During an eye examination, a test such as cover testing or the Hirschberg test is used in the diagnosis and measurement of strabismus and its impact on vision. Retinal birefringence scanning can be used for screening of young children for eye misaligments.

Several classifications are made when diagnosing strabismus.

The cross-cover test, or alternating cover test is usually employed to detect heterophoria. One eye is covered, and then the cover is moved immediately over to the other eye. With heterophoria, when the cover is moved to the other eye, the eye that has just been uncovered can be seen to move from a deviated point. The difference between heterotropia and heterophoria can be easily understood as follows. With heterotropia, a correcting movement of the eye can be detected already by the simple cover test; with heterophoria, such correcting movement only takes place in the cross-cover test. People with heterophoria are able to create and maintain binocular fusion through vergence, and the cross-cover test purposely breaks this fusion, making the latent misaligment visible.

Whereas the cross-cover test allows a qualitative assessment to be done, a quantitative assessment of latent eye position disorders can be done using the Lancaster red-green test.

The prognosis for each patient with esotropia will depend upon the origin and classification of their condition. However, in general, management will take the following course:

1. Identify and treat any underlying systemic condition.

2. Prescribe any glasses required and allow the patient time to 'settle into' them.

3. Use occlusion to treat any amblyopia present and encourage alternation.

4. Where appropriate, orthoptic exercises can be used to attempt to restore binocularity.

5. Where appropriate, prismatic correction can be used, either temporarily or permanently, to relieve symptoms of double vision.

6. In specific cases, and primarily in adult patients, botulinum toxin can be used either as a permanent therapeutic approach, or as a temporary measure to prevent contracture of muscles prior to surgery

7. Where necessary, extra-ocular muscle surgery can be undertaken to improve cosmesis and, on occasion, restore binocularity.

Strabismus can be manifest ("-tropia") or latent ("-phoria"). A manifest deviation, or heterotropia (which may be "eso-", "exo-", "hyper-", "hypo-", "cyclotropia" or a combination of these), is present while the patient views a target binocularly, with no occlusion of either eye. The patient is unable to align the gaze of each eye to achieve fusion. A latent deviation, or heterophoria ("eso-", "exo-", "hyper-", "hypo-", "cyclophoria" or a combination of these), is only present after binocular vision has been interrupted, typically by covering one eye. This type of patient can typically maintain fusion despite the misalignment that occurs when the positioning system is relaxed. Intermittent strabismus is a combination of both of these types, where the patient can achieve fusion, but occasionally or frequently falters to the point of a manifest deviation.

In order to understand how heterophoria occurs, we must understand of how the eye can maintain proper fixation with non aligned visual axis. Heterophoria is actually the misalignment of the visual axis of both eyes. In other words, one or both eyes are not properly fixated to an object of interest. However, we must know that the eyes have a fusional vergence system which corrects this misalignment.

"Congenital esotropia," or "infantile esotropia," is a specific sub-type of primary concomitant esotropia. It is a constant esotropia of large and consistent size with onset between birth and six months of age. It is not associated with hyperopia, so the exertion of accommodative effort will not significantly affect the angle of deviation. It is, however, associated with other ocular dysfunctions including oblique muscle over-actions, Dissociated Vertical Deviation (DVD,) Manifest Latent Nystagmus, and defective abduction, which develops as a consequence of the tendency of those with infantile esotropia to 'cross fixate.' Cross fixation involves the use of the right eye to look to the left and the left eye to look to the right; a visual pattern that will be 'natural' for the person with the large angle esotropia whose eye is already deviated towards the opposing side.

The origin of the condition is unknown, and its early onset means that the affected individual's potential for developing binocular vision is limited. The appropriate treatment approach remains a matter of some debate. Some ophthalmologists favour an early surgical approach as offering the best prospect of binocularity whilst others remain unconvinced that the prospects of achieving this result are good enough to justify the increased complexity and risk associated with operating on those under the age of one year.

A comprehensive eye examination including an ocular motility (i.e., eye movement) evaluation and an evaluation of the internal ocular structures will allow an eye doctor to accurately diagnose the exotropia. Although glasses and/or patching therapy, exercises, or prisms may reduce or help control the outward-turning eye in some children, surgery is often required.

There is a common form of exotropia known as "convergence insufficiency" that responds well to orthoptic vision therapy including exercises. This disorder is characterized by an inability of the eyes to work together when used for near viewing, such as reading. Instead of the eyes focusing together on the near object, one deviates outward.

"Consecutive exotropia" is an exotropia that arises after an initial esotropia. Most often it results from surgical overcorrection of the initial esotropia. It can be addressed with further surgery or with vision therapy; vision therapy has shown promising results if the consecutive exotropia is intermittent, alternating and of small magnitude. (Consecutive exotropia may however also spontaneously develop from esotropia, without surgery or botulinum toxin treatment.)

Because of the risks of surgery, and because about 35% of people require at least one more surgery, many people try vision therapy first. This consists of visual exercises. Although vision therapy is generally not covered by American health insurance companies, many large insurers such as Aetna have recently begun offering full or partial coverage in response to recent studies.

Strabismus surgery is sometimes recommended if the exotropia is present for more than half of each day or if the frequency is increasing over time. It is also indicated if a child has significant exotropia when reading or viewing near objects or if there is evidence that the eyes are losing their ability to work as a single unit (binocular vision). If none of these criteria are met, surgery may be postponed pending simple observation with or without some form of eyeglass and/or patching therapy. In very mild cases, there is a chance that the exotropia will diminish with time. The long-term success of surgical treatment for conditions such as intermittent exotropia is not well proven, and surgery can often result in a worsening of symptoms due to overcorrection. Evidence from the available literature suggests that unilateral surgery was more effective than bilateral surgery for individuals affected with intermittent exotropia.

The surgical procedure for the correction of exotropia involves making a small incision in the tissue covering the eye in order to reach the eye muscles. The appropriate muscles are then repositioned in order to allow the eye to move properly. The procedure is usually done under general anesthesia. Recovery time is rapid, and most people are able to resume normal activities within a few days. Following surgery, corrective eyeglasses may be needed and, in many cases, further surgery is required later to keep the eyes straight.

When a child requires surgery, the procedure is usually performed before the child attains school age. This is easier for the child and gives the eyes a better chance to work together. As with all surgery, there are some risks. However, strabismus surgery is usually a safe and effective treatment.

Exotropia is a form of strabismus where the eyes are deviated outward. It is the opposite of esotropia and usually involves more severe axis deviation than exophoria. People with exotropia often experience crossed diplopia. Intermittent exotropia is a fairly common condition. "Sensory exotropia" occurs in the presence of poor vision. Infantile exotropia (sometimes called "congenital exotropia") is seen during the first year of life, and is less common than "essential exotropia" which usually becomes apparent several years later.

The brain's ability to see three-dimensional objects depends on proper alignment of the eyes. When both eyes are properly aligned and aimed at the same target, the visual portion of the brain fuses the forms into a single image. When one eye turns inward, outward, upward, or downward, two different pictures are sent to the brain. This causes loss of depth perception and binocular vision. There have also been some reports of people that can "control" their afflicted eye. The term is from Greek "exo" meaning "outward" and "trope" meaning "a turning".

Pseudomyopia refers to an intermittent and temporary shift in refractive error of the eye towards myopia, in which the focusing of light in front of the retina is due to a transient spasm of the ciliary muscle causing an increase in the refractive power of the eye. It may be either organic, through stimulation of the parasympathetic nervous system, or functional in origin, through eye strain or fatigue of ocular systems. It is common in young adults who have active accommodation, and classically occurs after a change in visual requirements, such as students preparing for an exam, or a change in occupation.

The major symptom is intermittent blurring of distance vision particularly noticeable after prolonged periods of near work, and symptoms of asthenopia. The vision may clear temporarily using concave (minus) lenses. The diagnosis is done by cycloplegic refraction using a strong cycloplegic like atropine or homatropine eye drops. Accommodative amplitude and facility may be reduced as a result of the ciliary muscle spasm.

Treatment is dependent on the underlying aetiology. Organic causes may include systemic or ocular medications, brain stem injury, or active ocular inflammation such as uveitis. Functional pseudomyopia is managed though modification of working conditions, an updated refraction, typically involving a reduction of a myopic prescription to some lower myopic prescription, or through appropriate ocular exercises.

Clinical examination will show an abnormal optic disc, either swollen or atrophic. Optociliary shunt vessels may be seen; the combination of these with progressive visual loss and optic disc atrophy is known as the Hoyt-Spencer triad. Visual acuity is usually but not always reduced.

When ONSM is suspected, MRI of the brain or orbits should be performed. This will usually show characteristic findings and confirm the diagnosis.

ONSM does not improve without treatment. In many cases, there is gradual progression until vision is lost in the affected eye. However, this takes at least several months to occur, and a minority of patients remain stable for a number of years.

Differential diagnosis includes Angelman syndrome, Mowat–Wilson syndrome and Rett syndrome.

Diagnosis is made by showing a mutation in the TCF4 gene.

Around 50% of those affected show abnormalities on brain imaging. These include hypoplastic corpus callosum with a missing rostrum and posterior part of the splenium with bulbous caudate nuclei bulging towards the frontal horns.

Electroencephalograms show an excess of slow components.

All have low levels of immunoglobulin M (IgM) but features of an immunodeficiency are absent.

Once a patient complains of dysphagia they should have an "upper endoscopy" (EGD). Commonly patients are found to have esophagitis and may have an esophageal stricture. Biopsies are usually done to look for evidence of esophagitis even if the EGD is normal. Usually no further testing is required if the diagnosis is established on EGD. Repeat endoscopy may be needed for follow up.

If there is a suspicion of a proximal lesion such as:

- history of surgery for laryngeal or esophageal cancer

- history of radiation or irritating injury

- achalasia

- Zenker's diverticulum

a "barium swallow" may be performed before endoscopy to help identify abnormalities that might increase the risk of perforation at the time of endoscopy.

If achalasia suspected an upper endoscopy is required to exclude a malignancy as a cause of the findings on barium swallow. Manometry is performed next to confirm. A normal endoscopy should be followed by manometry, and if manometry is also normal, the diagnosis is functional dysphagia.

The symptoms due to bleeding are hematemesis and/or melena.

A Dieulafoy's lesion is difficult to diagnose, because of the intermittent pattern of bleeding. Endoscopically it is not easy to recognize and therefore sometimes multiple views have to be performed over a longer period. Today angiography is a good additional diagnostic, but then it can only be seen during a bleeding at that exact time.

The patient is generally sent for a GI, pulmonary, or ENT, depending on the suspected underlying cause. Consultations with a speech therapist and registered dietitian nutritionist (RDN) are also needed, as many patients may need dietary modifications such as thickened fluids.

Genetic counseling is often recommended to provide more information about fetal CPCs, to answer questions and concerns, and to outline available options such as amniocentesis or a blood test from the mother. There is a possible association between ultrasound-detected fetal CPCs and Trisomy 18. It is not correlated to the presence of Trisomy 21 (Down syndrome).

Generally the risks are very low if there are no other risk factors. If no additional abnormalities are detected by a thorough "level II" ultrasound, the likelihood the fetus has trisomy 18 is very low.

A meta-analysis of 8 studies between 1990 and 2000 with choroid plexus cysts that were identified in second-trimester (an incidence of 1.2%). The incidence of the cysts in women younger than 35 was 1% (n=1017). The study found no cases of trisomy 18 in fetuses with cysts whose mother was younger than 35. The study concluded that "there is no evidence that detection of isolated choroid plexus cyst in women who are <35 years of age increases the risk of trisomy 18".

Other factors which may have a bearing on the baby's chances of developing chromosome problems include:

- mother's age at the expected date of delivery

- the results of serum screening; XAFP triple testing or quad screening

- evidence of other "fetal findings" seen at the time of the ultrasound that may suggest a chromosome problem

Following urethroplasty, patients should be monitored for a minimum of 1 year, since the vast majority of recurrences occur within 1 year.

Because of the high rate of recurrence following dilation and other endoscopic approaches, the provider must maintain a high index of suspicion for recurrence when the patient presents with obstructive voiding symptoms or urinary tract infection.

Patients typically present with either an intermittent mass, localized pain, or signs of bowel obstruction. Ultrasonography or a CT scan can establish the diagnosis, although CT scan provides the greatest sensitivity and specificity.

Urethroplasty refers to any open reconstruction of the urethra. Success rates range from 85% to 95% and depend on a variety of clinical factors, such as stricture as the cause, length, location, and caliber. Urethroplasty can be performed safely on men of all ages.

In the posterior urethra, anastomotic urethroplasty (with or without preservation of bulbar arteries) is typically performed after removing scar tissue.

In the bulbar urethra, the most common types of urethroplasty are anastomotic (with or without preservation of corpus spongiosum and bulbar arteries) and substitution with buccal mucosa graft, full-thickness skin graft, or split thickness skin graft. These are nearly always done in a single setting (or stage).

In the penile urethra, anastomotic urethroplasties are rare because they can lead to chordee (penile curvature due to a shortened urethra). Instead, most penile urethroplasties are substitution procedures utilizing buccal mucosa graft, full-thickness skin graft, or split thickness skin graft. These can be done in one or more setting, depending on stricture location, severity, cause and patient or surgeon preference.

The mortality rate for Dieulafoy's was much higher before the era of endoscopy, where open surgery was the only treatment option.

Several radiographic findings are suggestive of DES, such as a "rosary bead esophagus" or "corkscrew" appearance on barium swallow x-ray, although these findings are not unique to DES.

Strictures tend to be diagnosed based on difficulty with insertion and manipulation during sialendoscopy, or by sialography or ultrasound.

Diagnosis is contemplated based upon patient symptoms. Diagnosis is confirmed during intravenous urography, by obtaining erect and supine films. The renal DMSA scan may show decreased counts in the sitting position compared with supine scan.

These hernias should be repaired because of the high risk of strangulation; fortunately, surgery is straightforward, with only larger defects requiring a mesh prosthesis. Varied Spigelian hernia mesh repair techniques have been described, although evidence suggests laparoscopy results in less morbidity and shorter hospitalization compared with open procedures. Mesh-free laparoscopic suture repair is feasible and safe. This novel uncomplicated approach to small Spigelian hernias combines the benefits of laparoscopic localization, reduction, and closure without the morbidity and cost associated with foreign material.