Advances in ophthalmology practice and research最新文献

Background

The lens zonule, a circumferential system of fibres connecting the ciliary body to the lens, is responsible for centration of the lens. The structural, functional, and positional abnormalities of the zonular apparatus can lead to the abnormality of the intraocular structure, presenting a significant challenge to cataract surgery.

Main text

The lens zonule is the elaborate system of extracellular fibers, which not only centers the lens in the eye but also plays an important role in accommodation and lens immunity, maintains the shape of the lens, and corrects spherical aberration. The zonules may directly participate in the formation of cataract via the immune mechanism. Abnormal zonular fibers that affect the position and shape of the lens may play an important role in the pathogenesis of angle closure disease and increase the complexity of the surgery. Capsular tension rings and related endocapsular devices are used to provide sufficient capsular bag stabilization and ensure the safety of cataract surgery procedures. Better preoperative and intraoperative evaluation methods for zonules are needed for clinicians.

Conclusions

The microstructure, biomechanical properties, and physiological functions of the lens zonules help us to better understand the pathogenesis of cataract and glaucoma, facilitating the development of safer surgical procedures for cataract. Further studies are needed to carefully analyze the structure–function relationship of the zonular apparatus to explore new treatment strategies for cataract and glaucoma.

Background

The fast development of swept-source optical coherence tomography (SS-OCT) and swept-source optical coherence tomography angiography (SS-OCTA) enables both anterior and posterior imaging of the eye. These techniques have evolved from a research tool to an essential clinical imaging modality.

Main text

The longer wavelength and faster speed of SS-OCT and SS-OCTA facilitate better visualization of structure and vasculature below pigmented tissue with a larger field of view of the posterior segment and 360-degree visualization of the anterior segment. In the past 10 years, algorithms dealing with OCT and OCTA data also vastly improved the image quality and enabled the automated quantification of OCT- and OCTA-derived metrics. This technology has enriched our current understanding of healthy and diseased eyes. Even though the high cost of the systems currently limited the widespread use of SS-OCT and SS-OCTA at the first beginning, the gap between research and clinic practice got obviously shortened in the past few years.

Conclusions

SS-OCT and SS-OCTA will continue to evolve rapidly, contributing to a paradigm shift toward more widespread adoption of new imaging technology in clinical practice.

Background

In the general population, 1 in 2000 people has keratoconus. Indians and other people from Southeast Asia have a higher incidence of keratoconus. Children with keratoconus typically present earlier in life and with a more severe disease. Rubbing the eyes has been identified as a risk factor. Children have a higher incidence and a faster rate of keratoconus progression. Visual rehabilitation in children with keratoconus is challenging. They have a low compliance with contact lens use. Many of these children require penetrating keratoplasty at an early age. Therefore, stopping the progression of keratoconus in children is of paramount importance.

Main text

Compared to treatment, keratoconus progression prophylaxis is not only preferable, but also easier. Corneal collagen cross-linking has been shown to be safe and effective in stopping its progression in children. The Dresden protocol, which involves central corneal deepithelization (7–9 ​mm), saturation of the stroma with riboflavin (0.25%), and 30 ​min UV-A exposure, has proven to be the most successful. Two significant disadvantages of the typical Dresden regimen are the prolonged operating time and the significant post-operative pain. Accelerated-CXL (9 ​mW/cm² x 10 ​min) has been studied to reduce operative time and has been shown to be equally effective in some studies. Compared to accelerated CXL or traditional CXL, epi-off procedures, transepithelial treatment without the need for de-epithelialization and without postoperative discomfort, have been shown to be safer but less effective. Corneal crosslinking should only be performed after treating children with active vernal keratoconjunctivitis. Corneal opacity, chronic corneal edema, sterile infiltrates, and microbial keratitis have been reported after cross-linking of corneal collagen.

Conclusions

The "Dresden protocol", also known as the conventional corneal cross-linking approach, should be used to halt the progression of keratoconus in young patients. However, if the procedure needs to be completed more rapidly, accelerated corneal crosslinking may be considered. Transepithelial corneal cross-linking has been proven to be less effective at stabilizing keratoconus, although being more safer.

Background

Enhanced depth-of- focus intraocular lenses (EDOF IOL) have filled the gap between monofocal and multifocal intraocular implants with optical qualities of monofocal lenses and usually minor dysphotopsias typical for multifocal lenses. The purpose of this study was to evaluate visual outcomes after bilateral implantation of a new EDOF IOL in patients with requirements for perfect near and intermediate vision.

Methods

The study included 15 patients (29 eyes as one was amblyopic) with bilateral implantation of LUXSMART EDOF IOL (Bausch & Lomb) with a targeted myopia (between –0.25 and –0.50D) in both eyes. Monocular corrected and uncorrected visual acuity for far, intermediate and near as well as refractive outcomes were evaluated at 1, 3, 6 and 12 months after the surgery. Additionally, binocular visual acuity, contrast sensitivity and defocus curve were measured at the final follow-up visit. At 12 months’ visit patients completed a questionnaire evaluating patient satisfaction, spectacle independence and presence of dysphotopsias.

Results

Binocular uncorrected visual acuities at 12 month’s visit were 0.13 ​± ​0.16, 0.06 ​± ​0.08, 0.07 ​± ​0.09 and 0.15 ​± ​0.09 logMAR for far distance, 80 ​cm, 66 ​cm and 40 ​cm respectively. Corrected binocular visual acuities at 12 months were 0.00 ​± ​0.00, 0.05 ​± ​0.07, 0.05 ​± ​0.06, 0.13 ​± ​0.16 respectively for distance, 80 ​cm, 66 ​cm and 40 ​cm. Automated refraction spherical equivalent at 12 months’ visit stood at –0.70 ​± ​0.48D, which was 0.46D less than calculated biometric target, however spherical equivalent of subjective refraction at 12 months equaled –0.49 ​± ​0.46D, which was closer to preoperative biometric target. Defocus curve had gentle shape without peaks typical for monofocal IOLs. Binocular contrast sensitivity results were superior to average results for that age group and equaled 1.78 ​± ​0.16 logMAR without correction and 1.81 ​± ​0.13 logMAR with correction. Spectacle independence for near and intermediate distances was achieved in all patients and for far distance in 73.3% of patients. Burdensome dysphotopsias were not reported in any case.

Conclusions

EDOF IOLs targeted bilaterally at low myopia can provide excellent near and intermediate visual acuity and independence of any optical correction in majority of cases. This approach can be used in selected patients who are focused on stationary activities.

Purpose

To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens (IOL) calculation.

Methods

The keratometric astigmatism measured by Lenstar LS 900 (KCA_L), keratometric astigmatism (KCA_P) and total corneal astigmatism (TCA) measured by Scheimpflug camera (Pentacam HR) were documented and analyzed accordingly. Three deduction models using different parameters were compared. Model 1: KCA_L ​+ ​keratometric corneal surgically induced astigmatism (KCSIA, 0.30 D @ 50°); Model 2: KCA_P ​+ ​KCSIA); Model 3: TCA ​+ ​total CSIA (TCSIA, 0.23 D @ 50°). The prediction errors of each model as the difference vector between the actual and the intended residual astigmatism were compared.

Results

Seventy-six eyes implanted with toric multifocal IOLs were included in this study. The vector differences of the actual KCSIA and TCSIA were statistically significant in the total sample and against-the-rule (ATR) subgroup (both P ​< ​0.05). Model 1 deduced the smallest mean values of prediction error, while that of Model 3 were smaller than that of Model 2, both in the total sample and the ATR subgroups (all P ​< ​0.05). Meanwhile, in the total sample and ATR subgroups, the centroid vector magnitudes of Model 3 were smaller than that of Model 1 (0.31 ​± ​0.76 D and 0.39 ​± ​0.76 D).

Conclusions

The calculation of toric multifocal IOL should be individualized especially in the ATR eyes for the impact of PCA on the estimation of the preoperative corneal astigmatism and the CSIA.

Background

Due to media opacity, it is usually difficult to accurately evaluate the postoperative visual acuity in cataracts patients. As a small and portable tool, the critical flicker fusion frequency (CFF) device reflects the temporal resolution of visual function and has been widely used in clinical research. However, poor understanding of the technique and equipment limitations have restricted its clinical application in China.

Main text

There was a decrease in the CFF value in various ophthalmic diseases, indicating that the CFF is sensitive to detect visual functional changes. A number of studies have shown that the CFF test can accurately distinguish patients with simple cataracts from those with cataracts combined with fundus disease, and, as a visual test, it can more accurately predict postoperative visual acuity without being affected by media opacity. This study comprehensive reviews the basic principles of CFF and its application in ophthalmology, especially in cataracts.

Conclusions

As one of the tools for dynamic visual function detection, the CFF test could help doctors to assess the possible presence of fundus disease in cataracts patients, especially in eyes with dense cataracts, and more precisely provide a reasonable visual prognosis than other available visual tests.

Background

The novel severe acute respiratory syndrome coronavins 2 (SARS-CoV-2) led to the severe Corona Virus Disease 2019 (COVID-19) outbreak that started in December 2019 in China and caused enormous health and economic problems worldwide. Over time, SARS-CoV-2 has demonstrated the capacity for mutation. As the most prevalent new coronavirus variety worldwide, the Omicron variant has supplanted the Delta variant. The COVID-19 primarily damages the immune system and the lungs, but it can also harm other organs secondarily, depending on the patients' co-existing conditions.

Main Text

COVID-19 is associated with ophthalmic manifestations such as conjunctival congestion, tear overflow, and conjunctival edema, with the majority of eye complications occurring in patients with severe infection. The virus may make a patient more susceptible to thrombotic conditions that affect venous and arterial circulation. Meanwhile, it can lead to efferent complications and mucormycosis which is more common in patients with diabetes or who have critical or severe SARS-CoV-2 infection. Significantly, there are a number of ocular side effects following the COVID-19 vaccination, such as herpetic keratitis and facial nerve palsy, which have been reported. These side effects may be caused by the vaccinations' propensity to trigger autoimmune symptoms or thromboembolic events. At present, large-scale nucleic acid testing mainly relies on nasopharyngeal swabs and throat swabs. Tear samples and conjunctival swabs may be helpful samples for the diagnosis of ocular SARS-CoV-2 infection. The eye could be a new route of infection, and finding ways such as effective environmental disinfection, scientific administrative control management, qualified personal protection and other measures to protect the eyes could further reduce the risk of infection.

Conclusions

This review aims to sum up the ocular complications of COVID-19, the possible pathogenesis, and preventive strategies to protect ophthalmology practitioners and patients by reviewing the currently available literature on the topic.

Purpose

To outline the characteristics of Combined Hamartoma of the Retina and Retinal Pigmentation Epithelium (CHRRPE) and provide a comprehensive overview of surgical management of epiretinal membrane (ERM) caused by CHRRPE.

Main text

CHRRPE is a rare ocular tumor. It clinically mimics other diseases such as retinoblastoma and choroidal melanoma. The present study reviewed the multimodal imaging of CHRRPE, highlighted the multimodal imaging modalities which are useful for revealing the unique features of CHRRPE and hence allowing physicians to confirm the diagnosis.

Although most of CHRRPEs are benign harmatoma, progressive visual loss may occur because of the traction of the tumor and other complications. It is treated through surgical removal of the ERM caused by CHRRPE to free retina from the traction. Currently, there is no consensus on the surgical management of CHRRPE. Therefore, the current review was designed to explore the surgical management of ERM caused by CHRRPE and hence provide updated data on this subject.

Conclusions

Multimodal imaging technologies, especially optical coherence tomography (OCT), significantly contributes to the diagnosis of CHRRPE and visual prognosis. Surgical management of CHRRPE through removal of ERM is beneficial in patients with worsening VA which is secondary to ERM which is associated with CHRRPE. However, the strategy is limited to patients with long-standing poor vision. However, earlier surgical therapy and subsequent postoperative amblyopia therapy can be explored for children of amblyogenic age.