Retinitis pigmentosa and inherited retinal disease awareness

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Retinitis pigmentosa commonly has a rod-cone pattern: impaired rod-mediated vision causes difficulty in darkness and adaptation to changing illumination, followed by progressive peripheral field restriction. Cone function and central vision may remain useful for a considerable period. Patients can therefore read a conventional chart yet have substantial difficulty crossing a dim hallway or locating obstacles outside the remaining field. Functional disability cannot be inferred from acuity alone.

Inherited retinal disorders vary in age at presentation, severity, inheritance and the retinal cells primarily affected. Some present in infancy with poor visual behaviour or nystagmus, while others become apparent later. A phenotype resembling retinitis pigmentosa may be isolated or form part of a multisystem disorder. The clinical task is to establish a coherent diagnosis, look for additional health implications and explain what is known without giving a falsely precise lifetime prognosis.

Genomic diagnosis can help with targeted care, relatives' assessment, reproductive counselling and consideration of a relevant therapy or study. It does not mean that every person with a molecular result has an available disease-modifying treatment. At the same time, an absence of a suitable gene therapy is not an absence of useful care: treat additional ocular disease, support remaining vision and help the person maintain independence.

Key points

Retinitis pigmentosa describes a heterogeneous group of retinal degenerations rather than one gene or one inevitable rate of sight loss.
Difficulty in dim light and peripheral field loss can precede a major fall in central chart acuity.
A negative family history does not exclude inherited disease.
Retinal imaging, fields and electrophysiology define the phenotype; genomic testing can refine diagnosis and family advice.
Support with mobility, education, work and communication should begin before severe central visual loss.
Luxturna requires confirmed biallelic RPE65-related disease, visual loss and sufficient viable retinal cells.
An uncertain genetic variant is not interchangeable with an established disease-causing result.
New symptoms require assessment for additional treatable problems such as cataract or macular oedema.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Genetically heterogeneous retinal disease

Retinitis pigmentosa can follow autosomal dominant, autosomal recessive or X-linked inheritance. Different molecular defects can produce overlapping retinal appearances and functional patterns.

Isolated or syndromic presentation

Some disorders predominantly affect the eye, while others involve additional organs. Hearing, renal, neurological and developmental findings can help identify a broader inherited syndrome.

No obvious affected relatives

A recessive condition, small pedigree, variable expression or incomplete information may obscure inheritance. Family history supports assessment but its absence does not rule out genetic retinal disease.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Rod dysfunction
In a common rod-cone pattern, rod dysfunction impairs dark adaptation and low-light vision. This explains why night-time mobility problems can develop while daytime reading remains relatively preserved.
2
Progressive field restriction
Loss of functioning peripheral retina narrows the useful visual field. A small central island can support chart recognition while making navigation and obstacle detection difficult.
3
Cone and central involvement
Cone dysfunction can later affect central acuity, contrast and colour perception. The sequence and speed differ across inherited retinal disorders, so not every patient follows an identical progression.
4
RPE65 visual-cycle dysfunction
RPE65-related disease disrupts a step in the retinal visual cycle. Gene augmentation supplies a functional coding sequence to surviving retinal pigment epithelial cells, which helps explain the requirement for viable retina.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Ask about low-light function

Explore difficulty finding a seat in a dark room, slow adaptation after entering a dim building and avoiding evening travel. These experiences may be more revealing than asking only whether distance vision is blurred.

Assess the peripheral field

Ask about bumping into doorframes, missing people approaching from the side and tripping over low obstacles. Confrontation testing may identify gross restriction, but formal field assessment better characterises the functional pattern and progression.

Take a useful family history

Record affected and apparently unaffected relatives across generations, age at symptoms, hearing problems and consanguinity where relevant. Recessive inheritance, a small family or variable expression can conceal an inherited pattern; do not require an affected parent before referring.

Seek syndromic clues

Hearing impairment, imbalance, renal problems, developmental concerns or neurological symptoms can change the investigation plan. Ask sensitively and connect relevant findings to genetics and other specialties rather than presuming the condition is confined to the retina.

Interpret appearance in context

Pigmentary change, attenuated retinal vessels and disc pallor can accompany established disease, but early disease may be less conspicuous. A normal-looking direct ophthalmoscopic examination cannot exclude retinal dysfunction in someone with a convincing history.

Red flags requiring action

Sudden new flashes, numerous floaters or a curtain of missing sight requires retinal assessment rather than routine genetic follow-up.
Pain, redness or reduced vision after gene-therapy surgery needs prompt contact with the treating retinal service.
Retinal disease with hearing, renal, neurological or developmental problems may indicate a syndrome requiring coordinated assessment beyond the eye clinic.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Visual acuity, refraction and formal fieldsFirst step
Why
Characterise remaining vision and functional limitations over time.
Interpretation and limitations
Preserved central acuity can coexist with marked peripheral restriction. Refraction and lens assessment can identify remediable contributors; field results require attention to test reliability and the method used.
02
OCT, retinal photography and fundus autofluorescence
Why
Define retinal structure and document the distribution of disease.
Interpretation and limitations
OCT can show outer-retinal loss and additional macular oedema or traction. Imaging contributes to phenotype and viable-cell assessment but cannot by itself identify the responsible gene.
03
Specialist retinal electrophysiology
Why
Assess retinal function beyond the visible anatomical appearance.
Interpretation and limitations
Full-field ERG uses responses to light under different adaptation conditions to investigate rod and cone systems. It differs from a visual evoked potential, which principally evaluates transmission along the visual pathway to the brain.
04
Genomic testing through the specialist pathway
Why
Seek a molecular diagnosis that can influence patient or family management.
Interpretation and limitations
Use the current national test-directory criteria and local genomic laboratory hub advice in England. Clinical phenotype, inheritance and variant interpretation must fit together; a variant of uncertain significance is not proof that a proposed gene caused the disease.
05
Directed assessment of extraocular features
Why
Identify health needs associated with a possible syndromic diagnosis.
Interpretation and limitations
Arrange hearing, renal or other investigations when clinical or molecular findings indicate them. A precise genomic diagnosis may uncover an important systemic surveillance requirement that was not apparent from visual symptoms alone.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Acquired retinal dysfunction

Drug toxicity, inflammatory disease and nutritional deficiency can produce retinal dysfunction or pigmentary change. Exposure history and targeted investigation help distinguish these from an inherited phenotype.

Glaucomatous field loss

Glaucoma can cause peripheral visual-field defects with preserved central acuity. Optic-disc assessment, pressure, retinal nerve-fibre imaging and field pattern help distinguish the mechanisms.

Other inherited retinal phenotypes

Cone-led or macular dystrophies may initially affect central vision, colour or light tolerance more than night-time navigation. Electrophysiology and imaging refine classification beyond a broad inherited-disease label.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Initial recognitionArrange a specialist phenotypic assessmentFirst stepA patient reports progressive low-light difficulty or peripheral visual loss consistent with inherited retinal dysfunction.

1Record the time course, monocular acuity, available field findings, family history and relevant systemic features without making an unsupported gene-level diagnosis.
2Refer to ophthalmology or an inherited retinal disease service for retinal examination, imaging and electrophysiology as appropriate.
3Separate any acute visual change from the chronic presentation and arrange urgent assessment when its symptoms require it.
4Discuss practical visual needs immediately, including lighting, falls or mobility concerns and accessible communication.

02Genomic careConnect testing with counselling and follow-upSpecialist assessment suggests a likely inherited disorder for which genomic testing could affect care.

1Explain the possible outcomes, including a diagnostic result, an uncertain finding or no identified explanation, before consent is completed.
2Select testing through the relevant commissioned pathway, guided by phenotype and genomic laboratory advice rather than a consumer test alone.
3Review the result with the clinical picture and arrange genetic counselling about relatives and reproductive options where appropriate.
4Record responsibility for communicating results, additional surveillance and later reinterpretation or reassessment when evidence changes.

03Disease-specific treatmentAssess potential RPE65 therapy eligibilityMolecular assessment identifies confirmed biallelic RPE65-related retinal dystrophy in a person with visual loss.

1Refer to the specialised treatment team to assess viable retinal cells and whether the licensed and NICE criteria are fulfilled.
2Discuss the expected functional benefit, uncertainty, surgical risks and alternatives without presenting gene augmentation as universal restoration of sight.
3Plan subretinal treatment, immunomodulatory medicines and sequential-eye timing through an experienced retinal surgical service.
4Continue postoperative surveillance and longer-term inherited disease support, including review for adverse retinal changes and other treatable ocular problems.

04Ongoing supportPreserve participation and independenceThe person is living with established inherited retinal disease whether or not a targeted treatment is available.

1Review the effect on education, work, travel, reading and daily tasks, and arrange visual rehabilitation and mobility support tailored to the remaining field.
2Assess cataract, macular complications and refractive needs rather than assuming all deterioration is irreversible inherited degeneration.
3Discuss driving and other safety-critical activities using formal visual assessment and current licensing advice where relevant.
4Offer accessible information, psychological support and consent-based involvement of family or carers while respecting the person's own decisions.

Key medicines and prescribing safety2 treatments · regimens, roles and cautions

Gene augmentation for qualifying adults and children with visual loss, confirmed biallelic RPE65 mutations and sufficient viable retinal cells.

Voretigene neparvovec, Luxturna

The specialist retinal surgeon gives a single subretinal dose of 1.5 × 10^11 vector genomes in 0.3 mL to each treated eye after product preparation. Treat the eyes on separate days at least six days apart; this is not an intravitreal anti-VEGF injection.

Use an experienced retinal surgical centre. Active ocular infection or inflammation contraindicates treatment, and systemic infection also requires postponement of the planned treatment course. Review procedure-related retinal injury, pressure elevation, cataract, infection and reported chorioretinal atrophy; discuss pregnancy and breastfeeding individually.

Perioperative systemic corticosteroid immunomodulation to reduce immune responses to the gene-transfer treatment.

Prednisone or equivalent around Luxturna

Give prednisone or an equivalent corticosteroid orally using the UK SmPC schedule: 1 mg/kg once daily, maximum 40 mg/day, for three days before each eye and four days including its procedure day. Follow with 0.5 mg/kg once daily, maximum 20 mg/day, for five days, then 0.5 mg/kg every other day, maximum 20 mg per dose, for five days.

The second-eye schedule supersedes completion of the first-eye schedule and requires one coordinated prescription. Check for infection before starting; assess glucose, blood pressure, psychiatric history and other steroid risks. Do not improvise two overlapping independent courses.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Functional field-related disability

Peripheral restriction can affect safe travel, employment and independent navigation despite useful reading acuity. Practical needs may therefore develop before severe central loss.

Additional treatable ocular disease

Cataract can occur at a younger age, and macular complications may further reduce vision. Assessing these contributors can identify useful treatment despite the underlying degeneration.

Psychological and family consequences

Uncertainty, progressive visual disability and concerns about relatives can cause distress. Genetic counselling and psychological or peer support can address different aspects of that burden.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Individualise ophthalmic follow-up to phenotype, age, progression and treatable complications, using function and imaging rather than one universal interval.
Ask about changing mobility, falls risk, hearing and participation at follow-up; apparently stable chart acuity may conceal increasing practical difficulty.
Review the interpretation of genomic results through the specialist service when new evidence or a different family finding changes the diagnostic picture.
After Luxturna, monitor the treated retina, pressure and postoperative symptoms according to the surgical plan, including the recognised risk of chorioretinal atrophy.
Ensure reproductive and family questions have a route back to genetic counselling and that results are explained in an accessible form.
After Luxturna, avoid flying or travel to high elevations until ophthalmic examination confirms that the intraocular air bubble has completely disappeared; this may take a week or longer. The treating service should also advise when swimming and strenuous activity can resume.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

The label does not determine the gene

Several genes can produce a similar rod-cone phenotype, and one gene can have variable clinical expression. Avoid inferring eligibility for a gene-specific treatment from the term retinitis pigmentosa alone.

Support can precede a molecular answer

People can benefit from visual aids, mobility training and adjustments at school or work while testing continues. Delaying these measures until a gene is identified can leave an avoidable gap in everyday functioning.

An uncertain result remains uncertain

A laboratory variant of uncertain significance needs appropriate interpretation and sometimes additional evidence. It should not independently establish predictive testing, an irreversible family decision or eligibility for a gene-specific intervention.

Genetic disease can have additional health effects

The NHS genomics education guidance illustrates how a molecular diagnosis in early retinal disease can uncover renal risk. This is a reason to connect the phenotype and result with systemic care, not to order every possible investigation for every patient.

Supplements require a clear indication

Do not recommend self-directed high-dose vitamin A as a generic cure for inherited retinal degeneration. Excess vitamin A can be harmful, including in pregnancy; treat a documented deficiency or another specific indication through an appropriate clinical plan.

Counselling includes uncertainty about time

Retinal structure, genotype and observed change can inform prognosis, but they do not yield an exact date when an individual will lose a particular ability. Explain the observed course and useful next decisions while avoiding deterministic predictions.

11Common pitfallsFrequent interpretation and management errors.

01
Excluding inherited disease because there is no known affected relative or because central acuity is still good.
02
Treating every pigmentary retinal appearance as the same genotype or the same prognosis.
03
Promising that a positive genetic test automatically makes Luxturna or another targeted therapy available.
04
Using an uncertain variant as though it were a confirmed pathogenic explanation.
05
Missing cataract, macular oedema or an acute retinal event because the patient already has an inherited diagnosis.
06
Postponing rehabilitation and practical support until all diagnostic testing has finished.