Influence of lens opacities and cataract severity on quantitative fundus autofluorescence as a secondary outcome of a randomized clinical trial

The aim of this study is to investigate the impact of age-related lens opacities and advanced cataract, quantified by LOCS III grading, on quantitative autofluorescence (qAF) measurements in patients before and after cataract surgery. Images from a randomized controlled trial evaluating the impact of femtosecond-laser assisted cataract surgery (FLACS) on retinal thickness were analyzed post-hoc. One-hundred and twenty eyes from 60 consecutive patients with age-related cataract were included and assessed with qAF and optical coherence tomography (OCT) before, 1, 3 and 6 weeks after cataract surgery (randomized 1:1 to FLACS or phacoemulsification). LOCS III grading was performed before surgery. Pre- to post-surgical qAF values, as well as the impact of LOCS III gradings, surgery technique, gender, axial length and age on post-surgery qAF values was investigated using generalized linear mixed models. For this analysis, 106 eyes from 53 patients were usable. No difference in qAF was found between FLACS and phacoemulsification (p > 0.05) and results were pooled for the total cohort. Mean pre-surgical qAF was 89.45 ± 44.9 qAF units, with a significant mean increase of 178.4–191.6% after surgery (p < 0.001). No significant difference was found between the three follow-up visits after surgery (p > 0.05). Higher LOCS III cortical opacity quantifications were associated with a significantly greater increase in qAF after surgery (estimate: 98.56, p = 0.006) and nuclear opacities showed a trend toward an increased change (estimate: 48.8, p = 0.095). Considerable interactions were identified between baseline qAF and cortical opacities, nuclear opacities and posterior subcapsular opacities, as well as nuclear opacities and cortical opacities (p = 0.012, p = 0.064 and p = 0.069, respectively). Quantitative autofluorescence signals are significantly reconstituted after cataract surgery and LOCS III gradings are well associated with post-surgical qAF values. Careful consideration of age-related lens opacities is vital for the correct interpretation of qAF, especially in retinal diseases affecting the elderly.ClinicalTrials.gov Identifier: NCT03465124.

Simulating Outcomes of Cataract Surgery: Important Advances in Ophthalmology

As the human eye ages, the crystalline lens stiffens (presbyopia) and opacifies (cataract), requiring its replacement with an artificial lens [intraocular lens (IOL)]. Cataract surgery is the most frequently performed surgical procedure in the world. The increase in IOL designs has not been paralleled in practice by a sophistication in IOL selection methods, which rely on limited anatomical measurements of the eye and the surgeon's interpretation of the patient's needs and expectations. We propose that the future of IOL selection will be guided by 3D quantitative imaging of the crystalline lens to map lens opacities, anticipate IOL position, and develop fully customized eye models for ray-tracing-based IOL selection. Conversely, visual simulators (in which IOL designs are programmed in active elements) allow patients to experience prospective vision before surgery and to make more informed decisions about which IOL to choose. Quantitative imaging and optical and visual simulations of postsurgery outcomes will allow optimal treatments to be selected for a patient undergoing modern cataract surgery. Expected final online publication date for the Annual Review of Biomedical Engineering, Volume 23 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Effectiveness of the Cataract Prevention in Patients with Epiretinal Membrane after Vitrectomy

Purpose: tо evaluate effectiveness of cataractogenesis prophylaxis in patients with epiretinal membrane (ERM) after vitrectomy based on the pirenoxin use.Patients and мethods. The study included 72 patients (64.5 ± 6.4 years old; 31 men, 41 women) with ERM before and after 25G microinvasive vitrectomy with removal of ERM. The 1-st group patients (36 eyes) received pirenoxin instillation (Catalin®; 3 times a day, 6 months) in addition to the standard pharmacological support. The 2-nd group patients received only standard therapy. All patients underwent: standard ophthalmologic examination; lens state photoregistration with an assessment of lens opacities intensity (LOCS-III classification) with the calculation of the cataract development index (CDI). These were control points: examination before vitrectomy and 5 months after surgery. At control points, the incidence of lens opacities in the observation groups was also evaluated. Statistical analysis included: calculation of the mean and its standard deviation (M ± s); assessment of the significance of differences in control points with each group (Wilcoxon's T-test) and between groups (Mann—Whitney U-test); Pearson xi-square test.Results: In the 1-st group (pirenoxin instillation), 6 months after vitrectomy and ERM removal, the following indicators were noted: the initial cataract incidence was 5.6 %; CDI — 0.36 ± 0.03 points, increasing the maximum corrected visual acuity (MCVA) from 0.31 ± 0.03 to 0.6 ± 0.05. In the 2-nd group similar indicators significantly differed from the 1-st group data: the initial cataract incidence was 36.1 % (Pearson xi-square test > 3; p < 0.05); CDI — 3.1 ± 0.3 points (p < 0.01); the MCVA increase from 0.3 ± 0.05 to 0.43 ± 0.1 (p < 0.05).Conclusion. Pirenoxin (Catalin®) has demonstrated quite high efficacy in the cataract prevention in patients after vitrectomy with ERM removal.

Study of ophthalmic pathology in persons affected by radiation incidents

Aim. To investigate changes in the lens layers in individuals who have been chronically exposed to radiation over a long time. Methods. An analysis of the results of examination by an ophthalmologist in the clinical Department of the URCRM in 2018–2019 1 298 people. The examination was carried out according to a special in-depth program with photo fixation of changes in the lens. Results. An in-depth ophthalmological examination of patients affected by radiation accidents in the Ural region revealed an increase in cataract cases with increasing age, which corresponds to the trends in non-irradiated population. Initial changes in the lens were first detected in the age group from 40 to 50 years. At the age of less than 40 years, 41 people examined had no lens pathology. Changes in the cortical layers of the lens are the most common initial pathology in the development of cataract – in the age categories from 40 to 49 years and from 50 to 59, they accounted for 75 % of all types of lens opacities. Changes in the anterior lens capsule accounted for 21 % of all types of opacities, in the cortex –52 %, in the nucleus – 15 %, in the posterior capsule – 12 %. According to the intensity of lens opacities, the most frequent opacities of stages 1 and 2 were found in all layers. Changes in the lens nucleus gradually increase with age to 28–37 % in the age groups older than 70 years. The same trend is established in the increase in the intensity of yellow color in the staining of the lens. Opacity in the posterior lens nucleces capsule was found in 1 person aged 40–49 years, the greatest changes in the posterior lens capsule were observed in the oldest age group (over 80 years) – 20 % of all opacities at this age. Key words: ionizing radiation; small doses; cataract; involution processes.

Lens opacity prevalence among the residents in high natural background radiation area in Yangjiang, China

The aim of the study was to evaluate the risk and threshold doses of lens opacity among residents exposed to low-dose radiation. Residents aged ≥45 years were recruited from a high natural background radiation (HNBR) area in Yangjiang City and a control area selected from nearby Enping City. Lens opacities (LOPs) were classified according to the Lens Opacities Classification System (LOCS) III system. Face-to-face interviews were conducted to collect information on lifestyles, migration and medical history. Life-time cumulative doses were estimated using gender, age, occupancy factors and environmental radiation doses received indoors and outdoors. Logistic regression analyses were conducted to estimate the dose response and determine thresholds. In the HNBR area, among 479 study participants, 101 (21.1%), 245(51.1%) and 23 cases (4.8%), respectively, of cortical, nuclear and posterior subcapsular (PSC) LOPs were found. In the control area, those types of LOPs were identified among 58 cases (12.6%), 206 cases (51.2%) and 6 cases (1.3%) of 462 examinees, respectively. Cumulative eye lens dose was estimated to be 189.5 ± 36.5 mGy in the HNBR area. Logistic analyses gave odds ratios at 100 mGy of 1.26 [95% confidence interval (CI) 1.00–1.60], 0.81 (95% CI 0.64–1.01) and 1.73 (95% CI 1.05–2.85) for cortical, nuclear and PSC LOPs, respectively. For cortical LOPs, a logistic analysis with a threshold dose gave a threshold estimate of 140 mGy (90% CI 110–160 mGy). The results indicated that population exposed to life-time, low-dose-rate environmental radiation was at an elevated risk of cortical and PSC LOPs. A statistically significant threshold dose was obtained for cortical LOPs and no threshold dose for PSC LOPs.

CORTICAL SPOKES CATARACT

A 40 years old man presented with bilateral mild dimness of vision and mild glare. Diffuse and focal illumination on slit lamp biomicroscopy did not reveal any pathology. Retro-illumination on slit lamp showed faint bilateral spokes like cortical lens opacities. Retro-illumination mode on Auto-Ref/Keratometer (HRK 7000A, Huvitz, Anyang-si, Gyeonggi-do, Republic of Korea) prominently revealed these insignificant bilateral spokes like cortical opacities (cataracts). Visual acuity was 6/9 in both eyes. No intervention was advisable and the patient was reassured.