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Discussion of Presentation by Dr Gilbert W. Cleasby
DISCUSSION OF PRESENTATION BY DR GILBERT W. CLEASBY GuY E. KNOLLE, JR, MD JOHNNY JUSTICE, JR, FOPS and
WILLIAM D. SPEARS, MA HOUSTON, TEXAS KELMAN phacoemulsification (KPE) has added a new dimension to cataract surgery. New concepts derived from this procedure have given surgeons a better overall understanding of cataract methodology. Dr Cleasby has clearly delineated the advantages and disadvantages of KPE. A considerable amount of interest and concern has been expressed over the outcome of the first 50 cases a beginning KPE surgeon performs. I would like to highlight several aspects of Dr Cleasby's discussion using a fourto five-year follow-up study of my first 50 consecutive KPE operations as compared to 50 consecutive intracapsular cataract extractions (ICCE) I performed during the same period of time (from 1972 to 1974) (Tables 1 and 2). Even though statistics are not applicable for small series, of the original 100 eyes studied, 53 were available for a four-year follow-up. In this followup study, there were 25 KPE opera-
Submitted for publication Oct 26, 1978. Reprint requests to 4126 S.W. Freeway #1700, Houston, TX 77027 (Dr Knolle).
tions and 26 ICCE operations. The median age of the KPE patients was 68 years and the ICCE patients was 73 years at the time of surgery. For qualitative rather than quantitative assessment of KPE in light of Dr Cleasby's discussion, I will rely on personal surgical experience with KPE over the past six years and clinical observations of my patients and those of other KPE surgeons. In this series of 53 eyes, 52% of the KPE eyes had 20/20 vision at the end of four years; only 23% of the ICCE eyes achieved this level. Furthermore, in this small study group, 100% of the KPE eyes saw 20/40 or better, while 88% of the ICCE eyes did as well (Table 3). To explain this discrepancy in visual acuity, several parameters were' examined. No clinical corneaedema could be demonstrated in either group. Furthermore, visual acuity had no statistically significant relationship to endothelial cell count in any of the eyes (Fig 1). Examination of the macula by fluorescein angiography was the most revealing parameter. There was an increased incidence of macular pathology in the older intracapsular group (Table 4).
1975
KNOLLE ET AL
1976
TABLE 1 4-YEAR FOLLOW-UP OF 47 PATIENTS* OPERATED ON BETWEEN 1972-1974 NO. EYES
KPE
25 26 2 53
ICCE PECE, UECE Total *Median age, 70 years.
When the age difference between these two groups of patients is considered, these data are in agreement with Dr Cleasby and the Academy study. The visual acuity in KPE is at least as good as that following ICCE. The most common, serious operative complication of cataract surgery is vitreous disturbance. As Dr Cleasby has pointed out, vitr~ou~ loss in the presence of a small mCIsion is a less serious clinical entity in terms of intraoperative management and postoperative sequelae. In both instances of small incision vitreous loss in this series of eyes, 20/20 vision was obtained (Table 5). Retinal detachment occurred only twice in this series. In both instances it followed large incision
OPHTH AAO
TABLE 3 4-YEAR FOLLOW-UP IN 53 EYES VISUAL ACUITY 20/20t 20/25+ 20/40t
KPE
ICCE
52% 80% 100%
23% 50% 88%
vitreous loss. Retinal detachment and its relationship to extracapsular surgery will be discussed in detail later. Secondary opacification of the posterior capsule is a well-recognized complication of KPE and other types of extracapsular surgery. Before long-term follow-up studies were available, it was generally estimated that opacification would occur in as few as 15% or 20% of cases. It is now apparent that the incidence of opacification continues to progress with time. In this series of 29 patients with a four- to six-year follow-up, the incidence of visually significant secondary opacification of the posterior capsule was 45%. Despite the frequency of this occurrence, capsular opacification is easily managed by secondary polishing and/ or discission.
TABLE 4 MACULAR EXAMINATION BY FLUORESCEIN ANGIOGRAPHY TABLE 2 PATIENTS NOT AVAILABLE FOR FoLLOW-UP NO. NO. PATIENTS EYES Deceased Refused cooperation Lost to follow-up Total
12 20
14 25
7
8
39
47
Normal Cystoid macular edema Macular degeneration Other (as RPED*) Total Median age of patient
KPE
ICCE
22 0 2 1 25 68
17 2 3 4 26 73
*RPED, retinal pigment epithelial damage.
1977
DISCUSSION
VOLUME 86 NOVEMBER 1979
TABLE
5
COMPLICATIONS NO. EYES
KPE
NO. EYES
Small incision VA 20/20
2
Vitreous Loss Small incision None
0
2
Large incision VA 20/25 20/200
1 1
Large incision VA 20/25 20170
ICCE
1
Large incision VA 20/25
2
Total
5
Total
RetiTULl Detachment Large incision VA 20/200
1
The relationship between KPE and corneal endothelial cell damage has been a serious concern of ophthalmic surgeons since the pro-
2
cedure was first introduced. In our study of 53 eyes undergoing both KPE and ICCE in essentially equal numbers, there was no clinical cor-
50
40
V"l
LL.I
>LL.I
30
u... 0 I-
z
LL.I
u a::
LL.I Q..
(20/20) 24
20
(20/25) 17 (20/40 or worse) 6
10
(20/30) 16 0
500-999
1000-1499
1500-1999
REMAINING CELLS
2000-2499
2500 or more
Fig 1.-Visual acuity has no statistical relationship to endothelial cell count.
KNOLLE ET AL
1978
OPHTH AAO
40
30 Vl LLJ
>LLJ u.
0 I-
z
1
20
LLJ
,J , ,
u
0:::: LLJ
0....
10
0
500-999
I
1000-1499
REMAINING CELLS
KPE
1500-1999 R
2000-2499 =
•
05
2500 or more p ~. 36
Fig 2.-There is no significant statistical difference between corneal endothelial cells remaining after KPE when compared to ICCE.
neal edema in either group. Furthermore, an analysis of corneal endothelial cells remaining four to six years after KPE compared to ICCE revealed no statistically significant difference (Fig 2). Comparing endothelial cell count in fellow eyes having undergone KPE, ICCE, PECE (Planned extracapsular cataract extraction), UECE (Unplanned extracapsular cataract extraction), and no surgery, several observations can be made: 1. There was no significant statistical difference in the numbers of endothelial cells lost by type of procedure.
2. There was no significant statistical difference in the number
of endothelial cells remaining after surgery in a one time sampling in a six-year period. 3. There was no significant change in the mean cell population that could be demonstrated when eyes that were less than four years postoperative were compared to eyes that were over four years. There are certain clinical considerations that are not easily analyzed in a quantitative fashion but are, nonetheless, quite significant in evaluating cataract surgery. The use of a small incision in addition to carefully monitored aspiration and irrigation insures the KPE surgeon of strict control of the anterior segment during surgery. Important anatomic relation-
VOLUME 86 NOVEMBER 1979
DISCUSSION
ships are further protected during the procedure as well as in the postoperative state by preservation of the posterior capsule. While this strict control of the surgical environment is desirable in every intraocular procedure, it is of special significance in certain situations. By maintaining the anterior segment during removal of the lenticular opacity, scleral collapse and secondary vitreous disturbances are avoided in the high myope. In addition, KPE does not require a large incision that could be potentially damaging to a previously constructed filtering bleb or penetrating keratoplasty. Mter surgery, preservation of the posterior capsule contains and supports the vitreous. The posterior capsule protects the retina of the high myope from vitreous traction,
1979
the filtering bleb of the glaucoma patient from vitreous occlusion, and the endothelium of a patient with penetrating keratoplasty from vitreous touch. Finally, as Dr Cleasby has alluded to, KPE should be given consideration in cases wherein intraocular lens implantation is anticipiated. The lasting success of any intraocular lens implantation is dependent to a large degree on the implant stability within the eye. The posterior capsule, as preserved in KPE, in conjunction with the ciliary body or the iris provides an ideal structure for support and fixation of an intraocular lens. This support is not available to the intracapsular surgeon. Additionally, when secondary intraocular lens implantation is performed, the posterior capsule provides a protective barrier against vitreous disturbance.
WILLIAM D. SPEARS, MA HOUSTON, TEXAS KELMAN phacoemulsification (KPE) has added a new dimension to cataract surgery. New concepts derived from this procedure have given surgeons a better overall understanding of cataract methodology. Dr Cleasby has clearly delineated the advantages and disadvantages of KPE. A considerable amount of interest and concern has been expressed over the outcome of the first 50 cases a beginning KPE surgeon performs. I would like to highlight several aspects of Dr Cleasby's discussion using a fourto five-year follow-up study of my first 50 consecutive KPE operations as compared to 50 consecutive intracapsular cataract extractions (ICCE) I performed during the same period of time (from 1972 to 1974) (Tables 1 and 2). Even though statistics are not applicable for small series, of the original 100 eyes studied, 53 were available for a four-year follow-up. In this followup study, there were 25 KPE opera-
Submitted for publication Oct 26, 1978. Reprint requests to 4126 S.W. Freeway #1700, Houston, TX 77027 (Dr Knolle).
tions and 26 ICCE operations. The median age of the KPE patients was 68 years and the ICCE patients was 73 years at the time of surgery. For qualitative rather than quantitative assessment of KPE in light of Dr Cleasby's discussion, I will rely on personal surgical experience with KPE over the past six years and clinical observations of my patients and those of other KPE surgeons. In this series of 53 eyes, 52% of the KPE eyes had 20/20 vision at the end of four years; only 23% of the ICCE eyes achieved this level. Furthermore, in this small study group, 100% of the KPE eyes saw 20/40 or better, while 88% of the ICCE eyes did as well (Table 3). To explain this discrepancy in visual acuity, several parameters were' examined. No clinical corneaedema could be demonstrated in either group. Furthermore, visual acuity had no statistically significant relationship to endothelial cell count in any of the eyes (Fig 1). Examination of the macula by fluorescein angiography was the most revealing parameter. There was an increased incidence of macular pathology in the older intracapsular group (Table 4).
1975
KNOLLE ET AL
1976
TABLE 1 4-YEAR FOLLOW-UP OF 47 PATIENTS* OPERATED ON BETWEEN 1972-1974 NO. EYES
KPE
25 26 2 53
ICCE PECE, UECE Total *Median age, 70 years.
When the age difference between these two groups of patients is considered, these data are in agreement with Dr Cleasby and the Academy study. The visual acuity in KPE is at least as good as that following ICCE. The most common, serious operative complication of cataract surgery is vitreous disturbance. As Dr Cleasby has pointed out, vitr~ou~ loss in the presence of a small mCIsion is a less serious clinical entity in terms of intraoperative management and postoperative sequelae. In both instances of small incision vitreous loss in this series of eyes, 20/20 vision was obtained (Table 5). Retinal detachment occurred only twice in this series. In both instances it followed large incision
OPHTH AAO
TABLE 3 4-YEAR FOLLOW-UP IN 53 EYES VISUAL ACUITY 20/20t 20/25+ 20/40t
KPE
ICCE
52% 80% 100%
23% 50% 88%
vitreous loss. Retinal detachment and its relationship to extracapsular surgery will be discussed in detail later. Secondary opacification of the posterior capsule is a well-recognized complication of KPE and other types of extracapsular surgery. Before long-term follow-up studies were available, it was generally estimated that opacification would occur in as few as 15% or 20% of cases. It is now apparent that the incidence of opacification continues to progress with time. In this series of 29 patients with a four- to six-year follow-up, the incidence of visually significant secondary opacification of the posterior capsule was 45%. Despite the frequency of this occurrence, capsular opacification is easily managed by secondary polishing and/ or discission.
TABLE 4 MACULAR EXAMINATION BY FLUORESCEIN ANGIOGRAPHY TABLE 2 PATIENTS NOT AVAILABLE FOR FoLLOW-UP NO. NO. PATIENTS EYES Deceased Refused cooperation Lost to follow-up Total
12 20
14 25
7
8
39
47
Normal Cystoid macular edema Macular degeneration Other (as RPED*) Total Median age of patient
KPE
ICCE
22 0 2 1 25 68
17 2 3 4 26 73
*RPED, retinal pigment epithelial damage.
1977
DISCUSSION
VOLUME 86 NOVEMBER 1979
TABLE
5
COMPLICATIONS NO. EYES
KPE
NO. EYES
Small incision VA 20/20
2
Vitreous Loss Small incision None
0
2
Large incision VA 20/25 20/200
1 1
Large incision VA 20/25 20170
ICCE
1
Large incision VA 20/25
2
Total
5
Total
RetiTULl Detachment Large incision VA 20/200
1
The relationship between KPE and corneal endothelial cell damage has been a serious concern of ophthalmic surgeons since the pro-
2
cedure was first introduced. In our study of 53 eyes undergoing both KPE and ICCE in essentially equal numbers, there was no clinical cor-
50
40
V"l
LL.I
>LL.I
30
u... 0 I-
z
LL.I
u a::
LL.I Q..
(20/20) 24
20
(20/25) 17 (20/40 or worse) 6
10
(20/30) 16 0
500-999
1000-1499
1500-1999
REMAINING CELLS
2000-2499
2500 or more
Fig 1.-Visual acuity has no statistical relationship to endothelial cell count.
KNOLLE ET AL
1978
OPHTH AAO
40
30 Vl LLJ
>LLJ u.
0 I-
z
1
20
LLJ
,J , ,
u
0:::: LLJ
0....
10
0
500-999
I
1000-1499
REMAINING CELLS
KPE
1500-1999 R
2000-2499 =
•
05
2500 or more p ~. 36
Fig 2.-There is no significant statistical difference between corneal endothelial cells remaining after KPE when compared to ICCE.
neal edema in either group. Furthermore, an analysis of corneal endothelial cells remaining four to six years after KPE compared to ICCE revealed no statistically significant difference (Fig 2). Comparing endothelial cell count in fellow eyes having undergone KPE, ICCE, PECE (Planned extracapsular cataract extraction), UECE (Unplanned extracapsular cataract extraction), and no surgery, several observations can be made: 1. There was no significant statistical difference in the numbers of endothelial cells lost by type of procedure.
2. There was no significant statistical difference in the number
of endothelial cells remaining after surgery in a one time sampling in a six-year period. 3. There was no significant change in the mean cell population that could be demonstrated when eyes that were less than four years postoperative were compared to eyes that were over four years. There are certain clinical considerations that are not easily analyzed in a quantitative fashion but are, nonetheless, quite significant in evaluating cataract surgery. The use of a small incision in addition to carefully monitored aspiration and irrigation insures the KPE surgeon of strict control of the anterior segment during surgery. Important anatomic relation-
VOLUME 86 NOVEMBER 1979
DISCUSSION
ships are further protected during the procedure as well as in the postoperative state by preservation of the posterior capsule. While this strict control of the surgical environment is desirable in every intraocular procedure, it is of special significance in certain situations. By maintaining the anterior segment during removal of the lenticular opacity, scleral collapse and secondary vitreous disturbances are avoided in the high myope. In addition, KPE does not require a large incision that could be potentially damaging to a previously constructed filtering bleb or penetrating keratoplasty. Mter surgery, preservation of the posterior capsule contains and supports the vitreous. The posterior capsule protects the retina of the high myope from vitreous traction,
1979
the filtering bleb of the glaucoma patient from vitreous occlusion, and the endothelium of a patient with penetrating keratoplasty from vitreous touch. Finally, as Dr Cleasby has alluded to, KPE should be given consideration in cases wherein intraocular lens implantation is anticipiated. The lasting success of any intraocular lens implantation is dependent to a large degree on the implant stability within the eye. The posterior capsule, as preserved in KPE, in conjunction with the ciliary body or the iris provides an ideal structure for support and fixation of an intraocular lens. This support is not available to the intracapsular surgeon. Additionally, when secondary intraocular lens implantation is performed, the posterior capsule provides a protective barrier against vitreous disturbance.