Analysis of foveal angle after successful VMT detachment.

Abstract

Purpose : Vitreomacular traction (VMT) is characterised by posterior vitreous detachment, accompanied by distortion of the fovea. Ocriplasmin is a proteolytic enzyme thought to cleave the components of the vitreoretinal interface. We investigate anatomical change at the fovea after successful detachment and assess symptoms.

Methods : A single centre retrospective study was performed on all patients treated for VMT using Ocriplasmin. A pilot study of patients with good corrected vision and healthy fundi was carried out to ascertain the normal variation in foveal dip. 63 patients had received treatment for VMT since 2014. 21 were confirmed to have had sucessful detachment on OCT scan and 23 were identified with co-pathology of macular degeneration, hole or edema.
Patient demographics were obtained from electronic notes, then patients were grouped and analysed using Image J software. 3 patients were discarded for lack of comparable data.

Results : The pilot study revealed the angle of foveal dip to vary between individuals, ranging between 125 and 161degrees(⁰), with mean 140⁰. Angle between fellow eyes only varied by a maximum of 5^0.
Average age of treated patients was 75years, with equal numbers of male and female. No relationship between age and foveal angle was identified, however there was a positive correlation between age and success of treatment.
Of the 21 patients with successful posterior vitreous detachment(PVD) on OCT the resultant angle averages 141^0, matching the values of pilot disease free eyes. Patients with pathology averaged 34⁰ improvement of angle while those without gained 50⁰.Inter-patient variation was large (SD=54 each,p=0.038). Those with unsuccessful PVD had a smaller 23⁰ difference between affected and control eye (SD=17). There was no defined relationship between visual gain and change in angle in the groups with or without co-pathology.
Incidentally we identified the 'inverse nipple' sign on contour map in all cases of VMT, which resolved after treatment.
We also found that 50% of patients showed improved vision without complete PVD.

Conclusions : To our knowledge this is the first report of foveal angle measurement in relation to macular conditions. VMT makes foveal angle less acute and affects vision. Inverse nipple sign is useful in cases where vitreous base is difficult to identify. Foveal angles have the potential to be utilised as an aide to assessing function and monitoring disease in a variety of macular conditions.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.