The patient complains of headache and blurred vision during exercise. What may be responsible for this?

Answer
During exercise there may be an increased in pigment liberation and 
couple with the mydriasis from sympathetic activation, the intraocular
pressure may increase sharply leading to headache and blurred vision.
 

What is the advantages and disadvantages of using parasympathomimetic in treating this patient's pressure? What is the treatment of choice?

Answer
Parasympathomimetics such as pilocarpine can in theory increase
the relative pupillary block and relieve iridozonular contact and 
diminish pigment liberation. Ultrasound biomicroscopy has been 
used to show the relief of iridozonular contact following miotic therapy. 
However, in young individuals pilocarpine are rarely tolerated because 
of the associated spasm of accommodation and blurring of vision. In 
addition, miotic is associated with an increase incidence of retinal 
detachment especially in this group of patients (due to the higher
incidence of lattice degeneration).
Beta blocker is the treatment of choice. 
 

If this patient has asthma, is the use of latanoprost contraindicated in this patient?

Answer
No. Although latanoprost increases iris pigmentation it does so 
by increasing melanin production by the iris melanocytes. It does 
not affect the iris pigment epithelium where the pigment originates.

 

How may laser be used in this patient if the intraocular pressure is not controlled with medication?

Answer
Laser may be used in two ways:
a. Laser trabeculoplasty. Argon laser trabeculoplasty can be used 
to manage uncontrolled pigmentary glaucoma. Although the initial
result is often good, a larger proportion of patients can lose control 
of IOP when compared to primary open angle glaucoma patients, 
and the loss of control can occur in less time (9 months vs 2-3 years). 
In contrast to other forms of open angle glaucoma, younger patients
appear to respond better to trabeculoplasty than do older individuals.
(Hagadus J, Ritch R, Pollack I, et al: Argon laser trabeculoplasty in
pigmentary glaucoma. Invest Ophthalmol Vis Sci 25(Suppl):94, 1984.)
b. Laser iridectomy. Laser iridectomy eliminates the iris concavity by 
equalizing pressures between the anterior and posterior chambers.
This causes the iris to become flat, thereby decreasing iridozonular 
contact. Anecdotal evidence suggests that this can prevent continued 
pigment liberation, result in a reversal of trabecular pigmentation, and
subsequently, lowering of IOP. However, long term effectiveness of this
treatment remain unknown. 
(Campbell DG, Schertzer RM: Pigmentary glaucoma. In Ritch R, 
Shields MB, Krupin T (eds): The Glaucomas. St. Louis, CV Mosby,
1996.)
 

What is the natural history of this condition?

Answer
The natural history may be divided into the active and regression phase:
In the active phase, the onset is probably in the mid-20s in which
liberation of pigment is the most active. The development of pigment
dispersion syndrome in later is uncommon because of gradual lens 
enlargement.
The regression phase occurs when the severity of pigment dispersion
syndrome and pigment glaucoma decreases usually in the middle age
when pigment liberation reduces or ceases in the majority of patients.
The pigment in the trabecular meshwork decreases because the pigment 
could pass out of the meshwork with time. Also the transillumination
defect may disappear possibly caused by migration of pigment epithelial 
cells next to the defect. The intraocular pressure may return to normal.
If glaucoma was detected at this phase, it may be misdiagnosed as 
primary open-angle glaucoma or low-tension glaucoma.