A-scan parameters and risk of phacomorphic glaucoma among kazakh population

doi:10.21203/rs.3.rs-1866315/v1

Purpose: The aim of our study was to identify risk factors parameters associated with PG in patients with mature cataract by comparing biometric parameters of contralateral eyes of patients with PG with eyes of patients with mature cataract.

Methods: This retrospective case - control study included 71 affected eyes with PG, 311 eyes of control participants and 71 contralateral eyes with PG. All participants were ethnically Kazakh. Axial length (AL), anterior chamber depth (ACD), lens thickness (LT) were measured using A-scan ultrasound biometry. To determine the cut-off value of the A-scan parameters associated with PG, we performed ROC analysis.

Results: The eyes with PG had the smallest AL, ACD and the largest LT, followed by the fellow eyes with PG and control eyes. There were no differences in age and sex between patients with PG and mature cataract. After adjustment for age and other A-scan parameters, continuous measures of AL and LT were associated with PG (OR 0.57, 95% CI 0.38 – 0.73, P < 0.001; OR 3.36, 95% CI 1.64 – 6.912, P = 0.001). When A-scan parameters were dichotomized according to the identified best-cut off, ACD less than 2.9 mm was strongly related to PG (OR 10.981, 95% CI 1.405 – 85.798, P < 0.001) as well as LT thicker than 4.8 mm (OR 29.245, 95% CI 11.212 – 76.283, P < 0.001).

Conclusions: We found that shorter AL, shallow ACD, and thick lens are risk factors for PG.

phacomorphic glaucoma

mature cataract

anterior chamber

axial length

lens

Senile cataract and glaucoma are the leading cause of blindness and low vision in the world [11–13; 18]. Glaucoma is a large group of eye disorders characterized by raising intraocular pressure (IOP) and damaging the optic nerve [21]. It is divided into two groups: primary and secondary glaucoma [14]. Phacomorphic glaucoma (PG) is one of the main types of secondary glaucoma, which develops because of a sharp swelling of the lens in mature cataract [24]. A senile cataract can progress from an immature state to mature cataract and sometimes develop PG [23]. When the cataract matures, the thickness of the lens increases, which creates a closer contact between the iris and the anterior surface of the lens, which leads to the development of the pupillary block [27].

Data on the worldwide distribution of PG are scarce and it is more common in Asian countries [3; 23; 26; 27]. In India, PG is a serious problem, and in the total number of cataract surgeries, PG accounts for about 3.91% [2]. PG is frequently associated with a lower social-economical class, possibly due to unequal access to ophthalmic screening and surgery [16; 19; 26]. Wong et al.[9] and Lee et al.[23] argued that higher incidence of PG in developing countries could be alternatively explained by the lack of education and less near work that lead to shorter, in tern a shorter axial length (AL) risk for PG. Although PG is very rare in Western countries, taking to account the increase in the elderly population, the incidence of PG in developed countries is expected to rise [5].

Cataract extraction is the only definitive treatment of PG that is able to timely reduce with IOP before the onset of acute glaucomatous optic neuropathy[2]. In most cases, the prognosis of visual acuity in PG depends on the disease duration and the level of IOP before surgery [16; 23; 28]. According to Sharanabasamma et al.[26], the prognosis of visual acuity in PG is satisfactory after surgical treatment in eyes IOP up to 35 mmHg and PG symptoms duration less than two weeks. When IOP is higher than 35 mmHg, optic atrophy occurs early. Therefore, it is important to identify biomarkers that can predict the development of PG in patients with mature cataract and help to diagnose it early.

To date, the main risk factors for PG are age older than 60 years, short AL, shallower anterior chamber depth (ACD), female gender[3; 15; 23]. However, the results of previous studies were conflicting and inconclusive. For this reason, there is currently no definite parameter of the eye that can be relied on to predict PG, in addition, there are ethnic differences in the parameters of the eye, which makes it difficult to generalize findings across different populations. Generally, studies on this problem have been conducted on small individual samples. Most studies did not notice the role of initial lens size as a risk factor for PG.

Biometric studies of eyes with PG may provide an explanation why not all cases with senile cataract lead to PG and thus help identify an eye at risk for developing PG. The aim of our study was to identify parameters associated with PG in patients with mature cataract by comparing biometric parameters of contralateral eyes of patients with PG with eyes of patients with mature cataract.

This retrospective case-control study was approved by the Kazakh National Medical University named after Asfendiyarov (Almaty, Republic of Kazakhstan) and Central Municipal Clinical Hospital’s (Almaty, Republic of Kazakhstan) Human Research Ethics Committee (N: 05 – 2020, 18.02.2020). This study adhered to the tenets of the Declaration of Helsinki.

This study involved adult patients diagnosed with PG and mature cataract, undergoing cataract surgery at the Central Municipal Clinical Hospital at Almaty, Republic of Kazakhstan. Data included in the study: scanned medical records of patients with PG with preoperative measurements from January 2015 to December 2019 and mature cataract from January to March 2019. During this period the total number of senile cataract surgeries were 12008, PG – 233 and PG accounts for about 1.95%. Patients with mature cataract were chosen as a control group because PG always develops in eyes with mature cataract, therefore, choosing healthy controls is not appropriate. Furthermore, because PG does not develop in all eyes with mature cataract, it is important to identify risk factors for PG in patients with mature cataract.

The total number of patients with PG were 233 and of them 141 were ethnically Kazakh, Caucasian – 64, other Asian – 28. From 141 Kazakh patients 70 were excluded because in 41 cases contralateral eyes with PG were pseudophakic, 19 cases the medical files had no ultrasound measurements of fellow eyes with PG, and 10 were suspected for APAC. PG differs from an acute primary angle closure (APAC) in the large thickness of the lens, normal depth of the ACD of the fellow eye, and sometimes an open anterior chamber angle.[14] APAC is bilateral, the anterior chamber angle is closed and the biometric parameters of the fellow eye have a closable angle [6]. The final number of included in this study patients with PG was 71 and patients with mature cataracts - 313 and all participants were Kazakh nationality.

Inclusion criteria were patients with PG in one eye and unilateral mature cataract, Kazakh ethnicity, completed medical records for age, gender, preoperative IOP, ACD between the corneal epithelium, lens thickness (LT) and AL measurements. Patients with other eye diseases, such as uveitis, retinal detachment, primary glaucoma, secondary glaucoma (except for PG), eye trauma, pseudophakic eye and early ophthalmic surgery were excluded.

PG was diagnosed when the following criteria were present: increased IOP above 30 mmHg, conjunctival injection, corneal epithelial edema, shallow anterior chamber, medium dilated pupil, swollen lens. IOP was measured using the Maklakov applanation tonometer (model NGM-2, 10 mg, Ocular Instruments Inc., Moscow, Russia). Gonioscopy was not performed due to corneal epithelium edema. The AL, ACD and LT were measured 10 times using 10 MHz A-scan biometry probe (A-scan plus, Accutome, USA) with applanation after 0.5% proparacaine hydrochloride instillation (Alcaine Alcon-Couvreur, Puurs, Belgium), then the mean values were estimated. These measurements were taken before cataract surgery and identified from the medical records.

Eyes that met the criteria were classified into 3 groups: (G1) eyes with PG (71 eyes); and (G2) control eyes that had mature cataract (311 eyes); (G3) unaffected fellow eyes with PG (71 eyes). During the phacomorphic attack, the ACD is shallower and the LT is greater than in the pre - phacomorphic state, that is why we cannot rely on these measurements to determine the risk factors for PG. To solve this problem, we compared the contralateral (i.e. unaffected) eyes of PG with control eyes on the assumption that this reflects the biometric parameters of the affected eyes before to the development of PG, because unaffected eyes of PG may represent an early stage of PG.

Statistical analysis

Descriptive analysis. Data with asymmetric distribution were analyzed using nonparametric tests. Mann-Whitney test was performed on age, IOP, AL, examine differences between groups (G1 and G2, G2 and G3) and results were presented as median (Me) and interquartile range (IQR). Pared data were analyzed by paired tests. Chi-square test used in the analysis of categorical variables.

Main analysis. The association between AL, ACD and LT and risk of PG was examined using binary logistic regression with adjustment for age, AL, ACD, LT (G2 and G3). ROC analysis was used to identify cut-off points for age, AL, ACD and LT to differentiate eyes with PG and mature cataract (G1 and G2). The best cut-off values were determined based on Youden’s index for these variables. In this statistical analysis, the cut-point that achieves maximum distance with chance level is calculated and is referred to as the optimal cut-point because it is the cut-point that optimizes the bioparameters’s differentiating ability when equal weight is given to sensitivity and specificity.AL, ACD and LT were dichotomized using the best cut-off point based on the Youden index for these variables[22]. Sensitivity, specificity and OR were calculated for each variable.

Additional analysis. The Spearman correlation was used to identify the relationship of AL, ACD and LT with age. Mann-Whitney test was used to identify differences in AL between women and men.

Statistical significance was defined as P < 0.05 for all analyses. Data analysis was performed in SPSS 26.0 (Chicago, IL, USA).

After excluding eyes with poor image quality and pseudophakic eyes, 71 eyes with PG (age, 69.0 years (63–77)), 71 fellow eyes with PG and 311 control eyes with mature cataract (age, 68.0 years (62–75)) were selected for ﬁnal analysis. All participants were Ethnic Kazakh. Demographic and clinical features of the study subjects are presented in Table 1. A significant difference in age and sex between PG and mature cataract was not (P = 0.197; P = 0.182). There was no significant difference in the laterality of disease (right/left eye) between the groups (P = 0.144). IOP was markedly higher in the group with PG than in the mature cataract (Me: 42 mmHg vs 14 mmHg, P < 0.001). IOP in contralateral eyes of patients with PG was 15 mmHg (IQR 14–17).

Table 1. Demographic and Clinical Features of the Study Subjects

Phacomorphic glaucoma

(n=71)

Mature cataract

(n=311)

P value

Age

(years),

Me [IQR]

69.0 (63–77)

68.0 (62–75)

0.197^a

Sex, n (%)

(male/female)

24 (33.8%)/

47(66.2%)

134 (43.1%)/

177 (56.9%)

0.182^b

Eye laterality,

n (%)

(right/left)

36 (50.70%)/

35 (49.30%)

164 (52.73%)/

147 (47.27)

0.144^b

IOP (mmHg),

Me [IQR]

42 (40-50)

14 (13-16)

0.001^*

N: number. Measurements are Me: Median, IQR: Interquartile range; IOP: intraocular pressure; ^aMann-Withney test. ^bChi-

square test. Bold value indicate statistically significant results.

Main analysis.

The median values of the A-scan biometry parameters in phacomorphic eyes, contralateral eyes of patients with PG, eyes with mature cataract and its association with PG are presented in Table 2. Eyes with PG had the shortest AL followed by contralateral eyes with PG and control groups. Likewise, eyes of PG had the shallowest ACD and the greatest LT followed by the contralateral eyes of patients with PG and control eyes. After adjustment for age and other A-scan biometry parameters, continuous measures of AL and LT were significantly associated with PG (OR 0.57, 95% CI 0.38 – 0.73, P < 0.001 and OR 3.36, 95% CI 1.64 – 6.912, P = 0.001, respectively).

Table 2. A-scan Parameters in Phacomorphic Eyes, Contralateral Eyes of Phacomorphic Glaucoma, Eyes with Mature Cataract and Results of Logistic Regression Analysis for Group G2 and G3

Group 1:

PG (n=71)

Group 2:

Mature cataract (n=311)

Group 3:

Contralateral eyes of PG

( n=71)

Crude

Odds ratio (95% CI)^*

G2 and G3

P*

G2 and G3

Adjustment odds ratio** (95% CI) G2 and G3

P**

G2 and G3

Age

(years),

Me [IQR]

69

(63– 77)

68 (62–75)

1.023

(0.997– 1.050)

0.088

1.017

(0.99– 1.045)

0.213

Sex

(M/F)

24 (33.8%)/

47(66.2%)

134 (43.1%)/

177 (56.9%)

0.674

(0.393– 1.158)

0.153

0.73

(0.413–1.293)

0.281

AL (mm), Me [IQR]

22.71(22.12– 23.39)

23.2

(22.64– 23.94)

22.79

(22.3– 23.4)

0.529

(0.390–0.719)

0.001

0.57

(0.38 – 0.73)

0.001

ACD (mm),

Me [IQR]

2.06

(1.9– 2.3)

2.7

(2.34 – 3.1)

2.48

(2.2 – 2.6)

0.43

(0.18 – 0.100)

0.001

1.15

(0.536– 2.45)

0.728

LT (mm),

Me [IQR]

5.03

(4.9– 5.22)

4.56

(4.18– 4.78)

4.79

(4.6 – 4.92)

43.817

(17.005– 112.905)

0.001

3.36

(1.64– 6.912)

0.001

To determine cut-off value associated with PG for the studied A-scan biometry parameters, we performed ROC analysis. Table 3 summarizes the best cut-offs, sensitivity at 80% specificity of different A-scan parameters and its association with PG. ACD less than 2.9 mm and LT thicker than 4.8 mm was significantly associated with PG (OR 10.981, 95% CI 1.405 – 85.798, P = 0.022, and OR 29.245, 95% CI 11.212 – 76.283, P < 0.001, respectively).

Table 3. Best Cut-Off Values, its Sensitivity at 80% Specificity and Results of Logistic Regression Analysis of A-scan Parameters

	Best cut-off level		Sensitivity at 80% specificity	PG (G1=71)	Mature cataract (G2=311)	Crude odds ratio (95%CI)	P^*	Adjustment odds ratio (95%CI)	P**
	Best cut-off level		Sensitivity at 80% specificity	Number of cases n (%)		Crude odds ratio (95%CI)	P^*	Adjustment odds ratio (95%CI)	P**
AL (mm)	<23,2		58	47(66.2)	159 (51.1)	1.876 (1.098– 1.098)	0.021	0.926 (0.473– 1.815)	0.823
ACD (mm)	<2,9		48	70 (98.6)	106(34.0)	38.85 (5.324– 283.498)	0.001	10.981 (1.405– 85.798)	0.022
LT (mm)	⩾4.8		85	66 (93.0)	72 (23.2)	43.817 (17.005– 112.905)	0.001	29.245 (11.212– 76.283)	0.001
Age (years)		⩾68	63	39 (54.9)	163 (52.4)	1.037 (0.618– 1.741)	0.89	0.89 (0.424– 1.543)	0.519
PG: phacomorphic glaucoma. G: group 1. N: number. CI: confidence interval. P^: crude logistic regression analysis. P*: adjustment logistic regression analysis. Bold values indicate statistically significant result.

Additional analysis. Results of our study showed, that with age, the depth of the anterior chamber decreases and the thickness of the lens increases. The correlation of ACD and LT with age was statistically significant (r_s= – 0.136, P = 0.008 and r_s= – 0.103, P = 0.045, respectively). There was no correlation between AL and age (r_s= – 0.045, P = 0.379). The difference in median AL between men and women was statistically significant (23.24 mm (IQR 22.77 – 24.70)) vs. (23.07 mm (IQR 22.53 – 23.80), respectively, P = 0.038).

In this case-control study, short AL, shallow ACD and thicker lens were found to be risk factors associated with PG. Also, with advancing age, the depth of the anterior chamber decreases and the thickness of the lens grows, which increases the chances of developing PG in short eyes.

Previous studies found that elderly age, female sex, shorter AL and shallower ACD are risk factors for developing PG [3; 15; 23]. Axial length is one of the important parameters for development of various types of glaucoma. For primary open-angle glaucoma and normal-tension glaucoma, the longer AL is a risk factor, also shorter AL risk for primary angle-closure[10; 12; 20].This conform to the results of Lee et al. that reported that eyes with AL shorter than average AL < 23.7mm were 4.3 times higher for developing PG [23]. In contrast, in two other studies undertaken by Subbiah et al.[27] and Mansouri et al.[3] there was no difference in mean AL between PG eyes and eyes with mature cataract. Also, Keles et al.[15] found that AL < 23.22mm had a higher risk (OR 1.8, P = 0.124) for developing of PG, but the result was not significant due to the small number of patients with PG. We found significant difference in AL between contralateral eyes with PG and eyes with mature cataract (P = 0.001). However, the association between AL and PG diminished after adjustment. Different conclusions of several works are also possible due to the ethnic differences in anatomical and biometric parameters of the eye^.[7].

Several previous studies didn’t find any significant difference in ACD between contralateral eyes with PG and mature cataract, possibly because of small sample size and differences in ethnicity [15; 23; 27]. During the phacomorphic attack, the ACD is shallower and the LT is greater than in the pre-phacomorphic status, which measurements are meaningless for further study. In population-based studies on ethnic Chinese in Singapore, right and left eyes showed a similar pattern of associations, so unaffected eyes of PG may represent an early stage of PG [8]. In our study, we found a significant difference in ACD between the contralateral eyes with PG (G3: 2.48 mm (IQR 2.2 – 2.6)) and the eyes with mature cataract (G2: 2.7 mm (IQR 2.34 – 3.1)), P < 0.001. Eyes with ACD ≤ 2.9 mm had a higher risk of PG compared with eyes to ACD > 2.9 mm (OR 24.20, 95% CI 3.435 – 170.71, P < 0.001).

Our findings suggest that in addition to the AL and ACD, the thickness of the lens could also be an important risk factor for PG. Many previous studies did not consider the lens thickness of the contralateral eyes with PG as a risk factor for developing PG. For example, Lee et al.[23] and Keles at al.[15] considered using contralateral eye’s lens thickness measurements to be incorrect because these LT values are surely different from the pre-phacomorphic state. If according to population-based Chinese studies, the eye parameters of both eyes are similar, then why we cannot use the LT of the contralateral eyes with PG as a prototype of the pre-phacomorphic lens[8]. In our study, we found a significant difference in LT between the contralateral eyes with PG (G3:4.79 mm(IQR 4.6 – 4.92)) and control eyes (G2: 4.79 mm(IQR 4.6 – 4.92)), P < 0.001). Our study suggested that LT should not be ignored as a predictor factor because eyes with LT ⩾ 4.8 mm had higher risk of PG (OR 29.245, 95% CI 11.212 – 76.283).

Prophylactic laser iridotomy is not recommended for the contralateral eye of PG, only lens removal is considered the optimal approach to prevent PG [3]. Therefore, knowing the measures of LT and considering the AL and ACD parameters, we can assume the risks of PG development in eyes with senile cataract.

Many studies on PG confirmed, that the risk of developing PG also increases with elderly age [15; 23; 27]. Several studies or two studies mean age of patients varied from 72 to 74 years and the mean age of PG patients was significantly higher than that of mature cataract [3; 15]. In contrast, we found no significant difference in the age of participants with PG (69 years (IQR 63 – 77)) and mature cataract (68 years (IQR 62 – 75), (P < 0.197)). We hypothesize that Kazakhs have a shorter AL, a smaller ACD, and a thicker lens, perhaps for these reasons they have accelerated development of PG.

Koretz et al.[1] reported that there was no change in AL with age, but some studies have shown that AL decreases with age.[4; 25] In a study Praveenet al.[17] found, that with advancement in age a significant decrease in ACD with increase in lens thickness. We observed similar results, in our data ACD decreased with increasing age (P = 0.008) and lens thickness increased (P = 0.045), but we did not find an association between age and AL (P = 0.379). With increasing age, the thickness of the lens increases, which could lead to decreased ACD and in eyes with short AL, and increased risk of PG development.

Some authors noticed, that PG is more common among women [2; 26]. These findings may be related to the fact that women have a shorter AL and a shallower ACD than men. In our data, there was a statistically significant difference in AL between men and women (23.24 mm (IQR 22.77 – 24.70) vs. 23.07 mm (IQR 22.53 – 23.80), respectively, P = 0.038), but there was not any significant difference in sex between PG and control groups.

This study had some limitations. Firstly, it was retrospective case-control study. Although every effort was made to obtain patient information, there were still inherent flaws in retrospective studies. Unfortunately, we were unable to obtain accurate biometric parameters of ACD and LT before the presence of PG, as all patients were admitted with an attack of PG. To determine the exact risk factor for PG, a cohort study would certainly have been better, because of the small prevalence of PG in patients with mature cataract and because it can take decades to develop PG, it is not feasible to design and conduct cohort study. Secondly, the subjects were of Kazakh origin, and the results of this study may not be generalized to all ethnic groups. Thirdly, in our study, the best cut-off is taken from the general parameter of the groups under study, but it would be ideal if a population study among Kazakh nationalities was conducted to determine the mean eye parameters. In our country, population-based study of biometric parameters among Kazakh nationalities has not been done yet. In the future, if a cross-sectional population study of biometric parameters of the eye between different nationalities is conducted, perhaps we can get an answer to our questions about the differences of biometric parameters of the eye in different nationalities.

In conclusion, short AL, shallow ACD and thicker lens are risk factors for developing PG. Knowing the measures of AL, ACD and LT parameters, we can anticipate the risks of PG development in eyes with senile cataract. Therefore, they should be included in the screening protocol for older adults with risk factors for PG so the decision about cataract surgery is made early, especially in developing countries. Further studies a needed to evaluate the effectiveness of including these parameters in a screening program.

ACKNOWLEDGEMENTS

The authors thank Rysty Erkynbek, Aygerym Saktan, Tunyk Ualyeva, Guldariya Kanatbek, Kayumova Khurshida for assistance in the date collection and Akbope Myrkassymova for helping date entry and statistical analysis.

Disclosure of potential Conflicts of Interest: The authors declared no potential conflicts of interest with respect to the research, authorship, and publication of this article.

Funding/Support: The authors received no financial support for the research, authorship, and/or publication of this article.

Minassian, DC, Mehra, V. 3.8 million blinded by cataract each year: projections from the first epidemiologicaltudy of incidence of cataract blindness in India. Br J Ophthalmol 1990;74:341–3. https://doi.org/10.1136/bjo.74.6.341
Flaxman, SR, Bourne, RRA, Resnikoff, S, et al. Global causes of blindness and distance vision impairment 1990–2020: a systematic review and meta-analysis. Lancet Glob Heal 2017;5:e1221–34. https://doi.org/10.1016/S2214-109X(17)30393-5
Foster, PJ, Baasanhu, J, Alsbirk, PH, et al. Glaucoma in Mongolia. A population-based survey in Hövsgöl province, northern Mongolia. Arch Ophthalmol 1996;114:1235–41. https://doi.org/10.1001/archopht.1996.01100140435011
Tham, YC, Li, X, Wong, TY, et al. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology 2014;121:2081–90. https://doi.org/10.1016/j.ophtha.2014.05.013
Lee, JWY, Lai, JSM, Yick, DWF, Yuen, CYF. Prospective study on retinal nerve fibre layer changes after an acute episode of phacomorphic angle closure. Int Ophthalmol 2012;32:577–82. https://doi.org/10.1007/s10792-012-9614-5
Kanski, J, Brad, B. Clinical ophthalmology: a systematic approach. 7th ed. Philadelphia, PA; 2011.
Lee, JWY, Lai, JSM, Yick, DWF, et al. Retrospective case series on the long-term visual and intraocular pressure outcomes of phacomorphic glaucoma. Eye 2010;24:1675–80. https://doi.org/10.1038/eye.2010.108
Lee, JWY, Lai, JSM, Lam, RF, et al. Retrospective analysis of the risk factors for developing phacomorphic glaucoma. Indian J Ophthalmol 2011;59:471–4. https://doi.org/10.4103/0301-4738.86316
Subbiah, S, Thomas, PA, Nelson, JCA. Comparison of ultrasound biomicroscopy and ultrasonographic parameters in eyes with phacomorphic glaucoma and eyes with mature cataract. Int Ophthalmol 2017;37:849–58. https://doi.org/10.1007/s10792-016-0343-z
Sharanabasamma, M, Vaibhav, K. Management and Visual Outcome in Patients of Lens-induced Glaucomas at a Tertiary Eye Care Hospital in South India. J Curr glaucoma Pract 2016;10:68–75. https://doi.org/10.5005/jp-journals-10008-1204
Mansouri, M, Ramezani, F, Moghimi, S, et al. Anterior segment optical coherence tomography parameters in phacomorphic angle closure and mature cataracts. Investig Ophthalmol Vis Sci 2014;55:7403–9. https://doi.org/10.1167/iovs.14-14748
Angra, SK, Pradhan, R, Garg, SP. Cataract induced glaucoma-an insight into management. Indian J Ophthalmol 1991;39(3):101.
Sitoula, RP, Sarkar, I, Nayak, D et al. Lens induced glaucoma: An experience in tertiary eye care center in eastern Nepal. Nepal J Ophthalmol 2016;8:161–6. https://doi.org/10.3126/nepjoph.v8i2.17006
Jain, IS, Gupta, A, Dogra, MR, et al. Phacomorphic glaucoma-management and visual prognosis. Indian J Ophthalmol 1983;31:648.
Wong, TY, Foster, PJ, Johnson, GJ, Seah, SKL. Education, socioeconomic status, and ocular dimensions in Chinese adults: the Tanjong Pagar Survey. Br J Ophthalmol 2002;86:963–8. https://doi.org/10.1136/bjo.86.9.963
Senthil, S, Chinta, S, Rao, HL, et al. Comparison of cataract surgery alone versus cataract surgery combined with trabeculectomy in the management of phacomorphic glaucoma. J Glaucoma 2016;25:e209–13.10. https://doi.org/1097/IJG.0000000000000229
Ramakrishanan, R, Maheshwari, D, Kader, MA, et al. Visual prognosis, intraocular pressure control and complications in phacomorphic glaucoma following manual small incision cataract surgery. Indian J Ophthalmol 2010;58:303–6. https://doi.org/10.4103/0301-4738.64136
Keleş, A, Şen, E, Elgin, U. Evaluation of biometric parameters in phacomorphic glaucoma and mature cataracts. Eur J Ophthalmol 2021;31:1101–6. https://doi.org/10.1177/1120672120914536
Moghimi, S, Fathollahzadeh, N, Chen, R, et al. Comparison of Fellow Eyes of Acute Primary Angle Closure and Phacomorphic Angle Closure. J Glaucoma 2019;28:194–200. https://doi.org/10.1097/IJG.0000000000001167
Reiser, B. Measuring the effectiveness of diagnostic markers in the presence of measurement error through the use of ROC curves. Stat Med 2000;19:2115–29. https://doi.org/10.1002/1097-0258(20000830)19:16<2115::aid-sim529>3.0.co;2-m
Casson, RJ, Baker, M, Edussuriya, K, et al. Prevalence and determinants of angle closure in central Sri Lanka: the Kandy Eye Study. Ophthalmology 2009;116:1444–9. https://doi.org/10.1016/j.ophtha.2009.03.005
Jonas JB, Aung T, Bourne, RR, Bron, et al. Glaucoma. Lancet 2017;390:2183–93.10. https://doi.org/1016/S0140-6736(17)31469-1
Yoon, JJ, Misra, SL, Mcghee, CNJ, et al. Demographics and ocular biometric characteristics of patients undergoing cataract surgery in Auckland, New Zealand. Clin Experiment Ophthalmol 2016;44:106–13.10. https://doi.org/1111/ceo.12634
Lavanya, R, Wong, TY, Friedman, DS, et al. Determinants of angle closure in older Singaporeans. Arch Ophthalmol 2008;126:686–91. https://doi.org/10.1001/archopht.126.5.686
Koretz, JF, Kaufman, PL, Neider MW, et al. Accommodation and presbyopia in the human eye–aging of the anterior segment. Vision Res 1989;29:1685–92. https://doi.org/10.1016/0042-6989(89)90150-8
Rozema, JJ, Ní Dhubhghaill, S. Age-related axial length changes in adults: a review. Ophthalmic Physiol Opt 2020;40:710–7. 10. https://doi.org/1111/opo.12728
Lee, K E, Klein, BE, Klein, R, et al. Association of age, stature, and education with ocular dimensions in an older white population. Arch Ophthalmol 2009;127:88–93. https://doi.org/10.1001/archophthalmol.2008.521
Praveen, MR, Vasavada, AR, Shah, SK, et al. Lens thickness of Indian eyes: impact of isolated lens opacity, age, axial length, and influence on anterior chamber depth. Eye 2009;23:1542–8. https://doi.org/10.1038/eye.2008.315

No competing interests reported.

A-scan parameters and risk of phacomorphic glaucoma among kazakh population

Status:

Version 1

Abstract

Introduction

Materials And Methods

Results

Discussion

Conclusions

Declarations

References

Additional Declarations

Status:

Version 1