Evaluation Of Intraocular Pressure Measurements Using Tono-pen Avia In Central And Peripheral Part Of The Cornea Of Healthy And Glaucoma Patients

Abstract

 

Purpose:

 

To evaluate the difference in the central and peripheral (nasal & temporal) limbus intraocular pressure (IOP) measurements by using TONO-PEN AVIA tonometer in normal and glaucoma patients.

 

Methods:

 

IOPs of 32 healthy subjects and 32 consecutive glaucoma patients presenting to the outpatient department of our tertiary care institute were measured using TONO-PEN AVIA at the center of the cornea and at 2 mm distance from the nasal and temporal limbus along the horizontal meridian. The device displayed the average of 10 independent readings. Agreement between central and peripheral IOP measurements was evaluated.

 

Results:

 

Mean age of the normal individuals was 39.2 + 14.89 yrs, amongst which 58.4 % were males. The mean central IOP was 16.05 + 3.35 mmHg and the mean temporal & nasal limbal IOPs were 17.16 + 3.77 & 17.10 + 3.52 mmHg respectively. Nasal limbal pressures were in closer agreement with central pressures, than the temporal one (ICC= 0.753 vs 0.707). The nasal & temporal IOP were also in close agreement (ICC=0.746). Mean age of glaucoma patients was 43.2 + 15.32 yrs, amongst which 52.3 % were males. The mean central IOP was 24.06 + 1.91 mmHg and mean temporal and nasal limbal IOPs were 26.12 + 2.06 mmHg & 25.62 + 2.12 mmHg respectively. Nasal limbal pressures were in closer agreement with central pressures, than the temporal one (ICC= 0.956 vs 0.893). The nasal & temporal IOP were also in close agreement (ICC=0.924)

 

Conclusions:

 

Limbal IOP may need to be recorded in eyes with central corneal scarring. While either of the limbus may be used, nasal limbal recording of IOP may be a more reliable indicator of the true IOP.  

 

Keywords: clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • intraocular pressure