Glaucoma

Glaucoma in rabbits is a serious ocular condition characterized by elevated intraocular pressure that causes progressive damage to the optic nerve and internal eye structures, ultimately leading to vision loss if left untreated. This condition occurs when the normal balance between aqueous humor production and drainage becomes disrupted, causing fluid to accumulate within the eye and pressure to rise. Unlike in humans and dogs where glaucoma is relatively common, glaucoma in rabbits is less frequently encountered but carries significant implications when it does occur. The condition may develop as a primary disease due to inherited abnormalities in the drainage structures, or more commonly as a secondary complication of other ocular conditions including uveitis, lens disease, or E. cuniculi infection.

The pathophysiology of glaucoma involves the accumulation of aqueous humor, the clear fluid that fills the front portion of the eye and provides nutrients to avascular structures. This fluid is continuously produced by the ciliary body and normally drains through a specialized structure called the iridocorneal angle, located where the iris meets the cornea. When drainage is impaired by anatomical abnormalities, inflammatory debris, lens material, or other factors, pressure builds within the eye. Elevated intraocular pressure compresses blood vessels supplying the optic nerve and retina, leading to ischemic damage, while direct pressure effects damage nerve fibers. The result is progressive and irreversible loss of vision that begins peripherally and advances toward central vision.

The impact of glaucoma on rabbit health and welfare is substantial, primarily due to the pain associated with elevated intraocular pressure. Unlike chronic glaucoma in humans that may be painless in early stages, rabbits with glaucoma often experience significant discomfort that affects their quality of life. Because rabbits instinctively hide signs of pain and illness, the condition may be quite advanced before owners recognize a problem. Affected rabbits may show subtle changes in behavior, reduced appetite, or decreased activity that can easily be attributed to other causes. As the disease progresses and the eye enlarges, the cosmetic changes become more obvious, but by this stage significant damage has usually occurred. Early detection through routine examination by a rabbit-savvy veterinarian is essential for the best outcomes.

Treatment of glaucoma in rabbits focuses on reducing intraocular pressure to prevent further optic nerve damage and managing pain to maintain quality of life. Medical management using topical pressure-lowering medications can be effective in some cases, particularly when initiated early. Surgical options including laser procedures, drainage implants, or removal of the affected eye may be necessary when medical management fails or is impractical. The prognosis for vision preservation depends heavily on how early treatment is initiated and whether the underlying cause can be addressed. For eyes that have already lost vision, treatment goals shift to maintaining comfort, which may ultimately require enucleation. Consultation with a veterinary ophthalmologist is strongly recommended for accurate diagnosis and treatment planning.

Primary glaucoma in rabbits results from inherited developmental abnormalities in the iridocorneal angle, the specialized drainage structure responsible for aqueous humor outflow. This form of glaucoma has been well-documented in New Zealand White rabbits, where an autosomal recessive gene causes goniodysgenesis, a malformation of the drainage angle that impedes fluid outflow. Affected rabbits are typically born with the abnormality, and glaucoma develops over time as the inadequate drainage becomes progressively unable to keep up with aqueous humor production. The age of onset varies but often occurs in young adult rabbits. Other breeds may carry similar genetic predispositions, though these have been less extensively studied than in New Zealand Whites. Primary glaucoma typically affects both eyes, though one may become clinically apparent before the other.

Secondary glaucoma, which is more common overall in pet rabbits than primary glaucoma, develops as a consequence of other ocular diseases that interfere with aqueous drainage. The most significant cause is lens-related disease, particularly lens rupture from E. cuniculi infection, which releases lens proteins into the anterior chamber and triggers severe inflammation that blocks the drainage angle. Phacoclastic uveitis following lens rupture represents one of the most frequent pathways to secondary glaucoma in rabbits. Other forms of anterior uveitis from any cause, including bacterial infection associated with dental disease, trauma, or immune-mediated inflammation, can similarly obstruct drainage with inflammatory debris and cells.

Lens displacement from its normal position, whether from trauma, E. cuniculi weakening of supporting structures, or other causes, can physically block the drainage angle or pupil and cause pressure elevation. Intraocular tumors, though relatively uncommon in rabbits, can obstruct drainage pathways or directly produce fluid that overwhelms drainage capacity. Prior ocular surgery, particularly procedures involving the lens or anterior chamber, may result in scarring or other changes that impair drainage. Prolonged topical corticosteroid use, while less commonly implicated in rabbits than in some other species, may contribute to pressure elevation in susceptible individuals.

The mechanism of glaucoma development involves a critical imbalance in aqueous humor dynamics. The ciliary body continuously produces approximately two to three microliters of aqueous humor per minute in rabbits, and this fluid must drain at an equivalent rate to maintain stable pressure. When outflow resistance increases due to angle abnormalities, inflammatory debris, lens material, or physical obstruction, pressure rises. Normal intraocular pressure in rabbits ranges from approximately 10 to 20 mmHg, though values vary with measurement technique and individual factors. Pressures above 25 to 30 mmHg are generally considered elevated and potentially damaging. Sustained elevation causes compression of blood vessels in the optic nerve head, leading to ischemia and death of retinal ganglion cells whose axons form the optic nerve.

Risk factors for glaucoma development include breed predisposition, particularly in New Zealand Whites and potentially related breeds, presence of ocular inflammation from any cause, E. cuniculi infection with lens involvement, history of ocular trauma, and advanced age. Rabbits with known predisposing conditions such as cataracts, especially those associated with E. cuniculi, should be monitored closely for glaucoma development. Any rabbit with anterior uveitis is at risk and should have intraocular pressure assessed regularly. Early identification of risk factors allows for heightened surveillance and early intervention when pressure begins to rise.

Early warning signs of glaucoma in rabbits are often subtle and easily overlooked, particularly because rabbits instinctively hide signs of pain and weakness. Initial symptoms may include mild changes in the eye's appearance that are apparent only on close inspection, such as slight haziness of the cornea or mild redness around the eye. Behavioral changes may precede obvious physical signs, with affected rabbits becoming less active, spending more time in hiding areas, or showing subtle changes in appetite. Some rabbits may squint or hold the affected eye partially closed, particularly in bright light. Head pressing or reluctance to have the head touched may indicate discomfort. Because these early signs are nonspecific, glaucoma in its earliest stages is most often detected during routine veterinary examinations through tonometry rather than owner observation.

As glaucoma progresses and intraocular pressure rises, more obvious symptoms develop. Corneal edema causes the normally clear cornea to become cloudy or bluish, sometimes described as a steamy or ground-glass appearance. This cloudiness may be the first change that alerts owners to a problem. The affected eye may begin to appear larger than the normal eye, a change called buphthalmos that results from stretching of the eye wall under increased pressure. The pupil may become dilated and respond poorly or not at all to light. Blood vessels on the surface of the eye may become more prominent, and the eye may appear red and inflamed. These visible changes often prompt veterinary consultation.

Behavioral changes associated with glaucoma reflect both vision loss and pain. Rabbits with unilateral disease may show altered responses to stimuli on the affected side, failing to notice movement or being more easily startled. Those with bilateral involvement may become hesitant in their movements, bump into objects, or show reluctance to jump onto or off of surfaces. Activity levels typically decrease as affected rabbits experience discomfort and vision impairment. Social behavior may change, with affected rabbits becoming more withdrawn or more dependent on bonded companions. Some rabbits show decreased grooming or altered grooming patterns. Reduced food intake is particularly concerning in rabbits and may reflect pain-associated anorexia; any decrease in eating must be addressed promptly to prevent secondary GI stasis.

Physical examination findings in glaucoma cases depend on the severity and duration of disease. Tonometry reveals elevated intraocular pressure, often significantly above the normal range of 10 to 20 mmHg. Direct ophthalmoscopy may show changes in the optic nerve head, including cupping and pallor that indicate nerve damage. In advanced cases, the optic nerve may appear severely atrophied. Gonioscopy, which examines the drainage angle, may reveal developmental abnormalities in primary glaucoma or inflammatory changes in secondary cases. If an underlying cause is present, such as lens rupture or uveitis, findings related to that condition will also be observed. Both eyes should be thoroughly examined as bilateral involvement is common in primary glaucoma and may develop in secondary cases.

Symptom progression in glaucoma typically follows a pattern of gradual worsening, though acute episodes with rapid pressure elevation can occur. Chronic, moderately elevated pressure causes progressive damage over weeks to months, with gradual enlargement of the eye, progressive corneal changes, and advancing vision loss. Acute pressure spikes may cause sudden onset of severe signs including marked corneal edema, fixed dilated pupil, and obvious pain. The end stage of uncontrolled glaucoma is a blind, enlarged, often painful eye that may be prone to corneal ulceration due to incomplete eyelid coverage. Some end-stage eyes eventually become soft and shrunken through a process called phthisis bulbi, though this may take many months to years.

Emergency symptoms requiring immediate veterinary attention include sudden onset of severe corneal cloudiness, acute eye enlargement, obvious severe pain manifested by teeth grinding or complete inappetence, or any acute change in a previously stable glaucomatous eye. A rabbit that stops eating for more than 12 hours faces life-threatening GI stasis regardless of the cause and requires emergency care. Any rabbit showing signs of severe distress, collapse, or dramatic behavioral change needs immediate evaluation. If an owner notices rapid progression of any eye abnormality over hours to days, prompt consultation is warranted as acute glaucoma can cause permanent damage within a very short time frame.

Diagnosis of glaucoma in rabbits relies primarily on measurement of intraocular pressure using specialized instruments. Tonometry, the measurement of eye pressure, can be performed using several different devices. Applanation tonometry using instruments like the Tonopen is commonly used in small animal practice and provides reliable measurements in rabbits. Rebound tonometry using the Tonovet is another accurate method that is well-tolerated by rabbits due to the minimal corneal contact required. Normal intraocular pressure in rabbits generally ranges from 10 to 20 mmHg, though reference ranges vary somewhat with technique and individual factors. Pressures consistently above 25 to 30 mmHg, particularly when accompanied by clinical signs, support a diagnosis of glaucoma. Serial measurements over time may be needed to document elevated pressure, as single readings can be affected by handling stress.

Comprehensive ophthalmic examination by a veterinarian, ideally a veterinary ophthalmologist, provides essential additional information for diagnosis and treatment planning. External examination assesses eye size, symmetry, and surface changes. Slit lamp biomicroscopy allows detailed evaluation of the cornea, anterior chamber, iris, and lens. Gonioscopy, which uses a special lens to visualize the drainage angle, can identify developmental abnormalities characteristic of primary glaucoma or inflammatory changes suggesting secondary disease. Direct and indirect ophthalmoscopy evaluate the optic nerve head and retina when media clarity permits. Advanced imaging such as ultrasound biomicroscopy can visualize angle structures when corneal edema prevents direct examination. Ocular ultrasound helps evaluate internal eye structures, detect masses, and assess lens position.

Identifying the underlying cause of glaucoma is crucial for appropriate treatment. In cases of suspected secondary glaucoma, thorough evaluation for predisposing conditions is essential. E. cuniculi serology helps identify this common cause of lens-induced uveitis in rabbits. Complete ophthalmic examination of both eyes detects lens abnormalities, uveitis, or other potential causes. Skull radiographs may be indicated if dental disease is suspected as a source of ocular infection. Systemic evaluation including blood work assesses overall health and may detect conditions contributing to ocular disease. History taking should explore any prior eye problems, trauma, or illness that might be relevant.

Differential diagnosis for an enlarged or cloudy eye in rabbits includes several conditions that must be distinguished from glaucoma. Buphthalmos with normal pressure may occur as a congenital abnormality without glaucoma. Corneal edema from other causes, including endothelial disease or trauma, can mimic the corneal cloudiness of glaucoma but occurs without pressure elevation. Uveitis without secondary glaucoma causes eye inflammation but typically with normal or low intraocular pressure. Exophthalmos, where the eye protrudes due to a retrobulbar process such as an abscess, must be distinguished from buphthalmos, which is enlargement of the globe itself. Accurate tonometry is the key diagnostic tool for confirming glaucoma, and examination by a veterinary ophthalmologist helps distinguish among these conditions and identify the specific type and cause of glaucoma present.

Emergency treatment for acute glaucoma or acute pressure spikes in chronic glaucoma focuses on rapidly lowering intraocular pressure to minimize ongoing damage. Intravenous mannitol may be administered to cause osmotic reduction in aqueous humor volume and provide temporary pressure relief. Topical pressure-lowering medications are initiated immediately and often used in combination for maximal effect. Pain management is essential as acute glaucoma is extremely painful; systemic analgesics such as meloxicam at appropriate rabbit doses provide comfort while awaiting pressure reduction. If the rabbit has stopped eating due to pain, supportive care including syringe feeding with critical care formula and fluid support must be initiated immediately to prevent GI stasis. Acute glaucoma requires intensive monitoring and frequent reassessment as permanent damage can occur within hours to days.

Medical management of glaucoma uses topical medications to reduce aqueous humor production or increase outflow. Carbonic anhydrase inhibitors such as dorzolamide or brinzolamide decrease aqueous production and are commonly used in rabbits. Beta-blockers like timolol also reduce aqueous production and may be used alone or in combination with carbonic anhydrase inhibitors. Combination products containing both drug classes simplify dosing. Prostaglandin analogs, which work by increasing alternative outflow pathways, are effective in some species but their efficacy in rabbits is less established. Topical medications typically require administration two to three times daily, and owner compliance is essential for success. Response to medical therapy should be monitored through regular tonometry, initially weekly or biweekly until pressure is stabilized.

Surgical intervention becomes necessary when medical management fails to adequately control pressure or is impractical for the owner to maintain. Laser cyclophotocoagulation uses laser energy to destroy portions of the ciliary body, reducing aqueous production. This procedure can be performed with various laser types and may be repeated if initial treatment is insufficient. Gonioimplant surgery involves placing a drainage device to shunt aqueous humor from the anterior chamber to an external reservoir, bypassing the obstructed natural drainage pathway. These procedures require specialized equipment and expertise and are typically performed by veterinary ophthalmologists. Anesthesia in rabbits requires an experienced team familiar with rabbit-specific considerations, including the prohibition on pre-anesthetic fasting.

Enucleation, surgical removal of the eye, represents the definitive treatment for painful, blind glaucomatous eyes that cannot be controlled medically. While this option may seem extreme, it eliminates pain and the need for ongoing medication in eyes that have lost function. Rabbits adapt remarkably well to life with one eye, and quality of life often improves dramatically following removal of a painful blind eye. The procedure requires general anesthesia and involves removal of the entire globe, with closure of the eyelids over the orbital space. Recovery is typically straightforward, with most rabbits returning to normal activity within one to two weeks. Evisceration with intrascleral prosthesis is an alternative that preserves the external shell of the eye for cosmesis, though this is less commonly performed in rabbits.

Supportive care throughout glaucoma treatment addresses comfort and overall health. Pain management using rabbit-safe medications is essential, as uncontrolled pain reduces appetite and quality of life. Nutritional support ensures adequate food intake, with syringe feeding initiated if appetite decreases. Environmental modifications may help rabbits with vision impairment navigate safely. Protection from self-trauma to the eye, particularly during acute phases or following procedures, may require temporary use of recovery collars modified to allow cecotrophy. Gut motility support may be needed if stress or reduced activity affects digestive function.

Treatment decisions must balance multiple factors including potential for vision preservation, pain control, quality of life, owner resources, and practicality of ongoing care. Eyes with documented optic nerve damage and vision loss are unlikely to regain useful sight regardless of pressure control, shifting treatment goals to comfort. Medical management requires commitment to long-term medication administration and regular monitoring. Surgical options involve significant cost and require access to specialist care. Frank discussions with the veterinary team about realistic expectations help owners make informed decisions that serve their rabbit's best interests. Quality of life must remain the primary consideration in all treatment planning.

Recovery timelines for rabbits with glaucoma depend on the treatment approach and underlying cause. Medical management, when successful, can stabilize pressure within days to weeks, with ongoing medication required indefinitely in most cases. Adjustment of medication types and doses may be needed over the initial weeks to months to achieve optimal control. Recovery following laser surgery typically involves two to four weeks of intensive medical therapy while the treated tissue responds, followed by gradual reduction in medications if adequate pressure control is achieved. Recovery from enucleation is often remarkably rapid, with most rabbits showing dramatically improved comfort within days of surgery and returning to normal activity within one to two weeks. The absence of a painful, blind eye frequently results in more energetic, engaged behavior as rabbits are no longer coping with chronic discomfort.

Post-treatment care requirements vary by intervention. Medically managed rabbits require consistent medication administration, typically two to three times daily indefinitely. Regular veterinary monitoring through tonometry and ophthalmic examination tracks treatment efficacy and detects complications early. Following surgical procedures, intensive topical medication is usually required for several weeks. Post-enucleation care involves incision monitoring, pain management, and activity restriction during initial healing, typically for one to two weeks. All glaucoma patients need close attention to appetite and digestive function, as any reduction in eating risks GI stasis. Syringe feeding should be initiated promptly if food intake decreases, and veterinary guidance sought if feeding problems persist.

Prognosis for rabbits with glaucoma varies considerably based on type, cause, and treatment timing. Primary glaucoma caught early and managed effectively may allow years of retained vision, though progression despite treatment is common. Secondary glaucoma prognosis depends heavily on whether the underlying cause can be controlled; lens-induced uveitis following E. cuniculi often results in progressive disease despite treatment. Eyes that have already lost vision at the time of diagnosis will not regain sight regardless of treatment success. For these eyes, prognosis relates to comfort rather than vision, with good outcomes achievable through appropriate medical management or enucleation. Early detection and intervention consistently correlate with better outcomes, emphasizing the importance of regular veterinary examination and prompt attention to any eye changes.

Long-term outlook for rabbits with glaucoma requires ongoing vigilance and care. Medically controlled cases need lifelong monitoring with regular tonometry to detect treatment failure or disease progression. The fellow eye requires careful surveillance in primary glaucoma cases, as bilateral involvement is expected, and in secondary cases where the underlying cause might affect both eyes. Even successfully controlled glaucoma can progress over time, and medication regimens may need adjustment. Quality of life monitoring should assess not just eye health but overall rabbit wellbeing, with treatment approaches modified if they become burdensome. Many rabbits with glaucoma, including those who have lost one or both eyes, can maintain excellent quality of life for their normal lifespan with appropriate management.

Primary prevention of inherited glaucoma centers on responsible breeding practices, particularly in New Zealand White rabbits and related breeds known to carry genetic predisposition. Affected rabbits and known carriers should be excluded from breeding programs to reduce the frequency of the causative genes in the population. Screening breeding animals through ophthalmic examination and gonioscopy can identify rabbits with abnormal drainage angles before they are used for breeding. Prospective rabbit owners should inquire about eye health history when obtaining rabbits from breeders, particularly for breeds with known glaucoma risk. However, complete prevention of inherited disease is challenging, and genetic testing for the specific mutations is not yet widely available in rabbits.

Prevention of secondary glaucoma focuses on managing conditions that can lead to pressure elevation. Prompt treatment of uveitis from any cause minimizes inflammatory damage to drainage structures. Appropriate management of E. cuniculi infection, including treatment with fenbendazole when indicated, may reduce the risk of lens rupture and subsequent phacoclastic uveitis that commonly leads to glaucoma. Regular veterinary monitoring of rabbits with cataracts or other lens abnormalities allows early detection of complications. Protecting rabbits from eye trauma through appropriate housing, supervision during exercise, and careful introduction of new companions reduces the risk of traumatic uveitis and its sequelae.

Maintaining overall ocular health supports prevention of conditions that predispose to glaucoma. Regular veterinary examinations including eye assessment allow early detection of problems before they progress. Dental health maintenance is important as dental disease can lead to ocular infection and uveitis. Optimal nutrition supports immune function and general health. Environmental factors including appropriate lighting, clean housing, and absence of irritants help maintain eye health. Prompt veterinary attention for any eye abnormality, including redness, discharge, cloudiness, or behavioral changes suggesting vision problems, enables early intervention.

Rabbits at elevated risk for glaucoma benefit from enhanced monitoring protocols. Those with known predisposing conditions including cataracts, history of uveitis, or E. cuniculi infection should have regular tonometry performed, with frequency determined by their specific risk level and any clinical changes. New Zealand White rabbits and those with New Zealand White ancestry should be monitored even in the absence of symptoms given their genetic predisposition. Baseline tonometry values in adult rabbits provide reference points for detecting early pressure elevation. Owners should be educated about signs of glaucoma so they can seek prompt attention if changes are noticed between scheduled examinations.

Early intervention when glaucoma is detected offers the best chance of preserving vision and comfort. Initiating treatment at the earliest sign of pressure elevation, before significant optic nerve damage has occurred, provides the best visual outcomes. Regular monitoring of rabbits on glaucoma therapy allows timely treatment adjustments when pressure control deteriorates. Owner education about the importance of consistent medication administration and monitoring schedules supports treatment success. Having a relationship established with a rabbit-savvy veterinarian, and ideally access to veterinary ophthalmology consultation, ensures appropriate care is available when needed.

Daily management of a rabbit with glaucoma requires commitment to medication schedules and ongoing monitoring. Topical eye medications typically need administration two to three times daily, and consistency is essential for effective pressure control. Developing a routine helps ensure doses are not missed, and keeping medications in a visible location serves as a reminder. Administering eye drops requires gentle restraint and careful technique to ensure the medication enters the eye; owners should receive instruction from their veterinary team and practice until confident. Monitoring the eye daily for changes in appearance, size, or comfort level helps detect problems early. Food intake and fecal output should be tracked as indicators of overall wellbeing, with any decrease in eating addressed promptly through veterinary consultation and supportive feeding as needed.

Home environment modifications support safety and quality of life for rabbits with vision impairment from glaucoma. Consistent placement of furniture, food, water, and litter boxes allows rabbits to navigate using memory. Removing sharp edges and blocking access to stairs or drop-offs prevents injury. Non-slip surfaces provide traction and orientation cues. Adequate but not harsh lighting helps rabbits with residual vision maximize their remaining sight. Quiet, low-stress environments reduce startle responses and anxiety. If glaucoma affects only one eye, keeping items and approaches on the sighted side when possible helps the rabbit track activities. Bonded companions often help visually impaired rabbits navigate and provide social support that reduces anxiety.

Quality of life assessment should guide ongoing management decisions. Signs of good quality of life include interest in food and treats, willingness to move about and explore within their comfort zone, normal grooming behavior, relaxed body language during rest, and positive social interactions. Signs of compromised quality of life include persistent pain behaviors such as teeth grinding or hunched posture, reluctance to move, decreased appetite despite intervention, social withdrawal, and poor coat condition from reduced grooming. Pain in glaucoma may manifest subtly, and owners should communicate any concerns to their veterinary team. If quality of life cannot be maintained with current treatment, modifications or alternative approaches including enucleation should be discussed.

Ongoing monitoring and veterinary follow-up ensure treatment remains effective and complications are detected early. Tonometry should be performed regularly, with frequency depending on disease stability, typically monthly initially and then every two to three months for well-controlled cases. Complete ophthalmic examination accompanies pressure checks to assess for progression or complications. The fellow eye requires ongoing surveillance for development of glaucoma, particularly in primary cases. General health monitoring including weight checks and assessment of eating and elimination habits helps ensure overall wellbeing. Keeping records of medications, pressure readings, and any concerns or changes helps the veterinary team track the rabbit's course.

Caregiver support and resources help rabbit owners manage the demands of caring for a rabbit with chronic disease. The House Rabbit Society provides information and connects owners with local resources. Online communities offer peer support and practical advice from others managing similar conditions. Managing glaucoma requires financial investment for medications, regular veterinary visits, and potentially specialist consultations or surgical procedures. Having realistic expectations about outcomes while maintaining hope for quality of life helps owners make sustainable decisions. Recognizing the emotional toll of caring for a chronically ill pet and seeking support when needed benefits both owners and their rabbits. Open communication with the veterinary team about concerns, limitations, and goals ensures treatment plans align with what is achievable and appropriate for each individual situation.

New Zealand White rabbits demonstrate the highest genetic predisposition to primary glaucoma among domestic rabbit breeds. Research has identified an autosomal recessive inheritance pattern for goniodysgenesis in this breed, with affected animals showing malformation of the drainage structures that leads to progressive pressure elevation. The condition typically develops in young adult New Zealand Whites, though age of onset varies. Because New Zealand Whites have been extensively used in laboratory settings, much of the existing research on rabbit glaucoma comes from this population. Related breeds that may share genetic background with New Zealand Whites, including some commercial meat breeds, might carry similar risk, though less data is available for these populations.

Beyond breed-specific genetic predisposition to primary glaucoma, secondary glaucoma can affect rabbits of any breed when predisposing conditions are present. Breeds with increased risk of E. cuniculi-associated lens disease face elevated risk of secondary glaucoma from phacoclastic uveitis. Dwarf breeds with predisposition to hereditary cataracts may develop glaucoma if lens problems progress to complications. Lop breeds, which have elevated rates of dental disease, may face increased risk of uveitis and subsequent glaucoma if dental infections spread to affect the eye. Essentially, any breed that is prone to conditions causing ocular inflammation faces some increased risk of secondary glaucoma development.

Screening recommendations vary based on risk level. New Zealand White rabbits and those with known New Zealand White ancestry should receive baseline ophthalmic examination including tonometry as young adults, with periodic reassessment thereafter. Breeding animals from this breed should undergo gonioscopy to assess drainage angle anatomy, with affected animals excluded from breeding programs. For other breeds, screening recommendations focus on monitoring for conditions that predispose to secondary glaucoma. Rabbits with known cataracts, history of uveitis, E. cuniculi infection, or other ocular disease should have regular tonometry. Any rabbit showing signs of eye problems should receive comprehensive ophthalmic evaluation including pressure measurement. Early detection through appropriate screening allows intervention before irreversible damage occurs.

Glaucoma in rabbits most commonly occurs secondary to other ocular conditions, making co-occurrence with predisposing diseases extremely common. E. cuniculi-associated lens disease, particularly phacoclastic uveitis following lens rupture, represents the most frequent precursor to secondary glaucoma in pet rabbits. Uveitis from any cause, including bacterial infection associated with dental disease, trauma, or immune-mediated inflammation, can lead to inflammatory glaucoma through obstruction of drainage pathways. Cataracts of any etiology may be complicated by lens-induced uveitis and subsequent glaucoma, particularly when lens protein leaks through the capsule. Lens luxation, either primary or secondary to E. cuniculi or trauma, can physically obstruct the pupil or drainage angle and cause acute pressure elevation. Managing these underlying conditions aggressively may help prevent or delay glaucoma development.

Several conditions may present with similar signs to glaucoma and must be differentiated through proper examination. Buphthalmos, or enlargement of the eye, can occur as a congenital abnormality without pressure elevation and should be distinguished from glaucomatous buphthalmos through tonometry. Exophthalmos, protrusion of a normal-sized eye due to retrobulbar disease such as abscess, must be differentiated from true globe enlargement. Corneal edema from endothelial dysfunction or trauma may mimic glaucoma but occurs without pressure elevation. Uveitis causes eye inflammation that may appear similar to the redness seen in glaucoma, but typically produces low or normal intraocular pressure rather than elevation. Accurate diagnosis through comprehensive examination including tonometry ensures appropriate treatment.

Complications of glaucoma can cause additional problems requiring management. Progressive optic nerve damage leads to irreversible vision loss that may be partial initially but often becomes complete. Lens luxation can occur as a consequence of globe enlargement and zonular stretching, potentially worsening pressure control. Corneal ulceration may develop in buphthalmic eyes where the enlarged cornea cannot be fully protected by the eyelids. Exposure keratitis occurs when eyelid closure is incomplete. Phthisis bulbi, shrinkage and degeneration of the globe, represents the end stage of some chronic glaucoma cases. GI stasis can develop secondary to pain, stress, and reduced appetite in any rabbit with ocular disease, requiring vigilant monitoring of food intake and digestive function. The potential for these complications emphasizes the importance of appropriate treatment to maintain comfort and prevent secondary problems.