Don’t Overlook The Secondary Glaucomas
By: Paul M. Karpecki, OD, FAAO
Clinical Director – PECAA
Once PXF present it can cause the IOP to elevate dramatically and rapidly progress to glaucoma (PXG). PXG has faster rates of progression to visual field loss, is less responsive to therapeutics and typically requires surgical intervention.1
The initial presentation of PXF is a whitish protein that deposits on the anterior capsule of the crystalline lens (and since it’s a systemic condition deposits on other tissues in the body). Interestingly it is also been associated with a higher incidence of hearing loss and Alzheimer’s Disease.2,3 It can also deposit on the endothelium which can be observed via specular microscopy. But the key observation is that of the anterior lens capsule where it looks like grayish-white flakey material, rolled edges and most often located in the periphery of the lens or pupillary margin area.
So is you happen to make a diagnosis of PXF, usually observed when performing a dilated pupil examination, you should immediately work up the patient for glaucoma and of course pay strict attention to IOP, which can elevate rapidly. Patients with this diagnosis should be seen at least every 6 months (or sooner if early signs of potential glaucoma may be present). Ultimately about 50% of patients with PXF go on to develop PXG likely due to the material depositing in the trabecular meshwork and obstructing aqueous outflow.
As with other secondary glaucoma forms the time intervals are much shorter to progression and prognosis is worse than that of primary open angle glaucoma.
A second case involved a young (mid 30s on initial visit), moderately myopic male patient, who was examined by various doctors in a group practice of optometry. In his 5 visits over 7 years, IOP was measured three times and omitted twice. The original IOP measurement on his first visit was 18 mmHg OD and 19 mmHgOS. The second visit had no IOP noted and same for the third. The fourth visit measured 23 and 26 without examining the optic nerve and the fifth visit, which resulted in a referral to a glaucoma specialist, was 26 OD and 38 OS. Optic nerve evaluation and fundoscopy was performed on the first visit noting optic nerve asymmetry and CD’s of 0.3 and 0.4. Seven years later, the optic nerves were 0.6 OD and 0.9 OS. The glaucoma consult confirmed glaucoma OU but advanced glaucoma OS. Was there something that could have been identified sooner to determine why this patient may have had escalating pressures?
The final diagnosis was pigmentary glaucoma, and so many times these uncontrollable glaucoma cases are in the class of secondary glaucomas. In this case the key was to observe the signs of pigment dispersion syndrome (PDS) before it became pigmentary glaucoma. Signs of PDS include a vertical line of pigment on the central corneal endothelium known as Krukenberg spindles, iris transillunination and pigment in the trabecular meshwork (TM) on gonioscopy examination. There is also a fourth sign known as Scheie line where pigment deposits along the peripheral posterior lens capsule – this would only be observed through pupil dilation. These findings tend to be bilateral and most commonly affect younger to middle aged men.
The theory of why this type of glaucoma can become extreme in terms of elevated IOP and non-response or loss of response to medications in patients who have had PDS for a long time, is likely due to scarring of the TM. This leads to a collapse of the intra- trabecular spaces and blockage of aqueous outflow.
It is important for clinicians to look for the signs of PDS, to understand the risks of developing pigmentary glaucoma and to monitor IOP and optic nerve findings on a regular basis.
Understanding the secondary glaucomas is very important since these can progress much faster than primary open angle glaucoma. Look for key signs while these conditions are syndromes and monitor them to prevent progression to glaucoma.
REF: 1. Miglior S, Bertuzzi F, Exfoliative glaucoma: new evidence in the pathogenesis and treatment. Prog Brain Res. 2015;221:233-41.
2. J. B. RoedlS. BleichU. Reulbach et al. Vitamin deficiency and hyperhomocysteinemia in pseudoexfoliation glaucoma Journal of Neural Transmission. May 2007, Volume 114, Issue 5, pp 571–575
3. Samarai V, Samarei R, Haghighi N, et al. Sensory-neural hearing loss in pseudoexfoliation syndrome. Int J Ophthalmol. 2012;5(3):393-6.