Frequency doubling technology and standard automated perimetry in detection of glaucoma among glaucoma suspects.
BACKGROUND
Frequency Doubling perimetry (FDT) has been found to precede visual loss detected by standard automated perimetry (SAP) by as much as four years and the initial development of glaucomatous visual field loss as measured by SAP was found to occur in regions that had previously demonstrated abnormalities on FDT testing.


METHODS
A study on 55 glaucoma suspects (determined as per American Academy Guidelines, Preferred Practice Pattern, Oct 2010), was compared to 50 healthy participants (HP). Both glaucoma suspects and HP underwent SAP and FDT in random order. Only reliable fields were compared.


RESULTS
Mean deviation of FDT Matrix was significantly lower than SAP SITA in suspect and healthy group ; two devices showed significant correlation amongst both groups (suspects p = 0.002, healthy p = 0.011). Significant difference was found in PSD of SAP SITA and FDT Matrix (p = 0.001) in the glaucoma suspect group, PSD of FDT Matrix was significantly higher than PSD of SAP SITA in the healthy group (p < 0.001). PSD of SAP SITA significantly correlated with FDT Matrix PSD in glaucoma group (r = 0.579; p = 0.001) but no significant correlation found in healthy group (r = 0.153; p = 0.290). Percentages of normal test locations significantly higher in FDT Matrix compared to SAP SITA in glaucoma suspects and healthy participants.


CONCLUSIONS
FDT correlates well with SAP and may be used for patients who are unable to perform well and reliably with SAP but does not show any features of earlier glaucoma changes in this study.
Consultant (Ophthalmology), Base Hospital, Delhi Cantt, India.
Sagarika
S
Patyal
Director, AFMS (Med Research), O/o DGAFMS, Ministry of Defence, New Delhi, India ; Professor & Head, Dept of Community Medicine, Army College of Medical Sciences, New Delhi 11001, India.
Atul
A
Kotwal
ACAS, Med, O/o DGMS (AIR), New Delhi, India.
Ajay
A
Banarji
Professor & Head, Dept of Ophthalmology, Armed Forces Medical College, Pune-411040, India.
V S
VS
Gurunadh
Frequency doubling perimetry; Glaucoma suspects; Standard automated perimetry