Progression of posterior vitreous detachment after cataract surgery

Understanding cataract development in axial myopia: The contribution of oxidative stress and related pathways

Myopia is an evolving global health challenge, with estimates suggesting that by 2050 it will affect half of the world's population, becoming the leading cause of irreversible vision loss. Moreover, myopia can lead to various complications, including the earlier onset of cataracts. Given the progressive aging of the population and the increase in life expectancy, this will contribute to a rising demand for cataract surgery, posing an additional challenge for healthcare systems. The pathogenesis of nuclear and posterior subcapsular cataract (PSC) development in axial myopia is complex and primarily involves intensified liquefaction of the vitreous body, excessive production of reactive oxygen species, impaired antioxidant defense, and chronic inflammation in the eyeball. These factors contribute to disruptions in mitochondrial homeostasis, abnormal cell signaling, lipid peroxidation, protein and nucleic acid damage, as well as the induction of adverse epigenetic modifications. Age-related and oxidative processes can cause destabilization of crystallins with subsequent protein accumulation, which finally drives to a lens opacification. Moreover, an altered redox status is one of the major contributors to the pathogenesis of PSC. This review aims to summarize the mechanisms known to be responsible for the accelerated development of cataracts in axial myopia and to enhance understanding of these relationships.

Vision degrading myodesopsia from vitreous floaters in the young: An important aspect of myopia

Vitreous floaters are visual phenomena resulting from floating opacities inside the eye that disturb vision. The opacities consist of microscopic collagen fibers that aggregate in myopia and during aging. These collagen fibers are then seen as irregular, sometimes worm-like shadows or structures of a translucent to black color. Because of the floating aspect, they tend to follow the movements of the eye, causing distress and having a negative impact on a patient's quality of life due to degradation in contrast sensitivity function. This is referred to as vision degrading myodesopsia (VDM). The overall importance of floaters and their effect on quality of life gained attention in recent years. While the existence of floaters alone is labeled as harmless, there is an increasing group of young people suffering from VDM. This coincides with the growing prevalence of myopia. Indeed, myopia and myopic vitreopathy are the major causes of VDM in the young. This aspect of myopia, however, is often overlooked. We review the current research status in floater formation, quality of life impact, symptom assessment, localization and therapeutic options for vitreous floaters from the perspective of a myopic, potentially younger patient group.

Examination of Vitreolenticular Interface in Relation to Different Phacoemulsification Parameters in Early and Late Postoperative Period

Background: The surgical parameters of phacoemulsification can significantly impact the behavior of the anterior hyaloid membrane (AHM). Methods: In this prospective study, anterior segment optical coherence tomography was used to examine the attachment or detachment of the AHM of 82 eyes after uneventful phacoemulsification preoperatively and postoperatively over 1 year. The impacts of the capsulorhexis' size, number of hydrodissections, nuclear sclerosis grade, cumulative dissipated energy (CDE), ultrasonic time, total surgical time, weakness of zonular fibers, presence of lens materials in Berger's space (LM-BS), and fluid usage were investigated in relation to the behavior of the AHM. Results: A significant linear trend regarding anterior vitreous detachment (AVD) was observed in the presence of zonular weakness and high CDE at all postoperative times (p ≤ 0.024 and p ≤ 0.005, respectively). Similarly, AVD was observed at 1-month, 3-month, and 1-year follow-ups in cases of high nuclear sclerosis grades (p ≤ 0.044) and high fluid usage (p ≤ 0.021). A significant correlation was observed in the group of LM-BS as the zonular weakness value increased (OR: 0.085; 95% CI: 0.017 to 0.420; p = 0.002), and the fluid usage was also significantly higher (OR: 1.049; 95% CI: 1.003-1.096; p = 0.037). Conclusions: Zonular weakness, high CDE, a hard nucleus, and high fluid usage are risk factors for postoperative AVD.

Posterior vitreous detachment rates post-uncomplicated phacoemulsification surgery: a systematic review

PURPOSE

It is commonly accepted that phacoemulsification surgery is a risk factor for the development of posterior vitreous detachment (PVD) and may accelerate the process. This is an important consideration particularly in cases involving young patients who pre-operatively have no PVD, given the increased risk of retinal tears and detachments.

METHODS

A comprehensive literature search was conducted to identify studies reporting incidence of PVD post-uncomplicated phacoemulsification surgery. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement was used for search strategy. Of 3071 titles, 7 studies met the inclusion criteria; The outcomes measured were PVD occurrence by (1) time, (2) type, (3) age, (4) gender and (5) axial length, with all statistical analysis performed using Review Manager.

RESULTS

A total of 2034 eyes were included for analysis with a mean follow-up time of 28.3 months. 33.3% of patients developed a PVD, either partial or complete, with rates increasing in a time dependent manner. No significant difference was noted in sub-group analysis by age, gender or axial length.

CONCLUSIONS

The results from our systematic review show that uncomplicated phacoemulsification accelerates the physiological process of PVD development. Pre-operative evaluation of the vitreoretinal interface should be performed with careful post-operative follow-up advised in those without a pre-existing PVD.

Long-term efficacy and safety of YAG laser vitreolysis for vision degrading myodesopsia

AIM

To assess the long-term efficacy and safety of yttrium-aluminum garnet (YAG) laser vitreolysis for vision degrading myodesopsia (VDM) caused by posterior vitreous detachment (PVD).

METHODS

This retrospective study reviewed VDM patients of PVD type undergoing YAG laser vitreolysis. The baseline demographic information, the patterns of floaters, the number of floaters, and the subjective improvement of floater sympotoms (ranging from 0 to 100%) from medical records were collected. Significant improvement was defined as a relief of floater symptoms of ≥50% at the final visit. The long-term efficacy and safety of YAG laser vitreolysis were analyzed. The risk factors linked to significant improvement of floater symptoms were defined using univariate and multivariate logistic regression analyses.

RESULTS

The final analysis included 221 patients with VDM. The mean age of patients was 61.08±7.74y, and the mean length of follow-up was 21.38±5.61mo. Totally 57.01% of patients experienced a significant improvement in their floater symptoms after YAG laser therapy, and none of them developed delayed retinal abnormalities such as retinal tears or detachments. Age (OR=1.049, 95%CI=1.007-1.092, P=0.021) was identified as a significant risk factor for significant improvement in VDM.

CONCLUSION

YAG laser vitreolysis is an effective and secure treatment for PVD-type VDM, and patients of advanced age are more likely to get favorable outcomes.

Effect of Phacoemulsification on Sub Foveal Choroidal and Central Macular Thickness as measured by Swept Source Optical Coherence Tomography

Objectives

To study the effect of Phacoemulsification on Sub Foveal Choroidal Thickness (SFCT) and Central Macular Thickness (CMT) as measured by Swept Source Optical Coherence Tomography (OCT).

Methods

This experimental study was conducted at Armed Forces Institute of Ophthalmology (AFIO), Rawalpindi from April 2021 to February 2022. One hundred eyes of 100 patients with age related cataract underwent uneventful phacoemulsification surgery. Pre-operative SFCT and CMT was measured and compared with SFCT and CMT at one week, one month and three months after surgery using swept source OCT.

Results

Mean age of study population was 56.76±8.31 years. Out of 100 patients, 46 (46%) were males and 54 (54%) were females. Mean pre-operative CMT, one week, one month and three months post-operative CMT was 233.95±9.46 μm, 232.88±8.59 μm, 230.38±10.62 μm and 230.67±7.55 μm respectively. Mean pre-operative SFCT, one week, one month and three months post-operative SFCT was 337.14±8.41 μm, 339.14±9.63 μm, 339.39±11.96 μm and 351.39±9.19 μm respectively. The difference of mean change in CMT from baseline at one week, one month and three months post-operatively was not statistically significant. The difference of mean change in SFCT from baseline at one week and one month post-operatively was not statistically significant. However, the difference of mean change in SFCT from baseline at three months post-operatively was statistically significant (p<0.05).

Conclusion

Uneventful phacoemulsification surgery does not have any effect on central macular thickness, however there is a significant increase in subfoveal choroidal thickness at three months after surgery.

Impact of phacoemulsification on posterior vitreous detachment formation in eyes with vitreomacular traction

Purpose

To investigate the impact of phacoemulsification on posterior vitreous detachment formation in eyes with vitreomacular traction (VMT) with or without macular holes.

Methods

A retrospective search of the medical records was conducted to identify patients with VMT who underwent cataract surgery at Mass Eye and Ear from 2016 to 2021. Patient demographics, ocular comorbidities, and clinical characteristics were extracted from the record, and optical coherence tomography images were assessed to confirm VMT and the presence of a lamellar or full-thickness macular hole (FMTH). Patients who underwent vitrectomy prior to cataract surgery were excluded.

Results

A total of 22 patients (15 women [68%]) met inclusion criteria (average age, 71 years). Fifteen eyes had an associated epiretinal membrane (63%), 7 had a lamellar hole (29%), and 8 had an FTMH (33%). Epiretinal membrane was present in 3 of 7 eyes with lamellar holes (43%) and 4 of 8 with a FTMH (50%). No eyes developed a complete posterior vitreous detachment following phacoemulsification. In 2 cases, there was progression of the macular hole stage following phacoemulsification. Ten eyes underwent subsequent pars plana vitrectomy (PPV). There was no statistically significant difference in visual acuity between eyes pre- and post-phacoemulsification; however, there was a statistically significant improvement in visual acuity pre- and post-PPV.

Conclusions

Unlike other studies, in this case series of 24 eyes with VMT or VMT with holes, no cases of full posterior vitreous detachment occurred following unremarkable phacoemulsification or YAG capsulotomy.

Comparison of Long-Term Corneal Astigmatic Changes After Cataract Surgery in Eyes with Superior or Horizontal Clear Corneal Incisions

PURPOSE

To compare long-term corneal astigmatic changes after stabilization of surgically induced astigmatism (SIA) subsequent to phacoemulsification between eyes that underwent superior clear corneal incision (CCI) or horizontal CCI.

DESIGN

Retrospective, comparative case series.

METHODS

We examined the anterior corneal astigmatism of eyes that underwent a 2.4 mm-superior CCI (superior CCI group, n=43) or horizontal CCI (horizontal CCI group, n=43) preoperatively, on the postoperative day that SIA stabilized (baseline), and at ≥7 years post-baseline using an autokeratometer. Corneal astigmatic changes from baseline to ≥7 years post-baseline (mean duration 8.74 years in the superior CCI group and 9.05 years in the horizontal CCI group) were decomposed to vertical/horizontal (Rx) and oblique astigmatic change components (Ry), and compared between the 2 groups.

RESULTS

The mean corneal astigmatism components changed significantly toward against-the-rule (ATR) astigmatism in the superior CCI group and with-the-rule astigmatism in the horizontal CCI group within 6 months postoperatively. After stabilization of the SIA, both groups showed a significant increase in the mean Rx and no significant change in the mean Ry over approximately 9 years, indicating a long-term ATR shift. The mean changes in the Rx and Ry did not differ significantly between the superior and horizontal CCI groups. Double angle-plots revealed a similar degree of ATR shift between the 2 groups over the 9 years.

CONCLUSION

After stabilization of the SIA, a similar degree of ATR change occurred subsequent to superior and horizontal CCIs over approximately 9 years, suggesting that CCI direction does not affect long-term astigmatic changes.

Posterior vitreous detachment after cataract surgery in eyes with high myopia: an optical coherence tomography study

PURPOSE

To compare the progression of posterior vitreous detachment (PVD) after cataract surgery in eyes with high myopia with that in eyes without high myopia.

STUDY DESIGN

Prospective observational study.

METHODS

Eighty eyes of 80 patients with high myopia and 160 eyes of 160 patients without high myopia scheduled for phacoemulsification were recruited. PVD status was examined using swept-source optical coherence tomography at 2 days postoperatively (baseline) and at 3, 6, and 12 months postbaseline and classified into 5 stages: 0 (no PVD), 1 (paramacular PVD), 2 (perifoveal PVD), 3 (peripapillary PVD), and 4 (complete PVD). The PVD stage and incidence of progression to complete PVD of the 2 groups were compared.

RESULTS

The mean PVD stage did not differ significantly between the groups at baseline or at 3 months postbaseline but was significantly more progressed in the high myopia group than in the nonhigh myopia group at 6 months and 12 months postbaseline (P ≤ 0.0201). The Kaplan-Meier survival rate for complete PVD was significantly lower in the high myopia group (P = 0.0129). After adjusting for age, sex, and baseline PVD stage, the hazard ratio for complete PVD was 1.68-fold higher in the high myopia group than in the nonhigh myopia group (P = 0.0326, 95% CI 1.04-2.70).

CONCLUSION

After cataract surgery, PVD progressed significantly faster in eyes with high myopia than in eyes without high myopia, and the relative risk for complete PVD was 1.68-fold higher in eyes with high myopia, suggesting that highly myopic eyes are at considerably high risk for retinal disease postoperatively.