Abstract
Abstract: :
Purpose: A new ophthalmodynamometric (OD) technique utilizing a Goldmann contact lens fitted with a pressure senor has been used to document an increased central retinal vein collapse pressure (CRVCP) in eyes with chronic open angle glaucoma (COAG) compared to a control group with cataract or refractive problems. Another study showed that the OD force required to induce venous pulsation using a traditional ophthalmodynamometer is increased in glaucoma and is associated with more severe visual field (VF) loss. The present study seeks to determine the CRVCP in glaucoma suspects with asymmetrical cup–to–disc ratios (ACTDR) using a Goldmann contact lens ophthalmodynamometer. This may help determine if one or both eyes are at risk for developing VF changes in the future. Methods: The retrospective clinical study included 10 eyes of 5 subjects with ACTDR. After topical anesthesia, a Goldmann contact lens fitted with a pressure sensor in its holding grip was placed on the cornea. Pressure was applied to the globe with the contact lens and pressure values in relative units (ru) were recorded when the central retinal vein started pulsating. Intraocular pressures (IOP) corrected for corneal thickness were reviewed to determine if the IOP was greater in eyes with a larger CTDR. Finally, the VF exams of all patients were reviewed. Results: The mean CRVCP was 14.7 ru (SD=8.35) in eyes with a larger CTDR and 11.5 ru (SD=5.42) in eyes with a smaller CTDR (p=0.492). The mean IOP after correcting for corneal thickness was 14.7 mm Hg in both groups (SD=3.19 for larger CTDR and 2.94 for smaller CTDR; p=0.992). The VF exams of all patients were within normal limits. Conclusions: As measured with a new ophthalmodynamometer, CRVCP measurements were increased in both eyes of glaucoma suspects with ACTDR as compared to a previously documented control group with cataract or refractive problems (6.1 ru). The CRVCP was higher in eyes with a larger CTDR (not statistically different). Compared to eyes with COAG (26.1 relative units), these patients may have a moderately increased risk of developing glaucomatous VF changes in the future. The IOP was in the low–normal range and not significantly different between glaucomatous and normal appearing eyes, indicating that CTDR changes may have developed independent of IOP. VF exams for all patients were normal. This technique may help identify glaucoma suspects with ACTDR who are truly at risk for glaucomatous VF changes versus those who have normal anatomical variations in the appearance of the disc and are unlikely to develop VF changes.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • optic flow