Prevalence and Visual Outcome of Glaucoma With Uveitis in a Thai Population
Glaucoma secondary to uveitis is an important comorbidity of the disease condition and is the second most common cause of vision loss in adults secondary to uveitis.
The study by Pathanapitoon et al1 is an interesting read that has addressed the prevalence of uveitic secondary glaucoma in a Thai population along with the associated risk factors.
In the methodology, however, there are few points that we would like to emphasize. Firstly, the authors have not mentioned about the gonioscopic status of the patients. Gonioscopy is an integral part of any glaucoma evaluation and diagnosis.2 In uveitis, the angle details can present in varied forms. In acute uveitis, the cause of raised intraocular pressure (IOP) is usually the blockage of the trabecular meshwork with inflammatory cells and turbid aqueous, whereas, in recurrent and chronic cases, the cause is usually progressive synechial angle closure. In the previous entity, one can expect the IOP to come down with the resolution of the uveitic process, whereas, if the IOP rise is caused by the peripheral anterior synechiae formation involving >180 degrees, the patients might need long-term medications and ultimately surgery. Hence, diagnosis and differentiation are often made on the basis of gonioscopic findings. Therefore, in our view, gonioscopy was one of the main procedures that should have been included, especially when risk factors associated with the development of secondary glaucoma were being assessed.
Second, the lens status of the subjects has not been mentioned by the authors. The vision loss in uveitic secondary glaucoma can also be attributable to the development of complicated cataract that can lead to vision loss at presentation and follow-up. The incidence of cataract in uveitis varies from 57% in pars planitis3 to 78% in Fuchs heterochromic iridocyclitis.4
Third, optic disc and retinal nerve fiber layer assessment in uveitic eyes sometimes are a challenge, as the view can be precluded because of the formation of posterior synechiae and complicated cataract. The authors, however, have not mentioned the examination error that can occur because of the hazy view.
The authors have rightly highlighted that the cause of increased IOP in the 60 years and above age group can be attributable to the already compromised outflow system. The authors have mentioned that the onset of glaucoma from the start of the disease process was 46 months. From this, we understand that the cause of the gradual rise of the IOP can be attributable to the synechiae formation. Moreover, the recurrence in these patients has not been mentioned, as it can greatly affect the trabecular meshwork function because of various reasons, as mentioned above.
Hence, we would like to conclude that, in the factors affecting IOP, the authors should have included the angle status while determining the cause for high IOP.