[Surgical solution to vitreous floaters visual problem]. / Solución quirúrgica al problema visual de los cuerpos vítreos flotantes.

PURPOSE: To evaluate the role of 25 gauge pars-plana vitrectomy (25G-PPV), after a careful patient selection, when we find highly annoying vitreous floaters and to question if this is an ethical therapeutic option. METHODS: A retrospective study of eight eyes (seven patients) aged 58+/-14 years old (range 42-78) high myopes and pseudophakes who underwent 25G-PPV. Clinical data and visual acuity were studied at six to twelve months follow-up. Health-related functioning and quality of life was measured with the 39-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-39). RESULTS: No complications were observed. All patients were satisfied. Safety at third month was 100% and 37.5% improved one or more lines of visual acuity. CONCLUSIONS: Vitreous floaters can be often undervaluated by ophthalmologists, resulting in no intervention. Conventional 20 gauge PPV after a carefully examination can be an effective option for some authors. 25G-PPV incorporates also advantages as the early recovery, with little complications in pseudophakic eyes.

[Corneal graft data collection: evaluation of results 1995-2000]. / Los registros en el trasplante de córnea: evaluación de resultados 1995-2000.

PURPOSE: To examine the collection of data from the corneal grafts performed between 1995 and 2000, thus providing a long term follow-up. METHODS: Records of corneal grafts were made according to the following design and divided into three basic groups: 1a) donor data: age, storage time, endothelial density, ABO group; 1b) recipient data: age, ABO group, sight threatening pathology, diagnosis, visual acuity, corneal oedema, inflammation, vascularisation; 2) surgery data: surgery type, graft size, suture, intraocular lens, vitrectomy, complications; 3) data at first month and at each year follow-up: visual acuity, astigmatism, endothelial density, graft rejection and complications. A retrospective study of data collection percentage was performed. RESULTS: Although 100% of data from donors and recipients was collected, some data such as ABO group was not available in all cases. First indication was keratoconus and bullous keratopathy. Mean visual acuity at first year was 0.31, collected in 60% and endothelial density, 2,223 cls/mm2, available in 26.6 percent. CONCLUSIONS: A good basic data collection improves the long-term follow-up for corneal grafts. Further analysis in the future of this data will be helpful for clinical audit.

[Optimization of an individualized LASIK surgery. Geometric ray tracing model]. / Optimización de una intervención de cirugía LASIK individualizada. Modelo óptico de trazado de rayos.

PURPOSE: To develop an objective calculation method that is able to provide a customized surgical correction that allows the patient to reach the emmetropia and the maximum visual acuity after the surgery. METHODS: The study included 187 eyes with myopia or myopic astigmatism that underwent LASIK. The optical characterization of each eye was developed by a complete theoretical model based in Le Grand eye, in which the measured values of radii and thicknesses of the different surfaces have been substituted. By means of a geometric ray tracing, the surgery has been simulated by changing the anterior corneal radius and the corneal thickness within the optical zone to obtain its influence in the ocular image and the visual acuity. We considered the surgery to be <> when the residual equivalent refraction was between 0 and +0.5 D. RESULTS: An interval for the final corneal radius is proposed for each eye in order to reach the best visual acuity (optimal interval). The position of the post-surgical radius in this interval has been related with the success of the surgical process. CONCLUSIONS: An objective method for LASIK has been proposed: i) it calculates a personalized surgical plan that allows the patient to reach the best visual quality, and ii) it can be used as a reference by the surgeon to design his nomogram and to decrease his learning curve.

Geometric ray tracing analysis of visual acuity after laser in situ keratomileusis.

PURPOSE: Using a geometric ray tracing model, we explain the increase in visual acuity observed in myopic patients after laser in situ keratomileusis (LASIK). METHODS: This study included 37 eyes of 23 patients who underwent LASIK. All patients had myopia and a spectacle-corrected visual acuity of 0.95 or worse. Clinical tests included biometry, corneal topography, pachymetry, and refraction (with and without cycloplegia). Calculations were made by tracing rays through all the refractive surfaces of the eye based on a Le Grand-type theoretical model of the whole eye. RESULTS: Comparison of spectacle-corrected visual acuity of the eye before surgery, the size of the blur circle calculated by ray tracing, and the magnification for the ocular system facilitated a numerical criterion to assess visual acuity by geometric calculation. This criterion was applied to myopic eyes that underwent LASIK, and the maximum increase in spectacle-corrected visual acuity was predicted. An actual increase in visual acuity of approximately 40% of the predicted maximum was observed in patients. CONCLUSIONS: With geometric ray tracing, it was possible not only to obtain an estimate of the visual acuity before LASIK but also to assess the value of the maximum and probable increases in visual acuity after LASIK.

Intraocular lens implantation and laser in situ keratomileusis (bioptics) to correct high myopia and hyperopia with astigmatism.

PURPOSE: To analyze the refractive outcome of moderate to high myopic and hyperopic patients with astigmatism who underwent programmed refractive surgery; first lens phacoemulsification with intraocular lens implantation and 3 months later, laser in situ keratomileusis (LASIK). METHODS: Four men and eight women (22 eyes) with a mean age 47.3 years (range, 38 to 75 yr), and an average spherical equivalent refraction of -11.76 D and +5.22 D and (range, -17.50 to +8.50 D) underwent two refractive procedures. First, phacoemulsification of the lens with a self-sealing incision through clear cornea on the steepest topographic axis and implant of a monofocal intraocular lens in the bag was performed by two experienced surgeons. Second, LASIK was performed with the Nidek EC-5000 excimer laser and the Moria LSK-One microkeratome, by one surgeon. Eyes were divided into two different groups. In the first group, the IOL implanted was calculated to leave the eye slightly myopic, with final correction to be achieved with LASIK. In the second group, the IOL implanted was calculated to achieve emmetropia, correcting any residual refractive error with the laser. RESULTS: After surgery, mean spherical equivalent refraction was +0.26 D (range, -0.375 to +1.50 D). Predictability of refractive outcome: 0 to -1.00 D, 63.63%; +0.25 to +1.00 D, 31.80%; +1.25 to +2.00 D, 4.54%. Mean residual refractive astigmatism was 0.30 D (range, 0 to 1.50 D). Uncorrected visual acuity of 20/20 or better was achieved in 18.3% of eyes; 20/40 or better in 81.8%. No eyes lost two or more Snellen lines of visual acuity and no adverse effects were observed. CONCLUSIONS: Bioptics (phacoemulsification with IOL implantation followed 3 months later by LASIK with the Nidek EC-5000 excimer laser) for correction of moderate to high myopia and hyperopia, with astigmatism, enabled us to treat the total refractive error and adjust final outcomes.