Seminars in Ophthalmology, 2015; 30(2): 96–100 ! Informa Healthcare USA, Inc. ISSN: 0882-0538 print / 1744-5205 online DOI: 10.3109/08820538.2013.833261
ORIGINAL ARTICLE
A Clinical Comparison of Safety and Efficacy in Phacoemulsification with versus without Ophthalmic Viscoelastic Device Suleyman Kugu1, Gurkan Erdogan2, M. Sahin Sevim3, and Yusuf Ozerturk1
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1
Dr. Lutfi Kırdar Kartal Training and Research Hospital, Eye Clinic, Istanbul, Turkey, 2Umraniye Training and Research Hospital, Eye Clinic, Istanbul, Turkey, and 3Haydarpasa Numune Training and Research Hospital Eye Clinic, Istanbul, Turkey
ABSTRACT Purpose: To evaluate in a comparative manner the safety and efficacy of 1.0% sodium-Hyaluronate used during capsulorhexis and intraocular lens (IOL) implantation in phacoemulsification surgery. Materials and Methods: 1.0% sodium-Hyaluronate, which is commonly used as one of the ophthalmic viscoelastic devices, was compared to intraocular irrigating solution, which can bring up these effects. In addition, the effect of both methods on occurring corneal endothelial cell (CEC) loss was investigated. Results: Each group comprised 19 eyes. The mean preoperative CEC density was 2525.68 181.85 in Group H and 2514.16 174.59 in Group V; no statistically significant difference was found between the groups (p40.05). Preoperative and postoperative first and twelfth week CEC densities were 2438.21 198.12 (p50.001) and 2390.74 202.31, respectively, in group H (p50.001). Preoperative and postoperative first and twelfth week CEC densities were 2415.32 197.24 (p50.001) and 2353.47 212.69 in group V (p50.001). Compared with preoperative values, decrease in CEC density on the postoperative first and twelfth weeks was not statistically significant in either group (p40.05). Conclusion: Although it was found that there was no statistically difference in terms of preventing CEC loss between 1.0% sodium-Hyaluronate and the irrigation method during phacoemulsification, it was observed clinically that 1.0% sodium-hyaluronate can make the procedure easy, safer, very helpful, especially for understanding phacoemulsification. Keywords: Corneal endothelial cell, intraocular irrigating solution, ophthalmic viscoelastic device, phacoemulsification, sodium-Hyaluronate
INTRODUCTION
the movement of fluid as well as an active pump across the cornea. The corneal endothelial cells are non-dividing cells developing a pumping activity that is crucial for corneal clarity and integrity. There is a slowly and gradually physiological corneal endothelial cell loss with age from about 4000 cells/mm2 at birth to about 1400 to 2500 cells/mm2 in adults8; it is well-known that this rate is significantly higher after intraocular surgical procedures such as phacoemulsification. During phacoemulsification, ophthalmic viscosurgical devices (OVDs) are needed to create and maintain space in the anterior chamber while performing capsulorhexis and in the capsule and anterior
Currently, phacoemulsification (PHACO) is the gold standard and most frequently used method for the treatment of cataracts. Extremely satisfactory results are being obtained owing to advances in surgical techniques and advanced technology products. However, despite all these facilities, corneal endothelial cell loss occurs due to various factors, with a loss rate between 6.9% and 42.6% reported in various studies.1–7 Corneal transparency is maintained by the corneal endothelial cells, which serve as a physical barrier to
Received 9 March 2013; accepted 6 August 2013; published online 19 September 2013 Correspondence: Gurkan Erdogan, [email protected]
MD,
Umraniye
Training
and
96
Research
Hospital,
Eye
Clinic,
Istanbul,
Turkey.
E-mail:
Semin Ophthalmol Downloaded from informahealthcare.com by Kainan University on 04/07/15 For personal use only.
Comparison of Phacoemulsification with versus without Viscoelastic chamber during intraocular lens (IOL) implantation; irrigation fluid is used for this purpose at other stages. It is known that OVDs have a protective effect on corneal endothelial cells.3,9 If the number of cells decreases to below a certain density, corneal oedema appears. The critical density is estimated to be 600-800 cells/mm2. Loss of endothelial cells is compensated by cellular enlargement, cell gliding, rearrangement, and cell coalescence8. An important descriptor of the endothelial cell population is the coefficient of variation of the mean cell area, which is useful in following cellular reorganization after cataract surgery. The aim of the present study was to evaluate the protective effect of 1.0% sodium-Hyaluronate (PROVISCÕ , Alcon), used during capsulorhexis and IOL implantation in phacoemulsification surgery, on corneal endothelial cells.
MATERIALS AND METHODS The present study comprised 38 eyes of 21 consecutive patients diagnosed with senile cataracts between August 2011 and November 2011 in the ophthalmology clinic of the Turkish Ministry of Health Dr. Lu¨tfi Kırdar Kartal Training and Research Hospital. The study protocol was approved by The Medical Ethics Committee of the Ophthalmic Research Center of the hospital. The patients were informed about the study and detailed informed consents were obtained as signed. Inclusion criteria included being diagnosed with senile cataract, no history for previous intraocular surgery or ocular trauma, not having pseudoexfoliation, having no intraocular inflammation in the past, not having diabetes mellitus, being male or female over the age of 50 years but not exceeding 75 years, and not having glaucoma or ocular hypertension. Eyes that developed complications during surgery, small eyes with a pupil diameter of approximately 5 mm, eyes with a preoperative ED of 2000 cells/mm2, brown and very hard cataracts, corneal scars, corneal endothelial dystrophy, and eyes with an axial length higher than 25 mm or lower than 20 mm were not included in the study. Preoperative uncorrected and best corrected visual acuity measurements, biomicroscopic examination, and intraocular pressure measurement by Goldmann applanation tonometry (Haag-Streit International) and fundoscopy were performed in all patients through a pupil dilated with tropicamide and phenylephrine. Nucleus density was evaluated using the Lens Opacities Classification System III.10 Biometric measurement was done by IOL Master (Haag-Streit International) and keratometric values; axial length and IOL power were calculated. Corneal endothelial cell count was done by a single physician using a !
2015 Informa Healthcare USA, Inc.
97
noncontact specular microscope (SP-2000 P, Topcon, Japan) by means of checking at least 50 cells on the picture taken from the central cornea. The patients were randomized into two groups. Phacoemulsification was performed using OVDs in Group V and without OVDs in Group H. Phacoemulsification was performed by the same device (Infiniti, Alcon, Inc.) and 30-degree tip (bevel Kelman configuration) in both Group V and Group H. All stages were performed by a single physician using a linear power of 50%, a constant flow rate of 36 cc/min, and a linear vacuum of 500 mm Hg. Topical anesthesia was performed with eyedrops, and a sterile drape was placed after cleaning the eye contour with povidone iodine. Conjunctiva, cornea, and free margin of the lower lid were washed with povidone iodine, which has been ½ diluted with 0.9% normal saline, for two minutes. After the lateral port was opened by 20-gauge MVR (microvitreoretinal), the anterior chamber was irrigated with 2% Lidocaine HCl (Aritmal amp., Osel, Turkey). Surgical procedure was performed by approximately 80–90 cm increasing the irrigation solution (BSS PLUSÕ , Alcon). Capsulorhexis was performed in Group V by filling the anterior chamber with 1.0% Na-Hyaluronate (PROVISCÕ , Alcon) and obtaining 0.5 mm cystotome through the corneal incision, done by a 2.8 mm slit knife (slit angled 2.8 mm, MANI, Japan), by 120 degree twirling of the 0.5 mm tip of 27-gauge insulin injector. In Group H, irrigation solution was given to the posterior aspect of the cystotome, which was obtained by 120 degree twirling of the 0.5 mm tip of 27-gauge insulin injector through a side port that was not completely inserted into the anterior chamber but marked; irrigation was completed in the anterior chamber depth, providing fluid by elevating irrigation bottle when needed. After completing capsulorhexis in Group H, a clear corneal incision was performed. A quick-chop technique was used for nucleus emulsification following hydrodissection. Bimanual aspiration/irrigation was done using the parameters of a constant flow rate of 36 cc/min and a linear vacuum of 500 mm Hg. The anterior chamber and the capsule were filled with PROVISCÕ in Group V, whereas acrylic hydrophobic-coated IOL (Acriva BB UD 613 Monofocal, VSY Biotechnology), which was previously placed into the cartridge under irrigation fluid, was implanted via an injector in Group H. Only BSS PLUSÕ (Alcon) was used in Group H while IOL was being placed into the cartridge. In Group V, PROVISCÕ bimanual aspiration/irrigation was done from the anterior chamber by a constant flow rate of 36 cc/min and a linear vacuum of 500 mm Hg. Margins of the corneal incision were bloated with fluid and the anterior chamber was irrigated with antibiotics (cefuroxime, 1 ml/0.1 ml). Phacoemulsification time and amount of the fluid used during surgical procedure were recorded after
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98 S. Kugu et al. each phacoemulsification surgery. Postoperative 1% prednisolone acetate suspension (Pred Forte, Allergan) and 0.3% gatifloxacin (ZymarÕ, Allergan) eyedrops were prescribed in the form of a single drop every two hours and gradually decreased over 15 days. Differences between groups in demographic and clinical characteristics were evaluated using Fisher exact test and Student’s t test. Preoperative and postoperative corneal endothelial cell density changes within the groups were analyzed using Student’s t test, repeated measures, and bonferroni. The mean difference between the periods was analyzed by a Mann Whitney U test in both groups and the amount of irrigation fluid used in the course of surgery, as well as the mean phacoemulsification times, were analyzed by Student’s t test. A p value smaller than 50.05 was considered statistically significant.
RESULTS In total, 38 eyes of 21 patients, of whom 12 were male and nine were female, were included in the study. There was no difference between the groups in terms of gender (p40.05) (Table 1). The groups were matched in terms of mean age, which was found to be 60.22 4.76 years in Group H and 61.90 5.37 years in Group V (p = 0.472) (Fisher’s exact test) (Table 2). Preoperative CEC density was 2525.68 181.85 in Group H and 2514.16 174.59 and Group V; the difference was not statistically significant (p40.05). The groups showed no statistically significant difference in terms of mean CEC values on the postoperative first and twelfth weeks as well as on the preoperative period (p40.05) (Student’s t test). Postoperative first and twelfth week values were significantly lower than preoperative values both in Group H and in Group V (p50.001) (repeated measures and bonferroni). Postoperative twelfth week TABLE 1. Gender Distribution among groups. Group H
Male Female
Group V
n
%
n
%
p
7 3
70.0 30.0
5 6
45.5 54.5
0.387
Fisher’s exact test.
Group H
The objective of this study was to evaluate the effect of 1.0% sodium-Hyaluronate (PROVISCÕ , Alcon) on CEC loss and its efficacy. CEC loss is more likely in eyes with a short axial length, old age, dense cataract, small pupil, preoperative inflammation, past ocular trauma, and intraocular surgery.11,12 CEC loss during cataract surgery can also occur as a result of several intraoperative factors, including toxic intraoperative medications, surgical corneal incisions, Descemet’s membrane detachment, fluid turbulence inside the anterior chamber, total amount of ultrasound energy used, ultrasound energy dissipated close to the CEC, phacoemulsification parameters, free radicals, surgical complications such as posterior capsule rupture and vitreous loss that prolong surgery duration and manipulation, direct contact of surgical device on CEC and hard nucleus, anterior chamber collapse that leads to corneal deformity, IOL-related problems, inadequate surgical experience, and postoperative inflammation.1,2,4,6,7,11,13–16 In the present study, CEC loss in either group was assessed via cell density calculation on a specular microscope. Cell morphology secondary to CEC loss and central corneal thickness, which is not usually parallel, were not taken into consideration.17 Statistically significant CEC loss was detected on the postoperative first and twelfth week as compared to TABLE 3. Preoperative and postoperative corneal endothelial cell density.
Mean Group V
Mean
SD
Mean
SD
p
60.22
4.76
61.90
5.37
0.472
Student’s t test.
DISCUSSION
Group H
TABLE 2. Mean age of the groups.
Age
values were significantly lower than the postoperative first week values both in Group H and in Group V (p50.001) (repeated measures and bonferroni) (Table 3). The mean corneal endothelial count during preoperative period and on the postoperative first and twelfth week is shown as a graph in Figure 1. There was no statistically significant difference between the groups in terms of mean values of differences between the periods (p40.05) (Mann Whitney U test) (Table 4). The amount of irrigation fluid used in the course of phacoemulsification surgery and phacoemulsification time was found statistically similar in both groups (p40.05) (Student’s t test) (Table 5).
Group V
SD
Mean
SD
p*
Preoperative 2525.68 181.85 2514.16 174.59 0.843 Postoperative 1st week 2438.21 198.12 2415.32 197.24 0.723 Postoperative 12th week 2390.74 202.31 2353.47 212.69 0.583 0.001 0.001 pa *Student’s t test. a repeated measures and bonferroni. Seminars in Ophthalmology
Comparison of Phacoemulsification with versus without Viscoelastic
99
2550 2500 2450 Group H
2400
Group V
2350 2300 2250 PREOP
POSTOP 1st week
POSTOP 12th week
FIGURE 1. Preoperative and postoperative corneal endothelial cell density.
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TABLE 4. The mean of the difference between the periods in the groups. Group H
Group V
Absolute change
Mean
SD
Mean
SD
p
Preoperative and postoperative 1st week Preoperative and postoperative 12th week Postoperative 1st and 12th week
87.47 134.95 47.47
73.00 74.79 42.81
98.84 160.68 61.84
51.07 60.01 47.35
0.751 0.138 0.418
Mann Whitney U test. TABLE 5. Time of surgery and mean amount of irrigation fluid used in each group. Group H
Mean irrigation solution used (ml) Phacoemulsification time
Group V
Mean
SD
Mean
SD
p
76.54
28.25
73.84
25.56
684
1.25
0.82
735
1.21
062
Student’s t test.
the preoperative values in both groups, in which the surgical procedure was performed without complication. However, the rate of CEC loss was not statistically significant in either group. No doubt, OVDs provide considerable advantages and facilities in cataract surgery. OVDs are essential devices in cataract surgery owing to their ability to preserve and maintain anatomic spaces, enabling the use of surgical equipment and, sometimes, providing a better view. There are numerous studies reporting that OVDs decrease CEC loss.3,9 However, the number of studies comparing their superiority over each other is limited.18 Preserving and maintaining the anterior chamber during cataract surgery is mandatory, particularly for the protection of CEC. The mini-nuc method developed by Blumenthal19,20 provides this by anterior chamber maintainer (ACM) under irrigation fluid. IOL implantation to the posterior chamber has been possible with ACM through the scleral tunnel. Whereas irrigation and capsulorhexis can be done via cystotome during phacoemulsification, IOL implantation via a cartridge-injector !
2015 Informa Healthcare USA, Inc.
system under irrigation enabled us to conduct the present study. The mean difference between the two groups in terms of phacoemulsification time, phacoemulsification power, and amount of irrigation fluid used was not statistically significant. Irrigation fluid used in both groups was BSS PLUSÕ (Alcon), which is currently considered to be the most suitable one due to its contents.21 Capsulorhexis under fluid is different from the use of OVDs and requires a training period. Access site to the anterior chamber via a cystotome, to which the irrigation fluid is attached, should be so narrow that it can prevent leakage; otherwise, fluctuation of the anterior chamber might cause capsulorhexis to move to the periphery. During capsulorhexis under fluid, the anterior capsule is motile due to turbulence of the fluid, but it would not pose a problem with appropriate maneuvers. Intraocular pressure increment can be seen in the early postoperative period following phacoemulsification due to poorly aspirated OVDs from the anterior chamber; however, we did not observe such a complication in our cases, probably because 1.0% Na-Hyaluronate (PROVISCÕ , Alcon) has been easily removed from the anterior chamber by irrigation/aspiration. IOL was implanted by a cartridge-injector system under fluid in Group H and neither scratch nor another deformation was observed on the IOL surface when examined under a surgical microscope and postoperative biomicroscope after in-the-bag implantation. In the event of such a situation, OVDs would be used while placing IOL into the cartridge-injector system.
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100 S. Kugu et al. The absence of statistically significant difference in terms of CEC loss after phacoemulsification performed with and without OVDs can be assessed in various ways. First, phacoemulsification time was equal in both groups and was relatively short. The endothelial-cell-protecting effect of OVDs might be more remarkable in the case of longer phacoemulsification time. Second, the amount of irrigation fluid used during surgery was low. A higher amount of irrigation fluid will cause CEC to come across with more fluid turbulence, probably leading to increased loss rate. Third, the effect of OVDs might be better in the cases with a CEC number under a certain critical value. The above-mentioned reasons are also the limitations of the present study. There is a need for CEC to be investigated under distinct conditions and situations during cataract surgery. The result does not indicate that the use of OVDs during phacoemulsification has no direct protective effect on CEC, but indicates that many other factors that cause CEC loss during phacoemulsification might be more important. It is beyond dispute that 1.0% sodium-Hyaluronate used during phacoemulsification facilitates the procedure, makes it safer, and provides substantial benefits during the training period. It is known that the use of OVDs during PHACO has a protective effect on CEC. However, which mechanisms play a role in this protective effect is not clearly known and it is assumed that the effect occurs via forming and maintaining the anatomic space. In the present study, we failed to determine the significant protective effect of 1.0% sodiumHyaluronate over BSS PLUSÕ (Alcon) on CEC cell loss during phacoemulsification. However, further studies are needed to investigate the factors and conditions that lead to corneal endothelial cell loss during phacoemulsification.
DECLARATION OF INTEREST The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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5.
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REFERENCES 19. 1. Reuschel A, Bogatch H, Barth T, Wiedemann R. Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification. J Cataract Refract Surg 2010;36:1855–1861. 2. Baradaran-Rafii A, Rahmati-Kamel M, Eslani M, et al. Effect of hydrodynamic parameters on corneal endothelial cell loss after phacoemulsification. J Cataract Refract Surg 2009;35:732–737. 3. Storr-Paulsen A, Norregaard JC, Farik G, Tarnhoj J. The influence of viscoelastic substances on the corneal
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endothelial cell population during cataract surgery: A prospective study of cohesive and dispersive viscoelastics. Acta Ophthalmol Scand 2007;85:183–187. Milla E, Verges C, Cipres M. Corneal endothelium evaluation after phacoemulsification with continuous anterior chamber infusion. Cornea 2005;24:278–282. Wirbelauer C, Anders N, Pham DT, Wollensak J. Corneal endothelial cell changes in pseudoexfoliation syndrome after cataract surgery. Arch Ophthalmol 1998;119:145–149. Nemet AY, Assia EI, Meyerstein D, et al. Protective effect of free-radical scavengers on corneal endothelial damage in phacoemulsification. J Cataract Refract Surg 2007;33: 310–315. Kim EC, Byun YS, Kim MS. Microincision versus smallincision coaxial cataract surgery using different power modes for hard nuclear cataract. J Cataract Refract Surg 2011;37:1799–1805. Gipson IK, Joyce NC. Anatomy and cell biology of the cornea, superficial limbus and conjunctiva. In: Principles and Practice of Ophthalmology, 2nd ed. (Albert DM, Jacobiec FA, Eds.); pp. 612–628; Philadelphia: Saunders, 2000. Miyata K, Maruoka S, Nakahara M, et al. Corneal endothelial cell protection during phacoemulsification: Low-versus high-molecular-weight sodium hyaluronate. J Cataract Refract Surg 2002;28:1557–1560. Chylack LK, Wolfe JK, Singer DM, et al. The lens Opacities Classification System III: the Longutidinal Study of Cataract Study Group. Arch Ophthalmol 1993;111:831–836. Walkow T, Anders N, Klebe S. Endothelial cell loss after phacoemulsification: Relation to preoperative and intraoperative parameters. J Cataract Refract Surg 2000;26: 727–732. Storr-Paulsen A, Norregaard JC, Farik G, et al. Endothelial cell damage after cataract surgery: Divide-and-conquer versus phaco-chop technique. J Cataract Refract Surg 2008;34:996–1000. Bourne RRA, Minassian DC, Dart JKG, et al. Effect of cataract surgery on the corneal endothelium: Modern phacoemulsification compared with extracapsular cataract surgery. Ophthalmology 2004;111:679–685. Bourne WM, Kaufman HE. Endothelial damage associated with intraocular lenses after cataract surgery. Am J Ophthalmol 1976;81:482–485. Craig MT, Olson RJ, Mamalis N, Olson MT. Air bubble endothelial damage during phacoemulsification in human eye bank eyes: The protective effects of Healon and Viscoat. J Cataract Refract Surg 1990;16:597–602. Hayashi K, Hayashi H, Nakao F, Hayashi F. Risk factor for corneal endothelial injury during phacoemulsification. J Cataract Refract Surg 1996;22:1079–1084. Sobottaka Ventura AC, Walti R, Bo¨hnke M. Corneal thickness and endothelial density before and after cataract surgery. Br J Ophthalmol 2001;85:18–20. Van den Bruel A, Gailly J, Devriese S, et al. The protective effect of ophthalmic viscoelastic devices on endothelial cell loss during cataract surgery: A meta-analysis using mixed treatment comparisons. Br J Ophthalmol 2011;95:5–10. Blumenthal M, Moissiev J. Anterior chamber maintainer for extracapsular cataract extraction and intraocular lens implantation. J Cataract Refract Surg 1987;13:204–206. Blumenthal M, Assia E, Neuman D. Lens anatomic principles and their technical implications in cataract surgery: Part II, The lens nucleus. J Cataract Refract Surg 1991;17:211–217. Glasser DB, Matsuda M, Ellis JG, Edelhauser HF. Effects of intraocular irrigating solutions on the corneal endothelium after in vivo anterior chamber irrigation. Am J Ophthalmol 1985;99:321–328. Seminars in Ophthalmology
ORIGINAL ARTICLE
A Clinical Comparison of Safety and Efficacy in Phacoemulsification with versus without Ophthalmic Viscoelastic Device Suleyman Kugu1, Gurkan Erdogan2, M. Sahin Sevim3, and Yusuf Ozerturk1
Semin Ophthalmol Downloaded from informahealthcare.com by Kainan University on 04/07/15 For personal use only.
1
Dr. Lutfi Kırdar Kartal Training and Research Hospital, Eye Clinic, Istanbul, Turkey, 2Umraniye Training and Research Hospital, Eye Clinic, Istanbul, Turkey, and 3Haydarpasa Numune Training and Research Hospital Eye Clinic, Istanbul, Turkey
ABSTRACT Purpose: To evaluate in a comparative manner the safety and efficacy of 1.0% sodium-Hyaluronate used during capsulorhexis and intraocular lens (IOL) implantation in phacoemulsification surgery. Materials and Methods: 1.0% sodium-Hyaluronate, which is commonly used as one of the ophthalmic viscoelastic devices, was compared to intraocular irrigating solution, which can bring up these effects. In addition, the effect of both methods on occurring corneal endothelial cell (CEC) loss was investigated. Results: Each group comprised 19 eyes. The mean preoperative CEC density was 2525.68 181.85 in Group H and 2514.16 174.59 in Group V; no statistically significant difference was found between the groups (p40.05). Preoperative and postoperative first and twelfth week CEC densities were 2438.21 198.12 (p50.001) and 2390.74 202.31, respectively, in group H (p50.001). Preoperative and postoperative first and twelfth week CEC densities were 2415.32 197.24 (p50.001) and 2353.47 212.69 in group V (p50.001). Compared with preoperative values, decrease in CEC density on the postoperative first and twelfth weeks was not statistically significant in either group (p40.05). Conclusion: Although it was found that there was no statistically difference in terms of preventing CEC loss between 1.0% sodium-Hyaluronate and the irrigation method during phacoemulsification, it was observed clinically that 1.0% sodium-hyaluronate can make the procedure easy, safer, very helpful, especially for understanding phacoemulsification. Keywords: Corneal endothelial cell, intraocular irrigating solution, ophthalmic viscoelastic device, phacoemulsification, sodium-Hyaluronate
INTRODUCTION
the movement of fluid as well as an active pump across the cornea. The corneal endothelial cells are non-dividing cells developing a pumping activity that is crucial for corneal clarity and integrity. There is a slowly and gradually physiological corneal endothelial cell loss with age from about 4000 cells/mm2 at birth to about 1400 to 2500 cells/mm2 in adults8; it is well-known that this rate is significantly higher after intraocular surgical procedures such as phacoemulsification. During phacoemulsification, ophthalmic viscosurgical devices (OVDs) are needed to create and maintain space in the anterior chamber while performing capsulorhexis and in the capsule and anterior
Currently, phacoemulsification (PHACO) is the gold standard and most frequently used method for the treatment of cataracts. Extremely satisfactory results are being obtained owing to advances in surgical techniques and advanced technology products. However, despite all these facilities, corneal endothelial cell loss occurs due to various factors, with a loss rate between 6.9% and 42.6% reported in various studies.1–7 Corneal transparency is maintained by the corneal endothelial cells, which serve as a physical barrier to
Received 9 March 2013; accepted 6 August 2013; published online 19 September 2013 Correspondence: Gurkan Erdogan, [email protected]
MD,
Umraniye
Training
and
96
Research
Hospital,
Eye
Clinic,
Istanbul,
Turkey.
E-mail:
Semin Ophthalmol Downloaded from informahealthcare.com by Kainan University on 04/07/15 For personal use only.
Comparison of Phacoemulsification with versus without Viscoelastic chamber during intraocular lens (IOL) implantation; irrigation fluid is used for this purpose at other stages. It is known that OVDs have a protective effect on corneal endothelial cells.3,9 If the number of cells decreases to below a certain density, corneal oedema appears. The critical density is estimated to be 600-800 cells/mm2. Loss of endothelial cells is compensated by cellular enlargement, cell gliding, rearrangement, and cell coalescence8. An important descriptor of the endothelial cell population is the coefficient of variation of the mean cell area, which is useful in following cellular reorganization after cataract surgery. The aim of the present study was to evaluate the protective effect of 1.0% sodium-Hyaluronate (PROVISCÕ , Alcon), used during capsulorhexis and IOL implantation in phacoemulsification surgery, on corneal endothelial cells.
MATERIALS AND METHODS The present study comprised 38 eyes of 21 consecutive patients diagnosed with senile cataracts between August 2011 and November 2011 in the ophthalmology clinic of the Turkish Ministry of Health Dr. Lu¨tfi Kırdar Kartal Training and Research Hospital. The study protocol was approved by The Medical Ethics Committee of the Ophthalmic Research Center of the hospital. The patients were informed about the study and detailed informed consents were obtained as signed. Inclusion criteria included being diagnosed with senile cataract, no history for previous intraocular surgery or ocular trauma, not having pseudoexfoliation, having no intraocular inflammation in the past, not having diabetes mellitus, being male or female over the age of 50 years but not exceeding 75 years, and not having glaucoma or ocular hypertension. Eyes that developed complications during surgery, small eyes with a pupil diameter of approximately 5 mm, eyes with a preoperative ED of 2000 cells/mm2, brown and very hard cataracts, corneal scars, corneal endothelial dystrophy, and eyes with an axial length higher than 25 mm or lower than 20 mm were not included in the study. Preoperative uncorrected and best corrected visual acuity measurements, biomicroscopic examination, and intraocular pressure measurement by Goldmann applanation tonometry (Haag-Streit International) and fundoscopy were performed in all patients through a pupil dilated with tropicamide and phenylephrine. Nucleus density was evaluated using the Lens Opacities Classification System III.10 Biometric measurement was done by IOL Master (Haag-Streit International) and keratometric values; axial length and IOL power were calculated. Corneal endothelial cell count was done by a single physician using a !
2015 Informa Healthcare USA, Inc.
97
noncontact specular microscope (SP-2000 P, Topcon, Japan) by means of checking at least 50 cells on the picture taken from the central cornea. The patients were randomized into two groups. Phacoemulsification was performed using OVDs in Group V and without OVDs in Group H. Phacoemulsification was performed by the same device (Infiniti, Alcon, Inc.) and 30-degree tip (bevel Kelman configuration) in both Group V and Group H. All stages were performed by a single physician using a linear power of 50%, a constant flow rate of 36 cc/min, and a linear vacuum of 500 mm Hg. Topical anesthesia was performed with eyedrops, and a sterile drape was placed after cleaning the eye contour with povidone iodine. Conjunctiva, cornea, and free margin of the lower lid were washed with povidone iodine, which has been ½ diluted with 0.9% normal saline, for two minutes. After the lateral port was opened by 20-gauge MVR (microvitreoretinal), the anterior chamber was irrigated with 2% Lidocaine HCl (Aritmal amp., Osel, Turkey). Surgical procedure was performed by approximately 80–90 cm increasing the irrigation solution (BSS PLUSÕ , Alcon). Capsulorhexis was performed in Group V by filling the anterior chamber with 1.0% Na-Hyaluronate (PROVISCÕ , Alcon) and obtaining 0.5 mm cystotome through the corneal incision, done by a 2.8 mm slit knife (slit angled 2.8 mm, MANI, Japan), by 120 degree twirling of the 0.5 mm tip of 27-gauge insulin injector. In Group H, irrigation solution was given to the posterior aspect of the cystotome, which was obtained by 120 degree twirling of the 0.5 mm tip of 27-gauge insulin injector through a side port that was not completely inserted into the anterior chamber but marked; irrigation was completed in the anterior chamber depth, providing fluid by elevating irrigation bottle when needed. After completing capsulorhexis in Group H, a clear corneal incision was performed. A quick-chop technique was used for nucleus emulsification following hydrodissection. Bimanual aspiration/irrigation was done using the parameters of a constant flow rate of 36 cc/min and a linear vacuum of 500 mm Hg. The anterior chamber and the capsule were filled with PROVISCÕ in Group V, whereas acrylic hydrophobic-coated IOL (Acriva BB UD 613 Monofocal, VSY Biotechnology), which was previously placed into the cartridge under irrigation fluid, was implanted via an injector in Group H. Only BSS PLUSÕ (Alcon) was used in Group H while IOL was being placed into the cartridge. In Group V, PROVISCÕ bimanual aspiration/irrigation was done from the anterior chamber by a constant flow rate of 36 cc/min and a linear vacuum of 500 mm Hg. Margins of the corneal incision were bloated with fluid and the anterior chamber was irrigated with antibiotics (cefuroxime, 1 ml/0.1 ml). Phacoemulsification time and amount of the fluid used during surgical procedure were recorded after
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98 S. Kugu et al. each phacoemulsification surgery. Postoperative 1% prednisolone acetate suspension (Pred Forte, Allergan) and 0.3% gatifloxacin (ZymarÕ, Allergan) eyedrops were prescribed in the form of a single drop every two hours and gradually decreased over 15 days. Differences between groups in demographic and clinical characteristics were evaluated using Fisher exact test and Student’s t test. Preoperative and postoperative corneal endothelial cell density changes within the groups were analyzed using Student’s t test, repeated measures, and bonferroni. The mean difference between the periods was analyzed by a Mann Whitney U test in both groups and the amount of irrigation fluid used in the course of surgery, as well as the mean phacoemulsification times, were analyzed by Student’s t test. A p value smaller than 50.05 was considered statistically significant.
RESULTS In total, 38 eyes of 21 patients, of whom 12 were male and nine were female, were included in the study. There was no difference between the groups in terms of gender (p40.05) (Table 1). The groups were matched in terms of mean age, which was found to be 60.22 4.76 years in Group H and 61.90 5.37 years in Group V (p = 0.472) (Fisher’s exact test) (Table 2). Preoperative CEC density was 2525.68 181.85 in Group H and 2514.16 174.59 and Group V; the difference was not statistically significant (p40.05). The groups showed no statistically significant difference in terms of mean CEC values on the postoperative first and twelfth weeks as well as on the preoperative period (p40.05) (Student’s t test). Postoperative first and twelfth week values were significantly lower than preoperative values both in Group H and in Group V (p50.001) (repeated measures and bonferroni). Postoperative twelfth week TABLE 1. Gender Distribution among groups. Group H
Male Female
Group V
n
%
n
%
p
7 3
70.0 30.0
5 6
45.5 54.5
0.387
Fisher’s exact test.
Group H
The objective of this study was to evaluate the effect of 1.0% sodium-Hyaluronate (PROVISCÕ , Alcon) on CEC loss and its efficacy. CEC loss is more likely in eyes with a short axial length, old age, dense cataract, small pupil, preoperative inflammation, past ocular trauma, and intraocular surgery.11,12 CEC loss during cataract surgery can also occur as a result of several intraoperative factors, including toxic intraoperative medications, surgical corneal incisions, Descemet’s membrane detachment, fluid turbulence inside the anterior chamber, total amount of ultrasound energy used, ultrasound energy dissipated close to the CEC, phacoemulsification parameters, free radicals, surgical complications such as posterior capsule rupture and vitreous loss that prolong surgery duration and manipulation, direct contact of surgical device on CEC and hard nucleus, anterior chamber collapse that leads to corneal deformity, IOL-related problems, inadequate surgical experience, and postoperative inflammation.1,2,4,6,7,11,13–16 In the present study, CEC loss in either group was assessed via cell density calculation on a specular microscope. Cell morphology secondary to CEC loss and central corneal thickness, which is not usually parallel, were not taken into consideration.17 Statistically significant CEC loss was detected on the postoperative first and twelfth week as compared to TABLE 3. Preoperative and postoperative corneal endothelial cell density.
Mean Group V
Mean
SD
Mean
SD
p
60.22
4.76
61.90
5.37
0.472
Student’s t test.
DISCUSSION
Group H
TABLE 2. Mean age of the groups.
Age
values were significantly lower than the postoperative first week values both in Group H and in Group V (p50.001) (repeated measures and bonferroni) (Table 3). The mean corneal endothelial count during preoperative period and on the postoperative first and twelfth week is shown as a graph in Figure 1. There was no statistically significant difference between the groups in terms of mean values of differences between the periods (p40.05) (Mann Whitney U test) (Table 4). The amount of irrigation fluid used in the course of phacoemulsification surgery and phacoemulsification time was found statistically similar in both groups (p40.05) (Student’s t test) (Table 5).
Group V
SD
Mean
SD
p*
Preoperative 2525.68 181.85 2514.16 174.59 0.843 Postoperative 1st week 2438.21 198.12 2415.32 197.24 0.723 Postoperative 12th week 2390.74 202.31 2353.47 212.69 0.583 0.001 0.001 pa *Student’s t test. a repeated measures and bonferroni. Seminars in Ophthalmology
Comparison of Phacoemulsification with versus without Viscoelastic
99
2550 2500 2450 Group H
2400
Group V
2350 2300 2250 PREOP
POSTOP 1st week
POSTOP 12th week
FIGURE 1. Preoperative and postoperative corneal endothelial cell density.
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TABLE 4. The mean of the difference between the periods in the groups. Group H
Group V
Absolute change
Mean
SD
Mean
SD
p
Preoperative and postoperative 1st week Preoperative and postoperative 12th week Postoperative 1st and 12th week
87.47 134.95 47.47
73.00 74.79 42.81
98.84 160.68 61.84
51.07 60.01 47.35
0.751 0.138 0.418
Mann Whitney U test. TABLE 5. Time of surgery and mean amount of irrigation fluid used in each group. Group H
Mean irrigation solution used (ml) Phacoemulsification time
Group V
Mean
SD
Mean
SD
p
76.54
28.25
73.84
25.56
684
1.25
0.82
735
1.21
062
Student’s t test.
the preoperative values in both groups, in which the surgical procedure was performed without complication. However, the rate of CEC loss was not statistically significant in either group. No doubt, OVDs provide considerable advantages and facilities in cataract surgery. OVDs are essential devices in cataract surgery owing to their ability to preserve and maintain anatomic spaces, enabling the use of surgical equipment and, sometimes, providing a better view. There are numerous studies reporting that OVDs decrease CEC loss.3,9 However, the number of studies comparing their superiority over each other is limited.18 Preserving and maintaining the anterior chamber during cataract surgery is mandatory, particularly for the protection of CEC. The mini-nuc method developed by Blumenthal19,20 provides this by anterior chamber maintainer (ACM) under irrigation fluid. IOL implantation to the posterior chamber has been possible with ACM through the scleral tunnel. Whereas irrigation and capsulorhexis can be done via cystotome during phacoemulsification, IOL implantation via a cartridge-injector !
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system under irrigation enabled us to conduct the present study. The mean difference between the two groups in terms of phacoemulsification time, phacoemulsification power, and amount of irrigation fluid used was not statistically significant. Irrigation fluid used in both groups was BSS PLUSÕ (Alcon), which is currently considered to be the most suitable one due to its contents.21 Capsulorhexis under fluid is different from the use of OVDs and requires a training period. Access site to the anterior chamber via a cystotome, to which the irrigation fluid is attached, should be so narrow that it can prevent leakage; otherwise, fluctuation of the anterior chamber might cause capsulorhexis to move to the periphery. During capsulorhexis under fluid, the anterior capsule is motile due to turbulence of the fluid, but it would not pose a problem with appropriate maneuvers. Intraocular pressure increment can be seen in the early postoperative period following phacoemulsification due to poorly aspirated OVDs from the anterior chamber; however, we did not observe such a complication in our cases, probably because 1.0% Na-Hyaluronate (PROVISCÕ , Alcon) has been easily removed from the anterior chamber by irrigation/aspiration. IOL was implanted by a cartridge-injector system under fluid in Group H and neither scratch nor another deformation was observed on the IOL surface when examined under a surgical microscope and postoperative biomicroscope after in-the-bag implantation. In the event of such a situation, OVDs would be used while placing IOL into the cartridge-injector system.
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100 S. Kugu et al. The absence of statistically significant difference in terms of CEC loss after phacoemulsification performed with and without OVDs can be assessed in various ways. First, phacoemulsification time was equal in both groups and was relatively short. The endothelial-cell-protecting effect of OVDs might be more remarkable in the case of longer phacoemulsification time. Second, the amount of irrigation fluid used during surgery was low. A higher amount of irrigation fluid will cause CEC to come across with more fluid turbulence, probably leading to increased loss rate. Third, the effect of OVDs might be better in the cases with a CEC number under a certain critical value. The above-mentioned reasons are also the limitations of the present study. There is a need for CEC to be investigated under distinct conditions and situations during cataract surgery. The result does not indicate that the use of OVDs during phacoemulsification has no direct protective effect on CEC, but indicates that many other factors that cause CEC loss during phacoemulsification might be more important. It is beyond dispute that 1.0% sodium-Hyaluronate used during phacoemulsification facilitates the procedure, makes it safer, and provides substantial benefits during the training period. It is known that the use of OVDs during PHACO has a protective effect on CEC. However, which mechanisms play a role in this protective effect is not clearly known and it is assumed that the effect occurs via forming and maintaining the anatomic space. In the present study, we failed to determine the significant protective effect of 1.0% sodiumHyaluronate over BSS PLUSÕ (Alcon) on CEC cell loss during phacoemulsification. However, further studies are needed to investigate the factors and conditions that lead to corneal endothelial cell loss during phacoemulsification.
DECLARATION OF INTEREST The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
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