ACTA O P H T H A L M O L O G I C A VOL. 55 1977
From the University Eye Clinic (Head: Salme Vannas), University of Helsinki, Helsinki, Finland
ENDOTHELIAL CELLS IN CAPSULAR GLAUCOMA BY ANTTI VANNAS, KlRSl SETXLA and PEKKA RUUSUVAARA
The clinical specular microscope has made it possible to study corneal endothelial cells in vivo. In this study we report f o r the first time cell densities of unilateral glaucoma patients compared to the normotensive control eyes of the same patient. The corneal endothelium of 27 unilateral capsular glaucoma patients was photographed with a clinical specular microscope. The endothelial cell density was lower in the affected eye than in the normotensive fellow eye in 15 cases. In 10 patients the cell density was the same in both eyes. In two cases the glaucoma eye had a higher density than the fellow eye. Comparison of the above groups showed a statistical difference in the number of glaucoma eyes with a lower cell density (15 lower against 2 higher). The endothelial cell density could not be correlated with the duration of treatment or severity of the glaucoma.
Key words: glaucoma, capsular - pseudo-exfoliation - exfoliation - fibrillopathia epitheliocapsularis - endothelial cell density - endothelial cell loss - clinical specular microscope.
Slit-lamp magnification is not sufficient for the study of endothelial cells. Only with the specular microscope can the size, morphology and quantity of endothelial cells be examined in vivo (Maurice 1968; Laing et al. 1975; Bourne & Kaufman 1976). The endothelial cell count of a young subject has been established to be around 500 000 (3300/mm*) by means of the specular microscope. The number of endothelial cells decreases with age, and the endothelial cell Received May 5 , 1977.
95 1 61*
Antti Vannas, Kirsi Setalii, Pekka Ruusuvaara Number of
patients
,
55-59 60-64 65-69 70-74 75-79 80-84
A g e group ( m i
Fig. I. Age and sex distribution of patients.
density of a subject aged 60 years is approximately 2600/mm2 (Bourne & Kaufman 1976). The endothelial cell count may also decrease after trauma when the cell regeneration capacity is either lacking or very limited (Kaufman et al. 1966; Stocker 1971; Bourne & Kaufman 1976). The purpose of this work was to study the effects of increased intraocular pressure on the endothelial cells of glaucoma patients, since earlier information on the subject is very meagre. In Irvine’s (1956) study of enucleated glaucomatous eyes, thinning of endothelial cells was demonstrated in light microscopy sections and in places the endothelium was missing.
Material and Methods The material consisted of 27 patients with uniocular capsular glaucoma which was diagnosed according to Becker & Shaffer (1976). All of them had unilateral glaucoma and a distinctly elevated intraocular pressure prior to glaucoma therapy. Twenty-five patients were undergoing pilocarpine treatment or other glaucoma therapy already at the time of photography. Treatment was instituted after endothelial photography in two recently diagnosed cases. Patients on whom an intrabulbar operation had been performed were excluded from the material because of potential surgical trauma to the endothelium. The normotensive eyes of each patient constituted the control series. The intraocular pressures were measured by Goldmann’s applanation tono952
Endothelial Cells in Capsular Glaucoma
meter, the visual fields were studied by Goldmann perimeter and the central visual field by Friedmann’s analyser. Tonography was performed as described by Garner (1965) by a trained person. The patients’ ages and sex distribution are presented in Fig. 1. The age range was 59-82 years. Women were in the majority. Fig. 2 shows the duration of glaucoma treatment and presence of possible visual field defects. The endothelial cells were photographed with a specular microscope (Seyber Inc). Several pictures, five 011 average, were taken of the central cornea of both eyes of each patient. The morphology and size of the endothelial cells were analysed by projecting the negative onto a screen. The density of the endothelial cells was determined by counting the number visible in the specular area. The magnification of the specular microscope was calculated by photographing from a standardised glass plate the calibration lines with an objective working distance which corresponds to the normal thickness of the cornea. The final magnification in analysing the cells from the screen was x 730. The cells were counted from three photographs and their mean was entered as the result. An area corresponding to 0.012 mm2 on the endothelium was calculated in each photograph and the result was expressed as the number of cells per mm2.
@ = field defect
c]
= no
field defect
n
1-2
2-3
3-4
4-5
5-6
Duration of glaucoma treatment (yrs)
Fig. 2. Visual field defects and duration of glaucoma treatment.
953
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara
Table 1. Endothelial cell density in uniocular capsular glaucoma.
I Field
Cell count/mmZ
defect in glaucoma eye 2467 2368 2608
14.4 11.5 11.1
+ +
65
2111 2095 2318
70 75 73
2732 2178 2650
3064 2385 2857
10.8 8.7 7.2
+
60 59 61
3171 2178 3146
3420 2343 3312
7.2 7.0 5.0
-
82 72 63
1739 2650 1987
1822 2774 2070
4.6 4.5 4.0
63 74 71
2525 2484 2263
2608 2567 2318
3.0 3.0 2.4
81 80 68
2443 2567 2070
2484 2542 2070
0 0 0
70 69 69
2318 1904 2484
2318 1904 2484
0 0 0
-
69 69 68
2194 2111 2484
2194 2070 2484
0 0 0
-
12 10 1
67 62 61
2732 2608 2277
2708 2542 2153
0 -3 -6
+ +
1 3 4
70 59
*
**
Duration of treatment (months)
Exfoliation positive also in the normotensive fellow eye. No treatment.
954
-
+ + +
-
+ + + -
18" 12 12 6 4 5** 12 36 2" 12" 72 3"" 24 24* 5'
1 12 60 3" 36 24"
Endothetiat Cells in Gafisular Glaucoma
B
Fig. 3. Large endothelial cells in glaucoma eye (Fig. 3 A ) compared with the normal endothelium of the healthy fellow eye of the same patient (Fig. 3 B). x 370.
Results Endothelial cell density
We photographed with a specular microscope endothelial cells of the central cornea of both eyes of 27 patients with unilateral capsular glaucoma. We calculated the endothelial cell densities of both the glaucomatous eyes and the contralateral healthy eyes of the same patients which served as controls. The endothelial cell density was lower in the glaucomatous than in the control eye of 15 of the 27 patients (Table I). Ten patients had the same cell count in the affected and in the control eye. There were two cases in which the cell density was lower in the normotensive than in the glaucomatous eye (3 and 6 per cent). The highest difference betweem the glaucomatous and control eyes was 14.4 per cent. The mean cell count of the glaucomatous eyes was 2386/mm2 and of the control eyes 2516lmm2. The difference was 5.2 per cent. 955
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara
As the comparison was made between the eyes of the same subject, personal factors affecting endothelial cell density can be disregarded. Statistically, 15 patients displayed a decrease in cell density in the glaucomatous eye, no difference was seen in 10 cases and two eyes with glaucoma had a higher cell density than the fellow eye. Although the material is fairly small, the lowered cell density of 15 glaucomatous eyes and only two higher densities in the healthy eyes confirms with statistical significance the direction of the difference (2 P < 0.01, sign test). Correlation with the clinical picture
In seven patients exfoliation was seen also in the normotensive control eye. The average cell density of the glaucoma eyes of these patients was 2364/mm2 and of the control eyes 24701mmZ. The difference is 4.3 per cent. Medication had not yet been commenced in two cases at the time of photography; the mean cell count of these glaucoma eyes was 2319/mm*, v c f b 2464/mm2 for the control eyes. The difference is 5.6 per cent. Cell size and morphology varied individually. Some patients displayed distinctly greater variation between the cells in the affected eyes and a couple of very large cells were even seen (Fig. 3). Comparison of the 15 cases which showed a lowered endothelial cell density with the 12 cases in which this change was not observed revealed that there was no correlation with the following parameters:
- intraocular pressure on admission or a pressure difference between the affected and the control eye; - variations of the diurnal curve;
-the C value or Po/C ratio; - duration of the glaucoma after admission, although the pressures were highly resistant to medical treatment; - visual field defect.
Discussion The patients of our series were selected in such a way that one eye had capsular glaucoma plus elevated intraocular pressure and the fellow eye had normal pressure. This made it possible to disregard individual qualities such as age etc., and compare only the two eyes of the same patient. The control material thus mainly differed from the investigation material only in the intraocular pressure. W e observed in the cases of uniocular glaucoma a statistically significant 956
Endothelial Cells in Capsular Glaucoma
decrease in endothelial cell density in the glaucomatous eyes compared with the healthy fellow eyes. The reason for this reduction in cell density was evidently the elevated intraocular pressure. Exfoliation and medication might be other factors reducing the endothelial cell density in our investigation material. I t is worthy of note that seven patients also displayed exfoliation in the control eye without elevated intraocular pressure. The cell count of the affected eyes of these patients was mostly smaller than that of the control eyes, which argues against the role of exfoliation in the lowering of the endothelial cell density. Moreover, it is worth stressing that no glaucoma medication had been instituted in two cases at the time of photography, and yet the cell density of their glaucoma eyes was similarly lowered. In addition, the decrease of endothelial cell density was not correlated with the duration of glaucoma treatment (Table I). These facts do not argue for the role of glaucoma medication in the lowering of the endothelial cell density. It seems evident that uniocular capsular glaucoma is a most suitable subject for an in vivo study with a specular microscope of the effects on the endothelium of long-lasting intraocular pressure. Interestingly, our results support the conclusions made by Irvine (1956) with other methods. Irvine studied 47 enucleated glaucomatous eyes and observed thinning of the endothelial cells. The cell count per unit of area was generally reduced. The detrimental effect of a short-term increase in intraocular pressure on the endothelial cells of the cornea in animal experiments on the Vervet monkey has also been reported (Svedberg 1975). Th e control eye appeared morphologically normal, but under higher pressure (33-44 mmHg) the eye revealed thinning of the corneal endothelial cells and changes in the ultrastructure such as vacuolisation, pyknosis and exkaryocytosis. Decreasing endothelial cell density and morphological variations in the endothelial cells in the glaucomatous eye did not correlate with the duration of the glaucoma or with its signs. This may be due partly to the paucity of our matepial, and partly to still unknown factors. Studies to establish the causal relationship are in progress.
References Becker B. & Shaffer R. N. (1976) Becker-Shaffer’sDiagnosis and Therapy of the Glaucomas. 4th ed. By A. E. Kolker and J. Hetherington, Jr. Mosby, Saint Louis, pp. 220-223.
Bourne W. M. & Kaufman H. E. (1976) Specular microscopy of human corneal endothelium in vivo. Amer. /. Ophthal. 81, 319-323. 957
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara Garner L. L. (1965) Tonography and the Glaucomas. Thomas, Springfield, Illinois. Irvine A. R., Jr. (1956) The role of endothelium in bullous keratopathy. Arch. Ophthal. (Chicago) 56, 338-351. Kaufman H. E., Capella J. A. & Robbins J. E. (1966) The human corneal endothelium. Amer. J. Ophthal. 61, 835-841 Laing R. A., Sandstrom M. M. & Leibowitz H. M. (1975) In vivo photomicrography of the corneal endothelium. Arch. Ophthal. (Chicago) 93, 143-145. Maurice D. M. (1968) Cellular membrane activity in the corneal endothelium of the eye. Experientia (Basel) 24, 1094-1095. Stocker F. W. (1971) The EndotheZium of the Cornea and Its Clinical ImpZications, 2nd. ed. Thomas, Springfield, Illinois, pp. 13-16. Svedbergh B. (1975) Effects of artificial intraocular pressure elevation on the corneal endothelium in the vervet monkey. Actn ophthal. (Kbh.) 53, 839-855. Author’s address: Antti Vannas, M.D., The University Eye Clinic, University of Helsinki, 00290, Helsinki 29, Finland.
958
From the University Eye Clinic (Head: Salme Vannas), University of Helsinki, Helsinki, Finland
ENDOTHELIAL CELLS IN CAPSULAR GLAUCOMA BY ANTTI VANNAS, KlRSl SETXLA and PEKKA RUUSUVAARA
The clinical specular microscope has made it possible to study corneal endothelial cells in vivo. In this study we report f o r the first time cell densities of unilateral glaucoma patients compared to the normotensive control eyes of the same patient. The corneal endothelium of 27 unilateral capsular glaucoma patients was photographed with a clinical specular microscope. The endothelial cell density was lower in the affected eye than in the normotensive fellow eye in 15 cases. In 10 patients the cell density was the same in both eyes. In two cases the glaucoma eye had a higher density than the fellow eye. Comparison of the above groups showed a statistical difference in the number of glaucoma eyes with a lower cell density (15 lower against 2 higher). The endothelial cell density could not be correlated with the duration of treatment or severity of the glaucoma.
Key words: glaucoma, capsular - pseudo-exfoliation - exfoliation - fibrillopathia epitheliocapsularis - endothelial cell density - endothelial cell loss - clinical specular microscope.
Slit-lamp magnification is not sufficient for the study of endothelial cells. Only with the specular microscope can the size, morphology and quantity of endothelial cells be examined in vivo (Maurice 1968; Laing et al. 1975; Bourne & Kaufman 1976). The endothelial cell count of a young subject has been established to be around 500 000 (3300/mm*) by means of the specular microscope. The number of endothelial cells decreases with age, and the endothelial cell Received May 5 , 1977.
95 1 61*
Antti Vannas, Kirsi Setalii, Pekka Ruusuvaara Number of
patients
,
55-59 60-64 65-69 70-74 75-79 80-84
A g e group ( m i
Fig. I. Age and sex distribution of patients.
density of a subject aged 60 years is approximately 2600/mm2 (Bourne & Kaufman 1976). The endothelial cell count may also decrease after trauma when the cell regeneration capacity is either lacking or very limited (Kaufman et al. 1966; Stocker 1971; Bourne & Kaufman 1976). The purpose of this work was to study the effects of increased intraocular pressure on the endothelial cells of glaucoma patients, since earlier information on the subject is very meagre. In Irvine’s (1956) study of enucleated glaucomatous eyes, thinning of endothelial cells was demonstrated in light microscopy sections and in places the endothelium was missing.
Material and Methods The material consisted of 27 patients with uniocular capsular glaucoma which was diagnosed according to Becker & Shaffer (1976). All of them had unilateral glaucoma and a distinctly elevated intraocular pressure prior to glaucoma therapy. Twenty-five patients were undergoing pilocarpine treatment or other glaucoma therapy already at the time of photography. Treatment was instituted after endothelial photography in two recently diagnosed cases. Patients on whom an intrabulbar operation had been performed were excluded from the material because of potential surgical trauma to the endothelium. The normotensive eyes of each patient constituted the control series. The intraocular pressures were measured by Goldmann’s applanation tono952
Endothelial Cells in Capsular Glaucoma
meter, the visual fields were studied by Goldmann perimeter and the central visual field by Friedmann’s analyser. Tonography was performed as described by Garner (1965) by a trained person. The patients’ ages and sex distribution are presented in Fig. 1. The age range was 59-82 years. Women were in the majority. Fig. 2 shows the duration of glaucoma treatment and presence of possible visual field defects. The endothelial cells were photographed with a specular microscope (Seyber Inc). Several pictures, five 011 average, were taken of the central cornea of both eyes of each patient. The morphology and size of the endothelial cells were analysed by projecting the negative onto a screen. The density of the endothelial cells was determined by counting the number visible in the specular area. The magnification of the specular microscope was calculated by photographing from a standardised glass plate the calibration lines with an objective working distance which corresponds to the normal thickness of the cornea. The final magnification in analysing the cells from the screen was x 730. The cells were counted from three photographs and their mean was entered as the result. An area corresponding to 0.012 mm2 on the endothelium was calculated in each photograph and the result was expressed as the number of cells per mm2.
@ = field defect
c]
= no
field defect
n
1-2
2-3
3-4
4-5
5-6
Duration of glaucoma treatment (yrs)
Fig. 2. Visual field defects and duration of glaucoma treatment.
953
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara
Table 1. Endothelial cell density in uniocular capsular glaucoma.
I Field
Cell count/mmZ
defect in glaucoma eye 2467 2368 2608
14.4 11.5 11.1
+ +
65
2111 2095 2318
70 75 73
2732 2178 2650
3064 2385 2857
10.8 8.7 7.2
+
60 59 61
3171 2178 3146
3420 2343 3312
7.2 7.0 5.0
-
82 72 63
1739 2650 1987
1822 2774 2070
4.6 4.5 4.0
63 74 71
2525 2484 2263
2608 2567 2318
3.0 3.0 2.4
81 80 68
2443 2567 2070
2484 2542 2070
0 0 0
70 69 69
2318 1904 2484
2318 1904 2484
0 0 0
-
69 69 68
2194 2111 2484
2194 2070 2484
0 0 0
-
12 10 1
67 62 61
2732 2608 2277
2708 2542 2153
0 -3 -6
+ +
1 3 4
70 59
*
**
Duration of treatment (months)
Exfoliation positive also in the normotensive fellow eye. No treatment.
954
-
+ + +
-
+ + + -
18" 12 12 6 4 5** 12 36 2" 12" 72 3"" 24 24* 5'
1 12 60 3" 36 24"
Endothetiat Cells in Gafisular Glaucoma
B
Fig. 3. Large endothelial cells in glaucoma eye (Fig. 3 A ) compared with the normal endothelium of the healthy fellow eye of the same patient (Fig. 3 B). x 370.
Results Endothelial cell density
We photographed with a specular microscope endothelial cells of the central cornea of both eyes of 27 patients with unilateral capsular glaucoma. We calculated the endothelial cell densities of both the glaucomatous eyes and the contralateral healthy eyes of the same patients which served as controls. The endothelial cell density was lower in the glaucomatous than in the control eye of 15 of the 27 patients (Table I). Ten patients had the same cell count in the affected and in the control eye. There were two cases in which the cell density was lower in the normotensive than in the glaucomatous eye (3 and 6 per cent). The highest difference betweem the glaucomatous and control eyes was 14.4 per cent. The mean cell count of the glaucomatous eyes was 2386/mm2 and of the control eyes 2516lmm2. The difference was 5.2 per cent. 955
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara
As the comparison was made between the eyes of the same subject, personal factors affecting endothelial cell density can be disregarded. Statistically, 15 patients displayed a decrease in cell density in the glaucomatous eye, no difference was seen in 10 cases and two eyes with glaucoma had a higher cell density than the fellow eye. Although the material is fairly small, the lowered cell density of 15 glaucomatous eyes and only two higher densities in the healthy eyes confirms with statistical significance the direction of the difference (2 P < 0.01, sign test). Correlation with the clinical picture
In seven patients exfoliation was seen also in the normotensive control eye. The average cell density of the glaucoma eyes of these patients was 2364/mm2 and of the control eyes 24701mmZ. The difference is 4.3 per cent. Medication had not yet been commenced in two cases at the time of photography; the mean cell count of these glaucoma eyes was 2319/mm*, v c f b 2464/mm2 for the control eyes. The difference is 5.6 per cent. Cell size and morphology varied individually. Some patients displayed distinctly greater variation between the cells in the affected eyes and a couple of very large cells were even seen (Fig. 3). Comparison of the 15 cases which showed a lowered endothelial cell density with the 12 cases in which this change was not observed revealed that there was no correlation with the following parameters:
- intraocular pressure on admission or a pressure difference between the affected and the control eye; - variations of the diurnal curve;
-the C value or Po/C ratio; - duration of the glaucoma after admission, although the pressures were highly resistant to medical treatment; - visual field defect.
Discussion The patients of our series were selected in such a way that one eye had capsular glaucoma plus elevated intraocular pressure and the fellow eye had normal pressure. This made it possible to disregard individual qualities such as age etc., and compare only the two eyes of the same patient. The control material thus mainly differed from the investigation material only in the intraocular pressure. W e observed in the cases of uniocular glaucoma a statistically significant 956
Endothelial Cells in Capsular Glaucoma
decrease in endothelial cell density in the glaucomatous eyes compared with the healthy fellow eyes. The reason for this reduction in cell density was evidently the elevated intraocular pressure. Exfoliation and medication might be other factors reducing the endothelial cell density in our investigation material. I t is worthy of note that seven patients also displayed exfoliation in the control eye without elevated intraocular pressure. The cell count of the affected eyes of these patients was mostly smaller than that of the control eyes, which argues against the role of exfoliation in the lowering of the endothelial cell density. Moreover, it is worth stressing that no glaucoma medication had been instituted in two cases at the time of photography, and yet the cell density of their glaucoma eyes was similarly lowered. In addition, the decrease of endothelial cell density was not correlated with the duration of glaucoma treatment (Table I). These facts do not argue for the role of glaucoma medication in the lowering of the endothelial cell density. It seems evident that uniocular capsular glaucoma is a most suitable subject for an in vivo study with a specular microscope of the effects on the endothelium of long-lasting intraocular pressure. Interestingly, our results support the conclusions made by Irvine (1956) with other methods. Irvine studied 47 enucleated glaucomatous eyes and observed thinning of the endothelial cells. The cell count per unit of area was generally reduced. The detrimental effect of a short-term increase in intraocular pressure on the endothelial cells of the cornea in animal experiments on the Vervet monkey has also been reported (Svedberg 1975). Th e control eye appeared morphologically normal, but under higher pressure (33-44 mmHg) the eye revealed thinning of the corneal endothelial cells and changes in the ultrastructure such as vacuolisation, pyknosis and exkaryocytosis. Decreasing endothelial cell density and morphological variations in the endothelial cells in the glaucomatous eye did not correlate with the duration of the glaucoma or with its signs. This may be due partly to the paucity of our matepial, and partly to still unknown factors. Studies to establish the causal relationship are in progress.
References Becker B. & Shaffer R. N. (1976) Becker-Shaffer’sDiagnosis and Therapy of the Glaucomas. 4th ed. By A. E. Kolker and J. Hetherington, Jr. Mosby, Saint Louis, pp. 220-223.
Bourne W. M. & Kaufman H. E. (1976) Specular microscopy of human corneal endothelium in vivo. Amer. /. Ophthal. 81, 319-323. 957
Antti Vannas, Kirsi Setala, Pekka Ruusuvaara Garner L. L. (1965) Tonography and the Glaucomas. Thomas, Springfield, Illinois. Irvine A. R., Jr. (1956) The role of endothelium in bullous keratopathy. Arch. Ophthal. (Chicago) 56, 338-351. Kaufman H. E., Capella J. A. & Robbins J. E. (1966) The human corneal endothelium. Amer. J. Ophthal. 61, 835-841 Laing R. A., Sandstrom M. M. & Leibowitz H. M. (1975) In vivo photomicrography of the corneal endothelium. Arch. Ophthal. (Chicago) 93, 143-145. Maurice D. M. (1968) Cellular membrane activity in the corneal endothelium of the eye. Experientia (Basel) 24, 1094-1095. Stocker F. W. (1971) The EndotheZium of the Cornea and Its Clinical ImpZications, 2nd. ed. Thomas, Springfield, Illinois, pp. 13-16. Svedbergh B. (1975) Effects of artificial intraocular pressure elevation on the corneal endothelium in the vervet monkey. Actn ophthal. (Kbh.) 53, 839-855. Author’s address: Antti Vannas, M.D., The University Eye Clinic, University of Helsinki, 00290, Helsinki 29, Finland.
958
