Posters

Comparison of different methods of intraocular pressure measurements by Goldmann applanation tonometry, air-puff tonometry, and ocular response analyzer following intrastromal corneal ring segments implantation

Poster Details

First Author: M.Fakhry Khattab EGYPT

Co Author(s):    M. El-Basty   M. El-Shazly   M. ElFwwal              

Abstract Details

Purpose:

Intrastromal corneal ring segments (ICRS) implantation is an additive surgical procedure for keratoconus correction, measurement of intraocular pressure (IOP) is fundamental to the diagnosis and management of glaucoma. There are different tonometers present, Goldmann applanation tonometry (GAT) is generally regarded as the reference standard. The presence of ICRS makes IOP measurements using GAT difficult, due to the affection of corneal curvature, corneal elasticity and tear film distribution. The study aimed to compare different IOP readings after ICRS implantation taken by the three different tonometers and to correlate central corneal thickness to IOP measurements taken.

Setting:

Cairo University Hospital, Kasr Alainy.

Methods:

An Observational Cross-sectional analytic study included patients who underwent ICRS keraring implantation for more than three months. In each eye, the two rings were placed using the femtosecond laser assisted technique 5.5 mm or 6 mm from the center. IOP was measured using three different tonometers; GAT, air-puff tonometer and ocular response analyzer (ORA) corneal-compensated IOP (ORA-IOP cc).

Results:

One hundred and ten eyes of 110 patients (61 males and 49 females) aged 27.56 ± 6.38 years were included. IOP measurements by GAT, air-puff tonometer, and ORA-IOP cc were 13.28 mmHg ± 2.13, 10.47 mmHg ± 2.55 and 13.19 mmHg ± 2.78 respectively. Comparisons between air-puff and each of GAT and ORA-IOP cc were statistically highly significant (p<0.001). Comparison between the 3 tonometers was also statistically highly significant (p<0.001).

Conclusions:

IOP measurements taken by air-puff tonometer were significantly lower than those taken by GAT and ORA-IOP cc, these differences were not constant across the pressure range but increased as the pressure values determined using GAT and ORA increased. ORA-IOP cc and GAT showed similar readings. No correlation was found between any of the IOP readings taken by the 3 tonometers and the central corneal thickness.

Financial Disclosure:

None