Agreement between corneal diameter measurements obtained with an optical biometer and a Placido-based topographer.

PURPOSE: The purpose of this study was to compare the white-to-white distance measurements of two devices (IOL Master 500 and Atlas corneal topographer) commonly used in clinical practice to determine if they were interchangeable. Providing information on instrument interchangeability could eliminate several unnecessary tests and consequently reduce the economic burden for the patient and society. METHODS: In this prospective, comparative case series, the white-to-white distance was measured by independent examiners using the Atlas topographer (Carl Zeiss Meditec) and the IOL Master 500 (Carl Zeiss Meditec). One eye each of 184 patients was tested. Statistical analyses were performed using a paired t-test, Pearson correlation analysis, and Bland-Altman analysis to compare the measurement methods. RESULTS: The mean white-to-white distance measurements with the Atlas topographer and the IOL Master 500 were 12.20 ± 0.44 mm and 12.12 ± 0.41 mm, respectively (p<0.001). The mean white-to-white difference between the two devices was 0.07 mm (95% confidence interval of mean difference: 0.04-0.11 mm). The Pearson correlation coefficient between the two devices was 0.85 (p<0.0001). The 95% limits of agreement between the two devices were -0.38 mm to 0.53 mm. CONCLUSIONS: The Atlas topographer and IOL Master 500 can be used interchangeably with respect to white-to-white distance measurements, as the range of differences is unlikely to affect clinical practice and decision making.

Prevalence of corneal astigmatism in cataract surgery candidates at a public hospital in Brazil.

PURPOSE: To assess the frequency of corneal astigmatism before cataract surgery in a Brazilian sample. METHODS: This clinic-based cross-sectional study was conducted at the Bonsucesso Federal Hospital, Rio de Janeiro, Brazil. Charts of patients who underwent cataract surgery over a two-year period were retrospectively reviewed, and preoperative keratometric measurements were collected and analyzed. RESULTS: A total of 1707 eyes of 1045 patients were enrolled. The corneal astigmatism was less than 1.0 D in 971 eyes (56.9%), 1.0-1.99 D in 496 eyes (29.1%), 2.0-2.99 D in 157 eyes (9.2%), and more than 3.0 D in 83 eyes (4.9%). The mean corneal astigmatism was 0.92 ± (SD) 0.96 D (range 0 - 10.25 D). CONCLUSION: Over 40% of the patients undergoing cataract surgery enrolled in this study had more than 1.0 D of corneal astigmatism and may benefit from the use of toric intraocular lenses. These data can be useful for planning to make this technology available for patients.

Accelerated corneal collagen crosslinking: Technique, efficacy, safety, and applications.

Corneal collagen crosslinking (CXL) is an approach used to increase the biomechanical stability of the stromal tissue. Over the past 10 years, it has been used to halt the progression of ectatic diseases. According to the photochemical law of reciprocity, the same photochemical effect is achieved with reduced illumination time and correspondingly increased irradiation intensity. Several new CXL devices offer high ultraviolet-A irradiation intensity with different time settings. The main purpose of this review was to discuss the current use of different protocols of accelerated CXL and compare the efficacy and safety of accelerated CXL with the efficacy and safety of the established conventional method. Accelerated CXL proved to be safe and effective in halting progression of corneal ectasia. Corneal shape responses varied considerably, as did the demarcation line at different irradiance settings; the shorter the exposure time, the more superficial the demarcation line. FINANCIAL DISCLOSURE: Dr. Santhiago is a consultant to Ziemer Ophthalmic Systems AG and Alcon Laboratories, Inc. None of the authors has a financial or proprietary interest in any material or method mentioned.

Predictability and Vector Analysis of Laser In Situ Keratomileusis for Residual Errors in Eyes Implanted With Different Multifocal Intraocular Lenses.

PURPOSE: To investigate potential differences in predictability, efficacy, and safety of corneal excimer laser to correct residual myopia, hyperopia, and astigmatism in eyes previously implanted with multifocal intraocular lenses using distinct optical surfaces and platforms for multifocality. METHODS: This prospective comparative study included 37 eyes submitted to laser in situ keratomileusis correction for residual errors after implantation of either an apodized diffractive-refractive (Restor) or a full-diffractive (Tecnis) multifocal intraocular lens. Data analysis included investigation of predictability, efficacy, and safety of excimer laser surgery to correct residual errors. A double-angle plot, using vector analysis, was also created to evaluate predictability of astigmatism correction. RESULTS: At 6-month follow-up, statistical analyses revealed a significant improvement when comparing preoperative (0.51 ± 0.25 and 0.44 ± 0.18) and postoperative values (0.17 ± 0.10 and 0.09 ± 0.07) of uncorrected distance visual acuity (P < 0.0001 and <0.0001), preoperative (0.92 ± 0.61 and 1.02 ± 0.45) and postoperative values (0.33 ± 0.23 and 0.19 ± 0.17) of manifest refractive spherical equivalent (P = 0.0006 and <0.0001), and preoperative (-1.08 ± 0.70 and -0.65 ± 0.42) and postoperative values (-0.25 ± 0.28 and -0.14 ± 0.21) of astigmatism (P < 0.0001 and <0.0001) in eyes implanted with Restor and Tecnis, respectively. Vector analysis revealed a predictable correction of astigmatism in all groups. Ninety-two percent of total eyes achieved a manifest refractive spherical equivalent within ±0.5 of emmetropia. CONCLUSIONS: Corneal excimer laser refractive surgery seems to be equally effective to correct different residual errors, including astigmatism, in eyes implanted with intraocular lenses with various platforms for multifocality.

Longitudinal Evaluation of Central Corneal Thickness in Patients With Systemic Sclerosis.

PURPOSE: To investigate the longitudinal change of central corneal thickness (CCT) in patients with systemic sclerosis (SSc) and to elucidate whether it contributes to misinterpretation of intraocular pressure (IOP) in this group of patients. METHODS: Twenty patients with SSc and 20 sex- and age-matched controls were examined at 2 visits 5 years apart. Age, sex, race, subtype of SSc, disease duration, autoantibody profile, use of disease-modifying antirheumatic drugs (DMARDs), best-corrected visual acuity, spherical equivalent refraction, IOP, and CCT were recorded. IOP was assessed by applanation tonometry and CCT by ultrasonic pachymetry. RESULTS: CCT decreased by 7.2 µm [95% confidence interval (CI), -2.1 to -12.2 µm] between the first and second measurements (P = 0.008) in patients with SSc and by 2.4 µm (P = 0.39, 95% CI, -8.0 to 3.3 µm) in the control group. Considering patients with SSc, CCT decreased by a mean of 11.6 µm [95% CI, -4.3 to -19.0 µm (P = 0.007)] among those taking DMARDs at the second visit and by 4.2 µm [95% CI, -3.0 to -11.5 µm (P = 0.2)] in patients not taking any DMARDs. There was no statistically significant change in IOP between the 2 visits for either the SSc group (P = 0.84) or the control group (P = 0.29). Mean change in CCT was not associated with either IOP at first visit or with change in IOP in SSc patients. CONCLUSIONS: CCT decreased with time in SSc. However, the slight rates of thinning observed are unlikely to considerably influence applanation tonometry or clinical decision-making over the short to intermediate term.

Comparison of eyedrop instillation technique with and without a delivery device in inexperienced patients.

PURPOSE: To compare the instillation of eyedrops with and without Xal-Ease® delivery device in inexperienced patients based on patient observation and answers to a questionnaire. METHODS: This prospective study included consecutive patients considered inexperienced in instilling eyedrops. After a short explanation about the methods, drop instillation technique was evaluated with and without the device. Subjects also completed a survey regarding drop administration and satisfaction. Successful instillation was defined as instilling a single drop in the eye without touching the eye with the bottle tip on the first attempt. RESULTS: The overall rate of successful instillation (43%) was the same for both techniques (with or without the device). Without the device, the bottle tip touched the eye or periocular tissues in 8 eyes (35%) compared with 0 (0%) with the Xal-Ease® (p<0.01). The number of eyedrops dispensed was significantly higher with Xal-Ease® (1.4 ± 0.5 without the device versus 2.0 ± 1.1 with Xal-Ease®; p = 0.03). Using the Xal-Ease® device, 13 (57%) of the patients needed to make more than one attempt, versus 6 (26%) patients without the device (p = 0.04). Overall, 9 (39%) preferred traditional instillation and 14 (61%) preferred to use the device. CONCLUSIONS: Xal-Ease® successfully decreased mechanical contact of the tip of the bottle. However, Xal-Ease® failed to help inexperienced subjects dispense fewer drops, or improve accuracy, suggesting that more training might be needed to achieve a good eyedrop administration technique with the device.

Assessment of Central Corneal Thickness in Different Subtypes of Systemic Sclerosis.

PURPOSE: To compare central corneal thickness between patients with diffuse cutaneous systemic sclerosis and limited cutaneous systemic sclerosis. METHODS: A total of 53 consecutive patients with systemic sclerosis were enrolled in this study. All subjects were screened for age, gender, classification of disease subtype, autoantibody profile, duration of disease, organ involvement, current treatment, tear break-up time, Schirmer test, and measurement of the central corneal thickness with an ultrasonic pachymeter. RESULTS: No statistically significant differences were found in terms of age, sex, and duration of the disease, and dry eye evaluation between systemic sclerosis subsets. The mean central corneal thickness was 535.3 ± 37.6 µm (range, 471-619 µm) in diffuse cutaneous systemic sclerosis patients, and 539.3 ± 37.1 µm (range, 484-651 µm) in limited cutaneous systemic sclerosis (p = 0.71). CONCLUSIONS: Central corneal thickness in patients with diffuse cutaneous systemic sclerosis is not different from the one in limited cutaneous systemic sclerosis.

Corneal involvement in systemic inflammatory diseases.

Corneal involvement in patients with systemic inflammatory disorders may be sight threatening, and it may be associated with a life-threatening disease. Significant systemic inflammatory diseases in this context are autoimmune connective tissue diseases, systemic autoimmune dermatological disorders, and autoimmune diseases of the lacrimal system. Keratoconjunctivitis sicca is usually the most common ocular finding in these patients. Peripheral ulcerative keratitis is a rare condition usually associated with increased ocular morbidity and also mortality, as it might act as an indicator of a more widespread vasculitis. Corneal biomechanical properties may also be altered in connective tissue diseases. Although recent studies suggest that the risk for corneal complications after ocular surgery in patients with quiescent autoimmune disease is minimal, caution is still recommended, as the knowledge about the corneal wound-healing process and the corneal biomechanical properties in these patients is not yet fully understood. This article reviews corneal abnormalities and characteristics in the setting of systemic inflammatory diseases.

The accuracy of Goldmann applanation tonometry over silicone hydrogel contact lenses in patients with glaucoma.

PURPOSE: To investigate the accuracy of measuring intraocular pressure over a silicone hydrogel contact lens using Goldmann applanation tonometry in eyes with glaucoma. METHODS: This was a prospective, randomized study and enrolled 28 patients (28 right eyes) with primary open angle glaucoma. Intraocular pressure was taken with and without a silicone hydrogel contact lens (-0.50 D), in situ (using Goldmann applanation tonometry), in a randomized order of measurements. Statistical analysis was performed using paired t-test and Bland-Altman plot. RESULTS: The mean difference (± standard deviation) found between intraocular pressure measurement without (mean 16.7 ± 3.2 mmHg) and with (mean 17.3 ± 3.0 mmHg) contact lens was found to be -0.57 ± 2.3 mmHg (95% confidence interval, -1.5 to 0.3). No significant statistical difference was found between the two groups with paired t-test (p=0.19). The Bland Altman plot showed some evidence of increasing variability of differences between two measures of intraocular pressure, with increasing intraocular pressure. The 95% limits of agreement of the Bland Altman plot were unacceptably large (-5 mmHg to 3.9 mmHg). CONCLUSION: Agreement between Goldmann applanation tonometry with and without contact lenses seems to be poor in patients with glaucoma, especially for high intraocular pressure.

Effects of corneal cross-linking on contrast sensitivity, visual acuity, and corneal topography in patients with keratoconus.

PURPOSE: To assess the effects of corneal collagen cross-linking (CXL) on contrast sensitivity (CS), visual acuity, and corneal topography investigating possible predictors of efficacy. METHODS: Sixty-eight eyes of 34 patients with progressive keratoconus were enrolled in this prospective study. CXL was performed in one eye and the other eye was left untreated as a control. CS, best spectacle-corrected visual acuity (BSCVA), simulated keratometry in the steepest meridian (SimK-s), mean power in the central 3-mm zone (C-MP), mean power in the paracentral 3- to 5-mm zone (P-MP), maximum keratometric power in the central zone (C-Kmax), and maximum keratometric power in the paracentral zone (P-Kmax) were evaluated at baseline, 40 days, 3 months, 6 months, 1 year, and after 2 years of follow-up. RESULTS: Treated eyes showed an improvement (P < 0.001) of +0.16 logCS and -0.16 logarithm of the minimum angle of resolution (logMAR) and a reduction in SimK-s of -0.61 diopter (D), C-Kmax -1.11 D, P-Kmax -0.99 D, C-MP -0.39 D, and P-MP -0.30 D. Of the treated eyes, 43.3% had a decrease in C-Kmax greater than 1 D, 50% by 0 to 0.99 D, and 6.7% had an increase of up to +0.89 D. Treated eyes with keratometric apex in the central 3-mm zone (CKA) improved BSCVA -0.19 logMAR and CS +0.19 logCS; whereas in treated eyes with paracentral keratometric apex (PKA), the improvement was -0.13 logMAR and +0.16 logCS. CONCLUSIONS: CXL with riboflavin and UV-A improved CS and inhibited the progression of keratoconus. As a predictor of treatment efficacy, eyes with CKA showed greater improvement in BSCVA after CXL when compared with eyes with PKA.

Role of optical coherence tomography on corneal surface laser ablation.

This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages. Which of the current imaging instruments is a better choice depends on the specific application. In laser in situ keratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. In addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.

Prevalence of eye disease in Brazilian patients with psoriatic arthritis.

OBJECTIVES: The aim of this study was to report the type and frequency of ocular manifestations in Brazilian psoriatic arthritis patients. METHODS: We conducted a cross-sectional study in a Brazilian tertiary hospital. The test group included 40 patients who had psoriatic arthritis according to the Classification Criteria for Psoriatic Arthritis. A control group of 40 individuals was matched for age and gender. All of the patients underwent ophthalmic evaluation, which included best-corrected visual acuity, slit lamp and fundus examinations, and dry eye diagnostic tests (Schirmer I, tear breakup time and rose bengal). Demographic parameters were also evaluated. RESULTS: The mean age of the patients was 53.9±13.1 years; the mean disease duration was 8±10.5 years. Most of the patients were women (60%), and the majority had polyarticular disease (57.5%). Several ocular abnormalities were found, including punctate keratitis, pinguecula, blepharitis, pterygium, cataract, glaucoma, uveitis, and retinal microvascular abnormalities. There were no significant differences in the rates of these abnormalities compared with the control group, however. The Keratoconjunctivitis sicca and dry eye diagnostic tests were more often positive in the patients with psoriatic arthritis than in the control group. CONCLUSIONS: In this study, keratoconjunctivitis sicca was the most common ocular finding related to psoriatic arthritis. Therefore, we recommend early ophthalmologic evaluations for all psoriatic arthritis patients who complain of eye symptoms.

Evaluation of dry eye signs and symptoms in patients with systemic sclerosis.

BACKGROUND: One of the most frequent ocular features of systemic sclerosis (SSc) is dry eye disease (DED), which has been identified to occur in 37-79% of patients. Although several studies have found weak or no correlations between symptoms and signs of dry eye, symptoms are often the motivation for seeking eye care, and are therefore a critical outcome measure when assessing treatment effect. The aim of this study is to evaluate the impact of symptoms of dry eye on vision-related quality of life in patients with systemic sclerosis, and to investigate the relation between clinical tests and symptoms of dry eye in these patients. METHODS: In this cross-sectional study, 45 consecutive patients with SSc were enrolled. For evaluation of the symptoms the "Ocular Surface Disease Index (OSDI)" questionnaire was applied to all patients. After that, all individuals were submitted to a full ophthalmic examination, including the following tests: tear break-up time, Schirmer I, rose bengal staining. Patients were then grouped into dry eye and non-dry eye groups with regard to the diagnosis of dry eye. Mann-Whitney test was used to compare continuous variables, whereas the Fisher exact test was used to compare categorical data between groups. Spearman's correlation test was used to analyze the correlations between clinical tests and OSDI scores. P values <0.05 were considered significant. RESULTS: Dry eye disease was diagnosed in 22 patients (48.9%). Other ocular surface abnormalities found were: blepharitis (40% of the patients), pterygium (15.6%), pinguecula (82.2%), and superficial punctate keratitis (26.7%). Among the 45 patients, 29 patients (64.4%) had symptoms of ocular surface disease. The mean OSDI score was 26.8 ± 25.8 (SD). There were no statistically significant differences in OSDI scores between DED and non-DED patients. No substantive correlations were found between OSDI scores and TBUT, Schirmer I, or rose bengal staining score, and none of the observed correlations reached statistical significance. CONCLUSION: Symptoms of dry eye have a moderate impact on vision-related quality of life in patients with systemic sclerosis and do not correlate well with clinical findings.

Clinical and histopathological outcomes of subconjunctival triamcinolone injection for the treatment of acute ocular alkali burn in rabbits.

PURPOSE: To evaluate the efficacy and safety of subconjunctival injection of triamcinolone in the treatment of acute ocular alkali burn in rabbits. METHODS: Two groups of 5 rabbits were subjected to alkali burn (1 N NaOH). One group was treated with 1 subconjunctival injection of 0.3 mL of triamcinolone and the other with 1 subconjunctival injection of 0.3 mL of 0.9% saline. The affected corneas were observed for vascularization and opacity approximately 10 minutes after the burn and also after 7, 14, and 21 days. Photographs were taken for observation and statistical analyses. At all time intervals, the corneas were classified according to predetermined scores. Twenty-one days after the treatment, the animals were anesthetized, and their eyes were enucleated and processed for histopathology. RESULTS: Greater vascularization and opacity appeared in the animals that were treated with saline than in those treated with subconjunctival triamcinolone (vascularization: 7 days, P = 0.0107; 14 days, P = 0.0099; and 21 days, P = 0.0088; opacity: 7 days, P = 0.0079; 14 days, P = 0.0112; and 21 days, P = 0.0255). These results were also compatible with the morphological and statistical analyses, which revealed a more intense inflammatory process in the group treated with saline (P = 0.0317). No complications, such as corneal melting, perforation, or infection, were observed. CONCLUSIONS: Subconjunctival injection of triamcinolone may be a therapeutic option for the treatment of acute ocular burn because it reduced the corneal inflammatory process, opacity, and vascularization, with no apparent clinical changes in the general state of the animal.

Central corneal thickness in patients with systemic sclerosis: a controlled study.

PURPOSE: To compare the central corneal thickness (CCT) of patients with systemic sclerosis (SSc) and control subjects. METHODS: The study group comprised 37 consecutive patients with SSc, and the control group comprised 23 healthy individuals similar in age and sex. CCT value was measured by ultrasound pachymetry. RESULTS: In the SSc group, the mean CCT in the right eye was 534.9 ± 33.5 µm and 536.9 ± 32.4 µm in the left eye. In the control group, the mean CCT was 533.0 ± 32.9 µm in the right eye and 533.1 ± 33.6 µm in the left eye. The mean CCT was not significantly different in the SSc group compared with the control group for both the right (P = 0.83) and left (P = 0.67) eyes. CONCLUSIONS: CCT measurements do not significantly differ in patients with SSc compared with healthy control subjects.

Ocular findings in patients with systemic sclerosis.

OBJECTIVE: To evaluate the frequency and characteristics of ocular manifestations in outpatients with systemic sclerosis. METHODS: In this cross-sectional study, 45 patients with systemic sclerosis were enrolled. Data regarding demographics, disease duration and subtype, age at diagnosis, nailfold capillaroscopic pattern and autoantibody profile were collected, and a full ophthalmic examination was conducted. Parametric (Student's t-test) and nonparametric (Mann-Whitney U test) tests were used to compare continuous variables. Fisher's exact test was used to compare categorical data. P values < 0.05 were considered significant. RESULTS: Twenty-three subjects (51.1%) had eyelid skin changes; 22 (48.9%) had keratoconjunctivitis sicca, 19 (42.2%) had cataracts, 13 (28.9%) had retinal microvascular abnormalities and 6 (13.3%) had glaucoma. Eyelid skin changes were more frequent in patients with the diffuse subtype of systemic sclerosis and were associated with a younger age and an earlier age at diagnosis. Cataracts were presumed to be age-related and secondary to corticosteroid treatment. There was no association between demographic, clinical or serological data and keratoconjunctivitis sicca. The retinal microvascular abnormalities were indistinguishable from those related to systemic hypertension and were associated with an older age and a severe capillaroscopic pattern. CONCLUSIONS: Eyelid skin abnormalities and keratoconjunctivitis sicca were the most common ocular findings related to systemic sclerosis. Some demographic and clinical data were associated with some ophthalmic features and not with others, showing that the ocular manifestations of systemic sclerosis are characterized by heterogeneity and reflect the differences in the implicated pathophysiological mechanisms.

Ocular manifestations of HIV/AIDS.

HIV/AIDS affects millions of people worldwide. In the early stages of epidemic, eyes were affected because the CD4 T-lymphocytes count of HIV-infected patients dropped rapidly. Today, with the advent of highly active antiretroviral therapy, HIV-positive individuals live longer with a better quality of life. However, because a cure has not been found, many patients with HIV will develop ocular complications at some point. Ophthalmologists play an important role in the care of these patients. We must be prepared to work as part of a multidisciplinary staff, helping to understand the causes and try to achieve the best management of disease in order to prevent blindness. Most HIV-related ocular manifestations are discussed in this article, with a review of studies within the past 2 years. We hope government authorities, pharmaceutical industries, researchers and people from all nations stand together with two goals--less suffering and definitive cure.