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Use of a pulsed neodymium-Yag laser for anterior capsulotomy before extracapsular cataract extraction
Use of a pulsed neodymium-Yag laser for anterior capsulotomy before extracapsular cataract extraction Daniele Aron-Rosa, M.D. Paris, France ABSTRACT Preoperative opening of the anterior capsule facilitates extracapsular cataract extraction by reducing surgical manipulations in the anterior chamber and shortening the surgical procedure. The anterior capsule is easy to collect or aspirate. The penetration of the aqueous humor facilitates extraction of the nucleus and makes the removal of the cortex, which detaches spontaneously, very easy and safe. Key words: laser capsulotomy, extracapsular extraction, neodymium-Yag laser
The ophthalmologic operative laser developed by the Trousseau Hospital research team delivers infrared light impulses lasting less than 10- 10 seconds. 1 These impulses act in a purely mechanical way through the process of optical strain (Fig. 1) and cause no thermal effects. The action radius of this neodymium-Yag laser is from 100 to 150 microns in the plane perpendicular to its beam and up to 0.5 mm around the beam's focal point. There is therefore little danger of damaging the corneal endothelium when the laser beam is used to perform an anterior capsulotomy before implant insertion. SUBJECTS AND METHODS Two hundred patients, ages 12 to 91, underwent laser opening of the anterior capsule one to 24 hours before extracapsular cataract extraction and insertion of an IOL. Each patient was given 0.50 g of indomethacin per day for six weeks preoperatively. In all cases, a solution of Mydrilate and 10% neosynephrine was administered to maximally dilate the pupil. Neither local anesthesia nor a contact lens was required for this procedure. The patient was seated at the laser slitlamp, as for argon laser use, and the laser beam was focused on the anterior capsule. The capsule was opened by a continuous series of 100 to 200 shots, the shape of the opening depending on the IOL to be inserted and on the surgeon's preference (Fig. 2). The laser was also used to fragment the lens if the lens nucleus was hard. A specular microscope (Heyer-Schulte) was used to perform corneal endothelial cell counts immediately before and after laser treatment. Intraocular pressure was measured before and then regularly for several hours after completion of the procedure.
LOW ENERGY ULTRA-SHORT DURATION FINE FOCALIZATION
POWER DENSITY> 10 Watts/cm 2
OPTICAL STRAIN PLASMA FORMATION
I OPAQUE PLASMA PROVIDING PROTECTIVE SCREEN FOR RETINA
'\ SHOCK WAVE FORMATION CAUSING OBSTRUCTION
Fig. 1 (Aron-Rosa and Aron). Mechanism of action of neodymiumYag laser on intraocular material.
Fig. 2 (Aron-Rosa and Aron). Square capsulotomy performed with neodymium-Yag laser 12 hours prior to cataract extraction. Note retraction of anterior capsule.
Presented at the Fourth U.S. Intraocular Lens Symposium, Los Angeles, California, March 27, 1981. Reprint requests to Dr. Aron-Rosa, Eye Clinic, Hospital Trousseau, 26 av du Dr. Arnold Netter, 75012, Paris, France. 332
AM INTRA-OCULAR IMPLANT SOC J-VOL. 7, FALL 1981
RESULTS There were no changes in endothelial cell counts and no evidence of random shots on Descemet's membrane. lOP increased in the 20 patients with soft intumescent cataracts, who underwent laser treatment 24 hours before IOL insertion. In each of these cases applanation tonometry recorded elevated pressure three to four hours after opening of the anterior capsule. lOP never exceeded 35 mm Hg and was invariably reduced in a few hours with timolol drops and/or acetazolamide. These eyes had no special intraoperative difficulties. Fifteen patients with soft cataracts underwent laser opening of the capsule two hours before cataract extraction. lOPs were not elevated in these eyes after laser treatment. lOPs also remained stable in the 105 remaining patients with subcapsular cataracts, hard nuclei, or senile corticonuclear cataracts, even when the capsule was opened the day before surgery. Slitlamp examination showed no corneal edema in any case, although 15 patients had lens material in the anterior chamber. There was no cellular reaction in the aqueous humor. In all cases the postoperative course was unevent-
ful. Over a follow-up period of six months to two years after IOL insertion, there were 14(7%) cases of secondary opacification of the posterior capsule, three (1.5)% cases of cystoid macular edema, and only one (0.5%) case of retinal detachment. The detachment occurred one year postoperatively. CONCLUSION Laser opening of the anterior capsule before extracapsular cataract surgery is a safe, noninvasive procedure which requires no local anesthesia. It reduces time in surgery and facilitates extracapsular extraction and removal of the cortex, thereby decreasing the incidence of secondary opacification. The capsule should be opened several hours to one day before surgery if the lens nucleus is hard, and less than three hours before surgery if the cataract is liquid.
REFERENCES 1. Aron-RosaD, AronJ, GriesemannJC: Use of the neodymiumYag laser to open the posterior capsule after lens implant surgery: a preliminary report. AIOIS] 6:352, 1980
AM INTRA-OCULAR IMPLANT SOC J-VOL. 7, FALL 1981
333
The ophthalmologic operative laser developed by the Trousseau Hospital research team delivers infrared light impulses lasting less than 10- 10 seconds. 1 These impulses act in a purely mechanical way through the process of optical strain (Fig. 1) and cause no thermal effects. The action radius of this neodymium-Yag laser is from 100 to 150 microns in the plane perpendicular to its beam and up to 0.5 mm around the beam's focal point. There is therefore little danger of damaging the corneal endothelium when the laser beam is used to perform an anterior capsulotomy before implant insertion. SUBJECTS AND METHODS Two hundred patients, ages 12 to 91, underwent laser opening of the anterior capsule one to 24 hours before extracapsular cataract extraction and insertion of an IOL. Each patient was given 0.50 g of indomethacin per day for six weeks preoperatively. In all cases, a solution of Mydrilate and 10% neosynephrine was administered to maximally dilate the pupil. Neither local anesthesia nor a contact lens was required for this procedure. The patient was seated at the laser slitlamp, as for argon laser use, and the laser beam was focused on the anterior capsule. The capsule was opened by a continuous series of 100 to 200 shots, the shape of the opening depending on the IOL to be inserted and on the surgeon's preference (Fig. 2). The laser was also used to fragment the lens if the lens nucleus was hard. A specular microscope (Heyer-Schulte) was used to perform corneal endothelial cell counts immediately before and after laser treatment. Intraocular pressure was measured before and then regularly for several hours after completion of the procedure.
LOW ENERGY ULTRA-SHORT DURATION FINE FOCALIZATION
POWER DENSITY> 10 Watts/cm 2
OPTICAL STRAIN PLASMA FORMATION
I OPAQUE PLASMA PROVIDING PROTECTIVE SCREEN FOR RETINA
'\ SHOCK WAVE FORMATION CAUSING OBSTRUCTION
Fig. 1 (Aron-Rosa and Aron). Mechanism of action of neodymiumYag laser on intraocular material.
Fig. 2 (Aron-Rosa and Aron). Square capsulotomy performed with neodymium-Yag laser 12 hours prior to cataract extraction. Note retraction of anterior capsule.
Presented at the Fourth U.S. Intraocular Lens Symposium, Los Angeles, California, March 27, 1981. Reprint requests to Dr. Aron-Rosa, Eye Clinic, Hospital Trousseau, 26 av du Dr. Arnold Netter, 75012, Paris, France. 332
AM INTRA-OCULAR IMPLANT SOC J-VOL. 7, FALL 1981
RESULTS There were no changes in endothelial cell counts and no evidence of random shots on Descemet's membrane. lOP increased in the 20 patients with soft intumescent cataracts, who underwent laser treatment 24 hours before IOL insertion. In each of these cases applanation tonometry recorded elevated pressure three to four hours after opening of the anterior capsule. lOP never exceeded 35 mm Hg and was invariably reduced in a few hours with timolol drops and/or acetazolamide. These eyes had no special intraoperative difficulties. Fifteen patients with soft cataracts underwent laser opening of the capsule two hours before cataract extraction. lOPs were not elevated in these eyes after laser treatment. lOPs also remained stable in the 105 remaining patients with subcapsular cataracts, hard nuclei, or senile corticonuclear cataracts, even when the capsule was opened the day before surgery. Slitlamp examination showed no corneal edema in any case, although 15 patients had lens material in the anterior chamber. There was no cellular reaction in the aqueous humor. In all cases the postoperative course was unevent-
ful. Over a follow-up period of six months to two years after IOL insertion, there were 14(7%) cases of secondary opacification of the posterior capsule, three (1.5)% cases of cystoid macular edema, and only one (0.5%) case of retinal detachment. The detachment occurred one year postoperatively. CONCLUSION Laser opening of the anterior capsule before extracapsular cataract surgery is a safe, noninvasive procedure which requires no local anesthesia. It reduces time in surgery and facilitates extracapsular extraction and removal of the cortex, thereby decreasing the incidence of secondary opacification. The capsule should be opened several hours to one day before surgery if the lens nucleus is hard, and less than three hours before surgery if the cataract is liquid.
REFERENCES 1. Aron-RosaD, AronJ, GriesemannJC: Use of the neodymiumYag laser to open the posterior capsule after lens implant surgery: a preliminary report. AIOIS] 6:352, 1980
AM INTRA-OCULAR IMPLANT SOC J-VOL. 7, FALL 1981
333