Clinical Evaluation of Patients with Ocular Vascular Occlusive Disorders




(1)
Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, USA

 



In my Ocular Vascular Clinic at the University of Iowa Hospitals and Clinics, when patients with ocular vascular occlusive disorders are seen for the first time with a history of visual loss (usually sudden), I do the evaluations myself. The following is a detailed account of my method of evaluating these patients.


Initial Evaluation of All Patients with Visual Loss


The data of my various clinical studies on ocular vascular occlusive disorders (summarized in this book) are based on the findings from these evaluations at the initial and follow-up visits. I am well aware that everyone has his/her own way of examining these patients, but this is how I have evaluated all my patients in the various studies over the years.

The entire workup of all new patients is done by me personally.


Detailed History


The first, critical step in the diagnosis and management of these or any patients is to have a detailed history; this is the “bedrock.” What the patient has to tell will provide critical information, which may lead eventually to the correct diagnosis. Therefore, I spend a lot of my time to obtain a detailed history from the patient when he/she is first seen in my clinic. This is very time-consuming but is an investment which pays dividends in arriving at the correct diagnosis. I always tell my residents and fellows: “We do not want to practice veterinary medicine!”


History of Present Illness


Since the University of Iowa Hospitals and Clinics is a tertiary referral center, the majority of patients are referral patients. When I first ask the patient to tell me what happened, it is not uncommon for them to start by telling me the diagnosis of the previous ophthalmologist. I then tell them that I am interested in what exactly his/her primary problem is and ask the patient to tell me in his/her own words, in detail, all about what happened, right from the beginning. I let the patient describe the process at length and listen to what he/she has to say without interrupting, although sometimes guiding them toward the information which may be relevant. After that, I question the patient to obtain various specific pieces of information which the patient may not have given, without hinting in any way what the right answer is. I particularly ask the patient the following questions, if he/she has not already given the answer:

(i)

Mode of onset of visual loss, i.e., was it sudden or gradual?

 

(ii)

How did the patient first discover the visual loss? That is, suddenly noticing visual loss or happening to cover one eye and discover the visual loss accidentally? Or did he/she become aware of the visual loss for some other reason? How long ago was this discovered?

 

(iii)

The time of the day when he/she first noticed the visual loss.

 

(iv)

Was the visual loss accompanied by other ophthalmic or systemic symptoms?

 

(v)

What other eye problems had he/she already had before the onset of this visual loss? This is important; for example, a patient may have had glaucoma or ocular hypertension, which can play a role in the development of ocular vascular occlusive disorders.

 

(vi)

I ask them to describe the location of their visual loss.

 

(vii)

Since the onset, has the visual loss been stable or progressively worsening or improving?

 

(viii)

Did he/she experience amaurosis fugax before the visual loss? This is important because amaurosis fugax is seen in several ocular vascular occlusive disorders [1] (see Chap. 28) and may provide important information about the cause.

 

(ix)

Was the visual loss associated with or preceded by episodes of any type of color vision? This is because ischemic lesions are sometimes associated with purple or similar shades of color or hue.

 

(x)

I ask the patient if he/she has any other relevant information to offer about the present illness. This makes them think twice and sometimes recall vital information at this point.

 


History of Previous Eye Diseases


Detailed information about these is essential because they may well be relevant.


Medical History


I always tell my residents and fellows that it is a whole patient, with two eyes, who is coming to consult us. It is not one eye, an optic nerve, retina, cornea, lens, or other part of the eye which walks into the clinic to consult an ophthalmologist. Lack of awareness of this very basic fact can result in missing the correct diagnosis. The eye is a part of the entire body and we know that many systemic diseases can play important roles in the development of many ophthalmic diseases. This is particularly so in the case of ocular vascular occlusive disorders. Therefore, I quiz the patient repeatedly and thoroughly, to obtain a detailed medical history. Since giant cell arteritis is important in causing some of the ocular vascular occlusive disorders and that is an ophthalmic emergency, in middle aged and elderly patients, a full questioning about the various symptoms and signs of that disease is critical for immediate diagnosis and start of therapy, to prevent severe and irreversible visual loss. We know that ocular vascular occlusive disorders are often multifactorial in nature, with many systemic risk factors playing roles. My large prospective studies, based on patients with non-arteritic anterior ischemic optic neuropathy [2], retinal artery [3], and vein occlusions [4], showed associations with many systemic diseases. Therefore, I question the patient about all those, including diabetes mellitus, hyperlipidemia, arterial hypertension, malignant arterial hypertension, ischemic heart and other cardiovascular diseases, cardiac and valvular disease, carotid artery disease, cerebrovascular disease, neurological disease, endocrinal disorders, hematologic disorders, gastrointestinal ulcers, hemodialysis, collagen vascular diseases (including systemic lupus erythematosus, polyarteritis nodosa, and Wegener’s granulomatosis), migraine and other vasospastic disorders, herpes zoster, sleep apnea, and renal, rheumatologic, infectious, and other diseases. Any history of syphilis and HIV infection should also be obtained. Some systemic surgical procedures can produce some of the ocular vascular occlusive disorders; therefore, it is essential to find out about that. We also know that distant repeated hemorrhages can result in the development of non-arteritic anterior ischemic optic neuropathy [5]. Currently, erectile dysfunction drugs are widely used, and those have been found to cause non-arteritic anterior ischemic optic neuropathy [6]. Finally, I ask every patient about other major medical events at any time in their life. Sometimes, when asked about systemic diseases, the patient responds at first that “they never have had anything wrong with them.” In such a case, my next question invariably is: have you ever seen a doctor, and why? That sometimes reveals new information. Thus, to get a full picture about systemic diseases is a time-consuming job but can provide important clues about ocular vascular occlusive disorders.


Family History


It is important to enquire about medical and ophthalmic problems in the family. When a patient gives a history that most of their relatives have died of myocardial infarction or stroke at an early age, that is suggestive of familial hyperlipidemia. We know that hyperlipidemia is a risk factor for development of ocular vascular occlusive disorders. I always ask if there is any history of blindness, poor vision, or glaucoma in the family; that information may be relevant in some cases.


Social History


I always ask each and every patient about smoking – if he/she has ever smoked, and if so when did he/she start, how much did he/she smoke, and if he/she is still smoking. I also ask them about drug abuse and the use of alcohol (how much and how often).


Medications


Information about the various drugs the patient is taking and their dosage and frequency is essential. This is because those may play a role in the development of ocular vascular occlusive disorders or may worsen them. Currently a large number of very potent drugs have emerged to treat arterial hypertension (a common disease in the middle-aged and elderly), and those are being widely prescribed. My studies have shown that nocturnal arterial hypotension plays an important role in the development of some ocular vascular occlusive disorders, as discussed in various disorders [7]. My 24-h ambulatory blood pressure recording study in more than 700 patients has shown that when an arterial hypotensive drug(s) is taken in the evening or at bedtime, that often results in abnormal nocturnal arterial hypotension [8]. If a patient is taking these drugs in the evening, I invariably ask him/her whether that timing is because of the advice of his/her doctor or not. Not infrequently the patients decide to take their medication in the evening or at bedtime on their own, for no apparent reason. My studies have also shown that overmedication with arterial hypotensive drugs to treat arterial hypertension by physicians is not uncommon (some patients being treated aggressively for simple white-coat hypertension [7]) and that can have the same effect. I have seen the development of non-arteritic anterior ischemic optic neuropathy when patients were started on Hytrin (terazosin hydrochloride – an alpha-1-selective adrenoceptor blocking agent) or allied drugs (all arterial hypotensive) for benign prostatic hypertrophy, taken at bedtime. Therefore, as a rule, it is most important to ask that question in that age group. If a patient is on any arterial hypotensive drug, it is important to ask how many of those drugs he/she is taking and when. In my experience of referral cases, I find that when evaluating ocular vascular occlusive disorders, this important question about arterial hypotensive drugs has rarely been asked by the ophthalmologist or neuro-ophthalmologist. As discussed under various ocular vascular occlusive disorders in this book, nocturnal arterial hypotension can play a role in the development of non-arteritic anterior ischemic optic neuropathy, central retinal artery occlusion, and some of other ocular vascular occlusive disorders, including ocular ischemic syndrome, conversion of nonischemic central retinal vein occlusion to ischemic central retinal vein occlusion, or their worsening. Similarly, as discussed below, the use of aspirin or anticoagulants worsens the visual outcome in retinal vein occlusion [9].


Detailed Ophthalmic Evaluation


It is crucial to evaluate the eye from A to Z, irrespective of the suspected site of visual loss. It is not a good practice to focus simply on the eye the patient is complaining about or only the part of the eye which one suspects is responsible for the visual problem. I have found that a very common problem; for example, neuro-ophthalmologists are concerned only with what is relevant to them in the eye, retina specialists with only the retina, cornea persons with the cornea, and so on. For example, there was a cornea specialist who performed a corneal graft in a patient and put her on corticosteroid eye drops on a long-term basis and only checked the corneal graft on regular follow-up visits; he never measured the intraocular pressure. When I saw the patient, she had advanced glaucoma damage with massive visual field loss and poor visual acuity and intraocular pressure in the 40s. That means her visual acuity and intraocular pressures were never evaluated by the cornea specialist, whose sole interest was the state of the graft. I also saw another patient who was followed by an ophthalmic plastic surgeon who did not examine the fundus, and the patient was found to have an advanced malignant melanoma with macular sparing. Over the years I have seen many similar examples. Such a disaster can easily be avoided if an eye is routinely examined fully whenever a patient is being examined, initially and during follow-up.

Moreover, ophthalmologists sometimes evaluate only the eye about which the patient is complaining and forget that the patient has two eyes and that the second eye may also have something going on, which may provide crucial information about the cause. For example, I discovered that asymptomatic optic disc edema precedes the visual loss in non-arteritic anterior ischemic optic neuropathy [10], and that incipient non-arteritic anterior ischemic optic neuropathy [11], a definite clinical entity, can only be detected by examining the fellow eye regularly at each visit, irrespective of whether the patient had any complaint related to the fellow eye or not. In a few giant cell arteritic cases, I found early signs of arteritic anterior ischemic optic neuropathy in an asymptomatic eye. The fact that an eye is asymptomatic does not automatically rule out the possibility of pathology. Similarly, patients with central retinal vein occlusion almost always have normal intraocular pressure in the involved eye, but they may have a very high intraocular pressure or glaucoma in the fellow eye (unknown to the patient), which was responsible for the development of central retinal vein occlusion in the first place [12, 13]. Missing that information puts the fellow eye at risk of developing glaucomatous visual loss or even central retinal vein occlusion. These are just a few examples of the reason why a thorough evaluation of both eyes is crucial at each and every visit.


Testing Visual Function in Patients with Ocular Vascular Occlusive Disorders


I use the following four tests.


Snellen Visual Acuity Testing


This is usually delegated to technicians, but I have found that testing of visual acuity is an art and a science. It is perhaps the most important test for all ophthalmic patients, for two reasons: (a) A patient’s main interest obviously is to find out how much he/she can see and whether it is getting better or worse – that is primarily why they have come to consult an ophthalmologist. (b) Similarly, ophthalmologists are primarily interested to find out whether a particular treatment has had a beneficial effect on the visual acuity or not. For both patients and ophthalmologists, visual acuity is of prime importance. Yet it is usually assessed by persons who do not have full knowledge of the diseases and the factors which influence the visual acuity testing. I have had patients referred to me (even from other clinics in my own department) with only “hand motion visual acuity” recorded by a technician, but less than half an hour later, I can often get as good as 20/200 or even better in them. This is because patients with a large central scotoma or with a visual field defect involving central fixation area have a natural tendency to fixate at the center of the visual acuity chart and say, truthfully, that they cannot see anything. The technician then puts his/her fingers in the central field to find out if he/she can count fingers, but since the fingers are lying in the central scotoma, the patient cannot see them. The next step is that the technician waves the hand, which goes into the seeing area and a visual acuity of hand motion is recorded erroneously.

Throughout my ophthalmic career, I have tested visual acuity in all my patients myself. For the reasons discussed above, it is well worth the time spent to get valid information. As described above, there is a natural tendency for the patient to fixate at the center of the chart, but when they have a central scotoma or when a visual field defect involves the central fixation area, they are not able to read the chart. Therefore, right at the start of testing, I tell them that by fixating at the center of the chart they may not be able to see properly or anything at all, but that they should look around to find out a spot where they can see best, that is, I encourage them to use eccentric fixation. Patients often do not know what “eccentric fixation” means, so I try to give them a simple example. I tell them, for example, “If you go to a party and want to know what someone is wearing, but you do not want that person to know that you are staring at him/her, what do you do?” He/she immediately says that you look straight ahead but look at them “out of the corner of your eye.” That gives them the idea of what eccentric fixation is. I give a patient all the time he/she needs to discover by various head or eye movements where he/she can see best and how much, making sure that the other eye is completely covered. Often patients are surprised how much better they can see with eccentric fixation. This also acts as useful education for the patient. I have found that some patients are delighted to find that they can see better and are able to watch television with eccentric fixation. On follow-up visits the same procedure is repeated to get reliable visual acuity data. Of course, valid visual acuity is the best corrected visual acuity.

This limitation of simple visual acuity testing has important implications in the visual acuity results reported by various studies dealing with various modes of treatment. When a patient has a central scotoma or a visual field defect which involves the central fixation area, he/she tests poorly at initial testing, with poor visual acuity for the reasons mentioned above. In due course many patients may learn to fixate eccentrically and see much better, and that apparent improvement may be attributed to the beneficial effect of a treatment, when in fact the treatment has not actually helped. This is not rare among published claims of beneficial effects for some treatments.

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Oct 28, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Clinical Evaluation of Patients with Ocular Vascular Occlusive Disorders
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