Evaluation of Intraocular Pressure Following a Vitreoretinal Surgery Using Goldmann Applanation Tonometry, Icare and Accupen

Goldmann applanation tonometry (GAT), used since 1948, is the reference technique for measuring intraocular pressure (IOP) in both healthy patients and those suffering from glaucoma or other eye disorders. However, the use of GAT requires the topical application of fluorescein, local anesthesia, and direct contact with the cornea. In addition to its lack of portability, these characteristics of GAT quickly led clinicians to try to find simpler, less cumbersome, but just as reliable techniques to measure IOP. Among the techniques developed to potentially replace GAT, two portable techniques are particularly easy to use: rebound tonometry (Icare) and portable applanation tonometry (Accupen). Before these techniques are universally and interchangeably used with GAT, their reliability and accuracy must be measured. The majority of studies have evaluated these techniques in glaucomatous or healthy eyes, presenting mixed but promising results. However, only one recent study has evaluated the validity of the two techniques (Icare and TonoPen) in a post-operative context of vitreo-retinal surgery. More data is therefore necessary to come to a definitive conclusion regarding the reliability of Icare and Accupen.

The objective of this study is therefore to determine whether the IOP measured by Accupen and/or Icare is as accurate as that taken by GAT in patients who have undergone vitreo-retinal surgery.

To answer this question, this project will be a prospective controlled study of 67 patients who have undergone vitreo-retinal surgery and who will have their intraocular pressure taken 1 day post-operatively by the 3 instruments mentioned above, in a randomized order. At their 1-day post-operative visit, an ocular medical history will be taken, including the preoperative diagnosis and the type of surgery performed. A resident in ophthalmology at Laval University, will take a series of 2 intraocular pressures with these 3 devices: GAT, Icare, and Accupen and will average for each group.

The project research hypothesis would be that the taking of intraocular pressure by Icare and/or Accupen is as valid as that taken by Goldman's applanation tonometry.

Inclusion criteria

• Age ≥ 18
• Received a vitreoretinal surgery

Exclusion criteria

• Corneal dystrophy
• Corneal surgery (penetrating keratoplasty, DSAEK/DMEK less than 6 months, radial keratotomy)
• Irregular corneal surface
• Active corneal ulcer
• Active epithelial deficit
• Central corneal scarring
• A history of scleral buckle