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402 Color Atlas of Ophthalm ology

One -and-a-Half Syndrome

On e-an d -a-h alf syn drom e is also kn ow n as paralyt ic pont ine exotropia.

Presentation

In th e prim ar y posit ion th e eye th at is opposite th e side of th e lesion is exot ropic. Th e eye on th e sam e side of th e lesion looks st raigh t ah ead . Th e lesion is in th e pon t in e param edian ret icu lar form at ion (pon t in e gaze cen ter) or sixth -n er ve n u - cleus an d ipsilateral m edial longit u din al fascicu lus (Fig. 13.18A). From th e figu re on e w ill un derstan d th at on ly th e sixth n er ve on th e side opposite th e side of th e lesion w ill w ork. Th e pat ien t is n ot able to gaze w ith eith er eye tow ard th e side of th e lesion an d is n ot able to adduct th e eye on th e side of th e lesion (Fig. 13.18B). Th is is w hy th is is called on e-an d -a-h alf syn drom e, because on on e side gaze is absen t an d on th e oth er side on ly h alf th e gaze m ovem en t is presen t .

Differential Diagnosis

Myasth en ia gravis, orbit al disease, oth er supran uclear m ovem en t disorders

A

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Management

Work up an d m an age according to th e cause.

Progressive Supranuclear Palsy

In progressive supran uclear palsy th ere is loss of n er ve cells, vascu lar degen era- t ion , an d glial react ion s in th e basal ganglia an d m idbrain .

Presentation

Th e first m an ifest at ion of progressive su pran u clear palsy is an in abilit y to m ake ver t ical saccades, par t icularly dow nw ard saccades. At th is poin t , th e p at ien ts bang th eir sh in s, eat off on ly th e top par t of th eir plates, an d com p lain of being u n able to read (th ey can n ot look dow n ). As th e disease progresses, h orizon tal fast m ove- m en ts becom e involved as w ell. Even t u ally, occular m ovem en t s cease to be sm ooth an d rapid . Pu rsuit m ovem en t s becom e ch aracterist ically cogw h eel.

Differential Diagnosis

Ch ron ic progressive extern al oph th alm oplegia, m yasth en ia gravis, brain stem lesion s, cavern ou s sin u s syn drom e

Management

No t reat m en t is available except su ppor t ive care.

Parinaud Syndrome

Th ere are several m an ifest at ion s of lesion s in th e collicular area. Th e sign s are th ough t to be cau sed by pressure an d distor t ion of u n derlying st ru ct u res in th e m idbrain an d n ot by dam age to specific path w ays t raversing th e colliculi. Th e gen - eral n am e for th e clin ical pict u re produced is kn ow n as Parinaud syndrom e.

Presentation

Any com bin at ion of im paired u pw ard gaze, im paired dow nw ard gaze, pu pillar y abn orm alit ies, or loss of accom m odat ion reflex can occu r. In gen eral, loss of u p - w ard gaze associated w ith dilated pu pils th at are fixed to ligh t suggests a lesion at th e level of th e su perior collicu lu s. Loss of dow nw ard gaze, n orm al p upillar y react ion s to ligh t , an d loss of convergen ce suggest th at th e lesion is sligh tly low er in th e area of th e in ferior colliculu s. It cou ld be du e to lesion s of th e pin eal glan d, m u lt iple sclerosis, vascu lar diseases, or Wern icke en ceph alopathy.

A special t ype of nystagm u s, ret ractor y nyst agm us, is presen t . Th is is a ver y rare sign of disease in th e collicular area an d con sist s of an inw ard an d ou t w ard m ove- m en t of both eyes w h en th e pat ien t at tem pts to look upw ard . Presu m ably, it is produ ced by all th e ext raocular m u scles act ing sim ult an eou sly—jerking th e globe back in to th e orbit or at tem pted u pw ard gaze—in an at tem pt to overcom e th e in - abilit y to look u pw ard .

Differential Diagnosis

Thyroid orbitopathy, cavern ous sin us syn drom e, m yasth en ia gravis

Management

Work up an d m an age according to th e cause.

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Chronic Progressive External Ophthalmoplegia

Presentation

Th e clin ical feat u res are th e involvem en t of th e u pgaze an d th en th e lateral m ove- m en ts an d m ay later be affected in all gaze result ing in a fixed globe. Becau se th e m u scle involvem en t is sym m et rical, diplopia does n ot usu ally occu r. Th ere is also slow ly p rogressive bilateral ptosis.

Kearn s-Sayre syn drom e is a m itoch on drial cytopathy in h erited from th e m oth er. It is ch aracterized by pigm en t ar y ret in opathy w ith coarse gran ularit y. Con duct ion defects of th e h ear t can occu r. Hear t block m ay result in sudden death . Oth er fea- t u res are sh or t st at u re, m uscle w eakn ess, cerebellar ataxia, n eu rosen sor y deafn ess, m en tal h an dicap, an d delayed pu ber t y.

Differential Diagnosis

Oth er causes of paralyt ic an d rest rict ive st rabism us, m yop ath ies, m yasth en ia gravis, supran uclear palsies

Management

Treat th e associated con dit ion s. Use lu brican ts for th e exposure keratopathy an d base-dow n prism s w ith in reading glasses if th e dow ngaze is rest ricted . Pacem aker m ay be requ ired for th e cardiac con dit ion . In oculop h ar yngeal dyst rophy, dysph agia, an d recu rren t asp irat ion s m ay w arran t cricoph ar yngeal su rger y. Gen et ic cou n seling is n eeded .

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Table 14.1 Topical Antibacterial Agents

again st gram -n egat ive bacteria, are com bin ed w ith oth er an t ibiot ics to in crease th e spect rum of coverage (Table 14.2). Som e of th ese an t ibiot ics are form ulated as aqueous drops or oin t m en t . Oth ers com bin e an t iin flam m ator y agen t s to reduce a h ost in flam m ator y respon se th at can be as dam aging to ocular t issues as bacterial proteases an d toxin s (Table 14.3).

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Table 14.4 Injectable Antibacterial Agents

Injectable Antibacterial Agents

t ibiot ic t reat m en t regim en s are listed in Table 14.4. Dosage recom m en dat ion s for th ese an t ibiot ics sh ould n ot be exceeded to avoid in ducing ret in al toxicit y. Adm in - ist rat ion of th ese an t ibiot ics is con t rain dicated w h ere th ere is a kn ow n hypersen - sit ivit y to th ese agen ts.

Ocular Antivirals

More th an 45 years ago, Kaufm an first repor ted th e u se of idoxuridin e (Herp lex) for th e t reat m en t of h erpes sim plex viru s (HSV) epith elial kerat it is (Fig. 14.2). Sin ce th en , 50 an t ivirals h ave been licen sed in th e Un ited St ates; 10 n ew an t ivirals an d com bin at ion s h ave been in t rodu ced in th e last 10 years. Acyclovir (ACV) (Zovirax) h as been called th e “pen icillin of an t ivirals.” Th ere are th ree an t ivirals th at h ave purin e st r uct ures sim ilar to ACV: valacyclovir (Valt rex), fam ciclovir (Fam vir), an d gan ciclovir (Cytoven e, Vit raset). Idoxuridin e (Herp lex) an d t rifluorothym idin e (Viropt ic) h ave ver y sim ilar pyrim idin e st ru ct u res. Viropt ic is th e drug of ch oice for HSV pat ien ts. Table 14.5 is a sum m ar y of th e m ost im por tan t an t ivirals an d th eir th erapeu t ic use in viral in fect ion s of th e eye.

Fig . 14.2 Herpes simplex viral keratitis with large dendrite in late untreated stage.

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Table 14.6 Antifungal Agents to Treat Fungal Keratitis and Endophthalm itis

Antifungal Agents

Th ere is on ly on e com m ercially available topical an t ifu ngal drug (Table 14.6): n a- t am ycin (Nat acyn ). Th e rem ain ing an t ifungal agen t s in Table 14.6 m u st be extem - poran eou sly com poun ded for topical, subconju n ct ival, or in t ravit real use. All of th ese agen ts are effect ive again st yeast an d filam en tou s fu ngi. Because of poor pen et rat ion , all of th ese an t ifungal agen t s adm in istered topically for corn eal in fec- t ion s are dosed at h ou rly or 2-h our in ter vals for th e first 2 or 3 days. Th e dosing sch edu le m ay be exten ded to a drop six to eigh t t im es a day, depen ding on h ow th e in fect ion is resolving. Drug pen et rat ion in to corn eal t issu e im proves if th e epith elium is absen t . Adverse react ion s to topical an t ifungal agen ts are lim ited to local hypersen sit ivit y react ion s (e.g., conjun ct ival ch em osis an d hyperem ia, foreign body sen sat ion ).

Antiparasite Agents

Exogen ou sly acqu ired parasite in fect ion s of th e eye are cau sed prim arily by am oeba of th e gen u s Acantham oeba. Th ere are n o ch em oth erapeu t ic agen t s app roved by th e Un ited States Food an d Drug Adm in ist rat ion specifically for th e t reat m en t of Acantham oeba kerat it is. How ever, an over-th e-cou n ter arom at ic diam idin e available in th e Eu ropean Un ion , propam idin e iseth ion ate (Brolen e), h as been sh ow n to be effect ive w h en com bin ed w ith th e an t ibacterial drug n eom ycin . Propam idin e iseth ion ate is available as a 0.1%solut ion or as an oin t m en t (0.15%).