Javier Moreno-Montañés

Optical coherence tomography evaluation of the corneal cap and stromal bed features after laser in situ keratomileusis for high myopia and astigmatism

OBJECTIVE To study the corneal microstructure by optical coherence tomography (OCT) after laser in situ keratomileusis (LASIK) for high myopia with and without astigmatism. DESIGN Nonrandomized self-controlled comparative trial. PARTICIPANTS Sixty-three consecutive LASIK eyes with spherical equivalent refraction between -6.0 and -17.0 diopters (D) and astigmatism between 0.0 and -5.0 D were prospectively recruited for examination. INTERVENTION LASIK was performed with the Chiron Hansatome microkeratome (160-microm fixed plate) and Summit Apex Plus excimer laser using a 5.5/6.0/6.5-mm multizone pattern. Proper preoperative calculations were performed to ensure stromal beds thicker than 250 microm. MAIN OUTCOME MEASURES OCT imaging and measurement of corneal thickness was performed preoperatively. In addition, corneal cap and stromal bed thickness measurements were performed 1 day, 1 month, and 3 months postoperatively. RESULTS The average central corneal pachymetry was 538.9 +/- 26.2 microm preoperatively. Mean corneal cap thickness measured 124.8 +/- 18.5 microm 1-day postoperatively. Mean stromal bed thickness was 295.2 +/- 37.1 microm on the first postoperative day. Compared with the 1-day postoperative examination, the average stromal bed thickness increased significantly by 5.9 microm (P = 0.001) and 7.2 microm (P = 0.001) at the 1-month and 3-month postoperative examinations, respectively. Mean difference between actual (118.7 +/- 27.8 microm) and predicted (104.1 +/- 20.8 microm) central ablation depths was 14.6 +/- 16.7 microm (P = 0.0001). A weak but statistically significant positive association was found between preoperative refraction and the difference between expected and real ablation depth values (R = 0.26; P = 0.042). Posterior stromal beds were more than 250-microm thick in 58 eyes (89.9%) 1 day postoperatively. This safety requirement improved at the 1-month postoperative examination, when the partial regression accounted for slightly thicker stromal beds and only two cases (3.2%) exhibited posterior stromal tissue thinner than 250 microm. These two cases were seen only for corrections exceeding 12 D (P = 0.04). CONCLUSIONS OCT appears to be a useful tool for the evaluation of both the qualitative and quantitative anatomic outcome of LASIK. Corrections of higher degrees of ametropia run a higher risk of producing a thinner than expected central cornea. Particularly, corrections greater than 12 D may lead eventually to stromal beds thinner than 250 microm, despite proper preoperative calculations. Because corneal flaps are usually thinner than expected with the microkeratome used herein, adequate posterior corneal stroma is preserved in most instances.

Reproducibility and Clinical Relevance of the Ocular Response Analyzer in Nonoperated Eyes: Corneal Biomechanical and Tonometric Implications

PURPOSE To assess the reproducibility of the ocular response analyzer (ORA) in nonoperated eyes and the impact of corneal biomechanical properties on intraocular pressure (IOP) measurements in normal and glaucomatous eyes. METHODS In the reliability study, two independent examiners obtained repeated ORA measurements in 30 eyes. In the clinical study, the examiners analyzed ORA and IOP-Goldmann values from 220 normal and 42 glaucomatous eyes. In both studies, Goldmann-correlated IOP measurement (IOP-ORAg), corneal-compensated IOP (IOP-ORAc), corneal hysteresis (CH), and corneal resistance factor (CRF) were evaluated. IOP differences of 3 mm Hg or greater between the IOP-ORAc and IOP-ORAg were considered outcome significant. RESULTS Intraexaminer intraclass correlation coefficients and interexaminer concordance correlation coefficients ranged from 0.78 to 0.93 and from 0.81 to 0.93, respectively, for all parameters. CH reproducibility was highest, and the IOP-ORAg readings were lowest. The median IOP was 16 mm Hg with the Goldmann tonometer, 14.5 mm Hg with IOP-ORAg (P < 0.001), and 15.7 mm Hg with IOP-ORAc (P < 0.001). Outcome-significant results were found in 77 eyes (29.38%). The IOP-ORAc, CH, and CRF were correlated with age (r = 0.22, P = 0.001; r = -0.23, P = 0.001; r = -0.14, P = 0.02, respectively), but not the IOP-ORAg or IOP-Goldmann. CONCLUSIONS The ORA provides reproducible corneal biomechanical and IOP measurements in nonoperated eyes. Considering the effect of ORA, corneal biomechanical metrics produces an outcome-significant IOP adjustment in at least one quarter of glaucomatous and normal eyes undergoing noncontact tonometry. Corneal viscoelasticity (CH) and resistance (CRF) appear to decrease minimally with increasing age in healthy adults.

Cirrus High-Definition Optical Coherence Tomography Compared with Stratus Optical Coherence Tomography in Glaucoma Diagnosis

PURPOSE To compare the retinal nerve fiber layer (RNFL) evaluation using Cirrus optical coherence tomography (OCT) and Stratus OCT in glaucoma diagnosis. METHODS One hundred thirty normal and 86 patients with glaucoma were included in this prospective study. The signal strengths of the OCTs were evaluated. The sensitivities and specificities of global RNFL average thickness were compared in the four quadrants and in each clock hour sector. Receiver operating characteristic (ROC) curves, areas under the ROC (AUC), and the likelihood ratio (LR) were plotted for RNFL thickness. Agreement between the OCTs was calculated by using the Bland-Altman method and kappa (kappa) coefficient. RESULTS Twenty-three percent of all cases examined with Stratus OCT and 1.9% examined with Cirrus OCT had a signal strength below 6 (P = 0.01). In cases with signal strengths > or =6, the mean signal strength was higher with Cirrus OCT than with Stratus OCT (P = 0.01). The RNFL measurements by Cirrus were thicker than those of Stratus OCT (P < 0.05). The AUCs were 0.829 for Stratus and 0.837 for Cirrus OCT (P = 0.706) for global RNFL average. LRs were similar in both OCTs in global RNFL classification but varied in quadrants. The widths of the limits of agreement varied between 42.16 and 97.79 microm. There was almost perfect agreement (kappa = 0.82) in the average RNFL classification. CONCLUSIONS Cirrus OCT has better scan quality than Stratus OCT, especially in glaucomatous eyes. In cases with good-quality scans, the sensitivity and specificity, and AUCs were similar. The best agreement was in the global average RNFL classification. The widths of limits of agreements exceed the limits of resolution of the OCTs.

Usefulness of optical coherence tomography parameters of the optic disc and the retinal nerve fiber layer to differentiate glaucomatous, ocular hypertensive, and normal eyes.

PurposeTo assess Stratus optical coherence tomography (OCT) original parameters for identifying glaucomatous damage and to evaluate differences among glaucomatous, ocular hypertensive, and normal eyes. DesignCross-sectional prospective study. Subjects and MethodsThe study was conducted at 2 centers. The study population consisted of 55 normal individuals, 95 patients with ocular hypertension (OHT), and 79 patients with glaucoma. Retinal nerve fiber layer (RNFL) and optic nerve head OCT protocols were used to evaluate all study participants. Measurements taken were RNFL thickness, several ratios, RNFL asymmetry between both eyes, rim volume, rim width, disc area, cup area, rim area, cup/disc (C/D) area ratio, and horizontal and vertical C/D ratios. The main outcome measures were the differences in OCT parameters among groups and the areas under the receiver operating characteristic curves (AROC). ResultsMean RNFL thickness around the disc, and superior and inferior RNFL thickness, were significantly thinner in glaucomatous eyes than in OHT or normal eyes (P<0.001). Rim parameters were significantly smaller in glaucomatous eyes than in normal (P<0.001) and OHT eyes (P=0.01). C/D ratios were significantly greater in glaucomatous eyes than in OHT (P<0.001) and normal (P<0.001) eyes. Significant differences were found between normal and OHT eyes in 7 disc parameters. No difference was found among groups in parameters describing RNFL asymmetry between both eyes. The AROC curves of the other RNFL and disk parameters ranged from 0.741 to 0.85. ConclusionsAlmost all RNFL and disc parameters showed significant differences and discriminated between glaucomatous and normal eyes. There were significant differences in some optic nerve parameters, but no RNFL parameters, between normal and OHT eyes.

Clinical factors related to the frequency and intensity of glistenings in AcrySof intraocular lenses

Purpose: To assess the frequency of glistenings in eyes that had phacoemulsification and implantation of AcrySof intraocular lenses (IOLs) (Alcon) and to evaluate the clinical factors related to the glistenings. Setting: Departamento de Oftalmología, Clínica Universitaria, Universidad de Navarra, Pamplona, Spain. Methods: A consecutive series of 129 eyes of 94 patients was prospectively evaluated. All patients had cataract surgery and implantation of an MA30BA AcrySof IOL by the same surgeon using the same technique. The operating surgeon examined patients for the presence of glistenings. The frequency and intensity of glistenings were assessed in relation to 14 clinical factors. The effect of glistenings on postoperative Snellen best corrected visual acuity (BCVA) was also evaluated. Results: Glistenings, which occurred in 38 cases (29.5%), were slight in 15 eyes, moderate in 18, and intense in 5. The frequency of the glistenings was related to the time between surgery and evaluation (P = .0001), the IOL dioptric power (P = .01), postoperative inflammation (P = .01), and phacotrabeculectomy (P = .01). The intensity of the glistenings was related to the time after surgery (P = .01) and presence of postoperative inflammation (P = .004). No relation between glistenings and Snellen BCVA was found. Conclusions: The frequency and intensity of glistenings in AcrySof IOLs increased with time after surgery and were higher when postoperative inflammation was present. Glistenings developed more frequently in cases of phacotrabeculectomy but not after combined phacoemulsification and deep sclerectomy. Glistenings did not result in decreased Snellen BCVA.

Complete anterior capsule contraction after phacoemulsification with acrylic intraocular lens and endocapsular ring implantation

A 69-year-old man with pseudoexfoliation syndrome and bilateral cataract had phacoemulsification with continuous curvilinear capsulorhexis and implantation of a morcher endocapsular ring and AcrySof acrylic intraocular lens (IOL) (Alcon). Two months later, the patient had vision loss in the left eye with a visual acuity of 20/500. He presented with anterior capsule fibrosis in both eyes, with complete occlusion of the capsule opening in the left eye and mild occlusion in the right eye. After a neodymium:YAG laser anterior capsulotomy in the left eye, visual acuity was 20/20. This case shows that endocapsular ring implantation does not prevent anterior capsule contraction syndrome but can prevent IOL decentration.

Phase I clinical trial of SYL040012, a small interfering RNA targeting β-adrenergic receptor 2, for lowering intraocular pressure.

The objective of this study was to evaluate ocular tolerance, safety, and effect on intraocular pressure (IOP) of a topically administered small interfering RNA; SYL040012, on healthy volunteers. The study was an open-label, controlled, single-center study comprised of two intervals that enrolled 30 healthy subjects having IOP below 21 mmHg. SYL040012 was administered to one eye as a single dose to six subjects during interval 1. During interval 2 two different doses of SYL040012 were administered to one eye on a daily basis to two separate groups of 12 subjects each, over a period of 7 days. The contralateral eye was evaluated but not administered and served as control for the tolerance study. SYL040012 was well tolerated locally. No local or systemic adverse events related to the product developed in response to any of the doses studied. SYL040012 was not detected in plasma at any time point. Administration of SYL040012 over a period of 7 days reduced IOP values in 15 out of 24 healthy subjects regardless of the dose used. IOP decrease was statistically significant in response to one of the doses tested and responsiveness to SYL040012 seemed to be greater in individuals with higher baseline IOP.

Comparison of retinal nerve fiber layer thickness values using Stratus Optical Coherence Tomography and Heidelberg Retina Tomograph-III.

PurposeTo evaluate the usefulness of retinal nerve fiber layer (RNFL) thickness measurements using the Heidelberg Retina Tomograph-III (HRT-III) in normal, ocular hypertensive, and glaucomatous eyes and compare the thickness measurements using HRT-III and Stratus Optical Coherence Tomography-3 (OCT-3). MethodsSixty-nine normal eyes, 60 eyes ocular hypertensive, and 111 glaucomatous were included. All participants underwent visual field, HRT-III, and OCT-3 examinations on the same day. Patients were classified into 3 groups according to intraocular pressure and visual field damage. The sensitivity/specificity of RNFL thickness measurements and RNFL thickness classifications using HRT-III and OCT-3 were calculated. The sensitivity/specificity of the height variation contour (HVC) from the HRT-III were calculated. The receiver operating characteristic curves (ROC) and areas under the ROC were plotted. Agreement was calculated using Bland-Altman method and the κ coefficient. ResultsThe RNFL thickness sensitivity/specificity were 32.4%/87%, for the HRT-III and 72.97%/81.15% for the OCT-3 in relation to the glaucoma diagnosis (least specific criteria). The RNFL thickness sensitivities/specificities were lower in early glaucoma. The areas under the ROC for RNFL measurements were 0.72 using HRT-III, 0.86 with OCT-3 (P=0.001), and 0.54 for the HVC. The RNFL classification κ coefficient was 0.36. Bland-Altman analysis confirmed that the RNFL measurements were not interchangeable. ConclusionsThe sensitivity of RNFL damage detection using HRT-III was lower compared with OCT-3, especially in early glaucoma. RNFL thickness agreement between HRT-III and OCT-3 was only fair. HVC was not useful for glaucoma detection.

Rebound tonometer compared with goldmann tonometer in normal and pathologic corneas.

Purpose: To compare the intraocular pressure (IOP) measurements obtained with the rebound tonometer (RT) and the Goldmann handheld tonometer (GT) in normal and altered corneas. Methods: A total of 208 normal corneas and 50 corneas with pathologies were included in this prospective study. All measurements were randomly obtained by 1 observer. The medians and interquartile range (IR) for both tonometers were compared. The median differences were assessed in IOP groups. Agreement between the tonometers was calculated using the Bland-Altman method. Results: The median IOP in all eyes was 17 mm Hg (IR, 13-22 mm Hg) with the RT and 16 mm Hg (IR, 13-21 mm Hg) with the GT (P < 0.001). The correlation was excellent between tonometers (r2 = 0.86; P < 0.001). The minimal differences between the two were obtained from 10 to 20 mm Hg (GT). The Bland-Altman scatterplot obtained good agreement between the instruments. In normal corneas, the median difference was ≤2 mm Hg in 77.4% of cases. In the altered corneas, the median difference was ≤2 mm Hg in 73% of cases (P = 0.21 compared with the normal group). In 10% and 2% of cases, the IOP could not be measured using the GT and RT, respectively. Conclusions: The results were similar for both tonometers. In the altered corneas, the IOP could be difficult to obtain with the GT because of distorted half-circles. The 1-mm-diameter disposable RT tip facilitated obtaining measurements without anesthetic drops, which avoids infections. The RT could be useful in routine clinical settings when measuring IOP in corneas with pathologies.

Diagnostic ability of macular nerve fiber layer thickness using new segmentation software in glaucoma suspects.

PURPOSE To assess the capacity of internal retinal layer thickness measurements made at the macula using new spectral-domain optical coherence tomography (OCT) software to distinguish between healthy subjects and those with suspected glaucoma. The diagnostic performance of such measurements also was compared with that of conventional peripapillary retinal nerve fiber layer (RNFL) thickness measurements. METHODS The study included 38 subjects with suspected glaucoma and 38 age-matched healthy subjects. In one randomly selected eye of each participant, thickness measurements at the level of the macula were made of the nerve fiber layer (mRNFL), the ganglion cell layer (GCL), and the ganglion cell complex (GCC; GCL + internal plexiform layer) through automated OCT segmentation. Peripapillary RNFL thickness (pRNFL) also was determined using the conventional scan. RESULTS As the only variable showing intergroup variation, mRNFL in the glaucoma suspects was significantly thinner in the quadrants inner inferior (P = 0.003), inner temporal (P = 0.010), and outer inferior (P = 0.017). The variable best able to discriminate between the two groups was inner inferior mRNFL thickness, as indicated by an area below the receiver operating characteristic (ROC) curve of 0.742. CONCLUSIONS Macular RNFL thickness measurements showed an improved diagnostic capacity over the other variables examined to distinguish between healthy subjects and glaucoma suspects.