Assessment of the biometric modifications of the eye in LASIK during suction.

PURPOSE: To study the biometric modifications of the eyeball during suction in Laser assisted in Situ Keratomileusis (LASIK). METHODS: Observational and cross-sectional study. We studied 43 patients who underwent surgery for myopia and myopic astigmatism. Mean age was 38.3 ±â€¯11.5 years, and 19 were female (44.2%). Conventional LASIK surgery with a manual microkeratome was performed. Before and during the suction maneuvre the following parameters were measured using an 11 Mhz biometric probe: aqueous depth (AQD), lens thickness (LT), vitreous cavity length (VCL) and axial length (AXL). Paired t-test was used to compare the biometric measurements before and during suction. RESULTS: The mean spherical equivalent refractive error was -4.5 ±â€¯2.3 diopters. During suction, the AQD did not change significantly (p = 0.231). However, AXL and VCL increased by 0.12 mm and 0.22 mm respectively (p = 0.039 and <0.01) and LT decreased by 0.20 mm (p < 0.01). AXL increased in 42% of the eyes and decreased in 16%, VCL increased in 70% of the eyes and decreased in 9%, and the LT was reduced in 67% of the eyes. CONCLUSIONS: Suction maneuvres during LASIK surgery produce changes of little magnitude in the eye globe, mainly a decrease in LT and an increase in VCL and AXL. Therefore, these modifications are expected to produce minimal anatomic alterations.

Glistening on intraocular lenses: A review.

The glistening in intraocular lenses (IOLs) is a phenomenon in which tiny water-filled microvacuoles (MVs) form within the IOL material, causing light to scatter and create a sparkling or shimmering effect. The presence of glistening is common in many types of IOL materials and models and has been extensively studied in recent years to determine its incidence, risk factors, evolution, and possible clinical relevance. Classically, it has been studied in vitro in the laboratory or by means of photography obtained with a slit lamp, but these were techniques that required either specific technology or an expert explorer, complex image processing, and required a lot of time. In recent years, proposals based on the Scheimpflug camera and optical coherence tomography have emerged to try to simplify the analysis of glistening in IOLs. It has been described that the manufacturing process, the hydrophobic acrylic material, or the time since surgery are risk factors for the appearance of glistening. In addition, many issues related to this phenomenon are still unknown, such as not knowing from what number of points or their size they may have relevance to visual function since different optical phenomena related to glistening have been described on the IOLs.

Unifocal and unilateral pigmented paravenous retinochoroidal atrophy.

Paravenous pigmented chorioretinal atrophy (PPRCA) is a generally multifocal, bilateral and symmetric rare entity associated with autoimmune diseases and other ocular complications. We present the clinical case of a patient with rheumatoid arthritis who attended for pain of several days. He presented decreased visual acuity of the left eye (LE), nodular scleritis and chorioretinal atrophy with pigment accumulation in bone spicules in the inferior temporal vascular arcade and lamellar macular hole (AML). The right eye shows no alterations. LE autofluorescence (AF) shows a hypoautofluorescence lesion with defined edges. Fluorescein angiography (FAG) shows hyperfluorescence consistent with retinal pigmentary epithelial degeneration and blockage in pigment areas. The visual field (VC) reveals a defect in the superior hemifield. This case describes an atypical unifocal and unilateral PPRCA. This variant must be known to make a correct differential diagnosis, as well as to provide adequate prognostic information.

Agreement between optical coherence and Scheimpflug tomography: Vault measurements and reproducibility after implantable collamer lens implantation.

PURPOSE: To evaluate the agreement between Scheimpflug tomography (Pentacam, Oculus) and anterior segment optical coherence tomography (AS-OCT, RTVue 100, Optovue) as well as the reproducibility of each technique in assessing the lens-ICL distance (vault) after implantable collamer lens (ICL) implantation. METHODS: The vault was measured manually with Scheimpflug tomography and AS-OCT. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to determine the reproducibility of measurements and the agreement between them. Multivariate regression analysis was performed to identify predictors of differences in vault measurements between devices. RESULTS: 80 eyes of 46 ICL patients were analyzed. Mean patient age was 33.8±7.4 years (range, 21 to 51), and 27 (59%) were women. The preoperative spherical equivalent refraction ranged from -26 to 8.5 diopters (D). The mean vault measured by AS-OCT was 558.8±240.2µm (range, 162 - 1220) vs. 430.1±215.3µm (range, 0 to 1070) by Pentacam. AS-OCT yielded vault values, on average, 128.1±64.6µm higher than the Pentacam (range, -22 to 293µm). The ICC values for consistency and absolute agreement were 0.960 and 0.928, respectively. Reproducibility of vault measurements was excellent for both devices (ICC≥0.946). Four parameters-vault, pupil diameter (PD), PD differences between devices, and preoperative spherical equivalent refraction-were significant predictors of differences in vault measurements (adjusted-R2=0.412; P<0.001). CONCLUSIONS: Agreement between AS-OCT and Pentacam for vault measurement was good. Vaults were higher when measured by AS-OCT. These differences are clinically relevant, and therefore these devices cannot be used interchangeably to measure vault.

Assessment of changes in the macula and optic nerve head using optical coherence tomography in patients with attention deficit hyperactivity disorder. / Evaluación de los cambios en la mácula y en el nervio óptico mediante tomografía de coherencia óptica en pacientes con trastorno por déficit de atención e hiperactividad.

INTRODUCTION: To assess if there are any differences in macular and papillary thickness using optical coherence tomography (OCT) in patients with attention deficit hyperactivity disorder (ADHD) compared with a control group, including if there are differences between ADHD patients with and without treatment. METHODS: Prospective observational study including 92 eyes of 46 patients divided into 2 groups: 46 eyes of 23 patients with ADHD, and a control group of 46 eyes of 23 healthy patients. The group of patients with ADHD was subdivided into those on treatment with methylphenidate (n=28) and those not on treatment (n=18). The macular thickness, the ganglion cell complex (GCC), and the retinal nerve fibre layer (RNFL) at the papillary level were measured in 12 sectors. RESULTS: A lower central macular thickness was observed in the ADHD patients than in the controls (257.4±20µm versus 267.5±20µm, P=.013), with no differences observed in the GCC (P=.566), or in the RNFL (P=.095). There were no differences in the patients with ADHD with and without treatment, as regards macular thickness and the GCC (P=.160 and P=.375 respectively), but a lower foveal thickness (P=.018) and RNFL in 5/12 sectors at the papillary level (P=.033) were observed in those without treatment. CONCLUSIONS: A lower macular thickness was observed in patients with ADHD than in controls. In addition, patients with ADHD without treatment had a lower thickness of the fovea and RNFL than those patients on treatment.

Pseudoexfoliation signs in the anterior segment assessed by optical coherence tomography and Scheimpflug device. / Evaluación de los signos de la pseudoexfoliación en el segmento anterior mediante tomografía de coherencia óptica y cámara de Scheimpflug.

OBJECTIVE: To evaluate different anterior segment parameters in eyes with pseudoexfoliation (PSX), fellow eyes, and controls using optical coherence tomography and a Scheimpflug imaging system. METHODS: Three groups were studied: 44 eyes of 44 patients with PSX, 30 clinically unaffected fellow eyes, and 148 eyes of 148 healthy controls. The anterior chamber depth and volume, corneal volume and thickness, pupil diameter and corneal densitometry were measured using a Scheimpflug imaging system (Pentacam, Oculus Inc.; Wetzlar, Germany). The angle width, the length and area of the trabecular meshwork, and the iris thickness were measured using an optical coherence tomography RTVue 100 device (Optovue, Fremont, CA, USA). The presence of PSX deposits was also assessed by OCT. RESULTS: There were no differences in the anterior chamber volume or depth in the corneal volume or central thickness (P≥.228). The corneal densitometry was similar between PSX and fellow eyes; however it was greater than in the control group (P<.001). As regards the parameters measured by OCT, there were no differences in the angle width or in the trabecular meshwork size between the 3 groups; however, the iris was thinner in controls (P=.005). In all patients the PSX deposits were correctly visualised by OCT after the identification by biomicroscopy. CONCLUSIONS: There were no differences in the anterior segment biometric measurements between patients with PSX and controls, although the corneal densitometry and iris thickness were greater in the PSX and fellow eyes groups.

Remifentanil: A help in topical strabismus surgery. / Remifentanilo: una ayuda en la cirugía tópica del estrabismo.

OBJECTIVE: To analyze the analgesic effect of remifentanil, side effects and complications in topical strabismus surgery. To study the results of strabismus surgery with this type of anesthesia. MATERIAL AND METHOD: Retrospective descriptive study. We included 39 patients undergoing strabismus surgery with topical anesthesia and analgesia-based sedation with remifentanil. The data of the anesthetic and surgical technique, surgical results and stability of the deviation angle were analyzed. RESULTS: Thirty nine patients (54% women) were included, the average age was 37,4years old. The mean follow-up was 24,5months. The preoperative diagnoses were exotropia (21 patients), esotropia (12), paresis strabismus (4) and Duane's Syndrome (2). 15% patients had preoperative diplopia and 13 had received previous treatments. The dose range of remifentanil used was 0.05 to 0.2µg/kg/min. The side effects presented were 2 cases of vomit and one of bad collaboration during the intraoperative adjustment, one of the patient reported pain and one case of thoracic rigidity was reported. 79% of the patients obtained a good surgical result and 82% reported being satisfied with the results. The reintervention rate was 5%. CONCLUSIONS: Analgesia-based sedation with remifentanil is an useful complement to topical strabismus surgery because it reduces pain during surgery and allows the patient to collaborate during intraoperative adjustment due to its pharmacokinetic characteristics.