International Ophthalmology 24: 257–258, 2001.© 2003 Kluwer Academic Publishers. Printed in the Netherlands.

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Fluorescein-assisted viscodissection for easier phacoemulsification

Mohamed Hosny, Sherif Gamal Eldin & Hesham HosnyOphthalmology Department, Cairo University, Egypt

Accepted 6 February 2003

Key words: phacoemulsification, hydrodissection, fluorescein, vital stains

Abstract

Title: Fluorescein-assisted viscodissection for easier phacoemulsification. Settings: Department of Ophthalmology,Cairo University. Purpose: The description of a new surgical technique to help overcome difficulties in the learningcurve of phacoemulsification. Methods: A mixture of Fluorescein 0.25% and methyl cellulose 0.25% is used forhydrodissection. Standard phacoemulsification is then continued until the initial groove reaches the plane betweenthe lens cortex and the capsule when the fluorescein flows towards the anterior chamber in a Green Smoke. Thissign indicates a proper depth for attempting to crack the nucleus into two halves.

Introduction

Today phacoemulsification is the standard procedurein cataract surgery. Although in expert hands it issafe, it requires a longer learning period than stand-ard extracapsular cataract extraction. Proper coachingsolves most of the difficulties, but some problemsare commonly encountered with all trainees. One ofthese problems is the depth of the initial groove beforecracking the nucleus. Too shallow a groove will leadto failure of cracking of the nucleus, groove distortion,tearing of the capsulorhexis edge or extensive manip-ulations leading to posterior capsular rupture. On theother hand too deep a groove will lead to openingof the posterior capsule by the phaco probe, espe-cially paracentrally where the thickness of the lensis less than in the center. Proper groove depth re-mains dependant on proper judgment from adequateexperience. Until this adequate experience is acquired,we recommend a special technique to be adopted bybeginners for proper groove depth and safe cracking.

Surgical technique

After a clear corneal incision, side port incision andcapsulorhexis, a mixture of Fluorescein 0.25% andhydroxypropyl methyl cellulose 0.25% is injected just

tinder the edge of the capsulorexis with a 27 gaugeneedle until the wave is seen crossing under the nuc-leus and filling the area between the lens contents andthe posterior capsule (Figure 1). Cleaning of the an-terior chamber from the excess mixture is then donewith a Simcoe irrigation aspiration canula. Groovesculpting is started with the phaco probe using 70%phaco power, 10 mmHg vacuum and 10 cc/mm flowrate. The groove is then deepened until a level of depthis reached where Fluorescein is seen floating towardsthe anterior chamber in a characteristic Green Smokesign (Figure 2). Cracking at this stage is attempted andis always successful. The two halves are then dealtwith one at a time, with a stop and chop techniqueusing a Neuhann chopper and pulsed phaco with 250mmHg vacuum, 60% phaco power and 20 cc/mm flowrate. After finishing the nucleus and epinucleus, irrig-ation/aspiration of the cortex is done and a foldableintraocular lens is implanted.

Discussion

Continuous assessment of the depth of the initialgroove during phacoemulsification is very important.Optimal depth for cracking remains difficult to decideon early the learning period. Too shallow a groove willlead to failure of cracking, distortion of the groove

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Figure 1.

Figure 2.

and excessive manipulations. Too deep a groove mayendanger opening the posterior capsule, especiallyparacentrally where the thickness of the crystallinelens is not as deep as the center. Hydrodissection isan essential and basic step in the procedure and drugsadded to BSS used for this step have been used in otherstudies. Preservative-free lidocaine has been addedto BSS used for hydrodissection as a method for in-tracameral anesthesia [1]. Many vital stains have beenused intracamerally to study their staining effect onthe anterior capsule and their potential toxicity on thecorneal endothelium. Trypan Blue 0.05%, althoughpopular, has been shown to have teratogenic effectsand should be avoided in fertile and pregnant women[2, 3].

Good visibility and low endothelial toxicity wereachieved with Methylene green 0.5%, Gentian Violet0.05% and Briliant Cresyl Blue 0.5% [4, 5]. Indocyan-ine Green was also used in other studies and was foundto cause minimal corneal endothelial cell loss [6].

Fluorescein has been extensively used for variousextra and intraocular diagnostic tools [7, 8]. The useof intracameral Fluorescein has been shown to be themost physiological dye on the corneal endothelium[9]. Fluorescein was used in combination with methyl-cellulose to keep the mixture in place from the stepof hydrodissection until the groove is completed andthe space between the capsule and the lens contents isreached by the phaco probe. If it was used with BSS,it would have been washed slowly by the continuousirrigation/aspiration fluids during phaco and, by thetime the groove reaches the bottom of the lens materialno or very little dye would still be left to be seen as aGreen Smoke sign.

We have employed this technique with our traineesin the first twenty cases of phacoemulsification withsuccess, and we believe that it is useful early in thelearning period.

References

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2. Norn MS. Methylene blue (methylthionine) vital staining of thecornea and conjunctiva. Acta Ophthalmol (Copenh) 1967; 45:347–358.

3. Senior W. Staining of animal tissue with the dye base of methyl-ene green in benzene to facilitate identification and selection ofmaterial. Stain Technol 1969; 44: 269–271.

4. Melles GRJ, Waard PWT, Pameyer JH, Beekhius WH. Trypanblue capsule staining to visualize the capsulorhexis in cataractsurgery. J Cataract Refract Surg 1999; 25: 7–9.

5. Gamal Eldin SA, El Mehelmy EM, El Shazli EM, MostafaYMS. Experimental staining of the anterior lens capsule inalbino rabbits. J Cataract Refract Surg 1999; 25: 1289–1294.

6. Horiguchi M, Miyake K, Ohta I, Ito Y. Staining of the lenscapsule for circular capsulorhexis in cataract surgery. J CataractRefract Surg 1999; 25: 7–9.

7. Mishima A, Gasset A, Klyce SD Jr, Baum JL. Determinationof tear volume and tear flow. Invest Opthalmol Vis Sc 1966; 5:264–276.

8. Norton EW, Gutman F. Diabetic retinopathy studied by fluor-escein angiograph. Trans Am Ophthalmol Soc. 1965; 63:108–128.

9. Carlson KH, Bourne WM. The clinical measurement of en-dothelial permeability Cornea 1988; 7: 183–189.

Address for correspondence: M. Hosny, 10 Lebenon Street, Mo-handeseen, Giza, EgyptTel: +2012 2112617; E-mail: gozreem@hotmail.com