[Results of treatment of undercorrections of radial keratotomy by Excimer laser]. / Résultats du traitement des sous-corrections de kératotomie radiaire au laser Excimer.

Photorefractive keratectomy (PRK) was performed with Excimer Laser after undercorrected radial keratectomy in 21 eyes of 15 patients (maximum 8 incisions, 3 mm optical zone). There was at least a 6-month interval between the two procedures. At the time of PRK, the mean age of the patients was 31 years and the mean spherical equivalent -2.3 D. Mean follow-up after PRK was 7.5 months; 10 eyes were followed for more than one year. Quite satisfactory results were obtained since PRK was effective in 88% (eyes with uncorrected visual acuity of 20/40 or better); predictability at +/- 1 D was 89%. Stable refractiveness was achieved at 3 months. The procedure is safe: there was no loss of best corrected visual acuity nor haze at one year. Other means of treating for undercorrection after refractive keratectomy were discussed in comparison with this technique.

[Clinical results of photo-refractive keratectomy. Preliminary study with 57 eyes]. / Résultats cliniques de la photo-kératectomie réfractive. Etude préliminaire sur 57 yeux.

The authors report their personal experience of Photo-Refractive Keratectomy (PRK) with an Excimer Laser based on the study of 57 sighted eyes, 24 with more than six months and 11 with more than one year of follow-up. The initial myopia ranged from -1 to -13 D with a spherical average equivalent of -6.36 D. The photo-ablations, performed with the Excimer of the Summit Company, ranged from 3.7 to 5 mm of diameter and 16 to 76 mu in depth. Results are reported overall and for sub-groups of myopia (A < or = -3 D, -3 D < B < or = -7 D, -7 D, < C). They were satisfactory since at one year 45% of eyes obtained a visual acuity without correction > or = 5/10 and 64% of eyes were within one dioptre of emmetropia; stability of refraction from six months to one year is close to 80%; safety was good since no patient has lost a line of best spectacle corrected visual acuity at one year and we only found one case of haze at 1+ without visual loss. These encouraging results lead the authors to pursue their study and to include new patients to obtain larger groups in order to establish statistically significant differences for parameters such as age, sex, myopia, keratometry, depth and optical zone of photo-ablation.

Effect of preoperative YAG laser anterior capsulotomy on the incidence of posterior capsule opacification: ten year follow-up.

One hundred twenty-two patients, who were followed for ten years, had bilateral extracapsular cataract surgery with implantation of J-looped posterior chamber lenses between 1980 and 1981. On the first eye an anterior capsulotomy was performed with a pico-second YAG laser 12 to 20 hours before surgery; on the second eye a capsulotomy was performed manually at the time of surgery. Four of the eyes (3.27%) with laser capsulotomies had opacified posterior capsules after ten years; 61 of the eyes (50.00%) with manual capsulotomies had opacified capsules that had to be opened with a YAG laser.

Use of a pulsed picosecond Nd: YAG laser in 6,664 cases.

We used a modulated picosecond Nd:YAG laser to perform preoperative anterior capsulotomies and posterior capsulotomies in eyes with and without an intraocular lens, and to cut a variety of cyclitic membranes, iridocapsular adhesions, and vitreous traction bands in more than 6,500 cases. The complications were transient bleeding when vascularized tissues were cut because the laser does not coagulate, temporary anterior chamber inflammation, and transient increased intraocular pressure. The last two were caused by released lens material and shock wave side effects.

Methylcellulose instead of Healon in extracapsular surgery with intraocular lens implantation.

Methylcellulose 1% was used in the anterior chamber to facilitate posterior chamber lens implantation at the time of extracapsular cataract extraction. In parallel series with similar preoperative endothelial cell counts, 70 eyes implanted under methylcellulose had a mean central endothelial cell loss of 8 +/- 5.3% at 8 to 12 weeks postoperative, whereas 63 eyes implanted under an air bubble lost a mean 25.3 +/- 14.6% (P less than 0.001). No differences in postoperative visual acuity, intraocular pressure, or inflammation were noted. A YAG laser preoperative anterior capsulotomy was used in all cases, and may have contributed to overall preservation of endothelial cells.

Intraocular lens implantation in unilateral congenital cataract: a preliminary report.

We performed pars plana lensectomy with secondary anterior chamber intraocular lens (IOL) implantation in 32 cases of unilateral congenital cataract with otherwise normal appearing eyes. Five of the 12 patients old enough to respond achieved a visual acuity of 20/60 or better with evidence of fusion. We advocate operating within the first few months of life to lessen amblyopia.

Use of a pulsed neodymium Yag laser (picosecond) to open the posterior lens capsule in traumatic cataract: a preliminary report.

The use of an ultra short Nd Yag laser pulses is described for the opening of secondary traumatic cataract and iridocapsular synechiae. Both pigmented and non pigmented ocular tissue were cut without causing adverse thermal effects and without opening the eye. The laser instantaneous release of energy causes total ionization of the medium and formation of a plasma, followed by a hydrodynamic shock wave originating at the energy zone boundary. The temperature at the site of the laser contact cannot exceed 2 X 10(-3) degrees C, which is not harmful to the eye. Further, this procedure requires no anesthesia and does not involve introduction of foreign material into the eye. The degree of aiming accuracy, the very small diameter of the beam (50 microns) make the laser so precise that it virtually eliminates the risk of damage to the eye and/or the intraocular lens.