FAQs / I Am Very Nearsighted. I’ve Been Told That I Could Be at Higher Risk for Complications after Glaucoma Surgery. Why Is This?

QUESTION:

I am very nearsighted. I’ve been told that I could be at higher risk for complications after glaucoma surgery. Why is this?

ANSWER:

High myopes (those who are extremely near-sighted) are at greater risk for developing vision-threatening hypotony maculopathy after trabeculectomy or glaucoma drainage device surgery. This is one of the reasons I prefer canaloplasty in my area which has a disproportionate number of myopes due to the racial mix of my community.

Extreme myopes may also suffer from a condition termed “scleral rigidity” which can result in widely fluctuating IOPs and frustration or failure with multiple glaucoma surgeries. Think of the highly myopic eye as a thin-walled ball. Pumping up a thin-walled plastic (not rubber) ball will result in a squishy ball until just before it is filled with air. Once filled it is suddenly firm. The next half pump of air makes it rock solid.

Such is the case with extremely high myopes. When there is less than a certain amount of aqueous fluid in the eye the IOP is too low (hypotony). A few micoliters more and the IOP shoots up past 30mmHg. There’s just very little “wiggle-room” in terms of how much fluid a myopic eye can hold and maintain an ideal pressure. Truly, myopic eyes are the high-maintenance Goldilocks of eyes.

Oh, did I mention that the sclera (eye wall) tends to be much thinner in myopic eyes? This makes creation of a partial thickness scleral flap (required in both trabeculectomy and canaloplasty) quite challenging. With canaloplasty the surgeon actually has to create two partial thickness flaps! No wonder so few surgeons are volunteering to take on this challenge.

Bottom line is that the highly nearsighted who also have glaucoma should expect to face challenges in both the diagnosis and treatment of their glaucoma.

Warm regards,
David Richardson, MD
Patient-Focused Ophthalmologist

San Marino Eye
2020 Huntington Drive
San Marino, CA 91108
626.289.7856

Patient-Focused Websites:
New-Glaucoma-Treatments.com
About-Eyes.com

Date: Nov 23, 2014

Posted in: Canaloplasty and Other Conditions, Glaucoma