Correlation of Intraoperative Optical Coherence Tomography of Crystalline Lens Diameter, Thickness, and Volume with Biometry and Age.

PURPOSE: To characterize crystalline lens dimensions derived from in vivo spectral-domain optical coherence tomography (SD-OCT) and identify associations among these parameters, ocular biometry, and age. METHODS: In this retrospective study, lens thickness (LT), lens diameter (LD), and lens volume (LV) were measured intraoperatively using SD-OCT in 293 eyes undergoing lens surgery. Correlations among LT, LD, LV, age, axial length (AL), and anterior chamber depth (ACD) were analyzed. Multiple regression analysis was performed to determine whether a combination of biometric data could predict LD and LV. RESULTS: Wide variations were observed in LT (3.6-5.7 mm), LD (7.5-11.9 mm), and LV (119.9-312.4 mm3) of aging eyes. Correlations among the 3 lens dimensions were statistically significant (LV-LT: r = 0.785; P < .001; LV-LD: r = 0.696; P < .001; and LT-LD: r = 0.121; P = .039). With age, the correlation coefficients of LT, LD, and LV were 0.526, 0.326, and 0.573, respectively (P < .001). Although there was significant correlation of AL with LT (r = -0.137; P = .002) and LD (r = 0.268; P < .001), it was not significant with LV (r = 0.084; P = .15). Subgroup analysis revealed that 19.8% of long eyes had LD >1 standard deviation (SD) above and that 5.2% had LD <1 SD below the mean LD. CONCLUSIONS: Dimensions of the aging lens vary considerably and are most accurately characterized by direct measurement of LT, LD, and LV, rather than making assumptions based on AL. These findings challenge historically proposed relationships between LD and AL and represent a normative dataset of contemporary geometric features of the aging lens, possibly aiding in surgical decision making and future developments in lens surgery.

Static and Dynamic Factors Associated With Extended Depth of Focus in Monofocal Intraocular Lenses.

PURPOSE: To analyze factors affecting depth of focus (DOF) and near vision functionality in eyes implanted with aspheric monofocal intraocular lenses (IOLs). METHODS: This prospective study included 111 eyes of 74 patients that underwent phacoemulsification with monofocal IOL implantation. Ninety-one normal eyes were randomized to receive aberration-free (n = 30) or negative-spherical aberration (SA) IOLs (n = 61). Twenty post-hyperopic femto-LASIK eyes received aberration-free IOLs. Corneal higher-order aberrations (SA, coma, trefoil, and corneal asphericity) for a 6 mm pupil were measured by Scheimpflug tomography. Ray-tracing metrics (visual Strehl optical transfer function [VSOTF], effective range of focus [EROF], sphere shift [SS], EROF-SS), pupil size measurements at far and near, and ocular and corneal SA were obtained using ray-tracing aberrometry. Distance-corrected near visual acuity (DCNVA) and subjective defocus curves up to ±4.0 diopters were evaluated. RESULTS: Multivariable logistic regression found corneal profile and IOL type to be determinants of extended DOF with monofocal IOLs. The aberration-free IOL group showed significantly better DCNVA and higher total SA than the negative-SA group. Post-hyperopic LASIK eyes showed significantly better DCNVA; higher negative SA, coma, and Q value (P < .05), and smaller pupil size (P = .05) than normal eyes implanted with aberration-free IOLs. CONCLUSION: Corneal profile and type of IOL implanted were the most important factors influencing near vision functionality with aspheric monofocal IOLs. Higher positive SA in the aberration-free group potentially led to better DCNVA than the negative-SA group in normal eyes. Hyperprolate corneas had better DOF curves and DCNVA than normal corneas. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Objective assessment of optical quality in dry eye disease using a double-pass imaging system.

PURPOSE: To assess optical quality dynamics using a double-pass (DP) system in patients with dry eye disease (DED). METHODS: Seventy-six eyes with DED and 44 control subjects were enrolled in this study. Each patient underwent ocular surface evaluation including fluorescein corneal staining and Schirmer's II test. Ocular Surface Disease Index (OSDI) questionnaire was used to assess subjective symptoms. Optical quality dynamics and tear film instability was analyzed using a DP system (HD AnalyzerTM, Visiometrics, Spain). Mean objective scatter index (OSI), maximum and minimum OSI, difference between maximum and minimum OSI (ΔOSI) were recorded with 40 consecutive scans over 20 s. RESULTS: The DED group had pronounced impairment of optical quality compared to the control group. Mean OSI (4.29±4.07), minimum (3.22±3.51) and maximum (5.72±4.52) OSI, ΔOSI (2.50±1.96), OSDI score (36.94±16.55), and fluorescein corneal staining (0.79±0.96) were statistically significantly higher than controls (p<0.05). Schirmer's II test was statistically significantly lower in the DED group compared to controls (10.08±7.85, 26.41±6.75, respectively; p<0.001). Three patterns of dynamic changes of OSI were proposed: ladder (continuous increase of OSI), seesaw (instability of OSI without improvement after blinking), and plateau (steady-high OSI). The ladder group showed the highest value of maximum OSI (6.93±4.13; p=0.03) and ΔOSI (3.76±2.08; p<0.001). CONCLUSION: DP imaging system provides an objective measurement of the visual quality in DED. Tear film instability may be assessed by dynamic changes of OSI over 20 s. In particular, the highest OSI values were observed in the ladder pattern group.

Lens anatomy parameters with intraoperative spectral-domain optical coherence tomography in cataractous eyes.

PURPOSE: To study correlations of crystalline lens anatomy and position parameters obtained using intraoperative spectral-domain (SD) optical coherence tomography (OCT) in cataract patients. METHODS: This retrospective study evaluated biometry data from 600 eyes of 399 cataract patients (mean age: 69±8.4 years) using intraoperative anterior segment SD-OCT during femtosecond laser-assisted cataract surgery. Lens anatomy and position parameters (anterior chamber depth [ACD] - center of the anterior cornea to the anterior lens capsule, lens thickness [LT] - distance between anterior and posterior lens capsules, and lens meridian position [LMP] - distance from center of the anterior cornea to intersection of the anterior and posterior lens) obtained with intraoperative SD-OCT, were correlated among themselves and with noncontact axial length (AL). Equatorial plane position (EPP) (distance between the plane of the lens equator and anterior capsule) was also studied. Pearson's coefficients (r-values) were determined for all correlation pairs. RESULTS: There was a moderate correlation between AL and ACD (r=0.451; P<0.001). LMP was found to correlate strongly with ACD (r=0.77; P<0.001) but very weakly with AL (r=0.089; P=0.04). There was a moderately strong inverse correlation between LT and ACD (r=-0.586; P<0.001) but the correlation between LT and AL and LT and LMP was found to be weak (r=-0.155; P<0.001 and r=-0.121, P=0.003, respectively). Correlation of the ratio of EPP/LT and LT was weakly positive (r=0.267; P<0.001). CONCLUSION: LMP correlated strongly with ACD but only minimally with AL. LT correlated fairly strongly with ACD but only minimally with LMP. This should stimulate additional research into the relationships among ocular and crystalline lens anatomy and IOL position after cataract surgery.