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Safety of trypan blue 1% and indocyanine green 0.5% in assisting visualization of anterior capsule during phacoemulsification in mature cataract
Safety of trypan blue 1% and indocyanine green 0.5% in assisting visualization of anterior capsule during phacoemulsification in mature cataract Chong Fai Chung, MRCSEd, Chan Chung Liang, FRCS, Jimmy S.M. Lai, FRCS, FRCOphth, Ernie S.F. Lo, MBBS, Dennis S.C. Lam, FRCS, FRCOphth Purpose: To evaluate the safety of trypan blue 1% and indocyanine green (ICG) 0.5% in assisting visualization of anterior capsule during phacoemulsification in mature cataract. Setting: Department of Ophthalmology, United Christian Hospital, Hong Kong, China. Methods: This prospective randomized clinical trial comprised 46 eyes with mature cataract receiving phacoemulsification and posterior chamber intraocular lens implantation. They were randomized into 3 groups (trypan blue, ICG, and control without stain). Visual acuity, endothelial cell count, corneal clarity, anterior chamber reaction, and intraocular pressure (IOP) were documented before surgery and 1 week, 1 month, and 3 months postoperatively. The absolute phaco time was also recorded. Results: There was no significant difference in absolute phaco time (P Z .17), mean endothelial cell loss (P Z .72 at 1 week, P Z .43 at 1 month, and P Z .60 at 3 months) and no significant correlation between the absolute phaco time and the change in endothelial cell count (P Z .50 at 1 week, P Z .10 at 1 month, and P Z .60 at 3 months) in the 3 groups. None of the patients had postoperative IOP greater than 21 mm Hg. All eyes had clear corneas and a quiet anterior chamber 3 months after surgery. Conclusion: Both trypan blue 1% and ICG 0.5% are safe for assisting visualization of the anterior capsule during phacoemulsification of mature cataract. J Cataract Refract Surg 2005; 31:938–942 ª 2005 ASCRS and ESCRS
P
hacoemulsification has several advantages over extracapsular cataract extraction (ECCE), including a smaller wound with less induced astigmatism and a shorter visual rehabilitation period. In mature cataract,
Accepted for publication September 14, 2004. From the Department of Ophthalmology (Chung, Liang, Lai), United Christian Hospital, Department of Ophthalmology (Lo), Tseung Kwan O Hospital, and Department of Ophthalmology and Visual Sciences (Lam), The Chinese University of Hong, Hong Kong SAR, China. No author has a financial or proprietary interest in any material or method mentioned. Reprint requests to Dr. Jimmy S.M. Lai, Department of Ophthalmology, United Christian Hospital, Hip Wo Street, Kwun Tong, Kowloon, Hong Kong SAR, China. E-mail: [email protected]. 2005 ASCRS and ESCRS Published by Elsevier Inc.
however, defined as totally opacified lens matter in the presence of normal anterior chamber depth precluding visualization of the red reflex, continuous curvilinear capsulorhexis (CCC) may be difficult. A poorly performed anterior capsulorhexis increases surgical risk in the later part of surgery. Trypan blue and indocyanine green (ICG) have been used as adjuncts for enhancing the visibility of the anterior capsule in cataract surgery.1–4 In vitro study of trypan blue toxicity on ocular tissues is not available. Indocyanine green (ICG) is a nontoxic tricarbocyanine and has been used for studying the choroidal circulation since 1970.5 Recently, ICG began to be used for peeling the internal limiting membrane during macular surgery.6 Both ICG and trypan blue selectively stain 0886-3350/05/$-see front matter doi:10.1016/j.jcrs.2004.12.046
VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
devitalized corneal endothelial cells.7,8 Indocyanine green was found to be nontoxic to rabbit endothelial cell function in perfusion studies.9 Exposure to ICG 0.5% of up to 3 minutes caused no adverse effect to the corneal endothelial function, ultrastructure, and viability in either human and rabbit corneas in vitro.9 The effects of ICG or trypan blue on intraocular structures in vivo have not been fully studied. The aim of this study was to assess the safety of trypan blue and ICG used as adjuncts for performing CCC in eyes with mature cataract having phacoemulsification.
a foldable acrylic intraocular lens (AcrySof MA30BA, Alcon) was implanted. The viscoelastic agent was completely aspirated. All the operations were performed by 1 of 2 surgeons (J.S.L., B.C.L.). The absolute phaco time in seconds was recorded. Chloramphenicol 0.5% and dexamethasone 0.1% (Neo-Dex) eyedrops were given to all patients for a period of 6 weeks. Follow-up was 1 day, 1 week, 1 month, and 3 months after surgery. Visual acuity, AC reaction, corneal clarity, and IOP were recorded. The endothelial cell count was measured at 1 week, 1 month, and 3 months. Nonparametric tests were used for statistical analysis. The Kruskal-Wallis test was used for analyzing differences among the 3 groups. Spearman’s rho was used for calculating the level of correlation between 2 variables.
Patients and Methods This prospective randomized clinical trial included 46 eyes of 46 consecutive patients with mature cataract who had phacoemulsification and posterior chamber intraocular lens implantation between June 2002 and March 2003. Exclusion criteria included preexisting corneal diseases such as cornea guttata or scar, history of uveitis, glaucoma, and intraoperative complications of posterior capsular tear and vitreous loss. The study was approved by the Research Ethics Committee of the United Christian Hospital, Hong Kong. Preoperative assessment included visual acuity, endothelial cell count (measured by an assigned optometrist with the Konan Specular Microscopy Noncon Robo SP 6000) and intraocular pressure (IOP) measurements. After providing informed consent, patients were randomly assigned (SD) using a randomization table into 1 of the 3 groups: (1) trypan blue 1% (undiluted Vision Blue solution), (2) ICG 0.5% (25 mg Diagnogreen in 5 mL Aqsia solution), and (3) control group without capsular stain. One hour before surgery, the pupils were dilated with tropicamide 0.5% and phenylephrine 0.5% (Mydrin-P) applied 3 times at 10-minute intervals. Either topical or regional anesthesia was used. The trypan blue was a premixed commercial preparation. The ICG was prepared by dissolving 25 mg of the powder in 5 mL of sterile water; 1 mL of the dissolved ICG was aspirated and mixed with 9 mL of sterile Aqsia solution (Chauvin Opsia). A superior 3.2 mm clear corneal wound was constructed. Air was injected into the anterior chamber (AC) through a paracentesis wound to displace the aqueous; 0.5 ml of either trypan blue or ICG was then injected and left in the AC for 2 minutes. The stain was removed with Aqsia solution. In the control group, no capsule stain was used. Sodium chondroitin sulfate–sodium hyaluronate (Viscoat) was then injected into the AC, and anterior CCC was performed using a Utrata forceps followed by hydrodissection. Stop-and-chop phacoemulsification was performed using the Millennium CX 6000 (Bausch & Lomb Surgical). After the nucleus and cortex were removed, sodium hyaluronate (Provisc) was injected in the capsular bag, and
Results The study included 49 patients. In all 3 groups, anterior CCC was completed without tear. One patient in the trypan blue group required conversion to ECCE, and 2 patients in the control group had PC tear with vitreous loss. These 3 patients were excluded, leaving 46 patients for data analysis. Mean age was 66.4 years G 10.0 years (10 women, 4 men) in the trypan blue group, 73.1 G 8.8 years in the ICG group (7 women, 10 men), and 71.5 G 9.6 years in the control group (8 women, 7 men) (P Z .15). Seven patients (2 in the trypan blue, 3 in the ICG, and 2 in the control groups) defaulted the 3-month follow-up. The percentage of patients with preoperative visual acuity of counting fingers or less was 100%, 82.4%, and 80.0% in the trypan blue, ICG, and control groups, respectively. Three months postoperatively, 78.6%, 41.2%, and 46.7% of patients in the respective groups had a best corrected visual acuity of R.5. Table 1 summarizes the characteristics of the patients in the 3 groups. There was no significant difference in the absolute phaco time between the 3 groups: 18.0 G 5.1 seconds, 22.3 G 7.8 (SD) seconds, and 22.3 G 8.4 seconds, respectively (P Z .17). There was no significant difference in the mean endothelial cell loss (difference between the preoperative and the postoperative endothelial cell counts) in the 3 groups (trypan blue, ICG, and control groups, respectively: 510 G 634 cells/mm2, 510 G 927 cells/mm2, and 707 G 685 cells/mm2 at 1 week postoperative, P Z .72; 657 G 558 cells/mm2, 592 G 678 cells/mm2, and 950 G 682 cells/mm2 at
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
Table 1.
Characteristics in the 3 groups.
Characteristic
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value*
Mean age (years)
66.4 G 10.0
73.1 G 8.8
71.5 G 9.6
.15
Sex
10 Female:4 Male
7 Female:10 Male
8 Female:7 Male
—
Patients (%) with visual acuity % counting finger
100.0
82.4
80.0
—
Preoperative IOP (mm Hg)
12.8 G 2.6
12.1 G 2.7
13.3 G 4.0
.76
Mean phaco time (seconds)
18.0 G 5.1
22.3 G 7.8
22.3 G 8.4
.17
Means GSD *Kruskal-Wallis test.
1 month postoperative, P Z .43; and 526 G 404 cells/ mm2, 718 G 655 cells/mm2, and 658 G 614 cells/mm2 at 3 months postoperative, P Z .60; Table 2). No correlation between phaco energy and mean endothelial cell loss at 1 week (correlation coefficient 0.11, P Z .50), 1 month (correlation coefficient 0.25, P Z .10), or 3 months (correlation coefficient 0.13, P Z .46) after phacoemulsification was found in any group. The mean postoperative IOPs for the 3 groups are shown in Table 3. There was no significant difference in mean IOP between the 3 groups at various times of follow-up. No patient had IOP greater than 21 mm Hg at any of the scheduled postoperative visits, and none required IOP-lowering medication. None of the patients had excessive postoperative AC reaction in the form of fibrinous exudation, and none required prolonged use of topical steroid for control of AC inflammation. Table 2.
Two patients in the ICG group had mild corneal haziness 1 month after the operation, but clarity returned at 3 months.
Discussion A properly performed anterior CCC is an important step in the success of phacoemulsification. The red reflex in eyes with a white mature cataract is poor, and visualization of the anterior capsule is difficult. Trypan blue and ICG had been used for staining the anterior capsule for CCC and were found to be safe.1–4 A high incidence of retinal pigment epithelial changes within the macula after ICG-assisted macula hole surgery has been reported.10 In a study by Horiguchi and coauthors,1 ICG 0.5% was used to stain the anterior capsule for CCC in phacoemulsification in white cataract. They found no significant difference in the endothelial cell count of eyes that had been stained
Mean endothelial cell count and postoperative endothelial cell loss in the 3 groups.
Examination
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value, Mean
Pre-phacoemulsification Mean endothelial cell count (mmÿ2)
2525 G 319
2213 G 393
2574 G 466
—
1995 G 639
1726 G 858
1870 G 702
.72
1 week post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
510 G 634 (20.2)
510 G 927 (23.0)
707 G 685 (27.5)
1 month post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
1868 G 627 657 G 558 (26.0)
1621 G 615 592 G 678 (26.7)
1629 G 671
.43
950 G 682 (36.9)
3 months post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
940
2055 G 344
1535 G 651
1897 G 726
526 G 404 (20.8)
718 G 655 (32.4)
658 G 615 (25.6)
(n Z 10)
(n Z 14)
(n Z 13)
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
Table 3.
Postoperative mean IOP (mm Hg) in the 3 groups.
Examination
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value*
1 week post-phacoemulsification
12.4 G 3.3
10.6 G 3.2
11.3 G 4.4
.76
1 month post-phacoemulsification
14.6 G 4.2
10.9 G 3.8
11.8 G 3.3
.14
3 months post-phacoemulsification
13.1 G 2.5 (n Z 10)
12.0 G 3.1 (n Z 14)
11.2 G 4.4 (n Z 13)
.48
*Kruskal-Wallis test.
compared with the control group. Although the followup period was only 1 month, these authors reported in another study11 total disappearance of the dye within 1 week after ICG-assisted surgeries. Concerning the use of trypan blue 0.1% for staining the anterior capsule, Melles and coauthors2 found no evidence of impaired corneal endothelial function over a 12-month follow-up, but the safety of trypan blue has not been objectively demonstrated by documenting endothelial cell counts. In a study by Jacob et al.,3 the changes in endothelial cell counts were only available in some patients and there was no control group for comparison. The phaco energies were similar in the 3 studied groups. This is expected because the capsule stain simply facilitates anterior capsulorhexis by enhancing its visualization and should have no effect on phacoemulsification. Because the sample size was relatively small and the phaco time was similar in the 3 groups, we were unable to demonstrate a correlation between the phaco energy and the endothelial cell loss. Furthermore, because there was no significant difference in the phaco time between the 3 groups and no correlation between the phaco energy and the mean postoperative endothelial cell loss, any significant difference in the postoperative endothelial cell loss in the trypan and ICG groups is more likely related to the capsule stains. Our results show relatively high endothelial cell loss in all 3 groups. This may be due to the density of the mature cataract. There was no significant difference between the endothelial cell loss in the 3 groups up to 3 months after surgery. Therefore, trypan blue and ICG should have minimal toxicity on corneal endothelial cells. Unfortunately, it was difficult to quantify and compare the level of difficulty encountered by the surgeon during CCC with and without the use of stain. There were 2 patients in the control group with posterior capsule tear and vitreous loss, but none in the other 2 groups had a similar complication. We were, however,
unable to show a statistically significant difference between the use of capsule stain and the control with reference to the rate of this intraoperative complication. The complications could have occurred whether capsule stain was used or not because the 2 cases had successful CCC performed and the posterior capsule tear occurred during phacoemulsification of the nucleus. In conclusion, compared with our control group, both trypan 1% and ICG 0.5% were found to be safe with reference to change in endothelial cell count and corneal clarity. Neither stain was associated with postoperative IOP elevation or persistent anterior chamber inflammation.
References 1. Horiguchi M, Miyake K, Ohta I, Ito Y. Staining of the lens capsule for circular continuous capsulorrhexis in eyes with white cataract. Arch Ophthalmol 1998; 116: 535–537 2. Melles GRJ, de Waard PWT, Pameyer JH, Beekhuis WH. Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery. J Cataract Refract Surg 1999; 25:7–9 3. Jacob S, Agarwal A, Agarwal A, et al. Trypan blue as an adjunct for safe phacoemulsification in eyes with white cataract. J Cataract Refract Surg 2002; 28:1819–1825 4. Dada VK, Sharma N, Sudan R, et al. Anterior capsule staining for capsulorhexis in cases of white cataract; comparative clinical study. J Cataract Refract Surg 2004; 30:326–333 5. Kogure K, David NJ, Yamanouchi U, Choromokos E. Infrared absorption angiography of the fundus circulation. Arch Ophthalmol 1970; 83:209–214 6. Burk SE, Da Mata AP, Snyder ME, et al. Indocyanine green-assisted peeling of the retinal internal limiting membrane. Ophthalmology 2000; 107:2010–2014 7. McEnerney JK, Peyman GA. Indocyanine green: a new vital stain for use before penetrating keratoplasty. Arch Ophthalmol 1978; 96:1445–1447 8. Gain P, Thuret G, Chiquet C, et al. Value of two mortality assessment techniques for organ cultured corneal endothelium: trypan blue versus TUNEL technique. Br J Ophthalmol 2002; 86:306–310
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
9. Holley GP, Alam A, Kiri A, Edelhauser HF. Effect of indocyanine green intraocular stain on human and rabbit corneal endothelial structure and viability; an in vitro study. J Cataract Refract Surg 2002; 28:1027– 1033 10. Engelbrecht NE, Freeman J, Sternberg P Jr, et al. Retinal pigment epithelial changes after macular hole sur-
942
gery with indocyanine green-assisted internal limiting membrane peeling. Am J Ophthalmol 2002; 133:89– 94 11. Horiguchi M, Nagata S, Yamamoto N, et al. Kinetics of indocyanine green dye after intraocular surgeries using indocyanine green staining. Arch Ophthalmol 2003; 121:327–331
J CATARACT REFRACT SURG—VOL 31, MAY 2005
P
hacoemulsification has several advantages over extracapsular cataract extraction (ECCE), including a smaller wound with less induced astigmatism and a shorter visual rehabilitation period. In mature cataract,
Accepted for publication September 14, 2004. From the Department of Ophthalmology (Chung, Liang, Lai), United Christian Hospital, Department of Ophthalmology (Lo), Tseung Kwan O Hospital, and Department of Ophthalmology and Visual Sciences (Lam), The Chinese University of Hong, Hong Kong SAR, China. No author has a financial or proprietary interest in any material or method mentioned. Reprint requests to Dr. Jimmy S.M. Lai, Department of Ophthalmology, United Christian Hospital, Hip Wo Street, Kwun Tong, Kowloon, Hong Kong SAR, China. E-mail: [email protected]. 2005 ASCRS and ESCRS Published by Elsevier Inc.
however, defined as totally opacified lens matter in the presence of normal anterior chamber depth precluding visualization of the red reflex, continuous curvilinear capsulorhexis (CCC) may be difficult. A poorly performed anterior capsulorhexis increases surgical risk in the later part of surgery. Trypan blue and indocyanine green (ICG) have been used as adjuncts for enhancing the visibility of the anterior capsule in cataract surgery.1–4 In vitro study of trypan blue toxicity on ocular tissues is not available. Indocyanine green (ICG) is a nontoxic tricarbocyanine and has been used for studying the choroidal circulation since 1970.5 Recently, ICG began to be used for peeling the internal limiting membrane during macular surgery.6 Both ICG and trypan blue selectively stain 0886-3350/05/$-see front matter doi:10.1016/j.jcrs.2004.12.046
VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
devitalized corneal endothelial cells.7,8 Indocyanine green was found to be nontoxic to rabbit endothelial cell function in perfusion studies.9 Exposure to ICG 0.5% of up to 3 minutes caused no adverse effect to the corneal endothelial function, ultrastructure, and viability in either human and rabbit corneas in vitro.9 The effects of ICG or trypan blue on intraocular structures in vivo have not been fully studied. The aim of this study was to assess the safety of trypan blue and ICG used as adjuncts for performing CCC in eyes with mature cataract having phacoemulsification.
a foldable acrylic intraocular lens (AcrySof MA30BA, Alcon) was implanted. The viscoelastic agent was completely aspirated. All the operations were performed by 1 of 2 surgeons (J.S.L., B.C.L.). The absolute phaco time in seconds was recorded. Chloramphenicol 0.5% and dexamethasone 0.1% (Neo-Dex) eyedrops were given to all patients for a period of 6 weeks. Follow-up was 1 day, 1 week, 1 month, and 3 months after surgery. Visual acuity, AC reaction, corneal clarity, and IOP were recorded. The endothelial cell count was measured at 1 week, 1 month, and 3 months. Nonparametric tests were used for statistical analysis. The Kruskal-Wallis test was used for analyzing differences among the 3 groups. Spearman’s rho was used for calculating the level of correlation between 2 variables.
Patients and Methods This prospective randomized clinical trial included 46 eyes of 46 consecutive patients with mature cataract who had phacoemulsification and posterior chamber intraocular lens implantation between June 2002 and March 2003. Exclusion criteria included preexisting corneal diseases such as cornea guttata or scar, history of uveitis, glaucoma, and intraoperative complications of posterior capsular tear and vitreous loss. The study was approved by the Research Ethics Committee of the United Christian Hospital, Hong Kong. Preoperative assessment included visual acuity, endothelial cell count (measured by an assigned optometrist with the Konan Specular Microscopy Noncon Robo SP 6000) and intraocular pressure (IOP) measurements. After providing informed consent, patients were randomly assigned (SD) using a randomization table into 1 of the 3 groups: (1) trypan blue 1% (undiluted Vision Blue solution), (2) ICG 0.5% (25 mg Diagnogreen in 5 mL Aqsia solution), and (3) control group without capsular stain. One hour before surgery, the pupils were dilated with tropicamide 0.5% and phenylephrine 0.5% (Mydrin-P) applied 3 times at 10-minute intervals. Either topical or regional anesthesia was used. The trypan blue was a premixed commercial preparation. The ICG was prepared by dissolving 25 mg of the powder in 5 mL of sterile water; 1 mL of the dissolved ICG was aspirated and mixed with 9 mL of sterile Aqsia solution (Chauvin Opsia). A superior 3.2 mm clear corneal wound was constructed. Air was injected into the anterior chamber (AC) through a paracentesis wound to displace the aqueous; 0.5 ml of either trypan blue or ICG was then injected and left in the AC for 2 minutes. The stain was removed with Aqsia solution. In the control group, no capsule stain was used. Sodium chondroitin sulfate–sodium hyaluronate (Viscoat) was then injected into the AC, and anterior CCC was performed using a Utrata forceps followed by hydrodissection. Stop-and-chop phacoemulsification was performed using the Millennium CX 6000 (Bausch & Lomb Surgical). After the nucleus and cortex were removed, sodium hyaluronate (Provisc) was injected in the capsular bag, and
Results The study included 49 patients. In all 3 groups, anterior CCC was completed without tear. One patient in the trypan blue group required conversion to ECCE, and 2 patients in the control group had PC tear with vitreous loss. These 3 patients were excluded, leaving 46 patients for data analysis. Mean age was 66.4 years G 10.0 years (10 women, 4 men) in the trypan blue group, 73.1 G 8.8 years in the ICG group (7 women, 10 men), and 71.5 G 9.6 years in the control group (8 women, 7 men) (P Z .15). Seven patients (2 in the trypan blue, 3 in the ICG, and 2 in the control groups) defaulted the 3-month follow-up. The percentage of patients with preoperative visual acuity of counting fingers or less was 100%, 82.4%, and 80.0% in the trypan blue, ICG, and control groups, respectively. Three months postoperatively, 78.6%, 41.2%, and 46.7% of patients in the respective groups had a best corrected visual acuity of R.5. Table 1 summarizes the characteristics of the patients in the 3 groups. There was no significant difference in the absolute phaco time between the 3 groups: 18.0 G 5.1 seconds, 22.3 G 7.8 (SD) seconds, and 22.3 G 8.4 seconds, respectively (P Z .17). There was no significant difference in the mean endothelial cell loss (difference between the preoperative and the postoperative endothelial cell counts) in the 3 groups (trypan blue, ICG, and control groups, respectively: 510 G 634 cells/mm2, 510 G 927 cells/mm2, and 707 G 685 cells/mm2 at 1 week postoperative, P Z .72; 657 G 558 cells/mm2, 592 G 678 cells/mm2, and 950 G 682 cells/mm2 at
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
Table 1.
Characteristics in the 3 groups.
Characteristic
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value*
Mean age (years)
66.4 G 10.0
73.1 G 8.8
71.5 G 9.6
.15
Sex
10 Female:4 Male
7 Female:10 Male
8 Female:7 Male
—
Patients (%) with visual acuity % counting finger
100.0
82.4
80.0
—
Preoperative IOP (mm Hg)
12.8 G 2.6
12.1 G 2.7
13.3 G 4.0
.76
Mean phaco time (seconds)
18.0 G 5.1
22.3 G 7.8
22.3 G 8.4
.17
Means GSD *Kruskal-Wallis test.
1 month postoperative, P Z .43; and 526 G 404 cells/ mm2, 718 G 655 cells/mm2, and 658 G 614 cells/mm2 at 3 months postoperative, P Z .60; Table 2). No correlation between phaco energy and mean endothelial cell loss at 1 week (correlation coefficient 0.11, P Z .50), 1 month (correlation coefficient 0.25, P Z .10), or 3 months (correlation coefficient 0.13, P Z .46) after phacoemulsification was found in any group. The mean postoperative IOPs for the 3 groups are shown in Table 3. There was no significant difference in mean IOP between the 3 groups at various times of follow-up. No patient had IOP greater than 21 mm Hg at any of the scheduled postoperative visits, and none required IOP-lowering medication. None of the patients had excessive postoperative AC reaction in the form of fibrinous exudation, and none required prolonged use of topical steroid for control of AC inflammation. Table 2.
Two patients in the ICG group had mild corneal haziness 1 month after the operation, but clarity returned at 3 months.
Discussion A properly performed anterior CCC is an important step in the success of phacoemulsification. The red reflex in eyes with a white mature cataract is poor, and visualization of the anterior capsule is difficult. Trypan blue and ICG had been used for staining the anterior capsule for CCC and were found to be safe.1–4 A high incidence of retinal pigment epithelial changes within the macula after ICG-assisted macula hole surgery has been reported.10 In a study by Horiguchi and coauthors,1 ICG 0.5% was used to stain the anterior capsule for CCC in phacoemulsification in white cataract. They found no significant difference in the endothelial cell count of eyes that had been stained
Mean endothelial cell count and postoperative endothelial cell loss in the 3 groups.
Examination
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value, Mean
Pre-phacoemulsification Mean endothelial cell count (mmÿ2)
2525 G 319
2213 G 393
2574 G 466
—
1995 G 639
1726 G 858
1870 G 702
.72
1 week post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
510 G 634 (20.2)
510 G 927 (23.0)
707 G 685 (27.5)
1 month post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
1868 G 627 657 G 558 (26.0)
1621 G 615 592 G 678 (26.7)
1629 G 671
.43
950 G 682 (36.9)
3 months post-phacoemulsification Mean endothelial cell count (mmÿ2) Mean endothelial cell loss (%)
940
2055 G 344
1535 G 651
1897 G 726
526 G 404 (20.8)
718 G 655 (32.4)
658 G 615 (25.6)
(n Z 10)
(n Z 14)
(n Z 13)
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
Table 3.
Postoperative mean IOP (mm Hg) in the 3 groups.
Examination
Trypan Blue (n [ 14)
ICG (n [ 17)
Control (n [ 15)
P Value*
1 week post-phacoemulsification
12.4 G 3.3
10.6 G 3.2
11.3 G 4.4
.76
1 month post-phacoemulsification
14.6 G 4.2
10.9 G 3.8
11.8 G 3.3
.14
3 months post-phacoemulsification
13.1 G 2.5 (n Z 10)
12.0 G 3.1 (n Z 14)
11.2 G 4.4 (n Z 13)
.48
*Kruskal-Wallis test.
compared with the control group. Although the followup period was only 1 month, these authors reported in another study11 total disappearance of the dye within 1 week after ICG-assisted surgeries. Concerning the use of trypan blue 0.1% for staining the anterior capsule, Melles and coauthors2 found no evidence of impaired corneal endothelial function over a 12-month follow-up, but the safety of trypan blue has not been objectively demonstrated by documenting endothelial cell counts. In a study by Jacob et al.,3 the changes in endothelial cell counts were only available in some patients and there was no control group for comparison. The phaco energies were similar in the 3 studied groups. This is expected because the capsule stain simply facilitates anterior capsulorhexis by enhancing its visualization and should have no effect on phacoemulsification. Because the sample size was relatively small and the phaco time was similar in the 3 groups, we were unable to demonstrate a correlation between the phaco energy and the endothelial cell loss. Furthermore, because there was no significant difference in the phaco time between the 3 groups and no correlation between the phaco energy and the mean postoperative endothelial cell loss, any significant difference in the postoperative endothelial cell loss in the trypan and ICG groups is more likely related to the capsule stains. Our results show relatively high endothelial cell loss in all 3 groups. This may be due to the density of the mature cataract. There was no significant difference between the endothelial cell loss in the 3 groups up to 3 months after surgery. Therefore, trypan blue and ICG should have minimal toxicity on corneal endothelial cells. Unfortunately, it was difficult to quantify and compare the level of difficulty encountered by the surgeon during CCC with and without the use of stain. There were 2 patients in the control group with posterior capsule tear and vitreous loss, but none in the other 2 groups had a similar complication. We were, however,
unable to show a statistically significant difference between the use of capsule stain and the control with reference to the rate of this intraoperative complication. The complications could have occurred whether capsule stain was used or not because the 2 cases had successful CCC performed and the posterior capsule tear occurred during phacoemulsification of the nucleus. In conclusion, compared with our control group, both trypan 1% and ICG 0.5% were found to be safe with reference to change in endothelial cell count and corneal clarity. Neither stain was associated with postoperative IOP elevation or persistent anterior chamber inflammation.
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VISUALIZATION OF ANTERIOR CAPSULE DURING PHACOEMULSIFICATION
9. Holley GP, Alam A, Kiri A, Edelhauser HF. Effect of indocyanine green intraocular stain on human and rabbit corneal endothelial structure and viability; an in vitro study. J Cataract Refract Surg 2002; 28:1027– 1033 10. Engelbrecht NE, Freeman J, Sternberg P Jr, et al. Retinal pigment epithelial changes after macular hole sur-
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