Original Article
Incidence of Primary Open Angle Glaucoma in Patients Presenting
with Retinal Vein Occlusion
Ch. Javed Iqbal, Muhammad
Salman Hamza, Ch. Nasir Ahmed, Qunber Abbas, Muhammad Awais Asghar
Pak J Ophthalmol 2019, Vol. 35, No. 2
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See end of article for authors affiliations …..……………………….. Correspondence to: Prof. Ch. Javed Iqbal
MBBS, MCPS, FCPS, Fellowship in
Vitreoretina
Professor of Ophthalmology
11-A
Nursery lane Lawrence road Lahore
Email: drj4eye@yahoo.com
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Purpose: To determine the incidence of primary open angle glaucoma in
patients presenting with Retinal vein occlusion in tertiary care hospital. Study Design and Place of
Study: Cross-sectional study. Place and Duration of Study: Eye Unit II, Institute of Ophthalmology, King Edward Medical
University, Mayo Hospital, Lahore.
from January 2016 to December 2017. Material and Methods: A sample size of 100 cases was calculated with 95% confidence
level, 5% margin of error. Non-probability consecutive sampling was done.
Adult patients of either gender presenting with retinal vein occlusion (RVO)
diagnosed within a month were included in the study. The demographic
information and Visual Acuity were recorded and a detailed slit lamp
examination, gonioscopy and fundoscopy was carried out. Applanation tonometry
for Intra ocular pressure (IOP) measurement was performed. Central corneal
thickness was measured and the correction factor was applied. If there was
raised Intraocular pressure (> 20 mm Hg), then patient was labeled as
glaucoma. Data was collected and analyzed by SPSS. Data was stratified. Post
stratification, Chi-square was applied. Results: The mean age was 46.28 ± 15.02 years. On gender basis male were
found more involved as ratio was 1.6: 1. The Mean intraocular pressure was
15.87 ± 4.52 mm Hg. Primary open angle glaucoma was found in 14 (14%) of
patients. Conclusion: Our Study concluded that the incidence of glaucoma is
significant in patients presenting with Retinal vein occlusion (RVO) in local
population. Keywords: Primary Open Angle Glaucoma,
Retinal Vein Occlusion, Intraocular Pressure. |
Among the
retinal vascular diseases Retinal vein occlusion (RVO) is the second common reason
of vision loss after diabetic retinopathy1. Central and branch
retinal vein occlusion are its two distinct types based upon site of occlusion.
Its prevalence varies from 0.7% to 1.6% in different studies2. The
pathogenies of acute RVO is still not well understood3. The natural
history of RVO is variable, many patients have good prognosis with one study
showing half of patients achieved 20/40 vision after 6 months without treatment4.
Other causes of vision loss due to RVO include cystoid macular edema, neovascularization
leading to vitreous hemorrhage, retinal detachment or glaucoma5.
Glaucoma is a
specific form of optic neuropathy causing irreversible blindness and second
most common cause to blindness worldwide6. Relationship between RVO
and glaucoma has been well established since the start of the 20th century1.
In one study
the percentage of central retinal vein occlusion was 25% while for BRVO was
8.6% in diagnosed case of chronic simple glaucoma7. Hayreh reported prevalence
of RVO among glaucoma was higher than normal population i.e. approximately 10%5,8.
The Eye Disease Case-Control Study, in a large series of patients with RVO,
found that in all types of RVO, history of glaucoma was found9.
So, aim of
this study was to find the incidence of glaucoma in patients presenting with
RVO in a tertiary care Hospital. In RVO the comorbidity of glaucoma enhances
the severity of RVO. Timely diagnosis and management can prevent patients from
permanent vision loss. Literature has reported that in few cases of RVO
glaucoma occurs, but some studies reported little higher incidence/prevalence.
Moreover, no local evidence was available regarding this issue
which can discover the extent of glaucoma in RVO cases in local population,
knowing the exact incidence can help in setting the guidelines for prevention
of glaucoma in RVO cases.
MATERIAL AND METHODS
This
observational study was conducted in Eye Unit II, Institute of Ophthalmology,
King Edward Medical University, Mayo Hospital, Lahore for two years from Jan
2016 to December 2017. A sample size of 100 cases was calculated with 95%
confidence level, 5% margin of error and taking expected % glaucoma 9.9% in patients
presenting with retinal vein occlusion. Non-probability consecutive sampling
was done.
Patients’ age ranging from 18 to 70 years of either gender presenting
with RVO diagnosed (history of loss of vision and fundoscopy show dilation and tortuosity
of vein with retinal hemorrhages) within a month were included in the study.
Patients with history of ocular trauma or surgery for glaucoma, previous
corneal opacity and base line visual acuity of no perception of light (NPL)
were excluded from the study. Patients were registered from Outpatient
Department (OPD), an informed consent was taken. The demographic information
like name, age, sex and address was recorded. Visual Acuity of all the patients
was recorded by Snellen’s visual acuity chart. A detailed slit lamp examination
with fundoscopy carried out by 90D and 66D fundus lenses and gonioscopy was
carried out with Goldman three mirror gonioscopy lens to confirm the diagnosis
of retinal vein occlusion and primary open angle glaucoma. Examination of
fellow eye was also carried out. All the patients then underwent applanation
tonometry for the Intra ocular pressure measurement. Central corneal thickness
was measured and the correction factor was applied. If there was abnormally
raised Intraocular pressure (> 20 mm Hg), then patient was labeled as glaucoma
as per operational definition of study. All the information was collected on a
predesigned proforma. No ethical issue and risk was involved. Data was analyzed
by SPSS version 17. The quantitative variable like age was presented as mean
and standard deviation The Qualitative variable like gender and glaucoma were
presented as frequency and percentage. Data was stratified for the age, gender
and duration of RVO, history of Diabetes Mellitus and hypertension. Post stratification,
Chi-square was applied taking p –value < 0.05 as significant.
RESULTS
The mean age was 46.28 +- 15.02 years among the patients. There
were 62% male patients while 38% female patients (Figure 1).
Fig. 1: Gender Distribution.
The
male/female ratio was 1.6 to 1. Hypertension was present in 46 (46%) patients
and diabetes mellitus was present in 28 (28%) patients (Figure 2).
The mean IOP of the patients was 15.87 ± 4.52 mm Hg and glaucoma was
observed in 14 (14%) patients (Figure 3).
Fig. 2:
Fig. 3: Incidence of glaucoma.
Fig. 4: Glaucoma gender distribution.
The study
results showed that among 47 patients of age less than 45 years, glaucoma was
found in 4 cases but in 53 patients of age ≥ to 45 years, glaucoma was
found in 10 cases. Statistically there is insignificant difference found
between the glaucoma with age i.e. p-value = 0.160. Similarly, among 62 males
glaucoma was found in 9 cases while out of 38 females glaucoma was found in 5
cases. Statistically there is insignificant difference found between glaucoma
with gender i.e. p-value = 0.849 (Figure 4).
Among 51 patients who had duration of RVO less than or equal to 2
months glaucoma was found in 5 cases and in 49 patients who had duration of RVO
> 2 months, glaucoma was found in 9 cases but the difference was insignificant
i.e. p-value = 0.217. Among 46 hypertensive patients glaucoma was found in 7
cases. The difference was insignificant i.e. p-value = 0.746. In 28 diabetic
patients, glaucoma was found in 10 cases but in 72 non diabetic cases, glaucoma
was found in 4 cases. Statistically there was significant difference found
between the glaucoma with Diabetes Mellitus i.e. p-value= 0.000 (Table 2).
DISCUSSION
Glaucoma
encompasses group of ophthalmic diseases that ultimately result in progressive
optic neuropathy and loss of visual function. Retinal vein occlusion is an
important cause of loss of vision. Glaucoma and retinal vein occlusion have an
important causal relationship with one another. Most of the information about
this relationship comes from case control studies, clinical trials and clinical
case series.
The second
leading cause of bilateral blindness is glaucoma i.e. about 8.4 million people
have bilateral blindness because of glaucoma (4.5 million people having Open Angle
Glaucoma (OAG) and 4 million people having Angle closure glaucoma (ACG). In
United States, in 2004 about 2.2 million people were suffering from Primary
open angle glaucoma (POAG) and the burden is estimated to rise to 3.36 million
by 202010.
Hayreh SS et al reported that the overall prevalence of glaucoma was
9.9% in patients with RVO5. Fu Chan et al supported the evidence and
reported the frequency of glaucoma 9.3% among patients with RVO11. While
in our study the incidence of glaucoma was 14% in the patients diagnosed as
RVO, which appears higher as compared to the other studies.
While another
study conducted by B Jonas et al found the frequency of glaucoma in 1.59%
cases, among them it was more common in CRVO (18.9%) as compared to BRVO (2.7%)12.
A study by
Hirota A et al showed highest incidence of primary angle closure exhibiting
Retinal Vein Occlusion by reporting 8.1% prevalence13.
One study by
da Silva et al showed that prevalence of ocular hypertension and glaucoma was
3.74% (4 patients) and 2.8% (3 patients) respectively. When considering age
wise, patients > 40 years, the prevalence of ocular hypertension and
glaucoma was 5.4% (4 patients) and 4.76% (3 patients) respectively14.
The Geneva
Study (2010) showed that hypertension was found in 64% of patients and diabetes
in 12% of 1267 patients with occlusion of retinal vein (central/branch retinal
vein occlusion), while in our study 46 patients were hypertensive out of which
7 were diagnosed as a case RVO15.
Study
conducted by Sperduto et al found an association of CRVO with increased systemic hypertension,
diabetes, and glaucoma. These associations were higher association with
ischemic CRVO. This study compared 258 patients diagnosed with CRVO over four
years span in five centers with 1142 age matched controls. These controls were
recruited a year after diagnosis of CRVO from same eye clinics9,16. However,
in one Study, for example, Klein and associates at the 5 year follow-up were
unable to find an association between Ocular hypertension (OHT), IOP, BRVO and
glaucoma17,18.
Studies conducted by Frucht J et al, Amelie P et al and Appiah AP et al reported a higher frequency of raised
IOP in cases of occlusion of central retinal vein as compared with branch retinal
vein4,19,20. As a result of above discussed findings in future there
a need to find individual incidence’s of different RVO subtypes. These results
are comparable with the results of our study.
Our study does have some limitations
like small sample size and was conducted in only one tertiary care center. It is
proven that with our study and other that there is strong association between
glaucoma and retinal vein occlusion. It is recommended that multicenter future
studies are required to find out the exact incidence of the patients with CRVO
for the presence of glaucoma.
CONCLUSION
Our study concluded that
the incidence of glaucoma was significant in patients presenting with retinal
vein occlusion (RVO). The frequency seems to be high. So it is recommended that
every patient with RVO should be screened for Glaucoma.
Author’s Affiliation
Author’s Contribution
Prof. Ch. Javed Iqbal
Selection of topic, Data
collection and data analysis.
Dr. Muhammad Salman
Hamza
Data collection,
manuscript writing and data analysis.
Dr. Ch. Nasir Ahmed
Data collection and data
analysis.
Dr. Qunber Abbas
Data collection and data
analysis.
Dr. Muhammad Awais
Asghar
Data compilation and
statistical analysis.
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