Suggestion of serious incidents in medical devices used in anterior segment surgery. Proposing ideas (II).

The entry into force of the regulation on medical devices obliges ophthalmologists to identify and report possible serious incidents arising from their use. Faced with the doubts that may arise about what can or cannot be considered a serious incident, a working group of members of the Spanish Society of Refractive and Implant Eye Surgery (SECOIR) and the ophthalmology and vision sciences cluster (Cluster4Eye), have prepared a consensus document that aims to guide ophthalmologists on some of the incidents that, in the experience of the work team, are not common or can cause serious damage to the patient's function in relation to the use of medical devices. Incidents related to the use of viscoelastics, anterior capsule dyes, intraocular lenses, and other items used in anterior segment surgery have been addressed.

Severe epithelial ingrowth after pars plana vitrectomy ten years after LASIK relifting.

Epithelial ingrowth is one of the most significant complications of Laser in Situ Keratomileusis (LASIK) refractive surgery. We present the case of a 72-year-old male with a history of myopic LASIK (1999), who underwent cataract surgery and a second thin LASIK sub-Bowman flap to correct refractive error. Then, three months after pars plana vitrectomy for an epiretinal membrane, the patient complained of progressive vision loss. A diffuse haze of the corneal stroma that did not exist before surgery was observed. As the main suspicion was epithelial ingrowth, the flap was lifted and meticulous de-epithelialization of the stromal bed was performed. Mitomycin C 0.02% was applied, the flap was sutured with 10-0 Nylon, and a bandage contact lens was placed. The epithelialization of the interface after vitrectomy in a patient with LASIK could occur even when it is a rare complication and without obvious flap traumatism.

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.

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.

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.

Agreement between Pentacam and optical coherence tomography in the assessment of iridocorneal angle width in a large healthy population.

PURPOSE: To analyze the agreement between Pentacam and optical coherence tomography (OCT) in the assessment of trabecular-iris angle (TIA) width in a large population of normal subjects. METHODS: A cross-sectional study was performed in 989 right eyes of 989 healthy subjects. The trabecular-iris angle (TIA) was measured in the temporal and nasal quadrants using the Pentacam (Oculus, Wetzlar, Germany), a device based on Scheimpflug technology and RTVue 100 OCT (Optovue, Fremont, CA, USA). Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to evaluate agreement between these devices. RESULTS: Mean age was 49.1±15.2 years (18-84); 61% were women and spherical error range was -14 to 8.25. TIA could be measured by OCT in 94.9% and 94.1% in the temporal and nasal quadrants, with a mean value of 35.8±13.2 degrees (2.5-78.7) and 35.7±12.9 degrees (2.2-76.8) respectively. TIA was able to be measured by Pentacam in 95.2% and 95% in the temporal and nasal quadrants and means were 35.7±7.3 degrees (11-74.2) and 36.4±8.2 degrees (14.5-64) respectively. An ICC of 0.378 (95% confidence interval [CI], 0.322-0.431) and 0.589 (95% CI 0.546-0.629) for the temporal and nasal quadrants was obtained, showing moderate agreement between the devices. Bland-Altman plots revealed that, compared with OCT, Pentacam tends to overestimate measurements in narrow angles and underestimate these in open angles. CONCLUSIONS: Agreement between OCT and Pentacam was mediocre, indicating the two devices are not interchangeable when used to measure angle width.

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.

[Prevalence of diabetic retinopathy in the Regional Comunity of Extremadura. 1997-2001 (Extremadura Project to Prevent Blindness)]. / Prevalencia de retinopatía diabética en la Comunidad Autónoma de Extremadura. 1997-2001 (Proyecto Extremadura para Prevención de la Ceguera).

OBJECTIVE: To establish the prevalence of diabetic retinopathy (DR), types and risk factors in a diabetic population in Extremadura. METHODS: A cross-sectional study, with prospective data collection, was performed between 1997 and 2001 on 3,114 randomly selected diabetic patients belonging to 13 Diabetologic Assistance Centers. We evaluated: age, gender, type, treatment, duration of diabetes and blood pressure levels. Two color fundus photographs were taken and ophthalmoscopy was performed on both eyes. Data were analyzed using SPSS (11.5). RESULTS: The mean age of the patients was 63.8 (SD13.4) years, 7.5% were type 1 diabetics, 31.1% were insulin-treated and 46.0% had elevated blood pressure. Prevalence of DR was 35.7%, macular edema: 5.6% and proliferative DR: 5.3%. Multivariate analysis showed that type 1 diabetics have a DR frequency 1.79 times higher than type 2 diabetics (ORaj 1.79; IC 95% 1.22-2.63; p=0.003). Patients who have been diabetic for 5-10 years have a frequency 2 times higher (ORaj 2.00; IC 95% 1.62-2.45; p<0.001), patients diabetic for more than 15 years have a frequency 5.48 times higher (ORaj 5.48; IC 95% 4.33-6.93; p<0.001) than patients who have been diabetic for less than 5 years. The frequency of DR in patients aged more than 60 years is 23% higher than those under that age. (ORaj 1.23; IC 95% 1.01-1.50; p=0.045). CONCLUSIONS: 37.5% of the diabetic population in Extremadura is affected by diabetic retinopathy. New analyses are necessary in this population to detect the existence of other high risk subgroups in order to reduce these high prevalence levels.