Effect of spherical aberration on visual acuity and depth of focus in pseudophakic eyes.

PURPOSE: To assess the performance of 4 intraocular lenses (IOLs) in various spherical aberration (SA) conditions, using the VAO adaptive optics simulator. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas. DESIGN: Prospective case series. METHODS: Distance-corrected visual acuities at distance (CDVA), intermediate (DCIVA), and near (DCNVA) were measured in 42 dilated pseudophakic eyes at baseline and with ocular SA ranging from -0.4 to +0.4 µm in increments of 0.2 µm (6.0-mm pupil). 4 IOL types were assessed: monofocal IOLs with zero-SA, enhanced-monofocal, extended depth-of-focus (EDOF), and continuous range-of-vision. RESULTS: Compared with SA = 0 µm, significant changes (all P < .05) were: (1) zero-SA monofocal IOLs' DCNVA at high contrast improved by 0.13 logMAR with SA = -0.4 µm and worsened by 0.09 and 0.10 logMAR with SA = +0.2 and +0.4 µm, respectively. DCNVA at low contrast worsened by 0.09 logMAR with SA = +0.4 µm; and (2) with SA = -0.4 µm, the enhanced monofocal IOL lost 0.06 logMAR of CDVA at high contrast and gained 0.09 logMAR of DCNVA at low contrast. There were no significant changes from SA = 0 µm for EDOF and continuous range-of-vision IOLs. CONCLUSIONS: Zero-SA and EDOF IOLs were the most and least sensitive to SA modulation, respectively. In perfect optical systems where all the optical elements are aligned, induction of targeted amounts of negative SA improved the depth of focus of some IOL types. No benefit was found with positive SA.

Performance of IOL calculation formulas that use measured posterior corneal power in eyes following myopic laser vision correction.

PURPOSE: To compare the predictive accuracy of the biometer-embedded Barrett True-K TK and new total corneal power methods of intraocular lens (IOL) power calculation in eyes with prior laser vision correction (LVC) for myopia. SETTING: Academic clinical practice. DESIGN: Retrospective case series. METHODS: IOL power formulas were assessed using measurements from a swept-source optical coherence biometer. Refractive prediction errors were calculated for the Barrett True-K TK, EVO 2.0, Pearl-DGS, and HofferQST, which use both anterior and posterior corneal curvature measurements. These were compared with the Shammas, Haigis-L, Barrett True-K No History (NH), optical coherence tomography, and 4-formula average (AVG-4) on the ASCRS postrefractive calculator, and to the Holladay 1 and 2 with non linear axial length regressions (H1- and H2-NLR). RESULTS: The study comprised 85 eyes from 85 patients. Only the Barrett True-K TK and EVO 2.0 had mean numerical errors that were not significantly different from 0. The EVO 2.0, Barrett True-K TK, Pearl-DGS, AVG-4, H2-NLR, and Barrett True-K NH were selected for further pairwise analysis. The Barrett True-K TK and EVO 2.0 demonstrated smaller root-mean-square absolute error compared with the Pearl-DGS, and the Barrett True-K TK also had a smaller mean absolute error than the Pearl-DGS. CONCLUSIONS: The Barrett True-K TK and EVO 2.0 formulas had comparable performance to existing formulas in eyes with prior myopic LVC.

Comparison of Keratoconus Specific to Standard IOL Formulas in Patients With Keratoconus Undergoing Cataract Surgery.

PURPOSE: To assess the performance of multiple intraocular lens (IOL) formulas in eyes with keratoconus. METHODS: Eyes with stable keratoconus scheduled for cataract surgery with biometry measurements on the Lenstar LS900 (Haag-Streit) were included. Prediction errors were calculated using 11 different formulas, including two with keratoconus modifiers. Primary outcomes compared standard deviations, mean and median numerical errors, and percentage of eyes within diopter (D) ranges across all eyes with subgroup analysis according to anterior keratometric values. RESULTS: Sixty-eight eyes from 44 patients were identified. In eyes with keratometric values less than 50.00 D, prediction error standard deviations ranged from 0.680 to 0.857 D. Percentages of eyes within ±0.50 D of target ranged from 57.89% to 73.68% with no statistical differences among formulas. In eyes with a keratometric value of more than 50.00 D, prediction error standard deviations ranged from 1.849 to 2.349 D and were not statistically different with heteroscedastic analysis; percentages of eyes within ±0.50 D of target ranged from 0% to 18.18% with no statistical differences among formulas. Only keratoconus-specific formulas (Barrett-KC and Kane-KC) and the Wang-Koch axial length adjustment version of SRK/T resulted in median numerical errors not significantly different than 0, regardless of keratometric values. CONCLUSIONS: In keratoconic eyes, IOL formulas are less accurate than in normal eyes and result in hyperopic refractive outcomes that increase with steeper keratometric values. Using keratoconus-specific formulas and the Wang-Koch axial length adjustment version of SRK/T for axial lengths of 25.2 mm or greater improved IOL power prediction accuracy compared to other formulas. [J Refract Surg. 2023;39(4):242-248.].

Efficacy of segmented axial length and artificial intelligence approaches to intraocular lens power calculation in short eyes.

PURPOSE: In short eyes, to compare the predictive accuracy of newer intraocular lens (IOL) power calculation formulas using traditional and segmented axial length (AL) measurements. SETTING: Cullen Eye Institute, Baylor College of Medicine, Houston, Texas and East Valley Ophthalmology, Mesa, Arizona. DESIGN: Multi-center retrospective case series. METHODS: Measurements from an optical biometer were collected in eyes with AL <22 mm. IOL power calculations were performed with 15 formulas using 2 AL values: (1) machine-reported traditional AL (Td-AL) and (2) segmented AL calculated with the Cooke-modified AL nomogram (CMAL). 1 AL method and 7 formulas were selected for pairwise analysis of mean absolute error (MAE) and root mean square absolute error (RMSAE). RESULTS: The study comprised 278 eyes. Compared with the Td-AL, the CMAL produced hyperopic shifts without differences in RMSAE. The ZEISS AI IOL Calculator (ZEISS AI), K6, Kane, Hill-RBF, Pearl-DGS, EVO, and Barrett Universal II (Barrett) formulas with Td-AL were compared pairwise. The ZEISS AI demonstrated smaller MAE and RMSAE than the Barrett, Pearl-DGS, and Kane. K6 had a smaller RMSAE than the Barrett formula. In 73 eyes with shallow anterior chamber depth, the ZEISS AI and Kane had a smaller RMSAE than the Barrett. CONCLUSIONS: ZEISS AI outperformed Barrett, Pearl-DGS, and Kane. The K6 formula outperformed some formulas in selected parameters. Across all formulas, use of a segmented AL did not improve refractive predictions.

Vision Impairment and Patient Activation among Medicare Beneficiaries.

PURPOSE: Low patient activation is associated with poor patient outcomes. People with vision impairment may have low patient activation as a result of communication and access barriers. We examined the association of patient activation with vision impairment. METHODS: Cross-sectional study using the 2016 Medicare Current Beneficiary Survey. Older Medicare beneficiaries, without dementia, who completed the topical patient activation questionnaire were included. The primary exposure was self-reported vision impairment (no vision impairment, a little vision impairment, a lot of vision impairment), and the secondary exposure was dual sensory impairment (no sensory impairment, vision impairment only, hearing impairment only, dual sensory impairment). Patient activation scores were categorized as low, moderate, or high based on their distribution around the mean. Multivariable-adjusted ordinal regression models examined the association of patient activation with vision impairment, and then with dual sensory impairment. RESULTS: In total, 6,683 participants were included. Those with a little vision impairment had 20% lower odds of higher patient activation (odds ratio [OR] = 0.80, 95% confidence interval [CI] = 0.71-0.90), and those with a lot of vision impairment had 26% lower odds of higher patient activation (OR = 0.74, 95% CI = 0.55-0.98). In the second model, having vision or hearing impairment only was associated with lower odds of higher activation than having no sensory impairment. Having dual sensory impairment was associated with even lower odds of higher activation. CONCLUSION: Older Medicare beneficiaries with sensory impairment may be a group to target to improve patient activation levels, which could potentially improve health outcomes and health care utilization patterns in this population.

Management of Anterior Stromal Necrosis After Polymethylmethacrylate ICRS: Explantation Versus Exchange With Corneal Allogenic Intrastromal Ring Segments.

PURPOSE: To evaluate management of keratoconic eyes with anterior stromal necrosis overlying the intracorneal ring segment (ICRS), by either ICRS explantation alone or exchange with corneal allogenic intrastromal ring segments (CAIRS). METHODS: Among 643 Intacs SK (Additional Technology, Inc) inserted at one institutional center, 16 eyes (15 patients) with overlying spontaneous anterior stromal necrosis were identified. Data included size of stromal defect and refractive and topographical findings before ICRS insertion, before anterior stromal necrosis, and 6 months after intervention. RESULTS: The 10-year incidence of anterior stromal necrosis after femtosecond laser-assisted ICRS insertion was 5.5%. Eight eyes underwent ICRS removal only and 8 eyes had ICRS exchanged with CAIRS. In the first group, CDVA worsened from 0.14 before melt to 0.28 logMAR after removal (P = .10), simulated keratometry (SimK) and maximum axial keratometry (Kmax) increased from 44.73 to 46.34 diopters (D) (P = .14) and from 49.23 to 52.26 D (P = .14), respectively, and coma worsened from 0.87 to 1.52 D (P = .02). In the CAIRS group, CDVA of 0.16 before melt improved to 0.11 logMAR postoperatively (P > .99), and topographic indices stabilized with SimK, Kmax, and coma mildly altering from 45.31 to 45.44 D (P > .99), from 49.25 to 49.64 D (P > .99) and from 0.87 to 0.81 D (P > .99), respectively. Whether the ICRS were explanted or exchanged, the visual and topographic mean values were better than those reported before ICRS implantation, whereas higher order aberrations in eyes without CAIRS regressed to levels before ICRS insertion. At the site of melt, thinnest residual stromal thickness averaged 327 µm with ICRS removal and 490 µm with CAIRS. Eyes with larger melt areas resulted in less optimal results with CAIRS implantation. CONCLUSIONS: Early experience in the management of anterior stromal necrosis by exchange of polymethylmethacrylate ICRS with CAIRS seems to avoid stromal thinning and confer better visual and topographic results, which were more pronounced with thicker segments. The benefit of CAIRS in large stromal melts needs to be investigated. [J Refract Surg. 2022;38(4):256-263.].

Epidemiology, etiology, and outcomes of out-of-hospital cardiac arrest in young patients in lebanon.

BACKGROUND: The burden of out-of-hospital cardiac arrest (OHCA) on different population segments in developing countries is not well studied. Previous studies from Lebanon report poor survival to hospital discharge (4.8%-5.5%). This study describes characteristics and outcomes of young OHCA victims in Beirut, Lebanon METHODS: This retrospective observational study included young patients (<35 years of age) with OHCA admitted to the emergency department (ED) of a tertiary care center in Lebanon over a 10-year period. RESULTS: Fifty-four patients with OHCA were identified. Most were males (74.1%, n = 40) and the mean age was 17.9 ± 10.9 years. The most common arrest location was home (44.4%, n = 24). The majority were witnessed (78.8%, n = 41) with 15.4% (n = 8) witnessed by emergency medical services (EMS). Prehospital cardiopulmonary resuscitation was done for 22 patients (41.5%) mostly by EMS (n = 19, 86.4%), 9.1% (n = 2) by a bystander, and 4.5% (n = 1) by a family member. Prehospital automated external defibrillator use was documented in 13% (n = 7) of cases. Most patients (n = 48, 88.9%) were resuscitated in the ED where the most common rhythm was asystole (55.6%, n = 30). Half of the patients (50%, n = 27) survived to hospital admission. Overall survival to hospital discharge was 16.7% (n = 9). Good neurologic outcome (cerebral performance category 1 or 2) was documented in seven patients (9.3%). CONCLUSION: Survival rate of young OHCA victims in Lebanon (16.7%) is higher than previously reported rates of OHCA in the overall population. Targeted community activities and medical oversight of EMS activities are needed to link EMS activities to clinical outcomes.