Posterior capsular opacification evaluation through contrast sensitivity defocus curves with two multifocal intraocular lenses of similar material.

PURPOSE: To assess the degree of posterior capsular opacification (PCO) and its influence on contrast sensitivity defocus curve (CSDC) after implantation of two trifocal intraocular lenses (IOLs), Alsafit (AT) and Liberty (L), during a 12-month follow-up. A secondary aim was to evaluate the Nd:YAG capsulotomy rate in a long time. METHODS: Data from 63 subjects, 34 implanted with AT and 29 with L, were retrospectively analyzed for this pilot study. In those eyes without capsulotomy during the first year (n = 58), CSDC at 3 and 12 months after surgery and PCO grading were measured, with additional answering of a visual function questionnaire (VF-14) and a question of general satisfaction. The period after surgery up to capsulotomy or last on-demand visit without Nd:YAG was recorded for survival analysis beyond the 12-month follow-up. RESULTS: Total area under CSDC (TAUC) between 3 and 12 months decreased from 2.96 to 1.71 for AT (p < 0.05) and from 2.73 to 2.21 (p > 0.05) for L. Of eyes, 51.6, 19.3, and 29% with AT were graded as level 0, 1, and 2 of PCO, while 85.1, 11.1, and 3.7% of eyes with L were graded as level 0, 1, and 2 (p < 0.05). PCO grading was correlated with a decrease of TAUC (ρ = - 0.27, p = 0.04). Median time to require capsulotomy was 22 months with AT and 30 months with L (p < 0.05). CONCLUSIONS: PCO decreases CSDC in patients with trifocal lenses. Despite using the same hydrophilic material, PCO grading and Nd:YAG capsulotomy rate was higher for AT than for L.

Clinical Analysis of Central Islands after Small Incision Lenticule Extraction (SMILE).

PURPOSE: To evaluate the incidence of central islands after 6-month follow-up of Small Incision Lenticule Extraction (SMILE) and to assess their role in safety and accuracy. METHODS: Analysis of the preoperative and postoperative corneal tomography, best spectacle refraction and corrected distance visual acuity of 82 subjects that underwent SMILE. Incidence of central islands was assessed through total corneal spherical aberration (SA) over 4 mm of central diameter and the SA was compared between two groups with and without safety loss (CDVA difference ≥0.1 logMAR from preoperative). The cut-off value for detecting the risk of postoperative central island development was calculated. The influence in accuracy was calculated through magnitude of error of the spherical equivalent and astigmatism, both for spectacle refraction at corneal plane (SE-Rx and AST-Rx) and for total corneal refractive power at 3 mm (SE-TCRP3 and AST-TCRP3). RESULTS: Five from 82 eyes resulted in a loss of safety, obtaining significant differences in SA, both preoperatively (p = .01) and postoperatively (p = .007) after stratification by safety loss. A preoperatively cut-off value ≤0.012 µm of SA predicted the appearance of central islands with sensitivity of 100% and specificity of 75%. Despite postoperative SA being related to the preoperative spherical equivalent, for both SE-Rx and SE-TCRP3, this tendency disappeared after readjusting results according to a nomogram. CONCLUSIONS: Central islands in SMILE, despite being a rare adverse event, can affect the safety of the procedure and are related to preoperative central steepness, not corrected by the spherical lenticule, which is clearly visible postoperatively.

Agreement and repeatability of objective systems for assessment of the tear film.

PURPOSE: To assess the agreement and repeatability of two objective systems for measuring the tear film stability. METHODS: Retrospective analysis of the tear film stability of 99 healthy right eyes measured with a videokeratoscope (VK) and the Optical Quality Analysis System (OQAS, Visiometrics). Two consecutive measures were taken with both systems, with an interval of 10 min between them. Variables included in the study were first and mean non-invasive break-up times (NIBUT and MNIBUT) measured with VK, and mean and standard deviation of the optical scattering index (OSIm and OSIsd) measured with OQAS. The agreement and repeatability of grading scales provided by both devices were also evaluated using the Cohen's k with quadratic weights. The Ocular Surface Disease index (OSDI) questionnaire was also passed out to all subjects. Correlations and associations between subjective and objective metrics were analyzed. RESULTS: Significant differences were found between consecutive measurements of NIBUT (p = 0.04) and MNIBUT (p = 0.01), but not for OSIm (p = 0.11) and OSIsd (p = 0.50). Grading scales resulted in fair (k = 0.20) or poor agreement (k = 0.04) between systems depending if the first or second trial was considered. The repeatability of the grading scale was good for OQAS (k = 0.59) and fair for VK (k = 0.37). No significant correlations or associations were found between OSDI and any of the metrics obtained with both devices (p ≥ 0.36). CONCLUSIONS: The two devices evaluated cannot be used interchangeably for the assessment of tear film stability. Good intrasession repeatability was obtained for tear film grading of the OQAS whereas it was fair for VK.

Relationship between lamina cribrosa displacement and trans-laminar pressure difference in papilledema.

PURPOSE: The purpose of this study was to describe morphological changes in lamina cribrosa (LC), prelaminar tissue thickness (PTT) and Bruch's membrane opening (BMO) in eyes affected by papilledema and correlate them with trans-LC-pressure difference (TLCD). METHODS: This was a prospective study, including twelve eyes newly diagnosed of papilledema. Eyes underwent scanning with Spectralis-OCT with enhanced depth imaging to compare BMO, anterior LC surface position (LC depth-LCD-) and PTT before and after oedema resolution. Correlation analysis between these parameters and TLCD was performed. RESULTS: TLCD inversely correlated with LCD at baseline and directly with LC reversal movement after lowering cerebrospinal fluid pressure (CSFP) (ρSpearman: -0.739, p = 0.006; ρSpearman: 0.844, p = 0.001 respectively). At onset, RNFL thickening and BMO were significantly larger in eyes with TLCD > -9.2 mmHg (group 2) compared with TLCD < -9.2 mmHg (group 1) [p = 0.007, p = 0.041 respectively]. A significant RNFL and BMO shrinking were observed, but they were significantly larger in group 2. The magnitude of LC displacement following oedema resolution was significantly larger and in the opposite direction in group 2 vs group 1 (-68.7 µm vs 19.5 µm, p = 0.016). TLCD correlated with RNFL thickening at baseline (ρSpearman: 0.667, p = 0.018) and with RNFL thinning at last visit (ρSpearman: 0.673, p = 0.017). TLCD correlated with mean deviation (MD) (ρSpearman: 0.712, p = 0.014) and visual field index (VFI) (ρSpearman: -0.657, p = 0.028) at onset. MD and VFI were worse in group 2. CONCLUSIONS: LC position was significantly related to TLCD in papilledema. Eyes with higher TCLD showed significantly larger backward LC movement, BMO shrinking and RNFL thinning after lowering CSFP compared with eyes with lower TLCD, where LC movement occurred in the opposite direction.

Bruch's membrane opening changes and lamina cribrosa displacement in non-arteritic anterior ischaemic optic neuropathy.

PURPOSE: To describe the morphological changes in the lamina cribrosa (LC) and prelaminar tissue (PT) from eyes with non-arteritic anterior ischaemic optic neuropathy (NAION) using enhanced depth imaging (EDI) optical coherence tomography (OCT), and to evaluate whether these changes correlate with retinal nerve fibre layer (RNFL) thickness and visual acuity (VA). DESIGN/METHODS: A prospective case-control study was performed, including 17 study eyes with NAION and 17 control, uninvolved eyes from 17 patients. Eyes underwent scanning with Spectralis-OCT at onset, 2 and 6 months after NAION. Bruch's membrane opening (BMO), anterior LC surface depth (LCD), LC thickness and PT thickness (PTT) were compared between study and control eyes. Correlation analysis was performed to evaluate the association between these parameters, RNFL thickness and VA. RESULTS: At presentation, average PT was 58.6% thicker in NAION eyes compared with healthy control eyes (p=0.001), followed by a significant thinning at 2 and 6 months (p=0.001). A significant LC forward displacement was observed at 2 and 6 months (p=0.001). BMO progressively shrunk at 2 and at 6 months (p<0.05). A significant correlation was found between PTT and RNFL thickness (ρSpearman=0.544, p=0.024) at onset, as well as between PTT and RNFL changes at 6 months (ρSpearman=0.545, p=0.036). BMO and RNFL changes were also correlated at 6 months (ρSpearman=0.750, p=0.001). CONCLUSIONS: At onset, a significant PT thickening, backward LC movement and BMO enlargement occurred in NAION eyes compared with unaffected eyes, and these changes significantly reversed during follow-up. PTT and RNFL changes were significantly correlated.