Timing of Ocular Hypertension After Pediatric Closed-Globe Traumatic Hyphema: Implications for Surveillance





Highlights





  • Traumatic hyphema with closed-globe injury leads to ocular hypertension often (40%).



  • Ocular hypertension occurs over a broad time frame after hyphema.



  • Long-term surveillance for ocular hypertension after traumatic hyphema is necessary.



  • Patient characteristics can predict the likelihood of ocular hypertension.



  • A risk-stratification tool for surveillance of ocular hypertension after hyphema is proposed.



Purpose


To evaluate the timing of ocular hypertension (OHT) after pediatric closed-globe injury (CGI) and traumatic hyphema. We hypothesize that OHT will occur at different times based on injury characteristics.


Design


Retrospective, cohort study.


Methods


Setting : Single-center, tertiary-care, pediatric hospital. Participants : Subjects included patients ≤18 years of age at the time of injury who suffered CGI and traumatic hyphema between 2002 and 2019. Observation Procedure(s) : Intraocular pressure and injury demographics were abstracted for every visit after injury. OHT was defined as >21 mm Hg at presentation or after a reading of ≤21 mm Hg at a prior visit. Main Outcome Measures : The primary outcome measure was the timing of OHT categorized into 4 periods: presentation, acute (days 1-7), subacute (days 8-28), or late (day >28). Secondary outcome measures were identification of risks factors for OHT by multivariable logistic regression.


Results


OHT occurred in 119 of the 305 (39%) subject eyes. OHT occurred in 35 patients at presentation, 69 times acutely, 35 times subacutely, and 36 times late. Pupil damage predicted acute-period OHT ( P = .004). OHT at presentation predicted subacute period OHT ( P = .004). Iridodialysis and cataract predicted late-period OHT ( P = .007 and P < .001, respectively).


Conclusions


OHT after CGI and traumatic hyphema in pediatric patients is common. Injury demographics predict this complication. Integration of these risk factors with current literature allows proposal of a risk-stratification tool to guide efficient surveillance for OHT.


T raumatic hyphema is defined as a collection of blood in the anterior chamber after injury. It commonly occurs secondary to closed-globe injury (CGI), as this mechanism of injury results in the transmission of substantial force to the eye. This force causes a contraction and re-expansion of the globe, which can shear iris and ciliary vessels leading to bleeding in the anterior chamber. Traumatic hyphemas are relatively common among children and are often caused by injuries sustained during sports or play.


There are numerous vision-threatening complications that arise from traumatic hyphemas. , These can be categorized as being secondary to the blood in the anterior chamber, or as being secondary to anatomical injury. Elevated intraocular pressure (IOP), or ocular hypertension (OHT), is a vision-threatening complication, which can occur after traumatic hyphema through numerous mechanisms spanning both categories. IOP may be elevated on presentation because of blood volume in the anterior chamber, or it may be elevated later due to clogging of the trabecular meshwork with clot and fibrin degradation products, steroid side effect, or chronically decreased outflow secondary to angle dysfunction. , , The time course of OHT varies by etiology. ,


OHT can lead to glaucomatous damage and poor visual outcomes. , The risk of untreated OHT compels providers to schedule patients for frequent follow-up after their injury, which can be burdensome. At Boston Children’s Hospital (BCH), patients are told to follow up daily for 3 days, then once every 3 days, and finally on progressively lengthened intervals depending on their clinical course. This follow-up is necessary to track visual improvement, surveil for developing or worsening complications, and to perform gonioscopic examinations to identify angle recession and to risk stratify patients for developing late-onset OHT. Despite varied reasons for frequent follow-up, the high frequency of visits is largely driven by concerns for OHT requiring medical or surgical treatment. A recent, large retrospective study from India showed 20.6% of eyes developed elevated IOP after CGI with nearly one-quarter of CGI eyes requiring surgery to achieve IOP control.


Although numerous studies have shown associations between patient characteristics and eventual development of OHT, , , we are not aware of any that have focused on the timing of OHT in a pediatric population with CGI and hyphema. This study aims to evaluate the timing of OHT after CGI and hyphema. We hypothesize that the timing of the OHT may be predicted by examination characteristics and gonioscopic findings, and we believe that predictive factors may be used to risk-stratify surveillance for OHT in pediatric patients after CGI and traumatic hyphema.


METHODS


A retrospective cohort study of all patients who presented to BCH between January 2002 and April 2019 with CGI and traumatic hyphema was performed. This study was conducted with BCH institutional review board approval before the study began, and it adhered to compliance with the Health Insurance Portability and Accountability Act. Patients were identified by querying billing records using International Classification of Diseases, Ninth Revision and International Classification of Diseases, Tenth Revision codes for hyphema (364.41/H21.00-03), blunt ocular trauma (918.9/S0590x_, S0591x_, S0592x_), and ocular contusion (921.3/S05.10x_, S05.11x_, S05.12x_). Cases were included if they met the following criteria:



  • 1.

    CGI;


  • 2.

    eye trauma leading to presentation to BCH or Massachusetts Eye and Ear within the study period;


  • 3.

    presentation to BCH within 3 days of the trauma;


  • 4.

    follow-up for at least 3 visits and 21 days from the injury; and


  • 5.

    treatment of the injury at BCH.



For patients who met the inclusion criteria, abstracted data from chart review included:



  • 1.

    mechanism of injury;


  • 2.

    demographic information;


  • 3.

    medical and ocular history; and


  • 4.

    examination results of all ophthalmologic examinations.



Visual acuity was converted into the logarithm of the minimum angle of resolution for analysis. “Counting fingers,” “hand motion,” and “light perception” were assigned Snellen values of 20/1,500, 20/4,000, and 0.04/200, respectively. Preverbal and nonverbal children were tested with preferential looking testing and “fix and follow” visual behavior when possible. Microhyphema included those patients with the denotation of 0.5+, 1+, 2+, 3+, or 4+ cells in the anterior chamber; macrohyphema was classified as any layered hyphema and expressed as a percentage of anterior chamber height. When layering was expressed in millimeters in the chart, a vertical corneal diameter of 10 mm was assumed, and the value was converted to a percentage. Hyphemas were then graded categorically for analysis as microhyphema, grade 1 (layering of 1%-33%), grade 2 (34%-50%), grade 3 (51%-99%), or grade 4 (100%).


An individual occurrence of OHT was defined as an IOP measurement >21 mm Hg at presentation or after a reading at the prior visit of ≤21 mm Hg. If numerous readings were taken at 1 visit, IOP measurements were averaged and were rounded to the nearest whole number. The timing of OHT was categorized into 4 periods: presentation (day 0), acute (days 1-7 after injury), subacute (days 8-28), or late (>28 days). These time intervals were chosen to represent clogging of trabecular meshwork (both day 0 and days 1-7), side effect of steroid treatment, and decreased facility of aqueous humor outflow secondary to angle dysfunction, respectively. ,


Anatomical damage of the eye from CGI was abstracted as well. Traumatic mydriasis, trauma to the iris, and pupil damage were recorded as the variable “pupil damage.” Rebleed, iridodialysis, cataract, vitreous hemorrhage, macular edema, and retinal hemorrhage were recorded for each subject. Angle recession characteristics from the gonioscopic examination were converted into a categorical variable with 0 indicating no angle recession, 1 indicating <180° of angle recession, and 2 indicating ≥180° of angle recession. These groupings were based on data suggesting that the degree of angle recession affects outcomes.


The database was created in Microsoft Office Excel (Microsoft Corporation, Redmond, Washington, USA), and the statistical analyses were done using IBM SPSS Statistics (IBM, Armonk, New York, USA). Continuous data were summarized using medians and interquartile ranges and were compared by the Mann-Whitney U test. Categorical data were summarized using frequencies and percentages.


The primary outcome measure was specified as the timing of each episode of OHT with respect to 4 periods after injury: at presentation, acute, subacute, and late.


Secondary outcome measures were risk factors associated with OHT in each time period (acute, subacute, and late) by multivariable logistic regression analysis with backward selection using the Wald test. Three models were created:



  • 1.

    Acute-period model



    • a.

      Variables included were age, presenting visual acuity, hyphema grade, pupil damage, and iridodialysis given that these variables were evident on presentation.


    • b.

      Because the purpose of this model was to understand which patients without OHT at presentation might develop it in the acute period, this model was based only on patients without OHT at presentation.



  • 2.

    Subacute-period model



    • a.

      Variables included were those used in the acute model plus OHT at presentation, OHT in the acute period, and rebleeding episodes.



  • 3.

    Late-period model



    • a.

      Variables included were those used in the acute model plus the presence of cataract, angle recession, OHT at presentation, OHT in the acute period, and OHT in the subacute period.


    • b.

      Because the purpose of this model was to surveil long-term complications of the injury, additional clinically relevant variables were added.




Results of logistic regression modeling were recorded as odds ratios (ORs) with corresponding 95% confidence intervals (CIs) and P values.


An expected sample of 300 patients was assumed based on practice patterns within the group. Using a Wald test in multivariable logistic regression modeling, a total sample size of 300 children with CGI would provide 80% power for detecting a moderate OR associated with OHT of 1.5, assuming an incidence rate of 30% of OHT during any period and a 2-tailed alpha level of 0.05. Power calculations were performed using nQuery Advisor (version 8; Statistical Solutions Ltd, Cork, Ireland). All P values <.05 were considered statistically significant. No further adjustment for multiple comparisons was made to avoid type II errors. Variables were checked for collinearity using variance inflation factor values of >3 prior to inclusion in the multivariable logistic regression model.


RESULTS


The billing queries resulted in 1,259 unique patient records; 305 eyes of 304 patients met inclusion criteria. Demographics of the study population are outlined in Table 1 . Patients had a median age of 11 years with 76% being male. Self-identified race showed the majority of the cohort to be white (n = 204; 67%). The cohort collectively had a median follow-up of 591 days with 174 (57%) having greater than 180 days of follow-up. At presentation, 95% (290/305) of patients in this cohort had a numerical visual acuity measurement, and 97% (297/305) of this cohort was started on topical steroids.



Table 1

Demographic Characteristics of Children With Closed-Globe Injury and Hyphema (N = 305)












































































Variable N (%)
Median age (y) 11.3 (IQR: 8.7-14.2)
Sex Male 231 (76)
Self-identified race Asian 9 (3)
Black/African American 24 (8)
Hispanic/Latino 4 (1)
White 204 (67)
Other 15 (5)
Unable to tell 42 (14)
Declined 6 (2)
Eye involved Right 158 (52)
Duration of follow-up (d) ≤30 24 (7)
31-60 60 (20)
61-90 17 (6)
91-180 30 (10)
>180 174 (57)
Number of visits at each time period Day 0 231 (9)
Days 1-7 817 (33)
Days 8-28 497 (20)
Days 29-182 412 (17)
Days 183-365 150 (6)
Day 365+ 359 (15)

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Jan 3, 2022 | Posted by in OPHTHALMOLOGY | Comments Off on Timing of Ocular Hypertension After Pediatric Closed-Globe Traumatic Hyphema: Implications for Surveillance

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