25th RCOphth Congress, President's Session paper: 25 years of progress in vitreoretinal surgery

Incidence of Sympathetic Ophthalmia after Intraocular Surgery: A Systematic Review and Meta-analysis

TOPIC

Sympathetic ophthalmia (SO) is a rare bilateral granulomatous panuveitis that can present after trauma or intraocular surgery (IOS). The incidence of SO after IOS varies among studies. The purpose of this review was to determine the incidence proportion of SO after IOS.

CLINICAL RELEVANCE

The incidence proportion of SO after IOS can provide physicians and patients with information on the risk of SO during the consent process before surgery.

METHODS

In this systematic review and meta-analysis, MEDLINE, EMBASE, and Cochrane databases were searched from inception to January 1, 2023 for population-based studies of SO after IOS. Two reviewers independently screened the results. Random-effects meta-analyses calculated incidence proportion. Subgroup analysis assessed SO incidence based on IOS type and technological advancements. Study quality and bias were assessed using the Newcastle-Ottawa scale and the Grades of Recommendation, Assessment, Development, and Evaluation framework.

RESULTS

The final meta-analyses included 19 studies, with 118 cases of SO occurring after 505 178 inciting events. The estimated overall incidence proportion of SO after IOS was 0.061% (95% confidence interval [CI], 0.033%-0.111%; I2 = 83%), and the estimated incidence rate was 9.24 cases per 100 000 person-years (95% CI, 4.03-21.19; I2 = 88%). The average study duration across these studies was 10.8 years. Within the reviewed literature, SO after glaucoma and vitreoretinal IOS was studied most, with 9 and 6 studies, respectively. Observed differences in incidence between glaucoma (0.098%; 95% CI, 0.042%-0.232%; I2 = 40%) and vitreoretinal (0.043%; 95% CI, 0.022%-0.085%; I2 = 88%) IOS were not statistically significant (P = 0.14). Also, no significant difference was found in the incidence proportion before and after 1975, when modern intraocular surgical techniques emerged (0.060% vs. 0.058%; P = 0.98). The outcome measures showed low-certainty Grades of Recommendation, Assessment, Development, and Evaluation evidence.

DISCUSSION

Sympathetic ophthalmia after IOS is rare and might not have changed over the past 5 decades. The estimated incidence proportion of SO may be useful during the consent process before surgery. Also, no significant difference may exist in the incidence of SO between glaucoma and vitreoretinal IOS, based on low-certainty evidence.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Vitreoretinal Surgery with Temperature Management: A Preliminary Study in Rabbits

The present study aimed to evaluate the structure of the rabbit retina after vitreoretinal surgery using prolonged irrigation with solutions of different temperatures. Thirty-six rabbits (72 eyes) were included in this study and randomly divided into 3 equal groups according to the temperature of the intraocular irrigating fluid they received during vitrectomy. Vitreoretinal surgery was performed with a 5°C irrigation solution in group 1 (12 rabbits, 24 eyes), a 22°C irrigation solution in group 2 (12 rabbits, 24 eyes), and a 36°C irrigation solution in group 3 (12 rabbits, 24 eyes). In each group of animals, the mean irrigation/aspiration time was 30 minutes for left eyes and 60 minutes for right eyes. Histological examination of the retina was performed 1, 7, and 30 days after surgery. During surgery, the temperature in the vitreous cavity of the eyes of rabbits of groups 1, 2, and 3 dropped by 26.0°C, 11.2°C (deep hypothermia), and 1.0°C (mild hypothermia), respectively. The highest rewarming rate was detected in group 1 (0.9°C/min) compared with group 2 (0.7°C/min) and group 3 (0.2°C/min). After 60 minutes of irrigation, retinal structural changes were detected in the animals of groups 1 and 2 (in contrast to the animals of group 3). After surgery with irrigation lasting 30 minutes, no retinal structural changes were observed. This study showed that temperature management, avoidance of intraoperative deep hypothermia, and prevention of rapid uncontrolled rewarming may protect the retinal morphology and increase the safety of prolonged vitreoretinal surgery.

Outcomes of pars plana vitrectomy following ocular trauma at varying surgical time points

Background

The optimal timing of pars plana vitrectomy (PPV) following ocular trauma is an ongoing debate. Early vitrectomy post-trauma enables the rapid assessment of retinal disease by removing the scaffold that fosters proliferative vitreoretinopathy. On the other hand, late vitrectomy is less challenging as there is a lower risk of bleeding and posterior vitreous detachment induction is easier. The purpose of this work is to report the functional and anatomical outcomes following ocular traumatic injuries in a United States-based cohort, emphasizing the time of intervention.

Methods

This was a retrospective case series of 110 patients with traumatic ocular injuries who underwent PPV between 2008 to 2020. Patients were grouped into four timing categories: same day (0 days), early (1–7 days), delayed (8–14 days), and late (> 14 days). Multivariable regression models controlling for confounding were implemented to assess the impact of vitrectomy timing on anatomical and functional outcomes. Visual acuity (VA) at baseline and after surgery, proliferative vitreoretinopathy (PVR), and enucleation for each vitrectomy timing category were recorded.

Results

Patient demographics and severity of ocular trauma were comparable across timing categories. Final VA in LogMAR was found to have a stepwise worsening as the time of ocular trauma to vitrectomy was increased (p < 0.05). For every one-step increase in the vitrectomy timing category, there was an adjusted 0.24 (CI 0.04–0.44) increase in final VA. No patient in the same day vitrectomy group had an enucleation or PVR, while patients who had late vitrectomies had the largest number of both enucleations and PVR (44.4% and 52.0%, respectively). In adjusted analysis, there was 3.11 increased odds (CI 1.03–9.42) of developing PVR for a one-step increase in vitrectomy timing (p < 0.05).

Conclusion

Vitrectomy on the same day of injury has the best final VA, and the lowest incidence rates of PVR and enucleation in comparison to other timing categories, regardless of etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40942-022-00399-9.

Optimal timing of vitrectomy for severe mechanical ocular trauma: A retrospective observational study

Mechanical ocular trauma could lead to disastrous visual outcomes. There has been a controversy regarding the timing of vitrectomy for such cases. This study aimed to find out the optimal timing of vitrectomy for severe mechanical ocular trauma. Patients with severe mechanical ocular trauma who had undergone vitrectomy were enrolled and followed up for at least 6 months. Clinical data were collected including ocular trauma score (OTS), the timing of vitrectomy upon injury, visual acuity, vitrectomy results, post-operation complications and etc. All cases were classified according to the timing of vitrectomy upon injury into 3 groups: group A 1–7 days, group B 8–14 days, group C more than 14 days. A total of 62 cases were enrolled, including 20 eyes in group A, 25 eyes in group B, and 17 eyes in group C. No significant differences were shown of the gender, age or OTS among the 3 groups. Both functional success rate and visual outcome were optimal in group B, then in group A, and worst in group C. These results suggested that the best timing of vitrectomy for severe mechanical ocular trauma is 8–14 days upon injury; second best is 1–7 days; worst is after 14 days.

Subretinal surgery: functional and histological consequences of entry into the subretinal space

BACKGROUND AND OBJECTIVES

Gene-therapy, stem-cell transplantation and surgical robots hold the potential for treatment of currently untreatable retinal degenerative diseases. All of the techniques require entry into the subretinal space, which is a potential space located between the retina and the retinal pigment epithelium (RPE). Knowledge about obstacles and critical steps in relation to subretinal procedures is therefore needed. This thesis explores the functional and histological consequences of separation of the retina from the RPE, extensive RPE damage, a large cut in the retina (retinotomy) and RPE phagocytosis in a porcine model.

METHODS

Experiments were performed in 106 female domestic pigs of Danish landrace distributed over five studies. Under general anesthesia, different procedures for expansion of the subretinal space were conducted. Outcomes were visual function measured electrophysiologically with multifocal electroretinogram (mfERG) and retinal morphology examined histologically. Study I: The effect of anesthesia on mfERG was examined by repeated recordings for 3 hr in isoflurane or propofol anesthesia. Outcome was mfERG amplitude. Study II: Consequences of a large separation of the photoreceptors from the RPE were examined by injecting a perfluorocarbon-liquid (decalin) into the subretinal space. Two weeks after, in a second surgery, decalin was withdrawn. Outcomes were mfERG and histology 4 weeks after decalin injection. Study III: Extensive RPE damage was examined by expanding the subretinal space with saline and removing large sheets of RPE-cells through a retinotomy. Outcomes were mfERG and histology 2, 4 and 6 weeks after the procedure. Study IV: Consequences of a large retinotomy were examined by similar procedures as in Study III, but in study IV only a few RPE cells were removed. Outcomes were mfERG and histology 2 and 6 weeks after surgery. Study V: Clearance of the subretinal space was examined by injecting fluorescent latex beads of various sizes into the subretinal space. Outcome was histologic location of the beads at different time intervals after the procedure.

RESULTS

Study I: MfERG amplitudes decreased linearly as a function of time in propofol or isoflurane anesthesia. Duration of mfERG recording could be decreased without compromising quality, and thereby could time in anesthesia be reduced. Study II: MfERG and histology remained normal after reattachment of a large and 2-week long separation of the photoreceptors and RPE. Repeated entry into the subretinal space was well tolerated. Fluid injection into the subretinal space constitutes a risk of RPE-damage. Study III: Removal of large sheets of retinal pigment epithelial cells triggered a widespread rhegmatogenous-like retinal detachment resulting in visual loss. Study IV: A large retinotomy with limited damage of the RPE was well tolerated, and visual function was preserved. Study V: Subretinal latex beads up to 4 μm were phagocytosed by the RPE and passed into the sub-RPE space. Beads up to 2 μm travelled further through the Bruch's membrane and were found in the choroid, sclera and inside blood vessels.

CONCLUSION

A large expansion of the subretinal space, repeated entry, a large retinotomy and limited RPE damage is well tolerated and retinal function is preserved. Subretinal injection of fluid can damage the RPE and extensive RPE damage can induce a rhegmatogenous-like retinal detachment with loss of visual function. Foreign substances exit the subretinal space and can reach the systemic circulation.