«“√ “√®—°…ÿ∏√√¡»“ μ√ å ªï∑’Ë 3 ©∫—∫∑’Ë 2 °√°Æ“§¡-∏—𫓧¡ 2551 55

Keratoconus

Õ“®“√¬å ·æ∑¬åÀ≠‘ß∑—»π’¬å »‘√‘°ÿ≈ ¿“§«‘™“®—°…ÿ«‘∑¬“ §≥–·æ∑¬»“ μ√å ¡À“«‘∑¬“≈—¬∏√√¡»“ μ√å

Keratoconus ‡ªìπ¿“«– bilateral noninflammatory corneal ectasia ‡°‘¥®“° corneal stroma ¡’°“√ ∫“ß≈ß ∑”„À⇰‘¥°“√‚ªÉߢÕß°√–®°μ“‡ªìπ√Ÿª‚§π„π∫√‘‡«≥ central À√◊Õ paracentral ¢Õß àߺ≈∑”„Àâ ‡°‘¥¿“«– “¬μ“º‘¥ª°μ‘ ‡™àπ “¬μ“ —Èπ () À√◊Õ “¬μ“‡Õ’¬ß·∫∫ irregular ´÷Ëß¡’º≈∑”„Àâ §ÿ≥¿“æ°“√¡Õ߇ÀÁπ≈¥≈߉¥âμ—Èß·μà√–¥—∫‡≈Á°πâÕ¬®π∂÷ß¡“°

Epidemiology ¿“«–π’È‚¥¬ à«π„À≠à‡ªìπ isolated condition “¡“√∂æ∫‰¥â„π∑ÿ°‡™◊ÈÕ™“μ‘ æ∫„π‡æ»™“¬ Õ¬à“߉√°Áμ“¡¡’√“¬ß“π°“√æ∫√à«¡°—∫§«“¡º‘¥ª°μ‘ ‰¥â‡∑à“°—∫‡æ»À≠‘ß √“¬ß“πÕÿ∫—μ‘°“√≥å°“√‡°‘¥‚√§¡’ Õ◊ËπÊ ¥—ßμ“√“ß∑’Ë 1 ¿“«–‡°’ˬ«¢âÕß∑’Ëæ∫‰¥â∫àÕ¬ ‡™àπ À≈“°À≈“¬ ‚¥¬‡©≈¬æ∫ª√–¡“≥’Ë 1 μÕà 2,000 §«“¡ Downûs syndrome, Leber congenital amaurosis ·μ°μà“ß„π incidence ∑’Ë√“¬ß“πÕ“®‡π◊ËÕß®“° „™â‡°≥±å„π°“√«‘π‘®©—¬∑’Ë·μ°μà“ß°—π

μ“√“ß∑’Ë 1 Systemic and ocular diseases reported in association with keratoconus

Multisystem Disorders Ocular Disorders (Non-corneal) Alagilleûs syndrome Albers - Schonberg disease Anetoderma and bilateral subcapsular Angleman syndrome Ankyloblepharon Apertûs syndrome Bilateral macular coloboma Autographism Blue Anetoderma Congenital cataracts Bardet-Biedl syndrome Ectodermal and mesodermal anomalies Crouzonûs syndrome Floppy syndrome Downûs syndrome Gyrate atrophy Ehlers-Danlos syndrome Iridoschisis Goltz-Gorlin syndrome Leber congenital amaurosis Hyperornithemia Persistent pupillary membrane Icthyosis Posterior lenticonus 56 ∑—»π’¬å »‘√‘°ÿ≈

Kurz syndrome pigmentosa Laurence-Moon-Bardet-Biedl syndrome Retinal disinsertion syndrome Marfanûs syndrome Retrolental fibroplasia Mulvihil-Smith syndrome Vernal Nail patella syndrome Corneal Disorders Neurocutaneous angiomatosis Atopic Neurofibromatosis Axenfeldûs anomaly Noonanûs syndrome Avellinoûs dystrophy Osteogenesis imperfecta Chandlerûs syndrome Oculodentodigital syndrome Corneal amyloidosis Pseudoxanthoma elasticum Deep filiform Riegerûs syndrome Essential atrophy Rothmundûs syndrome Fleck corneal dystrophy Touretteûs disease Fuchs corneal dystrophy Turnerûs syndrome Iridocorneal dysgenesis Xeroderma pigmentosa Lattice dystrophy Other Systemic Disorders Microcornea Congenital hip dysplasia Pellucid marginal degeneration False chordae tendinae of left ventricle Posterior polymorphous dystrophy Joint hypermobility Terriens marginal degeneration Mitral valve prolapse Measles Thalesselis syndrome

Clinical features ¿“«–°√–®°μ“‚ªÉßπ’È¡—°®–‡ªìπ∑—Èß 2 μ“ ·μà lamp ‰¡àæ∫§«“¡º‘¥ª°μ‘∑’Ë°√–®°μ“ °√≥’°“√¥Ÿ¥â«¬ Õ“®®–‡°‘¥¢÷Èπ„πμ“¢â“ß„¥¢â“ßÀπ÷Ëß°àÕπ ¡’≈—°…≥–‡ªìπ keratometry mires Õ“®æ∫¡’ slight distortion À√◊Õ progressive disorder à«π¡“°‡°‘¥„π™à«ß«—¬√ÿàπ·≈– steepening ∫√‘‡«≥ central À√◊Õ inferior ‡¡◊ËÕ ‡ªìπ¡“°¢÷Èπ‡√◊ËÕ¬Ê ®π§ß∑’Ë∑’ËÕ“¬ÿ 30-40 ªï Õ“°“√ ∑”°“√μ√«®¥â«¬ retinoscope ®–æ∫≈—°…≥–‡ªìπ ·≈–Õ“°“√· ¥ß¡’‰¥âÀ≈“°À≈“¬¢÷Èπ°—∫√–¬–¢Õß‚√§ scissoring reflex ·≈–∂â“∑”°“√¢¬“¬¡à“πμ“·≈â« „π√–¬–·√°ºŸâªÉ«¬Õ“®‰¡à¡’Õ“°“√ ¡’‡æ’¬ß “¬μ“∑’Ë μ√«®¥Ÿ¥â«¬ retinoscope À√◊Õ ophthalmoscope · ß º‘¥ª°μ‘ ‡¡◊ËÕ∑”°“√«—¥ “¬μ“‰¡à “¡“√∂∑’Ë®–«—¥ best –∑âÕπ∑’Ëæ∫®–¡’≈—°…≥–‡ªìπ oil droplet reflex corrected visual acuity ‰¥â 20/20 μ√«®¥â«¬ slit- (çCharleuxé sign) (√Ÿª∑’Ë 1) ´÷Ëߙ૬„π°“√«‘π‘®©—¬ Keratoconus 57

√Ÿª∑’Ë 1 Oil droplet reflex ∑’Ëæ∫‰¥â„π‚√§ keratoconus

„π°√≥’∑’Ë ß —¬‚√§π’ȉ¥â °√≥’∑’Ë ß —¬¿“«– keratoco- °√≥∑’ ‡ª’Ë πì moderate to advanced case Õ“® nus √–¬–‡√‘Ë¡·√° °“√ àßμ√«®¥â«¬‡§√◊ËÕß¡◊Õ corneal μ√«®æ∫ signs Õ◊ËπÊ ¢÷Èπ°—∫§«“¡√ÿπ·√ߢÕß‚√§ topography ®–™à«¬¬◊π¬—π°“√«‘π‘®©—¬‰¥â Õ“°“√· ¥ßμ“ßÊà ∑æ∫‰¥’Ë „π‚√§â keratoconus ¥ß· ¥ß— „πμ“√“ß∑’Ë 2

μ“√“ß∑’Ë 2 Signs μà“ß Ê∑’Ëæ∫‰¥â„π‚√§ keratoconus

External signs Munsonûs sign Rizzuti phenomenon Slit-lamp findings Stromal thinning Posterior stress lines (Vogt striae) Iron ring (Fleischer ring) Scarring - epithelial or subepithelial Retroillumination signs Scissoring on retinoscopy Oil droplet sign çCharleuxé Photokeratoscopy signs Compression of mires inferotemporally (çegg-shapedé mires) Compression of mires inferiorly or centrally Videokeratography signs (√Ÿª∑’Ë 2) Localized increased surface power Inferior superior dioptric asymmetry Relative skewing of the steepest radial axes above and below the horizontal meridian 58 ∑—»π’¬å »‘√‘°ÿ≈

√Ÿª∑’Ë 2 Videokeratograph ®“° orbscan „πºªŸâ «¬É √Ÿª∑’Ë 3 Munsonûs sign „π keratoconus ‡ª≈◊Õ° keratoconus μ“≈à“ß¡’≈—°…≥–‡ªìπ√Ÿªμ—« V ‡¡◊ËÕºŸâªÉ«¬ ¡Õß≈ß≈à“ß external signs ∑æ∫‰¥’Ë ·°â à Munsonûs sign §Õ◊ ‡¡◊ËÕ„À⺟âªÉ«¬¡Õß≈ß≈à“ß°√–®°μ“∑’Ë‚ªÉß®–∑”„Àâ ‡ª≈Õ°μ“≈◊ “ß¡à ≈’ °…≥–‡ª— π√ì ªμŸ «— V (√ª∑Ÿ ’Ë 3) Rizzutiûs sign μ√«®‰¥‚¥¬∑”°“√ â Õ߉øà ∫√‡«≥‘ temporal ¢Õß °√–®°μ“ ®–‡°¥≈”· ß∑‘ ‚ø°’Ë √«¡°— π‡ª— π¬Õ¥·À≈¡ì (conical reflection) ∑’Ë¥â“π nasal ¢Õß°√–®°μ“ (√Ÿª∑’Ë 4) ‡¡◊ËÕ∑”°“√μ√«®¥â«¬ slit lamp æ∫¡’ stro- mal thinning ∫√‘‡«≥ inferior À√◊Õ inferotemporal, æ∫¡’ conical protrusion, ¡’ iron line ∫√‘‡«≥√Õ∫ ‚§π‡√¬°«’ “à çFleischerûs ringé, Õ“®æ∫¡ ’ vertical line √Ÿª∑’Ë 4 Rizzutiûs sign æ∫ conical reflection „π™—Èπ deep stroma ¢π“π°—∫ axis ¢Õß‚§π‡√’¬°«à“ μ”·Àπàß nasal cornea ‡¡◊ËÕ àÕ߉ø®“° çVogt striaeé ´÷Ëß vertical line π’È “¡“√∂À“¬‰ª‰¥â ∑“ߥâ“π temporal ‡¡◊ËÕÕÕ°·√ß°¥∑’Ë°√–®°μ“ Õ“°“√· ¥ßÕ◊ËπÊ ∑’ËÕ“® μ√«®æ∫‰¥â ‡™àπ anterior stromal scar, enlarged „πºŸâªÉ«¬∑’ˇªìπ advanced disease ∫“ߧ√—Èß corneal nerves, subepithelial fibrillary line Õ“®¡“¥â«¬Õ“°“√ª«¥μ“ μ“¡—«≈ß©—∫æ≈—π ´÷Ë߇°‘¥ ®“°°“√∑’Ë¡’°“√©’°¢“¥¢Õß Descemetûs membrane ∑”„À⇰‘¥ stromal edema μ√«®μ“æ∫«à“¡’ conjunc- tival injection, diffuse stromal opacity ´÷Ë߇√’¬° ¿“«–π’È«à“ çhydropsé (√Ÿª∑’Ë 5) °√–®°μ“Õ“®∫«¡ Õ¬Ÿàπ“π‡ªìπ —ª¥“Àå∂÷߇ªìπ‡¥◊Õπ‰¥â À≈—ß®“°π—Èπ °√–®°μ“®–§Õ¬à ʬ∫∫«¡ÿ ·≈–‡°¥‡ª‘ πì corneal scar μ“¡¡“‰¥â Keratoconus 59

iron „π™—Èπ basal layers ¢Õß corneal epithelium „π ™—Èπ stroma ®–æ∫«à“¡’ loss of arrangement of fibrils „π∫√‘‡«≥™—Èπ anterior stroma, ®”π«π collagen lamellae ≈¥≈ß·≈–æ∫∑—Èß normal ·≈– degenerating fibroblasts ‚¥¬ª°μ‘™—Èπ Descemetûs membrane ¡—°®–ª°μ‘¬°‡«âπ°√≥’∑’Ë¡’ acute hydrops ®–æ∫¡’ break „π™—Èπ Descemetûs membrane ‰¥â ‚¥¬∑—Ë«‰ª ™—Èπ endothelium ®–ª°μ‘

√Ÿª∑’Ë 5 Acute hydrops ∑”„À⇰‘¥ central corneal Differential diagnosis edema Keratoconus ®—¥Õ¬Ÿà„π°≈ÿà¡ corneal ectatic disorders ´÷Ëß®”‡ªìπμâÕß«‘π‘®©—¬·¬°‚√§®“° ectatic Histopathology disorders Õ◊ËπÊ ‰¥â·°à Pellucid marginal degenera- Classic histopathology features ∑’Ëæ∫„π tion ·≈– ≈—°…≥–¢Õß·μà≈–‚√§ keratoconus ‰¥â·°à thinning ¢Õß corneal stroma, ¥—ß· ¥ß„πμ“√“ß∑’Ë 3 breaks in Bowmanûs layer ·≈–¡’ deposition ¢Õß

μ“√“ß∑’Ë 3 Noninflammatomy ectatic disorders typical clinical appearance

Pellucid marginal Keratoconus Keratoglobus degeneration Frequency most common less common rare Laterality usually bilateral bilateral bilateral Age at onset puberty age 20-40 years usually at birth Thinning inferior paracentral inferior band of 1-2 mm wide greatest in periphery Protrusion thinnest at apex superior to band of thinning generalized Iron line Fleischer ring sometimes none Scarring common only after hydrop mild Striae common Sometimes sometimes 60 ∑—»π’¬å »‘√‘°ÿ≈

1) Pellucid marginal degeneration soft toric ¬—ߧ߄Àâº≈¥’ ‡¡◊ËÕ‚√§‡ªìπ¡“°¢÷ÈπÕ“®‡°‘¥ æ∫„π™à«ßÕ“¬ÿ 20-40 ªï ‡æ»™“¬‡∑à“ Ê °—∫‡æ»À≠‘ß irregular astigmatism ∑∑”„À’Ë μâ Õ߇ª≈â ¬π¡“·°’Ë ‰¢¥â «¬â °√–®°μ“¡’·∂∫∫“ß∫√‘‡«≥ inferior ·≈–¡’°“√‚ªÉß rigid gas permeable lenses ·∑π ´÷Ëß°“√‡≈◊Õ° ¬◊Ëπ¢Õß°√–®°μ“ (protrusion) ∫√‘‡«≥‡Àπ◊Õμ”·Àπàß fitting ∑‡À¡“– ¡®–™’Ë «¬≈¥°“√‡°à ¥‘ complication ®“° ∑’ˇªìπ·∂∫∫“ß ´÷Ëßμà“ß®“° keratoconus ∑’Ëμ”·Àπàß §Õπ·∑§‡≈π 剥⠇™àπ apical scar, corneal abrasion, °√–®°μ“∑’Ë∫“ß®–‡ªìπμ”·Àπàß apex ¢Õß protrusion neovascularization, discomfort ∫“ß√“¬Õ“®·¬°‰¥â¬“°®“°¿“«– keratoconus °“√ μ√«®¥â«¬ videokeratography æ∫ inferior steep- 2. Excimer laser phototherapeutic ening ≈—°…≥–‡ªìπ classical çbutterflyé appear- keratectomy (PTK) ance ·≈–‡ªìπ against the rule astigmatism „π∫“ß°√≥’Õ“®æ∫ raised, nodular, super- 2) Keratoglobus æ∫πâÕ¬ ¡—°‡ªìπμ—Èß·μà ficial scars (proud nebulae) ∑”„À⇰‘¥ªí≠À“„ à ‡°‘¥ ‡ªìπ bilateral disease ‚¥¬æ∫°√–®°μ“∫“ß≈ß §Õπ·∑§‡≈π å‰¡à‰¥â ≈—°…≥–∑’Ëæ∫¡—°‡ªìπ°âÕππŸπ ∑—ÈßÀ¡¥ ¡—°∫“ß∑’Ë ÿ¥„πμ”·Àπàß„°≈âÊ limbus ∑”„Àâ ‡¥’ˬ«¢π“¥ 1-2 ¡‘≈≈‘‡¡μ√ ∫√‘‡«≥ apex ¢Õß‚§π °√–®°μ“ªÕßÕÕ°‡ªÉ πì globular shape ·≈–æ∫¡ ’ very §≈⓬°—∫≈—°…≥– Salzmannûs degeneration ‡¡◊ËÕ„ à deep anterior chamber ∂â“¡’ trauma Õ“®‡°‘¥ §Õπ·∑§‡≈π åÕ“®∑”„Àâ√Ÿâ ÷°‰¡à ∫“¬μ“ ¡’ punctate perforate ‰¥âßà“¬ „π°√≥’ advanced keratoconus keratopathy À√◊Õ abrasion ‰¥â °√≥’π’È “¡“√∂‡≈◊Õ° °√–®°μ“Õ“®¡’°“√∫“ß≈߇°◊Õ∫∑—ÈßÀ¡¥ ·≈–¡’ √—°…“¥â«¬ surgical superficial keratectomy À√◊Õ ≈—°…≥–‡ªìπ globular shape ∑”„Àâ§≈⓬°—∫¿“«– excimer laser phototherapeutic keratectomy Õ“® keratoglobus ‰¥â Õ¬à“߉√°Áμ“¡ “¡“√∂·¬°§«“¡ ™à«¬„Àâ “¡“√∂°≈—∫‰ª„ à§Õπ·∑§‡≈π 剥⠷≈–™à«¬ ·μ°μà“߉¥â®“°°“√ —߇°μ¥Ÿ„π∫√‘‡«≥ superior delay °“√∑” surgical intervention Õ◊ËπÊ cornea ´ß¡÷Ë °®–¬— ß¡— ∫√’ ‡«≥∑‘ §«“¡À𓪰μ’Ë ‰¥‘ „π°√≥â ’ ”À√—∫°“√∑” Lasik ‡ªìπ contraindication ∑’ˇªìπ advanced keratoconus ”À√—∫‚√§ keratoconus

Management 3. Corneal transplantation °“√√—°…“¿“«– keratoconus ¢÷Èπ°—∫√–¬– °√≥’∑’Ë‚√§¡’§«“¡√ÿπ·√ß¡“°¢÷Èπ°“√„ à ¢Õß‚√§ ¡’À≈“¬«‘∏’„π°“√√—°…“ ”À√—∫°“√√—°…“„π §Õπ·∑§‡≈π åÕ“®‰¡à‰¥âº≈°“√¡Õ߇ÀÁπ∑’Ë¥’ °“√ ™à«ß acute hydrops °“√„Àâ cycloplegics, steroid, ºà“μ—¥‡ª≈’ˬπ°√–®°μ“¥â«¬«‘∏’ penetrating kerato- NSAIDS, ·≈– 5% sodium chloride ™à«¬„ÀâÕ“°“√¥’ plasty ‡ªìπ°“√ºà“μ—¥∑’Ë„Àâº≈ ”‡√Á®„π°“√√—°…“∑’Ë¥’ ¢÷Èπ‰¥â ¢âÕ∫àß™’È„π°“√ºà“μ—¥‡ª≈’ˬπ°√–®°μ“‰¥â·°à ë Contact lenses intolerance 1. Contact lenses ë °“√¡Õ߇ÀÁπ‰¡à™—¥·¡â«à“®–·°â‰¢¥â«¬ „π√–¬–‡√‘Ë¡μâπ°“√„ à·«àπÕ“®™à«¬„Àâ°“√ §Õπ·∑§‡≈π å·≈â« ¡Õ߇ÀÁπ¥’‰¥â„π√–¥—∫Àπ÷Ëß Õ¬à“߉√°Áμ“¡°“√„ à ë¡’ corneal scar ∑’Ë¡’º≈∫—ß°“√¡Õ߇ÀÁπ §Õπ·∑§‡≈π å„Àâº≈°“√¡Õ߇ÀÁπ∑’Ë¥’°«à“ „π√–¬–·√° Keratoconus 61

¿“«–·∑√°´âÕπÀ≈—ß°“√ºà“μ—¥∑’Ëæ∫‰¥â ‡™àπ «ß°≈¡ ‡¢â“‰ª„π™—Èπ stroma ∑’˧«“¡≈÷°ª√–¡“≥ 2/3 postoperative astigmatism, graft rejection, fixed „π∫√‘‡«≥ peripheral cornea „π≈—°…≥– circum- dilated (Urrets-Zavalia syndrome), recurrence ferential pattern ´÷Ëß¡’º≈∑”„À⇰‘¥°“√ flattening and keratoconus ”À√—∫ success rate ¢Õß°“√ repositioning cornea ‰¥â (√Ÿª∑’Ë 6) àߺ≈„Àâ¡’ “¬μ“ ºà“μ—¥‡ª≈’ˬπ°√–®°μ“„π°√≥’ keratoconus Ÿß¡“° —Èπ·≈–‡Õ’¬ßπâÕ¬≈߉¥â °«à“ 90% ´÷Ëß„Àâº≈¥’·≈–‚Õ°“ °“√‡°‘¥ graft rejec- ¢Õ∫â ß™à „π°“√√’È —°…“‰¥·°â à tion „π keratoconus æ∫‰¥âπâÕ¬‡¡◊ËÕ‡∑’¬∫°—∫ ë Õ“¬ÿ 21 ªï¢÷Èπ‰ª °“√ºà“μ—¥‡ª≈’ˬπ°√–®°μ“„π°√≥’‚√§Õ◊ËπÊ ë Clear central cornea ë Cornea ∫√‘‡«≥∑’Ë®–∑”°“√ºà“μ—¥μâÕß¡’ 4. Intrastromal corneal ring (INTACS®) §«“¡Àπ“¢Õß°√–®°μ“Õ¬à“ßπâÕ¬ 450 microns ‡ªìπÕ’°«‘∏’Àπ÷Ëß„π°“√√—°…“ ´÷Ë߉¥â√—∫ FDA ë‰¡à “¡“√∂·°â‰¢„Àâ¡Õ߇ÀÁπ¥’¢÷Èπ‰¥â¥â«¬ approve „πªï 2004 ”À√—∫„™â„π°“√√—°…“ kerato- «‘∏’Õ◊ËπÊ πÕ°‡Àπ◊Õ®“°°“√∑” corneal transplan- conus ∑”‰¥â‚¥¬°“√„ à«— ¥ÿ∑’Ë∑”¡“®“° polymethyl- tation ‡∑à“π—Èπ methacrylate (PMMA) ∑’Ë¡’≈—°…≥–‚§â߇ªìπ∑√ߧ√÷Ëß

√Ÿª∑’Ë 6 Intrastromal corneal ring

¿“«–·∑√°´âÕπ∑’Ëæ∫‰¥â®“°°“√„ à ‡™àπ 5. Corneal collagen crosslinking anterior chamber perforation, dense corneal in- ‡ªìπ new modality „π°“√√—°…“ keratoco- filtration, ring exposure ´÷Ëß„π¢—ÈπμÕπ°“√∑” chan- nus ¡™’ Õ‡√◊Ë ¬°‰¥’ À≈“¬·∫∫â ‡™πà CXL, CCL À√Õ◊ C3- nel ‡æ◊ËÕ∑’Ë®–„ à ring ‡¢â“‰ª∑”‰¥â‚¥¬„™â mechanical R ‚¥¬„™âÀ≈—°°“√ photo-polymerization ∑”„À⇰‘¥ spreader ´÷ËßμâÕßÕ“»—¬∑—°…–·≈–§«“¡™”π“≠„π cross-links „π connective tissue àߺ≈„Àâ °“√„ à „πªí®®ÿ∫—π¡’°“√æ—≤π“π” femtosecond laser °√–®°μ“¡§«“¡·¢’ ß·√ß¡“°¢Á π÷È ∑”‰¥‚¥¬À¬Õ¥ “√â ¡“™à«¬„π°“√∑” channel ∑”„Àâ¡’§«“¡ –¥«°·≈– riboflavin (vitamin B2) ∑’Ëμ“ À≈—ß®“°πÈ—π∑”°“√ ‰¥â√–¥—∫§«“¡≈÷°∑’Ë·¡àπ¬”¡“°¢÷Èπ °√–μÿâπ¥â«¬°“√©“¬√—ß ’ UV-A light ∑’Ë√–¥—∫ 3 mw/ 62 ∑—»π’¬å »‘√‘°ÿ≈ cm2 ‡ªìπ‡«≈“ 30 π“∑’ “√ riboflavin ´÷Ë߇ªìπ “√ ¬ß§ß¡— ¢’ Õ®”°â ¥∂— ߧ«“¡ª≈Õ¥¿÷ ¬®“°— UV-A μÕà en- photosensitizer ®–∑”„À⇰‘¥ singlet oxygen ·≈– dothelial cell ·≈– ¥—ßπ—Èπ„πªí®®ÿ∫—π¡’°“√ superoxide free radicals ∑”„À⇰‘¥ cross-linking æ‘®“√≥“π”¡“„™â„π°√≥’∑’Ë¡’°“√ progression ¢Õß √–À«à“ß corneal collagen fiber ™à«¬‡æ‘Ë¡§«“¡·¢Áß·√ß ‚√§·≈–μÕß¡â §«“¡Àπ“°√–®°μ“‡∑’ “°à ∫À√— Õ¡“°°«◊ “à ¢Õß°√–®°μ“ (√Ÿª∑’Ë 7) ≈¥‚Õ°“ ‡°‘¥ progression 400 microns ·≈–¬—ߧßμâÕß¡’°“√»÷°…“∂÷ߺ≈„π ¢Õß‚√§‰¥â „π∫“ß√“¬ “¡“√∂‡æ‘Ë¡√–¥—∫°“√ √–¬–¬“«μÕ‰ªà ¡Õ߇ÀÁπ·≈–≈¥§à“ myopia ·≈– astigmatism ‰¥â ´÷Ëß

√Ÿª∑’Ë 7 · ¥ß≈—°…≥– cross linking √–À«à“ß collagen fiber ∑’ˇæ‘Ë¡¡“°¢÷Èπ¥â«¬À≈—°°“√ photo-polymerization

References 4. Rabinowitz YS. Intacs for keratoconus. 1. Rabinowitz YS. Keratoconus. Surv Ophthalmol Curr Opin Ophthalmol 2007; 18:279-283. 1998; 42:297-319. 5. Ertan A, Kamburoglu G, Bahadir M. Intacs 2. Leibowitz HM, Sergio Morello JR. Kerato- insertion with the femtosecond laser for the conus and noninflammatory thinning management of keratoconus: one-year disorders. In: Leibowitz HM, ed: Corneal results. J Refract Surg 2006; 32: disorders: clinical diagnosis and management, 2039-2042. 2nd ed. W.B. Saunders Company, 1998; 349- 6. Wollensak G, Spoerl E, Seiler T. Riboflavin/ 374. Ultraviolet-A-induced Collagen Crosslinking 3. Ectatic Disorders. Basic and Clinical Science for the Treatment of Keratoconus. Am J Course: Section 8 External Disease and Ophthalmol 2003; 135:620-627. Cornea 2006; 329-335.