.
PRE- AND POSTOPERATIVE MEAN I O P IN EYES WITH GLAUCOMATOUS FIELD DEFECTS
Mean IOP Time (in months)
Postoperative Improved Fields
Postoperative Unchanged Fields
Preoperative
21.2
19.7
Postoperative 0-1 2-4 5-9 10-15
14.1 20.3 19.1 20.7
14.0 20.4 19.4 19.3
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«HO
Fig. 3 (Bigger and Becker). Case No. 25. T o p : Visual field showing a superior arcuate scotoma and nasal step, one month prior to cataract extraction (14 white) ; vision 20/60, intraocular pressure 24 mm Hg. Bottom: Same eye nine months following cataract extraction (114 and 13 white) ; vision 20/30, intraocular pressure 21 mm Hg.
DISCUSSION
The present series has demonstrated that 41% of glaucomatous visual field defects may disappear following cataract extraction. This occurred in spite of stringent criteria for classifying a defect as glaucomatous. T o explain this, there are two possible mechanisms which must be considered. It has been demonstrated that field defects in eyes with axial lens opacities and a miotic pupil may occur from the conditions of decreased retinal illumination. - These defects may, in all respects, simulate defects occur1
2
JANUARY, 1971
m
Fig. 4 (Bigger and Becker). Case No. 32. Top: Visual field showing a superior arcuate scotoma two months prior to cataract extraction (14 and 13 white) ; vision 20/200, intraocular pressure 20 mm Hg. Bottom: Same eye seven months following cataract extraction (114 and 13 white) ; vision 20/30, intraocular pressure 23 mm Hg.
ring secondary to elevated intraocular pressure. In addition to the generalized reduction in retinal illumination from generalized lens opacities, it is also possible that a focal opacity, especially posteriorly in the lens, may lead to a focal visual field defect. Field defects, when due to these causes, should be expected to disappear following cataract extraction as those conditions which create the decreased illumination are removed. On the other hand, it should also be possible to reproduce these defects postoperatively if the target size and illumination are sufficiently 4
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CATARACTS A N D OPEN-ANGLE GLAUCOMA
Fig. 5 (Bigger and Becker). Case No. 41. T o p : Visual field showing double arcuate scotoma, present for one year prior to cataract extraction (III4 white) ; vision 20/200, intraocular pressure 20 mm Hg. Bottom: Same eye six months following cataract extraction ( 14 white) ; vision 20/70, intraocular pressure 17 mm Hg.
Fig. 6 (Bigger and Becker). Case No. 65. Top: Visual field snowing superior arcuate defect and nasal step, eight months prior to cataract extraction (II14 and 114 white) ; vision 20/100, intraocular pressure 23 mm Hg. Bottom : Same eye four months following cataract extraction (III4 and 14 white) ; vision 20/50, intraocular pressure 17 mm Hg.
reduced. T o date, we have not been able to do this. Decreased retinal illumination by both the lens opacities and the pupillary miosis may well explain some of the reversible field defects of the present series. However, it should be noted that other eyes with similarly decreased retinal illumination and visual acuity continued to demonstrate their field defects following cataract extraction. An alternative mechanism for recovery of visual field in this series must also be considered. It has been demonstrated that glaucomatous visual field defects are reversible. -
According to Kölker and associates, this occurs with lowering of intraocular pressure and is most likely to occur when the field defect is of recent onset. In the present series it was shown that visual field recovery occurred in 15 of 21 eyes ( 7 1 % ) with defects present for less than one year, but in only two of 19 eyes ( 1 1 % ) with defects of longer duration (Table 5 ) . These findings strongly suggest that recovery of visual field may occur, in defects of short duration, when the intraocular pressure is lowered during the early postoperative period following cataract
5
8
5
340
AMERICAN JOURNAL OF OPHTHALMOLOGY
extraction. T o prove this mechanism, one should be able to find a visual field defect which persists following cataract extraction and subsequently disappears during the period of lower intraocular pressure. Unfortunately, visual field testing was not done in the very early postoperative period in any of the eyes in the present series. Analysis of the preoperative records of all eyes with glaucomatous field defects revealed that the visual acuity at the time of development of the field defect and the status of glaucoma control had no predictive value in determining which field defects recovered after cataract extraction. Nor was there any difference in the mean intraocular pressures following cataract extraction in those eyes with or without recovery of visual field. The only factor which appeared to have predictive value was the duration of the field defect, as those of shorter duration had a much greater incidence of recovery. Although it is likely that decreased retinal illumination secondary to lens opacities and miotic pupils contributed to the field defect as plotted, our data is more consistant with the possibility that reversal of the visual field defects of recent onset occurred during the period of lower intraocular pressure which follows cataract extraction. It is apparent that a number of our patients who were showing progressive field loss, at a time when the intraocular pressure of many was not well controlled, might likely be considered candidates for primary glaucoma surgery or for combined cataract extraction and glaucoma surgery. W e have elected to treat such patients by cataract extraction alone as the primary procedure. The efficacy of this management is shown by the improvement in glaucoma control and ease
JANUARY, 1971
of management of the glaucoma, and by the frequent reversal of visual field changes in this series. Ultimately, only two eyes in our series required glaucoma surgery, considerably fewer than one would have predicted from preoperative evaluation. 3
SUMMARY
The visual fields were examined in 90 eyes of 64 patients with primary open-angle glaucoma and cataract. Following uncomplicated cataract extraction, 17 ( 4 1 % ) of the 41 eyes with glaucomatous visual field loss preoperatively demonstrated disappearance of a partial or complete arcuate scotoma. Although it is likely that decreased retinal illumination secondary to lens opacities and miotic pupils contributed to the field defect as plotted, the possibility must be considered of reversal of the recent defects during a period of hypotony following cataract surgery. When indicated, cataract extraction is an effective primary procedure not only for restoration of vision but also for control of glaucoma and reversal of field loss. REFERENCES
1. Harrington, D. O.: The Visual Fields, 2nd ed. St. Louis, Mosby, 1964, chaps. 7, 8, and 11. 2. Forbes, M. : Influence of miotics on visual fields in glaucoma. Invest. Ophth. 5:139, 1966. 3. Bigger, J. F , and Becker, B.: Cataracts and open-angle glaucoma. The effect of uncomplicated cataract extraction on glaucoma control. T o be published. 4. Lyne, A. J, and Phillips, C. I. : Visual field defects due to opacities in the optical media. Brit. J. Ophth. 53:119, 1969. 5. Kölker, A. E., Becker, B , and Mills, D. W . : Intraocular pressure and visual fields : Effects of corticosteroids. Arch. Ophth. 72:772, 1964. 6. Armaly, M. F. : The visual field defect and ocular pressure level in open angle glaucoma. Invest Ophth. 8:105, 1969.