Color LED reflection topography: validation of equivalent keratometry reading for IOL power calculation in eyes with previous corneal myopic refractive surgery.

PURPOSE: To compare the accuracy of the equivalent keratometry reading (EKR) from a color LED corneal topographer (Cassini) with that of other no-history formulas for intraocular lens (IOL) power calculation in eyes with previous myopic excimer laser surgery. SETTING: Centro de Oftalmología Barraquer, Barcelona, Spain. DESIGN: Retrospective case series. METHODS: The refractive outcomes of the Cassini EKR entered into the Haigis formula were compared with those of the Barrett True-K, Haigis-L, and Shammas-PL formulas and the Triple-S method combined with the Haigis formula. Optimized lens constants for virgin eyes were used. The mean prediction error (PE), the median absolute error (MedAE), and the percentage of eyes with a PE within ±0.25 diopter (D), ±0.50 D, ±0.75 D, and ±1.00 D were calculated. RESULTS: The study comprised 37 patients (37 eyes). The Haigis-L, Shammas-PL, and Barrett True-K no-history methods produced a myopic mean PE that was significantly different from zero (P < .001, P < .001 and P = .004, respectively), whereas the mean PEs of Cassini EKR and the Triple-S combined with the Haigis formula were not different from zero (P > .05). Repeated-measures analysis of variance disclosed a significant difference among the PE of all methods (P < .0001). The MedAE of the Cassini EKR, Barrett True-K, Haigis-L, Shammas-PL, and Triple-S was, respectively, 0.34 D, 0.34 D, 0.49 D, 0.48 D, and 0.31 D (P = .0026). CONCLUSIONS: The performance of the combination of standard Haigis formula with Cassini EKR was comparable to other no-history formulas in eyes with previous myopic excimer laser surgery.

Intraocular lens power calculation in virgin eyes: Accuracy of the Barrett Universal II formula and a Ray tracing software.

PURPOSE: To compare the accuracy of Sirius ray tracing software with the Barrett Universal II formula for intraocular lens power prediction in virgin eyes. METHODS: Retrospective case series including 86 eyes that have undergone uneventful cataract surgery with SN60WF implantation. The median absolute error, mean prediction error, variance, and the percentage of eyes within ± 0.25 D, ± 0.50 D, ± 0.75 D, and ± 1.00 D of the prediction error in refraction were calculated. The correlation of prediction error with different baseline parameters was investigated. RESULTS: No differences were found between the median absolute error of the Barrett Universal II formula (0.226 D) and the ray tracing software with different intraocular lens centerings; apex (0.331 D), limbus (0.345 D), and pupil (0.342 D) (p = 0.084). The variance, from lowest to highest, was the Barrett Universal II (0.144 D2), ray tracing-limbus (0.285 D2), ray tracing-pupil (0.285 D2), and ray tracing-apex (0.287 D2) (p = 0.027). The Barrett Universal II formula showed a higher percentage of eyes within ± 0.25 D (56.98%), ± 0.50 D (82.56%), and ± 0.75 D (93.02%) compared to ray tracing software (p < 0.01). A significant correlation between the prediction error of the Barrett Universal II formula and corneal diameter (r = 0.322, p = 0.002) and pupil diameter (r = 0.230, p = 0.033) was found. Also, a positive correlation between the prediction error of Sirius ray tracing and axial length (p < 0.001) and pupil diameter (p = 0.01) was found. CONCLUSION: There is a trend of the Barrett Universal II formula to be more accurate than Sirius ray tracing software for intraocular lens power calculation in virgin eyes. This should be confirmed in future prospective comparative studies.

Impact of contact lens wear on epithelial alterations in keratoconus

PURPOSE: The purpose of this study was to characterize the central epithelial thickness (CET) of penetrating keratoplasty corneal specimens obtained from patients with keratoconus (KC) and correlate the histological patterns with their clinical history. METHODS: Ex vivo histological imaging was performed to measure CET and total corneal thickness (TCT) in 56 patients with KC. Microscopic slides from penetrating keratoplasty corneal specimens, stained with hematoxylin and eosin were evaluated using bright field microscopy. CET and TCT were measured, and morphological features were studied. Clinical history regarding duration of KC prior to surgery and length of and tolerance to contact lens wear were compared and analyzed. RESULTS: The microscopic slides of all patients available for follow up (n = 48) were analyzed and CET and TCT were measured. The histological evaluation revealed 3 distinctive epithelial patterns. Pattern 1 with central hypertrophic and hydropic changes (n = 19) measured 70.89 ± 25.88 Mum in CET and 308.63 ± 100.74 Mum in TCT; Pattern 2 (n = 14) had not changed, similar to normal epithelium CET and TCT measuring 36.5 ± 7.02 Mum and 260.14 ± 87.93 Mum respectively. Pattern 3 (n = 15) demonstrated thinner central epithelium characterized by atrophy and focal hydropic changes measuring 19.93 ± 4.60 Mum and 268.00 ± 79.39 Mum in CET and TCT respectively (all p < 0.0001). The presence of Pattern 2 characterized by similar to normal CET was correlated with the duration of the condition (R = 0.600, p = 0.030). There was a significant difference in the length of CL wear comparing those with patterns 1 and 2 versus 3 (least no. of CL years) (p = 0.05 and p = 0.33 respectivelly). CONCLUSIONS: Patients with advanced disease have various central corneal epithelial changes detected with histology. Although each central epithelial pattern type was distinctive comparing the 3 patterns, there was no correlation with years of CL wear but only with the duration of the condition

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Impact of contact lens wear on epithelial alterations in keratoconus.

PURPOSE: The purpose of this study was to characterize the central epithelial thickness (CET) of penetrating keratoplasty corneal specimens obtained from patients with keratoconus (KC) and correlate the histological patterns with their clinical history. METHODS: Ex vivo histological imaging was performed to measure CET and total corneal thickness (TCT) in 56 patients with KC. Microscopic slides from penetrating keratoplasty corneal specimens, stained with hematoxylin and eosin were evaluated using bright field microscopy. CET and TCT were measured, and morphological features were studied. Clinical history regarding duration of KC prior to surgery and length of and tolerance to contact lens wear were compared and analyzed. RESULTS: The microscopic slides of all patients available for follow up (n=48) were analyzed and CET and TCT were measured. The histological evaluation revealed 3 distinctive epithelial patterns. Pattern 1 with central hypertrophic and hydropic changes (n=19) measured 70.89±25.88µm in CET and 308.63±100.74µm in TCT; Pattern 2 (n=14) had not changed, similar to normal epithelium CET and TCT measuring 36.5±7.02µm and 260.14±87.93µm respectively. Pattern 3 (n=15) demonstrated thinner central epithelium characterized by atrophy and focal hydropic changes measuring 19.93±4.60µm and 268.00±79.39µm in CET and TCT respectively (all p<0.0001). The presence of Pattern 2 characterized by similar to normal CET was correlated with the duration of the condition (R=0.600, p=0.030). There was a significant difference in the length of CL wear comparing those with patterns 1 and 2 versus 3 (least no. of CL years) (p=0.05 and p=0.33 respectivelly). CONCLUSIONS: Patients with advanced disease have various central corneal epithelial changes detected with histology. Although each central epithelial pattern type was distinctive comparing the 3 patterns, there was no correlation with years of CL wear but only with the duration of the condition.

Long-term Results of Corneal Cross-linking for Terrien's Marginal Degeneration.

PURPOSE: To report the long-term clinical outcomes of a patient with Terrien's marginal degeneration who underwent successful peripheral corneal cross-linking (CXL) to arrest progression. METHODS: Clinical assessment included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), corneal topography, anterior segment optical coherence tomography, ultrasonic pachymetry, corneal hysteresis, and corneal resistance factor. Eccentric epithelium-off CXL was performed in both eyes after limbal conjunctival resection. Following the Dresden protocol, fluence irradiation was set at 5.4 J/cm2, using 3 mW/cm2 for a total exposure time of 30 minutes. RESULTS: Nine years of postoperative follow-up showed significant bilateral improvement in visual acuity, refraction, and corneal topography with no signs of progression of Terrien's marginal degeneration. In the right eye, UDVA improved from 0.05 to 0.3 decimal and CDVA from 0.8 to 1.2 decimal, cylinder was reduced from -14.00 to -3.00 diopters (D), simulated keratometry improved from 10.50 to 3.70 D, and the thinnest point on pachymetry remained almost unchanged (from 483 to 469 µm). In the left eye, UDVA improved from 0.1 to 0.2 decimal and CDVA remained unchanged at 1.2 decimal, cylinder was reduced from -6.00 to -2.75 D, simulated keratometry improved from 5.60 to 3.30 D, and the thinnest point on pachymetry remained stable at 486 µm. CONCLUSIONS: Eccentric peripheral CXL can be a safe, noninvasive alternative therapeutic approach for the management of Terrien's marginal degeneration with peripheral thinning. [J Refract Surg. 2018;34(6):424-429.].

Human lens capsule thickness as a function of age and location along the sagittal lens perimeter.

PURPOSE: To investigate the variation in the thickness of the human lens capsule along the lens perimeter, as well as its changes with age. METHODS: Altogether, 26 human donor lenses, aged 12 to 103 years, were histologically processed. Sagittal sections were stained for collagen with periodic acid-Schiff (PAS). Serial images of the lens border were taken with a photomicroscope and 25x objective. Capsular thickness was measured every 250 microm along the entire lens perimeter. RESULTS: All studied capsules were thicker anteriorly, continuously increasing with age from 11 to 15 microm in average at the anterior lens pole. Maximum thickness was located at the anterior midperiphery, increasing with age from 13.5 to 16 microm. In most cases, there was a local thinning at a pre-equatorial zone, recovering to approximately 7 microm at the equator. The latter value, as well as the minimal thickness at the posterior pole (mean 3.5 microm), did not change with age, whereas the average thickness at the posterior periphery decreased from 9 to 4 microm. CONCLUSIONS: The human lens capsule thickness is at its maximum at the anterior midperiphery, which appears to be located central to the zonular insertion. It increases with age, especially at the anterior pole, while the midperipheral zone stabilizes or slightly decreases after the seventh decade. The anterior zonular insertion is actually related to a local pre-equatorial thinning, which remains unchanged with age. There was no posterior peripheral thickening, except in a few younger patients, with a modest relative maximum roughly at the equator. From here, the posterior capsule becomes progressively thinner and also diminishes with age, except for the thinnest, but stable posterior pole.

Degeneraçao cerebelar subaguda paraneoplásica: relato de caso / Paraneoplastic subacute cerebellar degeneration: case report

Descrevemos caso de uma paciente de 40 anos com quadro de degeneraçao cerebelar subaguda paraneoplásica associada a tumor ovariano. Apresentamos breve revisao sobre as manifestaçoes clínicas e laboratoriais desta síndrome, enfatizando a importância do seu reconhecimento, o que possibilita muitas vezes a detecçao e tratamento precoce da doença primária