Understanding Acanthamoeba Keratitis: An In-Depth Review of a Sight-Threatening Eye Infection.

Acanthamoeba keratitis (AK) is a rare but potentially sight-threatening corneal infection caused by the Acanthamoeba parasite. This microorganism is found ubiquitously in the environment, often in freshwater, soil, and other sources of moisture. Despite its low incidence, AK presents significant challenges due to delayed diagnosis and the complex nature of therapeutic management. Early recognition is crucial to prevent severe ocular complications, including corneal ulceration and vision loss. Diagnostic modalities and treatment strategies may vary greatly depending on the clinical manifestation and the available tools. With the growing reported cases of Acanthamoeba keratitis, it is essential for the ophthalmic community to thoroughly understand this condition for its effective management and improved outcomes. This review provides a comprehensive overview of AK, encompassing its epidemiology, risk factors, pathophysiology, clinical manifestations, diagnosis, and treatment.

Ocular Surface Disease in Patients With Atopic Dermatitis Treated With Dupilumab: A Prospective Case-Control Study.

PURPOSE: The aim of this study was to evaluate the variation of dry eye disease (DED) prevalence in patients with atopic dermatitis (AD) treated with dupilumab. METHODS: This prospective case-control study included consecutive patients with moderate-to-severe AD scheduled for dupilumab between May and December 2021 and healthy subjects. DED prevalence, the Ocular Surface Disease Index, tear film breakup time test, osmolarity, Oxford staining score, and Schirmer test results were collected at baseline, 1 month, and 6 months after dupilumab therapy. The Eczema Area and Severity Index was assessed at baseline. Ocular side effects and discontinuation of dupilumab were also recorded. RESULTS: Seventy-two eyes from 36 patients with AD treated with dupilumab and 36 healthy controls were included. Prevalence of DED increased from 16.7% at baseline to 33.3% at 6 months in the dupilumab group ( P = 0.001), whereas it remained unchanged in the control group ( P = 0.110). At 6 months, the Ocular Surface Disease Index and Oxford score increased (from 8.5 ± 9.8 to 11.0 ± 13.0, P = 0.068, and from 0.1 ± 0.5 to 0.3 ± 0.6, P = 0.050, respectively), the tear film breakup time test and Schirmer test results decreased (from 7.8 ± 2.6 s to 7.1 ± 2.7 s, P < 0.001, and from 15.4 ± 9.6 mm to 13.2 ± 7.9 mm, P = 0.036, respectively) in the dupilumab group, whereas they remained stable in the control group ( P > 0.05). Osmolarity was unchanged (dupilumab P = 0.987 and controls P = 0.073). At 6 months after dupilumab therapy, 42% of patients had conjunctivitis, 36% blepharitis, and 2.8% keratitis. No severe side effects were reported, and none of the patients discontinued dupilumab. No association between Eczema Area and Severity Index and DED prevalence was shown. CONCLUSIONS: DED prevalence increased in patients with AD treated with dupilumab at 6 months. However, no severe ocular side effects were found and no patient discontinued therapy.

Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery.

Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use.

Macular Pigment Density and Quantitative Fundus Autofluorescence in Young Healthy Subjects.

Purpose: To measure macular pigment (MP) and find possible correlation between heterochromatic flicker photometry (HFP) and quantitative autofluorescence (qAF) in young healthy subjects. Methods: We enrolled 80 eyes of 40 young healthy subjects. Macular pigment optical density (MPOD) was automatically calculated with a macular pigment screener (MPS; MPODHFP). We calculated qAF comparing gray levels (GL) of qAF images with GL of internal reference of a confocal scanning laser ophthalmoscopy. A raster of concentric rings was used to automatically calculate foveal qAF (qAFF) values (0°-1.2°); inner ring (1.3°-4.3°; qAF3); middle ring (4.5°-7°; qAF6); and outer ring (7.2°-9.7°; qAF8). The test-retest coefficient of repeatability was calculated with Bland-Altman method. The between-eyes coefficient of agreement and correlation between the two techniques were calculated. Finally, an estimation of MPOD from qAF was performed (MPOD-AF), to find possible direct correlations with MPODHFP obtained with the MPS II. Results: Paired data sets of repeated measurements were not statistically different for MPS II (P = 0.66); log qAFF (P = 0.95); log qAF3 (P = 0.48); log qAF6 (P = 0.4); and log qAF8 (P = 0.56). Stepwise regression analysis showed negative correlation between MPS II and log qAFF values (R2 = 0.35) with Spearman coefficient (ρ) of -0.60 (P < 0.01) and log qAF3 (R2 = 0.18; ρ = -0.38.; P < 0.01). No correlation was found between MPS II and log qAF6 (ρ = 0.01, P = 0.93), neither with log qAF8 (ρ = -0.05, P = 0.66). Conclusions: In young healthy subjects, a negative correlation between qAF values and MPODHFP was found in the central degrees. However, qAF and HFP do not seem to be interchangeable: they represent two opposite ways of estimating MP.

Placido disk-based topography versus high-resolution rotating Scheimpflug camera for corneal power measurements in keratoconic and post-LASIK eyes: reliability and agreement.

AIM: To compare the repeatability/reproducibility of measurement by high-resolution Placido disk-based topography with that of a high-resolution rotating Scheimpflug camera and assess the agreement between the two instruments in measuring corneal power in eyes with keratoconus and post-laser in situ keratomileusis (LASIK). METHODS: One eye each of 36 keratoconic patients and 20 subjects who had undergone LASIK was included in this prospective observational study. Two independent examiners worked in a random order to take three measurements of each eye with both instruments. Four parameters were measured on the anterior cornea: steep keratometry (Ks), flat keratometry (Kf), mean keratometry (Km), and astigmatism (Ks-Kf). Intra-examiner repeatability and inter-examiner reproducibility were evaluated by calculating the within-subject standard deviation (Sw) the coefficient of repeatability (R), the coefficient of variation (CoV), and the intraclass correlation coefficient (ICC). Agreement between instruments was tested with the Bland-Altman method by calculating the 95% limits of agreement (95% LoA). RESULTS: In keratoconic eyes, the intra-examiner and inter-examiner ICC were >0.95. As compared with measurement by high-resolution Placido disk-based topography, the intra-examiner R of the high-resolution rotating Scheimpflug camera was lower for Kf (0.32 vs 0.88), Ks (0.61 vs 0.88), and Km (0.32 vs 0.84) but higher for Ks-Kf (0.70 vs 0.57). Inter-examiner R values were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The 95% LoA were -1.28 to +0.55 for Kf, -1.36 to +0.99 for Ks, -1.08 to +0.50 for Km, and -1.11 to +1.48 for Ks-Kf. In the post-LASIK eyes, the intra-examiner and inter-examiner ICC were >0.87 for all parameters. The intra-examiner and inter-examiner R were lower for all parameters measured using the high-resolution rotating Scheimpflug camera. The intra-examiner R was 0.17 vs 0.88 for Kf, 0.21 vs 0.88 for Ks, 0.17 vs 0.86 for Km, and 0.28 vs 0.33 for Ks-Kf. The inter-examiner R was 0.09 vs 0.64 for Kf, 0.15 vs 0.56 for Ks, 0.09 vs 0.59 for Km, and 0.18 vs 0.23 for Ks-Kf. The 95% LoA were -0.54 to +0.58 for Kf, -0.51 to +0.53 for Ks and Km, and -0.28 to +0.27 for Ks-Kf. CONCLUSION: As compared with Placido disk-based topography, the high-resolution rotating Scheimpflug camera provides more repeatable and reproducible measurements of Ks, Kf and Ks in keratoconic and post-LASIK eyes. Agreement between instruments is fair in keratoconus and very good in post-LASIK eyes.

Keraring Intrastromal Segment Depth Measured by Spectral-Domain Optical Coherence Tomography in Eyes with Keratoconus.

Purpose. To evaluate agreement between measured and intended distance of Keraring (Mediphacos, Belo Horizonte, Brazil) intracorneal ring segments from the anterior and posterior corneal surfaces. Methods. Twenty-six Keraring ICRS implanted in 24 keratoconic eyes were examined. The distance from the Keraring apex to the anterior corneal surface and the distance from the inner and the outer corners to the posterior corneal surface were measured 3 months postoperatively using spectral-domain optical coherence tomography. Agreement between measured distance and intended distance was assessed by calculating the absolute differences and 95% limits of agreement (95% LoA). Results. The mean absolute difference was significantly lower (p < 0.001) for the measurements taken at the inner corner (23.54 ± 15.90 µm) than that for those taken at the apex (108.92 ± 62.72 µm) and the outer corner (108.35 ± 56.99 µm). The measurements taken at the inner corner were within ±25 and ±50 µm of the intended distance in 15/26 (57.7%) and 24/26 (92.3%) cases, respectively, and showed the narrowest 95% LoA with the intended distance (-57.61 to 55.15 µm). Conclusions. The distance of the inner corner from the posterior corneal surface showed the best agreement with the intended distance. This measurement is suitable for determining whether the actual Keraring depth matches the intended depth.

Corneal Astigmatism Measurement by Ray Tracing Versus Anterior Surface-Based Keratometry in Candidates for Toric Intraocular Lens Implantation.

PURPOSE: To compare corneal astigmatism derived from total corneal refractive power (CATCRP), a ray-tracing method, with that derived from simulated keratometry (CASimK), an anterior surface-based method, in candidates for toric intraocular lens (IOL) implantation. DESIGN: Reliability analysis. METHODS: In 1 eye of 200 consecutive patients (mean age 71 ± 9 years) with cataract, a Pentacam HR (Oculus) was used to measure CATCRP and CASimK. Eyes with CATCRP >1 diopter (D) were defined as candidates for toric IOL implantation. The estimation difference between CATCRP and CASimK was analyzed by calculating the arithmetic, absolute, and vector differences between the 2 methods. RESULTS: Seventy-seven candidates were identified. In the candidates, CASimK was <1 D in 22% of cases and underestimated the astigmatism magnitude, on average, by -0.15 ± 0.34 D. The mean absolute and vector difference between CATCRP and CASimK was 0.31 ± 0.29 D and 0.30 ± 0.29 D × 180 degrees, respectively. The absolute and vector differences between the 2 methods were >0.50 D in 21 of 77 (27.2%) and 25 of 77 (32.5%) eyes, respectively; the proportions were significantly (P < .001) higher than in the eyes with CATCRP ≤1 D (0.8% and 9.8%, respectively). The difference in steep meridian alignment between CATCRP and CASimK was >5 degrees in 22.1% and >10 degrees in 2.6% of cases. CONCLUSION: The difference between CATCRP and CASimK, as calculated by Pentacam HR, is greater in candidates for toric IOL implantation than in the general population. That difference considerably influences the candidate and toric IOL power selection in a large proportion of cases.

Changing trends in corneal graft surgery: a ten-year review.

AIM: To review indications and corneal tissue use for penetrating and lamellar surgery between 2002 and 2011. METHODS: The surgical reports of corneal grafts performed during 2002-2011, using tissues supplied by the Eye Bank of Piedmont (Italy), were reviewed retrospectively. Patient demographic data, date of intervention, indication for surgery, and surgical technique used were recorded. Surgical techniques included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK). The χ (2) test was used to compare the distribution of indications and types of surgical technique used, for corneal grafts done during 2002-2006 versus those done during 2007-2011. RESULTS: The number of corneal grafts increased by 30.7% from 2002-2006 to 2007-2011 (from 1567 to 2048). Comparing the two periods, both main indications and surgical techniques changed significantly. In 2007-2011, the proportion of interventions for aphakic/pseudophakic bullous keratopathy (from 16.8% to 21.3%), graft failure (from 16.4% to 19.1%) and Fuchs endothelial dystrophy (from 12.8% to 16.7%) all increased significantly (P<0.05), while those for keratoconus decreased significantly (from 35.6% to 27.3%; P<0.001). In 2007-2011, the proportion of PK decreased significantly (from 92.4% to 57.2%; P<0.001) while that of EK and DALK went from 0.4% to 30.2% (P<0.001) and from 7.2% to 12.6% (P<0.001) respectively. CONCLUSION: During 2002-2011 the number of interventions increased significantly for corneal endothelial diseases and graft failure. The growing demand for interventions for these diseases corresponded to the widespread adoption of EK techniques. The use of DALK also increased, but more moderately than EK procedures.

Treatment for neovascular age related macular degeneration: The state of the art.

With the introduction in the clinical practice of drugs inhibiting vascular endothelial growth factor (VEGF) the visual outcomes of patients with neovascular age related macular degeneration (AMD) dramatically improved. Since 2006 repeated intravitreal injections of anti-VEGF became the standard of care for the treatment of neovascular AMD. This review provides an overview of available data form clinical trials supporting the use of anti-VEGF molecules for the treatment of this condition. Several questions remain open, in particular the regimen of treatment, the frequency of injection, the safety of the different drugs, and the poor response to the treatment in some cases. Therefore, new agents and alternative delivery are currently under evaluation.

In vivo confocal microscopic evaluation of corneal langerhans cells in dry eye patients.

PURPOSE: To assess inflammatory involvement of cornea in dry eye by means of confocal microscopy, evaluating the presence and distribution of Langherans cells (LCs). METHODS: 98 eyes of 49 subjects were enrolled: 18 subjects affected by Sjögren Syndrome Dry Eye (SSDE), 17 with Non-Sjögren Syndrome Dry Eye (NSSDE), 14 healthy volunteeers. Dry eye symptoms, tear film, ocular surface damage and corneal confocal microscopy were analized. RESULTS: A significant increase of LCs density was observed at sub-basal nerve plexus (SSDE = 79 cells/mm(2) andNDE = 22 cells/mm(2); p = 0,0031) and sub-epithelial nerve plexus (SSDE = 38 cells/mm(2) and NDE = 3 cells/mm(2); p = 0,0169) in central cornea of SSDE group. An increased number of LCs from the center to the periphery of the cornea was observed, significant only in healthy volunteers group. In dry eye patients there was an increase in LCs density in both peripheral and central cornea with a significant difference between NDE (14,66 cells/mm(2)) and SSDE (56,66 cells/mm(2)) only in central cornea (p = 0,0028). In SSDE group, mean density of LCs in central cornea results also superior to NSSDE group (29,33 cells/mm(2)). There was no correlation between LCs density and dry eye symptoms, tear film deficiency and ocular surface damage. CONCLUSION: This study demonstrates the activation of an inflammatory and immunological reaction in cornea of NSSDE and SSDE patients. Confocal microscopy can be an important diagnostic tool in evaluation and follow-up of dry eye disease.

Total spherical aberration of the cornea in patients with cataract.

PURPOSE: To investigate the distribution of corneal spherical aberration in patients with cataract using the Pentacam HR. METHODS: Consecutive cataract patients were examined using the Pentacam HR high-resolution rotating Scheimpflug camera (Oculus, Wetzlar, Germany). In one eye of each patient, the root-mean-square (RMS) of anterior, posterior, and total corneal spherical aberration Z4(0) was calculated by ray-tracing on an area of 6 mm diameter. The Pearson correlation coefficient (r) was used to assess correlations between Z4(0) RMS values and age/total corneal refractive power. The χ2 test was used to compare the proportion of eyes qualifying for spherically neutral or negatively aspheric (-0.17 and -0.27 µm) intraocular lenses (IOLs) by targeted level of residual spherical aberration. RESULTS: Fifty-seven men and 92 women were included (mean [±SD] age, 71.73 [±9.12] years). The RMS mean (±SD) values of Z4(0) were +0.353 (±0.132) µm, -0.121 (±0.034) µm, and +0.328 (±0.132) µm, respectively, for the anterior, posterior, and total cornea. The anterior, posterior, and total Z4(0) were on average significantly higher (p < 0.001) in women than in men. In both sexes, statistically significant (p < 0.05) age-related changes were found for the anterior and total Z4(0) but not for the posterior Z4(0) (p > 0.05). The total Z4(0) and total corneal refractive power were significantly correlated in men (p = 0.01) but not in women (p = 0.14). For postoperative targets of 0 ± 0.05/+0.10 ± 0.05 µm residual Z4(0), the proportion of eyes that would have qualified for implantation of negatively aspheric IOLs with -0.17 and with -0.27 µm was similar (61.1 and 56.3%, respectively; p = 0.09); significantly fewer eyes (6.7%) would have qualified for implantation of neutrally aspheric IOLs (p > 0.05). CONCLUSIONS: Total corneal Z4(0) measured by Pentacam HR might be higher than that reported in previous studies. In most patients, the implantation of commercially available negatively aspheric IOLs would partially compensate for the positive total corneal Z4(0).

Refractive error after cataract surgery combined with descemet stripping automated endothelial keratoplasty.

PURPOSE: To assess refractive error after cataract surgery combined with Descemet stripping automated endothelial keratoplasty using adjusted keratometric (K) readings to calculate intraocular lens (IOL) power. DESIGN: Prospective, interventional case series. METHODS: One eye of 39 consecutive patients with Fuchs endothelial dystrophy and cataract were included. To calculate IOL power before surgery, the Javal steep and flat K readings (Haag-Streeit) were adjusted by reducing their value by -1.19 diopters (D); the axial length was measured by immersion biometry, and the standard A-constant was used. Surgery included phacoemulsification, IOL (Acrysof SN60AT; Alcon) implantation within the capsular bag, and Descemet stripping automated endothelial keratoplasty using posterior lamella prepared with a 300-µm head microkeratome (Moria). The absolute prediction error (absolute difference between predicted and achieved refraction) was assessed 6 months after surgery. RESULTS: The mean power of the implanted IOL was 23.22 ± 2.90 D. The mean predicted and achieved refractions were -0.27 ± 0.26 D and -0.23 ± 0.73 D, respectively. The mean absolute prediction error was 0.59 ± 0.42 D (range, 0.05 to -1.52 D). The postoperative spherical equivalent fell within ±0.50 D, ±1.00 D, and ±2.00 D of the predicted refraction in 55.5%, 83.3%, and 100% of cases, respectively. Had the IOL power been calculated without adjusting the K readings, the mean absolute prediction error would have been significantly higher (0.86 ± 0.62 D; P = .04). CONCLUSIONS: In this study, in which posterior lamellae were prepared using a 300-µm head microkeratome, adjusting preoperative K readings by -1.19 D led to accurate IOL power calculation and highly predictable refractive error after cataract surgery combined with Descemet stripping automated endothelial keratoplasty.

Diagnosis of subclinical keratoconus using posterior elevation measured with 2 different methods.

PURPOSE: To compare the efficacy of posterior corneal elevation, measured by 2 methods, in discriminating subclinical keratoconus from normal corneas. METHODS: In 30 consecutive patients with subclinical keratoconus, and 37 candidates for refractive surgery, posterior corneal elevation was measured using Pentacam's rotating Scheimpflug camera (Oculus, Wetzlar, Germany) with the standard method [maximal elevation above the best fit sphere (BFS)] and with the enhanced-BFS (E-BFS) method (difference in elevation measured above the E-BFS and that measured above the BFS). Using cutoff points selected a priori (≥ 29 and ≥ 12 µm, respectively, for the standard and E-BFS methods) the sensitivity, specificity, and overall accuracy, determined through the area under the receiver operating characteristic curves, were assessed for each method and then compared. RESULTS: Mean posterior elevation values were statistically higher (P < 0.001) in corneas with subclinical keratoconus than in normal corneas, using either the standard (38 ± 15.9 µm vs. 20.3 ± 7.1 µm) or the E-BFS (15 ± 9.5 µm vs. 7.8 ± 5.5 µm) methods. Sensitivity and specificity rates were slightly higher with the standard method than with the E-BFS method (sensitivity, 73.3% vs. 60%; specificity, 86.5% vs. 83.8%), but neither difference was statistically significant (P > 0.05). The overall accuracy of the tests was similar (P = 0.19): the area under the curve was 0.80 for the standard and 0.72 for the E-BFS method. CONCLUSIONS: Posterior corneal elevation measured using either standard or E-BFS method has similar efficacy in discriminating corneas with subclinical keratoconus from normal corneas. As a single parameter, posterior elevation can be considered quite effective with either method, but it cannot be used alone to identify patients with subclinical keratoconus.

Wave-like opacities at the interface after descemet stripping automated endothelial keratoplasty.

PURPOSE: To describe a peculiar postoperative complication of Descemet stripping automated endothelial keratoplasty (DSAEK), characterized by wave-like opacities at the donor-recipient interface. METHODS: Wave-like opacities at the interface were observed a few days after surgery, in 1 eye of 2 patients who had undergone uneventful DSAEK for Fuchs endothelial dystrophy. DSAEK was performed using microkeratome-prepared lamellar grafts obtained from organ culture-preserved corneas. In the recipient, the 8.50-mm graft was inserted using a pull-through technique. Postoperative follow-up was 12 months in case 1 and 6 months in case 2. RESULTS: The wave-like opacities were whitish and involved the central cornea in both cases; in case 2, they were associated with hyperreflective dots. Despite intensive topical therapy with dexamethasone 0.2%, the opacities at the interface persisted during follow-up. However, visual acuity progressively improved; at last examination, uncorrected and corrected distance visual acuity were, respectively, 20/40 and 20/25 in case 1 and 20/30 and 20/20 in case 2. Optical coherence tomography showed that the interface reflectivity was slightly higher than it was in DSAEK cases without opacities. The central thickness of the whole cornea and the lamella were 563 and 93 µm in case 1 and 603 and 140 µm in case 2. Postoperative endothelial cell loss was 37% in case 1 and 24% in case 2. CONCLUSIONS: Wave-like opacities at the donor-recipient interface are a rare complication of DSAEK surgery of unclear origin. Although interface opacities involve the central cornea and persist after surgery, good postoperative visual recovery can be achieved.

In vitro susceptibility to different topical ophthalmic antibiotics of bacterial isolates from patients with conjunctivitis.

PURPOSE: To test in vitro the susceptibility to different commercially-available topical antibiotics of isolates from patients with conjunctivitis, evaluated at the Microbiology Service of Turin Ophthalmic Hospital between January 2005-February 2007. METHODS: Bacterial isolates were cultured using both liquid and solid media. The four most frequent isolates were analyzed and their in vitro susceptibility to levofloxacin, ofloxacin, norfloxacin, lomefloxacin, tobramycin, netilmycin, ampicillin, and chloramphenicol was tested, using the Kirby-Bauer diffusion method and National Committee for Clinical Laboratory Standards (NCCLS) serum standards. RESULTS: The four most common bacteria isolates were: Staphylococcus aureus (27%), viridians Streptococci (22%), Staphylococcus epidermidis (16%) and Streptococcus pneumoniae (13%). The in vitro susceptibility to levofloxacin was highest (p<0.01) for all bacterial isolates. CONCLUSIONS: In vitro susceptibility tests showed that levofloxacin had the highest cumulative efficacy against bacterial isolates. Netilmycin showed the highest efficacy against staphylococcus aureus, the most common bacterial isolate in this study.

Corneal power after DSAEK using microkeratome-prepared tissues.

PURPOSE: To investigate changes of corneal power after descemet stripping automated endothelial keratoplasty (DSAEK). METHODS: Anterior, posterior, and true-net (anterior + posterior) power of post-DSAEK and contralateral transparent corneas were measured, using the Pentacam rotating Scheimpflug camera (Oculus Wetzlar, Germany), 6 months after surgery in 23 consecutive patients who had undergone unilateral DSAEK at the same medical center. Moreover, in each cornea, Pentacam pachimetry was measured at the vertex and at 3 mm from the vertex, to calculate corneal thickness increase (CTI). RESULTS: In post-DSAEK corneas, the anterior power on average decreased by -0.24 ± 0.61 diopters (D), the negative posterior power increased by -0.96 ± 0.42 D, and the true-net power decreased by -1.19 ± 0.74 D (range: +0.17 to -2.23 D). Differences vs. contralateral transparent corneas did not reach statistical significance for anterior (p = 0.09) but were significant (p < 0.001) for posterior and true-net corneal power. CTI at 3 mm from the vertex was statistically larger (p < 0.0001) in post-DSAEK corneas (mean values 0.27 ± 0.07 vs. 0.12 ± 0.05); CTI values showed a statistically significant (p < 0.05) correlation with negative posterior corneal power values in post-DSAEK (r = -0.55) and in contralateral corneas (r = -0.67). CONCLUSIONS: In comparison with contralateral corneas, post-DSAEK corneas show a moderate reduction of the true-net corneal power measured by Pentacam. Knowledge of true-net corneal power changes might be useful in adjusting K values and calculating intraocular lens power, in eyes scheduled for DSAEK combined with intraocular lens implantation/exchange.

Phacoemulsification and customized toric intraocular lens implantation in eyes with cataract and high astigmatism after penetrating keratoplasty.

UNLABELLED: Phacoemulsification and implantation of a hydrophilic acrylic toric intraocular lens (IOL) (T-flex 623T) with customized cylindrical power was performed in 1 eye in 3 consecutive patients with cataract and high postkeratoplasty astigmatism (range 6.75 to 8.75 diopters [D]). Twelve months postoperatively, the uncorrected distance visual acuity improved from 20/200 to 20/30 in Case 1, from 20/400 to 20/40 in Case 2, and from 20/200 to 20/25 in Case 3 and the corrected distance visual acuity was 20/25 or better in all 3 eyes. The spheroequivalent was within ± 0.50 D of the intended value and the refractive astigmatism was less than 1.00 D. The corneal grafts were transparent, and the endothelial cell loss range was 6% to 12%. Rotation of the toric IOL was less than 5 degrees. The toric IOL with customized cylindrical power provided good postoperative rotational stability and very satisfactory postoperative visual recovery. This type of toric IOL is appropriate to correct high postkeratoplasty astigmatism in eyes operated on for cataract. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Long-term endothelial cell loss after traumatic dislocation and repositioning of Artisan phakic IOL.

PURPOSE: To evaluate long-term endothelial cell loss after traumatic dislocation and repositioning of an Artisan phakic intraocular lens (PIOL). METHODS: Traumatic PIOL dislocation occurred in the patient's left eye 4 months after uneventful implantation for unilateral congenital myopia. Using the Konan semi-automated analysis method, endothelial cell density was measured preoperatively, before Artisan repositioning, and 1, 2, and 4 years after primary implantation. RESULTS: Endothelial cell density was 2770 cells/mm2 preoperatively and 2634 cells/mm2 before Artisan repositioning. After successful repositioning, endothelial cell density progressively decreased--1, 2, and 4 years from primary implantation, endothelial cell density was 2582, 2524, and 2538 cells/mm2, respectively, corresponding to losses of 6.8%, 8.9%, and 8.4%, respectively. CONCLUSIONS: Progressive and long-term endothelial loss after traumatic dislocation and repositioning of the Artisan PIOL may be comparable to that reported after uneventful implantation.

Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus.

PURPOSE: To estimate the sensitivity and specificity of posterior elevation in discriminating keratoconus and subclinical keratoconus from normal corneas. DESIGN: Prospective case-control study. PARTICIPANTS: Seventy-five patients with keratoconus, 25 with subclinical keratoconus, and 64 refractive surgery candidates with normal corneas. METHODS: In one eye of each patient, posterior corneal elevation was measured in the central 5 mm using the Pentacam rotating Scheimpflug camera (Oculus, Wetzlar, Germany). Posterior corneal elevation in keratoconus and subclinical keratoconus were compared with that in normal corneas in separate analyses. Receiver operating characteristic (ROC) curves were used to determine the test's overall predictive accuracy (area under the curve) and to identify optimal posterior corneal elevation cutoff points to maximize sensitivity and specificity in discriminating keratoconus and subclinical keratoconus from normal corneas. Logistic regression was used to support cutoff points identified through ROC curve analysis, and to check for model validity; model goodness-of-fit was estimated using r(2), and its internal validation was by bootstrapping analysis. MAIN OUTCOME MEASURES: Posterior corneal elevation in keratoconus, subclinical keratoconus, and normal corneas. RESULTS: Mean posterior corneal elevation was statistically higher in keratoconus (100.7+/-49.2 microm; P<0.001), and subclinical keratoconus (39.9+/-15.0 microm; P = 0.01) versus normal corneas (19.8+/-6.37 microm). ROC curve analyses showed high overall predictive accuracy of posterior elevation for both keratoconus and subclinical keratoconus (area under the curve 0.99 and 0.93, respectively). Optimal cutoff points were 35 microm for keratoconus and 29 microm for subclinical keratoconus. These values were associated with sensitivity and specificity of 97.3% and 96.9%, respectively, for keratoconus, and 68% and 90.8% for subclinical keratoconus. Similar cutoff points were obtained with logistic regression analysis (38 microm for keratoconus and 32 microm for subclinical keratoconus). The models showed good fit to the data, including after internal validation. CONCLUSIONS: Posterior corneal elevation very effectively discriminates keratoconus from normal corneas. Its efficacy is lower for subclinical keratoconus, and thus data concerning posterior elevation should not be used alone to stratify patients with this condition.

Reproducibility and repeatability of central corneal thickness measurement in keratoconus using the rotating Scheimpflug camera and ultrasound pachymetry.

PURPOSE: To assess repeatability, reproducibility, and agreement of rotating Scheimpflug camera (Pentacam Oculus, Wetzlar, Germany) and ultrasound pachymetry in measuring central thickness of keratoconic corneas. DESIGN: Method-comparison study. METHODS: In 33 patients with keratoconus (one eye per patient), two examiners each used both pachymetric methods to measure central corneal thickness (CCT); in the same session, measurements then were repeated by examiner 1 (A.M.). The difference between two examiners, and between first and second measurements by examiner 1, with both methods and the difference between the two pachymetric methods in measuring central thickness of keratoconic corneas were noted. RESULTS: With the rotating Scheimpflug camera, interexaminer correlation was higher (intra-class correlation coefficient [ICC], 0.98 vs 0.76) and inter-examiner variability was lower (95% limits of agreement [95% LoA], -14.8 to 13.8 microm vs -18.0 to +49.5 microm) than with ultrasound pachymetry. Both methods showed close first- to second-measurement correlation (ICC, > 90), but the rotating Scheimpflug camera had lower variability (95% LoA, -14.5 to 14.2 microm vs -27.4 to 26.0 microm). Mean CCT was 478.9 +/- 34.6 microm with the rotating Scheimpflug camera and 486.6 +/- 30 microm with ultrasound pachymetry. Although the mean difference was small (-7.8 microm), the 95% LoA (-43.8 to 28.2 microm) showed that the difference between the two methods can be considerable. CONCLUSIONS: In keratoconic corneas, the rotating Scheimpflug camera provides measurements of central thickness that are more reproducible and repeatable than those obtained with ultrasound pachymetry. The rotating Scheimpflug camera seems to be suitable for disease staging and follow-up, when corneal thickness measurements may be repeated over time by different examiners.