Cultures are not often taken or needed as most cases resolve either with time or typical antibiotics. Swabs for bacterial culture are necessary if the history and signs suggest bacterial conjunctivitis but there is no response to topical antibiotics. Viral culture may be appropriate in epidemic case clusters.

A patch test is used to identify the causative allergen in the case where conjunctivitis is caused by allergy.

Conjunctival scrapes for cytology can be useful in detecting chlamydial and fungal infections, allergy, and dysplasia, but are rarely done because of the cost and the general lack of laboratory staff experienced in handling ocular specimens. Conjunctival incisional biopsy is occasionally done when granulomatous diseases ("e.g.", sarcoidosis) or dysplasia are suspected.

Classification can be either by cause or by extent of the inflamed area.

Treatment of herpes of the eye is different based on its presentation: epithelial keratitis is caused by live virus while stromal disease is an immune response and metaherpetic ulcer results from inability of the corneal epithelium to heal:

A specific clinical diagnosis of HSV as the cause of dendritic keratitis can usually be made by ophthalmologists and optometrists based on the presence of characteristic clinical features. Diagnostic testing is seldom needed because of its classic clinical features and is not useful in stromal keratitis as there is usually no live virus. Laboratory tests are indicated in complicated cases when the clinical diagnosis is uncertain and in all cases of suspected neonatal herpes infection:

- Corneal smears or impression cytology specimens can be analyzed by culture, antigen detection, or fluorescent antibody testing. Tzanck smear, i.e.Papanicolaou staining of corneal smears, show multinucleated giant cells and intranuclear inclusion bodies, however, the test is low in sensitivity and specificity.

- DNA testing is rapid, sensitive and specific. However, its high cost limits its use to research centers.

- Demonstration of HSV is possible with viral culture.

- Serologic tests may show a rising antibody titer during primary infection but are of no diagnostic assistance during recurrent episodes.

The disease incidence varies widely depending on the geographical location. The most extensive epidemiological survey on this subject has been carried out by Dharmasena et al. who analysed the number of neonates who developed neonatal conjunctivitis in England from 2000 to 2011. In addition to the incidence of this sight threatening infection they also investigated the time trends of the disease. According to them the incidence of Neonatal conjunctivitis (Ophthalmia Neonatorum) in England was 257 (95% confidence interval: 245 to 269) per 100,000 in 2011.

Diagnosis of FVR is usually by clinical signs, especially corneal ulceration. Definitive diagnosis can be done by direct immunofluorescence or virus isolation. However, many healthy cats are subclinical carriers of feline herpes virus, so a positive test for FHV-1 does not necessarily indicate that signs of an upper respiratory tract infection are due to FVR. Early in the course of the disease, histological analysis of cells from the tonsils, nasal tissue, or nictitating membrane (third eyelid) may show inclusion bodies (a collection of viral particles) within the nucleus of infected cells.

Antibiotic ointment is typically applied to the newborn's eyes within 1 hour of birth as prevention against gonococcal ophthalmia. This maybe erythromycin, tetracycline, or silver nitrate.

Ligneous conjunctivitis may be managed by topical treatments of plasminogen, topical and subconjunctival fresh frozen plasma, and fibrinolytic therapy.

Scleritis is best detected by examining the sclera in daylight; retracting the lids helps determine the extent of involvement. Other aspects of the eye exam (i.e. visual acuity testing, slit lamp examination, etc.) may be normal. Scleritis may be differentiated from episcleritis by using phenylephrine or neosynephrine eye drops, which causes blanching of the blood vessels in episcleritis, but not in scleritis.

Ancillary tests CT scans, MRIs, and ultrasonographies can be helpful, but do not replace the physical examination.

There is a vaccine for FHV-1 available (ATCvet code: , plus various combination vaccines), but although it limits or weakens the severity of the disease and may reduce viral shedding, it does not prevent infection with FVR. Studies have shown a duration of immunity of this vaccine to be at least three years. The use of serology to demonstrate circulating antibodies to FHV-1 has been shown to have a positive predictive value for indicating protection from this disease.

Conjunctival concretions can be seen easily by everting the eyelid. The projecting concretions should be removed. Removal is easily performed by a doctor. For example, using needles or sharp knife removes the concretion, under a local light anesthesia of the conjunctiva.

Scleritis can be classified as anterior scleritis and posterior scleritis. Anterior scleritis is the most common variety, accounting for about 98% of the cases. It is of two types : Non-necrotising and necrotising. Non-necrotising scleritis is the most common, and is further classified into diffuse and nodular type based on morphology. Necrotising scleritis accounts for 13% of the cases. It can occur with or without inflammation.

A detailed history allows physicians to determine whether the presenting symptoms are due to an allergen or another source. Diagnostic tests such as conjunctival scrapings to look for eosinophils are helpful in determining the cause of the allergic response. Antihistamines, medication that stabilizes mast cells, and NSAIDs are safe and usually effective. Corticosteroids are reserved for more severe cases of ocular allergy disease, and their use should be monitored by an eye care physician due to possible side-effects. When an allergen is identified, the person should avoid the allergen as much as possible.

If the allergen is encountered and the symptoms are mild, a cold compress can be used to provide relief.

Histopathological findings from affected humans indicate that wound healing is impaired due to a deficiency in plasmin-mediated extracellular fibrinolysis. Episodes may be triggered by minor trauma, eye surgery, or by systemic events such as infections or antifibrinolytic therapy. Histology shows amorphous subepithelial deposits of eosinophilic material consisting predominantly of fibrin.

The diagnosis is made clinically, and usually this is clear cut if the lesion is associated with the flange of a denture. Tissue biopsy is not usually indicated before removal of the lesion, since the excises surgical specimen is usually sent for histopathologic examination and the diagnosis is confirmed retrospectively. Rarely, incisional biopsy may be indicated to rule out neoplasia, e.g. in the presence of suspicious ulceration. The appearance may also be confused with pyogenic granuloma.

The excessive tissue is composed of cellular, inflamed fibrous connective tissue. The appearance of an epulis fissuratum microscopically is an overgrowth of cells from the fibrous connective tissue. The epithelial cells are usually hyperkeratotic and irregular, hyperplastic rete ridges are often seen.

DLK is usually seen after refractive surgery. Neutrophils infiltrate the corneal stroma in a diffuse, multifocal pattern. Infiltration is confined to the surgical flap interface with no posterior or anterior extension, and overlying epithelium most often remains intact. As it is a sterile process, cultures based on swab tests are negative.

Intraocular pressure should be measured as part of the routine eye examination.

It is usually only elevated by iridocyclitis or acute-closure glaucoma, but not by relatively benign conditions.

In iritis and traumatic perforating ocular injuries, the intraocular pressure is usually low.

The basic method for control of the conjunctivitis includes proper hygiene and care for the affected eye. If the conjunctivitis is found to be caused by "H. aegyptius" Biogroup III then prompt antibiotic treatment preferably with rifampin has been shown to prevent progression to BPF. If the infected person resides in Brazil, it is mandatory that the infection is reported to the health authority so that a proper investigation of the contacts can be completed. This investigation will help to determine the probable source of the infection.

Antigen detection, polymerase chain reaction assay, virus isolation, and serology can be used to identify adenovirus infections. Adenovirus typing is usually accomplished by hemagglutination-inhibition and/or neutralization with type-specific antisera. Since adenovirus can be excreted for prolonged periods, the presence of virus does not necessarily mean it is associated with disease.

Depending on severity, therapies may range from topical or oral anti-inflammatories to irrigation and surgical repair.

The "Severity of Illness Score for Toxic Epidermal Necrolysis" (SCORTEN) is a scoring system developed to assess the severity of TEN and predict mortality in patients with acute TEN.

One point is given for each of the following factors:

- age >40

- heart rate >120 beats/minute

- carrying diagnosis of cancer

- separation of epidermis on more than ten percent of body surface area (BSA) on day 1.

- Blood Urea Nitrogen >28 mg/dL

- Glucose >252 mg/dL (14 mmol/L)

- Bicarbonate <20mEq/L

If the causative factor persists, tissue will become more fibrous over time.

The diagnosis is based on tissue examination, e.g. biopsy.

The name of the lesion describes it microscopic appearance. It has nipple-like structures with fibrovascular cores () that are long in relation to their width (villus-like), which are covered with a glandular pseudostratified columnar epithelium.

Definitive diagnosis of TEN often requires biopsy confirmation. Histologically, early TEN shows scattered necrotic keratinocytes. In more advanced TEN, full thickness epidermal necrosis is visualized, with a subepidermal split, and scant inflammatory infiltrate in the papillary dermis. Epidermal necrosis found on histology is sensitive but not specific finding for TEN.