Correlation of SWAP (short wavelength automated perimetry) with OCT (optical coherence tomography in pre perimetric glaucoma

Purpose: To find out correlation of swap and OCT in preperimetric glaucoma patient coming to Dhiraj general hospital. Materials and Methods: A complete ophthalmological examination will be done including uncorrected and best corrected visual acuity, slit lamp examination, central corneal thickness measurement by pachymetry, applanation tonometry, gonioscopy and dilated fundus examination and Humphrey perimetry followed by SWAP and FDT. Result: In the present study a total of 50 patients were screened. Out of this 22 patients had a CDR of 0.5 with healthy neuro-retinal rim (HNRR) in both the eyes. One patient had 0.5 CDR with inferior thinning in both the eyes. 8 patients had a CDR of 0.6 with HNRR and 1 had 0.6 CDR with inferior thinning. 2 patients had a large cup to disc ratio of 0.7 CDR but the neuro retinal rim on clinical examination appeared to be healthy. 14 patients had a large cup to disc ratio of 0.7 in both the eyes. Out of this 8 had inferior thinning of the neuro-retinal rim and 6 had superior thinning of the neuro retinal rim. 2 patients included in this study had 0.8 CDR with one having superior thinning and one having inferior thinning of the neuro retinal rim. The accuracy of OCT in detecting even the smallest nerve fiber layer defect was much higher than seen on SWAP. About 52% showed normal OCT as compared to perimetry group which was 60% and about 48% of patients showed affected nerve fiber layer thinning as compared to perimetry where visual field changes were 40%. Conclusion: In this study it was concluded that SD-OCT is better in detection very early stages of glaucoma where SAP or SWAP modality of perimetry does not detect. The sensitivity of OCT is much higher than perimetry and can help in detecting the suspects of glaucoma. Patients at with high risk (family history, smokers, large cup to disc ratio etc) should be screen for both OCT and SWAP. This will help us for manage patients better as they will be detected at a very early stage.