A CASE PRESENTATION:
A male, 54 years of age, came with the blurring of vision in right eye since 6 months. His best corrected visual acuity was 6/6 partial in right eye and 6/6 in left eye. Anterior segment examination was normal.
Intraocular pressure was 34 mm Hg in right eye and 28 mm Hg in left eye. He was on brimonidine tartrate (0.2%) and timolol maleate (0.50 %) combination eyedrops since 3 years. Gonioscopy showed open angles in all quadrants in both eyes. His axial length in right eye was 23.04 mm and 23.21 mm in left eye. Central corneal thickness was 469 microns in right eye and 468 microns in left eye.
LEFT EYE
Impression: Patient presented to us with advanced glaucomatous damage in left eye with significant retinal nerve fiber layer and ganglion cell layer thinning in both eyes. The intraocular pressure in left eye was raised in spite of two anti-glaucoma medications. In view of the significant glaucomatous damage, the patient was also advised left eye trabeculectomy with mitomycin C. When one has a subject with significant RNFL loss, look for the segment where there is still some preservation of RNFL. This is the segment that should be followed up. See Fig 6b and 6d, where there is progressive RNFL thinning in the inferotemporal segment and it can be visualized, since there was some RNFL fiber still remaining, and enough to detect progressive loss.
Likewise when we see the GCL heat and deviation maps, we may only be able to see the expanding area of GCL loss specially when there it is less than 1 percentile value of the normative population. One may of course also continue to follow up the GCL macular segmental measurements. The relative preservation of the macular RNFL (see Hood’s report Fig 8 a and 8b) is important for vision but not so much for follow up. In such a situation though the macular RNFL will help if we were to do a macular visual field ( 10-2 or 12-2) which may in such a situation allow us to follow up this patient better.
Correspondence
Dr. Vinay Nangia
MS, FRCS, FRCOphth
Director
Suraj Eye Institute
Email – education@surajeye.org