Ординатура / Офтальмология / Учебные материалы / Color Atlas of Ophthalmology The Quick-Reference Manual for Diagnosis and Treatment

16 Contact Lenses 461

Subepithelial Infiltrates

Su bepith elial in filt rates (SEIs) are an in flam m ator y react ion secon dar y to ch ron ic hypoxia or an acu te react ion th at th reaten s th e avascular corn ea an d an terior segm en t . Th is acute react ion in duces an in flam m ator y react ion th at en courages an aggregat ion or accu m u lat ion of cellu lar com pon en ts, su ch as p olym orph on u - clear cells, to m igrate th rough th e avascular corn eato an d set tle w ith in th e subepith eliu m adjacen t to Bow m an’s layer or basem en t m em bran e. Th is occurs in ~2% of len s w earers regardless of w ear an d replacem en t sch edule. Th e et iology of SEI, w h en associated w ith con t act len ses, is ch ron ic hypoxia, prolonged edem a, an im - m u n e resp on se, solut ion toxem ia, m ech an ical irrit at ion –foreign debris, or a local in fect ion or th e exotoxin s from bacteriu m residen t in th e ocular flora. Th ey are th ough t to represen t a delayed hypersen sit ivit y im m u n e respon se to viral an t igen s in th e corn eal st rom a.

Corn eal in filt rates are aggregates of gray or w h ite m igrat ing in flam m ator y cells arising from n orm ally t ran sparen t corn eal t issue. Th e in flam m ator y respon se st im ulates th e m igrat ion from th e lim bal vascu lat u re or from th e tears as a respon se to t issue dam age or a secon dar y ch em ot act ic react ion associated w ith an environ m en t al an t igen ic act ivit y or toxin s, con t act len s solut ion s, or from m icrobial organ ism s th em selves. In filt rates are defin ed as polym orph on uclear leu kocytes (n eu t roph ils) but m ay also con t ain lym ph ocytes an d m acroph ages. In con - tact len s w ear, in filt rates are m ost often sterile (n on in fect ious) but can also be in fect iou s (Fig. 16.4).

A B C

D E F

Fig . 16.4 (A) Subepithelial infiltrate with limbitis secondary to contact lens wear.

(B) Subepithelial infiltrate (SEI) secondary to extended-wear contact lenses pretreatment. (C) Epithelial compromise with migration of SEI forward through epithelium .

(D) Subepithelial Infiltrate secondary to extended-wear contact lenses post treatment with steroid. (E) Adenovirus with infiltrates. (F) Viral Infiltrates with secondary scarring. (Continued on page 462)

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Fig . 16.4 (Continued) (G) Viral infiltrates with secondary scarring topography.

G

Presentation

Th ere is an in it ial an d p ron ou n ced lim bal–vascu lar resp on se in th e area of th e ocu - lar in su lt . Su bsequen tly th ere is a release of m ediators from th e lim bal p lexu s. Th e cellular or h u m oral com pon en ts w ill m igrate in to an d th rough th e corn eal t issu e leading to th e accu m ulat ion of cells th at w ill appear as discrete w h ite-gray subepith elial p ockets or opacit ies. SEIs are seen as h azy gray, circum scribed in filt rates, at an in t raor su bepith eliu m (at th e surface of Bow m an’s layer w ith ou t in filt rat ion in to th e st rom a; th erefore, n o scarring) or w ith an terior st rom al level w ith in fil- t rat ion , th u s w ith a poten t ial for scarring. Th ey w ill be predom in an tly u n ilateral an d con cen t rated focally or diffuse w ith a preferen ce to th e lim bal an d paracen t ral areas of th e corn ea. Adjacen t to th e SEI m ay be an area of localized conjun ct ival inject ion at th e lim bal ju n ct ure of m ild to m oderate severit y. If th ere is sign ifican t corn eal vascu larizat ion of any form , th ere w ill be th e poten t ial for a h igh er in ciden ce of subep ith elial in filt rates. As SEI m igrates for w ard, th ere m ay be a subtle epith elial com prom ise or break th at w ill st ain .

Th e p at ien t m ay h ave subtle sym ptom s ranging from m ild to m oderate. With in - flam m at ion of any form th ere w ill be an associated hyperem ia localized to th e area of occu rren ce, localized edem a, an d a variable degree of discom fort . Th e pat ien t m ay also exp erien ce a m ild to m oderate level of lacrim at ion an d ph otoph obia an d a decrease in visu al acuit y based on th e locat ion of th e in filt rates, irrit at ion , an d/or foreign body sen sat ion .

Differential Diagnosis

If th ere is an oth er an terior ch am ber react ion , on e m u st differen t iate bet w een an in filt rat ive kerat it is associated w ith several oth er an terior segm en t path ologies. Th ese m ay also h ave a system ic relat ion sh ip th at n eeds to be looked for. Th ese in clu de episclerit is, m argin al ulcer, irit is, aden ovirus or EKC, or keratoconjun ct i- vit is. Addit ion ally, quiet n on in flam m ator y opacit ies m ay be in act u alit y a su btle asym ptom at ic in filt rate or a sim ple scar. Histor y in th is case w ill assist in th e differen t ial. If th ere is sign ifican t corn eal vascu larizat ion of any form , th ere w ill be th e poten t ial for a h igh er in ciden ce of subep ith elial in filt rates.

NaFl w ill be an im port an t differen t ial in dist inguish ing bet w een a scar, u lcer, or SEI. Scars an d SEI w ill n ot stain , bu t u lcerat ion w ith an epith elial defect w ill. Th is w ill allow a differen t ial bet w een SEI an d m icrobial epith elial defects. Upon t reat- m en t , th e in filt rates m ay m igrate for w ard an d disru pt th e epith elial surface, cau s- ing a top ograph ic irregu larit y an d p ossibly a n egat ive stain ing su perficial pun ct ate keratopathy. To en su re n o epith elial com prom ise an d to ru le ou t an early stage of

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m asquerader such as a h erpet ic lesion (den drit ic) Pseudom onas, Acantham oeba, or Fusarium , th e u se of rose bengal or lissam in e green w ill st ain early bu lbs of a den drit ic lesion an d detail devitalizat ion of t issue m u ch m ore readily th an sodium flu orescein .

If t h e SEI is associated w it h an ad en ovir u s, t h ere w ill be system ic an d con st i- t u t ion al fin d in gs su ch as feve r, m alaise, let h argy, m yop at hy (m u scle w eakn ess), p er iau r icu lar lym p h ad en op at hy, an d /or t h e p rese n ce of a follicu lar conju n ct i- vit is. If t h e SEI is associated w it h a ke ratoconju n ct ivit is, t h e clin ician sh ou ld con sid er t h e p ossibilit y of a t ran sm it t able d isease. An exam p le w ou ld be a ch la- m yd ial in fect ion if t h e re is a seve re follicu lar conju n ct ivit is an d h istor y of u rogen it al in fect ion . Th e p at ie n t sh ou ld be refer red to an in te r n ist , p ar t icu larly in p ed iat r ic cases.

An terior segm en t fin dings associated w ith SEI m ay also be fou n d w ith an episclerit is, w h ich m ay h ave a relat ion sh ip to a con n ect ive or collagen t issue disorder (rh eu m atoid). In flam m ator y con dit ion s, su ch as a rh eu m atologic disorder, in flam m ator y bow el disease, or sacroidosis m ay h ave an associated irit is, w h ich presen t s w ith an acute red eye, discom for t or pain , m iosis, decrease in IOP, an d a decrease in acuit y. Even th ough corn eal su bepith elial in filt rates are con sidered a rep resen t at ion of a low -grade im m u n e respon se to bacterial exotoxin s, su bepith elial in filt rates can com plem en t oth er vasost im ulator y resp on ses as seen w ith corn eal vascularizat ion , atopic or viral disease, as w ell as postsurgical causes such as p ostLASIK.

Scars an d u lcers can easily m asqu erade as an in filt rate becau se of th eir sim ilar appearan ce of h azy, gray opaqueing, n on t ran slucen t corn ea, an d locat ion at th e su bepith elial an terior st rom al level. Pat ien t s w ith corn eal scars w ill h ave a posit ive h istor y an d w ill n ot respon d to any th erapy. Also, m argin al u lcers can be m istaken for in filt rates barring th e h istor y. Ulcers w ill h ave a m ore rapid on set an d n ot iceable inject ion an d decreased com fort . Ulcers w ill ten d to be located cen t rally. In - filt rates m ay be diffuse an d cen t ral; h ow ever, m ore t ypically th ey are lim bal. SEIs w ill appear less den se th an m argin al u lcerat ion s an d dem on st rate a lesser an terior ch am ber an d conjun ct ival react ion . For a differen t ial of u lcers versu s in filt rate see

Table 16.4.

Management

In th e m ost basic t reat m en t form at it w ou ld be appropriate to discon t in ue con - tact len s u se u n t il resolu t ion . Len s w ear sh ould n ot be resu m ed u n t il all sign s an d sym ptom s are com pletely resolved . Medicat ion is usu ally un n ecessar y in m ost cases of in filt rat ive kerat it is (IK), w ith palliat ive use of preser vat ive-free ocu lar lubrican ts. Th e use of a hyperosm ot ic agen t is prescribed, su ch as NaCl 5% prescribed fou r t im es a day is m ore th an su fficien t if vision is n ot affected an d th ere is a lim ited vascular resp on se. If th ere is a greater vascu lar respon se an d vision is decreased a m ore aggressive approach w ith a steroid su ch as predn isolon e 1%four t im es a day for 1 w eek w ith a slow taper to a soft steroid (lotepredn ol 1%) is h igh ly recom m en ded . Prophylact ic use of an t ibiot ics to preven t secon dar y in fect ion or an t ibiot ic/steroid com bin at ion drops to m it igate th e in flam m ator y respon se is som et im es ben eficial. Such topicals w ould in clu de tobram ycin w ith dexam eth a- son e or lotepredn ol (Tobradex, Alcon Laboratories) or Zylet (Bau sch & Lom b) fou r t im es a day for 5 to 7 days an d slow t ap er. Cau t ion on ce again for steroid respon se an d a corn eal toxic keratop athy to tobram ycin .

Because m any cases of recu rren t IK are secon dar y to exotoxin s released by lid m argin bacteria (Staphylococcus an d St reptococcus), it is w ise to recom m en d lid hygien e in th ese cases an d to lim it len s w ear to daily w ear com plem en ted by a

16 Contact Lenses 465

peroxide care system . Lid t reat m en t w ould in clu de stan dard lid scru bs w ith n on irrit at ive agen ts, doxycyclin e 20 m g, 50 m g by m outh , or up to a 100 m g for bleph a- rit is or m in ocyclin e w ith lid clean sing (Cleeravu e–M, Ston ebridge Ph arm a, Du luth , GA) an d/or possibly cyclosporin e A drops—Restasis t w ice a day if th ere is a h istor y of ch ron ic rosacea.

Th e m ajor con cern is w h eth er th e in filt rate is act ually a n on in fect iou s sterile ulcer or con tact len s–related periph eral u lcer (CLPU). If su spicious of u lcers, p rescribe an t ibiot ics on ly. Refrain from steroid u se, cu lt ure w h en possible, an d t reat w ith flu oroqu in olon e an t ibiot ics. In th is case, th e in it ial u se of a steroid w ou ld be con t rain dicated un t il after a sh or t course of a poten t an t ibiot ic su ch as m oxifloxacin (Vigam ox, Alcon Laboratories) or gat ifloxacin (Zym ar, Allergan ). In th e case of in filt rates, th ere w ill be n o respon se to an t ibiot ics. If th ere is an u lcer, th ere w ill be a favorable respon se to an t ibiot ics, w h ich can be follow ed by th e in t roduct ion of steroids after th e loading dose h as redu ced th e bacterial burden . As an added com - m en t for pain con t rol w ith corn eal u lcerat ion , am ple cycloplegia u sing h om at ropin e 2 to 5%or a m ore frequ en t dose of cyclopen tolate 1%w ill in m any cases suffice w ith ou t th e n eed for steroid ut ilizat ion . Oral an algesia for pain can be in t rodu ced using basic acet am in oph en or ibuprofen or both as n eeded .

Th e progn osis of t reat ing in filt rates is h igh ly favorable w ith sym ptom s an d fin d - ings dissipat ing in a sh ort cou rse of a few days. In filt rates th at are den ser an d m ore cen t ralized, su ch as w ith an aden ovirus, w ill t ake longer to resolve an d m ay h ave a profoun d effect on vision requ iring longer-term care an d slow t apering of m edica- t ion s, part icu larly w h en u sing steroidal th erapy from h ard to soft steroid topicals.

Contact Lens-Related Acute Red Eye

Con tact len s-related red eye (CLARE) is an acu te, n on specific, n on ulcerat ive sterile keratoconju n ct ivit is h as in flam m ator y associat ion w ith th e adh eren ce of debris from exogen ou s m at ter, m et abolic by-p rodu cts, or vest iges of bacterial debris an d exotoxin s th at in duce th e recruit m en t of in flam m ator y cells. Th e exotoxin s are from th e breakdow n of t rapped debris or devitalized bacteria w ith in th e closed eye environ m en t . Presu m pt ively, th e greater risk is bacterial in filt rat ion an d colo- n izat ion by Staphylococcus an d Pseudom onas th at m ay lead to CLPU; th ere is suggest ion th at som e pat ien ts h ave h igh er levels of gram -n egat ive con tam in at ion .

Con tact len s acute red eyes (CLAREs) h ave a variet y of cau ses. CLARE cou ld be con sidered an in flam m ator y con dit ion associated w ith hypoxia, toxic effect s from post-len s tear debris, m ech an ical irrit at ion from a poorly fit t ing len s, dehydrat ion of th e len s du ring sleep, solut ion hypersen sit ivit y or toxicit y, or a react ion to bacterial toxin s. Du e to poten t ial hypoxic con dit ion s associated w ith len s u se, cellular glu cose convert s to lact ate. In addit ion , lactate diffu sing in to th e st rom a in creases th e osm olarit y, leading to m et abolic acidosis w ith resu ltan t corn eal edem a. A decrease in n orm al corn eal m etabolism com p rom ises corn eal t issue leading to CLARE. W h ite blood cells m igrate from th e lim bal vasculat ure an d form in filt rates in th e periph eral corn ea.

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Causes of Acute Red Eye

Th e con t act len s relat ion sh ip is via len s-in duced m ech an ical factors or from len s deposit s th at lead to inju r y or m icrot rau m a to th e corn ea. Microt rau m a en cou r- ages th e m igrat ion an d in filt rat ion of in flam m ator y cellu lar con st it u en t s. In th e case of len s deposits, th ese ser ve as an an t igen et ic sou rce th at t riggers an im m u n e respon se leading to in filt rates. Th e casu al relat ion sh ips are eith er (1) t igh t len s syn drom e, (2) tear-film deficien cy/dr y eye [i.e., con t act len s–in du ced dr y-eye (CLIDE)], (3) bacterial conju n ct ivit is, (4) in flam m ator y react ion to debris on th e back su rface debris (m et abolic an d/or exogen ous debris stagn an t bet w een th e len s an d corn eal su rface), (5) m ech an ical irrit at ion /abrasion , (6) solu t ion toxem ia/ hypersen sit ivit y, or (7) irrit at ion to len s deposits. Th e in ciden ce of corn eal fin dings w ith 30-day con t in uou s-w ear silicon e hydrogels h as been foun d at an occurren ce rate of 10%for CLPU an d 29%for CLARE (Fig. 16.5).

A

B

C

16 Contact Lenses 467

E F

Fig . 16.5 (Continued) (E) CLARE—tight lens syndrome. (F) CLARE—tight lens syndrom e—CLIDE.

Presentation

CLARE h as a gen eric appearan ce of a n on descript “red eye” directly associated w ith th e u se of con t act len s exten ded w ear m ore often th an w ith daily w ear. Th e acu te react ion could be obser ved as a n on specific red eye w ith lim bal hyperem ia, con - jun ct ival inject ion , corn eal in filt rates, an d a possible corn eal edem a th at is lim bal m ore so th an cen t ral. Upon len s rem oval, th e pat ien t m ay experien ce a greater level of ocular discom for t an d m ay exh ibit pu n ctate keratopathy eviden ce w ith posit ive fluorescein st ain ing associated m ostly w ith t rapped debris, a prim ar y cau se for th e in duced in flam m ator y con dit ion .

Th e pat ien t w ill describe a “garden variet y” red eye w ith un ilateral, som etim es bilateral, variable levels of discom fort or pain , redn ess, epiph oria, ph otoph obia, and disch arge described as w ater y to m ucopurulen t . The am ount of vision reduction , pain , and discharge w ill assist in th e different ial diagn osis an d un derlying et iology. If th e con dit ion is contact lens related, a histor y of exten ded or con tin uous len s use w ill have a h igher in cidence th an daily w ear reusable m ore so th an single-use len ses. If a contact len s patient presen ts w ith an ARE (acute red eye), it is im portan t in the h istor y to determ in e th e w ear m odalit y of th e len s. Con tinuous an d exten ded w ear schedules w ill dem on strate a h igher incidence of CLARE th an daily w ear or single use lens w ear sch edules. It should be assum ed th at all con tact len s w earers m ay h ave th e presen ce of m icrobial kerat itis an d ulcer, unt il proven oth er w ise. Th is is im portan t in clin ical m an agem en t, for m any patients ten d to self-treat or h ave been treated in appropriately for a “garden variet y conjunct ivitis” by a prim ar y care physician (PCP). Because of th e potent ial of a potent ially devastating ulcer, such as Acantham oeba, Pseudom onas, or Fusarium , it is im portant to stress to PCPs th at if a “red eye– contact lens” patient presents to th eir office, they should defer treatm en t and seek a con sult w ith an ophth alm ologist or optom etric physician .

Differential Diagnosis

As st ated, an acu te red eye presen t s as a garden variet y of red eye th at h as a dist in ct ch aracterist ic of rapid on set w h en related to con t act len s, w ith th e h igh poten t ial of being ulcerat ive, bu t can also m im ic or be directly related to m any oth er form s of ocu lar disorders su ch as bacterial, viral, allergic, or ch lam ydial in fect ion s. If th e pat ien t is n ot a con tact len s w earer, th is is n ot CLARE bu t is m ore probably a bacterial conju n ct ivit is. Th e differen t ial of th e CLARE pat ien t , due to th e con t act len s

468 Color Atlas of Ophthalm ology

associat ion , is alw ays u lcer first un t il proven oth er w ise. On ce proven oth er w ise, by cult u re or by an t ibiot ic t reat m en t , CLARE w ill rem ain as a red eye given the inflam - m ator y nature. The inflam m at ion cou ld also be an u n derlying irit is in absen ce of an an terior ch am ber react ion an d n orm al pu pils. If th ere is a sectoral com pon en t to th e CLARE, th en con sider a con tact len s periph eral ulcer (CLPU), episclerit is, su perior lim bic kerat it is (ru le out thyroid disease), vascu larized lim bic kerat it is, or ocu lar su rface in flam m at ion associated w ith a pingueculae or pter ygiu m . Th ese are an atom ically obviou s.

Management

In m any cases, th e pat ien t self-t reat s w ith over-th e-coun ter vasocon st rict ive lubrican t drop s w ith ou t relief. In m any oth er cases, th e pat ien t w ill presen t to a PCP for a garden variet y conju n ct ivit is th at is first t reated w ith an t ibiot ics. Precau t ion ar y care is requ ired . In m any in stan ces, a n on oph th alm ic–n on optom et ric provider m ay h ave star ted t reat m en t , th ereby disgu ising a possible et iology of CLARE. As such , th e pat ien t m ay h ave already been t reated w ith a sulfacet am ide 10% op h th alm ic preparat ion th at does n ot allow th e con dit ion to resolve an d in fact w orsen s th e con dit ion if th e pat ien t h as su lfa drug sen sit ivit y. Or in oth er cases, th e pat ien t m ay h ave been given a variet y of eith er am in oglycosides, flu oroqu in olon es, m acrolide, or an t iallergy m edicat ion s, som e h aving an effect or n o effect at all.

In m any cases th e sim ple discon t in uan ce of th e con t act len s an d use of glasses for a few days is sat isfactor y. If th e con dit ion resolves w ith th is m ode of t reat m en t , it suggests a sim ple m aterial an d w ear con dit ion issue th at n eeds to be addressed . If th e pat ien t rein t roduces, or rech allenges th e u se of th e sam e m aterial an d w ear sch edu le (i.e., exten ded -w ear or con t in u ou s-w ear m odalit y), an d th e con dit ion re- m an ifest s, th e rech allenge defin es th e n eed to readdress len s u se by refit t ing th e pat ien t w ith a n ew m aterial, w ear sch edu le, an d care p rodu ct .

Treat m en t som et im es determ in es th e differen t ial diagn osis in th e absen ce of corn eal fin dings. As th e caveat w ou ld suggest , “do n o h arm ,” th erefore it is best to t reat th e eye w ith an t ibiot ics, an d if n eeded for cycloplegia, for a m in im um of 24 to 48 h ou rs prior to th e in t rodu ct ion of a steroid to avoid a possible exacerbat ion of an u n derlying ulcerat ive or h erpet ic: viral, fungal, or protozoan en t it y. Aggressive an t ibiot ic th erapy sh ou ld be th e first course of th erapy w h en m aking th e assum p - t ion of ulcer, an d a flu oroqu in olon e sh ould be in t roduced . Moxifloxacin (Vigam ox, Alcon Laboratories) or gat ifloxacin (Zym ar, Allergan ) sh ould be th e first ch oice; h ow ever, th ird -gen erat ion flu oroqu in olon es w ill su ffice. If th ere is som e resolu - t ion w ith th e an t ibiot ic, th en th e CLARE w as n ot in flam m ator y but in fect iou s. If th ere is m in im al to n o respon se to an t ibiot ics, th en a steroid, such as predn isolon e 1% fou r t im es a day, to rid th e in flam m ator y com pon en t of CLARE can be in t rodu ced safely, after th e loading dose of an t ibiot ic redu ces th e bacterial load .

After th e successfu l resolu t ion of CLARE, th e pat ien t sh ould be refit w ith a n on - ion ic, h igh -w ater-con ten t , deposit-resistan ce len s or a n on ion ic silicon e hydrogel len s m aterial w ith th e rest rict ion to daily w ear u se an d n o exten ded or con t in u - ous w ear. Peroxide-based care produ ct s are recom m en ded w ith vigorous rubbing to clean se debris an d con t am in an ts. Also con sider gas-perm eable len ses th at w ill allow for n ot on ly an appropriate h igh oxygen perm eabilit y bu t also a flat ter or hyperbolic periph eral cu r ve an d edge design th at facilit ates su fficien t tear pu m p an d exch ange.

16 Contact Lenses 469

Contact Lens-Induced Dry Eye

Som et im es described as th e m in im al sicca syn drom e, con tact len s–in duced dr y eye forces a borderlin e keratoconju n ct ivit is sicca pat ien t in to a full m an ifest at ion of sym ptom s an d fin dings associated directly w ith a fu lly m an ifested dr y eye w ith th e in t rodu ct ion of a con tact len s on to th e ocu lar su rface. Th e len s act s as an obst a- cle an d com pet itor w ith th e n at ural tear film , leading to in sult th at w ill ju st ifiably cau se a react ion by th e eye leading to th e ch ange in its n at u ral tear film physiology an d m etabolism . Th is w ill lead to in toleran ce, in flam m at ion , an d a com prom ise of th e ocu lar su rface.

Causes of Contact Lens-Induced Dry Eye

Th e n orm al tear-film environ m en t is at t acked by th e in t roduct ion of a con t act len s. In it ially, th ere is a reflexive in crease in tear product ion . How ever, over t im e tear produ ct ion w ill “fat igu e” th e system , decreasing th e effor t s of th e lacrim al system an d in creasing th e poten t ial for con t act len s deposits, m icrobial in fect ion , an d corn eal in filt rat ion , corn eal edem a, an d u lt im ately p at ien t dissat isfact ion an d in toleran ce to con tact len ses.

Th e in t roduct ion of th e con t act len s to th e ocular surface w ill disru pt th e h o- m eostat ic balan ce of th e tear film , requiring a n ew balan ce to be establish ed be- t w een th e pre-len s ocular tear film an d th e post-len s ocu lar tear film –precorn eal tear film . As deposit s or su rface film accum u lates, blin king com presses th e tear film an d rem oves th e lipid -con t am in ated, hydroph obic m u cu s an d debris from th e len s–tear su rface. Th e in tegrit y of th e precorn eal an d len s tear film is directly propor t ion al to th e abilit y to m ain t ain proper con tact len s w et tabilit y an d len s su rface hydrat ion .

If th e lipid layer is poor, th e evaporat ive process in creases, leading to a greater loss of aqueous an d th e in duct ion of a for w ard osm ot ic draw across th e con t act len s surface leading to len s dehydrat ion an d corn eal desiccat ion . W ith len s dehydrat ion , th e hydroph ilic len s w ill steepen , m ech an ically pu lling on a w eaken ed ep ith elial su rface, allow ing for corn eal com prom ise visualized as cen t ral corn eal epith elial desiccat ion an d/or cell jun ct u re split t ing or separat ion .

Also, w h en th e ocular su rface becom es “u nprotected,“ th ere is th e developm en t of n eu ron al hyposen sit ivit y associated w ith hypoxia an d th e barrier effect created by th e con t act len s in terface. As th e con tact len s develops a su bst an t ial dehydra- t ion it w ill ten d to vau lt aw ay from th e ocu lar su rface, leaving an exposed gap bet w een th e post-len s surface an d th e corn eal su rface. Th e gap h ow ever is n ot flu id filled an d leaves th e ocu lar surface u nprotected, leading to com prom ise an d dessicat ion of th e epith eliu m an d aberrat ion to n eural regulat ion an d biofeedback to th e lid st ru ct ure (Fig. 16.6).

470 Color Atlas of Ophthalm ology

A

B

C D

Fig. 16.6 (A) Classic appearance of contact lens acute red eye (CLIDE) in patient exhibiting circumlimbal injection, marginal erythema, conjunctival injection, and immobile lenses. (B) Minim al lacrimal lake as demonstrated by lissam ine green. (C) Disrupted tear film spread with subsequent paracentral punctate keratopathy associated with CLIDE.

(D)Lissamine green staining of the conjunctiva in a CLIDE patient.

Presentation

Th e pat ien t w ill presen t w ith a CLARE-t ype ap pearan ce th at h ad been som ew h at ch ron ic. Th e eyes w ill be described as feeling t ired, dr y, an d irritated an d alw ays red, par t icularly later in th e day. It w ou ld also be n oted th at pat ien t s h ave difficu lt len s rem oval an d describe a feeling of relief u pon len s rem oval. Often th e pat ien t w ill proceed w ith vigorou s eye rubbing after len s rem oval. In som e cases of difficu lt len s rem oval, th e eye feels overly sen sit ive an d presen t s w ith an in crease in inject ion du e to th e in adver ten t rem oval of su perficial epith elial t issu e an d n eu ro- n al exp osure due to epith elial com prom ise during len s w ear associated w ith len s dr yn ess an d bin ding. Su pplem en tat ion w ith topical drops su ch as lubrican t s m ay