Quantitative OCT-based corneal topography in keratoconus with intracorneal ring segments.

Custom high-resolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT) was used to characterize three-dimensionally (3-D) corneal topography in keratoconus before and after implantation of intracorneal ring segments (ICRS). Previously described acquisition protocols were followed to minimize the impact of the motions of the eye. The collected set of images was corrected from distortions: fan (scanning) and optical (refraction). Custom algorithms were developed for automatic detection and classification of volumes in the anterior segment of the eye, in particular for the detection and classification of the implanted ICRS. Surfaces were automatically detected for quantitative analysis of the corneal elevation maps (fitted by biconicoids and Zernike polynomials) and pachymetry. Automatic tools were developed for the estimation of the 3-D positioning of the ICRS. The pupil center reference was estimated from the segmented iris volume. The developed algorithms are illustrated in a keratoconic eye (grade III) pre- and 30 days post-operatively after implantation of two triangular-section, 0.3-mm thick Ferrara ring segments. Quantitative corneal topographies reveal that the ICRS produced a flattening of the anterior surface, a steepening of the posterior surface, meridional differences in the changes in curvature and asphericity, and increased symmetry of the anterior topography. Optical distortion correction through the ICRS (of a different refractive index from the cornea) allowed accurate pachymetric estimates, which showed increased thickness in the ectatic area as well as in peripheral corneal areas. Automatic tools allowed estimation of the depth of the implanted ICRS ring, as well as its rotation with respect to the pupil plane. Anterior segment sOCT provided with fan and optical distortion correction and analysis tools is an excellent instrument for evaluating and monitoring keratoconic eyes and for the quantification of the changes produced by ICRS treatment.

[Quantifying and classifying postsurgical pain in pterygium surgery with conjunctival autografts]. / Cuantificación y cualificación del dolor postquirúrgico en la cirugía de pterigión con autoinjerto conjuntival.

OBJECTIVE: Quantify and define post-surgical pain after pterygium surgery with conjunctival autografts. MATERIAL AND METHODS: The study included 17 patients. The parameters analysed were, gender, age, pterygium TCL classification, primary characteristics or relapse, usage of isolated tissue adhesive or extra fixation with stitches. A visual analogue pain scale was used immediately after surgery, on the days 2 and 3 post-surgery, and the characteristics of the pain and the frequency of it in days 2 and 3 following the surgery. RESULTS: A total of 17 eyes of 17 patients were operated. The majority of patients (52.9%) showed moderate pain on the visual analogue scale immediately after surgery. On day 2 after surgery the pain level was mild in the majority of patients with characteristics of sharp pain and lash pain predominantly. On day 3 after surgery, mild pain was also predominant, with characteristics of stinging and lash pain in majority of patients. CONCLUSIONS: Using scales and pain characteristics we can quantify and define post-surgical pain after pterygium surgery with conjunctival auto-grafts resection immediately after surgery and in the following days.

Cuantificación y cualificación del dolor postquirúrgico en la cirugía de pterigión con autoinjerto conjuntival / Quantifying and classifying postsurgical pain in pterygium surgery with conjunctival autografts

ObjetivoCuantificar y definir el dolor postquirúrgico tras cirugía de pterigión mediante resección con autoinjerto conjuntival.Material y métodosEn el estudio se han incluido 17 pacientes. Los parámetros analizados han sido sexo, edad, clasificación TCL del pterigión, carácter primario o recidiva del mismo, uso de adhesivo tisular aislado o con fijación extra con puntos de sutura, escala visual analógica de dolor inmediato a la cirugía, en el día 2 y en el 3 postcirugía, al igual que las características del dolor e intervalo del mismo en los días 2 y 3 postcirugía.ResultadosSe intervinieron 17 ojos de 17 pacientes. En relación a los datos obtenidos en la escala analógica visual para el dolor, en los resultados inmediatos a la cirugía la mayor parte de los pacientes (52,9%) presentaron dolor moderado. En el día 2 postcirugía el nivel de dolor fue predominantemente leve, con características de pinchazo y latigazo de forma mayoritaria. En el día 3 postcirugía, de nuevo destacó el dolor de grado leve, con características de escozor y latigazo en mayor porcentaje.ConclusionesMediante la utilización de escalas de nivel y características de dolor podemos cuantificar y definir el dolor postquirúrgico tras cirugía de pterigión mediante resección con autoinjerto conjuntival en el postoperatorio inmediato y días sucesivos(AU)

ObjectiveQuantify and define post-surgical pain after pterygium surgery with conjunctival autografts.Material and methodsThe study included 17 patients. The parameters analysed were, gender, age, pterygium TCL classification, primary characteristics or relapse, usage of isolated tissue adhesive or extra fixation with stitches. A visual analogue pain scale was used immediately after surgery, on the days 2 and 3 post-surgery, and the characteristics of the pain and the frequency of it in days 2 and 3 following the surgery.ResultsA total of 17 eyes of 17 patients were operated. The majority of patients (52.9%) showed moderate pain on the visual analogue scale immediately after surgery. On day 2 after surgery the pain level was mild in the majority of patients with characteristics of sharp pain and lash pain predominantly. On day 3 after surgery, mild pain was also predominant, with characteristics of stinging and lash pain in majority of patients.ConclusionsUsing scales and pain characteristics we can quantify and define post-surgical pain after pterygium surgery with conjunctival auto-grafts resection immediately after surgery and in the following days(AU)

Balance of corneal horizontal coma by internal optics in eyes with intraocular artificial lenses: evidence of a passive mechanism.

It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma. It has been debated whether the compensation of horizontal coma is the result of passive mechanism [Artal, P., Benito, A., & Tabernero, J. (2006). The human eye is an example of robust optical design. Journal of Vision, 6 (1), 1-7] or through an active developmental feedback process [Kelly, J. E., Mihashi, T., & Howland, H. C. (2004). Compensation of corneal horizontal/vertical astigmatism, lateral coma, and spherical aberration by internal optics of the eye. Journal of Vision, 4 (4), 262-271]. In this study we investigate the active or passive nature of the horizontal coma compensation using eyes with artificial lenses, where no active developmental process can be present. We measured total and corneal aberrations, and lens tilt and decentration in a group of 38 eyes implanted with two types of intraocular lenses designed to compensate the corneal spherical aberration of the average population. We found that spherical aberration was compensated by 66%, and horizontal coma by 87% on average. The spherical aberration is not compensated at an individual level, but horizontal coma is compensated individually (coefficients of correlation corneal/internal aberration: -0.946, p<0.0001). The fact that corneal (but not total) horizontal coma is highly correlated with angle lamda (computed from the shift of the 1st Purkinje image from the pupil center, for foveal fixation) indicates that the compensation arises primarily from the geometrical configuration of the eye (which generates horizontal coma of opposite signs in the cornea and internal optics). The amount and direction of tilts and misalignments of the lens are comparable to those found in young eyes, and on average tend to compensate (rather than increase) horizontal coma. Computer simulations using customized model eyes and different designs of intraocular lenses show that, while not all designs produce a compensation of horizontal coma, a wide range of aspheric biconvex designs may produce comparable compensation to that found in young eyes with crystalline lenses, over a relatively large field of view. These findings suggest that the lens shape, gradient index or foveal location do not need to be fine-tuned to achieve a compensation of horizontal coma. Our results cannot exclude a fine-tuning for the orientation of the crystalline lens, since cataract surgery seems to preserve the position of the capsule.

Ultrasound biomicroscopy of ZSAL-4 anterior chamber phakic intraocular lens for high myopia.

PURPOSE: To evaluate the intraocular location and anatomic relationship to other structures of the ZSAL-4 angle-supported anterior chamber phakic intraocular lens (IOL) for high myopia using ultrasound biomicroscopy (UBM). SETTING: Clínica de Nuestra Señora de la Concepción, Fundación Jiménez Díaz, and Instituto de Investigaciones Oftalmológicas Ramón Castroviejo, Madrid, Spain. METHODS: Eight phakic myopic eyes corrected by ZSAL-4 angle-supported anterior chamber phakic IOLs were examined by UBM. The distance between the corneal endothelium and the IOL at the central and peripheral cornea and between the phakic IOL and the iris was measured. RESULTS: The mean distance between the central cornea and the IOL was 2361.37 microm +/- 109.62 (SD); between the edge of the IOL optic and the endothelium, 1646.24 +/- 27.06 microm; and between the IOL and the iris, 354.46 +/- 41.61 microm. The IOL footplates appeared to be correctly positioned in the anterior chamber angle in all eyes. CONCLUSION: The space between the IOL and the endothelium was greater in eyes with the ZSAL-4 angle-supported phakic IOL than in eyes with other angle-supported phakic IOLs. The possibility of intermittent contact between the IOL edge and the midperipheral cornea plays a minor role in the mechanism of endothelial damage with this lens model.

Therapeutic lamellar keratoplasty with an automated microkeratome.

Penetrating keratoplasty (PKP) is the predominant form of corneal transplantation because both manual and automated lamellar keratoplasty are technically difficult and lead to complications such as irregularities and scarring. A microkeratome for laser in situ keratomileusis can be used to overcome these disadvantages. We describe a technique of lamellar keratoplasty performed with an automated microkeratome to treat corneal opacities in the anterior third of the cornea. This easy, accurate technique leads to good visual results and represents a good alternative to PKP in treating anterior corneal opacities.

Safety of posterior chamber phakic intraocular lenses for the correction of high myopia: anterior segment changes after posterior chamber phakic intraocular lens implantation.

OBJECTIVE: To assess the safety of posterior chamber phakic intraocular lens (PCPIOL) implantation in patients with high myopia. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: Twenty eyes of 10 patients were included. INTERVENTION: Staar Collamer Implantable Contact Lens PCPIOLs were implanted for the correction of high myopia. MAIN OUTCOME MEASURES: Intra- and postoperative complications were recorded. Specular microscopy, lens fluorophotometry, laser flare-meter, and ultrasound biomicroscopy were performed before surgery and at different stages of the follow-up period to evaluate endothelial cell density, crystalline lens transmittance, aqueous flare, and anatomic relations of the implanted lenses with the other structures of the anterior segment. RESULTS: There were no intraoperative complications. One patient experienced pupillary entrapment by the lens in the immediate postoperative period, which was resolved without incident. Pigmentary dispersion or cataracts did not appear during the postoperative period. All the lenses remained correctly centered, and no patient reported night halos or glare. Anterior chamber depth showed a statistically significant reduction, between 9% and 12%. Central endothelial density was significantly decreased after surgery. The percentages of cell loss after 3, 6, 12, 18, and 24 months were 4.41%, 4.83%, 5.17%, 5.46%, and 6.57%, respectively. Aqueous flare increased by 49.19% in the first postoperative month in relation to preoperative values. Afterward, it decreased and then remained above preoperative values for the entire follow-up period (33.76% at month 3, 27.81% at month 6, 27.65% at month 12, 23.39% at month 18, and 27.27% at month 24). Crystalline lens transmittance decreased by 0.72% at month 3, by 1.44% at month 6, by 1.95% at month 12, by 2.25% at month 18, and by 2.24% at month 24. Finally, by ultrasound biomicroscopy it was observed that the PCPIOL and the crystalline lens were in contact on the peripheral level in 12 patients (60%) and in the center in another three patients (15%) during at least one checkup. In all the patients, contact between the PCPIOL and the posterior iris surface could be observed. CONCLUSIONS: Posterior chamber phakic IOL implantation for the surgical correction of high myopia is a safe procedure with regard to immediate visual and refractive results. The short-term clinical benefit and lack of immediate surgical complications are impressive. However, the increase in flare, the endothelial cell loss, the decrease in crystalline lens transmittance, and the iris-PCPIOL and crystalline lens-PCPIOL contact are findings that suggest caution regarding the long-term safety of this lens implant.

Contrast sensitivity after posterior chamber phakic intraocular lens implantation for high myopia.

PURPOSE: To evaluate contrast sensitivity after posterior chamber phakic intraocular lens (PIOL) implantation for the correction of high myopia. METHODS: Twenty eyes of ten patients had a posterior chamber phakic intraocular lens (Staar ICL) implanted to correct high myopia. Mean preoperative myopia was -14.10+/-2.70 D. Follow-up was 24 months for all patients. Contrast sensitivity was tested with best spectacle-corrected visual acuity preoperatively and 3, 6, 12, 18, and 24 months postoperatively. RESULTS: Contrast sensitivity increased after surgery in all spatial frequencies. Normal values were achieved for low and intermediate spatial frequencies (3 and 6 c/deg). However, in spite of the improvement, values were still below normal for high spatial frequencies (12 and 18 c/deg). When the first postoperative examination was not considered, there were no statistically significant differences in contrast sensitivity values at different postoperative periods. CONCLUSION: Contrast sensitivity increased after posterior chamber phakic intraocular lens implantation (Staar ICL) in all spatial frequencies when compared to preoperative contrast sensitivity (best spectacle-corrected).

Surgical correction of severe myopia with an angle-supported phakic intraocular lens.

PURPOSE: To evaluate the effectiveness, predictability, and safety of a fourth-generation angle-supported anterior chamber phakic intraocular lens (IOL) in patients with severe myopia. SETTING: Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology, Miguel Hernández University School of Medicine, Alicante, Spain. METHODS: In this prospective study, 23 eyes (16 patients) with a mean preoperative myopia of -19.56 diopters (D) +/- 1.76 (SD) (range -16.75 to -23.25 D) were implanted with the ZSAL-4 phakic IOL. Basic examinations were performed before and after surgery in all patients. Eighteen eyes were also studied by clinical specular microscopy, and the endothelium was analyzed for cell density, coefficient of variation in cell size, and hexagonality. The location of the IOL in the anterior chamber was evaluated in 10 eyes by A-scan biometry. To evaluate haptic geometry, a theoretical mechanical model was used. The follow-up was 24 months in all patients. RESULTS: Uncorrected visual acuity was 20/40 or better in 13 eyes (56.0%) 12 months after surgery and in 14 eyes (60.8%) at 24 months. Best spectacle-corrected visual acuity improved 0.19 at 12 and 24 months (0.1 = 1 line) from preoperative values. The efficacy index was 1.12 at 24 months and the safety index, 1.45. The mean postoperative spherical equivalent was -0.65 +/- 0.65 D at 24 months. The postoperative spherical equivalent was within +/-1.00 D of emmetropia in 19 eyes (82.6%) at 12 and 24 months. The mean endothelial cell loss was 3.50% at 12 months and 4.18% at 24 months. The coefficient of variation in cell size decreased from 0.34 before surgery to 0.28 at 24 months after surgery. The IOL was located 0.79 +/- 0.24 mm in front of the crystalline lens. Postoperative complications included night halos in 6 eyes (26.1%) at 12 and 24 months and pupil ovalization in 4 eyes (17.4%). Intraocular lens rotation was observed in 10 eyes (43.5%) at 24 months. Two eyes (8. 7%) developed a slight inflammatory response during the first 6 months. Our mechanical model predicted that the compression forces against the angle structures were greater at the first footplate than at the second. CONCLUSIONS: Implantation of the ZSAL-4 IOL in the anterior chamber of phakic eyes was effective and predictable in correcting severe myopia. However, the ZSAL-4 did not prevent pupil ovalization, IOL rotation, or low-grade postoperative uveitis. Improvements in haptic design following our mechanical model could decrease these haptic-related complications.

Clear lens extraction and implantation of negative-power posterior chamber intraocular lenses to correct extreme myopia.

PURPOSE: To evaluate the effectiveness, predictability, and safety of clear lens extraction to correct extreme myopia. SETTING: Clinica de Nuestra Señora de la Concepción, Fundación Jiménez Díaz, Madrid, Spain. METHODS: This retrospective study comprised 26 eyes of 17 highly myopic patients who had clear lens extraction and implantation of a negative-power posterior chamber intraocular lens (IOL). The IOL power was calculated using the SRK/T formula. Analyzed were visual and refractive results and intraoperative and postoperative complications. Follow-up was at least 12 months in all cases. RESULTS: Uncorrected visual acuity improved in all cases, with 80.77% of eyes achieving 20/100 or better and 42.30%, 20/40 or better. Best spectacle-corrected visual acuity (BSCVA) improved in 23 eyes (88.46%). The percentage of eyes achieving a BSCVA of 20/100 or better increased from 73.07% preoperatively to 92.30% postoperatively and the percentage achieving 20/40 or better, from 23.07 to 73.07%. Of the 26 eyes, 76.91% were within 1.00 diopter (D) of refractive error and 96.16% were within 2.00 D. No intraoperative complications occurred. Although postoperatively 3 eyes (11.53%) developed choroidal detachment and 5 (19.23%) had an intraocular pressure greater than 25 mm Hg, all had a favorable outcome. Four eyes (15.38%) developed posterior capsule opacification and had a neodymium:YAG laser posterior capsulotomy 6 months postoperatively. No retinal detachments were observed. CONCLUSION: Clear lens extraction with negative-power IOL implantation using the SRK/T formula had good effectiveness, acceptable predictability, and a low morbidity in eyes with extreme myopia over a short follow-up. A longer follow-up with more cases is needed to assess the safety of the procedure.

Pupil response to tropicamide in Alzheimer's disease and other neurodegenerative disorders.

Excessive mydriatic response to dilute tropicamide has been suggested as a possible non-invasive diagnostic test in patients with Alzheimer's disease (AD). To further evaluate the sensibility and specificity of this test we studied the pupillary response to tropicamide in 24 patients with AD, 30 age-matched controls, 7 patients with dementia other than AD and 13 patients with extrapyramidal disorders (EXD). Maximum dilatation response over baseline was much higher in AD with significant differences compared to controls (p < 0.001) and to EXD (p < 0.05). However, there was a quite wide range of overlap between AD and controls and no cut-off point was found with a high enough specificity to consider this a conclusive diagnostic test. Lower dilatation response in the overlapping range (13%), however, may be useful because of its negative predictive value (93.5%) and as a screening tool due to its sensitivity (87.5%).

Photorefractive keratectomy for myopic astigmatism using the emphasis erodible mask. Spanish User Group.

Photorefractive keratectomy (PRK) using the Summit emphasis erodible mask was performed on 229 eyes with myopic astigmatism. To analyze the efficacy and safety of the method, we evaluated the following: spectacle corrected visual acuity and refractive error as parameters of efficacy; corneal clarity, decentration of the ablation zone and complications as parameters of safety. Despite the short follow up (the longest was 12 months) our results show that the emphasis erodible mask appears to be an effective surgical method for correcting myopic astigmatism. However, we found a great number of complications and subjective symptoms that worsened the visual outcome. We conclude that the emphasis erodible mask has satisfactory efficacy but unsatisfactory safety.

Corneal endothelial permeability after implantation of angle-fitted anterior chamber lenses in myopic phakic eyes. Preliminary results.

This present study aimed to evaluate the corneal endothelium after implantation of angle-fixed anterior chamber lenses in myopic phakic eyes. Twelve eyes (9 patients) with high myopia (more than-14 diopters) were implanted with ZB5M lenses (Domilens, France). The corneal endothelium was studied by fluorophotometry (endothelial transfer coefficient: kc.ca), specular microscopy and ultrasonic pachimetry. Tests were performed prior to and 3 and 6 months after the surgery. The Wilcoxon rank test was used for the statistical analysis of the data. There was a significant difference (p < 0.05) between the preoperative kc.ca (4.15 +/- 0.72 x 10(-3) min-1) and the kc.ca three months after the implantation (4.43 +/- 0.87 x 10(-3) min-1). A statistically significant difference (p < 0.01) was also found between the three and six months postoperative kc.ca (5.31 +/- 0.81 x 10(-3) min-1). There was a significant difference (p < 0.05) between the preoperative central endothelial cell density (2533 +/- 219 cells/mm2). No significant differences were found in relation to the central corneal thickness. In conclusion, three months after the implantation of ZB5M lenses to correct high myopia in phakic eyes, the corneal endothelial function was altered and continued to be so six months after the operation.

Effect of bendazac lysine on lens and retina in diabetics.

The possible beneficial effects on the lens and retina which Bendazac Lysine may have in the treatment of adult diabetic patients were investigated. Twenty patients, ranging in age from 54.80 +/- 5.86 years old, were studied. The average duration of the diabetes was 11.32 +/- 4.10 years. Thirteen patients had background retinopathy. The metabolic controls carried out during the study were satisfactory (HbA1 < 11%). Bendazac Lysine (500 mg three times a day) was administered for 6 months. Blood-retinal barrier permeability (VPR and VPRt) and lens transmittance (t) were evaluated prior to and 6 months after treatment by fluorophotometry. No statistically significant differences between the pre- and post-treatment values of the retina permeability were observed, however, there was a statistically significant improvement (p < 0.05) (initial value: t = 0.813 +/- 0.040 and final value: t = 0.823 +/- 0.037) in the lens transmittance. The authors conclude that Bendazac Lysine has a beneficial effect on the lens in the diabetic adult although no improvement in the permeability of the blood-retinal barrier has been observed.