Spark ImageWise 53 – The Temporal Retinal Nerve Fiber Layer in Myopia

Dr. Shashank Somani, Dr. Sarang Lambat, Dr. Prabhat Nangia, Dr. Vinay Nangia 
Suraj Eye Institute, 559, New Colony, Sadar, Nagpur- 440001.

Case Description
A male, 23 years of age, presented with blurring of vision in both eyes since 1 month. On examination he is best corrected visual acuity (BCVA) was 6/9, N6 in right eye (RE) with correction of -5.25DS/+2.25DCx 85 and 6/6, N6 in the left eye (LE) with correction of -2.50DS/+1.50DCx 90. On slit lamp examination, BE anterior segment examination was normal. His intraocular pressure (IOP) was 12 mmHg in RE and 10 mmHg in LE. The axial length in RE was 24.14 mm and LE 23.39 mm. 


Figure 1: Colour fundus photograph of RE showing the vessels of superior and inferior arcade making a narrow angle with each other suggestive of a temporal drag of vessels (blue arrows). The distance between the two major veins is 2.86mm near the disc measured from the 3.4 mm RNFL circle scan and 14.87mm along the fovea (green dotted lines).
Figure 2: Colour fundus photograph of LE showing a relatively normal appearance of vessels of the arcade (blue arrows). Parapapillary atrophy can be seen on the temporal margin of optic disc (red arrow). The distance between the two major veins is 2.894mm near the disc (measured from the 3.4 mm RNFL circle scan) and 11.62mm along the fovea (green dotted lines).
Figure 3 – Shows significant thinning of RNFL in all the nasal sectors (red arrows in fig 3b and 3d) and increased thickness at  the temporal sector (blue arrows in fig 3b and 3d).  There is apparent thinning of the supero-temporal and inferotemporal segment RNFL (orange arrows in fig 3c) and significant thinning of the nasal sectors (black arrows in fig 3c). 
Figure 4 – Shows presence of reduced thickness of RNFL in the nasal sector (red arrows in fig 4b and 4d) and increased thickness in the IT sector and temporal sector (blue arrows in fig 4b and 4d). There is apparent thinning of the supero-temporal and inferotemporal segment RNFL (orange arrows in fig 4c) and significant thinning of the nasal sectors (black arrows in fig 4c). 
Figure 5 – Right eye RNFL thickness deviation map shows thickening of macular RNFL (black arrows) and thinning of superotemporal and inferotemporal RNFL (white arrows).
Figure 6 – Right eye EDI line scan through disc showing axonal thickening on the temporal side of the disc (green arrow). The anatomical disc margin is denoted by red arrow on the infrared photograph which coincides with the red arrow in OCT. 
Figure 7 – Left eye EDI line scan through disc showing axonal thickening on the temporal side of disc (green arrow). The anatomical disc margin is denoted by red arrow on the infrared photograph which coincides with the red arrow in OCT.
EyeCast – Listen to the discussion


Our patient is a myope. Myopes are highly predisposed to the possibility of developing glaucoma.  In myopes the assessment of   the optic disc is always difficult. This is specially so because changes in axial length are associated with a change  in  the shape of the optic disc, the origin of blood vessels, and the development of  parapapillary atrophy making  it difficult to identify glaucomatous changes, specially early  damage. In addition there may be a tilted optic disc, when the contours of the  neuroretinal  rim do not match those of  the normal optic disc. 

In our  patient,  one may see the presence of a parapapillary zone on the temporal side of the optic disc in both eyes  This is associated in the RE with  the vascular arcade  being drawn together  towards each other.  i.e. the distance  between the  superior temporal and inferior temporal vessels  is   much less than one would expect.  We have drawn and measured the distance  between the veins  at the 3.4 mm circumference   of the RNFL scan. The RE shows a smaller distance compared to the LE. 

Measurement of the RNFL using the 3.4 mm scan centered on the optic disc showed in the RE  significant higher RNFL values of 236 microns,  whereas the normal values would be about 77 microns.   We believe the reason for this is the  coming together of the blood vessels which are seen to arise from the optic disc with a relatively more acute angle than in normal eyes.  There is also an apparent thinning  of the superotemporal and inferotemporal  RNFL  values. The blue arrow in Fig 3 b shows  the  temporal area of RNFL  which is thickened.   The left eye also shows thickened macular RNFL. 

In patients with a gamma zone one often  finds  a somewhat thickened macular RNFL.  This may have something to do with the  alteration of the temporal area of the optic disc neuroretinal rim and parapapillary area.   However this association is seen more often in patients with  a significantly increased axial length.  The axial length in our patient was RE 24.14 mm.  and LE 23.39 mm.  In our patient,  we also looked at the RNFL scans taken with the Bruch’s Membrane opening  reference, however the results were no different.  Although  clinically there is an appearance that a gamma zone would be present, the OCT did not  confirm this. 

Fig 5 shows a deviation map of the RNFL and the thickening of the RNFL  (black arrows) along with  thinning of the  superotemporal and inferortemporal areas, was  evident. 

On  enhanced depth imaging of the optic nerve we  found that in both eyes. Fig 6 b and figure 7 b. there was axonal thickening  ( green arrows) which represents the macular RNFL. 

The point to consider is that one may not diagnose these eyes to be glaucomatous, because of the superotemporal and inferotemporal thinning of the RNFL in the RE.  It is questionable whether the presence of apparent thickening of the macular segment in the RE and the macular and inferotemporal segment of the LE would be protective  from glaucoma, specially with regard to preserving the  central field of vision

In the assessment of RNFL in myopia it is important  to consider the position of the blood vessels, the size of the optic disc,  the presence of parapapillary changes and  the tilt of the optic disc. These influence the RNFL thickness  and may present with RNFL thinning in different segments depending on the optic  disc related changes, even though there is no glaucoma.  Therefore  using RNFL in assessing for glaucoma must be associated with follow up scans and observation of the changes in the optic disc.  The ganglion cell layer would also be useful in these situations, when the axial length is not so much as to prevent a good quality GCL scan.  The clinical appearance of the optic disc and the intraocular pressure  are important  in  assessing and in the follow up of  glaucoma in myopia. All other diagnostic procedures may be used as indicated and the implications of the test results much be understood. 


  1. Chen JJ, Kardon RH. Avoiding Clinical Misinterpretation and Artifacts of Optical Coherence Tomography Analysis of the Optic Nerve, Retinal Nerve Fiber Layer, and Ganglion Cell Layer. J Neuroophthalmol. 2016 Dec;36(4):417-438. doi: 10.1097/WNO.0000000000000422.
  2. Hwang YH, Yoo C, Kim YY. Myopic optic disc tilt and the characteristics of peripapillary retinal nerve fiber layer thickness measured by spectral-domain optical coherence tomography. J Glaucoma. 2012 Apr-May;21(4):260-5. doi: 10.1097/IJG.0b013e31820719e1.

Dr Vinay Nangia
Suraj Eye Institute
Email –


Q. 1 – Which of the following about the optic disc in myopia is correct. 

  1. All optic discs in myopes  are larger than normal
  2. The optic disc in myopia  is always different from a normal optic  disc. 
  3. Gamma one is frequently found in myopia
  4. Beta zone is found more commonly in myopia

Q. 2 – Which of the following is false for the  retinal nerve fiber layer in myopia. 

  1. The RNFL may show macular thickening.
  2. The RNFL may show nasal thinning.
  3. The RNFL thinning is always associated with glaucoma in myopia
  4. When the RNFL circle passes over the area of gamma zone  the RNFL measurement may not be accurate

You cannot copy content of this page

× Hello!
%d bloggers like this: