Paulo Rodrigues Fernandes

Comparison of the ICare® rebound tonometer with the Goldmann tonometer in a normal population

The aim of this study was to evaluate the accuracy of measurement of intraocular pressure (IOP) using a new induction/impact rebound tonometer (ICare®) in comparison with the Goldmann applanation tonometer (AT).

Implantable Collamer Posterior Chamber Intraocular Lenses: A Review of Potential Complications

PURPOSE To review the peer-reviewed literature reporting postoperative complications of the most recent models of Visian Implantable Collamer posterior chamber intraocular lenses (ICL, STAAR Surgical Co). METHODS A literature search of the PubMed database was performed to identify all articles related to ICL complications. Articles were obtained and reviewed to identify those that reported complications using the latest ICL designs. RESULTS Cataract was the major postoperative complication reported: 136 (5.2%) in 2592 eyes. Of those, 43.4% (n=59) were reported within 1 year, 15.4% (n=21) between 1 and 3 years, and 35.3% (n=48) ≥ 3 years after ICL implantation. Twenty-one (15.4%) cataracts were reported as surgically induced, 46 (33.8%) eyes had poor vault (<200 μm), and cataract surgery was carried out in 27.9% (n=38) of eyes. Early acute intraocular pressure increase was also reported to be relatively frequent, whereas acute pupillary block was less frequent and mostly resolved with additional iridotomies. A total of 42 ICLs were explanted due to cataract and IOP. Reported endothelial cell loss varied from 9.9% at 2 years to 3.7% 4 years postoperatively. This loss was reported to be more pronounced within the first 1 to 2 years, with stability or lower progression after that time. CONCLUSIONS The majority of reported complications after ICL implantation are cataract formation. The improvements in lens geometry and more accurate nomograms applied to the selection of the lens to be implanted, in addition to the surgeons learning curve, might be factors in the decreased occurrence of postoperative complications reported currently.

Posterior chamber collagen copolymer phakic intraocular lenses to correct myopia : five-year follow-up

PURPOSE: To evaluate the long‐term safety and efficacy of posterior chamber collagen copolymer phakic intraocular lens (pIOL) implantation to correct myopia. SETTING: Fernández‐Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Cohort study. METHODS: Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, pIOL vault, endothelial cell loss, and adverse events were evaluated for 5 years after implantation of the Visian Implantable Collamer Lens pIOL for moderate to high myopia. RESULTS: The mean spherical equivalent (188 eyes) decreased from −11.17 diopters (D) ± 3.40 (SD) preoperatively to −0.88 ± 0.72 D 5 years postoperatively. The mean change in refraction from 1 month to 5 years was −0.65 ± 0.65 D. The mean UDVA and CDVA (Snellen decimal) were 0.69 ± 0.26 and 0.83 ± 0.15, respectively. The mean safety and efficacy indices were 1.27 ± 0.33 and 0.89 ± 0.35, respectively. No eye lost more than 2 lines of visual acuity; 70% achieved 0.80 or better CDVA. Three eyes (1.6%) developed late anterior subcapsular cataract that was clinically significant in 1 case, leading to pIOL removal and phacoemulsification. Of the 3 eyes (1.6%) with a mild transient increase in intraocular pressure (up to 27 mm Hg), none required a second surgical procedure or prolonged topical medication. The total endothelial cell loss (considered cumulatively at consecutive intervals through 5 years) was 7.7%. There was a tendency toward decreased pIOL vault decrease over time. No vision‐threatening complications occurred. CONCLUSION: Implantation of the collagen copolymer pIOL for moderate to high myopia was safe and effective and provided long‐term predictable, stable refractive results. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Collagen copolymer toric posterior chamber phakic intraocular lens in eyes with keratoconus.

PURPOSE: To assess the safety, efficacy, stability, and predictability of collagen copolymer toric phakic intraocular lens (pIOL) implantation to correct myopia and astigmatism in eyes with keratoconus. SETTING: Fernández‐Vega Ophthalmological Institute, Oviedo, Spain. METHODS: This prospective study comprised keratoconic eyes that had implantation of a toric Intraocular Collamer Lens. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, and postoperative complications were evaluated 1, 3, 6, and 12 months postoperatively. RESULTS: Preoperatively, the mean spherical equivalent in the 30 eyes (21 patients) was −5.38 diopters (D) ± 3.26 (SD) (range −13.50 to −0.63 D) and the mean cylinder, −3.48 ± 1.24 D (range −1.75 to −6.00 D). At 12 months, 86.7% of the eyes were within ±0.50 D of the attempted refraction and all eyes were within ±1.00 D. For the astigmatic components J0 and J45, 83.3% of eyes and 86.7% of eyes, respectively, were within ±0.50 D. The mean Snellen UDVA was 0.81 ± 0.20 and the mean CDVA, 0.83 ± 0.18; CDVA was 20/40 or better in 29 eyes 96.7% of eyes and 20/25 or better in 22 eyes (73.3%). No eyes lost more than 2 lines of CDVA; 29 eyes (96.7%) maintained or gained 1 or more lines. The efficacy index was 1.07 and the safety index, 1.16. There were no complications or adverse events. CONCLUSIONS: The results confirm that toric ICL implantation is a predictable, effective procedure to correct ametropia in eyes with keratoconus. Predictability and stability were achieved early and remained fairly stable up to 12 months. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Correlations between corneal biomechanical properties measured with the ocular response analyzer and ICare rebound tonometry.

PurposeTo investigate the biomechanical properties of the normal cornea, and correlate them with central and peripheral corneal thickness and age. MethodsSeventy-six right eyes of volunteers were measured with Ocular Response Analyzer (ORA), ICare rebound tonometry and an ultrasound pachymeter at corneal center and at 4 mm from corneal center in the nasal and temporal directions. ResultsICare readings were significantly correlated with central and peripheral corneal thickness and corneal biomechanical properties. Corneal resistance factor was the biomechanical parameter with the higher correlation with ICare intraocular pressure (IOP) values. ICare tonometry at center and Goldmann equivalent IOP obtained with ORA were significantly higher for thicker than thinner corneas (P<0.05). IOP compensated for corneal properties with the ORA was lower than the remaining IOP values measured in the study. Higher correlation was found between Goldmann equivalent IOP with ORA and ICare IOP values. ConclusionsIOP values obtained with the rebound tonometer are higher in thicker corneas and are positively correlated with biomechanical corneal parameters, namely corneal resistance factor. Although corneal thickness plays a significant role in rebound tonometry, elastic and viscous properties of the cornea seem to play a significant role in the interaction of the tonometer probe with the ocular surface. However, the mechanism behind this process is presently unknown.

Collagen copolymer toric posterior chamber phakic intraocular lens for myopic astigmatism: One-year follow-up

PURPOSE: To assess the predictability, efficacy, safety, and stability of collagen copolymer toric phakic intraocular lens (pIOL) implantation to correct moderate to high myopic astigmatism. SETTING: Fernández‐Vega Ophthalmological Institute, Oviedo, Spain. METHODS: This study comprised eyes that had implantation of a toric Intraocular Collamer Lens for moderate to high myopic astigmatism. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, pIOL vault, and adverse events were evaluated over 12 months. RESULTS: Preoperatively, the mean sphere in the 55 eyes was −4.65 diopters (D) ± 3.02 (SD) (range −0.50 to −12.50 D) and the mean cylinder, −3.03 ± 0.79 D (range −1.25 to −4.00 D). At 12 months, the mean Snellen decimal UDVA was 0.80 ± 0.20 and the mean CDVA, 0.85 ± 0.18; 62.0% of eyes had a CDVA of 20/20. More than 50.0% of eyes gained 1 or more lines of CDVA. The treatment was highly predictable for spherical equivalent (SE) (r2 = 0.99) and astigmatic components J0 (r2 = 0.97) and J45 (r2 = 0.99). Of the eyes, 94.5% were within ±0.50 D of the attempted SE and all were within ±1.00 D. For J0, 94.5% of eyes were within ±0.50 D and for J45, 98.2% of eyes; all eyes were within ±1.00 D. The efficacy index was 0.95 at 3 months and 1.08 at 1 year. CONCLUSIONS: The UDVA and CDVA with toric pIOLs were good and highly stable over 12 months, confirming the procedure is safe, predictable, and effective for correction of moderate to high astigmatic. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Objective vs subjective vault measurement after myopic implantable collamer lens implantation.

PURPOSE To evaluate the relationship between subjective measurements of vault and objective values measured with Visante optical coherence tomography (OCT) in eyes receiving an implantable contact lens (ICL) for myopia correction. DESIGN Observational cross-sectional study. METHODS SETTING Fernández-Vega Ophthalmological Institute, Oviedo, Spain. PATIENTS Four hundred and fifty-two eyes from 246 patients were elected to be implanted with a Visian ICL V4 (STAAR Surgical Inc, Monrovia, California, USA). OBSERVATION PROCEDURES Subjective and objective measurements of vault after implantation of ICL. MAIN OUTCOME MEASURES Subjective vault classified in 5 levels assessed using an optical section during slit-lamp examination. Objective vault was measured with Visante OCT (Carl Zeiss Meditec Inc, Dublin, California, USA). RESULTS Average values of objective and subjective vault were 414 +/- 228 microm and 2.1 +/- 1.0, respectively and both parameters were highly correlated (r = 0.82; P < .001). Differences in average objective vault were statistically significant among the 5 groups of subjective vault (P < .001). Subjective vault 0 corresponded to a mean OCT value of 62 +/- 49 microm with 99% confidence interval (CI) [38; 86] microm; eyes with vault 1 to 203 +/- 93 microm with 99% CI [176; 230] microm; eyes with vault 2 to 402 +/- 131 microm with 99% CI [378; 425] microm; eyes with vault 3 to 594 +/- 146 microm, 99% CI [554; 633] microm; and vault 4 to 794 +/- 182 microm with 99% CI [713; 875] microm. CONCLUSIONS Subjective and objective values of vault are highly correlated. In 99% of cases within the CI, objective values for eyes subjectively classified within a certain level vary within a narrow interval (+/-25 to 80 microm) around the mean value, and this interval is characteristic of each subjective level.

Central vault after phakic intraocular lens implantation: Correlation with anterior chamber depth, white-to-white distance, spherical equivalent, and patient age

PURPOSE: To compare the central postoperative vault of a phakic intraocular lens (pIOL) to correct myopia, myopic astigmatism, and hyperopia and identify ocular and lens parameters that might predict the vault amount. SETTING: Fernández‐Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Cohort study. METHODS: Three months after implantation of Implantable Collamer Lens pIOLs to correct myopia, hyperopia, and myopic astigmatism, central vault was measured using optical coherence tomography. Patients were divided into groups according to the preoperative anterior chamber depth (ACD) to compare the effects of ACD, white‐to‐white (WTW) distance, and lens diameter on postoperative pIOL vault. RESULTS: Hyperopic pIOLs had statistically significantly lower vault followed by myopic pIOLs and toric pIOLs, which had a higher mean value and narrower range (260 to 860 μm). Measured vaults had a positive correlation with preoperative ACD (r = .32, P<.001) and WTW (r = .29, P<.001) and a negative correlation with preoperative spherical equivalent (SE) (r = −0.21, P<.001) and patient age (r = −0.12, P=.025). Eyes with a vault of 250 μm or less had a shallower ACD than eyes with a vault between 250 μm and 750 μm (mean difference −0.11 mm; P=.012) and those with a vault greater than 750 μm (mean difference −0.25 mm; P<.001). CONCLUSIONS: Central vaulting was lower in hyperopic eyes. Current nomograms for pIOL diameter selection based on ACD and WTW might yield ideal vault and may have to be adjusted for older patients, shallower ACD, lower WTW, and lower SE. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Age differences in central and peripheral intraocular pressure using a rebound tonometer.

Aim: To evaluate the influence of age on the measurements and relationships among central and peripheral intraocular pressure (IOP) readings taken with a rebound tonometer. Methods: The IOPs were measured using the ICare rebound tonometer on the right eyes of 217 patients (88 men and 129 women) aged 18–85 years (mean 45.9 (SD 19.8) years), at the centre and at 2 mm from the nasal and temporal limbus along the horizontal meridian. Three age groups were established: young (⩽30 years old; n = 75), middle aged (31–60 years old; n = 77) and old patients (>60 years old; n = 65). Results: A high correlation was found between the central and peripheral IOP readings, with the central readings being higher than the peripheral ones. Higher IOP values for the central location were found in the younger patients. Older patients had significantly lower temporal IOP readings than those for the remaining two groups (p<0.001), whereas no significant differences were found among groups when IOP was measured at the central and nasal locations. A significant decrease was observed in the nasal and temporal IOP readings as the age increased (p = 0.011 and 0.006, respectively). Conclusion: Older patients had lower IOP values than the middle-aged and younger patients in the temporal peripheral location. A negative correlation was found between age and IOP by rebound tonometry in the corneal periphery but not in its centre.

The influence of cycloplegia in objective refraction

The purpose of this study was to compare refractions measured with an autorefractor and by retinoscopy with and without cycloplegia. The objective refractions were performed in 199 right eyes from 199 healthy young adults with a mean age of 21.6 ± 2.66 years. The measurements were performed first without cycloplegia and repeated 30 min later with cycloplegia. Data were analysed using Fourier decomposition of the power profile. More negative values of component M and J0 were given by non‐cycloplegic autorefraction compared with cycloplegic autorefraction (p < 0.0001). However more positive values for the J45 vector were given by non‐cycloplegic autorefraction, although this difference was not statistically significant (p = 0.233). By retinoscopy, more negative values of component M were obtained with non‐cycloplegic retinoscopy (p < 0.0001); for the cylindrical vectors J0 and J45 the retinoscopy without cycloplegia yields more negative values (p = 0.234; p = 0.112, respectively). Accepting that differences between cycloplegic and non‐cycloplegic retinoscopy are only due to the accommodative response, the present results confirm that when performed by an experienced clinician, retinoscopy is a more reliable method to obtain the objective starting point for refraction under non‐cycloplegic conditions.