Study finds, the association between Intraocular Pressure an
IOP increases are associated with worsening medial deviation in mild/suspicious glaucoma treated eyes once IOP hits the 20s. IOP increases are related with poorer VF performance in moderate/advanced eyes throughout the IOP range.

A Study was conducted to describe the relationship between mean treated intra-ocular pressure (IOP) and visual field (VF) worsening and understand how this relationship is affected by glaucoma severity and IOP range.

1446 eyes of 869 treated glaucoma patients with at least five longitudinal reliable VF tests and IOP measures were included. Mixed-effects linear models were employed to understand the effect of eye-specific mean treated IOP on mean deviation (MD) slope. Models included interaction terms to assess the differing relationships between MD slope and mean IOP by glaucoma severity (suspect/mild vs. moderate/advanced) and splines to account for the differing effects of mean IOP on MD slope at different IOP ranges (above or below 21mmHg).

--In suspect/mild glaucoma, when treated IOP values were less than 21 mmHg, a 1 mmHg increment in IOP was not associated with an increase in the rate of VF worsening but when treated IOP values rose above 21 mmHg, a 1 mmHg increment in IOP was associated with faster VF worsening.

--In moderate/advanced disease, a 1mmHg increment in treated IOP was associated with faster VF worsening both below and above 21 mmHg, but the effect was much more pronounced in the higher range.

Finally, IOP was connected to worsening of the more advanced glaucoma in the eyes throughout the IOP range but solely to deterioration of eyes with less serious glaucoma in the higher IOP range.