{"product_id":"raf-near-point-ruler-royal-air-force","title":"RAF Near Point Ruler — Royal Air Force Eye Muscle Exam Tool","description":"\u003cstyle\u003e.scm-pdp{font-family:'Inter','Helvetica Neue',Arial,sans-serif;color:#0d1b2a;font-size:15.5px;line-height:1.65;letter-spacing:-0.005em;max-width:880px}.scm-pdp *{box-sizing:border-box}.scm-pdp h2{font-weight:700;font-size:1.12rem;letter-spacing:-0.02em;color:#0d1b2a;margin:24px 0 10px;line-height:1.25}.scm-pdp p{margin:0 0 1em;color:#334155}.scm-pdp ul{padding-left:20px;margin:0 0 1em;color:#334155}.scm-pdp ul li{margin-bottom:5px}.scm-pdp .lead{font-size:1.02rem;color:#0d1b2a;margin-bottom:18px}.scm-pdp .badges{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0 20px}.scm-pdp .badges .b{display:inline-flex;align-items:center;gap:6px;background:#eff6ff;color:#0a4d8c;padding:5px 11px;border-radius:99px;font-size:.78rem;font-weight:600}.scm-pdp .specs{width:100%;border-collapse:collapse;font-size:.92rem;margin:14px 0;border:1px solid #e2e8f0;border-radius:8px;overflow:hidden;font-variant-numeric:tabular-nums}.scm-pdp .specs td{padding:11px 14px;border-bottom:1px solid #e2e8f0}.scm-pdp .specs tr:last-child td{border-bottom:0}.scm-pdp .specs td:first-child{color:#64748b;font-weight:500;width:42%;background:#f8fafc}.scm-pdp .faq details{border-bottom:1px solid #e2e8f0;padding:10px 0}.scm-pdp .faq summary{cursor:pointer;font-weight:600;color:#0d1b2a;padding:6px 0;font-size:.96rem}.scm-pdp .faq details p{padding:8px 0 4px;color:#334155}\u003c\/style\u003e\u003cdiv class=\"scm-pdp\"\u003e\n\u003cp class=\"lead\"\u003eThe \u003cstrong\u003eRAF Ruler\u003c\/strong\u003e (also called the RAF Rule or Royal Air Force Near Point Ruler) is a 50 cm binocular gauge for measuring near point of convergence (NPC), amplitude of accommodation, and master (dominant) eye in 1 mm increments. The RAF near point ruler was originally developed by the British Royal Air Force to screen pilot candidates for accommodative and vergence disorders; today it is standard equipment in optometry practices, orthoptic clinics, vision therapy centers, and optometry schools worldwide. Studies consistently show greater between-tester and test-retest consistency of NPC measurements with the RAF Rule than with pencil-tip or finger targets.\u003c\/p\u003e\n\u003cdiv class=\"badges\"\u003e\n\u003cspan class=\"b\"\u003e50 cm Binocular Gauge\u003c\/span\u003e\u003cspan class=\"b\"\u003e1 mm Increments\u003c\/span\u003e\u003cspan class=\"b\"\u003e4-Sided Rotating Cube\u003c\/span\u003e\u003cspan class=\"b\"\u003eIntegrated Cheek Rest\u003c\/span\u003e\u003cspan class=\"b\"\u003eRAF Original Design\u003c\/span\u003e\u003cspan class=\"b\"\u003eFree US Shipping on orders $100+\u003c\/span\u003e\n\u003c\/div\u003e\n\u003ch2\u003eWhat is a RAF ruler?\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eRAF ruler\u003c\/strong\u003e — sometimes written as \u003cstrong\u003eRAF rule\u003c\/strong\u003e, RAF near point ruler, or Royal Air Force ruler — is a hand-held optometric measurement device. It consists of a straight 50 cm ruler graduated in millimeters, a sliding fixation target holder, a four-sided rotating cube carrying different fixation targets (spot, vertical line, near-reading text of varying sizes), and a fixed cheek rest at one end. In use, the cheek rest sits against the patient's face at the outer canthus, the ruler extends horizontally toward the patient's midline, and the sliding cube is moved toward the eyes to measure convergence, or away from the eyes to measure accommodation amplitude.\u003c\/p\u003e\n\u003ch2\u003eWhat is the RAF ruler used for?\u003c\/h2\u003e\n\u003cp\u003eThe RAF near point ruler measures four clinically important vision parameters:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNear point of convergence (NPC)\u003c\/strong\u003e — the closest point at which the eyes can maintain single binocular fusion of a target as it approaches the face. Reported as break point (patient loses fusion, sees double) and recovery point (patient regains fusion). Normal NPC is typically ≤ 6 cm; values \u0026gt; 10 cm suggest convergence insufficiency.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAmplitude of accommodation\u003c\/strong\u003e — the maximum accommodative range in dioptres. Measured by push-up: the target is moved toward the patient until it first appears blurred. Amplitude = 1 ÷ (distance in meters). Age-normative values decline from ~14 D at age 20 to ~2 D at age 50.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaster (dominant) eye\u003c\/strong\u003e — determined by having the patient align the ruler ends monocularly.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePre-\/post-treatment monitoring\u003c\/strong\u003e in vision therapy for convergence insufficiency, accommodative insufficiency, and post-concussion visual dysfunction.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eHow to use the RAF near point ruler\u003c\/h2\u003e\n\u003col\u003e\n\u003cli\u003e\n\u003cstrong\u003ePosition the patient\u003c\/strong\u003e upright with head in primary gaze. Rest the cheek plate against the patient's face at the level of the outer canthus so the ruler extends horizontally toward the midline.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSelect the target\u003c\/strong\u003e by rotating the cube. Use the vertical line + central dot for convergence testing; use graded near-reading text for accommodation testing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConvergence (NPC) test:\u003c\/strong\u003e position the cube at ~30 cm from the eyes. Slowly move the cube toward the patient. Ask the patient to report doubling (\"break\") — measure and record the distance. Slowly move the cube away — ask the patient to report when the target is single again (\"recovery\"). Record both values (e.g., break 6 cm \/ recovery 8 cm).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAccommodation (push-up) test:\u003c\/strong\u003e position the near-reading target at ~40 cm. Move it toward the patient slowly. Ask the patient to report first sustained blur. Measure the distance and compute amplitude = 100 ÷ distance-in-cm dioptres.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaster eye test:\u003c\/strong\u003e Ask patient to point at the far end of the ruler with both eyes open. Close each eye alternately — the eye whose closure causes the point to jump is the non-dominant eye.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRepeat 2-3 times\u003c\/strong\u003e for reproducibility. Record all values in the patient chart.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003ch2\u003eThe 4-sided cube — what each face is for\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eFace 1 — vertical line + central dot:\u003c\/strong\u003e primary target for convergence (NPC) testing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFace 2 — near-reading text (large):\u003c\/strong\u003e for adults with reduced accommodation (presbyopia screening)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFace 3 — near-reading text (medium):\u003c\/strong\u003e for routine accommodation amplitude testing\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFace 4 — near-reading text (small):\u003c\/strong\u003e for younger patients and orthoptic training\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecification\u003c\/h2\u003e\n\u003ctable class=\"specs\"\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eLength\u003c\/td\u003e\n\u003ctd\u003e50 cm rule with sliding target holder\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMeasurement increments\u003c\/td\u003e\n\u003ctd\u003e1 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTarget\u003c\/td\u003e\n\u003ctd\u003e4-sided rotating cube with different targets per face\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePatient support\u003c\/td\u003e\n\u003ctd\u003eIntegrated cheek rest for consistent positioning\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMaterial\u003c\/td\u003e\n\u003ctd\u003eRigid plastic with printed scale\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUse\u003c\/td\u003e\n\u003ctd\u003eDiagnostic (NPC, accommodation, master eye) and therapeutic (vision therapy)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIntended user\u003c\/td\u003e\n\u003ctd\u003eOptometrists, ophthalmologists, orthoptists, vision therapy clinics, optometry schools\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\n\u003ch2\u003eClinical applications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eConvergence insufficiency diagnosis (adult and pediatric)\u003c\/li\u003e\n\u003cli\u003eAccommodative insufficiency and accommodative infacility diagnosis\u003c\/li\u003e\n\u003cli\u003ePost-concussion vision syndrome assessment\u003c\/li\u003e\n\u003cli\u003ePre- and post-vision-therapy monitoring\u003c\/li\u003e\n\u003cli\u003eMaster (dominant) eye determination for sighting-dominance tasks\u003c\/li\u003e\n\u003cli\u003eOptometry school teaching and student practice\u003c\/li\u003e\n\u003cli\u003eOrthoptic clinic outcome measurement\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\n\u003cdiv class=\"faq\"\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat does RAF ruler stand for?\u003c\/summary\u003e\u003cp\u003eRAF stands for \u003cstrong\u003eRoyal Air Force\u003c\/strong\u003e. The RAF near point ruler was originally developed by the British Royal Air Force to screen prospective pilots for convergence and accommodation disorders before military flight training. The design proved so useful that it was adopted worldwide as a standard optometric tool and is still known as the RAF Ruler or RAF Rule.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat is a normal NPC (near point of convergence) result on the RAF ruler?\u003c\/summary\u003e\u003cp\u003eA normal NPC break value on the RAF ruler is typically ≤ 6 cm and a normal recovery value is ≤ 8 cm. Values greater than 10 cm break are suggestive of \u003cstrong\u003econvergence insufficiency\u003c\/strong\u003e, particularly if accompanied by symptoms of asthenopia, diplopia during near work, or headaches with reading.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow is the RAF ruler used to measure accommodation?\u003c\/summary\u003e\u003cp\u003ePlace the ruler with cheek rest against the patient's face at the outer canthus. Position the near-reading target at ~40 cm. Ask the patient to look at the smallest print they can read clearly, then move the target slowly toward the patient. When the print first goes sustainably blurred, measure the distance. Accommodative amplitude in dioptres = 100 ÷ distance-in-centimeters.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat's the difference between RAF ruler and Prince rule?\u003c\/summary\u003e\u003cp\u003eBoth are near-point-of-convergence rulers. The Prince rule (also called the RAF-Prince rule) adds a printed near-reading card with graded print sizes on the sliding target, whereas the classic RAF ruler uses a 4-sided rotating cube with targets on each face. Clinically both are used interchangeably; the RAF ruler is more common in the UK and Commonwealth, the Prince rule more common in North American optometry schools.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eIs the RAF ruler suitable for optometry school teaching?\u003c\/summary\u003e\u003cp\u003eYes. The RAF near point ruler is standard first-year equipment in most optometry and orthoptic training programs internationally. For teaching-clinic bulk orders (10+ units) contact \u003ca href=\"mailto:sales@scimedstore.com\"\u003esales@scimedstore.com\u003c\/a\u003e for institutional pricing.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eWhat ages can the RAF ruler be used on?\u003c\/summary\u003e\u003cp\u003eThe RAF ruler is suitable for cooperative patients from approximately age 4 upward. For younger children or non-verbal patients, objective NPC assessment methods (observation of eye movements, cover testing) are typically substituted for the subjective push-up test.\u003c\/p\u003e\u003c\/details\u003e\n\u003cdetails\u003e\u003csummary\u003eHow is the RAF ruler shipped from SciMed?\u003c\/summary\u003e\u003cp\u003eDirect from our San Jose, California distribution center. Free US ground shipping on orders $100+ with same-day dispatch on orders before 2 PM PT. International shipping available; contact \u003ca href=\"mailto:sales@scimedstore.com\"\u003esales@scimedstore.com\u003c\/a\u003e for landed-cost quote.\u003c\/p\u003e\u003c\/details\u003e\n\u003c\/div\u003e\n\u003ch2\u003eAlso known as\u003c\/h2\u003e\n\u003cp\u003eRAF rule · RAF near point ruler · Royal Air Force ruler · Royal Air Force near point ruler · RAF NPC ruler · near point ruler · accommodation ruler\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003eFor optometry-school and orthoptic-clinic bulk orders (10+ units) contact \u003ca href=\"mailto:sales@scimedstore.com\"\u003esales@scimedstore.com\u003c\/a\u003e or \u003ca href=\"tel:+16692659353\"\u003e(669) 265-9353\u003c\/a\u003e.\u003c\/em\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\",\"@type\":\"Product\",\"name\":\"RAF Ruler — Royal Air Force Near Point Ruler\",\"alternateName\":[\"RAF rule\",\"RAF near point ruler\",\"Royal Air Force ruler\",\"Royal Air Force near point ruler\",\"RAF NPC ruler\"],\"description\":\"50 cm binocular gauge for measuring near point of convergence (NPC), amplitude of accommodation, and master eye in 1 mm increments. Four-sided rotating cube with fixation targets and integrated cheek rest.\",\"category\":\"Optometry diagnostic instrument\"}\u003c\/script\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[{\"@type\":\"Question\",\"name\":\"What does RAF ruler stand for?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"RAF stands for Royal Air Force. The RAF near point ruler was originally developed by the British Royal Air Force to screen prospective pilots for convergence and accommodation disorders before military flight training.\"}},{\"@type\":\"Question\",\"name\":\"What is a normal NPC (near point of convergence) result on the RAF ruler?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"A normal NPC break value on the RAF ruler is typically ≤ 6 cm and a normal recovery value is ≤ 8 cm. Values greater than 10 cm break are suggestive of convergence insufficiency.\"}},{\"@type\":\"Question\",\"name\":\"How is the RAF ruler used to measure accommodation?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Place the ruler with cheek rest against the patient's face. Position the near-reading target at 40 cm. Ask the patient to look at the smallest print they can read clearly, then move the target slowly toward the patient until first sustained blur. Amplitude in dioptres = 100 ÷ distance in cm.\"}},{\"@type\":\"Question\",\"name\":\"What's the difference between RAF ruler and Prince rule?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\n\"text\":\"Both are near-point-of-convergence rulers. The Prince rule adds a printed near-reading card whereas the classic RAF ruler uses a 4-sided rotating cube. Clinically both are used interchangeably; RAF is more common in UK\/Commonwealth, Prince is more common in North American optometry schools.\"}},{\"@type\":\"Question\",\"name\":\"Is the RAF ruler suitable for optometry school teaching?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Yes. The RAF near point ruler is standard first-year equipment in most optometry and orthoptic training programs internationally. Teaching-clinic bulk orders (10+ units) receive institutional pricing.\"}},{\"@type\":\"Question\",\"name\":\"What ages can the RAF ruler be used on?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The RAF ruler is suitable for cooperative patients from approximately age 4 upward. For younger children objective NPC assessment methods are typically substituted for the subjective push-up test.\"}}]}\u003c\/script\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\":\"https:\/\/schema.org\",\"@type\":\"BreadcrumbList\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/scimedstore.com\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Ophthalmology\",\"item\":\"https:\/\/scimedstore.com\/collections\/ophthalmology-products\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"RAF Ruler — Near Point Ruler\",\"item\":\"https:\/\/scimedstore.com\/products\/royal-air-force-ruleraf-near-point-ruler\"}]}\u003c\/script\u003e\n\u003cdiv class=\"scimed-manual\" style=\"margin:24px 0;padding:14px 16px;border:1px solid #1f7a8c;border-radius:8px;background:#eef4f7\"\u003e\n\u003ch3 style=\"margin:0 0 6px\"\u003eUser Manual (PDF)\u003c\/h3\u003e\n\u003cp style=\"margin:0 0 6px\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0578\/9319\/1739\/files\/SciMed-raf-near-point-ruler-Instructions-for-Use.pdf\" target=\"_blank\" rel=\"noopener\" download\u003e\u003cstrong\u003eDownload the Instructions for Use (PDF)\u003c\/strong\u003e\u003c\/a\u003e\u003c\/p\u003e\n\u003cp style=\"margin:0\"\u003eBrowse all manuals by category at \u003ca href=\"\/en-fr\/pages\/user-manuals\"\u003escimedstore.com\/pages\/user-manuals\u003c\/a\u003e. Need a digital or printed copy, or have a question? Email \u003ca href=\"mailto:sales@scimedstore.com\"\u003esales@scimedstore.com\u003c\/a\u003e.\u003c\/p\u003e\n\u003c\/div\u003e","brand":"SciMed","offers":[{"title":"Default Title","offer_id":40678801440827,"sku":"AY1EV211","price":399.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0578\/9319\/1739\/products\/s-l1600_43.jpg?v=1660555868","url":"https:\/\/scimedstore.com\/en-fr\/products\/raf-near-point-ruler-royal-air-force","provider":"SciMed","version":"1.0","type":"link"}