Influence of cataract surgery on optical coherence tomography and neurophysiology measurements in patients with retinitis pigmentosa

Retinitis Pigmentosa: Current Clinical Management and Emerging Therapies

Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies characterized by the degeneration of rod photoreceptors, followed by the degeneration of cone photoreceptors. As a result of photoreceptor degeneration, affected individuals experience gradual loss of visual function, with primary symptoms of progressive nyctalopia, constricted visual fields and, ultimately, central vision loss. The onset, severity and clinical course of RP shows great variability and unpredictability, with most patients already experiencing some degree of visual disability in childhood. While RP is currently untreatable for the majority of patients, significant efforts have been made in the development of genetic therapies, which offer new hope for treatment for patients affected by inherited retinal dystrophies. In this exciting era of emerging gene therapies, it remains imperative to continue supporting patients with RP using all available options to manage their condition. Patients with RP experience a wide variety of physical, mental and social-emotional difficulties during their lifetime, of which some require timely intervention. This review aims to familiarize readers with clinical management options that are currently available for patients with RP.

Cataract surgery in patients with retinitis pigmentosa: systematic review

Retinitis pigmentosa (RP) is an inherited bilateral retinal degenerative disease with an incidence of 1 in 4000 people. RP affects more than 1 million individuals worldwide. Although night blindness and restricted visual field are the most typical symptoms of these individuals, generalized vision loss due to cataracts can be expected in the latter stages of the disease. It has been demonstrated that posterior subcapsular cataract is the most prevalent cataract in younger individuals with RP, as opposed to age-related cataracts. Although most ophthalmologists may have a negative view of cataract surgery in patients with RP, it appears that it can play an important role in the visual restoration of patients with RP. However, there are concerns about performing cataract surgery for patients with RP. Herein, a systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses on databases of MEDLINE and Scopus.

Effects and Prognosis of Cataract Surgery in Patients with Retinitis Pigmentosa

INTRODUCTION

Cataract extraction could improve visual acuity (VA) for patients with retinitis pigmentosa (RP), while the surgery may increase photoreceptor degeneration through light damage. In this study, we conducted a systematic review and meta-analysis to investigate the effectiveness and prediction of VA after cataract surgery in patients with RP.

METHODS

We comprehensively extracted data from literature of available studies with quality control processing. Improvement of VA before and after cataract surgery of different durations of follow-up and different structural integrity of the preoperative macular ellipsoid zone (EZ) in patients with RP were compared. VA was measured by the logarithm of the minimum angle of resolution (logMAR).

RESULTS

Sixteen studies were subjected to analysis. Postoperative VA was significantly improved versus preoperative, with a mean difference (MD) of 0.57 [95% confidence interval (CI) 0.45, 0.69], and a fixed-effect model was applied during follow-up durations of 1 day to 1 month (I² = 0%). Similarly, for follow-up durations of 1-3 months, 3-6 months, and 6-12 months, postoperative VAs were all better than preoperative values, with MDs of 0.36 (95% CI 0.31, 0.41), 0.35 (95% CI 0.23, 0.46), and 0.22 (95% CI 0.14, 0.30) (I² < 50%). For follow-up duration of 1-5 years, the random-effect model was applied for higher heterogeneity (I² = 81%), with an MD of 0.26 (95% CI 0.09, 0.43). There was no significant difference in the improvement of the EZ-invisible group, with an MD of 0.27 (95% CI - 0.17, 0.70) (I² = 82%). There were significant differences between EZ-abnormal and EZ-normal groups in preoperative and postoperative VA, with MDs of 0.56 (95% CI 0.27, 0.85) and 0.46 (95% CI 0.27, 0.65) (I² > 50%).

CONCLUSIONS

Cataract surgery could improve VA for patients with RP during long-term follow-up, and the surgery is not recommended for patients with invisible preoperative macular EZ. However, further studies are required to address the problem of excessive light exposure to the degenerated retina in patients with RP with the cataract removed. The study protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (CRD42022340165).

Effect of lens capsular tension ring on preventing capsular contraction syndrome in the surgery of retinitis pigmentosa combined with cataract: Retrospective case series

PURPOSE

To observe the effect of phacoemulsification and intraocular lens (IOL) implantation with or without lens capsular tension ring (CTR) on retinitis pigmentosa (RP) combined with cataract patients.

DESIGN

Retrospective cases series study.

METHODS

Sixty-three cases (84 eyes) of RP with cataract were collected, including 30 males and 33 females. Phacoemulsification with 3.0 mm clear corneal incision was performed in all the patients. IOL and CTR implantation were performed in 44 eyes, and IOL implantation alone was performed in 40 eyes. All cases were followed up at 1 day, 1 week and 1, 3, 6,12 months after the surgery to compare the best-corrected visual acuity (BCVA), intraocular pressure (IOP), corneal endothelial cell count (ECC) and complications before and after the surgery.

RESULTS

All surgery were successfully completed by the same physician, and IOL and CTR were all implanted in capsule without complications. The BCVA at 6 months after surgery was 0.91 ± 0.88 LogMAR, showing an improvement compared with the BCVA(1.3 ± 0.7LogMAR) before surgery and there was a statistically significant difference (P = .003). Four cases of capsule contraction syndrome (CCS) occurred in no CTR implantation group and there was no CCS in CTR group. There was a statistically significant difference in the incidence of CCS between two groups (P = .047).

CONCLUSIONS

Phacoemulsification for RP combined with cataract is safe and reliable, and CTR implantation is conducive to reducing the complications caused by capsule contraction.

Cataract surgery in retinitis pigmentosa

Purpose:

The aim of this study was to evaluate visual outcomes of cataract surgery in patients with retinitis pigmentosa.

Methods:

This retrospective case series includes a review of the medical records of all patients with retinitis pigmentosa undergoing cataract surgery between 2005 and 2018. The primary outcome measure was corrected distant visual acuity and change in vision impairment after surgery.

Results:

Of the 103 (132) patients, 60 (58.3%) were men and 43 (41.7%) were women. The mean age of the study population was 51.3 ± 11.3 (22–74) years. The mean symptom duration was 35.4 ± 44.5 (1–300) months. The most common morphology of cataracts was a combination of nuclear sclerosis, posterior subcapsular, and cortical cataract (n = 65 eyes, 49.3%). Phacoemulsification (87 eyes, 65.9%) was the preferred surgical technique. The mean preoperative corrected distant visual acuity of 1.21 ± 0.87 log MAR units improved significantly (P < 0.001) to 0.60 ± 0.56 log MAR units after surgery. The number of blind patients reduced from 27 (26.2%) to 8 (7.8%) patients. Zonular dialysis and posterior capsule tear were seen in six (4.5%) eyes each. Good preoperative vision (odds ratio: 6.1 [95% confidence interval: 2.9–13.0], P < 0.0001) was associated with better outcome, wheras reduced central macular thickness (odds ratio: 3.5 [95% confidence interval: 1.3–9.2], P = 0.011) was associated with poor outcome.

Conclusion:

A considerable number of patients presented with advanced cataracts and severe vision impairment. Significant improvement in visual acuity and alleviation of vision impairment was seen after surgery, with few complications. Good preoperative visual acuity predicted a good outcome, whereas macular thinning predicted a poor outcome.

A Review of Complicated Cataract in Retinitis Pigmentosa: Pathogenesis and Cataract Surgery

Retinitis pigmentosa (RP) is a set of inherited retinal degenerative diseases that affect photoreceptor and retinal pigment epithelial cells (RPEs), possibly associated with some ocular complications, including cataract. The complicated cataract formation is most likely the result of RP-related inflammation response, and the most common morphology category is posterior subcapsular cataract (PSC). Despite the absence of curative pharmacologic treatment, phacoemulsification with intraocular lens implantation to deal with opacification in the lens is preferred due to the considerable visual outcomes. However, the incidence of intraocular and postoperative complications is higher in RP patients than those without, including intraoperative phototoxic retinal damage, posterior capsular opacification (PCO), capsular contraction syndrome (CCS), pseudophakic cystoid macular edema (PCME), increased postoperative intraocular pressure (IOP), and intraocular lens (IOL) dislocation. Hence, it needs much attention to surgery progress and close follow-up. In this review, we discuss the current understanding of RP patients with complicated cataracts from morphology to potential pathogenesis to cataract surgical procedure and provide a concise description and the recommended management of related surgery complications to broaden the knowledge and lower the latent risks to yield better clinical outcomes.

Impact of Trifocal and Trifocal Toric Intraocular Lenses on Spectral-domain OCT Retinal Measurements

PRECIS

Monofocal, trifocal, and trifocal toric intraocular lenses (IOLs) induce similar changes on overall retinal optical coherence tomography (OCT) measurements.

PURPOSE

The purpose of this study was to assess whether trifocal and trifocal toric IOLs affect the measurement of retinal parameters using spectral-domain OCT.

METHODS

This cross-over study included patients undergoing implantation of a trifocal IOL: AcrySof IQ PanOptix, a trifocal toric IOL: AcrySof IQ PanOptix Toric, and a monofocal IOL: AcrySof IQ. The monofocal group was considered as the control group. The refractive target was emmetropia in all cases. Mean average macular thickness, macular volume, and retinal nerve fiber layer (RNFL) thickness were measured with the Cirrus HD-OCT. All measurements were performed before and 3 months after the surgery.

RESULTS

The study analyzed 150 eyes of 150 patients (50 for each IOL group). Macular thickness and macular volume showed statistically significant differences before and after the surgery for the 3 groups (P<0.05 in all cases). RNFL thickness was found to be similar before and after the surgery in all groups (P>0.05 in all cases). Mean difference values (before and after the surgery) in the monocular, trifocal, and trifocal toric group for macular thickness, macular volume, and RNFL thickness were 4.9±7.8, 7.9±10.0, and 7.7±13.7 µm, respectively; 0.1±0.2, 0.2±0.4, and 0.2±0.3 mm3, respectively; and 0.8±5.5, 1.3±6.0, and 0.8±6.7 µm, respectively. Mean differences were found to be similar for the 3 groups.

CONCLUSION

The trifocal and the trifocal toric IOLs under study did not induce an additional impact on spectral-domain OCT retinal measurements compared with monofocal IOLs.

Using Retinal Imaging to Study Dementia

The retina offers a unique "window" to study pathophysiological processes of dementia in the brain, as it is an extension of the central nervous system (CNS) and shares prominent similarities with the brain in terms of embryological origin, anatomical features and physiological properties.  The vascular and neuronal structure in the retina can now be visualized easily and non-invasively using retinal imaging techniques, including fundus photography and optical coherence tomography (OCT), and quantified semi-automatically using computer-assisted analysis programs. Studying the associations between vascular and neuronal changes in the retina and dementia could improve our understanding of dementia and, potentially, aid in diagnosis and risk assessment.  This protocol aims to describe a method of quantifying and analyzing retinal vasculature and neuronal structure, which are potentially associated with dementia. This protocol also provides examples of retinal changes in subjects with dementia, and discusses technical issues and current limitations of retinal imaging.

Impact of B-Scan Averaging on Spectralis Optical Coherence Tomography Image Quality before and after Cataract Surgery

Background and Objective

To determine optimal image averaging settings for Spectralis optical coherence tomography (OCT) in patients with and without cataract.

Study Design/Material and Methods

In a prospective study, the eyes were imaged before and after cataract surgery using seven different image averaging settings. Image quality was quantitatively evaluated using signal-to-noise ratio, distinction between retinal layer image intensity distributions, and retinal layer segmentation performance. Measures were compared pre- and postoperatively across different degrees of averaging.

Results

13 eyes of 13 patients were included and 1092 layer boundaries analyzed. Preoperatively, increasing image averaging led to a logarithmic growth in all image quality measures up to 96 frames. Postoperatively, increasing averaging beyond 16 images resulted in a plateau without further benefits to image quality. Averaging 16 frames postoperatively provided comparable image quality to 96 frames preoperatively.

Conclusion

In patients with clear media, averaging 16 images provided optimal signal quality. A further increase in averaging was only beneficial in the eyes with senile cataract. However, prolonged acquisition time and possible loss of details have to be taken into account.

The effect of cataract surgery on blue-yellow and standard-pattern visual-evoked potentials

PURPOSE

Blue-yellow visual-evoked potentials (BY-VEPs) may be used for diagnostics of functional ganglion cell damage in glaucoma and other ocular diseases. In this study we investigated the impact of lenticular opacities on BY- and standard pattern reversal VEPs by examining patients before and after cataract surgery.

METHODS

Eighteen patients with moderate cataract were included in a prospective study. Transient on/off isoluminant blue-yellow 2° checks were used for short-wavelength stimulation (BY-VEP), transient large 1° (M1) and small 0.25° (M2) black-white checks for standard pattern reversal VEPs. VEPs were acquired before (24 ± 30 days) and after cataract surgery (14 ± 16 days). The contralateral eye was used as a control.

RESULTS

Amplitude and latency of M1 and M2 peaks did not change significantly from before to after surgery. The amplitude of the BY-VEPs did not change significantly after cataract surgery (pre-surgery, -7.42 ± 3.43 μV, post-surgery, -7.93 ± 3.65 μV, p = 0.42), yet the latency of the main negative peak showed a significant decrease (pre-surgery, 143.9 ± 12.9 ms, post-surgery, 133.2 ± 7.7 ms, p = 0.0006). The BCVA improvement was significant from before to after cataract surgery (pre-surgery, 0.344 ± 0.125 LogMAR, post-surgery, 0.224 ± 0.179 LogMAR, p = 0.013) yet not correlated to the absolute decrease in latency of the BY-VEP after surgery (r = 0.309, p = 0.22). No significant changes were found in the contralateral eye.

CONCLUSIONS

The BY-VEP is sensitive to lenticular opacities of the human lens, presumably due to the increased short-wavelength absorption in the aging eye. This fact should be considered when applying BY-VEPs for diagnostics.