The Making of a Good Diagnostician

Patients with vision loss should undergo all pertinent ancillary diagnostic tests to ensure complete assessment of the condition at hand.

By Mohammad R. Rafieetary, OD, and Melvin A. Friedman, OD

With the speed, ease of testing, and reliability of objective findings now available with imaging technologies such as optical coherence tomography (OCT), clinicians may overlook the utility of some older diagnostic tools when the reason for a patient’s vision loss is not entirely explained by the physical examination. In the past decade, the use of ocular imaging devices for the management of patients with a diagnosis of primary open-angle glaucoma has significantly increased by both optometrists and ophthalmologists.1

At times, clinicians fail to listen to patients or come to conclusions too quickly, taking them off the path of making the right clinical decisions. In the book How Doctors Think, Jerome Groopman, MD, describes how physicians interrupt patients within 18 seconds in their initial history taking, by which time they have come to a diagnostic conclusion.2 The author also notes how difficult it is for a clinician to change his or her mind about an initial impression. In this article, we present a case in which these mistakes were made.

CASE PRESENTATION

A 44-year-old black man first presented to one of the authors (MAF) and was subsequently referred for further evaluation to the other author (MRR) with visual complaints of blurred vision in the right field of the right eye for 2 months and fading of letters in and out while reading. The patient had been examined a number of times previously by an optometrist and an ophthalmologist for the same complaint, and these clinicians attributed his complaint to dry eyes. Despite treatment for dry eye disease, the patient had not experienced relief of his symptoms, and therefore he pursued another professional opinion.

The patient’s medical history was remarkable for systemic hypertension, and he admitted to poor compliance with his treatment. He had worn soft contact lenses for a number of years. Examination showed best-corrected visual acuity of 20/40 OD and 20/20 OS. The pupils were round and reactive to light with no afferent pupillary defect. Intraocular pressure was 18 mm Hg OD and 15 mm Hg OS. Primary gaze and extraocular motilities were normal in each eye. The lids and lashes were clear. The cornea showed mild punctate staining and a few round anterior stromal opacities indicative of prior infiltrative processes. The anterior chamber, iris, and crystalline lens were normal OU.

Fundus examination revealed a cup-to disc ratio of 0.6 with temporal slope OD and 0.5 with flat temporal rim OS. Maculas were normal OU. There was mild arteriosclerosis OU. Peripheral retinas were normal.

Figure 1. Nerve fiber layer analysis shows generalized thinning OU, with significant atrophy temporally OD and nasally OS.

Figure 2. Optic nerve head and cup-to-disc ratios were asymmetric.

Spectral-domain OCT (Spectralis; Heidelberg Engineering) imaging revealed abnormalities in retinal nerve fiber layer thickness (Figure 1). The optic nerve profile was essentially normal with horizontal manually measured Bruch membrane opening (BMO) of 1,235 µm OD and 1,211 µm OS, demonstrating mildly asymmetric findings (Figure 2). Macular scans were normal.

Visual field screening (Humphrey Visual Field Analyzer, Carl Zeiss Meditec) by MAF had demonstrated abnormal findings greater OD than OS. A threshold examination was scheduled.

In the meantime, the patient was referred to an internal medicine specialist for reassessment and management of his systemic hypertension. Upon return a few days later, a 30-2 threshold visual field test (Humphrey Visual Field Analyzer) revealed a bitemporal field defect (Figure 3).

Neuroimaging was ordered, and the images showed a 3-cm pituitary macroadenoma filling the sella and superasellar cistern and compressing the optic chiasm.

DISCUSSION

Pituitary tumors are common and generally benign; many go undetected due to lack of symptoms.3-5 Diagnosis may be made based on hormonal hypersecretion, hypopituitarism, and neurologic dysfunction, including visual symptoms. Significant numbers of patients with pituitary adenomas have visual field defects.6 The extent of the visual field finding is usually related to the size of the mass (Figure 4).7 The most common type of visual field finding is a bitemporal defect; however, this can also be a finding in other conditions such as tilted disc syndrome.8

Figure 3. Heteronymous bitemporal visual field defects were present.

Figure 4. Different size tumors result in varying degrees of visual field defects.

In addition to a thorough physical eye examination, patients complaining of vision loss should have all pertinent ancillary diagnostic tests such as a visual field examination to ensure complete assessment of the condition at hand. In the era of enhanced subjective testing, it is too easy to rely on tests such as OCT that may not allow the clinician to complete the diagnostic circle. n

Mohammad R. Rafieetary, OD, is an associate at the Charles Retina Institute in Memphis, Tennessee. He acknowledged no financial interest in the products or companies mentioned herein. Dr. Rafieetary may be reached at mrafieetary@charlesretina.com.

Melvin A. Friedman, OD, is in private practice at For Your Eyes Only in Memphis, Tennessee. He acknowledged no financial interest in the products or companies mentioned herein. Dr. Friedman may be reached at dfried007@aol.com.

1. Stein JD, Talwar N, Laverne AM, et al. Trends in use of ancillary glaucoma tests for patients with open-angle glaucoma from 2001 to 2009. Ophthalmology. 2012;19(4):748-758.

2. Groopman JE. How Doctors Think. New York, NY: Houghton Mifflin; 2007.

3. McDowell BD, Wallace RB, Carnahan RM, et al. Demographic differences in incidence for pituitary adenoma. Pituitary. 2011;14(1):23-30.

4. Buurman H, Saeger W. Subclinical adenomas in postmortem pituitaries: classification and correlations to clinical data. Eur J Endocrinol. 2006;154:753-758.

5. Costello RT. Subclinical adenoma of the pituitary gland. Am J Pathol. 1936;12:205-216.

6. Thomas R, Shenoy K, Seshadri MS, et al. Visual field defects in non-functioning pituitary adenomas. Indian J Ophthalmol. 2002;50(2):127-130.

7. Jung PL, Chung YS. The volume of tumor mass and visual field defect in patients with pituitary macroadenoma. Korean J Ophthal. 2011; 25(1):37-41.

8. Sowka JW, Luong VV. Bitemporal visual field defects mimicking chiasmal compression in eyes with tilted disc syndrome. Optometry. 2009;80(5):232-242.