Retrobulbar Abscess

Retrobulbar abscess is a serious bacterial infection occurring in the space behind the eyeball in guinea pigs, typically causing dramatic forward protrusion of the affected eye along with significant pain and systemic illness. This condition is one of the most common serious eye problems encountered in guinea pig medicine and represents a true veterinary emergency requiring prompt diagnosis and aggressive treatment. The term retrobulbar literally means behind the globe of the eye, referring to the orbital space where the abscess develops and expands, pushing the eye forward as infected material accumulates. Understanding this condition is essential for guinea pig owners as early recognition and rapid treatment significantly impact outcomes.

The overwhelming majority of retrobulbar abscesses in guinea pigs develop secondary to dental disease, reflecting the unique anatomical relationship between guinea pig teeth and the orbit. Guinea pigs have continuously growing teeth with very long roots, particularly of the upper cheek teeth (molars and premolars), which extend upward toward and sometimes into the thin bony floor of the orbit. When dental problems lead to tooth root infections or periapical abscesses, bacteria can readily spread into the orbital space, establishing the retrobulbar infection. This connection between dental and ocular health is so strong that any guinea pig presenting with a retrobulbar abscess should be assumed to have underlying dental disease until proven otherwise.

The impact of retrobulbar abscess on a guinea pig's health is profound and extends far beyond local eye problems. The infection causes significant pain that typically results in decreased appetite, which in these obligate hindgut fermenters quickly leads to dangerous gastrointestinal stasis. Systemic spread of infection can cause septicemia, and the proximity to the brain creates risk of meningitis or brain abscess in severe cases. Without treatment, retrobulbar abscess is invariably fatal, and even with treatment, the condition carries significant morbidity. The pain, systemic illness, and stress associated with this condition make it one of the most distressing presentations seen in guinea pig practice.

Early detection and aggressive treatment of retrobulbar abscess are critical for survival and recovery. Because guinea pigs instinctively hide illness until severely compromised, owners must be vigilant for subtle early signs that could indicate developing problems. Any eye protrusion, facial swelling, changes in eating behavior, or signs of oral discomfort should prompt immediate veterinary evaluation. With prompt diagnosis and appropriate treatment combining medical and often surgical approaches, many guinea pigs can recover from retrobulbar abscess, though treatment is intensive and recurrence is possible if underlying dental disease is not adequately addressed.

The primary cause of retrobulbar abscess in guinea pigs is bacterial infection, most commonly originating from diseased tooth roots that extend into or near the orbital space. Various bacterial species can be responsible, including Streptococcus species, Staphylococcus aureus, Pasteurella multocida, Bordetella bronchiseptica, and anaerobic bacteria that thrive in the low-oxygen environment of abscesses. Mixed infections involving multiple bacterial species are common, as the oral cavity contains diverse microbial populations that can all contribute to the infectious process. Identifying the specific organisms through culture and sensitivity testing is important for guiding antibiotic selection.

Dental disease is by far the most significant predisposing factor for retrobulbar abscess development. Guinea pigs have open-rooted teeth that grow continuously throughout life, requiring constant wear to maintain appropriate length and alignment. When dental malocclusion develops due to genetic factors, dietary inadequacy, or other causes, teeth may overgrow, develop sharp points, or grow in abnormal directions. Elongated tooth roots can penetrate toward the orbital space, and infected roots create direct pathways for bacteria to enter this normally protected area. The upper premolars and molars are most commonly involved due to their anatomical proximity to the orbit.

Traumatic causes of retrobulbar abscess are less common than dental origins but do occur. Penetrating injuries to the eye or orbit from hay, cage accessories, bites, or other sources can introduce bacteria directly into the orbital space. Even without penetration, severe facial trauma can create conditions favorable for infection development. Foreign body penetration through the conjunctiva or periorbital tissues is another potential mechanism. In some cases, no obvious source of infection can be identified, though occult dental disease often remains the most likely explanation even when not immediately apparent on initial examination.

Risk factors for retrobulbar abscess extend beyond dental disease to include various conditions that compromise health and immunity. Vitamin C deficiency is common in guinea pigs and significantly impairs immune function and wound healing, potentially allowing minor dental infections to progress to serious abscesses. Poor husbandry including inadequate diet, dirty living conditions, chronic stress, or improper housing contributes to both dental problems and reduced resistance to infection. Advanced age may increase susceptibility due to accumulated dental wear and age-related immune changes. Concurrent illness or immunosuppression from any cause allows infections to establish and progress more readily.

The pathophysiology of retrobulbar abscess involves progressive accumulation of purulent material in the enclosed orbital space. As infection becomes established, bacteria multiply and attract inflammatory cells that form pus. Unlike abscesses in loose tissues that can expand relatively freely, the orbital space is bounded by bone on multiple sides, limiting expansion and directing the pressure forward against the eye. This causes the characteristic exophthalmos or proptosis seen with retrobulbar abscess. The confined space and thick, caseous nature of guinea pig pus make spontaneous drainage unlikely without intervention. As the abscess enlarges, it compresses the eye, optic nerve, blood vessels, and muscles, causing pain and potentially permanent damage to these structures.

Early warning signs of developing retrobulbar abscess may be subtle and easily attributed to other causes. Owners might first notice mild changes in eating behavior, such as slight reluctance to chew hard foods, dropping food, or preferring softer items. There may be minor behavioral changes including slightly reduced activity, less engagement with cage mates, or increased time spent hiding. Very subtle facial asymmetry or slight puffiness around one eye might be visible to extremely attentive observers. Mild eye discharge or increased tear staining below one eye could indicate early orbital inflammation. These early signs are often only recognized in retrospect after more obvious symptoms develop.

Common symptoms of established retrobulbar abscess are dramatic and concerning. The most characteristic finding is protrusion of the affected eye, which may appear to bulge prominently forward from the socket. This exophthalmos can range from subtle forward displacement to severe protrusion where the eyelids cannot close over the globe. The eye typically appears red and irritated with conjunctival swelling and inflammation. Discharge from the affected eye is common, ranging from clear tearing to thick purulent material. Facial swelling on the affected side may be visible, sometimes extending below and behind the eye. In severe cases, the protruding eye may appear at risk of prolapsing entirely from the socket.

Behavioral changes in guinea pigs with retrobulbar abscess reflect the significant pain and illness associated with this condition. Affected animals typically show marked reduction in appetite, often refusing to eat entirely due to oral and facial pain. This anorexia is particularly dangerous in guinea pigs, whose gastrointestinal systems require continuous food intake to function properly. Lethargy is pronounced, with the guinea pig spending most of its time hiding and showing little interest in surroundings or social interaction. Normal vocalizations may decrease or stop entirely. The guinea pig may hold its head tilted away from the affected side or resist handling of its face. Weight loss occurs rapidly if appetite suppression continues.

Physical examination reveals signs extending beyond the obvious eye changes. Palpation of the face often reveals warmth and sensitivity over the affected area, with the guinea pig showing pain responses when the region is touched. Examination of the oral cavity, though limited in awake guinea pigs, may reveal signs of dental abnormalities including overgrown teeth, malocclusion, or visible periodontal disease. Body temperature may be elevated due to systemic infection. Dehydration becomes apparent through reduced skin turgor and sunken eyes (the non-affected eye may appear recessed compared to the protruding affected eye). Decreased fecal output indicates reduced food intake.

Symptom progression in untreated retrobulbar abscess follows a predictable and serious course. The eye protrusion worsens as the abscess enlarges, and pain intensifies correspondingly. Complete anorexia leads to gastrointestinal stasis, which becomes its own life-threatening complication. Systemic infection may progress to septicemia, with the guinea pig becoming increasingly weak and depressed. If the abscess ruptures, purulent material may drain through the conjunctiva, from behind the eye, or track to other locations. In severe cases, infection can spread to the brain causing meningitis or brain abscess, manifesting as neurological signs including head tilt, circling, seizures, or altered consciousness.

Emergency symptoms requiring immediate veterinary attention include any sudden, significant eye protrusion; complete refusal to eat; marked lethargy or unresponsiveness; visible pus draining from the eye area; extremely swollen, closed, or obviously painful eye; fever or abnormally low body temperature; neurological abnormalities; or signs of shock. Given that guinea pigs hide illness until severely compromised, any obvious signs of retrobulbar abscess should be treated as an emergency requiring immediate care.

Initial examination of a guinea pig with suspected retrobulbar abscess should be performed as an emergency by a veterinarian experienced in exotic animal medicine. The examination begins with rapid assessment of overall stability, as severely affected guinea pigs may require immediate supportive care before completing diagnostic workup. History from the owner includes duration of symptoms, eating behavior, any previous dental problems, diet details, and general husbandry information. Physical examination assesses vital signs, hydration status, body condition, and evidence of systemic illness. Careful examination of both eyes allows comparison, while the affected eye is evaluated for the degree of protrusion, eyelid closure capability, corneal condition, discharge characteristics, and pain responses.

Imaging studies are essential for confirming retrobulbar abscess and evaluating underlying dental disease. Skull radiographs provide valuable information, typically showing evidence of a mass behind the affected eye, and often revealing dental abnormalities such as elongated tooth roots, periapical bone changes, or obvious dental pathology. Computed tomography (CT) scanning provides far superior detail, allowing precise localization of the abscess, assessment of its extent and relationship to surrounding structures, detailed evaluation of all dental roots, and identification of bone involvement. CT is strongly recommended when available, as it provides crucial information for treatment planning. Ultrasound examination of the orbit can characterize the abscess fluid and guide aspiration if indicated.

Laboratory testing supports the diagnostic process and guides treatment. Complete blood count typically reveals elevated white blood cell count with a left shift consistent with active bacterial infection. Blood chemistry panel assesses organ function and metabolic status, helping evaluate the guinea pig's overall condition. Culture and sensitivity testing of abscess material, obtained through aspiration or surgical sampling, identifies the causative organisms and their antibiotic susceptibility patterns. This information is crucial for selecting effective antibiotic therapy, as empirical treatment may not be adequate against all potential pathogens, and some bacteria may have significant resistance patterns.

Differential diagnosis includes other conditions causing eye protrusion or facial swelling. Panophthalmitis involves infection of the eye itself rather than the space behind it, though the two conditions can coexist. Orbital tumors can cause progressive exophthalmos but typically lack the acute inflammatory signs of abscess. Orbital cellulitis involves diffuse infection of orbital tissues without the localized collection of an abscess. Zygomatic salivary gland disease can cause facial swelling that may be confused with orbital pathology. Trauma with orbital hemorrhage or swelling can cause acute eye protrusion. Careful clinical examination, imaging findings, and sometimes aspiration cytology help distinguish between these possibilities.

Emergency treatment for retrobulbar abscess must begin immediately to address both the local infection and systemic consequences. Stabilization of critically ill guinea pigs takes priority, including fluid therapy to address dehydration, which may be administered subcutaneously or intravenously depending on severity and available access. Pain management is essential, using guinea pig-safe medications such as meloxicam for anti-inflammatory pain relief and buprenorphine or tramadol for additional analgesia in severe cases. Nutritional support through syringe feeding with critical care formula must begin immediately, as gastrointestinal stasis develops rapidly in guinea pigs not eating and becomes its own life-threatening complication.

Aggressive antibiotic therapy is a cornerstone of treatment for retrobulbar abscess. Critically, antibiotic selection for guinea pigs must avoid medications that cause fatal dysbiosis by disrupting normal gut flora. Antibiotics that are dangerous or fatal for guinea pigs include penicillin, amoxicillin, ampicillin, amoxicillin-clavulanate, cephalosporins, clindamycin, lincomycin, and erythromycin. Safe and effective options include trimethoprim-sulfamethoxazole, enrofloxacin, chloramphenicol, and metronidazole when anaerobic infection is suspected. Initial treatment is typically empirical based on likely pathogens, with adjustments made according to culture and sensitivity results. Long-term antibiotic therapy, often lasting weeks to months, is typically required.

Surgical intervention is frequently necessary for successful treatment of retrobulbar abscess. The thick, caseous nature of guinea pig pus prevents adequate drainage without surgical assistance. Surgical approaches vary depending on abscess location and size, potentially including drainage through the conjunctiva, orbitotomy from behind the eye, or approaches through the oral cavity if dental extraction is also required. Complete debridement of infected and necrotic tissue improves outcomes. Dental extraction of affected teeth is often essential to address the underlying source of infection, and failure to remove infected teeth typically results in recurrence. In severe cases where the eye is irreversibly damaged or cannot be preserved, enucleation may be necessary.

Post-operative and ongoing supportive care is critical for recovery. Wound care following surgery includes maintaining drain sites if placed, monitoring incisions, and applying topical treatments as prescribed. Continued syringe feeding ensures adequate nutrition and maintains gut function, typically at rates of 80-100 ml/kg of formula daily divided into multiple feedings. Vitamin C supplementation at therapeutic doses of 50-100 mg daily supports immune function and wound healing. Subcutaneous fluids may be continued at home to maintain hydration. Pain management continues as needed, with gradual reduction as healing progresses. The guinea pig should be housed in a clean, quiet environment with soft bedding during recovery.

Long-term management following treatment for retrobulbar abscess includes ongoing attention to dental health. Regular dental examinations, often every three to four months initially, monitor for recurrence of dental problems and allow early intervention. Skull radiographs or CT imaging may be repeated periodically to assess healing and detect new dental pathology. Diet optimization emphasizing unlimited grass hay supports dental wear and gut health. Any signs of recurrence, including facial swelling, eye changes, or eating difficulties, should prompt immediate veterinary evaluation. With diligent ongoing care, many guinea pigs remain healthy after treatment for retrobulbar abscess.

Treatment decisions must honestly address the serious nature of retrobulbar abscess. Even with aggressive treatment, some guinea pigs do not survive, particularly those presenting with advanced disease or significant systemic involvement. Prognosis is improved with early intervention and worsened by delay, severe systemic illness, extensive abscess formation, or underlying conditions that complicate treatment. In cases where prognosis is poor, suffering cannot be adequately controlled, or owners cannot provide necessary intensive care, humane euthanasia may be the most appropriate choice. These discussions should be conducted compassionately while honestly presenting the realities of the condition.

Recovery timeline following treatment for retrobulbar abscess depends on the severity of disease, surgical interventions performed, and individual patient factors. Immediate improvement in comfort is often seen within 24 to 48 hours of initiating appropriate treatment as pain is controlled and the abscess is drained or surgically addressed. Return of appetite, the most important early recovery indicator, typically begins within one to three days of successful treatment initiation. Complete resolution of the abscess and healing of surgical sites generally requires four to eight weeks, though antibiotic therapy may continue for this entire period or longer. Full recovery, including resolution of any eye changes and return to normal activity, may take two to three months.

Post-treatment care during recovery requires dedicated attention from owners. Medications must be administered exactly as prescribed, including antibiotics, pain medications, and any topical eye treatments. Syringe feeding continues until the guinea pig is eating adequate amounts independently, which may take several days to a week or more. Surgical sites or drain sites require monitoring for healing progress and signs of complications such as dehiscence, excessive swelling, or purulent discharge. The guinea pig should be kept in a clean environment with soft bedding to protect healing tissues. Weight monitoring provides objective assessment of nutritional status, with daily weighing recommended during the critical early recovery period.

Prognosis for guinea pigs with retrobulbar abscess varies considerably based on multiple factors. Early detection and treatment are strongly associated with better outcomes, as delays allow abscess expansion and systemic complications to worsen. Complete surgical drainage and removal of infected teeth, when present, improves prognosis compared to medical management alone. Overall health status at presentation significantly impacts survival, with younger, previously healthy guinea pigs generally faring better than older, debilitated individuals. Owner compliance with intensive aftercare requirements affects outcomes substantially. Even with optimal treatment, recurrence rates can be significant, particularly if underlying dental disease cannot be fully addressed.

Long-term outlook for guinea pigs surviving retrobulbar abscess depends largely on dental health going forward. Those with single tooth involvement and successful extraction may do well long-term. Guinea pigs with more extensive dental disease face ongoing risk of recurrence and may require repeated interventions. Regular veterinary dental monitoring throughout life is essential. Some guinea pigs require ongoing dietary modifications if dental disease has significantly impaired their ability to chew normally. Despite these challenges, many guinea pigs recovering from retrobulbar abscess go on to live good quality lives for months to years with appropriate ongoing care.

Primary prevention of retrobulbar abscess centers on preventing and managing dental disease, the most common underlying cause. A diet based primarily on unlimited grass hay is essential for maintaining dental health, as the abrasive action of chewing hay wears down continuously growing teeth and prevents overgrowth and malocclusion. Timothy hay should be available at all times for adult guinea pigs, with other grass hays also acceptable. Fresh grass, when available, provides additional chewing exercise. Limit pelleted food to approximately one-eighth cup daily of high-quality guinea pig formula to prevent selective eating that could compromise dental wear. Avoid feeding primarily pellets, seeds, or treats that do not provide adequate dental abrasion.

Dental monitoring allows early detection and intervention before problems progress to abscess formation. Regular home observation includes watching for signs of dental problems such as difficulty chewing, food dropping, drooling, facial swelling, or changes in food preferences. Routine veterinary examinations should include oral assessment, with dental evaluations ideally every six to twelve months for healthy guinea pigs and more frequently for those with known dental issues. Professional dental care including teeth trimming when indicated helps prevent progression to more serious problems. Early treatment of malocclusion or overgrown teeth, before root involvement develops, can prevent the cascade leading to retrobulbar abscess.

Nutritional optimization supports both dental and immune health. Vitamin C supplementation is essential for guinea pigs at 25-50 mg daily for healthy adults, increased during illness or stress. Fresh vegetables high in vitamin C including bell peppers, parsley, kale, and other dark leafy greens should be offered daily. Ensure constant access to fresh, clean water. A balanced diet supports the immune system's ability to control minor infections before they can progress to serious abscesses. Avoid obesity through appropriate portion control, as excess weight contributes to various health problems.

Environmental factors also influence risk of retrobulbar abscess. Prevent injuries that could introduce infection by providing safe housing without sharp edges, monitoring cage mate interactions, and selecting appropriate bedding materials. Maintain clean living conditions to reduce bacterial burden in the guinea pig's environment. Reduce stress through appropriate housing, social groupings, and handling, as chronic stress compromises immune function. Quarantine new guinea pigs before introduction to established groups to prevent transmission of infectious agents.

Early intervention at the first sign of problems can prevent progression to retrobulbar abscess. Any facial swelling, eye changes, eating difficulties, or signs of oral discomfort should prompt immediate veterinary evaluation rather than watchful waiting. Early treatment of minor dental infections or injuries prevents them from progressing to serious abscesses. When dental problems are identified, address them promptly and completely. Recognize that guinea pigs hide illness, so even subtle signs may indicate significant underlying problems warranting investigation.

Daily management during recovery from retrobulbar abscess requires consistent, attentive care. Administer all medications at prescribed intervals, keeping a written schedule if helpful. Monitor appetite closely, documenting how much the guinea pig eats at each opportunity and whether supplemental syringe feeding remains necessary. Weigh the guinea pig daily using a gram scale to track nutritional status objectively. Observe the affected eye and surrounding area for improvement in swelling and protrusion, healing of any surgical sites, and development of any concerning signs such as increased discharge or swelling. Monitor droppings for normal size, quantity, and consistency as indicators of gastrointestinal function.

Home environment modifications support comfort and healing during recovery and afterward. Provide soft, clean bedding that will not irritate healing surgical sites or the affected eye, with paper-based products or fleece being good choices. Maintain a calm, quiet environment to reduce stress during the recovery period. Ensure food and water are easily accessible without requiring the guinea pig to navigate obstacles. Keep the cage in an area with appropriate temperature and humidity. If the guinea pig has reduced vision in the affected eye, maintain consistent cage layout to facilitate navigation. Minimize dust exposure that could irritate ocular tissues.

Quality of life assessment guides ongoing care decisions. Monitor for signs indicating acceptable quality of life including willingness to eat, normal social interaction with cage mates and owners, appropriate activity levels for the individual, and absence of obvious pain signs such as teeth grinding, hunched posture, or aggression. Conversely, watch for concerning signs including persistent appetite refusal despite treatment, isolation from cage mates, complete inactivity, obvious pain behaviors, or progressive deterioration despite appropriate care. Discuss quality of life honestly with the veterinary team and be prepared to consider humane options if suffering cannot be adequately managed.

Ongoing monitoring and veterinary care extend well beyond initial recovery. Schedule follow-up dental examinations regularly, typically every three to four months for guinea pigs with history of retrobulbar abscess, to monitor for recurrence and address any new dental issues promptly. Imaging studies may be repeated periodically to assess bone healing and detect early signs of recurrent infection. Monitor for any signs suggesting recurrence including facial swelling, eye changes, or changes in eating behavior. Report any concerns promptly rather than adopting a wait-and-see approach. Maintain excellent overall health through proper diet and husbandry to support resilience.

Caregiver support is important when managing a guinea pig through such a serious illness. Connect with guinea pig owner communities where others with experience managing similar conditions can provide practical advice and emotional support. Maintain open communication with the veterinary team, asking questions and expressing concerns as they arise. Caring for a seriously ill pet is stressful and emotionally demanding, so seek support from family, friends, or fellow guinea pig enthusiasts. Acknowledge that despite best efforts, not all guinea pigs survive retrobulbar abscess, and this does not represent failure on the owner's part. Celebrate recovery milestones and the resilience of guinea pigs who overcome this challenging condition.

All guinea pig breeds are susceptible to retrobulbar abscess since the condition is primarily secondary to dental disease, which can affect any guinea pig. However, certain factors may influence risk within different breed populations. Guinea pigs from breeding lines with high incidence of dental malocclusion may be at increased risk, as dental disease is the primary predisposing factor for retrobulbar abscess. Hereditary tendencies toward dental problems can be perpetuated through breeding, making some family lines more susceptible than others regardless of breed. Selection for certain head shapes in show breeding might theoretically influence dental anatomy, though specific breed associations with increased retrobulbar abscess risk have not been established.

Satin guinea pigs deserve special consideration in any discussion of conditions involving bone or teeth. The satin gene, responsible for the distinctive glossy coat, is associated with osteodystrophy, a condition affecting bone quality throughout the body. While direct links between satin osteodystrophy and increased retrobulbar abscess risk have not been established, any compromise to bone integrity could theoretically affect the thin orbital bones and dental structures. Owners and breeders of satin guinea pigs should be particularly attentive to dental health and monitor carefully for any signs of developing problems. Some registries and ethical breeders have moved away from breeding satin guinea pigs due to health concerns.

Breeding recommendations focus on selecting for dental health regardless of breed. Remove from breeding programs any guinea pigs with known dental disease, those requiring repeated dental interventions, or those producing offspring with dental problems. Maintain detailed health records across generations to identify lines with dental tendencies. Evaluate potential breeding animals for dental conformation before breeding, selecting those with properly aligned, normally wearing teeth. Ensure breeding animals receive appropriate diet that supports dental health. Inform buyers about any family history of dental disease so they can monitor appropriately and make informed decisions about breeding. These practices apply across all breeds and mixed heritage guinea pigs.

Commonly co-occurring conditions with retrobulbar abscess are dominated by dental disease, which is present as an underlying factor in the vast majority of cases. Dental malocclusion, molar spurs, elongated tooth roots, and tooth root abscesses frequently accompany and typically precede retrobulbar abscess development. Concurrent oral lesions such as tongue or cheek injuries from sharp dental points may be present. The systemic effects of retrobulbar abscess commonly lead to gastrointestinal stasis due to anorexia, which itself becomes a serious concurrent condition requiring treatment. Vitamin C deficiency may contribute to both dental problems and impaired healing, often requiring correction during treatment.

Conditions with similar presentation that must be differentiated from retrobulbar abscess include panophthalmitis, or infection of the eye itself, which can coexist with retrobulbar abscess or present independently with similar eye protrusion and discharge. Orbital cellulitis involves diffuse infection of orbital tissues without the localized abscess pocket. Orbital tumors can cause progressive eye protrusion but typically lack the acute inflammatory signs of infection. Zygomatic salivary gland disease causes facial swelling that may be confused with orbital pathology. Trauma causing orbital hemorrhage or swelling can produce acute eye protrusion. Careful clinical examination, imaging studies, and sometimes tissue sampling help distinguish between these possibilities, though overlapping conditions are possible.

Potential complications of retrobulbar abscess are serious and numerous. Local complications include permanent damage to the eye from compression or infection, potentially requiring enucleation even after the abscess resolves. Damage to orbital muscles may cause persistent strabismus or abnormal eye position. Extension of infection to the brain can cause meningitis or brain abscess, manifesting as neurological signs and carrying high mortality. Septicemia from bloodstream spread of bacteria causes systemic inflammatory response and potential multi-organ failure. Bone infection (osteomyelitis) of orbital or facial bones may develop and is difficult to eradicate. Gastrointestinal stasis secondary to anorexia can itself become life-threatening. Recurrence after apparently successful treatment is common if underlying dental disease persists.