Case of the Month

Interesting and Challenging Problems Seen at Sydney Cornea Clinic

Common Retinal OCT Findings

Sydney Cornea Clinic - Saturday, April 01, 2017

At our recent Optometry Information, Dr Alex Hamilton presented an informative session on Common Retinal OCT Findings. The presentation is linked here.

Acute Red Eye

Sydney Cornea Clinic - Saturday, April 01, 2017

At our recent Optometry information evening Dr Alex Hamilton presented on the Important Causes of a Red Eye that Need Urgent Referral. This informative presentation is linked here.

Scedosporium Prolificans Corneal Infection

Sydney Cornea Clinic - Tuesday, September 01, 2015

MR W, a 27 year old recycling collector presented with a painful left eye, having possibly had a foreign body in the left eye for several days. He had a past history of Herpes Simplex Virus Keratitis (HSV) affecting the left eye. 

He was seen elsewhere and was treated for presumed HSV keratitis with acyclovir eye ointment five times daily and prednisolone acetate eye drops (Prednefrin Forte) every 2 hours. After several weeks of treatment Mr W was worsening and was seen here. 

At this time the visual acuity in the left eye was 6/60, and the left eye had the following appearance:



Questions


1. What are the possible diagnoses?

2. What is is the management?

Answers Follow Below...



Possible Diagnoses

The appearance shows a large corneal infiltrate with a "satellite" lesion beside the main infiltrate. There is a small hypopyon visible inferiorly. The eye is very injected. 

The appearance is suggestive of a microbial keratitis. Whilst Herpes Simplex Virus Keratitis is a possibility, the lack of response to prolonged treatment suggests that other organisms are more likely. Bacterial, fungal and atypical organisms are possibilities. The relatively slow course of the condition and the presence of a "satellite" lesion are suggestive of a fungal keratitis. Corneal scraping is required to obtain the diagnosis.

Management

The patient was admitted to hospital for urgent investigation and treatment. Corneal scrapes were performed for microscopy, along with cultures for bacteria and fungi. HSV PCR testing was performed. 

Mr W was commenced on intensive fortified topical antibiotics in the form of gentamicin 0.9% and cephalothin 5% hourly, along with oral valacyclovir (Valtrex) 1000 mg twice daily. The topical steroids were stopped. In addition homatropine 2% three times daily was used to dilate the pupil.

Microscopy and culture revealed a filamentous fungal infection:



With the diagnosis of a fungal keratitis, topical Natamycin eye drops hourly was commenced.

Several days later, microscopy revealed the fungus to be Scedosporium Prolificans, sensitive to Voriconazole anti-fungal agent. The antifungal treatment was changed to Voriconazole orally and in compounded drop form. 

Despite intensive treatment for two weeks, the keratitis worsened and was invading the cornea close to the limbus. At this stage, the decision to perform a corneal transplant was made.



Following corneal transplant surgery and several months of recovery, Mr W recovered to a visual acuity of 6/7.5. Several years later, the transplant continues to function well and Mr W is maintaining excellent vision in both eyes.

Commentary


Mr W demonstrates the importance of reconsidering and re-evaluating the diagnosis when the clinical response is not as expected.

Microbial keratitis is an urgent situation which requires immediate and intensive treatment. Whilst fungal keratitis is relatively rare, and bacterial keratitis is much more common, there are a few hints that suggest that fungal keratitis is a possibility here. The occupation of Mr W as a recycling collector suggests organic matter and less common organisms may be a possibility. The relatively slow progression over several weeks suggests a slower growing organism such as a fungus. The presence of a "satellite" lesion is also characteristic of a fungal infection. Despite these hints, only a confirmed diagnosis on culture and microscopy can confirm the organism. 

Fungal keratitis can be very difficult to treat. Scedosporium Prolificans is often a resistant organism, and despite being treated appropriately with anti fungal medication, the infection continued to spread. In such cases it is prudent to remove the infection with a corneal transplant prior to the infection spreading to the sclera. Despite the difficulties in such cases they are typically successfully treatable as seen in this case.




Unusual cause of vision loss after Corneal Transplant

Sydney Cornea Clinic - Saturday, August 01, 2015
Mr J, age 70, presented with a rapid deterioration in vision in the right eye over one week. Mr J has a past history of keratoconus, with a full thickness corneal transplant in the right eye performed thirty years ago. Mr J wears contact lenses in both eyes and normally sees well in both eyes. 

The loss of vision in the right eye was not associated with any other symptoms, in particular there was no pain, redness or light sensitivity. There had been no previous issues with the corneal transplant. 

The examination revealed visual acuities of 6/120 in the right eye and 6/9 in the left eye. The cornea transplant in the right eye revealed severe corneal oedema affecting 80% of the transplant, with a small area of the transplant superiorly still being clear. The eye was not inflamed, there was no keratic precipitates and no anterior chamber activity. 

Corneal topography revealed a thickened cornea and was otherwise not helpful.

Anterior Segment OCT revealed the following:



Questions


1. What are the common causes of corneal transplant oedema?

2. What is the likely cause in this case?

Answers Follow Below...

Answers

1. The common causes of corneal oedema in a corneal transplant are:
  • Acute Corneal Transplant Rejection which can occur for a number of reasons, including infection, sutures loosening or breaking, not using steroid drops when required or in some cases for no obvious reason.
  • Corneal Transplant Endothelial Failure - simply deterioration of the transplant over time with loss of endothelial cells.
2. The likely cause in this case is spontaneous detachment of Descemets' Membrane. This rare but recognised problem can occur at any stage after corneal transplant surgery, and can be easily confused for corneal transplant failure. Often Descemets' Membrane can be difficult to visualise due to overlying corneal oedema. Anterior segment OCT can be very useful in assisting with the diagnosis of this problem. The detached Descemets' Membrane can be clearly visualized on the OCT image above.

Treatment

Spontaneous Descemets' Detachment can be treated by injection of gas, either air or longer acting gas such as SF6 into the anterior chamber, and then having the patient posture to allow the air to reposition the membrane. If this treatment is unsuccessful, repeat corneal transplantation, either endothelial or full thickness can be performed.

In this case, air injected into the anterior chamber successfully cleared the corneal transplant.

The follow up anterior segment OCT is shown here:



Descemets' Membrane is now attached.

Mr J returned to wearing his contact lens in the right eye, with a visual acuity of 6/9. Certainly a quicker recovery than a repeat corneal transplant!




Complex Cataract Surgery

Sydney Cornea Clinic - Tuesday, July 28, 2015
Cataract surgery is one of the miracles of modern medicine. Commonly performed, largely painless, with a rapid recovery in vision for the large majority of people who undergo the surgery. There are continuing advances in the precision of the surgery, and lens choices which are moving the state of the art forward. Most cataract operations performed have eyes that are otherwise normal apart from the cataract. There are circumstances where the normal structures in the eye are compromised, which can make cataract surgery much more difficult to perform, and require more complex surgery. 

In this example the patient had suffered an injury many years ago to the eye, known as a penetrating eye injury where the eye had been cut open by the injury. This injury required surgery at the time to close the laceration and save the eye. As a result of the injury there is a large scar in the cornea and approximately one third of the iris was lost. More importantly from the point of view of cataract surgery, approximately 40% of the zonules were damaged. 

The zonules are tiny thread like structures which hold the natural lens in place, and which form part of the structure supporting the artificial intraocular lens in the eye following cataract surgery.  More recently, this person noticed rapidly deteriorating vision and increasing glare. A dense cataract or clouding of the natural lens was found when the eye was examined. Because of the loss of the zonules, the new intraocular lens would require additional support to remain stable in the eye. 

When there is a small area of zonule loss, a capsular tension ring (CTR) can be used to improve the lens stability. When a large area of zonules are lost, the capsular tension ring alone is not adequate to support the lens, as the CTR can only distribute the strength of the remaining zonules rather than add to the strength of the zonules.  In cases such as this the option is to implant a modified form of capsular tension ring where the ring is sutured to the wall of the eye. This Cionni ring increases the zonular strength and allows for a greater degree of stability of the intraocular lens following surgery. 

The video below demonstrates how this procedure is performed. The patient had a good outcome with improved vision and reduced glare. Given the severity of the earlier injury the vision did not return to a normal level, however the vision achieved was useful to the patient and similar to that achieved after the injury occurred and before the cataract occurred. There are a number of circumstances where cataract surgery can be more difficult due to zonule problems, iris problems and other abnormalities of the structure of the eye. As with all surgery it is important to tailor the surgical approach to the eye and to the needs of the individual.

  • Cataract Surgery with Cionni Ring