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Novel Patient Education Tool for Estimating Intraocular Pressure

Novel Patient Education Tool for Estimating Intraocular Pressure

Kimberly Pham1, Don Kim1, Agastya Gupta2, Gloria Wu3

University of California, Berkeley1; Stanford University 2; University of California, San Francisco3


Patient self-examinations plays a role in the diagnosis and prevention of disease, e.g. breast, skin, and testicular cancer. Currently, patient self-examination techniques serve to educate the public and are a cost effective means for early detection of disease states. To date, there is no standardized self-examination of common eye problems, such as glaucoma, a leading cause of blindness in the United States (2.7 million) and the world (61 million).

Considering the role of breast self-examinations in the early detection of breast cancer, we apply this same concept to self-examination for glaucoma and increased intraocular pressure. Intraocular pressure measurement devices currently exist, but are typically too costly, ineffective, or too complicated to be implemented at home by the average patient. Thus, we want to develop a simple, economical testing device for self-estimation of intraocular pressure.

Self-exams for elevated IOP in normal patients, open angle and closed angle patients, would increase public awareness of glaucoma. Currently, open angle glaucoma patients do not take their medications regularly and non-compliance with glaucoma eye drops is approximately 23-60% in the United States. A self-exam may make glaucoma patients more aware of the risk-benefits of treatment and possibly improve their motivation of using their topical medications.

Lastly, acute angle closure glaucoma can occur in the setting of nursing homes, geriatric rehabilitation facilities where patients may be given drugs, which can precipitate glaucoma, such as pilocarpine, atropine,and tricyclic antidepressants. Nurses, LPNs, and Nursing assistants can be taught “self-examination” techniques for glaucoma, thus making them aware of the importance of intraocular pressure and glaucoma for their elderly patients. Oftentimes, in the nursing home, no eye care specialist is consulted for narrow or closed angle glaucoma until it is too late and the patient has lost all of his vision.

Figure 1 The Problem
  1. Limited public awareness or heightened concern about the seriousness of glaucoma, a leading cause of blindness
  2. Non-compliance with using glaucoma medications
  3. No self-exam for Glaucoma

The Glaucoma ball* is a set of a 40A, 20A and 10A durometer rubber balls, each 2 cm in diameter, which represents 40 mmHg, 20 mmHg, and 10 mmHg, respectively. Each ball was measured with slit lamp applanation tonometer to corroborate eye pressure.Controls and patients had IOP checked by an ophthalmologist (GW) using slit lamp applanation tonometry.

After initial measured IOP (Pre-IOP), patients were instructed to self-palpate their globe through closed eyelids, palpate the 3 Glaucoma balls, and then estimated their IOP (Est-IOP), choosing a number between 10mm, 20 mm, and 40 mmHg. This number was recorded. The test taker also chose one of the 3 balls that best approximated his estimated intraocular pressure (Est-IOP),before authors revealed his measured IOP (Pre-IOP).  Final IOP (Post-IOP) was measured by an ophthalmologist (GW) using applanation tonometry.

Informed consent was obtained.

Inclusion criteria: Normal volunteers, ophthalmology patients; Exclusion criteria: Patients with peripheral neuropathy, severe vision, inability to understand instructions in English

Statistical analysis: Chi-square test *patent pending

Figure 2 Glaucoma Ball (10mmHg, 20 mmHg, and 40 mmHg, respectively)



Table 1 Measured and Est-IOP (n=42)






15.3 + 2.6

17.2 + 4.5

14.3 + 2.5

Δ from Est- IOP (Avg+sd)

3.8 + 3.5

3.8 + 3.5

T-test vs Est-IOP




  1. The vast majority of test takers were able to choose between 40 mmHg glaucoma ball and those with normal eye pressure (10mm and 20 mmHg).
  2. While two-thirds of the Test Takers were able to estimate their IOP within 3 mmHg, we need further studies with more patients and repeat instruction to evaluate test reliability and accuracy.
  3. Just as the Breast Self-exam is not 100% accurate, we hope that the Glaucoma Ball Self-exam is a starting point of patient education and increased health awareness of glaucoma.
  1. Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmology 2006; 90:262–26.
  2. Richardson C, Brunton L, Waterman H. A study to assess the feasibility of undertaking a randomized controlled trial of adherence with eye drops in glaucoma patients. Patient Prefer Adherence 2013; 7:1025-1039.
  3. Shrivastava, SR, Prateek SS, Jegadeesh R. Self Breast Examination: A Tool for Early Diagnosis of Breast Cancer. Am J Public Health 2013; 135-139.
  4. Robinson JK, Fisher SG, Turrisi RJ. Predictors of skin self-examination performance. Cancer 2002; 95(1): 135-146.
  5. “Glaucoma. Open Angle”. National Eye Institute. http://www.nei.nih.gov/eyedata/glaucoma.asp. Accessed April 14, 2014.
  6. “Glaucoma”. Google trends. http://www.google.com/trends/explore#q=glaucoma. Accessed April 28, 2014.

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