Posterior synechia formation after phacovitrectomy - Predicting factors and the role of short-acting mydriatics.

PURPOSE: To evaluate the influence of topical short-acting mydriatics on the formation of posterior synechia after phacovitrectomy surgery of pars plana vitrectomy and phacoemulsification with intraocular lens implantation. METHODS: A prospective randomised controlled trial. Fifty-seven adult (>18 years old) patients (57 eyes) who underwent phacovitrectomy surgery at a single tertiary hospital, were randomly divided into two groups. The control group (29 eyes) received standard postoperative treatment (topical antibiotics and steroids). The study group (28 eyes) received short-acting mydriatics together with standard therapy. Patients were followed until 24 months after surgery. The primary outcome measure was the formation of posterior synechia during the follow-up period. RESULTS: A total of 7 patients developed posterior synechia during the follow-up period (12%), 3 in the study group (11%) and 4 in the control group (14%). There was no statistical difference between the groups. Significant associations for the development of posterior synechia were surgery for retinal detachment, longer surgery duration (>93 min) and the use of tamponade, in particular silicone oil. CONCLUSIONS: The use of topical short-acting mydriatic drops after phacovitrectomy surgery, in addition to standard post-operative treatment, did not reduce the formation of posterior synechia. However, we identified several factors that may influence or act as predictors for the development of posterior synechia: surgery for retinal detachment, using silicone oil tamponade and a longer surgery duration. Our findings may aid in the standardisation of post-phacovitrectomy surgery treatment and define potential at-risk patients who should be monitored more closely.

Incidental Unilateral Macular Lesions in Children.

BACKGROUND: This study aims to examine the rare entity of unilateral macular lesions in the pediatric population and describe the distinct diagnoses and characterizations related to these findings. METHODS: A retrospective cohort design. The database of the ophthalmology clinic in a tertiary medical center was reviewed to identify all children with incidental unilateral macular findings, examined during 2016 through 2021. RESULTS: Twenty children were included. Mean age was 7.8 ± 3.4 years, 50% were girls. The most common macular lesion was torpedo maculopathy (50%), followed by pigmentary changes (25%), discoid maculopathy (15%), macular scar and combined hamartoma of the retina and retinal pigment epithelium (RPE) (5% each). None of the lesions changed after a mean follow-up duration of 2.3 ± 1.5 years. Visual acuity in the involved eye was equal to that in the contralateral eye in 90% of patients and did not change from initial to final visit. CONCLUSION: Incidental unilateral macular lesions in the pediatric population are usually benign, stable, and do not affect vision. Long-term follow-up is advised, as vision-threatening alterations may appear. [Ophthalmic Surg Lasers Imaging Retina 2023;54:346-352.].

Figure-ground processing during fixational saccades in V1: indication for higher-order stability.

In a typical visual scene we continuously perceive a "figure" that is segregated from the surrounding "background" despite ongoing microsaccades and small saccades that are performed when attempting fixation (fixational saccades [FSs]). Previously reported neuronal correlates of figure-ground (FG) segregation in the primary visual cortex (V1) showed enhanced activity in the "figure" along with suppressed activity in the noisy "background." However, it is unknown how this FG modulation in V1 is affected by FSs. To investigate this question, we trained two monkeys to detect a contour embedded in a noisy background while simultaneously imaging V1 using voltage-sensitive dyes. During stimulus presentation, the monkeys typically performed 1-3 FSs, which displaced the contour over the retina. Using eye position and a 2D analytical model to map the stimulus onto V1, we were able to compute FG modulation before and after each FS. On the spatial cortical scale, we found that, after each FS, FG modulation follows the stimulus retinal displacement and "hops" within the V1 retinotopic map, suggesting visual instability. On the temporal scale, FG modulation is initiated in the new retinotopic position before it disappeared from the old retinotopic position. Moreover, the FG modulation developed faster after an FS, compared with after stimulus onset, which may contribute to visual stability of FG segregation, along the timeline of stimulus presentation. Therefore, despite spatial discontinuity of FG modulation in V1, the higher-order stability of FG modulation along time may enable our stable and continuous perception.