ophtalmology presentation

1. Urrets-Zavalia Syndrome

2. Definition and Historical Background
• In 1963, Alberto Urrets-Zavalia described six patients with wide and rigid pupils,
multiple posterior synechiae, and iris atrophy after undergoing PKP.
• Historically, UZS) has been defined as a fixed and dilated pupil following PKP) for
keratoconus in patients who receive mydriatics.
• The reported incidence of UZS after PKP varies widely, ranging from 0 % to 17.7%.
• UZS usually occurs unilaterally despite bilateral surgery.

3. • Possible risk factors for UZS are
– increase IOP during or after surgery,
– use of atropine or other mydriatic agents,
– presence of keratoconus,
– viscoelastic material left in the eye,and
– AC inflammatory reaction in the postoperative period.

4. Pathogenesis
• The mechanism of UZS has not been fully determined & is probably multifactorial.
• The most widely accepted theories are ischemia of the iris and acute rise in IOP.
• Iris abnormalities, which may be more common in keratoconus, the instillation of
strong mydriatics, and bringing the iris into contact with the peripheral cornea to
produce peripheral anterior synechiae may also be triggers.

5. Iris Ischemia and Atrophy
• The leading explanation for the development of UZS is ischemic atrophy of the
sphincter muscle secondary to iris strangulation with resultant pupil dilatation.
• The cause for iris ischemia could be
– an acute post-operative increase in IOP,
– compression of iris vessels against the incision edge of the host cornea as the lens-iris
diaphragm moves forwards during surgery, and
– visco-elastic material left in the anterior chamber angle.
• Patients who had a fixed dilated pupil after PKP reveals delayed and segmental filling of the iris vessels. The
vessels are also tortuous, and at a late stage the iris vessels leak.
• These angiographic findings are compatible with severe iris ischemia. Surgical trauma to the iris caused by
the trephine or scissors can also result in a fixed dilated pupil.

6. Increased IOP
• Tuft et al reported three patients with UZS following PKP who had transient elevated IOP postoperatively.
They speculate that raised IOP occluded the iris vessels. The low rigidity of a keratoconus eye may allow the
occlusion of vessels at the root of the iris within the sclera. [1] Figueiredo et al found that elevation of the
IOP within 24 hours after PKP was a significant risk factor in the development of UZS. [2] Walton et al
stated that UZS is unequivocally the result of acute elevation of the IOP to a level sufficient to cause iris
ischemia and secondary pupillary sphincter atrophy,resulting in permanent mydriasis.
• There are other reports of UZS patients with normal IOP and none of the cases in Urrets-Zavalia’s original
article had an elevated IOP. Alberth and Schnitzler reported a 10% incidence of irreversible mydriasis
following PKP, but IOP was normal in all patients. [3]
• Another hypothesis is a toxic reaction of the iris to topical agents. Nizamani et al reported fixed and dilated
pupils as a sequela of Toxic Anterior Segment Syndrome. [4]

7. Associations with Ophthalmic Surgeries
Following PKP
• The majority of the reports of fixed and dilated pupils are in the setting of PKP.
• The reason why this occurs much more often after PKP than after other surgeries is not fully understood,
and several explanations,especially regarding the surgical technique have been offered.
– In PKP, the iris vessels are more vulnerable to compression against the incision edge of the host cornea,which may
lead to iris ischemia.
– The trephine or the scissors used to cut the cornea may cause trauma to the sphincter.
– During PKP, pressure from the vitreous can cause the lens to prolapse upward resulting in damage to the iris.
– To prevent the forward vitreous pressure, Price developed a technique of suturing the donor on top of the recipient
cornea and had no further cases of fixed and dilated pupils.

8. • Glaucoma surgeries such as trabeculectomy, goniotomy and iridoplasty may also
cause fixed and dilated pupils.
• Cataract surgery may result in fixed and dilated pupils.The viscoelastic material
was suspected to be toxic to the sphincter or vasculature of the iris resulting in
fixed dilated pupil.
• UZS have also been reported after phakic IOL and intracameral gas injection.

9. Clinical Findings
• A fixed, dilated pupil will not react to light or accommodation and will usually be
noticed during the immediate postoperative period .
• Jastaneiah et al reported that a dilated pupil will be detected by the first two
postoperative days in 80.9% of patients.[10]UZS is also reported to occur up to 5
months postoperatively.
• There is a diffuse atrophy of the anterior layers of the iris and pigmentary
granules on the corneal endothelium and the anterior capsule of the lens in the
incomplete and sometimes transient form of UZS, and reduction in pupil size is
possible over time in such cases

10. • Patients with the complete form have marked atrophy of both the
anterior and posterior layers of the iris, which makes the mydriasis
irreversible. Posterior synechiae and opacities on the anterior capsule
(glaukomflecken) are then common.
• The permanent mydriasis brings the iris close to the trabecular
meshwork and causes adhesions and occlusion of the angle, which
results in secondary angle-closure glaucoma.

11. Prevention
• Preventing Urrets-Zavalia syndrome is difficult because the precise
cause of the syndrome is uncertain.
• Preoperative
• Intravenous mannitol given preoperatively was found to decrease the
rate of fixed, dilated pupil from 4%to 1.5%. The mannitol reduces
vitreous volume and could prevent iris strangulation.
• YAG laser iridotomy performed one day prior to PKP was shown to
prevent UZS.

12. Intraoperative
• Some steps are needed to be taken during surgery to prevent the
occurrence of UZS.
– First, the anterior chamber should be kept deep throughout.
– Second, special care must be taken to avoid surgical trauma to the iris.
– Third, the surgeon should consider performing peripheral iridotomy that can reduce
the risk of iris strangulation and pupillary block.
• Postoperative
– Close IOP control is needed during the first 24 postoperatively in all
patients undergoing PKP, particularly for keratoconus.Avoid mydriatics.

13. Management
• General treatment
– Spontaneous partial recovery is possible in UZS.
• Medical therapy
– Some reports in the literature were suggesting the use of dapiprazole and
guanethidine drops, which are sympatholytic agents, there were suggested as
a measure to cope with the hypertony of the sympathetic system of the iris
and to induce miosis after UZS has occurred

14. • Surgery
– When the cause for a fixed dilated pupil is a shallow anterior chamber and as
a result an iris-host cornea touch,that contact should be broken by a
cyclodialysis spatula while simultaneously reforming the anterior chamber to
avoid recurrence of the iris-cornea touch.
– The pupil will start to contract as soon as this contact is broken

15. oti
• If UZS has developed secondary to elevated IOP because of
blood or viscoelastic residue left in the anterior chamber,
immediate anterior chamber washout is recommended.
• Several reconstructive surgical treatments are available for
symptomatic permanent mydriasis. These include
– corneal tattooing, a black diaphragm intraocular lens, and iris sutures.
– A femtosecond-assisted keratopigmentation technique was described
in order to improve visual complaints and cosmetic appearance.

16. Orbital Ultrasonography
• U/S is rapid noninvasive screening method to examine orbital lesions.
• CT is the investigation of choice for orbital lesions, as it produces excellent
tissue details of surrounding structures with clear delineation of anatomy.
• Ultrasonography has advantage of rapidity and easy accessibility.
• With its ability to identify the orbital walls, retrobulbar fat,ocular muscles,
optic nerve and orbital mass, it is a usefulfirst line of investigation in orbital
diseases and proptosi

17. • The aim of orbital imaging is
– to demonstrate an orbitallesion,
– determine its position and
– extent within the orbit.
• At times it becomes difficult to predict the pathologicalnature of
lesion, as most of ultrasonographic features arenonspecific, therefore,
clinical history is important.

18. Examination Technique
• Short focus high-frequency transducers with frequency ranging
from 5 mhz to 10 mhz are the ideal probes to examine the orbit.
• Direct contact method is the ideal technique.
• The examination is carried out in both transocular and paraocular
approaches.
• The orbit is examined in transverse, axial and longitudinal views.

19. • Transocular method clearly delineates mid and posterior
orbital masses.
• The paraocular approaches clearly demonstrate anterior
lesions and relationship to the globe and orbital wall.
• The paraocular approach is used in both transverse and
longitudinal directions.
• The orbit is examined in all four directions: superior,
inferior, medial(nasal) and lateral (temporal).

20. • The optic nerve is echo poor in texture, whichlies freely in
the retrobulbar fat, which is highly echogenic.
• It can be seenongitudinally and transversely as oval
hypoechoic shadow.

21. • The four recti muscles arise from a tendinous ring at theapex broaden out to
form a cone of muscles around the eyeball.
• The orbital muscles are seen as thin, echo poor straps.
• These tendons are narrowed anteriorly and muscle belly is more fusiform in
shape.
• The medial and lateral rectiare seen best in horizontal planes and superior
and inferior recti are seen in vertical planes.
• The inferior obliquemuscle is seen behind the globe just below the macula.
• The superior oblique is seen in superomedial part of theorbit. Its
sonoappearance is similar to the recti muscleappearance.

22. • In thyrotoxicosis (Graves’ disease), ocular muscle involvement is common.
However in 3 to 5% of the cases hypertrophied ocular muscles compress the
optic nerve resultinginto severe threat to the vision.
• HRSG is good noninvasivemethod to evaluate hypertrophy of muscles.
• Medial rectusmuscle is taken as a standard and thickness of more than4 mm
is taken as hypertrophy of muscle suggestive ofGraves’ disease. Typically the
enlargement takes place inmuscle belly.
• Other orbital features include increasedorbital fat and orbital edema. The
edema appears asechopoor areas in orbital fat

23. • HRSG shows a low level echo complex mass in retrobulbar
area layering of fluid is seen indicating a retrobulbar abscess.
HRSG shows low-level echo complex mass in retrobulbar
space with anterior displacement of eyeball. Few internal
echoes areseen in it suggestive of retrobulbar hematoma