Dr. Aditya Pradhan
Consultant, Cornea and External Disease,
Disha Eye Hospitals pvt. ltd., Kolkata
Povidone iodine (PVP-I) and Dexamethasone in adenoviral keratoconjunctivitis (ADKC)
Conjunctivitis is one of the most common conditions treated by ophthalmologists. It carries a significant morbidity with it in terms of loss of working hours, crossinfection and visual impairment. Adenoviruses are the most common cause of conjunctivitis and keratoconjunctivitis. EKC is caused by serotypes 8, 37 and 64 and frequently results in corneal complications and visual impairment.
The treatment of ADKC is controversial and no proven agent exists for its treatment. Kovalyuk et al conducted a prospective, double-blinded RCT of 78 eyes for the treatment of ADKC with a combination of PVP-I and dexamethasone eye drops (1.0% and 0.1% respectively). Patients were divided into 3 groups – (1) The study group: PVP-I 1.0% eyedrops and dexamethasone 0.1% eyedrops four times a day to the involved eye. (2) Control group 1: Dexamethasone 0.1% eyedrops four times a day to involved eye. (3) Control group 2: Artificial tears (hypromellose 0.3%) four times a day to the involved eye.
At every visit patients were handed a symptoms questionnaire. Tear samples were collected for rt-PCR analysis of the virus titre and thorough slit-lamp examination was carried out. Grading was done on a 4-point system. The fastest improvement (5-7 days) was seen in the study group. The slowest improvement was in the control 2 group. SEI were maximum in the control 1 group and 0% in the study group. Thus, the authors gave a strong recommendation for this treatment in ADKC.
Future studies may include a 4th arm of only PVP-I eye drops which is one of the major limitations of this RCT. Further Reading Kovalyuk N, Kaiserman I, Mimouni M, et al. Treatment of adenoviral keratoconjunctivitis with a combination of povidone-iodine 1.0% and dexamethasone 0.1% drops: a clinical prospective controlled randomized study. Acta Ophthalmol. 2017 Dec;95(8):e686-e692
Predictors of corneal perforation in MUTT II
A leading cause of monocular vision loss worldwide with approximately 2 million new cases every year is infectious keratitis. Fungal keratitis is endemic in tropical regions and accounts for almost 50% of all corneal ulcers. These ulcers are more difficult to treat than bacterial corneal ulcers and have worse outcomes.
Corneal perforation is a complication of severe fungal keratitis that occurs in upto 50% of the cases. The MUTT II was a RCT that found no benefit of adjuvant oral voriconazole in reducing the risk of perforation and/or TPK in severe filamentous fungal keratitis except for Fusarium species ulcers. Dr. Prajna et al did a secondary analysis of the MUTT II data to determine baseline patient and ulcer characteristics that predict a high risk of developing corneal perforation and/or the need to undergo TPK.
240 patients who presented with a smear-positive filamentous fungal corneal ulcer and a visual acuity worse than 20/400 (logMAR 1.3) were randomized to receive oral voriconazole or a placebo. All patients received topical voriconazole, 1%, and after the results of MUTT I became available, topical natamycin, 5%, was also administered to all patients. The primary outcome of the trial was the rate of perforation and/or the need for TPK.
122 patients (50.8%) developed a full-thickness corneal perforation/needed to undergo TPK. By performing multivariable regression analysis, the authors showed that the presence of hypopyon at baseline indicated 2.28 times the odds of the patient developing a corneal perforation and/or needing TPK. For each step increase in the infiltrate depth as measured at baseline there was 1.69 times the odds of the patient developing a full thickness corneal perforation and/or needing TPK. Study participants whose infiltrate involved the posterior third of the stroma had a 71.4% risk of developing a corneal perforation and/or needing TPK. For each 1-mm increase in the geometric mean of the infiltrate there was 1.37 increased odds of the patient developing perforation and/or needing TPK. Study participants with a baseline infiltrate size more than a geometric mean of 6.63 mm had a 66.7% risk of developing perforation and/or needing TPK.
Clinical features such as visual acuity, baseline culture positivity, type of filamentous fungal organism and duration of symptoms, and demographic characteristics, such as sex and occupation, were not significant predictors in the multivariable regression analysis.
The authors suggest that stratification of severe fungal corneal ulcers based on clinical examination at baseline can select patients who are at the highest risk of experiencing a poor outcome. This is useful to allocate resources toward high-risk patients, particularly in resource-poor settings.
Further Reading
Prajna NV, Krishnan T, Rajaraman R, et al. Predictors of Corneal Perforation or Need for Therapeutic Keratoplasty in Severe Fungal Keratitis: A Secondary Analysis of the Mycotic Ulcer Treatment Trial II. JAMA Ophthalmol. 2017;135(9):987-991.