# Ocular movement abnormalities and ptosis after glaucoma surgery: A retrospective decade long analysis

## TL;DR

This study found that ptosis and strabismus are rare but possible complications after glaucoma surgery, especially when muscle isolation is involved.

## Contribution

The study identifies muscle isolation surgery as the most likely to cause ptosis and strabismus after glaucoma procedures.

## Key findings

- Ptosis occurred in 3.7% of patients, with the highest incidence after muscle isolation surgery (5.7%).
- Strabismus occurred in 1.7% of patients and was most frequent after extraocular muscle manipulation (7.5%).
- Combined ptosis and strabismus occurred in 1.0% of patients, with higher prevalence after muscle isolation surgery (1.9%).

## Abstract

To evaluate the prevalence of ptosis, strabismus and the combination of both after glaucoma surgery and determine which kind of surgery is most likely to be linked to these complications.

A total of 705 clinical records of patients who underwent glaucoma surgery at the University Eye Clinic of IRCCS Ospedale Policlinico San Martino, Genoa, from January 1, 2010, to December 31, 2020, were retrospectively evaluated. Surgery procedures were divided in three groups: “Ab interno”, “Ab externo” and “Muscle isolation”.

Out of all patients 26 developed ptosis alone (3.7%), two developed bilateral ptosis, with a mean of 2.2 ± 1.08 procedures per patient. Highest incidence of ptosis was noticed in patients who underwent muscle isolation surgery (5.7%). Twelve patients developed strabismus alone (1,7%), four underwent unilateral surgery and eight bilateral surgery, with an average of 3.3 ± 1.78 procedures per patient. Strabismus was more frequent following extraocular muscle manipulation surgery (7.5%), showing a statistically significant difference (OR: 6.57; 95% CI: 1.71–21.65; p = 0.003) Seven patients developed both strabismus and ptosis (1.0%), one patient with bilateral ptosis. Four underwent bilateral surgery and three underwent unilateral surgery. The mean number of surgeries was 2.9 ± 1.07, showing a statistically significant difference compared to the uncomplicated glaucoma group (OR: 1.58; 95% CI: 1.01–2.25; p = 0.02). The prevalence of both ptosis and strabismus was higher after muscle isolation surgery (1.9%).

Ptosis, strabismus and the combination of both are rare complications after glaucoma surgery, mostly linked to surgery with muscle isolation.