Tilt and decentration of intraocular lenses (IOL) may occur secondary to a complicated cataract surgery or following an uneventful phacoemulsification. Although up to 2–3° tilt and a 0.2–0.3 mm decentration are common and clinically unnoticed for any design of IOL, larger extent of tilt and decentration has a negative impact on the optical performance and subsequently, the patients’ satisfaction. This negative impact does not affect various types of IOLs equally. In this paper we review the methods of measuring IOL tilt and decentration and focus on the effect of IOL tilt and decentration on visual function, in particular visual acuity, dysphotopsia, and wavefront aberrations. Our review found that the methods to measure the IOL displacement have significantly evolved and the available studies have employed different methods in their measurement, while comparability of these methods is questionable. There has been no universal reference point and axis to measure the IOL displacement between different studies. A remarkably high variety and brands of IOLs are used in various studies and occasionally, opposite results are noticed when two different brands of a same design were compared against another IOL design in two studies. We conclude that 0.5 mm. The effect of IOL displacement on visual function is more pronounced in aberration correcting IOLs compared to spherical and standard non-aberration correcting aspherical IOLs and in multifocal versus monofocal IOLs. Internal coma has been frequently associated with IOL tilt and decentration, and this increases with pupil size. There is no correlation between spherical aberration and IOL tilt or decentration. Although IOL tilt produces significant impact on visual outcome in toric IOLs, these lenses are more sensitive to rotation compared to tilt.

https://www.mdpi.com/2411-5150/4/3/41/pdf

Effect of Intraocular Lens Tilt and Decentration on Visual Acuity, Dysphotopsia and Wavefront Aberrations.

Purpose To investigate the choriocapillaris in children with amblyopia, using optical coherence tomography angiography (OCT-A). Methods Patients with amblyopia and age-matched controls were prospectively imaged using OCT-A. On OCT-A, the choriocapillaris measures 30 μm starting 31 μm posterior to the retinal pigment epithelium. The section of choriocapillaris under superficial retinal vessels was excluded from analysis to avoid shadowing or projection artifacts. The main outcome measure was choriocapillaris vessel density. Secondary outcome measures were foveal macular thickness and parafoveal macular thickness. Results A total of 20 eyes of 16 patients with amblyopia and 25 eyes of 25 controls were included. Mean age of amblyopic subjects was 7.6 ± 3.6 years; of controls, 9.3 ± 2.2 years ( P  = 0.10). Mean refractive error of subjects was 4.3 ± 6.2 D; of controls, 0.0 ± 1.6 D ( P  = 0.004). Mean choriocapillaris vessel density was 74.8 ± 5.8 in the amblyopic group and 71.1 ± 3.6 in the control group, which was significant even after adjusting for age and refractive error ( P  = 0.012). There was no difference between groups in foveal macular thickness or parafoveal macular thickness; however, outer parafoveal macular thickness (the inner boundary of the inner nuclear layer to the retinal pigment epithelium outer boundary) was significantly greater in amblyopic eyes than in control eyes, even after adjusting for age and refractive error (203 ± 11 μm and 189 ± 12 μm, resp. [ P  = 0.014]). Conclusions In our study cohort, amblyopic eyes were found to have increased choriocapillaris vessel density as well as a greater outer parafoveal macular thickness, which may be due to alterations in outer retinal maturation.

Increased choriocapillaris vessel density in amblyopic children: a case-control study.

To compare the long-term decentration and tilt in two multifocal intraocular lenses (MfIOLs) with an OPD-Scan III aberrometer. Eighty cataract patients who underwent uneventful MfIOL implantation (42 with AcrySof® IQ ReSTOR® SN6AD1 and 38 with AMO Tecnis® ZMB00) were enrolled. At 1 year after surgery, a postoperative visual acuity evaluation included the measurement of uncorrected distance visual acuity, corrected distance visual acuity, distance-corrected near visual acuity, and distance-corrected intermediate visual acuity. OPD-Scan III aberrometer was used to collect the decentration, tilt, and high-order aberration (HOA) data. Significance was tested with Student’s t test, Mann–Whitney U test, paired t test, and χ2 test The average intraocular tilt was lower in the SN6AD1 group than in the ZMB00 group, whereas the average decentration of the two groups did not differ significantly. The mean total ocular HOAs, ocular trefoil, total internal HOAs, and spherical aberrations were significantly lower in the SN6AD1 group than in the ZMB00 group. In both the SN6AD1 and ZMB00 groups, the intraocular tilt was directly proportional to the total ocular HOAs, coma, and spherical aberration. However, there was no significant correlation between decentration and any type of HOA in SN6AD1 group, whereas decentration correlated positively with total ocular HOAs, coma, and spherical aberration in ZMB00 group. Both MfIOLs significantly improve the visual acuity of the patients. However, tilt was lower in the SN6AD1 group than in the ZMB00 group 1 year after surgery, which provide fewer HOAs and better visual quality.

/pdf/comparison-of-long-term-decentration-and-tilt-in-two-types-2wnus7n1ah.pdf

Comparison of long-term decentration and tilt in two types of multifocal intraocular lenses with OPD-Scan III aberrometer.

Purpose To investigate potential differences in the retinal nerve fiber layer (RNFL) thickness, macular thickness and foveal thickness between amblyopic eyes and normal fellow eyes on spectral domain optical coherence tomography (SD-OCT). Methods A cross-sectional study of patients ≥10 years of age with unilateral amblyopia resulting from an anisometropic, strabismic or deprivative cause. Comprehensive ophthalmic examination was completed and the retinal structures of both eyes were measured using SD-OCT. We compared the measurements obtained between the amblyopic eye and the fellow normal eye in each subject. Results Twenty-six unilateral amblyopia patients with a mean age of 29.92 ± 14.19 years old participated in the study, of which 17 (65.4%) were classified as anisometropic, 7 (26.9%) as strabismic, and 2 (7.7%) as deprivative. For the amblyopic eye and fellow normal eye, respectively, the mean RNFL thickness was 95.87 ± 14.56 μm and 97.87 ± 14.56 μm (P = 0.628), the mean macular thickness was 270.87 ± 14.43 μm and 275.60 ± 14.43 μm (P = 0.251) and the mean foveal thickness was 250.59 ± 27.82 μm and 242.91 ± 27.82 μm (P = 0.332). SD-OCT assessments revealed no statistically significant differences between both eyes. Conclusions Using SD-OCT, there were no significant changes in the retinal structure of amblyopic eyes. Therefore, amblyopia does not seem to have a profound structural effect on the retinal nerve fiber layer, the macula, or the fovea.

Evaluation of retinal structure in unilateral amblyopia using spectral domain optical coherence tomography.

Secondary intraocular lens implantation for pediatric aphakia

Purpose 
To evaluate the long-term outcomes of ciliary sulcus versus capsular bag fixation of intraocular lenses (IOLs) in children after pediatric cataract surgery.


Methods 
IOL was implanted in the ciliary sulcus in 21 eyes of 14 children, and in the capsular bag in 19 eyes of 12 children for the treatment of pediatric cataract in an institutional setting. Ultrasound biomicroscopy (UBM) was performed. Main outcome measures included IOL decentration, IOL tilt, anterior chamber depth (ACD), angle-opening distance at 500 μm (AOD500), trabecular-iris angle (TIA), best-corrected visual acuity (BCVA), intraocular pressure (IOP), and incidence of postoperative complications.


Results 
The mean follow-up period was 6.81 ± 1.82 years. Comparing to the capsular bag fixation group, the ciliary sulcus fixation group had higher vertical IOL decentration, horizontal IOL tilt, and vertical IOL tilt (p = 0.02, 0.01,0.01, respectively), higher incidence of iris-IOL contact and peripheral anterior synechia (p = 0.001, 0.03, respectively), smaller ACD, AOD500, and TIA (p = 0.02, 0.03, 0.04, respectively), higher mean IOP (17.10 ±6.06 mmHg vs.14.15± 4.74 mmHg, p = 0.01), and higher incidence of secondary glaucoma (28.57% vs. 10.53%, p = 0.007).There was no significant difference between the two groups with regard to the BCVA, refractive errors, incidence of myopic shift, nystagmus, strabismus, and visual axis opacity.


Conclusions 
Ciliary sulcus fixation of IOLs in pediatric eyes may increase IOL malposition and crowding of the anterior segment, and may associate with a higher risk of secondary glaucoma compared to capsular bag fixation of IOLs.

/pdf/long-term-outcomes-of-ciliary-sulcus-versus-capsular-bag-1pmvh1z2ol.pdf

Long-term outcomes of ciliary sulcus versus capsular bag fixation of intraocular lenses in children: An ultrasound biomicroscopy study.

Purpose To use highly precise spectral-domain optical coherence tomography (SD-OCT) to determine whether there were structural abnormalities in the layers of different regions of the fovea in children with anisometropic amblyopia. Methods Eighteen children (mean age 7.8 years old; range 5-11 years) with unilateral anisometropic amblyopia and 18 age-matched control subjects participated. Foveal thickness was measured with an enhanced depth imaging system, SD-OCT and segmented into layers using custom developed software. The thickness of each layer of the fovea was compared among amblyopic eyes, fellow eyes and control eyes with optical magnification correction for axial length and statistical correction for age and sex. Results The total thickness and each intra-ocular layer of the central fovea were the same for each group. However, the amblyopic eyes were significantly thicker than the normal control eyes in 2 of 4 quadrants of the peripheral retina. Exploring intra-retinal layers in these two quadrants, the nasal nerve fiber layer (NFL) and inferior inner nuclear layer (INL)were significantly thicker in amblyopic eyes than in control eyes (p = 0.01 and 0.012, respectively, by ANCOVA). Conclusion The SD-OCT data revealed marginal differences in some foveal layers at peripheral locations and indicated that structural differences might exist between individuals with amblyopia and visually normal control subjects. However, the differences were scattered and represented no identifiable pattern. More studies with large samples and precise locations of the retinal layers must be performed to extend the present results.

/pdf/thickness-of-retinal-layers-in-the-foveas-of-children-with-328cy6437i.pdf

He-ming Li

Papers

Long-term outcomes of ciliary sulcus versus capsular bag fixation of intraocular lenses in children: An ultrasound biomicroscopy study.

Thickness of retinal layers in the foveas of children with anisometropic amblyopia.