Dr. Samyak Gupta, Dr. Prabhat Nangia, Dr. Vinay Nangia
Suraj Eye Institute, Nagpur
Case description
A 73-year-old male patient presented to our institute with a complaint of blurred vision. Upon examination, his best corrected visual acuity was 6/6, N6 in both eyes, and there were no abnormalities found during a slit lamp examination. However, his intraocular pressure was elevated, measuring 26 mmHg in the right eye and 22 mmHg in the left eye. A gonioscopic examination revealed open angles in both eyes, and his central corneal thickness was measured at 524μm in the right eye and 531μm in the left eye. Additionally, his axial length was recorded at 25.70 mm in the right eye and 25.42 mm in the left eye. In order to manage his intraocular pressure, he was prescribed Timolol 0.50% in both eyes.
Two years later, the patient returned for a follow-up visit, and his intraocular pressure was measured at 24mmHg in the right eye and 22mmHg in the left eye while on Timolol 0.50%. It was then decided to recheck his intraocular pressure without any medication. The patient was advised to discontinue the antiglaucoma medication and return after forty days. Upon his return, his intraocular pressure had increased to 28mmHg in both eyes, and the antiglaucoma medication was restarted. During a subsequent follow-up visit, the patient’s intraocular pressure remained elevated, measuring 28mmHg in the right eye and 26mmHg in the left eye. It was discovered that the patient was non-compliant with his medication.
Given the patient’s elevated intraocular pressure, he was advised to use a combination of brimonidine 0.2% and Timolol 0.50%. On his next follow-up visit after one month, his intraocular pressure was recorded at 18mmHg in the right eye and 17mmHg in the left eye. Visual field evaluation of both eyes was not reliable. It is important to note that the patient was also diagnosed with hypertension and ischemic heart disease, had undergone coronary artery bypass surgery, and was on anticoagulants.
Figure 1(a) – The colour fundus photograph of RE shows a vertical cup disc ratio of 0.5 (red arrow)
Figure 1(b) – The colour fundus photograph of LE shows a vertical cup disc ratio of 0.4 (red arrow). Epiretinal membrane noted at macula (yellow arrow)
Figure 3 – Baseline SD-OCT of parapapillary retinal nerve fiber layer shows normal thickness of RNFL (yellow arrows). (Year: 2017)
Figure 4 – Right eye OCT of parapapillary RNFL at follow-up showing normal RNFL thickness (yellow arrows) with no significant change in the RNFL thickness over a period of 6 years. (Year: 2023)
Figure 5 – Left eye OCT of parapapillary RNFL at follow up showing normal RNFL thickness (yellow arrows) with no significant change in the RNFL thickness over a period of 6 years.(Year: 2023)
| Discussion The patient under consideration was elderly, and his central corneal thickness (CCT) fell within the normal range for Central India, as determined by data from the Central India Eye and Medical Study. This study, which involved 4711 subjects and 9370 eyes, found the mean CCT to be 514±33μm. Similarly, the mean intraocular pressure (IOP) in the study was reported as 13.6±3.4mmHg. Notably, our patient did not have a family history of glaucoma. When confronted with an elevated IOP accompanied by an increased CCT, it is important to consider the possibility of “spurious ocular hypertension” rather than labeling it as ocular hypertension outright. This distinction is particularly relevant when the IOP elevation can be attributed to the increased CCT. The term ocular hypertension is more appropriately used when the central corneal thickness is normal, but the IOP exceeds the region’s normative data. Additionally, in cases of ocular hypertension, there should be no signs of damage to the optic nerve, retinal nerve fiber, or ganglion cell layer. In the context of our patient, we can classify him as a classical ocular hypertension case, as he exhibited an elevated IOP but had a normal optic disc. The significant risk factor present in his case was an increased axial length, which is known to predispose individuals to the development of glaucomatous damage. It is worth noting that while many studies have associated the degree of myopia (measured as spherical equivalent) with a higher risk of glaucoma, the underlying pathology is the elongation of the eye’s axial length. Determining whether to initiate treatment in such cases always poses a challenge. Classical patients like ours are rare to encounter, and conducting a long-term follow-up study with a larger cohort of similar subjects presents further difficulties. However, considering our patient’s increased axial length, elevated IOP, normal CCT, and age (73 years), we decided to initiate medical therapy and plan for long-term follow-up. It is important to mention that our patient exhibited non-compliance and inadequate control with a single therapy regimen. In conclusion, given the specific characteristics of our patient, including increased axial length, elevated IOP, normal CCT, and advanced age, we made the decision to commence medical therapy and undertake long-term follow-up. It is crucial to approach each case individually, considering various risk factors and clinical findings, in order to make informed treatment decisions. |
ReadWise
- Jonas JB, Nangia V, Matin A, Sinha A, Kulkarni M, Bhojwani K. Intraocular pressure and associated factors: the central India eye and medical study. Journal of glaucoma. 2011 Sep 1;20(7):405 https://doi.org/10.1097/ijg.0b013e3181f7af9b
- Nangia V, Jonas JB, Sinha A, Matin A, Kulkarni M. Central corneal thickness and its association with ocular and general parameters in Indians: the Central India Eye and Medical Study. Ophthalmology. 2010 Apr 1;117(4):705-10. https://doi.org/10.1016/j.ophtha.2009.09.003
- Ha A, Kim CY, Shim SR, Chang IB, Kim YK. Degree of myopia and glaucoma risk: a dose-response meta-analysis. American Journal of Ophthalmology. 2022 Apr 1;236:107-19. https://doi.org/10.1016/j.ajo.2021.10.007
- Kuzin AA, Varma R, Reddy HS, Torres M, Azen SP, Los Angeles Latino Eye Study Group. Ocular biometry and open-angle glaucoma: the Los Angeles Latino Eye Study. Ophthalmology. 2010 Sep 1;117(9):1713-9. https://doi.org/10.1016%2Fj.ophtha.2010.01.035
Correspondence
Dr Vinay Nangia
MS, FRCS, FRCOphth
Director
Suraj Eye Institute
Email – education@surajeye.org
QuizWise
Q1: Ocular hypertension includes:
A) Raised IOP
B) No RNFL loss
C) Normal visual field
D) All of the above
Q2: What are the risk factors for development of POAG in a case of ocular hypertension?
A) Age
B) Vertical cup disc ratio
C) Higher intraocular pressure
D) All of the above
Q3: Which condition can cause inaccurately low IOP?
A) Corneal edema
B) Corneal scar
C) Raised central corneal thickness
D) Thick mires
Q4: According to the ocular hypertension treatment study, which group had an increased risk of developing primary open-angle glaucoma?
A) Central Corneal Thickness of >588 microns
B) Central Corneal Thickness of >555 microns to < 588 microns
C) Central Corneal Thickness of < 555 microns
D) Central Corneal Thickness of > 655 microns