Dr. Rashmi Nagar, Dr. Prabhat Nangia, Dr. Vinay Nangia
Suraj Eye Institute, Nagpur
A male, 35 years of age, came to our institute for follow up of primary open-angle glaucoma. His best corrected visual acuity was 6/6, N6 with a correction of -3.50 DS in both eyes. Slit lamp examination showed normal anterior segment. Intra-ocular pressure was 20 mmHg in both eyes. The patient had been prescribed the following anti-glaucoma medications – brimonidine, dorzolamide, timolol, netarsudil and travoprost eye drops, but he was non-compliant with them. His central corneal thickness was measured to be 528 microns in the right eye (RE) and 525 microns in the left eye (LE).
On dilated fundus examination vertical cup-disc ratio (VCDR) was noted to be 0.75 in the right eye with inferior rim thinning and 0.55 in the left eye.
Figure 1(a) – Colour fundus photograph of RE shows a VCDR of 0.75 with inferior rim thinning (red arrow).
Figure 1(b) – Colour fundus photograph of LE shows a VCDR of 0.55 (red arrow). Some Gunn’s dots are seen along the infero-temporal arcade (blue arrows).
Figure 3 – SD-OCT peripapillary retinal nerve fibre layer of the left eye shows mild loss of retinal nerve fibre layer in the temporal and supero-temporal sectors (red arrows).
Figure 4 – SD-OCT peripapillary retinal nerve fibre layer follow up scan of the right eye shows significant loss of retinal nerve fibre layer in the infero-temporal and supero-temporal sectors (red arrows), compared to the baseline scan over a follow up period of 6 months.
The progression of glaucoma is a well-documented occurrence in patients who fail to comply with their prescribed topical anti-glaucoma medication therapy. Unfortunately, our patient has been non-compliant with his medication regimen, resulting in a significant advancement of his glaucoma. Remarkably, within a mere 6-month time frame, the right eye has experienced rapid and severe damage to the retinal nerve fibre layer (RNFL). Of particular concern is the inferotemporal sector of the RNFL, which is known to be the most susceptible to glaucomatous damage. Previously, during the initial scan conducted in November 2022, this sector had only exhibited mild damage. However, in the follow-up scan, we observed a significant decrease in the RNFL thickness of the inferotemporal sector.
In the left eye, a similar observation was made. Comparing the current scan to the baseline scan from November 2022, we detected progressive thinning of the supero-temporal sector of the RNFL. This finding indicates a notable loss of the left eye’s RNFL over the past 6 months.
Another intriguing aspect of our patient’s condition is the relatively mild impact on the ganglion cell layer (GCL) despite the severe loss of RNFL. Surprisingly, there has been only a minimal change of -1 micron thickness in the GCL (Figure 5 and 7, red arrows) over the same 6-month period. In spite of the significant RNFL thinning over 6 months, it would appear that the GCL has been left untouched. This is so because in this patient, the RNFL loss skirts the central macular area, where there is the highest concentration of ganglion cells. Therefore the GCL heat and deviation maps do not show any significant loss. This is a classical case of preservation of the macular ganglion cells because the most vulnerable part of the RNFL in the lower half of the temporal segment and the upper part of the infero-temporal segment and their corresponding ganglion cells have been spared. What this may imply for the future is that our patient may continue to preserve his central vision even with significant superior and inferior glaucomatous damage and RNFL loss.
These findings underscore the critical importance of adhering to prescribed anti-glaucoma medication therapy to minimize the risk of glaucoma progression. The rapid and severe damage observed in both eyes, particularly in the inferotemporal and supero-temporal sectors, serves as a stark reminder of the potential consequences of non-compliance. It is imperative that our patient understands the significance of consistent compliant medical therapy to prevent further deterioration.
- Olthoff CM, Schouten JS, van de Borne BW, Webers CA. Noncompliance with ocular hypotensive treatment in patients with glaucoma or ocular hypertension: an evidence-based review. Ophthalmology. 2005 Jun 1;112(6):953-61.10.1016/j.ophtha.2004.12.035
- Lee WJ, Park KH, Seong M. Vulnerability zone of glaucoma progression in combined wide-field optical coherence tomography event-based progression analysis. Investigative Ophthalmology & Visual Science. 2020 May 11;61(5):56-.https://doi.org/10.1167/iovs.61.5.56
Dr Vinay Nangia
MS, FRCS, FRCOphth
Suraj Eye Institute
Email – email@example.com
Qn. 1. What sector of the retinal nerve fiber layer (RNFL) showed the most severe damage in the right eye on follow up?
Qn. 2. What was the change observed in the ganglion cell layer (GCL) over 6 months?
A. Severe thinning
B. Moderate thinning
C. Mild thinning
D. Minimal change
Qn. 3. What sector of the RNFL showed severe thinning in the left eye on follow up?
Qn. 4. What does the preservation of the GCL despite RNFL loss imply?
A. The patient will lose central vision
B. The patient may maintain central vision
C. The patient will become blind
D. The visual field loss will rapidly progress
Qn. 5. What is the main takeaway regarding the importance of glaucoma treatment compliance?
A. Compliance is not very important
B. Moderate compliance is sufficient
C. Strict compliance can prevent progression
D. Progression is inevitable despite compliance
Quizwise on factors associated with the progression of glaucoma
Qn. 1. Which factor is commonly associated with the progression of glaucoma ?
a. Dietary changes
b. Regular physical exercise
c. Compliance with medications
d. None of the above
Qn. 2. What is the most vulnerable sector of the RNFL for glaucomatous damage?
Qn. 3. Which of the following factors does not accurately identify patients at risk of non-compliance with their prescribed regimen?
a. Sociodemographic variables
b. Visual acuity (VA)
c. Old age
d. Knowledge of glaucoma
Qn. 4. Which dosing frequency is associated with greater noncompliance?
a. Once-daily regimen
b. Twice-daily regimen
c. More than twice daily regimen
d. No clear association with dosing frequency
Qn. 5. What is the role of brain-derived neurotrophic factor (BDNF) in the pathophysiology of glaucoma?
a) Triggering apoptosis in retinal ganglion cells
b) Inducing retinal neurodegeneration
c) Inducing synaptic and structural plasticity
d) Maintaining the survival retinal ganglion cells