Rafael I. Barraquer

Corneal biomechanics, refraction, and corneal aberrometry in keratoconus: an integrated study.

Purpose. To evaluate the relationship of corneal biomechanical properties to refraction and corneal aberrometry in keratoconic eyes. Methods. A total of 81 consecutive keratoconic eyes of 81 patients ranging in age from 11 to 58 years were included in the study. Three groups were differentiated according to the severity of keratoconus: mild (37 eyes), moderate (24 eyes), and severe (20 eyes). Visual acuity, refraction, corneal topography, and corneal aberrations were evaluated. In addition, corneal biomechanics were analyzed in relation to two parameters: corneal hysteresis (CH) and corneal resistance factor (CRF). Correlations between these biomechanical factors and the remaining clinical parameters were investigated. Results. CH and CRF in the severe keratoconus group were significantly lower than those in the other two groups (P < or = 0.01). A significant difference in CRF was found between mild and moderate cases (P = 0.04). A moderate correlation was found between the CRF and mean keratometry in the overall sample (r = -0.564). In addition, a significant, strong correlation was found between the spherical-like root mean square (RMS) and the CRF only in the severe keratoconus group (r = -0.655). Multiple regression analysis revealed that CRF correlated significantly with keratometry and the corneal spherical-like RMS (R(2) = 0.40, P < 0.01). Conclusions. The CRF correlates with the magnitude of corneal spherical-like aberrations, especially in severe keratoconus. It should be considered an additional factor in keratoconus grading.

Keratoconus-integrated characterization considering anterior corneal aberrations, internal astigmatism, and corneal biomechanics

PURPOSE: To evaluate the clinical features of keratoconus taking into consideration anterior corneal aberrations, internal astigmatism, and corneal biomechanical properties and to define a new grading system based on visual limitation. SETTING: Vissum Corporation, Alicante, Spain. DESIGN: Retrospective case series. METHODS: This multicenter study comprised consecutive keratoconic eyes with no previous ocular surgery or active ocular disease. Visual, refractive, corneal topography, and pachymetry outcomes were analyzed. Internal astigmatism was calculated by vectorial analysis. Corneal aberrations and corneal biomechanics characterized by the Ocular Response Analyzer were evaluated in some eyes. Correlations between clinical data and a linear multiple regression analysis for characterizing the relationship between visual limitation and objective clinical data were performed. RESULTS: This study comprised 776 eyes of 507 patients (age range 11 to 79 years) The mean keratometry (K) correlated significantly with logMAR corrected distance visual acuity (CDVA) (r = 0.591, P<.01), internal astigmatism (r = 0.497, P<.01), corneal asphericity (r = −0.647, P<.01), and several corneal higher‐order aberrometric coefficients (r≥0.603, P<.01). Significant correlations were found between some corneal aberrometric parameters and CDVA (r≥0.444, P<.01). Multiple regression analysis showed that CDVA was significantly correlated with the mean K, intraocular pressure, corneal resistance factor, and spherical equivalent (r2 = 0.69, P<.01). There were significant differences in mean K, internal astigmatism, and corneal higher‐order aberrations between 4 groups differentiated by visual limitation (P<.01). CONCLUSION: The visual limitation in keratoconus could be explained by different alterations that occur in these corneas and allowed development of a new grading system for this condition. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Air-pulse corneal applanation signal curve parameters for the characterisation of keratoconus

Aims To test the use of parameters obtained from the ocular response analyser (ORA) to distinguish between normal and keratoconic eyes, to determine the severity of keratoconus (KC), and to evaluate changes after treatment with cross-linking (CXL) and intrastromal corneal ring (ICR) implantation. Methods In total, 42 parameters were derived from the ORAs applanation response curve. Data on 119 subjects were included in the study. We determined the power of discrimination between control subjects (n=48) and KC patients (stages I and II, n=54) using receiver operating characteristic (ROC) curves. We then tested the correlation between all KC stages (n=71) and the ORA parameters. Finally, we evaluated the changes at 4 months after CXL (n=22) and ICR (n=39). Results The ROC curves for 12 parameters showed excellent results; 24 parameters generated moderate results and six parameters generated poor results. The correlations between the KC stages and 14 parameters were significant, with good to moderate results. The corneal resistance factor and the area under the second peak of the signal curve produced the best results in distinguishing between normal and KC eyes. Two parameters after CXL (p2area and time1) and six parameters after ICR implantation (aplhf, uslope11, w11, path11, time1 and deltatime) showed significant differences with respect to the preoperative conditions. Conclusion Most of the new waveform parameters demonstrated good ability to distinguish between KC and normal eyes. The changes in the parameter values after CXL and ICR treatments were smaller than expected.

Association of lens opacities, intraocular straylight, contrast sensitivity and visual acuity in European drivers

Purpose:  To study the relationship between lens opacity and intraocular straylight, visual acuity and contrast sensitivity.

Late in-the-bag intraocular lens dislocation requiring explantation: risk factors and outcomes

PurposeTo study the predisposing factors for late in-the-bag intraocular lens (IOL) dislocation and to analyze the outcomes after explantation surgery.MethodsIn this retrospective multicentre study, 61 eyes were enrolled. The main inclusion criterion was in-the-bag spontaneous IOL dislocation after uneventful phacoemulsification cataract extraction. Only eyes with serious dislocation that required IOL explantation were eligible. Follow-up after explantation surgery of at least 3 months was required. Exclusion criteria were complicated cataract surgery, out-of-the-bag IOL dislocation, and dislocations that occurred in the first year after the cataract surgery. The main outcome measures were predisposing factors for dislocation, interval between cataract surgery and dislocation, surgical treatment at the time of explantation, preoperative and postoperative corrected distance visual acuity (CDVA), and postoperative complications.ResultsHigh myopia was detected in 12 cases (19.7%) and it was the main predisposing factor. Mean time interval from cataract surgery to dislocation was 7.5 (SD 5.2) years. The dislocated in-the-bag IOL was replaced with a scleral fixated IOL (36.1%), angle-supported anterior chamber IOL (31.1%), sulcus repositioning (18%), or posterior chamber iris sutured IOL (4.9%). Finally, 9.8% of the patients were left aphakic. Mean CDVA improved significantly after surgery (P=0.005). Final CDVA of 20/40 or better was achieved in 29 cases (47.5%).ConclusionsHigh myopia was the main risk factor for late in-the-bag IOL dislocation. Surgical treatment significantly improved the CDVA in our sample and was associated with a low complication rate.

Outcome Analysis of Intracorneal Ring Segments for the Treatment of Keratoconus Based on Visual, Refractive, and Aberrometric Impairment

PURPOSE To analyze the outcomes of intracorneal ring segment (ICRS) implantation for the treatment of keratoconus based on preoperative visual impairment. DESIGN Multicenter, retrospective, nonrandomized study. METHODS A total of 611 eyes of 361 keratoconic patients were evaluated. Subjects were classified according to their preoperative corrected distance visual acuity (CDVA) into 5 different groups: grade I, CDVA of 0.90 or better; grade II, CDVA equal to or better than 0.60 and worse than 0.90; grade III, CDVA equal to or better than 0.40 and worse than 0.60; grade IV, CDVA equal to or better than 0.20 and worse than 0.40; and grade plus, CDVA worse than 0.20. Success and failure indices were defined based on visual, refractive, corneal topographic, and aberrometric data and evaluated in each group 6 months after ICRS implantation. RESULTS Significant improvement after the procedure was observed regarding uncorrected distance visual acuity in all grades (P < .05). CDVA significantly decreased in grade I (P < .01) but significantly increased in all other grades (P < .05). A total of 37.9% of patients with preoperative CDVA 0.6 or better gained 1 or more lines of CDVA, whereas 82.8% of patients with preoperative CDVA 0.4 or worse gained 1 or more lines of CDVA (P < .01). Spherical equivalent and keratometry readings showed a significant reduction in all grades (P ≤ .02). Corneal higher-order aberrations did not change after the procedure (P ≥ .05). CONCLUSIONS Based on preoperative visual impairment, ICRS implantation provides significantly better results in patients with a severe form of the disease. A notable loss of CDVA lines can be expected in patients with a milder form of keratoconus.

Impact of Clinical Factors on the Long-Term Functional and Anatomic Outcomes of Osteo-odonto-keratoprosthesis and Tibial Bone Keratoprosthesis

PURPOSE To report the long-term functional and anatomic outcomes of osteo-odonto-keratoprosthesis and tibial bone keratoprosthesis; to analyze the influence of clinical factors, such as surgical technique, primary diagnosis, age, and postoperative complications, on the final outcome. DESIGN Retrospective cohort study. METHODS setting: Centro de Oftalmología Barraquer, between 1974 and 2005. PARTICIPANTS Two hundred twenty-seven patients. intervention: Biological keratoprosthesis using osteo-odonto-keratoprosthesis or tibial bone keratoprosthesis. main outcome measures: Functional survival with success defined as best-corrected visual acuity ≥0.05; anatomic survival with success defined as retention of the keratoprosthesis lamina. RESULTS Osteo-odonto-keratoprosthesis and tibial bone keratoprosthesis have comparable anatomic survival at 5 and 10 years of follow-up, but osteo-odonto-keratoprosthesis has a significantly better functional success than tibial bone keratoprosthesis at the same time periods. Among the primary diagnoses, Stevens-Johnson syndrome, chemical burn, and trachoma have generally good functional and anatomic outcomes and the least favorable prognosis is for ocular cicatricial pemphigoid. Younger patients fared better than those in older age groups. The most frequent complications were extrusion (28%), retinal detachment (16%), and uncontrolled glaucoma (11%). The glaucoma group had the best anatomic success but the worst functional results, only exceeded by the retinal detachment group in terms of functional outcome. CONCLUSION Clinical factors, such as surgical technique, primary diagnosis, age, and postoperative complications, can affect the long-term anatomic and functional successes of biological keratoprosthesis. Knowledge about the impact of each of these factors on survival can help surgeons determine the best approach in every particular case.

Modeling the Intracorneal Ring Segment Effect in Keratoconus Using Refractive, Keratometric, and Corneal Aberrometric Data

PURPOSE To characterize the refractive, keratometric, and corneal aberrometric effect of a specific type of intracorneal ring segment (ICRS) as a function of its thickness and the preoperative conditions of the cornea. METHODS A total of 72 consecutive keratoconic eyes of 57 patients ranging in age from 15 to 68 years were retrospectively analyzed and included in the study. All cases had a diagnosis of keratoconus and had undergone implantation of a 160° arc-length KeraRing segment (Mediphacos, Belo Horizonte, Brazil), by femtosecond laser technology. Correlations between ring segment thickness and several clinical parameters were investigated. In addition, a multiple regression analysis was performed to characterize all factors that influence the ring segment effect. RESULTS Significant reductions in central curvature, corneal astigmatism, and comalike aberrations were found after surgery (P ≤ 0.03). Moderate and limited correlations were found between ring segment thicknesses and changes in mean keratometry and higher order aberrations (r ≤ 0.50, P < 0.01). A consistent linear relationship of the superior ring segment thickness to the induced corneal changes, the preoperative cylinder, and the difference in thickness between inferior and superior segments was found (P < 0.01, R(2) = 0.91). An almost identical model was obtained for the inferior ring segment thickness with the only distinction in the factor being the thickness difference between segments (P < 0.01, R(2) = 0.64). CONCLUSIONS The selection of the ring segment to implant in keratoconus should be based, not only on refraction and subjective appearance of the corneal topographic pattern but also on corneal aberrometry. This highly customized selection would allow a more predictable outcome.

Corneal Biomechanical Changes After Intracorneal Ring Segment Implantation in Keratoconus

Purpose: To evaluate by means of the Ocular Response Analyzer (ORA) the biomechanical changes that follow intracorneal ring segment (ICRS) implantation and to develop a predicting model for the postoperative visual outcome, considering these biomechanical changes and other clinical parameters. Methods: A total of 45 consecutive keratoconic eyes of 35 patients aged 18 to 55 years and implanted with ICRS were included in this retrospective study. All patients were implanted with KeraRing using femtosecond laser technology. Visual acuity, refraction, corneal topography, and aberrations were evaluated during a 6-month follow-up. Additionally, corneal biomechanical changes were evaluated with the ORA system. Results: No significant changes in corneal hysteresis (CH) and corneal resistance factor (CRF) were observed at 1 month postoperatively (P ≥ 0.39). However, significant changes in these parameters were detected afterward (CH, 3 months, P = 0.03; CRF, 6 months, P = 0.02). Preoperative corneal biomechanical parameters were significantly correlated with postoperative corneal higher-order aberrations at all visits (P ⩽ 0.05), although these correlations became stronger at the end of the follow-up. Multiple regression analysis revealed that corrected distance visual acuity at 1 month after surgery was significantly correlated with the preoperative mean keratometry and the preoperative difference between CH and CRF (P < 0.01, adjusted R2 of 0.66). Conclusions: Biomechanical parameters measured with the ORA and mean keratometry are factors allowing a prediction of the postoperative visual outcome in a short term after ICRS implantation in keratoconic eyes. In the long term, corneal biomechanical changes limit the prediction of the ring segment effect.

Fungal Infection in Patients with Serpiginous Choroiditis or Acute Zonal Occult Outer Retinopathy

ABSTRACT The etiologies of a number of retinopathies, including serpiginous choroiditis and acute zonal occult outer retinopathy (AZOOR), remain uncertain. Recently, we provided evidence that AZOOR is caused by Candida famata infection. The purpose of this article was to investigate the presence of fungal infection in five patients affected with serpiginous choroiditis and five patients with diagnosis of AZOOR. To assess the presence of fungal infection the presence of antibodies in human serum samples against C. famata, C. albicans, C. parapsilosis, C. glabrata and C. krusei was analyzed. In addition, quantitative PCR was carried out to detect fungal genomes in whole blood. Finally, the presence of fungal antigens in the serum samples of patients was investigated. Three AZOOR patients presented high antibody titers against Candida spp., while antibodies against Candida spp. were observed in serum samples from four patients with serpiginous choroiditis. Fungal genomes in peripheral blood were evidenced in serum samples from one AZOOR and four serpiginous choroiditis patients. Fungal antigens were also apparent in the serum of different patients. Our findings indicate that there was evidence of disseminated fungal infection in most patients examined.